RU2742994C1 - Method for selective extraction of rhodium rh, ruthenium ru and iridium ir from hydrochloric acid solutions of chlorine complexes of platinum pt (iv), palladium pd (ii), gold au (iii), silver ag (i), rhodium rh (iii), ruthenium ru (iv) and iridium ir (iv) - Google Patents

Abstract

FIELD: metallurgy.SUBSTANCE: invention relates to hydrometallurgy of platinum metals. Selective release of rhodium, ruthenium and iridium is carried out from a hydrochloric acid solution containing chlorine complexes of platinum Pt (IV), palladium Pd (II), gold Au (III), silver Ag (I), rhodium Rh (III), ruthenium Ru (IV), iridium Ir (IV). Solution is treated with carbon monoxide CO at atmospheric pressure, intensive stirring and heating with subsequent filtration. Hydrochloric acid solution is used at HCl content of 1.5–3 mol/l. After filtration there is obtained a precipitate containing Pt, Pd, Au, Ag, and a filtrate containing Rh, Ru, Ir in form of carbonyl chloride complexes Rh(I)-Rh(CO)2Cl2-, Ru(II)-Ru(CO)2Cl4-2and Ir(I)-Ir(CO)2Cl2-.Obtained filtrate is neutralized to HCl = 2 mol/l. Then Rh, Ru and Ir are sequentially separated from the filtrate by varying acidity of the solution. Rhodium is separated from solution at temperature 95 °C and pH 2 for 6 hours to obtain a filtrate containing ruthenium and iridium, and ruthenium is separated at temperature 95 °C and pH 5 for 6 hours. Filtrate residue containing Ir is treated with chlorine to an oxidative potential of 850 mV to form a solution of the chloro-complex Ir (IV) - [IrCl6]-2, into which NH4Cl is added and precipitated (NH4)2[IrCl6]. Obtained residue is calcined to obtain Ir.EFFECT: method increases degree of selectivity of extraction of rhodium, ruthenium and iridium from solution of noble metals with high degree of purity.1 cl, 4 tbl, 10 ex

Description

The invention relates to the hydrometallurgy of platinum metals. Such alloys are used as catalysts in the conversion of ammonia. In addition, such systems are formed as a result of the process of capturing platinoids at the capture devices after the ammonia conversion apparatus.

Extractive separation of platinum metals from solutions of their chloro complexes is also used, followed by the separation of the corresponding metal from their salts by calcination or electrochemical reduction. (Metallurgy of noble metals. Edited by LV Chugaev, M :, "Metallurgy", 1987, p. 432.)

The known "Method of purification of technical salt of ammonium hexachloroplatinate", including the transfer of platinum into solution and precipitation of pure salt, characterized in that the original technical salt is dissolved in an aqueous pulp by treatment with hydrazine at pH 1-2 and a temperature of 89-90 ° C, and the precipitation is pure salts are carried out by oxidative treatment of the solution with chlorine to a potential of 550-600 mV.

Auth. wit. USSR No. 1408738, IPC: C01G 55/00 dated 06.11.85

The known "Method for extracting platinum metals from solutions of refining production", including sorption from chloride solutions, characterized in that the sorption is carried out from chloride solutions in a dynamic mode using a weakly basic polycondensation anion exchanger with a matrix based on epoxy polyamine as a sorbent, then it is carried out by destruction of saturated anion exchanger by treatment with concentrated nitric acid and the resulting nitric acid solution containing platinum metals is sent to refining.

RF patent for invention №2188247, IPC: С22В 11/00; publ. 2002.08.27

Known "A method of obtaining refined palladium from chloride platinum-palladium solutions, including the deposition of a platinum salt with a solution of ammonium chloride, filtration of the precipitate, refining of palladium, characterized in that the platinum-palladium solution before the deposition of the platinum salt is treated with a solution of sodium chlorate to a redox potential of 800-900 mV when heated to 70-90 ° C.

RF patent for invention №2194085, IPC: С22В 11/00; publ. 2002.12.10

The known "Method of processing solutions-middlings of the refining production of platinum group metals", including the precipitation of palladium from a solution of tetraamminepalladochloride in the form of palladosammine (PZA) with hydrochloric acid, the precipitation of rhodium from a solution of its sodium hexanitrite with ammonium chloride in the form of ammonium-sodium rhodite separation (ANG hexanitol) sediments PZA and ANG rhodium by filtration, additional extraction of precious metals from mother liquors of PGM refining by cementation methods with non-noble elements, characterized in that the mother liquor from precipitation of palladosammine is neutralized with ammonia until the pH reaches 1 to 5, the neutralized solution is filtered from the precipitate and used as ammonium chloride during the precipitation of ANG of rhodium.

RF patent for invention №2194085, IPC: С22В 11/00; publ. 2002.12.10

Known "Method for extracting platinum from chloride solutions" containing platinum and palladium, impurities of other platinum group metals and non-noble elements, including the precipitation of a low-soluble ammonium chloroplatinate salt with stirring using solutions containing ammonium chloride as a precipitant, and the separation of precipitation products by filtration, characterized the fact that the solution to be precipitated platinum is heated to 40-95 ° C, heating is continued during stirring and the heated pulp is subjected to separation by filtration.

RF patent for invention No. 2175677, IPC: С22В 11/00; publ. 2001.11.10

The known method consists in the processing of solutions of chlorocomplexes Rh (III), Ru (IV), Ir (IV) with hydrogen under pressure (Trone V.G. Displacement of platinum metals from solutions of their salts with hydrogen under high pressure // Bulletin of the Academy of Sciences of the USSR, 1937, Department of Mathematical and Natural Sciences, p. 233). But in this method, solutions of chloro complexes Rh (III), Ru (IV) and Ir (IV) were treated in the form of paired systems -Rh (III) -Ru (IV), Rh (III) -Ir (IV).

The closest to the proposed method for separating these metals is "Method for separating metals from an alloy of platinum, palladium, rhodium Pt-Pd-Rh", including dissolving the alloy to obtain a solution of chloro complexes H ₂ PtCl ₆ , H ₂ PdCl ₄ , H ₃ RhCl ₆ , isolation platinum from the resulting solution in the form of ammonium hexachloroplatinate (NH ₄ ) ₂ PtCl ₆ , preparation of an aqueous pulp and treatment of the pulp with carbon monoxide CO at atmospheric pressure and t = 60-70 ° C, characterized in that when the system reaches the value of the redox potential ( ORP) values of 250 mV, the treatment is stopped, the precipitate of palladium and platinum ΣPd, Pt is separated from the solution, and the filtrate continues to be treated with carbon monoxide CO under the same conditions until the redox potential (ORP) is equal to 0mV, after which the precipitate is separated and calcined at 1000 ° C to obtain high-purity platinum Pt, further solutions obtained from the isolation of hexachloroplatinate ammonium (NH ₄ ) ₂ PtCl ₆ , and platinum Pt, are mixed and continue to be treated with carbon monoxide CO at atmospheric pressure and room temperature until the oxidation-reduction potential (ORP) of the system reaches 0mV, while the precipitate of palladium Pd powder is separated from the solution, then the remaining solution is treated with alkali to a pH of ≥8, which results in the release of rhodium Rh in the form of a fine powder, which is separated from the solution after boiling. RF patent for invention No. 2693285, IPC: С22В 11/00; publ. 2019.

The closest to the proposed method for separating these metals is "Method for the selective isolation of rhodium, ruthenium and iridium from a hydrochloric acid solution containing chloro complexes of platinum Pt (IV), palladium Pd (II), gold Au (III), silver Ag (I), rhodium Rh (III), ruthenium Ru (IV), iridium Ir (IV) ”, which includes treating the said solution with carbon monoxide CO at atmospheric pressure, vigorous stirring and heating, followed by filtration. GB patent No. 1507792 A, IPC: C01G5 / 00, publ. 19.04.1978.

The technical result of the invention is to increase the degree of selectivity for extracting rhodium Rh, ruthenium Ru and iridium Ir from a solution of noble metals with a high degree of purity by treatment with hydrogen with various concentrations of H ⁺ ions at a temperature of 95 ° C for six hours.

This result is achieved due to the fact that the “Method for the selective isolation of rhodium Rh, ruthenium Ru and iridium Ir from hydrochloric acid solutions of chloro complexes of platinum Pt (IV), palladium Pd (II), gold Au (III), silver Ag (I), rhodium Rh (III), ruthenium Ru (IV), iridium Ir (IV), includes treating said solution with carbon monoxide CO at atmospheric pressure, vigorous stirring and heating, followed by filtration. In this case, a hydrochloric acid solution is used with an HCl content of 1.5-3, and after filtration, a precipitate is obtained containing Pt, Pd, Au, Ag and a filtrate containing Rh, Ru, Ir in the form of carbonyl chloride complexes Rh (I) -Rh (CO) ₂ Cl ₂ ^- ; Ru (II) -Ru (CO) ₂ Cl ₄ ^-2 and Ir (I) -Ir (CO) ₂ Cl ₂ ^- . Then the resulting filtrate is neutralized to HCl content = 2 mol / l. Then, rhodium, ruthenium and iridium are sequentially isolated from said filtrate, changing the acidity of the solution. In this case, rhodium is isolated from the solution at a temperature of 95 ° C and pH 2 for six hours to obtain a filtrate containing ruthenium and iridium. Then, ruthenium is isolated from the obtained filtrate at a temperature of 95 ° C and pH 5 for six hours. Then the residue of the filtrate containing iridium is treated with chlorine until the oxidation potential is 850 mV, with the formation of a solution of the chloro complex Ir (IV) - [IrCl ₆ ] ^-2 , to which NH ₄ Cl is added and (NN ₄ ) ₂ [IrCl ₆ ] is precipitated. The resulting precipitate is calcined to obtain iridium.

Examples of the proposed method

As a starting solution, we used a solution obtained by hydrochlorination of industrial middlings. This solution contained chloro complexes H ₂ PtCl ₆ , H ₂ PdCl ₄ , H ₃ PhCl ₆ , HAuCl ₄ , HAgCl ₂ , H ₂ RuCl ₆ , H ₂ IrCl ₆ , and Cu. Ni. Fe. The composition of the solution is shown in Table 1.

Example 1. 100 ml of the original solution in a glass reactor was treated with carbon monoxide at atmospheric pressure (bubbling and vigorous stirring at t = 50 ° C for 6 hours). A black metal powder was isolated, which was separated by filtration, washed with 2 molar HCl solution and analyzed for the content of Rh, Ru, Ir, and the filtrate was analyzed for the content of Pt, Pd, Au, Ag.

Example 2. The same operations were carried out as in example 1, but the treatment of the initial CO solution was carried out at t = 65 ° C.

Example 3. Carried out the same operations as in example 1, but the treatment of the original solution with CO was carried out at t = 75 ° C.

Example 4. To 100 ml of the original solution was added hydrochloric acid to a concentration of 2.0 mol / l and the same operations were carried out as in example 1, but at t = 75 ° C.

Example 5. To 100 ml of the original solution was added hydrochloric acid to a concentration of 3.0 mol / l and the same operations were carried out as in example 1, but at t = 85 ° C. The results are shown in Table 2.

From those given in table. 2 of the experimental results, it follows that the precipitation of Σ Pt, Pd, Au, Ag without coprecipitation of Rh, Ru, Ir is achieved when the solutions of chloro complexes of these elements are treated with carbon monoxide with the HCl content in the initial solution at 1.5 mol / l.

Example 6.

500 ml of the initial solution with a concentration of HCl = 2 mol / l in a glass reactor was treated with carbon monoxide at atmospheric pressure and t = 85 ° C for 6 hours. The precipitated powder precipitate Σ Pt, Pd, Au, Ag was separated from the solution, which contained the carbonyl chloride complexes Rh (I), Ru (II), and Ir (I), formed in accordance with reactions (5-7). 200 ml of the resulting filtrate was treated with hydrogen at atmospheric pressure, t = 95 ° C and pH 2 for 6 hours. A black powder precipitate was obtained, which, according to the analysis data, was Rh without Ru and Ir impurities, and its recovery from solution was> 99.9%. Sediment Σ Pt, Pd, Au, Ag concentrate was analyzed for the content of noble metals, copper, nickel, iron. The composition of the sediment is shown in Table 3.

Example 7. As a starting solution, 100 ml of filtrate was used after separation of the Σ Pt, Pd, Au, Ag precipitate obtained in example 6, in which the acidity was brought to a value of 1 mol / l by neutralization. (pH 2). This solution was treated with hydrogen under conditions similar to example 6. A black powder separated out, which was filtered off. According to the analysis, it was a mixture of Rh and Ru, the recovery of which in the sediment was> 99.9% for Rh and 0.1% for Ru.

Example 8. As a starting solution, we used 100 ml of the filtrate from the precipitation of Rh in example 6, neutralized to pH 3 and treated with hydrogen under conditions similar to example 6. A black powder precipitate was obtained. Analysis showed that this is Ru without Ir impurity. Its recovery was 78.32%.

Example 9. As a starting solution, 100 ml of the filtrate obtained in example 6 was used, neutralized to pH 5 and treated with hydrogen under conditions similar to example 6. A black powder was obtained, the analysis of which showed that it was Ru without admixtures of Rh and Ir, and the extraction Ru was> 99.9%.

Example 10

As a starting solution, the filtrate obtained according to example 9, in which only Ir was present, was used. This solution was treated with chlorine to a value of the oxidation potential of 850 mV, and then _{Ir was precipitated by the action of NH 4} Cl in the form of (NH ₄ ) ₂ IrCl ₆ , which was separated and calcined. An Ir powder was obtained, in which, according to the analysis, Rh and Ru were absent.

The results of the experiments described in examples 6-9 are shown in table 4.

From the results of the experiments presented in table. 4, it follows that by treating solutions containing carbonyl chloride complexes Rh (I), Ru (II), and Ir (I) with hydrogen at atmospheric pressure and t = 95 ° C, these metals can be sequentially separated by changing the acidity of the solution.

Therefore, the application of the above method will increase the degree of selectivity for the extraction of rhodium Rh, ruthenium Ru and iridium Ir from a solution of noble metals with a high degree of purity by treatment with hydrogen with different concentrations of H ⁺ ions.

Claims (1)

A method for the selective isolation of rhodium Rh, ruthenium Ru and iridium Ir from a hydrochloric acid solution containing chloro complexes of platinum Pt (IV), palladium Pd (II), gold Au (III), silver Ag (I), rhodium Rh (III), ruthenium Ru ( IV), iridium Ir (IV), including the treatment of said solution with carbon monoxide CO at atmospheric pressure, vigorous stirring and heating, followed by filtration, characterized in that a hydrochloric acid solution is used with an HCl content of 1.5-3 mol / l, and after filtration a precipitate containing Pt, Pd, Au, Ag is obtained, and a filtrate containing Rh, Ru, Ir in the form of carbonyl chloride complexes Rh (I) -Rh (CO) ₂ Cl ₂ ^- , Ru (II) -Ru (CO) ₂ Cl ₄ ^-2 and Ir (I) -Ir (CO) ₂ Cl ₂ ^- , after which the resulting filtrate is neutralized to HCl content = 2 mol / l, then rhodium, ruthenium and iridium are sequentially isolated from the filtrate, changing the acidity of the solution, while rhodium is isolated from the solution at a temperature of 95 ° C and pH 2 for six hours to obtain a filtrate containing ruthenium and iridium, after which ruthenium is isolated from the resulting filtrate at a temperature of 95 ° C and pH 5 for six hours, then the residue of the filtrate containing iridium is treated with chlorine to an oxidation potential of 850 mV to form a solution of the chloro complex Ir (IV) - [IrCl6] ^{- 2} , to which NH ₄ Cl is added and (NH ₄ ) ₂ [IrCl ₆ ] is precipitated, the resulting precipitate is calcined to obtain iridium.