Platinum Palladium Rhodium Purification Equipment

— Turnkey Platinum Palladium Rhodium Purification Equipment

A Platinum Palladium Rhodium Refining Equipment set is a turnkey wet-chemistry PGM refinery that dissolves, separates and purifies platinum, palladium and rhodium out of spent catalysts, catalytic converters, jewellery sweeps, e-waste fractions and refinery residues, and delivers them as individual, saleable metals at Pt ≥ 99.95%, Pd ≥ 99.95% and Rh ≥ 99.90%. Feed is attacked in aqua regia, or in hydrochloric acid with chlorine as the oxidant, inside enclosed glass-lined, titanium or PP reactors; silver is stripped out with sodium chloride and gold with anhydrous sodium sulfite; platinum is then precipitated as ammonium chloroplatinate and palladium as ammonium chloropalladate, while rhodium is separated through ammonium sulfite complexation and ligand substitution — the only route that reliably splits rhodium from iridium. Direct PGM recovery reaches up to 99% on suitable feed from about 5% PGM content upward.

Product Overview

Platinum palladium rhodium purification equipment is the metal-end purification stage of a precious-metal refinery — the plant that takes an already-separated PGM fraction and lifts it to a purity grade a buyer will accept without a discount, while keeping the residual impurities under assay control. It is a different job from dissolution and separation, and it is designed as a different plant.

That distinction matters, because the word purification is used loosely across the industry. In this system, purification means metal-end purity: raising the fineness of the finished platinum, palladium and rhodium itself, and removing what is left in them. It does not mean solution-end polishing — the raffinate and bleed treatment that takes a waste stream from ppm to ppb. Both jobs exist in a refinery, and serious buyers ask for both, but they need different equipment: solution-end polishing is done with membranes, ion-exchange resin and carbon; metal-end purification is done with re-crystallisation chemistry, controlled calcination and hydrogen reduction. This page describes the second. Where a client also needs the polishing loop, it is supplied as a separate module and tied into the same metal-accounting system.

The feed to a purification line is material that has already been concentrated to a workable grade. In practice that means crude platinum, palladium or rhodium metal above about 90% assay, the PGM salts and solutions produced by a separation train, strip liquor from solvent extraction, loaded ion-exchange eluate, PGM anode slime and refinery residue concentrates, and the alloy or powder produced by smelting or fusion of spent catalysts. Leaner material belongs upstream, in pre-concentration and separation; the economics of purification are set by how little non-PGM mass is carried into the reactors.

The chemistry is what the equipment exists to serve. Platinum and palladium purify well because their compounds have convenient solubilities: in acid media platinum forms a sparingly soluble ammonium chloroplatinate that leaves base metals and the other platinum-group metals in solution, and in alkali media it forms a soluble hydroxo complex that leaves other metals behind as hydrolysis precipitates. Palladium forms a dark red crystalline ammonium chloropalladate that base metals do not, and it also forms a soluble tetraammine complex that can be swung back to a precipitate with acid. Rhodium is the exception. Rhodium(III) chloro-complexes are kinetically stable, so rhodium cannot be separated by the valence tricks that work on its neighbours; its purification depends on changing the ligands — sulfite, then ammonia — to build complexes with different solubilities from iridium’s. That is why rhodium purification is a two-stage operation (make a pure rhodium compound, then make pure rhodium metal), why a single ammonium sulfite pass separates most of the iridium but recovers only about 95% of the rhodium, and why the process rule in this plant is strict: a rhodium solution or precipitate is never converted back to metal until its purity has been confirmed by assay.

The equipment therefore looks different from a gold refinery. PGM purification batches are small — grams to tens of kilograms — and each batch can be worth more than the machinery around it. The reaction train is built inside a sealed reaction fume hood, reactions run in PP or glass-lined buckets and in borosilicate glassware where the operator can see the colour change that tells him the reaction has gone far enough, separation happens in filters and vacuum filter plates rather than by pouring, and solution is moved by vacuum liquid lifting so that nothing is decanted by hand. Vessels are chosen against the actual duty: borosilicate glass where visibility and cleanliness matter, titanium for chloride liquors, glass-lined (enamel) steel for acid service, and anti-ageing PPH for neutralisation and scrubbing. The design brief is unglamorous and deliberate: low equipment investment, low running cost, high visibility, and no place for metal to hide.

The gas and liquid circuits are part of the purification package rather than a downstream problem. Dissolving crude PGM metal in aqua regia, or removing nitric acid from a palladium solution, produces a concentrated nitrogen-oxide stream, so the reactor mouth is sealed, the vapour is condensed and the condensate — which carries dissolved metal — is returned to the batch. The remaining gas goes to a multi-stage absorption tower that takes inlet nitrogen oxide of the order of 30,000 mg/m³ (about 20,000 ppm in a typical batch) below 150 ppm, at 99.5% absorption efficiency, and that also absorbs chlorine and sulfur dioxide. Effluent is segregated, neutralised in PPH neutralisation vessels and polished, and the rinse water is returned to the wash loop rather than discharged with metal in it.

The outcome is a compact, cyanide-free, assay-controlled purification plant that a refinery, catalyst recycler, jewellery manufacturer, e-waste processor, glass plant or precious-metal trader can run on its own site: crude PGM in, 4N platinum, palladium and rhodium out, every batch documented, and the purity upgrade loop — assay, re-dissolve, re-precipitate — built into the way the plant is operated rather than improvised.

Application Scenarios

Platinum palladium rhodium purification equipment is specified wherever PGM has already been separated but not yet brought to a grade that can be sold, certified or used, and where the operator wants to own that last and most valuable step.

Precious-metal refineries and assay houses — upgrade crude Pt, Pd and Rh, or the salts and strip liquors produced by their own separation train, to 4N metal. Output: assay-certified Pt / Pd / Rh ≥ 99.95–99.99%.
Automotive catalyst recyclers — take the PGM concentrate or crude alloy recovered from three-way catalysts to separate, saleable metals instead of selling a mixed product at a discount. Output: Pt, Pd and Rh metal to specification.
Spent-catalyst reclaim plants — purify palladium-on-carbon, platinum reforming and rhodium hydroformylation catalyst residues back to metal. Output: Pt / Pd ≥ 99.99%, Rh ≥ 99.95%.
Petrochemical and fine-chemical producers — purify in-house catalyst change-out material rather than surrendering it to a third-party refiner and its charges. Output: recovered PGM metal with an in-house assay record.
Jewellery, watch and precious-metal workshops — purify platinum and palladium alloy scrap, sweeps, filings and polishing dust on site and on a short cycle. Output: 4N Pt and Pd for re-alloying or sale.
Glass, optical fibre and crystal producers — purify platinum and rhodium recovered from spent bushings, stirrers, crucibles and platinum-rhodium ware, keeping the two metals apart. Output: separate Pt and Rh metal powder.
Electronic and e-waste refiners — purify the PGM alloy, MLCC residue or pregnant liquor generated by PCB processing. Output: Pd and Pt metal, with Au and Ag on the same site.
Copper-nickel smelters and anode-slime processors — purify the PGM fraction of anode slime and refinery residue on site. Output: individual PGM metals and base-metal by-products.
Hydrogen and fuel-cell supply chains — purify platinum recovered from membrane electrode assemblies and electrolyser stack scrap. Output: Pt ≥ 99.99% sponge and powder.
Dental, medical and laboratory operations — purify Pt, Pd and Rh from alloy scrap, crucibles, thermocouple wire and bench residues. Output: high-purity PGM powder.
Precious-metal traders, banks and mints — re-purify contaminated, off-spec or mixed PGM back to certified fineness with batch traceability. Output: certified sponge, powder and bars.
Universities, institutes and pilot facilities — bench-scale purification trains for process development, method validation and teaching. Output: analytical-grade Pt, Pd and Rh.

Applicable Raw Materials

Route selection starts from the assay. Platinum palladium rhodium purification equipment is fed with material that has already been separated — typically a crude metal above about 90% assay, or a PGM salt, strip liquor or eluate of equivalent metal content. Material that still carries a large non-PGM mass is pre-concentrated and separated first, because purification pays for itself only when the reactors are carrying metal rather than gangue.

Crude platinum metal above 90% assay — the classic purification feed, normally dissolved in aqua regia and taken through repeated ammonium chloride precipitation. Output: 4N platinum sponge, and 5N on suitable feed.
Crude palladium metal and palladium-bearing chloro-acid solutions — crude palladium is dissolved in aqua regia, concentrated to destroy nitric acid and re-dissolved in hydrochloric acid before precipitation. Output: Pd ≥ 99.99% sponge and powder.
Crude rhodium metal and rhodium residue — dissolved by sodium bisulfate fusion with dilute sulfuric acid leaching, by medium-temperature chlorination roasting with dilute hydrochloric acid leaching, by activation followed by aqua regia, or electrochemically. Output: Rh ≥ 99.95% powder, or a pure rhodium compound.
PGM salts and solutions from a separation train — ammonium chloroplatinate, ammonium chloropalladate, ammonium chlororhodate and their solution forms. Output: purified metal of the corresponding metal.
Strip liquor and eluate from solvent extraction and ion exchange — loaded organic strip solutions, amine or phosphine oxide strip liquors, and ion-exchange eluates. Output: purified single-metal liquor for reduction.
PGM concentrates, alloys and matte-derived powder — PGM-enriched powder, alloy button or matte produced by smelting or selective leaching of catalysts and e-waste, at a grade that goes straight to dissolution. Output: separate Pt, Pd and Rh metal.
Anode slime and refinery residue concentrates — copper-nickel electrorefinery slime and precious-metal refinery tail residues after base-metal removal. Output: individual refined PGMs, with base metals as by-products.
Platinum-rhodium ware and high-temperature components — thermocouple wire, gauze, bushings, stirrers, crucibles, nozzles and contaminated refractory material. Output: separated Pt and Rh powder.
Spent catalyst concentrates — palladium-on-carbon, Pt reforming, Pd hydrogenation and Rh hydroformylation catalysts after support removal. Output: Pt / Pd ≥ 99.99%, Rh ≥ 99.95%.
Electronic precious-metal fractions — PGM alloy, connector and contact scrap, multilayer ceramic capacitor residues and PCB-derived concentrate. Output: Pd and Pt metal, with Au and Ag co-products.
Spent plating, electrolyte and ion-exchange material — platinum and palladium plating baths, drag-out and strip solutions, spent electrolyte, loaded resin and activated carbon. Output: recovered PGM metal and recyclable liquor.
PGM-bearing dilute streams from the same site — wash water, bleed and scrubber liquors, recovered as a concentrated eluate rather than neutralised to waste. Output: eluate returned to the purification train.

Output Products

Every consignment leaves the line against a Certificate of Analysis produced by fire assay with ICP-OES confirmation and ICP-MS verification at trace level, and each metal is packaged in the form its buyer wants — sponge, powder, granules or cast bar.

Purified platinum (4N standard, 5N available) — separated as yellow ammonium chloroplatinate, washed with acidified ammonium chloride, re-dissolved and re-precipitated as required, then calcined and hydrogen-reduced. Pt ≥ 99.99% as the standard grade, with up to 99.999% (5N) produced on suitable feed and repeated precipitation cycles. Output: platinum sponge, powder, and cast bars, granules or buttons on request.
Purified palladium (4N) — precipitated as dark red crystalline ammonium chloropalladate, cycled through slurry-and-boil reduction and re-oxidation, then purified by ammonia complexation and acidification and reduced to metal. Pd ≥ 99.99%, with higher grades engineered to order against the feed assay. Output: palladium sponge and powder.
Purified rhodium (≥ 99.95%) — dissolved from the crude metal, then separated as an ammonium trisulfite complex and converted through ammonium chlororhodate and a rhodium ammine complex before hydrogen reduction. Rh ≥ 99.95%. Output: rhodium metal powder and sponge, or a purified rhodium compound where the buyer prefers salt form.
Iridium, ruthenium and osmium — recovered on request: iridium from the rhodium tail liquid as a hydroxide and then a refined metal, ruthenium by oxidative distillation of its tetroxide into hydrochloric acid and reduction to powder at >99.9%, and osmium only in a dedicated fully enclosed circuit because its tetroxide is highly toxic. Output: Ir / Ru / Os powder and salts.
Purified PGM compounds — where a buyer prefers chemical rather than metal form: chloroplatinic acid, ammonium chloroplatinate, palladium chloride, ammonium chloropalladate, chlororhodic acid, ammonium chlororhodate and rhodium ammine salts. Output: purified salts and standardised solutions to specification.
Gold and silver co-products — where the feed still carries Au and Ag, silver leaves as silver chloride for its own electrolytic circuit and gold is reduced out as powder. Output: gold powder ≥ 99.99% and silver chloride or silver metal.
Base-metal and support by-products — copper, nickel, iron, lead and zinc removed during conditioning are recovered by cementation, precipitation or electrowinning, and decontaminated catalyst support is routed to sale or disposal. Output: base-metal salts or cathode, and decontaminated support.
Recovered values from gas and effluent — condensate and scrubber liquor are returned to the process rather than discharged, and polish-water is recirculated to the rinse loop. Output: compliant off-gas, recirculated process water and dewatered residue.

Platinum Palladium Rhodium Refining Process Flow

The line runs as a purification ladder rather than a single pass: the feed is dissolved, cleaned, and then each metal is pushed through its own repeated-precipitation cycle until the assay says it has arrived. Platinum, palladium and rhodium are purified in dedicated vessels on their own chemistry, the verification loop sits in the middle of the flow rather than at the end of it, and the gas and effluent circuits run continuously alongside the metal chain.

Steps 1 — Feed Assay, Route Selection and Batch Planning. Incoming crude metal, salt, strip liquor or residue is weighed, sampled and assayed for platinum, palladium, rhodium, iridium, gold, silver and the main base metals, and the physical form is recorded. From that assay the batch route is written: which metal is being purified, at what solution strength, through how many precipitation cycles, and which of the parallel reactors will carry it. Output: a batch route sheet with the input assay and the target grade.

Steps 2 — Crude Metal Dissolution and Solution Make-Up. Crude platinum and palladium are dissolved in aqua regia; where the feed resists aqua regia, dissolution runs in hydrochloric acid with chlorine as the oxidant or with hydrogen peroxide. The solution is then boiled down to destroy excess nitric acid and re-taken into hydrochloric acid so that the metal sits as a clean chloride liquor at the strength the precipitation step needs. Crude rhodium cannot be opened by acid alone: it is dissolved by sodium bisulfate fusion followed by dilute sulfuric acid leaching, by medium-temperature chlorination roasting followed by dilute hydrochloric acid leaching, or by surface activation and aqua regia, and the resulting liquor is filtered clear. Output: clear single-metal chloride liquor at controlled concentration, and a dissolution residue routed back for retreatment.

Steps 3 — Impurity Removal and Solution Conditioning. Before any precipitation, the liquor is cleaned of what would otherwise contaminate the product: silver is dropped out as silver chloride, gold is removed by reduction where the feed is gold-bearing, silica and fine solids are filtered off, and organic carry-over from solvent extraction is stripped out. Acidity, oxidation state and metal concentration are then adjusted to the window the purification chemistry requires, because a platinum batch precipitated at the wrong acidity or a palladium batch oxidised with the wrong reagent will simply fail the assay two steps later. Output: conditioned single-metal liquor with a recorded analysis, plus filtrate and residue streams routed to their own circuits.

Steps 4 — Platinum Purification. Platinum is purified inside the fume hood in a heated, agitated reactor with a sealed mouth and a reflux condenser. The solution is adjusted to 50–80 g/L Pt, and ammonium chloride is added with stirring to the hot liquor so that yellow ammonium chloroplatinate crystallises out, leaving base-metal chlorides and the low-valent chloro-ammonium salts of gold, palladium and iridium in solution. Excess ammonium chloride is added until the free concentration reaches 5–10%, the batch is cooled, and the salt is filtered and washed with 5% ammonium chloride acidified to pH 1 so that the wash removes mother liquor without re-dissolving the product. A small sample is calcined and spectrographically analysed; if it is on specification the batch proceeds, and if it is not, the whole lot is calcined back to crude metal and re-dissolved in aqua regia, while the filtrate is treated with hydrazine hydrate to recover the platinum that stayed in solution as platinum black, which is then re-dissolved in hydrochloric acid with hydrogen peroxide and re-precipitated with ammonium chloride. After roughly three dissolution-and-precipitation cycles from a 90% crude platinum feed, the ammonium chloroplatinate reaches specification and is calcined at above 800 °C and hydrogen-reduced to sponge. Output: platinum sponge at ≥ 99.99%, with the off-specification loop returning metal to the head of the cycle rather than to the warehouse.

Steps 5 — Palladium Purification. Palladium is purified by the ammonium chloropalladate route combined with ammonia complexation. The chloride liquor is held at Pd(II) 40–50 g/L, oxidised with chlorine gas or hydrogen peroxide, and treated with 10–15% more ammonium chloride than the stoichiometric requirement, which precipitates dark red crystalline ammonium chloropalladate while base-metal impurities stay in solution. The first precipitate is not yet product: it is filtered, washed with 10% ammonium chloride, slurried in pure water and boiled until the precipitate dissolves, which reduces the hexachloro salt to soluble dark red ammonium chloropalladate; the solution is cooled, re-oxidised and re-precipitated, and the slurry-boil cycle is repeated two to three times, which is what actually strips the base metals. The batch then goes through ammonia complexation — heated to about 80 °C, complexed with ammonia liquor at a controlled pH 8–9 to form the soluble tetraammine palladium salt, filtered clear of insoluble impurities, slurried to about 80 g/L Pd, complexed again and acidified again for a further two to three cycles — which is what removes the other platinum-group metals. Both levers are used because they cover each other’s weakness: the precipitation route is strong against base metals but weak against other PGMs, and ammonia complexation is strong against other PGMs but lets copper and nickel through as soluble ammines. The purified compound is then reduced with hydrogen, hydrazine hydrate or formic acid and dried. Output: palladium sponge and powder at ≥ 99.99%.

Steps 6 — Rhodium Purification. Rhodium is purified in two distinct stages — pure rhodium compound first, pure rhodium metal afterwards — and the plant is operated on the rule that a rhodium solution or precipitate is never converted to metal until its purity has been confirmed. The clear sodium chlororhodate liquor at about 50 g/L Rh is adjusted with dilute alkali to pH 1–1.5, treated with a 25% ammonium sulfite solution at a volume ratio of about 1:0.75 and boiled with the pH controlled near 6.4, at which point rhodium precipitates as a milky-white ammonium trisulfite complex while iridium — which forms no comparable precipitate — remains in solution. The precipitate is filtered, washed with pure water and dissolved in boiling concentrated hydrochloric acid to ammonium chlororhodate, which is then purified further by ammonia complexation: treatment with ammonia precipitates a rhodium ammine chloride while iridium hydrolyses to insoluble hydroxide; the precipitate is washed with sodium chloride solution and the rhodium compound is re-dissolved in sodium hydroxide, leaving the iridium hydroxide to be filtered off. The rhodium solution is acidified, converted through the nitrate form, boiled to concentrate it and treated with hydrochloric acid to destroy residual nitric acid, giving a clean chlororhodic acid solution that is hydrogen-reduced to metal. A single ammonium sulfite pass separates most of the iridium but recovers only about 95% of the rhodium, so the rhodium-bearing filtrate and wash liquors are returned to the head of the purification circuit instead of being discarded, and the iridium stream is held for its own recovery. Output: rhodium metal powder at ≥ 99.95%, a pure rhodium compound where the market prefers salt form, and an iridium-bearing tail stream.

Steps 7 — Iridium, Ruthenium and Osmium Separation. Iridium recovered from the rhodium tail is precipitated as a hydroxide, washed and refined to metal. Ruthenium is separated by oxidative distillation: the ruthenium solution is stripped of free chlorine by heating with a little ethanol to hold the metal as a stable chloro complex, then re-oxidised so that residual osmium volatilises as its tetroxide into an alkali absorption system; the ruthenium is then distilled as ruthenium tetroxide under reduced pressure into hydrochloric acid, either after precipitation as ruthenium hydroxide and re-slurrying or directly from the concentrated liquor, until the outlet test shows the distillation is complete. The oxidant is added slowly and the temperature is held low through this stage, because ruthenium tetroxide is far less stable than osmium tetroxide and can disproportionate violently if it accumulates in a hot gas phase. The purified ruthenium liquor is precipitated with ammonium chloride, washed with ethanol, and reduced in a hydrogen furnace — dried at low temperature, slowly raised to 450–500 °C to decompose the ammonium salt and then to about 950 °C — to ruthenium powder of > 99.9%, which is moved straight into a sealed desiccator because the powder oxidises readily. Osmium is handled only in a dedicated, fully enclosed circuit with alkali absorption, because its tetroxide is acutely toxic. Output: iridium, ruthenium and osmium powder and salts, with no volatile PGM leaving the building.

Steps 8 — Fineness Verification and Purity Upgrade Loop. The purified salts and reduced metals are sampled and assayed before they are allowed to leave the circuit. Platinum, palladium and rhodium are checked by fire assay with cupellation, by ICP-OES for the main impurity set and by ICP-MS where trace levels matter, and the batch is compared against the target grade. A lot that meets specification is released to smelting and casting; a lot that does not is re-dissolved and taken back through precipitation and reduction, or calcined back to crude metal and re-started, rather than blended down or downgraded. Because the decision is made on an assay rather than on a colour, the plant can hold a 4N release standard batch after batch. Output: a released batch with a Certificate of Analysis, or a documented re-purification instruction.

Steps 9 — Melting, Casting, Granulation and Packaging. Purified sponge and powder are melted in induction furnaces under inert gas or vacuum and cast into bars, buttons or granules, or granulated under controlled conditions for buyers who feed metal into alloying or catalyst-making. Cast product is solidified in a vacuum or protective-atmosphere casting chamber so that the bar is free of voids, ripples and shrinkage, and sponge intended for catalyst and alloy makers is packed as produced. Output: cast bars, granules, buttons, sponge and powder in saleable packaging.

Steps 10 — Off-Gas Scrubbing and Effluent Polishing. Aqua regia dissolution and nitric-acid impurity removal produce the most aggressive off-gas in precious-metal refining, so the reactor mouth is sealed, vapour is condensed in a cold-water condenser and separated in a gas–liquid separator, and the metal-bearing condensate is returned to the batch. The remaining nitrogen oxide passes through a multi-stage absorption tower under negative pressure that is sized for an inlet load of the order of 30,000 mg/m³ — about 20,000 ppm in a normal batch — and holds the outlet below 150 ppm at 99.5% absorption efficiency, while also absorbing high concentrations of chlorine and sulfur dioxide; the absorption reagent converts the nitrogen oxide into nitrogen, carbon dioxide and water, so there is no secondary pollution to treat. Wastewater and bleed streams are segregated, neutralised in PPH neutralisation vessels, metal-polished and returned to the rinse loop. Output: compliant off-gas, recirculated process water, and dewatered residue.

The main chain runs vertically through dissolution and conditioning → platinum → palladium → rhodium → iridium, ruthenium and osmium → verification and the purity upgrade loop → melting and casting, with gas and effluent treatment running in parallel throughout. Side branches route the platinum filtrate to hydrazine recovery, the palladium mother liquor and wash liquors back to re-precipitation, the rhodium filtrate and wash water back to the head of the rhodium circuit, the iridium hydroxide to iridium refining, the ruthenium tetroxide distillate to acid absorption, silver chloride to the silver circuit, and reactor condensate and scrubber liquor back into the process.

1.Platinum Purification Chemistry in Detail

Platinum purification is built on two properties of the metal that make the chemistry unusually forgiving. In acid media platinum forms a sparingly soluble ammonium chloroplatinate that will not carry base metals or the low-valent chloro-ammonium salts of the other PGMs with it, and in alkaline media it forms a soluble hydroxo complex that separates it from metals whose hydroxides precipitate. The plant uses the first as the workhorse and the second, oxidative hydrolysis, as the polishing lever where a feed carries iridium or stubborn base metals that repeated precipitation alone will not shift.

Concentration window: solution adjusted to 50–80 g/L Pt before precipitation.
Precipitation: ammonium chloride added to the hot, stirred solution; excess carried to 5–10% free ammonium chloride.
Wash: 5% ammonium chloride acidified to pH 1, which removes mother liquor without dissolving product.
Cycles: about three dissolution-and-precipitation cycles from a 90% crude platinum feed reach specification.
Recovery of dissolved values: hydrazine hydrate reduces residual platinum to platinum black at room temperature; the black is re-dissolved in hydrochloric acid with hydrogen peroxide and re-precipitated.
Conversion to metal: calcination at above 800 °C, then hydrogen reduction to sponge.
Achievable grade: 99.9% to 99.999%, with 4N (99.99%) as the standard release grade and 5N (99.999%) available on suitable feed.

2. Palladium Purification Chemistry in Detail

Palladium offers two purification levers, and the plant runs both because neither is complete on its own. Ammonium chloropalladate precipitation rejects base metals well but tolerates other PGMs; ammonia complexation rejects other PGMs well but lets copper and nickel follow palladium into solution as soluble ammines. Running the two in series is what produces 4N palladium rather than merely clean palladium.

Oxidation: chlorine gas or hydrogen peroxide, to hold palladium in the hexavalent chloro form.
Precipitation: ammonium chloride at 10–15% above the stoichiometric requirement, giving dark red crystalline ammonium chloropalladate.
Wash and cycling: 10% ammonium chloride wash, then slurry in pure water and boil until the precipitate dissolves, which reduces the salt to soluble ammonium chloropalladate; re-oxidise, re-precipitate, repeat two to three times.
Ammonia complexation: heated to about 80 °C, ammonia liquor added to a controlled pH 8–9 to form the soluble tetraammine salt; slurry to about 80 g/L Pd; complex and acidify for a further two to three cycles.
Conversion to metal: hydrogen, hydrazine hydrate or formic acid reduction, then controlled drying.
Achievable grade: Pd ≥ 99.99% (4N) as standard, with higher grades engineered against the feed assay.

3. Rhodium Purification Chemistry in Detail

Rhodium is the hardest of the three, and the plant says so rather than pretending otherwise. Rhodium(III) chloro-complexes are kinetically stable, so the metal cannot be separated by the valence differences that work for platinum and palladium; the route depends entirely on ligand substitution — sulfite first, ammonia second — to build a rhodium compound whose solubility and behaviour differ from iridium’s. Crude rhodium metal must also be opened before any of that chemistry can start, and every available dissolution route needs high-temperature equipment and a long cycle.

Dissolution of crude rhodium: sodium bisulfate fusion with dilute sulfuric acid leaching; medium-temperature chlorination roasting with dilute hydrochloric acid leaching; surface activation followed by aqua regia; or electrochemical dissolution. Several passes may be needed for complete dissolution.
Operating rule: the resulting solution or precipitate is not converted to metal until its purity has been confirmed, and the plant produces rhodium compounds as finished product wherever the market wants salt rather than metal.
Sulfite separation: about 50 g/L Rh sodium chlororhodate, adjusted to pH 1–1.5, treated with 25% ammonium sulfite at a volume ratio of about 1:0.75, boiled at pH ≈ 6.4, giving a milky-white ammonium trisulfite precipitate while iridium stays in solution.
Conversion: the precipitate is washed with pure water and dissolved in boiling concentrated hydrochloric acid to ammonium chlororhodate.
Ammonia purification: ammonia complexation precipitates a rhodium ammine chloride while iridium hydrolyses to hydroxide; the precipitate is washed with sodium chloride solution, the rhodium compound is re-dissolved in sodium hydroxide, and the iridium hydroxide is filtered off.
Finishing: acidification, conversion through the nitrate form, boiling to concentrate and hydrochloric acid treatment to remove residual nitric acid, giving chlororhodic acid for hydrogen reduction.
Yield note: one ammonium sulfite pass separates most of the iridium but recovers only about 95% of the rhodium; the filtrate and wash liquors are returned to the circuit, and the iridium stream is recovered separately.
Achievable grade: Rh ≥ 99.95%.

Product Structure (Main Equipment)

The set is supplied as factory-assembled, piped and functionally tested modules. PGM purification batches are small, so the reaction train is deliberately compact and built inside a sealed fume hood, with the wetted path in borosilicate glass, titanium, glass-lined steel or anti-ageing PPH according to duty.

Sealed Reaction Fume Hood and Local Extraction — enclosed hood over the reaction train with local extraction, viewing access and a sealed reactor mouth for every vessel inside it, plus gas-detection interlocks. Function: containing acid mist and nitrogen oxide at source while keeping every reaction visible to the operator.
Feed Preparation, Weighing and Sampling Station — crusher or cutter for alloy and wire feed, mill and screen for powder and residue, and a weighing and sampling bench with XRF screening. Function: reducing feed to a uniform form and producing a representative assay sample before any acid is opened.
Borosilicate Glass and PP Reaction Bucket Train — borosilicate glass reactors and PP buckets in graduated sizes with stirring, heating mantles, sealed lids and reflux condensers. Function: running precipitation, complexation, slurry-and-boil reduction and re-dissolution where the operator must see the colour change and the precipitate form.
Titanium and Glass-Lined Dissolution Reactors — titanium and titanium-clad vessels for chloride liquors and aqua regia, and glass-lined (enamel) steel reactors for general acid service, all with agitation, controlled heating and vacuum connections. Function: dissolving crude platinum, palladium and rhodium feed under enclosed, heated, corrosion-safe conditions.
Rhodium Dissolution and Fusion Station — fusion furnace and leach vessel for sodium bisulfate fusion, plus a chlorination roasting and leaching set-up with acid-resistant trays. Function: opening crude rhodium metal, which no straight acid attack will dissolve.
Condensation and Gas–Liquid Separation Unit — cold-water circulation condenser, condensate receiver and gas–liquid separator on the reactor vent line with condensate return to the batch. Function: recovering the metal carried in vapour instead of losing it to the exhaust.
Reagent Preparation and Metering Station — graduated chemical tanks, metering and dosing pumps and PPH trays inside secondary containment for aqua regia, hydrochloric and nitric acid, ammonium chloride, ammonium sulfite, ammonia liquor, hydrogen peroxide, hydrazine hydrate, formic acid and alkali. Function: repeatable, precise reagent addition with reduced operator exposure.
Filtration, Vacuum Filter Plate and Washing Train — vacuum filter plates with porous plate and filter cloth, wheel and plate-and-frame filters with diaphragm pumps, wash-water receivers and vacuum draw-off piping. Function: separating precipitate from mother liquor and washing it clean, which is where a purification batch is won or lost.
Vacuum Liquid Lifting and Solution Transfer System — vacuum receivers, level-control piping, liquid-ring vacuum pump or centrifugal pump with level control tubes, and solution transfer lines. Function: moving high-value liquor by vacuum rather than pouring, so nothing is spilled, decanted by hand or left behind.
Glass Elevated (High-Level) Storage Tanks and Receivers — transparent borosilicate elevated tanks and receivers with sight levels, replacing opaque vessels wherever the duty allows. Function: visual level control, complete clean-out and minimum metal held up on tank walls.
Precipitation and Complexation Reactor Set — dedicated temperature-controlled reactors with dosing and agitation for platinum, palladium and rhodium precipitation, slurry-boil cycling, ammonia complexation at pH 8–9 and sulfite complexation at a controlled pH 1–1.5 rising to 6.4. Function: carrying each metal through its own repeated-precipitation cycle without cross-contaminating the other two.
Solvent Extraction and Ion-Exchange Skid — mixer-settler banks and centrifugal extractors for phosphine oxide, amine and thiol extractants, plus ion-exchange and molecular-recognition columns with elution and regeneration circuits. Function: a second separation lever for feeds with unusual iridium, ruthenium or base-metal loads, and a concentrator for dilute PGM streams.
Calcination and Hydrogen Reduction Furnace Set — calcination furnace for ammonium salts operating above 800 °C, hydrogen reduction furnace with a controlled temperature programme from low-temperature drying through 450–500 °C ammonium salt decomposition to about 950 °C calcination-reduction, and controlled drying ovens. Function: converting purified PGM salts to metal sponge and powder at controlled temperature and atmosphere.
Nitrogen Oxide and Acid Gas Treatment System — multi-stage absorption tower in high-performance PP with anti-ageing additives, gas–liquid separators, circulation pumps and receivers, and alkali neutralisation under negative pressure, sized for inlet nitrogen oxide of the order of 30,000 mg/m³ and absorbing chlorine and sulfur dioxide as well. Function: reducing nitrogen oxide below 150 ppm at 99.5% absorption efficiency without generating a secondary waste stream.
Wastewater Neutralisation and Polishing Unit — PPH neutralisation vessels from 0.05 m³ to 5 m³ rated for atmospheric to −0.1 MPa and −10 °C to 80 °C, settling tank, sludge filter press and polish-water loop with metal analysis. Function: compliant discharge and recirculation of process water.
Melting and Casting Unit — induction melting furnaces under inert gas or vacuum, vacuum ingot casting machine with a pressurised inert-gas chamber, granulator, and ingot moulds. Function: producing void-free bars, buttons, granules and granulated product from purified metal.
Assay, Quality-Control and Documentation Station — XRF analyser, fire-assay furnace with cupellation equipment, sample preparation bench, potentiometric titration and ICP-OES, with ICP-MS for trace work. Function: input control, the fineness check that drives the purity upgrade loop, and the Certificate of Analysis for every batch.
PLC Automation and Control Cabinet — PLC with touch-screen HMI covering dosing, temperature, pH, vacuum, scrubbing and rectifier control, with parameter logging, alarms, interlocks and batch traceability. Function: repeatable operation and a defensible metal-accounting record.
Safety and Workplace Package — fume hoods, local extraction, acid-proof flooring and matting, secondary containment, eyewash and safety shower, gas detection and operator protective equipment. Function: operator protection and compliance with workplace chemical-handling rules.

Product Features

Built for metal-end purity, and says so. The line is designed to raise the fineness of finished Pt, Pd and Rh to 4N and 5N, which is a different job from solution-end polishing of raffinate. Buyers comparing quotations can see which of the two jobs a supplier is actually quoting.
A separate purification chemistry for each metal. Platinum on ammonium chloride repeated precipitation and oxidative hydrolysis, palladium on ammonium chloropalladate cycling plus ammonia complexation, rhodium on sodium bisulfate dissolution plus ammonium sulfite and ammonia ligand substitution. Not one generic acid bath applied to three different metals.
Runs inside a sealed fume hood, at bench scale by design. PGM purification batches are small and extremely high in value, so the reaction train is enclosed, reactions run in buckets and glassware where the operator can watch them, and separation happens in filters rather than by decanting.
Vacuum liquid lifting instead of pouring. Solution moves by vacuum, which removes the single most common cause of metal loss in a small refinery — a hand-poured decant that spills, splashes or leaves product behind.
Transparent glassware as a process instrument. Colour change, precipitate formation and solution level are read directly through borosilicate glass and transparent elevated tanks, so the operator decides the next step from what he can see and the vessels clean out completely.
Verification loop wired into the flow. A small sample is calcined and assayed mid-batch; an off-spec lot is calcined back to crude metal and re-dissolved rather than blended down or shipped as a downgrade.
Rhodium handled honestly, with its yield stated. One ammonium sulfite pass separates most of the iridium but recovers about 95% of the rhodium; that figure is published rather than buried, the rhodium-bearing filtrate is returned to the circuit, and the iridium stream is refined separately instead of contaminating the rhodium product.
Crude rhodium dissolution capability included. Sodium bisulfate fusion, chlorination roasting, activation-plus-aqua-regia and electrochemical dissolution are all part of the package, because rhodium metal cannot be opened by acid alone.
Chlorine-free of cyanide, and reagent-thrifty. The route uses aqua regia, hydrochloric and nitric acid, chlorine or hydrogen peroxide, ammonium chloride, ammonium sulfite, ammonia liquor, hydrazine hydrate, formic acid and hydrogen — no cyanide salt anywhere in the flow.
Materials matched to duty. Borosilicate glass, titanium and titanium-clad, glass-lined (enamel) steel and anti-ageing PPH, each used where it belongs rather than one material everywhere; glass-lined vessels are applied with their genuine service limits respected, including fluorides, hot concentrated phosphoric acid and hot alkaline duty.
High-concentration nitrogen oxide handled in-house. A sealed reactor mouth, condenser, gas–liquid separator and multi-stage negative-pressure absorption tower hold the outlet below 150 ppm from an inlet of the order of 30,000 mg/m³, and also absorb chlorine and sulfur dioxide.
Consumable-friendly chemistry. The absorption reagent degrades to nitrogen, carbon dioxide and water rather than to a secondary pollutant, and the reagent is cheap and readily available, which is why the running cost of the package stays low.
Low capital and low running cost, deliberately. The design brief is a compact, man-portable-scale train that a mid-size recycler can own, run and maintain, rather than a large hall full of oversized vessels.
Batch accountability. Weighing, sampling, assay and re-purification decisions are tied to a batch record, and every consignment is released against a Certificate of Analysis from fire assay and ICP-OES with ICP-MS confirmation.
Modular and scalable. The same chemistry and the same verification discipline run from a bench and pilot set to an industrial purification plant; capacity is added by duplicating reactor, filtration and treatment trains rather than by redesigning the process.

Technical Parameters & Specifications

Values below describe the standard process envelope and product outcomes. Throughput, footprint, power and utility figures are engineered to each client’s feed assay, target metals, batch frequency and site conditions, and are confirmed at design review rather than published as a fixed number.

Parameter	Specification
Product	Platinum Palladium Rhodium Purification Equipment (PGM metal-end purification and purity upgrading line)
Metals purified	Platinum (Pt) · Palladium (Pd) · Rhodium (Rh); iridium (Ir), ruthenium (Ru) and osmium (Os) on request
Purification scope	Metal-end purity upgrade of separated PGM feed; solution-end raffinate polishing supplied as a separate module
Recommended feed	Crude PGM metal above about 90% assay; PGM salts, strip liquor, ion-exchange eluate or refinery concentrate of equivalent metal content
Standard release grades	Pt ≥ 99.99% (4N) · Pd ≥ 99.99% (4N) · Rh ≥ 99.95%
Highest grade available	Pt up to 99.999% (5N) on suitable feed and repeated precipitation cycles; Pd and Rh higher grades engineered to order against the feed assay
Overall purification recovery	Pt ≥ 99% · Pd ≥ 99%; Rh approximately 95% in a single ammonium sulfite pass, with the rhodium-bearing filtrate and wash liquors returned to the head of the circuit
Platinum process window	Solution at 50–80 g/L Pt · ammonium chloride excess to 5–10% free NH₄Cl · wash with 5% NH₄Cl acidified to pH 1 · about 3 dissolution-and-precipitation cycles from 90% crude platinum · calcination above 800 °C · hydrogen reduction to sponge
Platinum alternative route	Oxidative hydrolysis in alkaline media, giving a soluble hydroxo complex that separates platinum from metals whose hydroxides precipitate
Palladium process window	Solution at Pd(II) 40–50 g/L · oxidation with chlorine or hydrogen peroxide · ammonium chloride at +10–15% over stoichiometry · 10% NH₄Cl wash · slurry-and-boil reduction cycle repeated 2–3 times · ammonia complexation at about 80 °C and pH 8–9 · slurry to about 80 g/L Pd · complexation and acidification repeated 2–3 times
Rhodium process window	Sodium chlororhodate at about 50 g/L Rh · dilute alkali to pH 1–1.5 · 25% ammonium sulfite at volume ratio about 1:0.75 · boil at pH ≈ 6.4 to precipitate the ammonium trisulfite complex · ammonia complexation to a rhodium ammine chloride · sodium hydroxide re-dissolution with iridium hydroxide removal
Crude rhodium dissolution	Sodium bisulfate fusion with dilute sulfuric acid leaching · medium-temperature chlorination roasting with dilute hydrochloric acid leaching · surface activation followed by aqua regia · electrochemical dissolution
Ruthenium process window	Oxidative distillation of ruthenium tetroxide into hydrochloric acid · ammonium chloride precipitation · hydrogen reduction with low-temperature drying, 450–500 °C salt decomposition and about 950 °C calcination-reduction · product > 99.9% Ru
Dissolution chemistry	Aqua regia (approximately 3:1 HCl : HNO₃) · hydrochloric acid with chlorine as oxidant · hydrochloric acid with hydrogen peroxide · hydrogen-peroxide oxidation for palladium · sodium bisulfate fusion for rhodium
Separation technologies	Repeated ammonium salt precipitation · oxidative hydrolysis · ammine complexation and acidification cycling · ammonium sulfite and ammonia ligand substitution · solvent extraction and centrifugal extraction · ion-exchange and molecular-recognition columns · cementation
Wetted materials	Borosilicate glass · titanium and titanium-clad · glass-lined (enamel) steel · anti-ageing PP / PPH · stainless steel where duty allows
Glass-lined service limits	Glass lining fired at about 900 °C; not for fluoride-bearing media, for phosphoric acid above 30% concentration and 180 °C, for alkaline media above pH 12 at 80 °C, or for alternating acid–alkali duty; thermal shock limits 110 °C cold / 120 °C hot
Neutralisation vessel specification	PPH construction, 0.05 m³ to 5 m³, operating pressure atmospheric to ≤ −0.1 MPa, operating temperature −10 °C to 80 °C, vertical or horizontal configuration
Reaction temperature range	Ambient to about 90–100 °C in the chemical section, with calcination, reduction and melting at higher temperature in their dedicated furnaces
Solution transfer and filtration	Vacuum liquid lifting · vacuum filter plates and wheel filters with diaphragm pumps · filter presses · transparent glass elevated tanks and receivers
Off-gas inlet nitrogen oxide	Of the order of 30,000 mg/m³ (about 20,000 ppm in a normal batch)
Treated nitrogen oxide	Below 150 ppm, within discharge standard
Scrubber absorption efficiency	≥ 99.5% for nitrogen oxide; also absorbs high-concentration chlorine and sulfur dioxide
Scrubber construction	High-performance polypropylene with anti-ageing additive; negative-pressure absorption; reagent converted to nitrogen, carbon dioxide and water with no secondary pollution
Wastewater treatment	Segregated collection, neutralisation, metal precipitation and polishing; polish water recirculated to the rinse loop
Casting	Vacuum ingot casting machine casting 1–2 kg bars and 4 × 1 kg or 1 × 12.5 kg configurations at approximately 15 minutes per cycle, under nitrogen or argon, with a 63 m³/hour vacuum pump and 2 kW induction heating on 380 V; granulator and ingot moulds for buttons and granules
Assay and quality control	XRF input screening · fire assay with cupellation · ICP-OES impurity analysis · ICP-MS trace verification · Certificate of Analysis per batch
Automation	PLC with touch-screen HMI; dosing, temperature, pH, vacuum and scrubbing control; parameter logging, alarms and interlocks
Configuration scale	Laboratory bench · pilot · industrial turnkey, with the same chemistry and verification discipline at every scale
Standards	CE; EPA and EU emission and discharge limits; cyanide-free process route

Technical Advantages

The purity claim is split by metal and by verification method. Most suppliers publish one generic purity figure, or none at all. This line publishes Pt ≥ 99.99%, Pd ≥ 99.99% and Rh ≥ 99.95% separately, states the 5N (99.999%) ceiling for platinum, and names the assay behind each release — fire assay, ICP-OES and ICP-MS. A buyer comparing quotations can see exactly what is being promised and how it will be proved.
Rhodium recovery is stated rather than implied. One ammonium sulfite pass separates most of the iridium but recovers about 95% of the rhodium. Publishing that number, returning the rhodium-bearing filtrate to the circuit and refining the iridium stream separately is what separates an honest rhodium route from one that quietly reports iridium contamination as yield.
Crude rhodium can actually be opened. Rhodium metal resists acid attack, and a purification line that cannot dissolve its own feed is a laboratory exercise. Fusion, chlorination roasting, activation-plus-aqua-regia and electrochemical dissolution are all part of the package, with the high-temperature equipment and the long cycle that go with them.
The purity upgrade loop is a process step, not an afterthought. Mid-batch calcination and assay sampling mean an off-specification lot is caught inside the plant and returned to the head of the circuit, instead of being detected at the customer’s assay office after shipment.
Two separation levers for palladium, deliberately in series. Ammonium chloropalladate precipitation rejects base metals but tolerates other PGMs; ammonia complexation rejects other PGMs but lets copper and nickel follow as soluble ammines. Running both, with 2–3 cycles each, is what produces 4N palladium rather than palladium that merely looks clean.
Metal loss to the exhaust is recovered, not vented. Sealing the reactor mouth and condensing the vapour returns the metal carried in the condensate to the batch. In a plant where a single batch can be worth more than the machinery, this one detail pays for itself first.
High-concentration nitrogen oxide is handled at design stage. Dissolving crude PGM in aqua regia, or destroying nitric acid in a palladium solution, generates nitrogen oxide of the order of 30,000 mg/m³. The negative-pressure multi-stage tower is sized for that load, holds the outlet below 150 ppm at 99.5% efficiency, absorbs chlorine and sulfur dioxide at the same time, and consumes a reagent that breaks down to nitrogen, carbon dioxide and water.
Visibility and cleanability are treated as recovery tools. Transparent glassware, transparent elevated tanks and vacuum filter plates let the operator read the reaction and the filtration directly, and they clean out completely. Metal that stays on a tank wall or in a filter cloth is metal that never reaches the Certificate of Analysis.
Vacuum liquid lifting removes the human error term. Hand decanting is where small refineries lose metal and where operators are exposed to acid. Moving solution by vacuum addresses both at once.
Corrosion engineering matched to each duty. Aqua regia, chloride liquor, ammonium sulfite, ammonia liquor and alkali attack materials differently; using borosilicate glass, titanium, glass-lined steel and anti-ageing PPH where each belongs extends equipment life and prevents the trace contamination that a wrongly chosen material introduces into a 4N product.
Low capital and low operating cost by design intent. A compact hood-based train with cheap, readily available reagents, a small footprint and a cyanide-free reagent list is cheaper to build, to permit and to run than a hall-scale refinery — and it produces the same four-nines metal.
By-products instead of disposal costs. Base metals from conditioning, gold and silver where present, iridium and ruthenium from the tail streams, and decontaminated catalyst support all leave as recoverable or saleable material rather than as tipping fees.
Batch traceability on a product whose value exceeds the plant. Weighing, sampling, assay and re-purification decisions sit inside the control system, so every batch carries an input assay, a process record and an output Certificate of Analysis — the documentation that buyers, banks and auditors ask for.
Turnkey single-point accountability. One contractor owns assay, test work, process design, equipment, assembly, commissioning and operator training, which removes the integration risk of assembling a purification plant from several vendors’ modules.

Service Process

YuSai delivers a platinum palladium rhodium purification package as a full turnkey project, from feed characterisation and bench test work to a running, assay-verified purification plant — including projects where the client’s feed, target grades and site are all still open at the enquiry stage.

Steps 1 — Feed Characterisation and Purification Consultation. Send representative samples of your crude PGM metal, salt, strip liquor or residue. Our metallurgical team assays for platinum, palladium, rhodium, iridium, gold, silver and the main base metals, identifies which impurities are actually limiting the grade, and proposes the purification route, the number of precipitation cycles and the achievable fineness. Output: assay report and preliminary purification route proposal.

Steps 2 — Laboratory Test Work and Route Design. Bench campaigns confirm the dissolution conditions for your specific feed, the precipitation and complexation windows, reagent consumption, the rhodium sulfite pass and its yield, and the expected recovery — and convert them into a mass balance, flowsheet, equipment list, vessel sizing, utility schedule and plant layout against your throughput, site and local emission and discharge rules. Output: test report, process design package and firm quotation.

Steps 3 — Detailed Engineering and Manufacturing. Reaction fume hood, dissolution reactors, glassware and bucket train, filtration and vacuum filter plates, vacuum liquid lifting system, precipitation and complexation reactors, solvent extraction and ion-exchange skid where required, absorption tower, neutralisation unit, calcination and hydrogen reduction furnaces, casting machine and control cabinet are fabricated, pre-assembled and piped. Output: engineered, skid-mounted modules.

Steps 4 — Factory Assembly, Testing and Acceptance. Each module is functionally tested and the whole train is trial-run — where possible on your own material — with the client invited to attend the factory acceptance test before shipment. Output: FAT-approved, pre-commissioned modules.

Steps 5 — Shipping, Installation and Commissioning. We supervise the civil interface, erection, piping, ductwork and electrical tie-in, then run a commissioning campaign on your feed until the contracted purity and recovery are demonstrated, the fineness check is repeatable, and the nitrogen-oxide outlet is verified against your local limit. Output: a producing purification plant at contracted performance.

Steps 6 — Operator Training and Handover. On-site training covers safe aqua regia and chlorination working, reagent metering, precipitation and complexation control, the slurry-boil and ammonia complexation cycles, rhodium sulfite operation, off-gas and effluent operation, emergency procedures and assay quality control, supported by Standard Operating Procedures and a full handover dossier. Output: trained crew and complete documentation.

Steps 7 — Process Optimisation and Ongoing Support. Remote troubleshooting, reagent and consumable supply, periodic performance audits, purity-upgrade reviews as feed changes, and recovery or capacity upgrade paths keep the plant at target over its service life. Output: sustained performance and spare-part continuity.

Warranty & After-Sales Service

Standard warranty. Twelve (12) months from commissioning, or eighteen (18) months from shipment, whichever comes first, covering structural, mechanical, electrical, control, furnace and scrubbing equipment against defects in material and workmanship.
What the warranty covers. Replacement of defective components, repair or exchange of main-process equipment, and free remote technical guidance throughout the warranty period. Consumables such as reagents, filter cloth, glassware, electrodes, resin and packing materials, and damage caused by misuse, unauthorised modification or operation outside the agreed feed and process envelope, are excluded.
Guaranteed performance. We warrant that, when fed material inside the agreed assay and batch envelope and operated to the supplied SOP, the line meets the contracted Pt, Pd and Rh purity and recovery figures, verified at commissioning by fire assay and ICP-OES.
Response commitment. Guaranteed remote response within 24 hours, on-site engineer dispatch and hotline support for breakdowns affecting production, and expedited supply of critical spares.
Spare parts and consumables. Genuine spares, glassware sets, metering pumps, filter cloth and plates, tower packing, furnace elements, refractory and reagent ranges are held as a stocking range to minimise downtime.
Commissioning and start-up support. Supervised installation, commissioning on the customer’s own feed, performance verification against contract, off-gas outlet verification and an operator competence sign-off before handover.
Assay and documentation support. Assistance in setting up the client’s own input and output assay routine — sampling, fire assay, ICP-OES and ICP-MS practice — so that the purity figure the plant produces can be reproduced and defended in front of a buyer.
Lifetime technical support. Free access to our engineering team for process questions after warranty expiry, plus optional retrofit, capacity-upgrade, recovery-improvement and reagent-optimisation services.
Documentation. Full operating, maintenance and safety manuals, electrical drawings, P&ID, tower and furnace documentation, spare-parts catalogue, SOPs and training material accompany every line.
Compliance support. Assistance with local emission, effluent and chemical-storage permitting documentation, and with the assay and product-certification records that buyers and authorities require.

Frequently Asked Questions

Q1. What is platinum palladium rhodium purification equipment?
Platinum palladium rhodium purification equipment is a metal-end purification plant that takes already-separated platinum-group metal — crude metal above about 90% assay, PGM salts, strip liquor or refinery concentrate — and upgrades it to a saleable fineness through repeated dissolution and re-precipitation chemistry, controlled calcination and hydrogen reduction, with every batch verified by assay. It delivers Pt ≥ 99.99%, Pd ≥ 99.99% and Rh ≥ 99.95% as standard release grades, with platinum available up to 99.999% (5N), and it treats the nitrogen-oxide off-gas that PGM dissolution generates inside the same package.

Q2. What does “purification” mean in this system — is it the same as refining?
In this system purification means metal-end purity: raising the fineness of the finished platinum, palladium and rhodium themselves. It is not solution-end polishing, which is the separate job of taking raffinate wash water and bleed streams from ppm down to ppb with membranes, ion-exchange resin and carbon. Both jobs exist in a refinery and both can be supplied, but they use different equipment, and this page describes the metal-end plant. Refining, in the wider sense, is the combined flow of dissolution, separation and purification; purification is the last and most valuable part of it.

Q3. Why is rhodium so much harder to purify than platinum or palladium?
Because rhodium cannot be separated by valence chemistry. Rhodium(III) chloro-complexes are kinetically stable, so the trick that works on platinum and palladium — forming a compound that base metals cannot form — does not work on rhodium. Its purification depends on changing the ligands: sodium sulfite is used to build an ammonium trisulfite complex that precipitates rhodium while iridium stays in solution, and ammonia is then used to build a rhodium ammine chloride while iridium hydrolyses to hydroxide. A single sulfite pass separates most of the iridium but recovers only about 95% of the rhodium, which is why rhodium purification is run in two stages and why the plant never converts a rhodium solution or precipitate to metal until its purity has been confirmed.

Q4. Why does crude rhodium metal need special dissolution equipment?
Rhodium metal will not open in acid alone, so the plant includes dissolution routes built for it: sodium bisulfate fusion followed by dilute sulfuric acid leaching, medium-temperature chlorination roasting followed by dilute hydrochloric acid leaching, surface activation followed by aqua regia, or electrochemical dissolution. All of them need high-temperature equipment and a longer cycle, and several passes may be required for complete dissolution.

Q5. How many times does a batch have to be re-precipitated to reach 4N?
For platinum, roughly three dissolution-and-precipitation cycles from a 90% crude feed reach specification, with the exact number set by the feed; the batch is sampled, calcined and assayed between cycles. For palladium, the slurry-and-boil reduction cycle runs two to three times, followed by ammonia complexation and acidification for a further two to three cycles. For rhodium, one ammonium sulfite pass plus the ammonia purification stage is the normal route. The plant is operated on assay results, not on a fixed count.

Q6. What purity can the equipment actually achieve, and how is it proved?
Standard release grades are Pt ≥ 99.99% (4N), Pd ≥ 99.99% (4N) and Rh ≥ 99.95%, with platinum up to 99.999% (5N) on suitable feed and repeated precipitation cycles. Purity is established by fire assay with cupellation, by ICP-OES impurity analysis and by ICP-MS where trace levels matter, and every batch is released against a Certificate of Analysis. The grade is confirmed on your own material during test work and verified again at commissioning.

Q7. What is the difference between 2N5, 4N and 5N in practice?
The nines describe how much is not the metal. 2N5 (99.95%) is the commercial grade and is fine for many alloying and catalyst uses. 4N (99.99%) is the standard release grade here, and it is what a buyer needs when residual base metals or the neighbouring platinum-group metals would change the behaviour of the final product. 5N (99.999%) is the ultra-fine grade, verified at trace level by ICP-MS, and it is offered for platinum; palladium and rhodium can be specified higher than the standard grades against a particular feed, and we will say so honestly if your feed will not support it.

Q8. Some suppliers quote fineness as 999.5/1000. How does that compare?
Fineness and purity describe the same thing in different language. 999.5/1000 equals 99.95%, which is commercial grade by the naming convention used above. European suppliers still quote fineness, particularly for platinum and palladium plants, so when you compare quotations it is worth converting every figure to the same unit before comparing price.

Q9. What feed grade does the plant need?
Purification works best on a crude PGM metal above about 90% assay, or a salt, strip liquor or eluate carrying equivalent metal content. Leaner material — a mixed PGM concentrate, a smelter matte, a leach residue — belongs upstream, where the metal is concentrated and separated first. During test work we will tell you where your material sits and whether pre-concentration or separation needs to be added ahead of purification.

Q10. Does the capacity figure mean per batch or per day?
Per batch, unless it is written otherwise — and this is worth pinning down with any supplier, because the industry is careless about it. PGM purification is a batch process: a batch is the quantity of metal charged into one reactor train, the batch time is the time from charging to released metal, and the daily or monthly throughput follows from how many batches run in parallel and how many shifts you operate. On this line, receiving capacity is quoted as kg per batch, as batches per day, and as kg per month at the same time, and the batch matrix is fixed at design review against your feed and your working pattern. Bench, pilot and industrial configurations all use the same chemistry.

Q11. How long does a purification batch take?
Batch time is dominated by the number of precipitation cycles and by the furnace schedule, not by any single reaction. Dissolution is a matter of hours; each precipitation, slurry-boil, filtration and wash cycle is short but sequential; ammonia complexation and acidification add a further cycle or two for palladium; calcination and hydrogen reduction run on their own temperature programme from drying through 450–500 °C salt decomposition to about 950 °C where a ruthenium or high-purity programme calls for it, with platinum salts calcined at above 800 °C. Assaying between cycles and at release is the other fixed time cost. The practical answer is that the plant is sized as a batch train with parallel reactors so that the weekly metal output matches your expectation, and the batch matrix is agreed at design review.

Q12. How is the nitrogen-oxide gas from PGM purification treated?
Dissolving crude PGM in aqua regia, and destroying nitric acid in a palladium solution, produce the most concentrated nitrogen-oxide off-gas in precious-metal refining — of the order of 30,000 mg/m³, about 20,000 ppm in a normal batch. The reactor mouth is sealed and fume-hooded, vapour passes through a cold-water condenser and gas–liquid separator so that the metal-bearing condensate returns to the batch, and the gas then enters a multi-stage absorption tower under negative pressure. The outlet is held below 150 ppm at 99.5% absorption efficiency. The same tower handles high concentrations of chlorine and sulfur dioxide, the construction is high-performance polypropylene with an anti-ageing additive, and the absorption reagent is converted to nitrogen, carbon dioxide and water — there is no secondary pollutant to deal with afterwards.

Q13. Does the process use cyanide?
No. The standard route uses aqua regia, hydrochloric and nitric acid, chlorine gas or hydrogen peroxide as oxidant, ammonium chloride, ammonium sulfite, ammonia liquor, hydrazine hydrate, formic acid and hydrogen. No cyanide salt is used at any stage, which keeps the plant out of the most heavily regulated reagent class and simplifies both permitting and workplace safety.

Q14. What materials of construction are used, and why does it matter?
Borosilicate glass, titanium and titanium-clad, glass-lined (enamel) steel, anti-ageing PP / PPH and stainless steel where duty allows, selected against the chemistry of each stage. Corrosion resistance is only part of the reason: transparent glassware and glass elevated tanks let the operator read colour change, solution level and precipitate formation directly, and they clean out completely, so residual metal held on equipment surfaces is minimised. Glass-lined vessels are used within their genuine limits — no fluoride-bearing media, no phosphoric acid above 30% at 180 °C, no alkaline media above pH 12 at 80 °C, no alternating acid-alkali duty, and slow heating and cooling within the 110 °C cold / 120 °C hot thermal-shock limits.

Q15. Should we purify in-house or sell our PGM fraction to a refiner?
In-house purification captures the full margin between a mixed PGM fraction and three certified metals, removes third-party refining charges, settlement delays and assay disputes, shortens the cash cycle and puts your own assay and product certification in your hands. It also turns previously marginal material into feed worth processing, because a batch no longer has to justify an international shipment. The economic case is normally settled by a test-work mass balance on your own material — which is the first thing we do.

Q16. Is the plant suitable for small volumes, or do we need a large refinery?
It is designed for exactly the situation where PGM purification volumes are small: a batch train inside a sealed fume hood, with reactions in buckets and glassware, filtration in vacuum filter plates and solution moved by vacuum lifting. That configuration keeps capital cost and running cost low while still delivering 4N and 5N metal. Bench, pilot and industrial configurations are available, and capacity is added by duplicating reactor and filtration trains rather than by rebuilding the chemistry.

Q17. What information is needed for a quotation?
A representative sample or assay of your feed giving platinum, palladium, rhodium, iridium and the main base metals; the material type and physical form, including whether the metal is in crude metallic, salt, solution or supported-catalyst form; the target grade for each metal; the batch size and how often you expect to run; the products and forms you want to sell; available floor area, headroom and utilities; and your local air-emission, wastewater and chemical-storage requirements. A sample and an assay are what let us confirm the route and commit to performance figures.

Q18. What warranty, installation and support are included?
A standard 12-month warranty from commissioning, or 18 months from shipment, whichever comes first, covering material and workmanship defects with defective-part replacement and free remote support, backed by a guaranteed-performance clause confirming the contracted purity and recovery at commissioning. Turnkey delivery includes supervised installation, commissioning on your own feed, off-gas outlet verification, on-site operator training with full SOPs, help setting up your own assay routine, a 24-hour remote response commitment, stocked spares and consumables, and lifetime technical support after warranty expiry.

Platinum Palladium Rhodium Purification Equipment

Product Overview

Application Scenarios

Applicable Raw Materials

Output Products

Platinum Palladium Rhodium Refining Process Flow

1.Platinum Purification Chemistry in Detail

2. Palladium Purification Chemistry in Detail

3. Rhodium Purification Chemistry in Detail

Product Structure (Main Equipment)

Product Features

Technical Parameters & Specifications

Technical Advantages

Service Process

Warranty & After-Sales Service

Frequently Asked Questions

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