Method for preparing ammonium chloroplatinate from platinum-ruthenium chloride-containing waste liquid and application of ammonium chloroplatinate

Abstract

The invention belongs to the technical field of precious metal secondary resource recycling, and discloses a method for preparing ammonium chloroplatinate from a platinum-containing ruthenium chloride waste liquid, which comprises the following steps: (1) mixing the ruthenium-containing platinum chloride waste liquid and sodium hydroxide into a mixed solution; (2) filtering and separating a platinum-containing compound clarified solution; (3) synthesizing hydrated platinum oxide; (4) filtering and separating hydrated platinum oxide; (5) synthesizing chloroplatinic acid crystals; and (6) drying the ammonium chloroplatinate crystal. Through the steps, platinum is separated from the ruthenium-containing platinum waste liquid and prepared into ammonium chloroplatinate. The invention provides a brand new method for preparing ammonium chloroplatinate from ruthenium-platinum chloride waste liquid, and by adopting the method, the environmental pollution and the production cost can be reduced, the production efficiency is improved, and meanwhile, the resource recycling is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of precious metal secondary resource recycling, in particular to a method for preparing ammonium chloroplatinate from platinum-ruthenium chloride waste liquid and its application. Background Art

[0002] Ammonium chloroplatinate, with the chemical formula (NH4)2PtCl6, is a chemical substance with egg yolk crystalline powder. Its molecular weight is 443.89, CAS number is 16919-58-7, and EINECS number is 240-973-01. The density of ammonium chloroplatinate is 3.07g / cm 3 , slightly soluble in water, insoluble in ethanol, ether and concentrated hydrochloric acid, and hygroscopic. Ammonium chloroplatinate appears as an egg-yellow crystalline powder. Ammonium chloroplatinate will completely decompose into sponge platinum when strongly heated. It is extremely insoluble in water and in ammonium chloride ice solution. Its solubility in 17.7% ammonium chloride solution is 0.003%. Its chemical properties are stable, but it will remain stable at room temperature and pressure, avoiding contact with water, moisture, oxides and acids. The applications of ammonium chloroplatinate mainly include use in various chemical analyses, as an important intermediate product in the process of purifying platinum, for platinum electroplating and the preparation of antimagnetic materials, etc. Ammonium chloroplatinate is widely used in catalytic reactions in the petrochemical, pharmaceutical and other industries, and is also used in fuel cells and electroplating technology.

[0003] At present, the preparation of metallic platinum is mainly obtained through chlorination and crystallization. However, the raw materials in this method are expensive, which increases the production cost of the enterprise. In addition, the reaction requirements of this method are strict, which is not conducive to implementation. At the same time, the utilization rate of platinum resources in this method is low, and special treatment is required later. The operation is cumbersome, which brings great inconvenience to production. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method and application of preparing ammonium chloroplatinate from platinum-ruthenium chloride waste liquid.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A method for preparing ammonium chloroplatinate from platinum-ruthenium chloride waste liquid comprises the following steps:

[0007] (1) taking a waste liquid containing platinum and ruthenium chloride, wherein the mass concentration of platinum in the waste is not less than 1%, and if it is too low, it has no recovery value, adding pure water, heating to boiling, adding a sodium hydroxide solution with a mass concentration of 30% under stirring, and continuing to stir and boil for 30 to 60 minutes, adding pure water at any time to keep the volume of the solution unchanged, removing and cooling, and obtaining a mixture solution containing a black precipitate;

[0008] (2) filtering the mixture solution containing the black precipitate with a G4 funnel to collect the filtrate, washing the filter residue with pure water, and combining the washing liquid with the filtrate to obtain a clarified solution containing the platinum compound;

[0009] (3) adding acetic acid aqueous solution dropwise to the clarified solution containing the platinum compound under stirring until the pH value of the solution is 4.5 to 5.5, thereby generating a large amount of light-colored precipitate, which is hydrated platinum oxide;

[0010] (4) filtering the hydrated platinum oxide obtained in the previous step, separating it from the mother liquor, washing the filter cake with pure water, and draining the filter cake;

[0011] (5) Take the filter cake drained in the previous step, add 36% by volume hydrochloric acid to dissolve it, then add pure water and 30% by mass concentration hydrogen peroxide, heat and boil for 4 hours, add 90-100° C. hot 45% by mass concentration ammonium chloride aqueous solution while stirring, continue stirring until a large amount of yellow ammonium chloroplatinate crystals appear;

[0012] (6) The generated yellow ammonium chloroplatinate crystals are filtered and separated from the mother liquor. The ammonium chloroplatinate crystals are washed with 95% by volume ethanol and then dried to obtain ammonium chloroplatinate.

[0013] Furthermore, in step (1), 800-1000 mL of pure water and 800 mL of a 30% mass concentration sodium hydroxide solution are added to each liter of waste liquid containing platinum and ruthenium chloride.

[0014] Furthermore, in step (2), the filter residue is washed with pure water 3 to 4 times.

[0015] Furthermore, in step (3), the mass concentration of the acetic acid aqueous solution is 50-60%.

[0016] Furthermore, in step (4), the filter cake is washed with pure water 3 to 4 times.

[0017] Furthermore, in step (5), 800-1200 mL of 36% hydrochloric acid by volume, 1000-1500 mL of pure water and 200-400 mL of 30% hydrogen peroxide by mass, and 1000-1500 g of 45% ammonium chloride aqueous solution by mass are added to every 200 g of the filter cake.

[0018] Application of the method as described above in the preparation of ammonium chloroplatinate.

[0019] The advantages and positive effects achieved by the present invention are:

[0020] 1. The present invention provides a new method for preparing ammonium chloroplatinate from ruthenium platinum chloride waste liquid. The method of the present invention can reduce environmental pollution and production costs, improve production efficiency, and achieve resource recycling.

[0021] 2. The present invention is environmentally friendly and has high process integration. It utilizes waste liquid containing ruthenium platinum chloride to prepare ammonium chloroplatinate, utilizes secondary precious metal resources, reduces production costs, reduces pollutant emissions, and realizes resource recovery and utilization.

[0022] 3. Due to the shortage of domestic and international precious metal resources in recent years, the blind mining of mineral resources in the international market has reduced mineral resources, but the demand is rising every year, causing the price of precious metals to soar. Therefore, the market for recycling waste precious metal products is relatively active. Therefore, the market application of this invention will also be quite extensive in the future. Take the supply and demand relationship of platinum from 2023 to 2024 as an example. See Table 1.

[0023]

[0024] In 2023, the platinum market is in a historic tight spot, with a shortage of up to 33 tons expected. In 2024, with the global economy shrinking, the gap is expected to be 11 tons. The demand figures from 2023 to 2024 also show the importance of platinum recycling. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the embodiments. The following embodiments are descriptive rather than restrictive, and the protection scope of the present invention cannot be limited by the following embodiments.

[0026] The various experimental operations involved in the specific embodiments are all routine techniques in the art. For parts not specially annotated in this document, ordinary technicians in the art can implement them by referring to various commonly used reference books, scientific and technological literature or related instructions, manuals, etc. before the filing date of this invention.

[0027] A method for preparing ammonium chloroplatinate from platinum-ruthenium chloride waste liquid comprises the following steps:

[0028] (1) taking a waste liquid containing platinum and ruthenium chloride, wherein the mass concentration of platinum in the waste is not less than 1%, and if it is too low, it has no recovery value, adding pure water, heating to boiling, adding a sodium hydroxide solution with a mass concentration of 30% under stirring, and continuing to stir and boil for 30 to 60 minutes, adding pure water at any time to keep the volume of the solution unchanged, removing and cooling, and obtaining a mixture solution containing a black precipitate;

[0029] (2) filtering the mixture solution containing the black precipitate with a G4 funnel to collect the filtrate, washing the filter residue with pure water, and combining the washing liquid with the filtrate to obtain a clarified solution containing the platinum compound;

[0030] (3) adding acetic acid aqueous solution dropwise to the clarified solution containing the platinum compound under stirring until the pH value of the solution is 4.5 to 5.5, thereby generating a large amount of light-colored precipitate, which is hydrated platinum oxide;

[0031] (4) filtering the hydrated platinum oxide obtained in the previous step, separating it from the mother liquor, washing the filter cake with pure water, and draining the filter cake;

[0032] (5) Take the filter cake drained in the previous step, add 36% by volume hydrochloric acid to dissolve it, then add pure water and 30% by mass concentration hydrogen peroxide, heat and boil for 4 hours, add 90-100° C. hot 45% by mass concentration ammonium chloride aqueous solution while stirring, continue stirring until a large amount of yellow ammonium chloroplatinate crystals appear;

[0033] (6) The generated yellow ammonium chloroplatinate crystals are filtered and separated from the mother liquor. The ammonium chloroplatinate crystals are washed with 95% by volume ethanol and then dried to obtain ammonium chloroplatinate.

[0034] Preferably, in step (1), 800-1000 mL of pure water and 800 mL of 30% mass concentration sodium hydroxide solution are added to each liter of waste liquid containing platinum and ruthenium chloride.

[0035] Preferably, in step (2), the filter residue is washed with pure water 3 to 4 times.

[0036] Preferably, in step (3), the mass concentration of the acetic acid aqueous solution is 50-60%.

[0037] Preferably, in step (4), the filter cake is washed with pure water 3 to 4 times.

[0038] Preferably, in step (5), 800-1200 mL of 36% hydrochloric acid by volume, 1000-1500 mL of pure water and 200-400 mL of 30% hydrogen peroxide by mass, and 1000-1500 g of 45% ammonium chloride aqueous solution are added to every 200 g of filter cake.

[0039] Application of the method as described above in the preparation of ammonium chloroplatinate.

[0040] Specifically, the relevant preparation and detection are as follows:

[0041] Example 1

[0042] A method for preparing ammonium chloroplatinate from platinum-ruthenium chloride waste liquid, characterized in that it comprises the following steps:

[0043] (1) taking 500 ml of waste liquid containing platinum and ruthenium chloride, adding pure water to a total volume of 1000 ml, heating to a boiling state, adding 800 ml of a 30% sodium hydroxide solution under stirring, continuing to stir and boil for 60 minutes, replenishing pure water at any time to keep the solution volume unchanged, removing and cooling, and obtaining a mixture solution containing a black precipitate;

[0044] The platinum ruthenium chloride waste liquid is produced in the process of producing aerospace industry catalysts. In the past, the waste liquid was treated as waste liquid and not recycled because the waste liquid content was too low. In recent years, due to the instability of precious metal market resources and prices, the user has adjusted the waste liquid production process and recycled the waste liquid. The relevant indicators in the waste liquid before and after the improvement are shown in Table 2.

[0045] Table 2 Related indicators of new and old processes for ruthenium platinum chloride wastewater

[0046]

[0047] The above percentages represent mass percentages.

[0048] (2) filtering the mixed solution in the previous step to collect the filtrate, washing the filter residue with pure water for 4 times, and combining the washing liquid with the filtrate to obtain a clarified solution containing the platinum compound;

[0049] (3) adding a 50% acetic acid aqueous solution to the clarified solution containing the platinum compound in the previous step under stirring until the pH value of the solution is 4.5, thereby generating a large amount of light-colored precipitate, which is hydrated platinum oxide;

[0050] (4) The hydrated platinum oxide obtained in the previous step is filtered and separated from the mother liquor, and the filter cake is washed with pure water for 3 to 4 times and then dried.

[0051] (5) Take 200 g of the filter cake drained in the previous step, add 800 mL of 36% hydrochloric acid by volume to dissolve, then add 1000 mL of pure water and 200 mL of 30% hydrogen peroxide solution by mass, heat and boil for 20 minutes, then add 1000 g of 45% ammonium chloride aqueous solution at 90° C. while stirring, continue stirring for 10 minutes, until a large amount of yellow ammonium chloroplatinate crystals appear;

[0052] (6) The generated ammonium chloroplatinate crystals are filtered and separated from the mother liquor, and the ammonium chloroplatinate crystals are washed with 95% ethanol for 4 times and then dried at 90° C. to obtain a finished product.

[0053] Using the same method, for the same batch of platinum ruthenium chloride waste liquid, a 50% acetic acid aqueous solution was added dropwise to the clarified liquid containing the platinum compound in step (3) in Example 1 under stirring, and the pH was adjusted to 3.7 (i.e., Example 2) and 5.8 (i.e., Example 3) to perform tests with the same other conditions.

[0054] The comparison table of test results is shown in Table 3.

[0055] Table 3

[0056] Example Quantity of Platinum Ruthenium Chloride Wastewater Platinum content of original waste liquid % 50% acetic acid to pH Ammonium chloroplatinate quantity G 1 500ML 17.6 4.5 8 2 500ML 17.6 3.7 - 3 500ML 17.6 5.8 -

[0057] It can be determined from Table 3 that when the pH value is adjusted to 4.5, it is the best solution for recovering ammonium chloroplatinate from waste liquid.

[0058] Using the same method, the same batch of platinum ruthenium chloride waste liquid was subjected to the same test under the same conditions except that the 30% sodium hydroxide solution by mass in step (1) of Example 1 was replaced by a 20% sodium hydroxide solution by mass (ie, Example 4).

[0059] The comparison table of test results is shown in Table 4.

[0060] Table 4

[0061] Example Quantity of Platinum Ruthenium Chloride Wastewater Platinum content of original waste liquid % Sodium hydroxide mass concentration% Ammonium chloroplatinate quantity G 1 500ML 17.6 30 8 4 500ML 17.6 20 2.4

[0062] Table 4 shows that adding sodium hydroxide at a mass concentration of 30% is the best solution for recovering ammonium chloroplatinate from waste liquid.

[0063] At the same time, by comparing Examples 1 to 4, it can be seen that in the method of the present invention, the clarified solution containing the platinum compound in step (3) is added dropwise with stirring an aqueous solution of acetic acid having a mass concentration of 50%, and the pH is adjusted to 4.5. There is a synergistic effect between the clarified solution and the sodium hydroxide solution having a mass concentration of 30% in step (1), and the two can significantly synergistically improve the relevant properties of the prepared ammonium chloroplatinate.

[0064] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for preparing ammonium chloroplatinate from waste liquid containing platinum and ruthenium chloride, characterized in that: The steps include: (1) taking a waste liquid containing platinum and ruthenium chloride, wherein the mass concentration of platinum in the waste is not less than 1%, adding pure water, heating to boiling, adding a sodium hydroxide solution having a mass concentration of 30% under stirring, continuing stirring and boiling for 30 to 60 minutes, replenishing pure water at any time to keep the volume of the solution unchanged, removing and cooling, and obtaining a mixture solution containing a black precipitate; (2) filtering the mixture solution containing the black precipitate with a G4 funnel to collect the filtrate, washing the filter residue with pure water, and combining the washing liquid with the filtrate to obtain a clarified solution containing the platinum compound; (3) adding an acetic acid aqueous solution dropwise to the clarified solution containing the platinum compound under stirring until the pH value of the solution is 4.5 to 5.5, thereby generating a light-colored precipitate, which is hydrated platinum oxide; (4) filtering the hydrated platinum oxide obtained in the previous step, separating it from the mother liquor, washing the filter cake with pure water, and draining the filter cake; (5) Take the filter cake drained in the previous step, add 36% by volume hydrochloric acid to dissolve it, then add pure water and 30% by mass concentration hydrogen peroxide, heat and boil for 4 hours, add 90-100° C. hot 45% by mass concentration ammonium chloride aqueous solution while stirring, continue stirring until a large amount of yellow ammonium chloroplatinate crystals appear; (6) The generated yellow ammonium chloroplatinate crystals are filtered and separated from the mother liquor. The ammonium chloroplatinate crystals are washed with 95% by volume ethanol and then dried to obtain ammonium chloroplatinate.

2. The method according to claim 1, characterized in that: In step (1), 800-1000 mL of pure water and 800 mL of a 30% mass concentration sodium hydroxide solution are added to each liter of waste liquid containing platinum and ruthenium chloride.

3. The method according to claim 1, characterized in that: In step (2), the filter residue is washed with pure water 3 to 4 times.

4. The method according to claim 1, characterized in that: In step (3), the mass concentration of the acetic acid aqueous solution is 50-60%.

5. The method according to claim 1, characterized in that: In step (4), the filter cake is washed with pure water 3 to 4 times.

6. The method according to any one of claims 1 to 5, characterized in that: In step (5), 800-1200 mL of 36% hydrochloric acid by volume, 1000-1500 mL of pure water and 200-400 mL of 30% hydrogen peroxide by mass concentration, and 1000-1500 g of 45% ammonium chloride aqueous solution by mass concentration are added to every 200 g of the filter cake.

7. Use of the method according to any one of claims 1 to 6 in the preparation of ammonium chloroplatinate.

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