A method for efficiently purifying platinum from ferroalloy precious metal-enriched slag solution in a short process

Abstract

The present invention relates to a method for efficiently purifying platinum from a ferroalloy noble metal-enriched slag solution in a short process, and belongs to the technical field of noble metal refining and purification. After the ferroalloy noble metal-enriched slag solution is diluted, an ammonium salt and a reducing agent are added to perform reduction and impurity removal, thereby obtaining a crude ammonium chloroplatinite solution and an insoluble slag; sulfite and ammonium salt are added to the crude ammonium chloroplatinite solution to precipitate platinum in the form of hydroxytrisulfite and ammonium platinate; the hydroxytrisulfite and ammonium platinate slag is dissolved by acid solution, and then precipitated and impurities are removed by diacetyl oxime to obtain a pure ammonium chloroplatinite solution; an oxidant and an ammonium salt are added to the pure ammonium chloroplatinite solution under acidic conditions to perform an oxidation reaction to obtain ammonium chloroplatinate; the ammonium chloroplatinate is slurried with pure water, reduced by a reducing agent, and roasted to obtain refined platinum. The present invention utilizes the difference in solubility properties of platinum ammonium sulfite salts of platinum and rhodium in acid, and controls suitable conditions so that platinum and rhodium can be effectively separated under a reduction system; the present invention can produce refined platinum with a purity of more than 99.99%, and a direct yield of platinum is greater than 98%.

Description

Technical Field

[0001] The invention relates to a method for efficiently purifying platinum in a short process from a ferroalloy noble metal-enriched slag solution, belonging to the technical field of noble metal refining and purification. Background Art

[0002] At present, the method of refining and purifying platinum from the solution of platinum-enriched slag of precious metal iron alloy mainly adopts the addition of ammonium chloride to generate ammonium chloroplatinate, calcining crude ammonium chloroplatinate to generate crude platinum, and then dissolving it twice with aqua regia, and then adding diacetyl oxime to remove palladium, adding alkaline water to remove rhodium, precipitating platinum with ammonium chloride, calcining to generate platinum (or reducing platinum with hydrazine hydrate) and other steps to purify platinum. Another improved process used in production is to use reduction dissolution to make liquid for crude ammonium chloroplatinate, replacing the traditional "calcination of ammonium chloroplatinate-dissolution in aqua regia-dripping out nitrate" process, that is, using a reducing agent to reduce (PtCl6) in ammonium chloroplatinate. 2- Reduction to (PtCl4) 2- , so that the solid ammonium chloroplatinate dissolves into the solution to complete the liquid production, and then a new ammonium chloroplatinate precipitate is generated by adding an oxidant to the ammonium chloroplatinite solution and supplementing ammonium chloride. Sometimes, depending on the amount of impurities and the complexity of the raw materials, it is necessary to repeat the refining operation 2 to 3 times to produce qualified refined platinum products.

[0003] Due to the traditional process of secondary aqua regia dissolution of crude platinum, removal of nitrate and hydrolysis precipitation to remove rhodium, the operation of crude ammonium chloroplatinate with high impurities sometimes needs to be repeated more than three times. Not only is the production cycle long, but the environmental pollution is serious and the processing cost is relatively high.

[0004] For the existing reduction dissolution improvement process, although it can reduce environmental pollution, because the system is a reduction system, rhodium exists in a low-price form, and the effect of hydrolysis to remove rhodium is not as good as the oxidation system of high valence state, and the process of oxidation precipitation of platinum to generate ammonium chloroplatinate is introduced in the later stage, and the purity requirement of ammonium chloroplatinite solution will be higher. If the control potential is improper during oxidation precipitation, impurities are easily introduced. Therefore, in order to obtain a higher purity ammonium chloroplatinite solution, impurity removal processes such as ion exchange and extraction are often introduced, which invisibly disperses the existence of precious metals, greatly reduces the direct yield of platinum, and correspondingly prolongs the recovery process. Especially for the above-mentioned complex composition and relatively high impurity content of materials, it is often necessary to repeat the process of dissolving and ammonium chloride precipitation of platinum for 2 to 3 times. Therefore, compared with traditional processes, the existing improved process also has the problems of long process, long cycle, low recovery rate and high cost. Summary of the invention

[0005] In view of the problems of long process, difficult impurity separation and high cost in the current process of refining platinum from ferroalloy precious metal-enriched slag solution, the present invention proposes a method for efficiently purifying platinum from ferroalloy precious metal-enriched slag solution in a short process. The ferroalloy precious metal-enriched slag solution is a solution obtained by removing a large amount of iron from the ferroalloy containing precious metals through acid dissolution, and then dissolving the acid-insoluble slag after iron removal with aqua regia or acid + oxidant (such as chlorine, hydrogen peroxide or sodium chlorate, etc.). The solution mainly contains platinum ions and also contains a large amount of metal ions including rhodium, palladium, iridium, ruthenium, gold, silver, tin, iron, sodium, potassium, silicon, tungsten, copper, nickel, etc.; the present invention dilutes the ferroalloy precious metal-enriched slag solution, adds ammonium salt and reduces The raw agent is reduced and impurities are removed to obtain a crude ammonium chloroplatinite solution and an insoluble slag (mainly containing impurities such as rhodium, palladium, gold, silver, iron, silicon, tungsten, tin, phosphorus, etc.); sulfite and ammonium salt are added to the crude ammonium chloroplatinite solution to precipitate platinum to obtain hydroxytrisulfite with ammonium platinate slag, and a large amount of base metal impurities and part of ruthenium, rhodium, palladium, etc. remain in the solution; the hydroxytrisulfite with ammonium platinate slag is dissolved in an acid solution, and then precipitated and impurities are removed by diacetyl oxime to obtain a pure ammonium chloroplatinite solution and an insoluble slag mainly containing impurities such as rhodium, palladium, tin, iridium, etc.; an oxidant and ammonium chloride are added to the pure ammonium chloroplatinite solution under acidic conditions for oxidation reaction to obtain ammonium chloroplatinate; the ammonium chloroplatinate is slurried with pure water, reduced with hydrazine hydrate, and roasted to obtain refined platinum. The present invention utilizes the difference in solubility properties of platinum and rhodium ammonium sulfite salt precipitation in acid, and controls suitable conditions so that platinum and rhodium can be effectively separated in a reduction system; the present invention can obtain refined platinum with a purity greater than 99.99%, and the direct recovery rate of platinum is greater than 98%.

[0006] A method for efficiently purifying platinum from ferroalloy precious metal-enriched slag solution in a short process, the specific steps are as follows:

[0007] (1) Add water in an equal volume ratio to dilute the ferroalloy precious metal enriched slag solution, add a reducing agent, react at a temperature of 80-100°C for 60-120 minutes, and separate the solid and liquid to obtain a crude ammonium chloroplatinite solution and an insoluble slag;

[0008] (2) Under stirring conditions at a temperature of 80 to 100° C., the pH value of the crude ammonium chloroplatinite solution is adjusted to 4.5 to 8, and then the sulfite platinum complexing agent and the ammonium salt are simultaneously added to the crude ammonium chloroplatinite solution to react for 60 to 90 minutes, and then cooled and solid-liquid separated to obtain hydroxytrisulfite and ammonium platinate slag;

[0009] (3) At a temperature of 80-100°C and under stirring conditions, add the acid solution to the hydroxytrisulfurous acid and ammonium platinate residue, dissolve and react for 60-120 minutes, add diacetyl oxime and continue to react for 10-20 minutes, cool to room temperature and continue to precipitate for 4-8 hours, and separate the solid and liquid to obtain a pure ammonium chloroplatinite solution;

[0010] (4) Add the ammonium salt and oxidant to the pure ammonium chloroplatinate solution at a temperature of 80-100°C and stirring, and adjust the H + The concentration is 3-6 mol / L, the oxidation reaction is carried out until no precipitation is formed, cooling and crystallization are carried out, solid-liquid separation is carried out, and the solid is washed with acidic ammonium chloride solution A and ammonium chloride solution B in sequence to obtain ammonium chloroplatinate solid;

[0011] (5) Pure water is added to the ammonium chloroplatinate solid to make it slurry, and a reducing agent is slowly added at a temperature of 80-100°C with stirring. A sodium hydroxide solution is used to control the pH value of the slurry to 6-7, and the solution is reacted until it becomes clear. The solution is cooled to room temperature, and the solid-liquid separation is performed to obtain platinum powder. The platinum powder is added to dilute hydrochloric acid and boiled for 10-20 minutes. The solution is cooled to room temperature, and the solid-liquid separation is performed. The solid is washed with pure water until it is neutral, and then calcined at a temperature of 600-700°C for 120-180 minutes to obtain refined platinum. The purity of the refined platinum is >99.99%, and the direct yield is >98%.

[0012] The ferroalloy precious metal enriched slag solution in step (1) contains 50-120 g / L of platinum ions and also contains two or more metal impurity ions selected from rhodium, palladium, iridium, ruthenium, silver, gold, tin, iron, sodium, potassium, silicon, tungsten and copper.

[0013] The reducing agent in step (1) is one or more of oxalic acid, oxalate, hydrazine hydrate, hydrazine hydrochloride, and sulfite. Preferably, the reducing agent is sodium sulfite. The amount of the reducing agent added is 1.1 to 1.3 times the theoretical molar amount of platinum.

[0014] In the step (2), the sulfite platinum complexing agent is one or more of sodium sulfite, sodium bisulfite, ammonium bisulfite, and ammonium sulfite, preferably the sulfite platinum complexing agent is sodium sulfite or sodium bisulfite; the ammonium salt is one or more of ammonium chloride, ammonium sulfate, and ammonium bicarbonate, preferably the ammonium salt is ammonium chloride; the amount of the sulfite platinum complexing agent added is 1.1 to 1.5 times the theoretical molar amount of platinum, and the amount of the ammonium salt added is 0.1 to 0.3 times the theoretical molar amount of platinum.

[0015] The acid solution in step (3) is dilute hydrochloric acid or dilute sulfuric acid, the concentration of dilute hydrochloric acid is 3-6 mol / L, and the concentration of dilute sulfuric acid is 3-6 mol / L; preferably, the acid solution is hydrochloric acid; the mass ratio of the acid solution to the hydroxytrisulfite-platinum ammonium slag is 3-5:1, and the amount of dimethylglyoxime added is 5-10 times the theoretical molar amount of palladium.

[0016] In the step (4), the ammonium salt is ammonium chloride, the amount of ammonium chloride added is 1.2 to 1.5 times the theoretical molar amount of platinum, and the amount of oxidant added is 1.2 to 1.3 times the theoretical molar amount of platinum; the oxidant is sodium chlorate, hydrogen peroxide, sodium hypochlorite, perchloric acid or chlorine gas.

[0017] The temperature of cooling crystallization in step (4) is 25-50° C., the concentration of the acidic ammonium chloride solution A is 2-3 mol / L, the pH is 0.4-0.6, and the mass concentration of the ammonium chloride solution B is 10-20%.

[0018] The amount of pure water added in step (5) is 3 to 10 times the mass of ammonium chloroplatinate.

[0019] The reducing agent in step (5) is hydrazine hydrate or hydrazine hydrochloride, and the amount of the reducing agent added is 1.1 to 1.3 times the theoretical molar amount of platinum.

[0020] The concentration of the dilute hydrochloric acid in step (5) is 3-5 mol / L, and the mass ratio of platinum powder to dilute hydrochloric acid is 1:5-10.

[0021] The beneficial effects of the present invention are:

[0022] (1) The present invention uses ferroalloy noble metal enriched slag solution as raw material and adopts the first-of-its-kind "(PtCl4) 2- Selective precipitation - acid dissolution to remove rhodium and palladium" short process technology for efficient purification of platinum, directly preparing platinum metal with purity > 99.99%, and direct recovery rate of platinum > 98%;

[0023] (2) Compared with the existing process, the present invention only needs one round of impurity removal operation to prepare platinum metal with a purity of more than 99.99% for a high-impurity platinum solution, and has the characteristics of fast reaction speed, short process, high direct yield, and low environmental pollution;

[0024] (3) This invention is the first to use a highly selective sulfite complex precipitant in a reduction system to precipitate and separate platinum, effectively solving the problem of (PtCl4) 2- The problem of difficult precipitation separation;

[0025] (4) The present invention utilizes for the first time the difference in solubility of platinum and rhodium in the acid of platinum ammonium sulfite salt precipitation, and controls suitable conditions so that platinum and rhodium can be effectively separated in a reducing system, thereby replacing the traditional hydrolysis process of rhodium removal;

[0026] (5) The process of the present invention is not only suitable for treating materials with less impurity components and higher platinum content, but also can treat materials with more complex impurity components and relatively higher impurity content, and has strong technical adaptability. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited to the described contents.

[0028] Embodiment 1: The solution of the ferroalloy precious metal platinum-enriched slag in this embodiment is a solution obtained by removing a large amount of iron from the ferroalloy containing precious metals through acid dissolution, and then dissolving the acid-insoluble slag after iron removal with aqua regia. The solution mainly contains platinum ions, and also contains a large amount of metal ions including rhodium, palladium, iridium, ruthenium, gold, silver, tin, iron, sodium, potassium, silicon, tungsten, copper, nickel, etc. The main specific components of the solution are shown in Table 1 below:

[0029] Table 1 Content of main components in ferroalloy precious metal platinum-enriched slag solution (g / L)

[0030] ;

[0031] A method for efficiently purifying platinum from ferroalloy precious metal-enriched slag solution in a short process, the specific steps are as follows:

[0032] (1) 200 ml of ferroalloy precious metal enriched slag solution was measured, 200 ml of water was added for dilution, and a reducing agent (sodium sulfite) was added. The mixture was reacted at 95° C. and stirred at 350 r / min for 80 min. The mixture was cooled to room temperature and solid-liquid separated to obtain a crude ammonium chloroplatinite solution and an insoluble slag. The amount of sodium sulfite added was 1.1 times the theoretical molar amount of platinum.

[0033] (2) Under the conditions of temperature of 85°C and stirring (350r / min), the pH value of the crude ammonium chloroplatinite solution is adjusted to 6.5 with a sodium hydroxide solution, and then sodium sulfite and ammonium chloride are simultaneously added to the crude ammonium chloroplatinite solution to react for 100 minutes, cooled to 35°C, and solid-liquid separation is performed to obtain hydroxytrisulfite and ammonium platinate slag (containing 17.74g of platinum); the amount of sodium sulfite added is 1.1 times the theoretical molar amount of platinum, and the amount of ammonium chloride added is 0.2 times the theoretical molar amount of platinum;

[0034] (3) Under the conditions of temperature of 95°C and stirring (350r / min), a 6 mol / L hydrochloric acid solution was added to the hydroxytrisulfite-ammonium platinate residue to dissolve and react for 120 min, dimethylglyoxime was added and the reaction was continued for 10 min, and after cooling to room temperature, precipitation was continued for 6 h, and solid-liquid separation was performed to obtain a pure ammonium chloroplatinite solution (containing 17.70 g of platinum); the mass ratio of the hydrochloric acid solution to the hydroxytrisulfite-ammonium platinate was 3:1, and the amount of dimethylglyoxime added was 5 times the theoretical molar amount of palladium;

[0035] (4) At 85°C and stirring (350 r / min), add ammonium chloride and sodium chlorate to the pure ammonium chloroplatinate solution, and use hydrochloric acid to adjust the H +The concentration is 4 mol / L, and the oxidation reaction is carried out until no precipitation is precipitated, so that platinum is precipitated in the form of high-valent ammonium chloroplatinate, cooled and crystallized at a temperature of 25°C, and the solid is separated from the liquid, and the solid is washed with an acidic ammonium chloride solution A (with a concentration of 2 mol / L and a pH of 0.5) and an ammonium chloride solution B (with a mass concentration of 10%) in sequence to obtain ammonium chloroplatinate; the amount of ammonium chloride added is 1.2 times the theoretical molar amount of platinum, and the amount of sodium chlorate added is 1.2 times the theoretical molar amount of platinum;

[0036] (5) Pure water was added to ammonium chloroplatinate to make a slurry. Hydrazine hydrate was slowly added under stirring conditions of 85°C and 350 r / min. The pH value of the slurry was controlled to 6 with sodium hydroxide solution. The reaction was continued for 10 min after the solution became clear. The solution was cooled to room temperature and solid-liquid separation was performed to obtain platinum powder. The platinum powder was washed with deionized water and added to 3 mol / L hydrochloric acid and boiled for 18 min. The solution was cooled to room temperature and solid-liquid separation was performed. The solid was washed with deionized water until it was neutral and calcined at 700°C for 120 min to obtain refined platinum (17.68 g).

[0037] The impurity content in the refined platinum of this embodiment is shown in Table 2;

[0038] Table 2 Impurity content in refined platinum

[0039] ;

[0040] The purity of refined platinum in this embodiment is >99.99%, and the direct recovery rate of platinum is 98.28%.

[0041] Embodiment 2: The solution of the ferroalloy precious metal platinum-enriched slag in this embodiment is a solution obtained by removing a large amount of iron from the ferroalloy containing precious metals by acid dissolution, and then dissolving the acid-insoluble slag after iron removal with aqua regia. The solution mainly contains platinum ions, and also contains a large amount of metal ions including rhodium, palladium, iridium, ruthenium, gold, silver, tin, iron, sodium, potassium, silicon, tungsten, copper, nickel, etc. The specific contents of the main components in the solution are shown in Table 3 below:

[0042] Table 3 Content of main components in ferroalloy precious metal platinum-enriched slag solution (g / L)

[0043] ;

[0044] A method for efficiently purifying platinum from ferroalloy precious metal-enriched slag solution in a short process, the specific steps are as follows:

[0045] (1) Add 200 ml of water to 200 ml of ferroalloy precious metal enriched slag solution for dilution, add a reducing agent (oxalic acid), carry out reduction reaction at 85°C and stirring (300 r / min) for 110 min, cool to room temperature, and separate the solid and liquid to obtain a crude ammonium chloroplatinite solution and an insoluble slag; the amount of oxalic acid added is 1.3 times the theoretical molar amount of platinum;

[0046] (2) Under the conditions of temperature of 90°C and stirring (300r / min), the pH value of the crude ammonium chloroplatinite solution is adjusted to 7.5 with a sodium hydroxide solution, and then sodium bisulfite and ammonium sulfate are simultaneously added to the crude ammonium chloroplatinite solution to react for 90 minutes, cooled to 40°C, and solid-liquid separation is performed to obtain hydroxytrisulfite and ammonium platinate slag (containing 22.54g of platinum); the amount of sodium bisulfite added is 1.2 times the theoretical molar amount of platinum, and the amount of ammonium sulfate added is 0.3 times the theoretical molar amount of platinum;

[0047] (3) Under the conditions of temperature of 90°C and stirring (300r / min), a 4 mol / L hydrochloric acid solution was added to the hydroxytrisulfurous acid and ammonium platinate residue to dissolve and react for 60 minutes, dimethylglyoxime was added and the reaction was continued for 15 minutes, and after cooling to room temperature, the precipitation reaction was continued for 8 hours, and the solid-liquid separation was performed to obtain a pure ammonium chloroplatinite solution (containing 22.45 g of platinum); the mass ratio of the hydrochloric acid solution to the ammonium platinum sulfite residue was 4:1, and the amount of dimethylglyoxime added was 6 times the theoretical molar amount of palladium;

[0048] (4) At 90°C and stirring (300 r / min), add ammonium chloride and hydrogen peroxide to the pure ammonium chloroplatinate solution, and adjust the H + The concentration is 5 mol / L, and the oxidation reaction is carried out until no precipitation is precipitated, so that platinum is precipitated in the form of high-valent ammonium chloroplatinate, cooled and crystallized at a temperature of 40°C, and the solid is separated from the liquid, and the solid is washed with an acidic ammonium chloride solution A (with a concentration of 3 mol / L and a pH of 0.4) and an ammonium chloride solution B (with a mass concentration of 15%) in sequence to obtain ammonium chloroplatinate; the amount of ammonium chloride added is 1.3 times the theoretical molar amount of platinum, and the amount of hydrogen peroxide added is 1.25 times the theoretical molar amount of platinum;

[0049] (5) Add pure water to ammonium chloroplatinate to make a slurry (the amount of pure water added is 4 times the mass of ammonium chloroplatinate), slowly add hydrazine hydrochloride at 90°C and stirring (300r / min), use sodium hydroxide solution to control the pH value of the slurry to 6, react until the solution is clear and continue to react for 15 minutes, cool to room temperature, separate the solid and liquid to obtain platinum powder, wash the platinum powder with deionized water, add it to dilute hydrochloric acid (concentration of 4 mol / L) and boil it for 15 minutes, cool to room temperature, separate the solid and liquid, wash the solid with deionized water until it is neutral, and calcine at 600°C for 180 minutes to obtain refined platinum (22.38g);

[0050] The impurity content in the refined platinum of this embodiment is shown in Table 4 below:

[0051] Table 4 Impurity content in refined platinum

[0052] ;

[0053] The purity of refined platinum in this embodiment is greater than 99.99%, and the direct recovery rate of platinum is 98.16%.

[0054] Embodiment 3: The solution of the ferroalloy precious metal platinum-enriched slag in this embodiment is a solution obtained by removing a large amount of iron from the ferroalloy containing precious metals through acid dissolution, and then dissolving the acid-insoluble slag after iron removal with aqua regia. The solution mainly contains platinum ions, and also contains a large amount of metal ions including rhodium, palladium, iridium, ruthenium, gold, silver, tin, iron, sodium, potassium, silicon, tungsten, copper, nickel, etc. The contents of the main components in the specific solution are shown in Table 5 below:

[0055] Table 5 Main component contents of ferroalloy precious metal platinum enriched slag solution (g / L)

[0056] ;

[0057] A method for efficiently purifying platinum from ferroalloy precious metal-enriched slag solution in a short process, the specific steps are as follows:

[0058] (1) 200 ml of ferroalloy precious metal enriched slag solution was measured, 200 ml of water was added for dilution, hydrazine hydrochloride was added, reduction reaction was carried out at 90° C. and stirring (250 r / min) for 120 min, the solution was cooled to room temperature, and solid-liquid separation was performed to obtain a crude ammonium chloroplatinite solution and an insoluble slag; the amount of hydrazine hydrochloride added was 1.2 times the theoretical molar amount of platinum;

[0059] (2) Under the conditions of temperature of 100° C. and stirring (250 r / min), the pH value of the crude ammonium chloroplatinite solution is adjusted to 4.5 with a sodium hydroxide solution, and then ammonium sulfite and ammonium bicarbonate are simultaneously added to the crude ammonium chloroplatinite solution to react for 70 minutes, cooled to 50° C., and solid-liquid separation is performed to obtain ammonium hydroxytrisulfite with platinum (containing 24.82 g of platinum); the amount of ammonium sulfite added is 1.4 times the theoretical molar amount of platinum, and the amount of ammonium bicarbonate added is 0.15 times the theoretical molar amount of platinum;

[0060] (3) Under the conditions of temperature of 95°C and stirring (250r / min), a 3 mol / L hydrochloric acid solution was added to the hydroxytrisulfurous acid and ammonium platinate residue to dissolve and react for 70 minutes, dimethylglyoxime was added and the reaction was continued for 12 minutes, and after cooling to room temperature, precipitation was continued for 5 hours, and solid-liquid separation was performed to obtain a pure ammonium chloroplatinite solution (containing 24.78 g of platinum); the mass ratio of the hydrochloric acid solution to the ammonium platinum sulfite residue was 5:1, and the amount of dimethylglyoxime added was 7 times the theoretical molar amount of palladium;

[0061] (4) At 95°C and stirring (250 r / min), add ammonium chloride to the pure ammonium chloroplatinite solution, introduce chlorine gas for oxidation, and use hydrochloric acid to adjust the H +The concentration is 3 mol / L, and the oxidation reaction is carried out until no precipitation is precipitated, so that platinum is precipitated in the form of high-valent ammonium chloroplatinate, cooled and crystallized at a temperature of 45°C, and the solid is separated from the liquid, and the solid is washed with an acidic ammonium chloride solution A (with a concentration of 3 mol / L and a pH of 0.6) and an ammonium chloride solution B (with a mass concentration of 20%) in sequence to obtain ammonium chloroplatinate; the amount of ammonium chloride added is 1.5 times the theoretical molar amount of platinum, and the amount of chlorine gas introduced is 1.3 times the theoretical molar amount of platinum;

[0062] (5) Add pure water to ammonium chloroplatinate to make a slurry, slowly add hydrazine hydrochloride at 85°C and stirring (250r / min), use sodium hydroxide solution to control the pH value of the slurry to 6, react until the solution is clear and continue to react for 18 minutes, cool to room temperature, separate the solid and liquid to obtain platinum powder, wash the platinum powder with deionized water, add it to dilute hydrochloric acid (concentration of 5 mol / L) and boil it for 12 minutes, cool to room temperature, separate the solid and liquid, wash the solid with deionized water until it is neutral, and calcine at 650°C for 160 minutes to obtain refined platinum (24.70g);

[0063] The impurity content in the refined platinum of this embodiment is shown in Table 6;

[0064] Table 6 Impurity content in refined platinum

[0065] ;

[0066] The purity of refined platinum in this embodiment is greater than 99.99%, and the direct recovery rate of platinum is 98.01%.

[0067] The specific implementation modes of the present invention are described in detail above, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for efficiently purifying platinum from ferroalloy precious metal-enriched slag solution in a short process, characterized in that: The specific steps are as follows: (1) Add water in an equal volume ratio to dilute the ferroalloy precious metal enriched slag solution, add a reducing agent, react at a temperature of 80-100°C for 60-120 minutes, and separate the solid and liquid to obtain a crude ammonium chloroplatinite solution and an insoluble slag; (2) Under stirring conditions at a temperature of 80 to 100° C., adjusting the pH value of the crude ammonium chloroplatinite solution to 4.5 to 8, then adding a sulfite platinum complexing agent and an ammonium salt to the crude ammonium chloroplatinite solution simultaneously for a reaction of 60 to 90 minutes, and obtaining a hydroxytrisulfite-ammonium platinum slag after cooling and solid-liquid separation; the sulfite platinum complexing agent is one or more of sodium sulfite, sodium bisulfite, ammonium bisulfite, and ammonium sulfite; the ammonium salt is one or more of ammonium chloride, ammonium sulfate, and ammonium bicarbonate; the amount of the sulfite platinum complexing agent added is 1.1 to 1.5 times the theoretical molar amount of platinum, and the amount of the ammonium salt added is 0.1 to 0.3 times the theoretical molar amount of platinum; (3) At a temperature of 80-100°C and under stirring conditions, add the acid solution to the hydroxytrisulfurous acid and ammonium platinate residue, dissolve and react for 60-120 minutes, add diacetyl oxime and continue to react for 10-20 minutes, cool to room temperature and continue to precipitate for 4-8 hours, and separate the solid and liquid to obtain a pure ammonium chloroplatinite solution; (4) Add the ammonium salt and oxidant to the pure ammonium chloroplatinate solution at a temperature of 80-100°C and stirring, and adjust the H + The concentration is 3-6 mol / L, the oxidation reaction is carried out until no precipitation is formed, cooling and crystallization are carried out, solid-liquid separation is carried out, and the solid is washed with acidic ammonium chloride solution A and ammonium chloride solution B in sequence to obtain ammonium chloroplatinate solid; (5) Pure water is added to the ammonium chloroplatinate solid to make it slurry. A reducing agent is slowly added at a temperature of 80-100°C with stirring. The pH value of the slurry is controlled at 6-7 with a sodium hydroxide solution. The solution is reacted until it becomes clear. The solution is cooled to room temperature and the solid-liquid separation is performed to obtain platinum powder. The platinum powder is added to dilute hydrochloric acid and boiled for 10-20 min. The solution is cooled to room temperature and the solid-liquid separation is performed. The solid is washed with pure water until it is neutral and calcined at a temperature of 600-700°C for 120-180 min to obtain refined platinum.

2. The method for efficiently purifying platinum from ferroalloy noble metal-enriched slag solution in a short process according to claim 1, characterized in that: The ferroalloy precious metal enriched slag solution in step (1) contains 50-120 g / L of platinum ions and two or more metal impurity ions selected from rhodium, palladium, iridium, ruthenium, silver, gold, tin, iron, sodium, potassium, silicon, tungsten and copper.

3. The method for efficiently purifying platinum from ferroalloy noble metal-enriched slag solution in a short process according to claim 1, characterized in that: The reducing agent in step (1) is one or more of oxalic acid, oxalate, hydrazine hydrate, hydrazine hydrochloride, and sulfite, and the amount of the reducing agent added is 1.1 to 1.3 times the theoretical molar amount of platinum.

4. The method for efficiently purifying platinum from ferroalloy noble metal-enriched slag solution in a short process according to claim 1, characterized in that: The acid solution in step (3) is dilute hydrochloric acid or dilute sulfuric acid, the concentration of dilute hydrochloric acid is 3-6 mol / L, and the concentration of dilute sulfuric acid is 3-6 mol / L; the mass ratio of the acid solution to hydroxytrisulfite and ammonium platinate is 3-5:1, and the amount of dimethylglyoxime added is 5-10 times the theoretical molar amount of palladium.

5. The method for efficiently purifying platinum from ferroalloy noble metal-enriched slag solution in a short process according to claim 1, characterized in that: In step (4), the ammonium salt is ammonium chloride, the amount of ammonium salt added is 1.2 to 1.5 times the theoretical molar amount of platinum, and the amount of oxidant added is 1.2 to 1.3 times the theoretical molar amount of platinum; the oxidant is sodium chlorate, hydrogen peroxide, sodium hypochlorite, perchloric acid or chlorine gas.

6. The method for efficiently purifying platinum from ferroalloy noble metal-enriched slag solution in a short process according to claim 1, characterized in that: The temperature of cooling crystallization in step (4) is 25-50° C., the concentration of the acidic ammonium chloride solution A is 2-3 mol / L, the pH is 0.4-0.6, and the mass concentration of the ammonium chloride solution B is 10-20%.

7. The method for efficiently purifying platinum from ferroalloy noble metal-enriched slag solution in a short process according to claim 1, characterized in that: The amount of pure water added in step (5) is 3 to 10 times the mass of ammonium chloroplatinate.

8. The method for efficiently purifying platinum from ferroalloy noble metal-enriched slag solution in a short process according to claim 1, characterized in that: The reducing agent in step (5) is hydrazine hydrate or hydrazine hydrochloride, and the amount of the reducing agent added is 1.1 to 1.3 times the theoretical molar amount of platinum.

9. The method for efficiently purifying platinum from ferroalloy noble metal-enriched slag solution in a short process according to claim 1, characterized in that: The concentration of dilute hydrochloric acid in step (5) is 3-5 mol / L, and the mass ratio of platinum powder to dilute hydrochloric acid is 1:5-10.