Method for enriching platinum and palladium from material containing high copper and sulfur

Abstract

The invention relates to the technical field of precious metal extraction, in particular to a method for enriching platinum and palladium from a material containing high copper and sulfur. Oxidizing roasting; leaching with hydrochloric acid; copper precipitation treatment and ammonium chloride precipitation. In the oxidizing roasting stage, roasting is conducted in the oxygen atmosphere, the interference of sulfur on follow-up platinum and palladium enrichment is effectively reduced, a pretreated material and lead oxide are mixed according to the specific mass ratio, platinum and palladium elementary substances are converted into composite oxide easily dissolved in hydrochloric acid, and follow-up leaching of platinum and palladium is facilitated; in the hydrochloric acid leaching link, platinum, palladium and copper in the roasted product are fully dissolved, and the metal leaching rate is increased; during copper deposition treatment, iron powder is added according to the accurate molar ratio of the iron powder to copper ions, the copper ions are converted into copper slag precipitates, and efficient separation of copper, platinum and palladium is achieved; in the ammonium chloride precipitation step, ammonium chloride is accurately added according to the total molar weight of platinum and palladium in the filtrate, so that platinum and palladium are fully precipitated, and crude platinum and palladium products are obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of noble metal extraction, in particular to a method for enriching platinum and palladium from a material containing high copper and sulfur. BACKGROUND

[0002] The material containing high copper and sulfur is a common complex ore or industrial waste. Such material not only contains high copper and sulfur, but also often contains noble metal elements such as platinum and palladium. Platinum and palladium have irreplaceable important application value in many fields such as automobile catalytic converter, electronic industry, chemical catalysis and jewelry due to their unique physical and chemical properties, and belong to scarce and precious strategic resources. However, due to the complex composition of the material containing high copper and sulfur, the presence of copper, sulfur and other elements will seriously interfere with the separation and enrichment process of platinum and palladium, making it a challenging technical problem to efficiently and economically recover platinum and palladium from such material. At present, there are mainly the following problems in the extraction of platinum and palladium from the material containing high copper and sulfur: first, it is difficult to effectively remove impurities such as copper and sulfur in the material, resulting in complex subsequent platinum and palladium separation process, low recovery rate, and difficult to guarantee product quality; second, the reagent selected in the extraction process has high cost or harsh operating conditions, and strict requirements for equipment, thereby increasing the production cost and limiting its large-scale industrial application; third, a large amount of waste gas, waste residue and other pollutants are generated in the extraction process, causing great pressure on the environment. SUMMARY

[0003] In view of the problems of difficult extraction and low recovery rate of platinum and palladium in the prior art, the present application provides a method for enriching platinum and palladium from a material containing high copper and sulfur.

[0004] To achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0005] A method for enriching platinum and palladium from a material containing high copper and sulfur, comprising the following steps:

[0006] S1, pretreatment: crushing the material containing high copper and sulfur to a particle size of less than 100 mesh to obtain pretreated material;

[0007] S2, oxidation roasting: mixing the pretreated material with lead oxide at a mass ratio of 1:(0.5-1.5), roasting at 500-700℃ in oxygen atmosphere for 2-4h, cooling to obtain a roasting product;

[0008] S3, hydrochloric acid leaching: adding the roasting product to a hydrochloric acid solution at a liquid-solid ratio of (3-5):1, leaching at 60-80℃ for 1-3h, filtering to obtain a leaching solution containing platinum, palladium and copper;

[0009] S4, copper precipitation: iron powder is added to the leaching solution, the molar ratio of the amount of iron powder added to the copper ions in the leaching solution is (1.2-1.5):1, and the reaction is carried out at 40-60℃ for 1-2h, and then filtration is performed to obtain a filtrate containing platinum and palladium and a copper residue;

[0010] S5, ammonium chloride precipitation: ammonium chloride is added to the filtrate containing platinum and palladium, the molar ratio of the amount of ammonium chloride added to the platinum and palladium in the filtrate is (2-3):1, and the reaction is carried out for 1-2h, and then solid-liquid separation is performed after standing to obtain a crude platinum and palladium product and a filtrate containing ammonium chloride.

[0011] Further, in S2, the oxygen flow rate is 5-10L / min.

[0012] Further, in S3, the concentration of hydrochloric acid is 2-4mol / L.

[0013] Further, in S4, the concentration of copper ions in the platinum and palladium-containing filtrate after copper precipitation is less than 10mg / L.

[0014] Further, in S5, the total content of platinum and palladium in the crude platinum and palladium product is not less than 10%.

[0015] The reaction mechanism involved in the present application is as follows:

[0016] In the oxidation roasting stage, the sulfur element in the pretreated material is oxidized to sulfur dioxide and discharged, and the lead oxide is used as a mineral phase regulator to react with platinum and palladium to form complex oxides PtO·PbO and PdO·PbO which are easily soluble in hydrochloric acid, thereby facilitating subsequent leaching, and the reaction equation is as follows:

[0017]

[0018]

[0019] Copper is oxidized by oxygen to form copper oxide, which facilitates subsequent leaching, and the reaction equation is as follows:

[0020]

[0021] In the hydrochloric acid leaching stage, the complex oxides PtO·PbO and PdO·PbO react with hydrochloric acid to form chloroplatinic acid (H2PtCl4), chloropalladic acid (H2PdCl4) and lead chloride (PbCl2), and platinum and palladium enter the leaching solution in the form of complex ions; copper oxide reacts with hydrochloric acid to form copper chloride, and copper ions enter the leaching solution; and the reaction equation is as follows:

[0022] PtO·PbO+4HCl→H2PtCl4+PbCl2+2H2O

[0023] PdO·PbO+4HCl→H2PdCl4+PbCl2+2H2O

[0024] CuO + 2HCl → CuCl2 + H2O

[0025] In the copper precipitation stage, the reducing property of iron is stronger than that of copper, so copper is displaced, and the concentration of copper ions in the solution is reduced, so that the concentration of copper ions in the filtrate containing platinum and palladium after copper precipitation treatment is less than 10 mg / L, thereby avoiding interference with subsequent platinum and palladium precipitation.

[0026] The reaction equation of the ammonium chloride precipitation stage is as follows:

[0027] H2PtCl4 + 2NH4Cl → (NH4)2PtCl6↓ + 2HCl

[0028] H2PdCl4 + 2NH4Cl → (NH4)2PdCl6↓ + 2HCl

[0029] Compared with the prior art, the method has the following beneficial effects:

[0030] The method for enriching platinum and palladium from a material containing high copper and sulfur provided by the application comprises the following steps: in the oxidation roasting stage, roasting in an oxygen atmosphere can efficiently oxidize sulfur in the material into sulfur dioxide and discharge the sulfur dioxide, thereby effectively reducing the interference of sulfur on subsequent enrichment of platinum and palladium; mixing the pretreated material with lead oxide at a specific mass ratio converts platinum and palladium into a complex oxide that is easily dissolved in hydrochloric acid, thereby facilitating subsequent leaching of platinum and palladium; in the hydrochloric acid leaching link, by controlling the liquid-solid ratio, temperature and reaction time, platinum, palladium and copper in the roasting product are fully dissolved, thereby improving the metal leaching rate; in the copper precipitation treatment, iron powder is added according to an accurate molar ratio of the iron powder to copper ions, so that the copper ions are converted into copper residue and precipitated, thereby realizing efficient separation of copper from platinum and palladium; in the ammonium chloride precipitation step, ammonium chloride is accurately added according to the total molar amount of platinum and palladium in the filtrate, so that platinum and palladium are fully precipitated, thereby obtaining a crude platinum and palladium product. The method is simple to operate and the conditions are controllable, can significantly improve the enrichment efficiency and product quality of platinum and palladium, and has high practical application value. BRIEF DESCRIPTION OF DRAWINGS The embodiments of the application will be further described below with reference to the accompanying drawings, in which: Figure 1 The process flow diagram of the application is shown. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical scheme and advantages of the application clearer, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.

[0032] Embodiment 1

[0033] A method for enriching platinum and palladium from a material containing high copper and sulfur comprises the following steps:

[0034] S1, pretreatment: crushing the material containing high copper and sulfur to a particle size of less than 100 mesh to obtain pretreated material;

[0035] S2, oxidative roasting: mixing the pretreated material with lead oxide at a mass ratio of 1:0.5, roasting at 700°C in an oxygen atmosphere for 2h, the oxygen flow rate is 5L / min, cooling to obtain a roasting product;

[0036] S3, hydrochloric acid leaching: adding the roasting product to a 4mol / L hydrochloric acid solution at a liquid-solid ratio of 3:1, leaching at 80°C for 1h, filtering to obtain a leaching solution containing platinum, palladium and copper;

[0037] S4, copper precipitation treatment: adding iron powder to the leaching solution, the molar ratio of the amount of iron powder added to the copper ions in the leaching solution is 1.2:1, reacting at 60°C for 1h, filtering to obtain a filtrate containing platinum and palladium and a copper residue, the copper ion concentration in the filtrate containing platinum and palladium is 9mg / L;

[0038] S5, ammonium chloride precipitation: adding ammonium chloride to the filtrate containing platinum and palladium, the molar ratio of the amount of ammonium chloride added to the platinum and palladium in the filtrate is 2:1, reacting for 1h, after standing, solid-liquid separation is performed to obtain a crude platinum and palladium product and a filtrate containing ammonium chloride, the total content of platinum and palladium in the crude platinum and palladium product is 10%.

[0039] Example 2

[0040] A method for enriching platinum and palladium from a material containing high copper and sulfur, comprising the following steps:

[0041] S1, pretreatment: crushing the material containing high copper and sulfur to a particle size of less than 100 mesh to obtain pretreated material;

[0042] S2, oxidative roasting: mixing the pretreated material with lead oxide at a mass ratio of 1:1.5, roasting at 500°C in an oxygen atmosphere for 4h, the oxygen flow rate is 10L / min, cooling to obtain a roasting product;

[0043] S3, hydrochloric acid leaching: adding the roasting product to a 2mol / L hydrochloric acid solution at a liquid-solid ratio of 5:1, leaching at 60°C for 3h, filtering to obtain a leaching solution containing platinum, palladium and copper;

[0044] S4, copper precipitation treatment: adding iron powder to the leaching solution, the molar ratio of the amount of iron powder added to the copper ions in the leaching solution is 1.5:1, reacting at 40°C for 2h, filtering to obtain a filtrate containing platinum and palladium and a copper residue, the copper ion concentration in the filtrate containing platinum and palladium is 8mg / L;

[0045] S5, ammonium chloride precipitation: ammonium chloride was added to the filtrate containing platinum and palladium, the molar ratio of the amount of ammonium chloride added to platinum and palladium in the filtrate was 3:1, and the reaction was carried out for 2h. After standing, solid-liquid separation was carried out to obtain a crude platinum and palladium product and a filtrate containing ammonium chloride. The total content of platinum and palladium in the crude platinum and palladium product was 12.6%.

[0046] Example 3

[0047] A method for enriching platinum and palladium from a material containing high copper and sulfur, comprising the following steps:

[0048] S1, pretreatment: crushing the material containing high copper and sulfur to a particle size of less than 100 mesh to obtain a pretreated material;

[0049] S2, oxidative roasting: mixing the pretreated material with lead oxide at a mass ratio of 1:1, roasting at 600°C in an oxygen atmosphere for 3h, and the oxygen flow rate was 7L / min. After cooling, a roasted product was obtained;

[0050] S3, hydrochloric acid leaching: adding the roasted product to a 3mol / L hydrochloric acid solution at a liquid-solid ratio of 4:1, leaching at 70°C for 2h, and filtering to obtain a leaching solution containing platinum, palladium and copper;

[0051] S4, copper precipitation treatment: adding iron powder to the leaching solution, the molar ratio of the amount of iron powder added to copper ions in the leaching solution was 1.4:1, and the reaction was carried out at 50°C for 1.5h. After filtering, a filtrate containing platinum and palladium and a copper residue were obtained, and the concentration of copper ions in the filtrate containing platinum and palladium was 9mg / L;

[0052] S5, ammonium chloride precipitation: ammonium chloride was added to the filtrate containing platinum and palladium, the molar ratio of the amount of ammonium chloride added to platinum and palladium in the filtrate was 2.5:1, and the reaction was carried out for 1.5h. After standing, solid-liquid separation was carried out to obtain a crude platinum and palladium product and a filtrate containing ammonium chloride. The total content of platinum and palladium in the crude platinum and palladium product was 11.8%.

[0053] The present invention provides a method for enriching platinum and palladium from a material containing high copper and sulfur. In the oxidation roasting stage, the material is roasted in an oxygen atmosphere, and the sulfur in the material can be efficiently oxidized to sulfur dioxide for discharge, effectively reducing the interference of sulfur on the subsequent enrichment of platinum and palladium. The pretreated material is mixed with lead oxide in a specific mass ratio to convert platinum and palladium elements into composite oxides that are easily soluble in hydrochloric acid, which is convenient for the subsequent leaching of platinum and palladium. In the hydrochloric acid leaching step, the platinum, palladium and copper in the roasted product are fully dissolved by controlling the liquid-solid ratio, temperature and reaction time, thereby improving the metal leaching rate. During the copper precipitation process, iron powder is added according to an accurate molar ratio of iron powder to copper ions, and copper ions are converted into copper slag precipitation, thereby achieving efficient separation of copper from platinum and palladium. In the ammonium chloride precipitation step, ammonium chloride is accurately added according to the total molar amount of platinum and palladium in the filtrate, so that platinum and palladium are fully precipitated to obtain crude platinum and palladium products. The method is simple to operate, has controllable conditions, can significantly improve the enrichment efficiency and product quality of platinum and palladium, and has high practical application value.

[0054] Some exemplary embodiments of the present invention are described above. It will be understood that the above embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention. The features in these embodiments can be recombined in an appropriate manner, and the solutions obtained thereby are still within the scope of protection claimed by the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without making creative work, that is, all modifications, equivalent substitutions and improvements made within the spirit and principles of this application, fall within the scope of protection claimed by the present invention.

Claims

1. A method for enriching platinum and palladium from a material containing high copper and sulfur, characterized in that: The following steps are involved: S1. Pretreatment: crushing the material containing high copper and sulfur to a particle size of less than 100 mesh to obtain pretreated material; S2, oxidizing roasting: mixing the pretreated material with lead oxide in a mass ratio of 1:(0.5-1.5), roasting at 500-700°C in an oxygen atmosphere for 2-4 hours, and cooling to obtain a roasted product; S3. Hydrochloric acid leaching: add the roasted product to a hydrochloric acid solution at a liquid-to-solid ratio of (3-5):1, soak at 60-80°C for 1-3 hours, filter, and obtain a leachate containing platinum, palladium, and copper; S4, copper precipitation treatment: adding iron powder to the leachate, with a molar ratio of iron powder to copper ions in the leachate being (1.2-1.5):1, reacting at 40-60°C for 1-2h, filtering to obtain a filtrate containing platinum and palladium and copper slag; S5. Ammonium chloride precipitation: add ammonium chloride to the filtrate containing platinum and palladium, with the molar ratio of ammonium chloride added to platinum and palladium in the filtrate being (2-3):1, react for 1-2 hours, stand for solid-liquid separation, and obtain crude platinum and palladium products and a filtrate containing ammonium chloride.

2. The method for enriching platinum and palladium from a material containing high copper and sulfur according to claim 1, characterized in that: In S2, the oxygen flow rate is 5-10 L / min.

3. The method for enriching platinum and palladium from a material containing high copper and sulfur according to claim 1, characterized in that: In S3, the concentration of hydrochloric acid is 2-4 mol / L.

4. The method for enriching platinum and palladium from a material containing high copper and sulfur according to claim 1, characterized in that: In S4, the copper ion concentration in the platinum- and palladium-containing filtrate after copper precipitation treatment is less than 10 mg / L.

5. The method for enriching platinum and palladium from a material containing high copper and sulfur according to claim 1, characterized in that: In S5, the total content of platinum and palladium in the crude platinum and palladium products is not less than 10%.

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