Method for enriching precious metal from nickel anode slime desulfurization tailings

Abstract

The invention belongs to the technical field of precious metal hydrometallurgy, and particularly relates to a method for enriching precious metal from nickel anode slime desulfurized tailings, which comprises the following steps: combining sodium sulfite with elemental sulfur in the nickel anode slime desulfurized tailings to realize 98% removal of elemental sulfur in the nickel anode slime desulfurized tailings; meanwhile, a high-quality sodium thiosulfate product can be obtained, and the goal of zero discharge of alkaline wastewater is achieved. By means of the method, the direct recovery rate of gold, platinum and palladium precious metal (namely, the mass content of the precious metal in the finally obtained concentrate accounts for the mass content of the precious metal in the nickel anode mud desulfurization tailings) is larger than 99%, the grade of the finally obtained concentrate is high, the content of gold, platinum and palladium reaches up to 10-15%, and the concentrate can directly enter the extraction separation refining procedure. The full-wet process flow is adopted, the environment is good, the labor intensity is low, the efficiency is high, the production process is easy to control, and the automation of the operation process is easy to realize.

Description

Technical Field

[0001] The invention belongs to the technical field of precious metal hydrometallurgy, and in particular relates to a method for enriching precious metals from desulfurization tailings of nickel anode mud. Background Art

[0002] Nickel anode mud desulfurization tailings are a kind of metallurgical intermediate product containing precious metals after the nickel anode mud is heated and filtered to remove sulfur. The chemical composition range of nickel anode mud desulfurization tailings is roughly Ni12%, Cu6%, Fe1.6%, Co0.3%, S78.2%, SiO20.4%, Au55g / t, Pd79g / t, Pt81g / t, Rh5g / t, Ir3g / t, Ru9g / t, Ag90g / t. There are currently three processing processes for this material. Process 1: Melting in a reverberatory furnace, casting into anode plates for electrolysis, precious metals are enriched in the secondary anode mud, and sulfur and base metals are leached under pressure, and precious metals are enriched in the slag. , the precious metal content is 5%, and the enriched materials enter the extraction process for separation and purification; Process 2: Use the nickel anode mud desulfurization tailings as a sulfiding agent to sulfide the primary Cu-Ni alloy, and then smelt to produce secondary Cu-Ni high matte, finely grind and magnetically separate as the secondary alloy for extracting precious metals, and then control electrochlorination, desulfurization, and secondary chlorination to form a concentrate with a precious metal content of 10%, and enter the extraction process for separation and purification; Process 3: Use vacuum distillation for desulfurization, smelting and slag making, controlled electrochlorination to leach base metals, and the enriched material is incorporated into the primary Cu-Ni alloy, enter the main process of extracting precious metals, and produce 9% precious metal concentrate, and then enter the extraction process for separation and purification. The above processes all have the problems of long process flow, complicated operation, and serious loss of precious metals. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a method for enriching precious metals from nickel anode mud desulfurization tailings, and the present invention specifically includes the following contents:

[0004] A method for enriching precious metals from nickel anode mud desulfurization tailings comprises the following steps:

[0005] S1, primary desulfurization: slurry the nickel anode mud desulfurization tailings according to the solid-liquid mass ratio of 1: (0.7-1.5), then heat to 90-110 ° C and keep warm for a period of time; then add alkaline solution to the slurry to adjust the pH to 8-10; then add sodium sulfite solution to react at a reaction temperature of 95-105 ° C to obtain sodium thiosulfate solution and primary desulfurization slag;

[0006] S2, one-stage controlled electrochlorination: the primary desulfurization slag and hydrochloric acid with a concentration of 2-3 mol / L are mixed at a solid-liquid ratio of 1:(4-5) to obtain a mixed liquid, chlorine gas is introduced into the mixed liquid to increase the potential of the reaction system to 150-350 mV, and a one-stage controlled electrochlorination reaction is performed to obtain a first-stage liquid;

[0007] S3, two-stage controlled electro-chlorination: chlorine gas is introduced into the first-stage feed liquid to increase the potential of the reaction system to 395-405 mV, and a two-stage controlled electro-chlorination reaction is performed to obtain controlled electro-chlorination slag;

[0008] S4, secondary desulfurization: the electro-chlorination slag is slurried at a solid-liquid mass ratio of 1:(3-5), then heated to 90-110°C and kept warm for a period of time, the pH is adjusted to 8-10, and then a sodium sulfite solution is added to react at a reaction temperature of 95-105°C. After the reaction is completed, a sodium thiosulfate solution and a precious metal concentrate are obtained.

[0009] Furthermore, the insulation time in step S1 is 5-20 minutes.

[0010] Furthermore, the temperature of the sodium sulfite solution in step S1 is 85-95° C.; and / or, the ratio of the mass of the nickel anode mud desulfurization tailings in step S1 to the volume of the added sodium sulfite solution is 1:(4-5), and the mass of the added sodium sulfite is 4-4.5 times the mass of sulfur in the nickel anode mud desulfurization tailings; and / or, the reaction time in step S1 is 10-20 min, and the reaction time is kept warm for 8-15 min after the reaction time ends.

[0011] Furthermore, the reaction temperature of the two-stage controlled electrochlorination in step S3 is 90-100°C.

[0012] Furthermore, the one-stage controlled electrochlorination and / or the two-stage controlled electrochlorination reaction is a stirring reaction, and the stirring speed is 20-30 rpm.

[0013] Furthermore, the total reaction time of the first stage controlled electro-chlorination and the second stage controlled electro-chlorination is 8-15h.

[0014] Furthermore, the total mass content of gold, platinum and palladium in the precious metal concentrate is 10-15%.

[0015] The present invention firstly slurries the nickel anode mud desulfurization tailings with hot water, then heats and boils them for a period of time, then uses sodium hydroxide to adjust the pH value of the liquid, and then adds a prepared high-temperature sodium sulfite solution according to the sulfur content in the nickel anode mud desulfurization tailings, heats and reacts at a constant temperature, and the main reaction formula is Na2SO3+S=Na2S2O3, thereby achieving the purpose of one-time desulfurization.

[0016] Next, the primary desulfurization slag hydrochloric acid system is put into the system, by controlling the amount of chlorine gas introduced, controlling and maintaining the potential of the liquid, and performing a two-stage controlled electrochlorination reaction, so that the base metals in the nickel anode mud desulfurization tailings undergo oxidation reaction and enter the solution, while the precious metals do not react and remain in the slag, thereby achieving the purpose of separating the precious and base metals. The main reactions in this step include:

[0017] Ni+2HCl=NiCl2+H2↑

[0018] Ni+Cl2=NiCl2

[0019] Cu+Cl2=CuCl2

[0020] Ni+2CuCl2=NiCl2+2CuCl

[0021] 2CuCl+Cl2=2CuCl2

[0022] CuS+Cl2=CuCl2+S↓

[0023] NiS+Cl2=NiCl2+S↓

[0024] Finally, the electrochlorination slag is slurried at a solid-liquid mass ratio of 1:(3-5), then heated and kept warm, the pH is adjusted, and then a sodium sulfite solution is added to react. The main function of this step is to further remove the elemental sulfur produced in the second step.

[0025] Beneficial effects of the present invention:

[0026] The method for enriching precious metals in nickel anode mud desulfurization tailings disclosed in the present invention adopts sodium sulfite to combine with elemental sulfur in nickel anode mud desulfurization tailings to achieve 98% removal of elemental sulfur in nickel anode mud desulfurization tailings. While sulfur and precious metals are efficiently separated, high-quality sodium thiosulfate products can also be obtained at the same time, and the goal of zero discharge of alkaline wastewater is achieved. The entire operation process is simple and effective. Compared with incineration desulfurization and other desulfurization methods, it has the advantages of short process flow and high precious metal recovery rate. The direct recovery rate of gold, platinum and palladium precious metals (that is, the content of precious metals in the final concentrate accounts for the mass content of precious metals in the nickel anode mud desulfurization tailings) of the method is greater than 99%, and the final concentrate is of high grade, with gold, platinum and palladium contents as high as 10-15%, which can directly enter the extraction separation and refining process. This invention adopts a full wet process flow, which has a good environment, low labor intensity, high efficiency, easy control of the production process, and easy to realize the automation of the operation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The process flow chart of the method disclosed in the present invention is shown in FIG. DETAILED DESCRIPTION

[0028] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments shown below do not limit the invention content described in the claims. In addition, the entire contents of the structures represented by the following embodiments are not limited to those necessary as solutions to the invention described in the claims.

[0029] Reference Figure 1, a method for enriching precious metals from nickel anode mud desulfurization tailings, comprising the following steps:

[0030] S1, primary desulfurization: the nickel anode mud desulfurization tailings are slurried with hot water according to a solid-liquid mass ratio of 1: (0.7-1.5), and then heated to 90-110 ° C to boil the slurry for 5-20 minutes; then a liquid alkali solution is added to the slurry in small amounts and multiple times, the amount of liquid alkali solution added is 3-10L, and the pH is adjusted to 8-10; then a sodium sulfite solution at a temperature of 85-95 ° C is added for reaction, and the mass ratio of the nickel anode mud desulfurization tailings to the volume of the added sodium sulfite solution is 1: :(4-5), control the mass of the added sodium sulfite to be 4-4.5 times the mass of the sulfur in the nickel anode mud desulfurization tailings, the excess coefficient is about 1-1.3, heat to a temperature of 95-105 ° C to make the reaction system boil for reaction, the reaction time is 10-20min, after the reaction time is over, keep warm for 8-15min, then immediately perform filter pressing, slurry washing, solid-liquid separation to avoid gold loss, obtain filtrate and primary desulfurization slag, the filtrate is used for refined sodium thiosulfate;

[0031] S2, one-stage controlled electro-chlorination: the primary desulfurization slag and hydrochloric acid with a concentration of 2-3 mol / L are mixed at a solid-liquid ratio of 1:(4-5) to obtain a mixed liquid, chlorine gas is introduced into the mixed liquid to raise the potential of the reaction system to 150-350 mV, and a one-stage controlled electro-chlorination reaction is performed. Stirring is started at the same time, and the stirring speed is controlled to be 20-30 rpm to obtain a first-stage liquid;

[0032] S3, two-stage controlled electro-chlorination: chlorine gas is introduced into the first-stage liquid to increase the potential of the reaction system to 395-405mV, and a two-stage controlled electro-chlorination reaction is carried out at a reaction temperature of 90-100°C. Stirring is started during the reaction, and the stirring speed is controlled to be 20-30 rpm. The total reaction time of the first-stage controlled electro-chlorination and the second-stage controlled electro-chlorination is controlled to be 8-15h, and finally the controlled electro-chlorination slag is obtained;

[0033] S4, secondary desulfurization: the electro-chlorination slag is slurried at a solid-liquid mass ratio of 1:(3-5), then heated to 90-110°C and kept warm for a period of time, the pH is adjusted to 8-10, and then a sodium sulfite solution is added to react at a reaction temperature of 95-105°C. After the reaction, a sodium thiosulfate solution and a precious metal concentrate are obtained. The direct recovery rate of precious metals by this method is more than 99%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 10-15%.

[0034] Example 1

[0035] A method for enriching precious metals from nickel anode mud desulfurization tailings comprises the following steps:

[0036] S1, primary desulfurization: first add 0.3-0.5m 3 of hot water, start stirring; each kettle (3m 3 ) Add 400±10kg of nickel anode mud desulfurization tailings, slurry and heat to boiling; keep boiling for 10 minutes, then add liquid alkali solution in small amounts and multiple times, stir and sample to detect pH, add about 3-10L, when the pH of the liquid is 9, stop adding liquid alkali solution; then add the prepared high-temperature sodium sulfite solution above 90°C (1000-2000kg / kettle), the solid-liquid ratio of sodium sulfite solution to material (the solid-liquid ratio refers to the ratio of solid mass to liquid volume, the same below) is 1:4.5, the amount of sodium sulfite added is 4 times the sulfur content in the nickel anode mud desulfurization tailings, and the excess coefficient is 1.15, the boiling reaction time is 15min, and the constant temperature time is 10min. Immediately perform filter pressing, slurry washing and separation to avoid gold loss, the filtrate is used for refined sodium thiosulfate, and the filter residue enters the electric chlorination control station;

[0037] S2, one-stage controlled electric chlorination: the desulfurization slag produced above is fed into a mechanical kettle (Ф1600*6000) by a screw feeder (screw feed 24 rpm), and 2.5 mol / L hydrochloric acid solution is added at a solid-liquid ratio of 1:4.5. After stirring, the chlorine valve is slowly opened to pass into the mechanical kettle liquid; when the potential of the first cell is raised to 150-350 mV, the stirring of the 2nd, 3rd and 4th cells is opened in sequence;

[0038] S3, two-stage controlled electric chlorination: let the feed liquid flow from the first stage into the four cells of the second stage in sequence, ensure that the potential of the feed liquid in the four cells of the second stage is between 395 and 405mv, and the reaction temperature is 90-100℃. During the operation, the potential is tested on site and calibrated with the potential displayed on the computer every 1-2 hours, and the potential and the chlorine valve are controlled by computer to form a chain system to ensure constant potential. After chlorination for more than 10 hours, the material is filtered and separated by pressure, and the filtrate is returned to the nickel system for nickel refining. After the filter residue is slurried and washed and purged with high-pressure wind, the washing water is mixed with acid for chlorination, and the filter residue enters the secondary desulfurization;

[0039] S4, secondary desulfurization: The method is the same as the primary desulfurization, each kettle processes 400±10kg of controlled electrochlorination slag, except that the solid-liquid ratio is changed to 1:4. Other technical conditions remain unchanged. The sulfur produced by controlled electrochlorination can be removed again, and the desulfurization operation is exactly the same as the first time. After the secondary desulfurization, the filtrate is pressed and separated, and the filtrate is used together with the primary desulfurization liquid to produce a refined sodium thiosulfate product. The filter residue is slurried and washed to neutrality, and is used as a concentrate for extraction and separation to purify platinum, palladium and gold. The direct recovery rate of precious metals is more than 99%, and the total mass content of gold, platinum and palladium in the concentrate is 10-15%.

[0040] Example 2

[0041] A method for enriching precious metals from nickel anode mud desulfurization tailings comprises the following steps:

[0042] S1, primary desulfurization: the nickel anode mud desulfurization tailings are slurried with hot water at a solid-liquid mass ratio of 1:0.7, and then heated to 90°C to boil the slurry for 5 minutes; then a liquid alkali solution is added to the slurry in small amounts and multiple times, the amount of the liquid alkali solution added is 3.5L, and the pH is adjusted to 8; then a sodium sulfite solution at a temperature of 85°C is added for reaction, the solid-liquid mass ratio of the nickel anode mud desulfurization tailings to the added sodium sulfite solution is 1:4, the mass of the added sodium sulfite is controlled to be 4.1 times the mass of sulfur in the nickel anode mud desulfurization tailings, and the excess coefficient is about 1.1, and the temperature is heated to 98°C to boil the reaction system for reaction, the reaction time is 10 minutes, and the reaction time is kept warm for 8 minutes, and then filter pressing, slurry washing, solid-liquid separation are immediately performed to avoid gold loss, and a filtrate and primary desulfurization slag are obtained, and the filtrate is used for refining sodium thiosulfate;

[0043] S2, one-stage controlled electrochlorination: the primary desulfurization slag and 2 mol / L hydrochloric acid are mixed at a solid-liquid ratio of 1:4 to obtain a mixed liquid, chlorine gas is introduced into the mixed liquid to raise the potential of the reaction system to 150 mV, and a one-stage controlled electrochlorination reaction is performed. Stirring is started at the same time, and the stirring speed is controlled to be 20 rpm to obtain a first-stage liquid;

[0044] S3, two-stage controlled electro-chlorination: chlorine gas is introduced into the first-stage liquid, the potential of the reaction system is raised to 395 mV, and a two-stage controlled electro-chlorination reaction is carried out. The reaction temperature is 90°C, stirring is started at the same time, and the stirring speed is controlled to 20 rpm. The total reaction time of the first-stage controlled electro-chlorination and the second-stage controlled electro-chlorination is controlled to be 9 hours, and finally the controlled electro-chlorination slag is obtained;

[0045] S4, secondary desulfurization: the electro-chlorination slag is slurried at a solid-liquid mass ratio of 1:3, then heated to 90°C for a period of time, the pH is adjusted to 8, and then a sodium sulfite solution is added to react at a reaction temperature of 95°C. After the reaction, a sodium thiosulfate solution and a precious metal concentrate are obtained. According to testing, the direct recovery rate of the precious metals in this embodiment is more than 99.1%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 11.2%.

[0046] Example 3

[0047] A method for enriching precious metals from nickel anode mud desulfurization tailings comprises the following steps:

[0048] S1, primary desulfurization: the nickel anode mud desulfurization tailings are slurried with hot water at a solid-liquid mass ratio of 1:1.45, and then heated to 110°C to boil the slurry for 20 minutes; then a liquid alkali solution is added to the slurry in small amounts and multiple times, the amount of the liquid alkali solution added is 9.7L, and the pH is adjusted to 10; then a sodium sulfite solution at a temperature of 95°C is added for reaction, the solid-liquid mass ratio of the nickel anode mud desulfurization tailings to the added sodium sulfite solution is 1:5, the mass of the added sodium sulfite is controlled to be 4.5 times the mass of sulfur in the nickel anode mud desulfurization tailings, and the excess coefficient is about 1.5, and the temperature is heated to 105°C to boil the reaction system for reaction, the reaction time is 20 minutes, and the reaction time is kept warm for 15 minutes, and then filter pressing, slurry washing, solid-liquid separation are immediately performed to avoid gold loss, and filtrate and primary desulfurization slag are obtained, and the filtrate is used for refining sodium thiosulfate;

[0049] S2, one-stage controlled electrochlorination: the primary desulfurization slag and 3 mol / L hydrochloric acid are mixed at a solid-liquid ratio of 1:5 to obtain a mixed liquid, chlorine gas is introduced into the mixed liquid to raise the potential of the reaction system to 350 mV, and a one-stage controlled electrochlorination reaction is performed. Stirring is started at the same time, and the stirring speed is controlled to 30 rpm to obtain a first-stage liquid;

[0050] S3, two-stage controlled electro-chlorination: chlorine gas is introduced into the first-stage feed liquid, the potential of the reaction system is increased to 405mV, and a two-stage controlled electro-chlorination reaction is carried out. The reaction temperature is 100°C, stirring is started at the same time, and the stirring speed is controlled to 30 rpm. The total reaction time of the first-stage controlled electro-chlorination and the second-stage controlled electro-chlorination is controlled to be 15h, and finally the controlled electro-chlorination slag is obtained;

[0051] S4, secondary desulfurization: the electro-chlorination slag is slurried at a solid-liquid mass ratio of 1:5, then heated to 110°C for a period of time, the pH is adjusted to 10, and then a sodium sulfite solution is added to react at a reaction temperature of 105°C. After the reaction, a sodium thiosulfate solution and a precious metal concentrate are obtained. According to testing, the direct recovery rate of the precious metals in this embodiment is 99.3%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 13.8%.

[0052] Example 4

[0053] A method for enriching precious metals from nickel anode mud desulfurization tailings comprises the following steps:

[0054] S1, primary desulfurization: the nickel anode mud desulfurization tailings are slurried with hot water at a solid-liquid mass ratio of 1:1.2, and then heated to 100°C to boil the slurry for 10 minutes; then a liquid alkali solution is added to the slurry in small amounts and multiple times, the amount of the liquid alkali solution added is 5.4L, and the pH is adjusted to 9; then a sodium sulfite solution at a temperature of 90°C is added for reaction, the solid-liquid mass ratio of the nickel anode mud desulfurization tailings to the added sodium sulfite solution is 1:4.5, the mass of the added sodium sulfite is controlled to be 4.3 times the mass of sulfur in the nickel anode mud desulfurization tailings, and the excess coefficient is about 1.2, and the temperature is heated to 100°C to boil the reaction system for reaction, the reaction time is 15 minutes, and the reaction time is kept warm for 10 minutes after the reaction time ends, and then filter pressing, slurry washing, solid-liquid separation are immediately performed to avoid gold loss, and filtrate and primary desulfurization slag are obtained, and the filtrate is used for refining sodium thiosulfate;

[0055] S2, one-stage controlled electrochlorination: the primary desulfurization slag and 2.5 mol / L hydrochloric acid are mixed at a solid-liquid ratio of 1:4.5 to obtain a mixed liquid, chlorine is introduced into the mixed liquid to raise the potential of the reaction system to 250-330 mV, and a one-stage controlled electrochlorination reaction is performed. Stirring is started at the same time, and the stirring speed is controlled to be 25 rpm to obtain a first-stage liquid;

[0056] S3, two-stage controlled electro-chlorination: chlorine gas is introduced into the first-stage liquid to increase the potential of the reaction system to 395-405mV, and a two-stage controlled electro-chlorination reaction is carried out. The reaction temperature is 95°C, stirring is started at the same time, and the stirring speed is controlled to 25 rpm. The total reaction time of the first-stage controlled electro-chlorination and the second-stage controlled electro-chlorination is controlled to be 10h, and finally the controlled electro-chlorination slag is obtained;

[0057] S4, secondary desulfurization: the electro-chlorination slag is slurried at a solid-liquid mass ratio of 1:4, then heated to 100°C for a period of time, the pH is adjusted to 9, and then a sodium sulfite solution is added to react at a reaction temperature of 100°C. After the reaction, a sodium thiosulfate solution and a precious metal concentrate are obtained. According to testing, the direct recovery rate of the precious metals in this embodiment is 99.6%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 14.9%.

[0058] Example 5

[0059] The method of the present invention is used to treat 40 tons of nickel anode mud desulfurization tailings (composition Ni 14%, Cu 7%, Fe 1.2%, Co 0.4%, S 75.2%, SiO 2 0.5%, Au 59g / t, Pd 83g / t, Pt 89g / t, Rh 9g / t, Ir 9g / t, Ru 10g / t, Ag 96g / t), and after primary desulfurization, controlled electrochlorination, and secondary desulfurization, 72.31 kg of concentrate with a grade of 12.73% of precious metals platinum, palladium, and gold is obtained, wherein the contents of gold, palladium, and platinum are 3.54kg, 3.31kg, and 2.35kg, respectively. The direct recovery rate of precious metals in this embodiment is more than 99%, and 138.9 tons of sodium thiosulfate are output, with a direct recovery rate of 93.5% and a purity of 94.3%.

[0060] Example 6

[0061] The method of the present invention is used to treat 60 tons of nickel anode mud desulfurization tailings (composition Ni 13.7%, Cu 6.5%, Fe 1.1%, Co 0.3%, S 78.2%, SiO 2 0.6%, Au 66g / t, Pd 89g / t, Pt 96g / t, Rh 8g / t, Ir 7g / t, Ru 11g / t, Ag 91g / t), and after one desulfurization, one controlled electrochlorination, and two desulfurization, 114.10 kg of concentrate with a grade of 13.12% of precious metals platinum, palladium, and gold is obtained, wherein the contents of gold, palladium, and platinum are 3.9kg, 5.34kg, and 5.73kg, respectively. The direct recovery rate of precious metals in this embodiment is more than 99.4%, and 216 tons of sodium thiosulfate are output, with a direct recovery rate of 93.15% and a purity of 95.1%.

[0062] Example 7

[0063] This technology is used to treat 80 tons of nickel anode mud desulfurization tailings (composition Ni15.7%, Cu7.2%, Fe1.5%, Co0.4%, S75.2%, SiO20.7%, Au72g / t, Pd92g / t, Pt87g / t, Rh7g / t, Ir6g / t, Ru15g / t, Ag89g / t), after one desulfurization, one controlled electrochlorination, and two desulfurization, 144.10 kg of concentrate with a grade of 12.7% of precious metals platinum, palladium, and gold is obtained, wherein the contents of gold, palladium, and platinum are 5.74 kg, 7.35.kg, and 6.95 kg, respectively. The direct recovery rate of precious metals in this embodiment is more than 99.8%, and 289 tons of sodium thiosulfate are produced, with a direct recovery rate of 97.30% and a purity of 93.87%.

[0064] Comparative Example 1

[0065] The difference between this comparative example and Example 4 is that the solid-liquid ratio of the primary desulfurization slurry is 1:0.5, and the solid-liquid ratio of the secondary desulfurization slurry is 1:6, and other conditions are the same.

[0066] According to the test, the direct recovery rate of the precious metals in this comparative example is 97.3%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 8.8%.

[0067] Comparative Example 2

[0068] The difference between this comparative example and Example 4 is that the solid-liquid ratio of the primary desulfurization slurry is 1:2, and the solid-liquid ratio of the secondary desulfurization slurry is 1:2, and other conditions are the same.

[0069] According to the test, the direct recovery rate of the precious metals in this comparative example is 98.5%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 9.4%.

[0070] Comparative Example 3

[0071] The difference between this comparative example and Example 4 is that the primary desulfurization reaction temperature is 90° C., and other conditions are the same.

[0072] According to the test, the direct recovery rate of the precious metals in this comparative example is 97.9%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 8.3%.

[0073] Comparative Example 4

[0074] The difference between this comparative example and Example 4 is that the solid-liquid ratio of the first-stage controlled electrochlorination is 1:3, and other conditions are the same.

[0075] According to the test, the direct recovery rate of the precious metals in this comparative example is 96.7%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 8.1%.

[0076] Comparative Example 5

[0077] The difference between this comparative example and Example 4 is that the potential of the first stage controlled electrochlorination is 140 mV, and the other conditions are the same.

[0078] According to the test, the direct recovery rate of the precious metals in this comparative example is 96.4%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 8.5%.

[0079] Comparative Example 6

[0080] The difference between this comparative example and Example 4 is that the potential of the first stage controlled electrochlorination is 360 mV, and the other conditions are the same.

[0081] According to the test, the direct recovery rate of the precious metals in this comparative example is 97.9%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 9.4%.

[0082] Comparative Example 7

[0083] The difference between this comparative example and Example 4 is that the potential of the two-stage controlled electrochlorination is 390 mV, and other conditions are the same.

[0084] According to the test, the direct recovery rate of the precious metals in this comparative example is 98.7%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 9.6%.

[0085] Comparative Example 8

[0086] The difference between this comparative example and Example 4 is that the potential of the two-stage controlled electrochlorination is 410 mV, and other conditions are the same.

[0087] According to the test, the direct recovery rate of the precious metals in this comparative example is 98.6%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 9.3%.

[0088] Comparative Example 9

[0089] The difference between this comparative example and Example 4 is that the first-stage controlled electro-chlorination is not performed, and the second-stage controlled electro-chlorination is performed directly, and the other conditions are the same.

[0090] According to the test, the direct recovery rate of the precious metals in this comparative example is 95.8%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 79%.

[0091] Comparative Example 10

[0092] The difference between this comparative example and Example 4 is that the solid-liquid ratio of the secondary desulfurization slurry is 1:2, and other conditions are the same.

[0093] According to the test, the direct recovery rate of the precious metals in this comparative example is 98.5%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 9.1%.

[0094] Comparative Example 11

[0095] The difference between this comparative example and Example 4 is that the solid-liquid ratio of the secondary desulfurization slurry is 1:6, and other conditions are the same.

[0096] According to the test, the direct recovery rate of the precious metals in this comparative example is 98.8%, and the total mass content of gold, platinum and palladium in the precious metal concentrate is 9.5%.

[0097] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for enriching precious metals from nickel anode mud desulfurization tailings, characterized in that: The following steps are involved: S1, primary desulfurization: slurry the nickel anode mud desulfurization tailings according to the solid-liquid mass ratio of 1: (0.7-1.5), then heat to 90-110 ° C and keep warm for a period of time; then add alkaline solution to the slurry to adjust the pH to 8-10; then add sodium sulfite solution to react at a reaction temperature of 95-105 ° C to obtain sodium thiosulfate solution and primary desulfurization slag; S2, one-stage controlled electrochlorination: the primary desulfurization slag and hydrochloric acid with a concentration of 2-3 mol / L are mixed at a solid-liquid ratio of 1:(4-5) to obtain a mixed liquid, chlorine gas is introduced into the mixed liquid to increase the potential of the reaction system to 150-350 mV, and a one-stage controlled electrochlorination reaction is performed to obtain a first-stage liquid; S3, two-stage controlled electro-chlorination: chlorine gas is introduced into the first-stage feed liquid to increase the potential of the reaction system to 395-405 mV, and a two-stage controlled electro-chlorination reaction is performed to obtain controlled electro-chlorination slag; S4, secondary desulfurization: the electro-chlorination slag is slurried at a solid-liquid mass ratio of 1:(3-5), then heated to 90-110°C and kept warm for a period of time, the pH is adjusted to 8-10, and then a sodium sulfite solution is added to react at a reaction temperature of 95-105°C. After the reaction is completed, a sodium thiosulfate solution and a precious metal concentrate are obtained.

2. The method for enriching precious metals from nickel anode mud desulfurization tailings according to claim 1, characterized in that: The insulation time in step S1 is 5-20 minutes.

3. The method for enriching precious metals from nickel anode mud desulfurization tailings according to claim 1, characterized in that: The temperature of the sodium sulfite solution in step S1 is 85-95°C; and / or, the ratio of the mass of the nickel anode mud desulfurization tailings in step S1 to the volume of the added sodium sulfite solution is 1:(4-5), and the mass of the added sodium sulfite is 4-4.5 times the mass of sulfur in the nickel anode mud desulfurization tailings; and / or, the reaction time in step S1 is 10-20min, and the reaction time is kept warm for 8-15min after the reaction time ends.

4. The method for enriching precious metals from nickel anode mud desulfurization tailings according to claim 1, characterized in that: The reaction temperature of the two-stage controlled electrochlorination in step S3 is 90-100°C.

5. The method for enriching precious metals from nickel anode mud desulfurization tailings according to claim 1, characterized in that: The one-stage controlled electrochlorination and / or two-stage controlled electrochlorination reaction is a stirring reaction, and the stirring speed is 20-30 revolutions / min.

6. The method for enriching precious metals from nickel anode mud desulfurization tailings according to claim 5, characterized in that: The total reaction time of the one-stage controlled electrochlorination and the two-stage controlled electrochlorination is 8-15h.

7. The method for enriching precious metals from nickel anode mud desulfurization tailings according to any one of claims 1 to 6, characterized in that: The total mass content of gold, platinum and palladium in the precious metal concentrate is 10-15%, and the direct recovery rate of the precious metals of gold, platinum and palladium is greater than 99%.

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