A method for recovering platinum from ammonium chloride precipitation mother liquor
By introducing prereaction, efficient enrichment, precipitation recovery and refining treatment in the traditional aqueous regia dissolving-ammonium chloride precipitation method, the problem of low platinum yield in traditional processes is solved, and efficient recovery of more than 99.9% of platinum is achieved, which is suitable for industrial applications.
Patent Information
- Application Number
- CN202411659805.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-04-04
AI Technical Summary
During the traditional water regia dissolving-ammonium chloride precipitation method, the direct yield of platinum is not high, which seriously restricts production.
The method of recovering platinum from the precipitation mother liquor of ammonium chloride is adopted, including four main processes: prereaction, efficient enrichment, precipitation recovery and refining treatment. The specific steps include: concentrating the precipitation mother liquor of ammonium chloride, adding an oxidant and tin dichloride for pre-reaction; efficient enrichment using ethyl acetate; precipitation recovery through hydrazine hydrate; and finally refining repeatedly through water regia dissolving-ammonium chloride precipitation method to obtain sponge platinum product.
The efficient recovery of platinum in the precipitated mother liquor of ammonium chloride is achieved, and the recovery rate of platinum can reach more than 99.9%, which improves the yield of the platinum refining process and simplifies the process flow, which is suitable for industrial production.
Smart Images
Figure CN119753339A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of wet process of precious metal metallurgy technology, and in particular relates to a method for recovering platinum from ammonium chloride precipitation mother liquor. Background Art
[0002] Among the platinum group metals, the most studied is the refining technology of platinum. There are many methods to produce high-purity platinum with a purity of more than 99.9%. These methods can be summarized as repeated precipitation with ammonium chloride, carrier hydrolysis, carrier hydrolysis-ion exchange, bromate hydrolysis, chlorination carbonyl method, molten salt electrolysis, regional smelting, etc. However, the more mature process for industrial application is the traditional aqua regia dissolution-ammonium chloride precipitation repeated refining method. This method dissolves high-platinum materials such as crude platinum ammonium salt in aqua regia, drives away nitrate, and connects ammonium chloride precipitation to repeatedly refine ammonium chloroplatinate, which is calcined, decomposed or reduced to produce sponge platinum products that meet national standards. The outstanding advantage of this method is that it has strong adaptability to raw materials and can stably produce 99.99% sponge platinum products. However, the technology has many repeated refining times, resulting in a low direct recovery rate of platinum in the production process, which seriously restricts production. Summary of the invention
[0003] In view of the problems existing in the prior art, the present invention provides a method for recovering platinum from ammonium chloride precipitation mother liquor. The ammonium chloride precipitation mother liquor refers to the ammonium chloride precipitation mother liquor produced in the process of repeatedly refining platinum by the traditional aqua regia dissolution-ammonium chloride precipitation method. The process route of the method includes four main processes of "pre-reaction-efficient enrichment-precipitation recovery-refining treatment", which can realize the efficient recovery of platinum in the ammonium chloride precipitation mother liquor.
[0004] The present invention specifically includes the following contents:
[0005] A method for recovering platinum from ammonium chloride precipitation mother liquor comprises the following steps:
[0006] S1, pre-reaction: concentrating the ammonium chloride precipitation mother liquor, then adding an oxidant accounting for 1-2% of the volume of the concentrated ammonium chloride precipitation mother liquor, wherein the oxidant is a hydrogen peroxide solution with a mass concentration of 25-35% and / or a sodium chlorate solution with a mass concentration of 30-40%, stirring for reaction; then adding tin dichloride to the reaction system at a ratio of 10-30 g / L, heating the reaction system to continuously boil, and obtaining a pre-reaction treatment solution;
[0007] S2, efficient enrichment: adding ethyl acetate accounting for 50-100% of the volume of the pre-reaction treatment liquid, stirring and reacting at 40-65° C., and then standing and stratifying to obtain an upper layer liquid; adding a dilute hydrochloric acid solution to the upper layer liquid, stirring and reacting, and standing and stratifying to obtain an ethyl acetate loading liquid;
[0008] S3, precipitation recovery: adding hydrazine hydrate solution to the ethyl acetate loading liquid until the pH of the solution system is 8-10, and then boiling the solution system for reaction for 1.5-3 hours to obtain platinum-containing precipitation recovery material.
[0009] Furthermore, it also includes S4 refining treatment: the platinum-containing precipitate recovery material is repeatedly refined by aqua regia dissolution-ammonium chloride precipitation method to finally obtain a sponge platinum product that meets national standards.
[0010] Further, in step S1, the ammonium chloride precipitation mother liquor is concentrated to 25-30% of the original volume.
[0011] Furthermore, the stirring reaction time in step S1 is 1-1.5 hours; and / or, the continuous boiling time of the reaction system in step S1 is 2-3 hours.
[0012] Further, in step S2, ethyl acetate is added and stirred for reaction for 10-15 minutes, and the mixture is allowed to stand for 2-3 hours after the reaction; and / or, dilute hydrochloric acid is added and stirred for reaction at room temperature for 10-15 minutes, and the mixture is allowed to stand for 2-3 hours after the reaction.
[0013] Furthermore, the concentration of the dilute hydrochloric acid in step S2 is 0.4-0.8 mol / L; and / or the amount of the dilute hydrochloric acid solution added accounts for 10-20% of the total volume of the upper liquid.
[0014] Furthermore, the mass concentration of the hydrazine hydrate solution in step S3 is 12-18%.
[0015] Furthermore, the mass of platinum in the platinum-containing precipitation recovery material accounts for more than 99.9% of the total amount of platinum in the ammonium chloride precipitation mother liquor.
[0016] Beneficial effects of the present invention:
[0017] (1) The method for recovering platinum from ammonium chloride precipitation mother liquor disclosed in the present invention comprises the following steps: firstly, the ammonium chloride precipitation mother liquor is concentrated. By concentrating, the volume of the mother liquor can be reduced, the concentration of the reactants in the subsequent treatment can be increased, and thus the reaction efficiency and the purity of the product can be improved. Then, an oxidant accounting for 1-2% of the volume of the concentrated ammonium chloride precipitation mother liquor is added, and the oxidant is a hydrogen peroxide solution with a mass concentration of 25-35% and / or a sodium chlorate solution with a mass concentration of 30-40%, and the reaction is stirred. This step can promote the conversion of chloroplatinic acid, subchloroplatinic acid and ammonium subchloroplatinate into ammonium chloroplatinate for recovery; then, tin dichloride is added to the reaction system at a ratio of 10-30 g / L, and the reaction system is heated to continuously boil to obtain a pre-reaction treatment liquid. In this step, the addition of tin dichloride can reduce and change the valence state of platinum, and convert it into a system that is more easily extracted by ethyl acetate, thereby realizing the extraction and enrichment of platinum by ethyl acetate by utilizing the solubility difference. Through the two-step pre-reaction, impurities in the mother liquor can be removed, the purity of platinum can be increased, and platinum can be converted into a valence state that is easy to extract and recover. The method disclosed by the invention comprises adding ethyl acetate accounting for 50-100% of the volume of the pre-reaction treatment liquid, stirring at 40-65°C for extraction, and obtaining an upper layer liquid containing platinum; adding a dilute hydrochloric acid solution to the upper layer liquid, stirring for reaction, standing for stratification, and obtaining an ethyl acetate loading liquid; and further enriching and purifying the platinum through extraction and acid addition.
[0018] (2) The method for recovering platinum from ammonium chloride precipitation mother liquor disclosed in the present invention breaks through the original process limitations by designing the process flow and limiting the reaction parameters of each step. The process flow is simple, economical, environmentally friendly, convenient and effective, and easy to realize industrial production. The method can stably and efficiently recover platinum from ammonium chloride precipitation mother liquor, thereby improving the yield of the platinum refining process. The recovery rate of platinum can reach more than 99.9%. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 The present invention is a schematic diagram of the process flow of the method disclosed in the present invention. DETAILED DESCRIPTION
[0020] 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.
[0021] Reference Figure 1 , a method for recovering platinum from ammonium chloride precipitation mother liquor, comprising the following steps:
[0022] S1, pre-reaction: the ammonium chloride precipitation mother liquor is concentrated to 25-30% of the original volume, and then an oxidant is added accounting for 1-2% of the volume of the concentrated ammonium chloride precipitation mother liquor, wherein the oxidant is a hydrogen peroxide solution with a mass concentration of 25-35% and / or a sodium chlorate solution with a mass concentration of 30-40%, and the reaction is stirred for 1-1.5h; then tin dichloride is added to the reaction system at a ratio of 10-30g / L, and the reaction system is heated to continue boiling for 2-3h to obtain a pre-reaction treatment liquid;
[0023] S2, efficient enrichment: add ethyl acetate accounting for 50-100% of the volume of the pre-reaction treatment liquid, stir and react at 40-65°C for 10-15 minutes, and then stand and separate for 2-3 hours to obtain an upper layer liquid; add a dilute hydrochloric acid solution with a concentration of 0.4-0.8 mol / L to the upper layer liquid, the amount of the dilute hydrochloric acid solution added accounts for 10-20% of the total volume of the upper layer liquid, stir and react for 10-15 minutes, and stand and separate for 2-3 hours to obtain an ethyl acetate load liquid;
[0024] S3, precipitation recovery: adding a hydrazine hydrate solution with a mass concentration of 12-18% to the ethyl acetate load liquid until the solution system has a pH of 8-10, and then boiling the solution system for a reaction of 1.5-3 hours to obtain a platinum-containing precipitation recovery material, wherein the mass of platinum in the platinum-containing precipitation recovery material accounts for more than 99.9% of the total amount of platinum in the ammonium chloride precipitation mother liquor;
[0025] S4, refining treatment: the platinum-containing precipitate recovery material is repeatedly refined by an aqua regia dissolution-ammonium chloride precipitation method to finally obtain a sponge platinum product that meets national standards.
[0026] Example 1
[0027] A method for recovering platinum from ammonium chloride precipitation mother liquor comprises the following steps:
[0028] S1, pre-reaction: 1500L of ammonium chloride precipitation mother liquor produced in the platinum refining process was concentrated to 450L, and then 7L of 35% sodium chlorate was added, and the mixture was slowly and evenly stirred for 1h to obtain a total of 430L of pre-reaction treatment liquid 1. 8kg of tin dichloride was added to the pre-reaction treatment liquid 1, and the mixture was slowly and evenly heated to boiling, and the reaction was continued for 3h under boiling conditions to obtain a total of 420L of pre-reaction treatment liquid 2.
[0029] S2, efficient enrichment: add 400 L of ethyl acetate to the 455 L pre-reaction treatment solution 2 obtained in step (1), stir and react for 15 min at a constant temperature of 55° C., let stand for 2 h, slowly discharge the bottom solution to obtain an upper ethyl acetate loading solution 1 of 400 L. Continue to add 40 L of 0.5 mol / L dilute hydrochloric acid solution to the ethyl acetate loading solution 1, stir and react for 10 min at room temperature, let stand for 2 h, slowly separate and discharge the bottom solution to obtain an ethyl acetate loading solution 2 of 390 L.
[0030] S3, precipitation recovery: dilute 85% of hydrazine hydrate to 15% with pure water, and slowly and evenly add it to the ethyl acetate loaded solution 2 obtained in step (2), react until the solution system pH = 9, continue boiling reaction for 2h, separate the solid and liquid, wash the filter cake with pure water until it is neutral, and obtain 19.38kg of platinum-containing precipitation recovery material, with a platinum recovery rate of 99.93%.
[0031] S4, refining treatment: The platinum-containing precipitate recovered material obtained in step 3 is further refined repeatedly through the traditional aqua regia dissolution-ammonium chloride precipitation method to obtain a total of 0.721 kg of sponge platinum products that meet national standards, thereby achieving efficient recovery of platinum in the ammonium chloride precipitation mother liquor.
[0032] Example 2
[0033] S1, pre-reaction: 2000L of ammonium chloride precipitation mother liquor produced in the platinum refining process was concentrated to 500L, and then 5L of 30% hydrogen peroxide was added, and the mixture was slowly and evenly stirred for 1h to obtain a total of 480L of pre-reaction treatment liquid 1. A total volume of 7.5kg of tin dichloride was added to the pre-reaction treatment liquid 1, and the mixture was slowly and evenly heated to boiling, and the reaction was continued for 2h under boiling conditions to obtain a total of 455L of pre-reaction treatment liquid 2.
[0034] S2, efficient enrichment: add 270L of ethyl acetate to the 455L pre-reaction treatment solution 2 obtained in step (1), stir and react for 12min at a constant temperature of 45°C, let stand for 2h, slowly discharge the bottom solution to obtain the upper ethyl acetate loading solution 1 of 455L. Continue to add 70L of 0.5mol / L dilute hydrochloric acid solution to the ethyl acetate loading solution 1, stir and react for 10min at room temperature, let stand for 2h, slowly separate and discharge the bottom solution to obtain the ethyl acetate loading solution 2 of 435L.
[0035] S3, precipitation recovery: dilute 85% of hydrazine hydrate to 15% with pure water, and slowly and evenly add it to the ethyl acetate loaded solution 2 obtained in step (2), react until the solution system pH = 9, continue boiling reaction for 2h, separate the solid and liquid, wash the filter cake with pure water until it is neutral, and obtain 25.2kg of platinum-containing precipitation recovery material, with a platinum recovery rate of 99.98%.
[0036] S4, refining treatment: The platinum-containing precipitate recovered material obtained in step 3 is further refined repeatedly through the traditional aqua regia dissolution-ammonium chloride precipitation method to obtain a total of 0.985 kg of sponge platinum products that meet national standards, thereby achieving efficient recovery of platinum in the ammonium chloride precipitation mother liquor.
[0037] Example 3
[0038] S1, pre-reaction: 1000L of ammonium chloride precipitation mother liquor produced in the platinum refining process was concentrated to 300L, and then 2L of 35% sodium chlorate and 2L of 30% hydrogen peroxide were added, and the mixture was slowly and evenly stirred for 1h to obtain a total of 295L of pre-reaction treatment liquid 1. 3kg of tin dichloride was added to the pre-reaction treatment liquid 1, and the mixture was slowly and evenly heated to boiling, and the reaction was continued for 2.5h under boiling conditions to obtain a total of 295L of pre-reaction treatment liquid 2.
[0039] S2, efficient enrichment: add 200 L of ethyl acetate to the 455 L pre-reaction treatment solution 2 obtained in step (1), stir and react for 10 min at a constant temperature of 50° C., let stand for 2 h, slowly discharge the bottom solution to obtain an upper ethyl acetate loading solution 1 totaling 200 L. Continue to add 30 L of 0.5 mol / L dilute hydrochloric acid solution to the ethyl acetate loading solution 1, stir and react for 10 min at room temperature, let stand for 2 h, slowly separate and discharge the bottom solution to obtain an ethyl acetate loading solution 2 totaling 200 L.
[0040] S3, precipitation recovery: dilute 85% of hydrazine hydrate to 15% with pure water, and slowly and evenly add it to the ethyl acetate loaded solution 2 obtained in step (2), react until the solution system pH = 9, continue boiling reaction for 2h, separate the solid and liquid, wash the filter cake with pure water until it is neutral, and obtain 13.67kg of platinum-containing precipitation recovery material, with a platinum recovery rate of 99.95%.
[0041] S4, refining treatment: The platinum-containing precipitate recovered material obtained in step 3 is further refined repeatedly through the traditional aqua regia dissolution-ammonium chloride precipitation method to obtain a total of 0.519 kg of sponge platinum products that meet national standards, thereby achieving efficient recovery of platinum in the ammonium chloride precipitation mother liquor.
[0042] Example 4
[0043] A method for recovering platinum from ammonium chloride precipitation mother liquor comprises the following steps:
[0044] S1, pre-reaction: the ammonium chloride precipitation mother liquor is concentrated to 25% of the original volume, and then an oxidant accounting for 1% of the volume of the concentrated ammonium chloride precipitation mother liquor is added, wherein the oxidant is a sodium chlorate solution with a mass concentration of 30%, and the reaction is stirred for 1 hour; then tin dichloride is added to the reaction system at a ratio of 10g / L, and the reaction system is heated to continue boiling for 2 hours to obtain a pre-reaction treatment liquid;
[0045] S2, efficient enrichment: adding ethyl acetate accounting for 50% of the volume of the pre-reaction treatment liquid, stirring and reacting at 40°C for 10 minutes, and then standing and stratifying for 2 hours to obtain an upper layer liquid; adding a dilute hydrochloric acid solution with a concentration of 0.4 mol / L to the upper layer liquid, the amount of the dilute hydrochloric acid solution added accounting for 10% of the total volume of the upper layer liquid, stirring and reacting for 10 minutes, and standing and stratifying for 2 hours to obtain an ethyl acetate load liquid;
[0046] S3, precipitation recovery: adding a hydrazine hydrate solution with a mass concentration of 12% to the ethyl acetate load liquid until the solution system has a pH of 8-9, and then boiling the solution system for reaction for 1.5 hours to obtain a platinum-containing precipitation recovery material, wherein the mass of platinum in the platinum-containing precipitation recovery material accounts for 99.91% of the total amount of platinum in the ammonium chloride precipitation mother liquor;
[0047] S4, refining treatment: the platinum-containing precipitate recovery material is repeatedly refined by an aqua regia dissolution-ammonium chloride precipitation method to finally obtain a sponge platinum product that meets national standards.
[0048] Example 5
[0049] A method for recovering platinum from ammonium chloride precipitation mother liquor comprises the following steps:
[0050] S1, pre-reaction: the ammonium chloride precipitation mother liquor is concentrated to 30% of the original volume, and then an oxidant accounting for 2% of the volume of the concentrated ammonium chloride precipitation mother liquor is added, wherein the oxidant is a hydrogen peroxide solution with a mass concentration of 35% and a sodium chlorate solution with a mass concentration of 40%, and the reaction is stirred for 1.5 hours; then tin dichloride is added to the reaction system at a ratio of 30g / L, and the reaction system is heated to continue boiling for 3 hours to obtain a pre-reaction treatment liquid;
[0051] S2, efficient enrichment: add ethyl acetate accounting for 100% of the volume of the pre-reaction treatment liquid, stir and react at 65°C for 15 minutes, then stand for 3 hours to separate layers, and obtain an upper layer liquid; add a dilute hydrochloric acid solution with a concentration of 0.8 mol / L to the upper layer liquid, the amount of the dilute hydrochloric acid solution added accounts for 20% of the total volume of the upper layer liquid, stir and react for 15 minutes, stand for 3 hours to separate layers, and obtain an ethyl acetate load liquid;
[0052] S3, precipitation recovery: adding a hydrazine hydrate solution with a mass concentration of 18% to the ethyl acetate load liquid until the pH of the solution system is 9.5-10, and then boiling the solution system for reaction for 3 hours to obtain a platinum-containing precipitation recovery material, wherein the mass of platinum in the platinum-containing precipitation recovery material accounts for 99.98% of the total amount of platinum in the ammonium chloride precipitation mother liquor;
[0053] S4, refining treatment: the platinum-containing precipitate recovery material is repeatedly refined by an aqua regia dissolution-ammonium chloride precipitation method to finally obtain a sponge platinum product that meets national standards.
[0054] Example 6
[0055] A method for recovering platinum from ammonium chloride precipitation mother liquor comprises the following steps:
[0056] S1, pre-reaction: the ammonium chloride precipitation mother liquor is concentrated to 30% of the original volume, and then an oxidant accounting for 2% of the volume of the concentrated ammonium chloride precipitation mother liquor is added, wherein the oxidant is a hydrogen peroxide solution with a mass concentration of 30%, and the reaction is stirred for 1 hour; then tin dichloride is added to the reaction system at a ratio of 20g / L, and the reaction system is heated to continue boiling for 2.5 hours to obtain a pre-reaction treatment liquid;
[0057] S2, efficient enrichment: adding ethyl acetate accounting for 80% of the volume of the pre-reaction treatment liquid, stirring and reacting at 60°C for 12 minutes, and then standing for 2 hours to separate layers to obtain an upper layer liquid; adding a dilute hydrochloric acid solution with a concentration of 0.6 mol / L to the upper layer liquid, wherein the amount of the dilute hydrochloric acid solution added accounts for 15% of the total volume of the upper layer liquid, stirring and reacting for 12 minutes, and standing for 2 hours to separate layers to obtain an ethyl acetate loading liquid;
[0058] S3, precipitation recovery: adding a hydrazine hydrate solution with a mass concentration of 15% to the ethyl acetate load liquid until the solution system has a pH of 8.8-9.2, and then boiling the solution system for reaction for 2 hours to obtain a platinum-containing precipitation recovery material, wherein the mass of platinum in the platinum-containing precipitation recovery material accounts for 99.99% of the total amount of platinum in the ammonium chloride precipitation mother liquor;
[0059] S4, refining treatment: the platinum-containing precipitate recovery material is repeatedly refined by an aqua regia dissolution-ammonium chloride precipitation method to finally obtain a sponge platinum product that meets national standards.
[0060] Comparative Example 1
[0061] The difference between this comparative example and Example 6 is that the amount of the oxidant added in step S1 is 3% of the volume of the concentrated ammonium chloride precipitation mother liquor, and other conditions are the same. The recovery rate of platinum in this comparative example is 99.1%.
[0062] Comparative Example 2
[0063] The difference between this comparative example and Example 6 is that the oxidant added in step S1 is hydrogen peroxide with a concentration of 20%, and other conditions are the same. The recovery rate of platinum in this comparative example is 98.3%.
[0064] Comparative Example 3
[0065] The difference between this comparative example and Example 6 is that the oxidant added in step S1 is hydrogen peroxide with a concentration of 40%, and other conditions are the same. The recovery rate of platinum in this comparative example is 99.7%.
[0066] Comparative Example 4
[0067] The difference between this comparative example and Example 6 is that the addition ratio of tin dichloride in step S1 is 8 g / L, and other conditions are the same. The recovery rate of platinum in this comparative example is 96.5%.
[0068] Comparative Example 5
[0069] The difference between this comparative example and Example 6 is that the addition ratio of tin dichloride in step S1 is 35 g / L, and other conditions are the same. The recovery rate of platinum in this comparative example is 99.6%.
[0070] Comparative Example 6
[0071] The difference between this comparative example and Example 6 is that the amount of ethyl acetate added in step S2 accounts for 40% of the volume of the pre-reaction treatment liquid, and other conditions are the same. The recovery rate of platinum in this comparative example is 94.3%.
[0072] Comparative Example 6
[0073] The difference between this comparative example and Example 6 is that the amount of ethyl acetate added in step S2 accounts for 200% of the volume of the pre-reaction treatment liquid, and other conditions are the same. The recovery rate of platinum in this comparative example is 99.95%.
[0074] Comparative Example 7
[0075] The difference between this comparative example and Example 6 is that the temperature of stirring the reaction after adding ethyl acetate in step S2 is 30° C., and other conditions are the same. The recovery rate of platinum in this comparative example is 97.6%.
[0076] Comparative Example 8
[0077] The difference between this comparative example and Example 6 is that the temperature of stirring the reaction after adding ethyl acetate in step S2 is 70° C., and other conditions are the same. The recovery rate of platinum in this comparative example is 99.7%.
[0078] 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 recovering platinum from ammonium chloride precipitation mother liquor, characterized in that: The following steps are involved: S1, pre-reaction: concentrating the ammonium chloride precipitation mother liquor, then adding an oxidant accounting for 1-2% of the volume of the concentrated ammonium chloride precipitation mother liquor, wherein the oxidant is a hydrogen peroxide solution with a mass concentration of 25-35% and / or a sodium chlorate solution with a mass concentration of 30-40%, stirring for reaction; then adding tin dichloride to the reaction system at a ratio of 10-30 g / L, heating the reaction system to continuously boil, and obtaining a pre-reaction treatment solution; S2, efficient enrichment: adding ethyl acetate accounting for 50-100% of the volume of the pre-reaction treatment liquid, stirring and reacting at 40-65° C., and then standing and stratifying to obtain an upper layer liquid; adding a dilute hydrochloric acid solution to the upper layer liquid, stirring and reacting, and standing and stratifying to obtain an ethyl acetate loading liquid; S3, precipitation recovery: adding hydrazine hydrate solution to the ethyl acetate loading liquid until the pH of the solution system is 8-10, and then boiling the solution system for reaction for 1.5-3 hours to obtain platinum-containing precipitation recovery material.
2. A method for recovering platinum from an ammonium chloride precipitation mother liquor according to claim 1, characterized in that: The method also includes S4 refining treatment: the platinum-containing precipitate recovery material is repeatedly refined by an aqua regia dissolution-ammonium chloride precipitation method to finally obtain a sponge platinum product.
3. A method for recovering platinum from an ammonium chloride precipitation mother liquor according to claim 1, characterized in that: Step S1: Concentrate the ammonium chloride precipitation mother liquor to 25-30% of the original volume.
4. A method for recovering platinum from an ammonium chloride precipitation mother liquor according to claim 1, characterized in that: The stirring reaction time in step S1 is 1-1.5 hours; and / or, the continuous boiling time of the reaction system in step S1 is 2-3 hours.
5. A method for recovering platinum from an ammonium chloride precipitation mother liquor according to claim 1, characterized in that: In step S2, ethyl acetate is added and stirred for reaction for 10-15 minutes, and the mixture is allowed to stand for 2-3 hours after the reaction; and / or, dilute hydrochloric acid is added and stirred for reaction at room temperature for 10-15 minutes, and the mixture is allowed to stand for 2-3 hours after the reaction.
6. A method for recovering platinum from an ammonium chloride precipitation mother liquor according to claim 1, characterized in that: The concentration of the dilute hydrochloric acid in step S2 is 0.4-0.8 mol / L; and / or the amount of the dilute hydrochloric acid solution added accounts for 10-20% of the total volume of the upper liquid.
7. A method for recovering platinum from ammonium chloride precipitation mother liquor according to claim 1, characterized in that: The mass concentration of the hydrazine hydrate solution in step S3 is 12-18%.
8. The method for recovering platinum from an ammonium chloride precipitation mother liquor according to any one of claims 1 to 7, characterized in that: The mass of platinum in the platinum-containing precipitation recovery material accounts for more than 99.9% of the total amount of platinum in the ammonium chloride precipitation mother liquor.