A process for comprehensive recovery of nickel, ruthenium and platinum valuable metals from precious metal-containing materials

Abstract

The present invention is a process for comprehensively recovering nickel, ruthenium and platinum valuable metals from precious metal materials. The precious metal-containing materials are used as raw materials to recover nickel, ruthenium and platinum valuable metals. The process only uses sulfuric acid, nitric acid and hydrogen peroxide, and no other inorganic salts are added. This ensures that the entire system does not generate industrial wastewater and the production cost is relatively low.

Description

Technical Field

[0001] The present invention is a process for comprehensively recovering nickel, ruthenium and platinum valuable metals from precious metal materials. The process uses precious metal-containing materials as raw materials to recover nickel, ruthenium and platinum valuable metals from the materials, and belongs to the technical field of comprehensive recovery of valuable metals. Background Art

[0002] In the process of dismantling waste resources such as waste circuit boards and waste electronic components, a large amount of metal waste will be generated. In addition to several non-ferrous metals such as copper, nickel, and iron, some metal wastes also contain precious metals such as gold, platinum, ruthenium, and palladium. At present, the main method is to leach the base metals in the leaching process to enrich the precious metals, and to separate and recover the precious metals using conventional precious metal processes. However, in the current physical production process, while leaching non-ferrous metals such as copper, nickel, and iron, about 5% of the precious metals will also enter the leachate at the same time. Although the precious metals in the leachate can be recovered by precipitation, ion adsorption, and other methods, this not only increases the production cost of the entire process, but also disperses the precious metals, reducing the direct recovery rate of the precious metals. At the same time, there is more than one base metal in the leachate, and the base metals need to be separated one by one, which increases the production cost.

[0003] Chinese patent CN201210095580.8 discloses a method for selectively separating valuable metals from complex lead-containing precious metal materials, including low-temperature alkaline smelting and water leaching steps, and finally obtaining leaching residue and leaching filtrate; wherein more than 85% of gold, more than 99% of silver, more than 89% of tellurium, and 100% of lead and bismuth are enriched in the leaching residue; after evaporation and concentration of the leaching filtrate, mixed crystals such as Na2SbS3 and Na3SbS3 are obtained; the lead, bismuth, gold, silver, and tellurium enriched in the leaching residue in the above process can be further separated and recovered by existing pyrometallurgy to obtain lead, bismuth and precious metals, and the mixed crystals after evaporation and concentration of the leaching filtrate can be used as raw materials for extracting metals or step-by-step production of chemical products such as antimony white and sodium stannate. This method uses a pyrometallurgy + hydrometallurgy pretreatment process, which not only has high production costs, but also only 85% of the gold remains in the slag, which makes the precious metals dispersed in water and solution.

[0004] Chinese patent CN202210214036.4 discloses a method for removing impurities from a high-iron-containing precious metal alloy, by adding hydrochloric acid or sulfuric acid to the high-iron-containing precious metal alloy, leaching the iron and other base metals therein at room temperature and pressure, and then adding hydrogen peroxide to remove the residual Fe in the slag. 2+ Oxidized to Fe 3+ , using Fe 3+The strong oxidizing property of the slag is used in combination with hydrogen peroxide to continue dissolving the remaining base metals and precious metals in the slag. Finally, alkali is added to produce iron hydroxide colloid in the solution to absorb silicon and trace base metal elements, thereby achieving the purpose of deep impurity removal. This method leaches base metals and precious metals together, making the content of base metals in the leachate far greater than that of precious metals, which is not conducive to the recovery of precious metals. At the same time, iron hydroxide colloid will also absorb precious metals, resulting in precious metal recovery losses.

[0005] Chinese patent CN201611245668.8 discloses a method for extracting gold, platinum and palladium from copper anode mud of electronic waste, which comprises: (1) mixing the copper anode mud of electronic waste with an oxidant and an additive and subjecting it to a chlorination oxidation leaching treatment to obtain a leaching slurry; (2) filtering the leaching slurry to obtain a filtrate and a filter residue containing gold, platinum and palladium; (3) mixing the filtrate with a gold extractant and subjecting it to an extraction treatment to obtain a gold-loaded organic phase and a raffinate containing platinum and palladium; (4) subjecting the gold-loaded organic phase to a back extraction treatment with oxalic acid to obtain an organic solution and gold powder; (5) subjecting the raffinate containing platinum and palladium to an adsorption treatment with an anion exchange resin; and (6) subjecting the anion exchange resin adsorbed with platinum and palladium to a desorption treatment with hydrochloric acid to obtain platinum and palladium. This method uses agents such as sulfuric acid and sodium chlorate, which makes the wastewater rich in inorganic salt ions such as sulfate and chloride ions, and it is impossible to make the wastewater a resource. Summary of the invention

[0006] In view of some problems existing in the prior art, the present invention proposes a process for comprehensively recovering valuable metals such as nickel, ruthenium and platinum from precious metal-containing materials; the process only uses sulfuric acid, nitric acid and hydrogen peroxide, without adding other inorganic salts, which makes the entire system free of industrial wastewater and has relatively low production costs.

[0007] The technical solution of the present invention is as follows: a process for comprehensively recovering nickel, ruthenium and platinum valuable metals from precious metal-containing materials; the following steps are adopted:

[0008] (1) Primary leaching of precious metal-containing materials: the leaching temperature is 80-95°C, the leaching time is 2-3 hours, the liquid-to-solid volume mass ratio is 4-6:1 mL / g, and the amount of sulfuric acid added is 200%-250% of the mass of the precious metal-containing material. After the reaction is completed, a primary leaching liquid and a primary leaching residue are obtained;

[0009] (2) Primary replacement: Add precious metal-containing materials to the primary leaching solution, control the pH to 2-3 after the reaction, the replacement temperature to 80-95°C, the replacement time to 2-3h, and obtain the primary replacement residue and primary replacement liquid after filtering after the reaction.

[0010] (3) Ferrous sulfate crystallization: The ferrous sulfate in the primary replacement liquid is crystallized by conventional evaporation crystallization method to obtain pure ferrous sulfate crystals and crystallization mother liquor, and the crystallization mother liquor is returned to the primary leaching;

[0011] (4) Secondary leaching: Add nitric acid to the primary leaching residue. The leaching temperature is room temperature. The leaching time is 2-3 hours. The liquid-to-solid volume mass ratio is 6-8:1 mL / g. The amount of nitric acid added is 300%-320% of the mass of the primary leaching residue (or the returned secondary replacement residue). After the reaction is completed, secondary leaching liquid and secondary leaching residue are obtained. The secondary leaching residue is the precious metal enriched residue and can be directly sent to the precious metal recovery process.

[0012] (5) Secondary replacement: add the primary replacement residue to the secondary leaching solution, control the pH value to 2.5-3 after the reaction is completed, the replacement temperature is room temperature, the replacement time is 2-3 hours, after the reaction is completed, filter to obtain secondary replacement residue and secondary replacement liquid, and return the secondary replacement residue to the secondary leaching;

[0013] (6) Oxidation for iron removal: Add hydrogen peroxide to the secondary replacement solution in an amount of 1.0 to 1.2 times the mass of iron in the solution. After reacting for 1 to 2.5 hours, filter to obtain nickel nitrate or copper nitrate purified solution and iron slag.

[0014] (7) Crystallization of nickel nitrate or copper nitrate: The nickel nitrate or copper nitrate in the nickel nitrate or copper nitrate purification solution is crystallized by conventional evaporation crystallization method to obtain pure nickel nitrate or copper nitrate crystals and crystallization mother liquor, and the crystallization mother liquor is returned to secondary leaching.

[0015] The chemical reaction equation of the above process is as follows:

[0016] Fe+H2SO4 = FeSO4+H2

[0017] Ni+H2SO4 = NiSO4+H2

[0018] 3Cu+8HNO3= 3Cu(NO3)2+4H2O +2NO

[0019] 3Ni+8HNO3= 3Ni(NO3)2+4H2O +2NO

[0020] 2Fe+8HNO3= 2Fe (NO3)3+4H2O +2NO

[0021] Fe+ NiSO4 = FeSO4 +Ni

[0022] Fe+Cu(NO3)2=Cu+Fe(NO3)2

[0023] Fe+Ni(NO3)2=Ni+Fe(NO3)2

[0024] Fe+ 2Fe (NO3)3=3 Fe(NO3)2.

[0025] The key technologies of the present invention are:

[0026] (1) During the entire precious metal enrichment process, the loss rate of precious metals such as gold, palladium, ruthenium, and platinum is less than 0.1%, and the precious metals are enriched by more than 50 times. The enriched slag can be directly used for precious metal purification;

[0027] (2) Sulfuric acid and nitric acid are used for staged leaching. The precious metal material itself contains iron, copper, nickel and other metals. The precious metal material is directly used to replace a small amount of precious metals in the leachate. At the same time, the copper and nickel in the primary leachate are replaced by the iron in the precious metal material, and the pH of the two leachates is adjusted to the required value for the subsequent process. In this way, the precious metals in the primary leachate and the secondary leachate can be recovered without increasing the cost. At the same time, the copper and nickel in the primary leachate can be directly replaced, and the primary leachate can be directly converted into a pure ferrous sulfate solution, achieving multiple goals at one stroke.

[0028] (3) The sulfuric acid system and nitric acid system are used to recover ferrous sulfate and nickel nitrate (or copper nitrate) respectively. The entire industry only uses sulfuric acid, nitric acid and hydrogen peroxide. The solution is evaporated and crystallized to obtain the crystal product and pure sulfuric acid or nitric acid mother liquor. The mother liquor can be returned to the leaching process. The entire process does not discharge industrial wastewater, ensuring that there is no wastewater discharge during production.

[0029] (4) Since the entire process system only uses cheap sulfuric acid, nitric acid, and hydrogen peroxide, the entire system has low production costs and good production benefits.

[0030] Compared with the prior art, the present invention first uses sulfuric acid solution to leach the precious metal material once to obtain a primary leachate of the primary leaching slag; uses a certain amount of precious metal material and the primary leachate to carry out a replacement reaction to obtain a primary replacement liquid and a primary replacement slag, so that a small amount of precious metals and relatively inactive base metals in the primary leachate are replaced into the replacement slag, and the leachate is a relatively pure active metal solution, and a relatively pure metal sulfate crystal can be obtained after evaporation and crystallization; uses a dilute nitric acid solution to carry out a secondary leaching of the primary leaching slag to obtain a secondary metal slag (i.e., precious metal enriched slag) and a secondary leachate, uses the primary replacement slag and the secondary leachate to carry out a replacement reaction, so that the precious metal in the secondary leachate enters the secondary replacement slag, and the secondary replacement slag returns to the secondary leaching, and the secondary metal liquid is purified, evaporated and crystallized to obtain pure metal nitrate crystals. The whole process only uses sulfuric acid, nitric acid, and hydrogen peroxide, and no other inorganic salts are added, so that the whole system does not generate industrial wastewater, the production cost is relatively low, and it has good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a process flow chart of the present invention.

[0032] In the figure, the precious metal-containing material is first leached once with sulfuric acid solution to obtain a primary leachate and a primary leach residue; the precious metal-containing material is added to the primary leachate, and after the reaction is completed and filtered, a primary replacement residue and a primary replacement liquid are obtained; the ferrous sulfate in the primary replacement liquid is crystallized by a conventional evaporation crystallization method to obtain pure ferrous sulfate crystals and a crystallization mother liquor, and the crystallization mother liquor is returned to the primary leaching; the primary leaching residue (or the returned secondary replacement residue) is subjected to secondary leaching with a dilute nitric acid solution to obtain a secondary metal slag (i.e., precious metal enriched slag) and a secondary leachate; the secondary leaching residue is directly sent to the precious metal recovery process; the primary replacement residue and the secondary leachate are subjected to a replacement reaction, and after the reaction is completed and filtered, a secondary replacement residue and a secondary replacement liquid are obtained, and the secondary replacement residue is returned to the secondary leaching; hydrogen peroxide is added to the secondary replacement liquid, and filtered after the reaction; nickel nitrate or copper nitrate purified liquid and iron slag are obtained; the nickel nitrate or copper nitrate in the nickel nitrate or copper nitrate purified liquid is crystallized by a conventional evaporation crystallization method to obtain pure nickel nitrate or copper nitrate crystals and a crystallization mother liquor, and the crystallization mother liquor is returned to the secondary leaching. DETAILED DESCRIPTION

[0033] Example 1

[0034] (1) Take 100g of precious metal-containing material, of which iron is 61.16%, copper is 32.26%, gold is 126.12g / t, platinum is 116.29g / t, and palladium is 100.32g / t;

[0035] (2) Primary leaching of precious metal-containing materials: The leaching temperature is 85°C, the leaching time is 2h, 120mL of sulfuric acid and 420mL of water are added, and after the reaction, 512mL of primary leaching liquid and 62.53g of primary leaching residue are obtained. The primary leaching liquid contains 60.92g / L of iron, 1.46g / L of copper, 2.22mg / L of gold, 0.20mg / L of platinum, and 0.24mg / L of palladium; the primary leaching residue contains 47.92% of iron and 50.39% of copper;

[0036] (3) Primary replacement: fresh precious metal-containing materials were added to the primary leaching solution, and the pH was controlled to be 2.5 after the reaction was completed. The replacement temperature was 85°C and the replacement time was 2.5 h. After the reaction was completed and filtered, 93.58 g of primary replacement slag and 510 mL of primary replacement liquid were obtained. The primary replacement liquid contained 149.80 g / L of iron, 1.12 mg / L of copper, and no gold, platinum, or palladium was detected.

[0037] (4) Ferrous sulfate crystallization: The ferrous sulfate in the primary replacement solution was crystallized by conventional evaporation crystallization method to obtain 377.60 g of pure ferrous sulfate heptahydrate, which contained 20.03% iron. The crystallization mother liquor was returned to the primary leaching;

[0038] (5) Secondary leaching: 62.53 g of the primary leaching residue was taken, the leaching temperature was room temperature, the leaching time was 2 h, the amount of water added was 300 mL, the amount of nitric acid added was 128 mL, and after the reaction was completed, 410 mL of secondary leaching solution and 0.2601 g of secondary leaching residue were obtained. The secondary leaching residue was the precious metal enriched residue, which contained 17.64% iron, 20.22% copper, 47.2076% gold, 4.3903% platinum, and 3.5212% palladium; the secondary leaching solution contained 72.63 g / L iron, 76.35 g / L copper, 5.45 mg / L gold, 0.27 mg / L platinum, and 1.84 mg / L palladium;

[0039] (6) Secondary replacement: add primary replacement slag to secondary leaching solution, control the pH value at 2.5 after the reaction, keep the replacement temperature at room temperature, and the replacement time at 3 h. After the reaction is completed and filtered, 10.32 g of secondary replacement slag and 403 mL of secondary replacement liquid are obtained, which contain 88.56 g / L of iron and 85.32 g / L of copper, and no gold, platinum, or palladium is detected.

[0040] (7) Oxidation for iron removal: Add 39.25 g of hydrogen peroxide to the secondary replacement solution, react for 2 hours, and then filter. The copper nitrate purified solution and iron slag are obtained;

[0041] (8) Crystallization of copper nitrate: The copper nitrate in the copper nitrate purification solution was crystallized by conventional evaporation crystallization method to obtain 96.54 g of pure copper nitrate trihydrate, which contained 35.26% copper. The crystallization mother liquor was returned to the secondary leaching.

[0042] Example 2

[0043] (1) Take 100g of precious metal-containing material, of which iron is 56.25%, nickel is 38.11%, gold is 111.56g / t, platinum is 456.13g / t, and ruthenium is 2120.36g / t;

[0044] (2) Primary leaching of precious metal-containing materials: The leaching temperature is 90°C, the leaching time is 3h, 125mL of sulfuric acid and 420mL of water are added, and after the reaction, 530mL of primary leaching liquid and 43.29g of primary leaching residue are obtained. The primary leaching liquid contains 77.47g / L of iron, 22.13g / L of nickel, 0.19mg / L of gold, 0.75mg / L of platinum, and 0.4.97mg / L of ruthenium; the primary leaching residue contains 35.08% of iron and 60.93% of nickel;

[0045] (3) Primary replacement: fresh precious metal-containing materials were added to the primary leaching solution, and the pH was controlled to be 2.8 after the reaction was completed. The replacement temperature was 90°C and the replacement time was 3 h. After the reaction was completed and filtered, 40.28 g of primary replacement slag and 520 mL of primary replacement liquid were obtained. The primary replacement liquid contained 145.21 g / L of iron, 0.98 mg / L of nickel, and no gold, platinum, or ruthenium was detected.

[0046] (4) Ferrous sulfate crystallization: The ferrous sulfate in the primary replacement solution was crystallized by conventional evaporation crystallization method to obtain 373.30 g of pure ferrous sulfate heptahydrate, which contained 20.01% iron. The crystallization mother liquor was returned to the primary leaching;

[0047] (5) Secondary leaching: 43.29 g of the primary leaching residue was taken, the leaching temperature was room temperature, the leaching time was 3 h, the amount of water added was 220 mL, the amount of nitric acid added was 90 mL, and after the reaction was completed, 300 mL of secondary leaching solution and 0.32 g of secondary leaching residue were obtained. The secondary leaching residue was the precious metal enriched residue, which contained 8.78% iron, 11.90% nickel, 3.3652% gold, 13.9846% platinum, and 59.7411% ruthenium; the secondary leaching solution contained 50.53 g / L iron, 87.80 g / L nickel, 0.95 mg / L gold, 1.53 mg / L platinum, and 61.06 mg / L ruthenium;

[0048] (6) Secondary replacement: add primary replacement slag to secondary leaching solution, control the pH value at 2.6 after the reaction, keep the replacement temperature at room temperature, and take 3 hours for replacement. After the reaction is completed, filter to obtain 12.13 g secondary replacement slag and 292 mL secondary replacement liquid, which contains 56.13 g / L iron, 98.11 g / L nickel, and no gold, platinum, or ruthenium is detected.

[0049] (7) Oxidation for iron removal: Add 18 g of hydrogen peroxide to the secondary replacement solution, react for 2 h, and filter. This will yield nickel nitrate purification solution and iron slag.

[0050] (8) Nickel nitrate crystallization: The nickel nitrate in the nickel nitrate purification solution was crystallized by conventional evaporation crystallization method to obtain 111.01 g of pure nickel nitrate hexahydrate, which contained 25.53% nickel. The crystallization mother liquor was returned to the secondary leaching.

Claims

1. A process for comprehensive recovery of nickel, ruthenium and platinum valuable metals from precious metal-containing materials; characterized in that Use the following steps: (1) Primary leaching of precious metal-containing materials with sulfuric acid: the leaching temperature is 80-95°C, the leaching time is 2-3 hours, the liquid-to-solid volume mass ratio is 4-6:1 mL / g, and the amount of sulfuric acid added is 200%-250% of the mass of the precious metal-containing material. After the reaction is completed, a primary leaching liquid and a primary leaching residue are obtained; (2) Primary replacement: Add precious metal-containing materials to the primary leaching solution, control the pH to 2-3 after the reaction, the replacement temperature to 80-95°C, the replacement time to 2-3h, and obtain the primary replacement residue and primary replacement liquid after filtering after the reaction. (3) Ferrous sulfate crystallization: The ferrous sulfate in the primary replacement liquid is crystallized by conventional evaporation crystallization method to obtain pure ferrous sulfate crystals and crystallization mother liquor, and the crystallization mother liquor is returned to the primary leaching; (4) Secondary leaching: Add nitric acid to the primary leaching residue. The leaching temperature is room temperature. The leaching time is 2-3 hours. The liquid-to-solid volume mass ratio is 6-8:1 mL / g. The amount of nitric acid added is 300%-320% of the mass of the primary leaching residue or the returned secondary replacement residue. After the reaction is completed, secondary leaching liquid and secondary leaching residue are obtained. The secondary leaching residue is the precious metal enriched residue and can be directly sent to the precious metal recovery process. (5) Secondary replacement: add the primary replacement residue to the secondary leaching solution, control the pH value to 2.5-3 after the reaction is completed, the replacement temperature is room temperature, the replacement time is 2-3 hours, after the reaction is completed, filter to obtain secondary replacement residue and secondary replacement liquid, and return the secondary replacement residue to the secondary leaching; (6) Oxidation for iron removal: Add hydrogen peroxide to the secondary replacement solution in an amount of 1.0 to 1.2 times the mass of iron in the solution. After reacting for 1 to 2.5 hours, filter to obtain nickel nitrate or copper nitrate purified solution and iron slag. (7) Crystallization of nickel nitrate or copper nitrate: The nickel nitrate or copper nitrate in the nickel nitrate or copper nitrate purification solution is crystallized by conventional evaporation crystallization method to obtain pure nickel nitrate or copper nitrate crystals and crystallization mother liquor, and the crystallization mother liquor is returned to secondary leaching.

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