Preparation method and application of high-purity platinum

Abstract

The invention belongs to the technical field of nonferrous metallurgy, and particularly relates to a preparation method and application of high-purity platinum. According to the preparation method of the high-purity platinum, the high-purity platinum is prepared through the steps of direct chlorination treatment, boiling and filtering treatment, cation exchange resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, hot water washing, acid washing and the like, a large amount of ammonia-nitrogen wastewater is not generated, and the equipment cost is low; meanwhile, the purity and the yield of the high-purity platinum are improved by optimizing a sulfur dioxide treatment process and hydrazine hydrate treatment, so that the technical problem that a preparation method of the high-purity platinum is lacked in the prior art is solved.

Description

Technical Field

[0001] The present application belongs to the technical field of nonferrous metal metallurgy, and in particular relates to a preparation method and application of high-purity platinum. Background Art

[0002] Platinum has good chemical stability, high electrical and thermal conductivity, and its unique electromagnetic and optical properties are very important in electrical instruments, precision alloys, chemical industry and pharmaceutical industry. Different fields have different requirements for the purity of platinum. When platinum is used as a catalyst material, the purity requirement is relatively low. However, with the development of electronic materials, related process technologies are constantly improving and upgrading, and the requirements for platinum purity are becoming higher and higher. For example, in the optical field, the purity of vapor-deposited thin film materials and in the semiconductor field, the purity of sputtering targets are required to be above 5N, that is, the purity of platinum raw materials is required to be ≥99.999%.

[0003] Currently, there are not many methods for preparing high-purity platinum. The main method in China is repeated precipitation of ammonium chloroplatinate. The repeated precipitation of ammonium chloroplatinate is costly and labor-intensive to produce high-purity platinum, and also produces a large amount of ammonia nitrogen-containing wastewater. With the improvement of environmental protection requirements, the cost of wastewater treatment will gradually increase, which limits the large-scale industrial production of high-purity platinum by repeated precipitation of ammonium chloroplatinate. Foreign countries also use the physical method of regional smelting to prepare high-purity platinum. This method has extremely high requirements for equipment and high smelting losses. It is costly when the amount is small, so it is difficult to be widely used in actual industrial production. Therefore, the current method of producing high-purity platinum is not suitable for industrial production. Summary of the invention

[0004] In view of this, the present application provides a preparation method and application of high-purity platinum, which are used to solve the technical problem of lack of preparation method of high-purity platinum in the prior art.

[0005] The first aspect of the present application provides a method for preparing high-purity platinum, the preparation method comprising the following steps:

[0006] Step S1, performing direct chlorination reaction on platinum powder, hydrochloric acid and chlorine gas to obtain chloroplatinic acid solution;

[0007] Step S2, boiling the chloroplatinic acid solution and filtering it to obtain a chloroplatinic acid filtrate;

[0008] Step S3, passing the chloroplatinic acid filtrate into a cation exchange resin for adsorption to obtain a purified chloroplatinic acid solution;

[0009] Step S4, passing sulfur dioxide into the purified chloroplatinic acid solution for reaction, and filtering to obtain a chloroplatinous acid solution;

[0010] Step S5, adding hydrazine hydrate dropwise to a chloroplatinous acid solution adjusted to an alkaline pH to react and obtain sponge platinum;

[0011] Step S6: washing the sponge platinum with hot water, acid washing and hot water washing twice in sequence, and drying to obtain high-purity platinum.

[0012] Preferably, the mass volume ratio of the platinum powder to hydrochloric acid is 1kg:5~15L, and the mass volume ratio of the platinum powder to chlorine is 1kg:5~50L / min;

[0013] The mass volume ratio of the platinum powder and the cation exchange resin is 1kg:100mL~1000mL;

[0014] The mass volume ratio of the platinum powder and sulfur dioxide is 1kg:5~50L / min;

[0015] The mass volume ratio of the platinum powder and hydrazine hydrate is 1kg:250-750mL;

[0016] The mass volume ratio of the platinum powder and the acid used for pickling is 1kg:3~9L.

[0017] Preferably, in step S3, the flow rate of the chloroplatinic acid filtrate is 100-500 mL / h.

[0018] Preferably, in step S3, the flow rate of the chloroplatinic acid filtrate is 300-500 mL / h.

[0019] Preferably, in step S4, the flow rate of sulfur dioxide is 5-50 L / min, and the time is 1-3 h.

[0020] Preferably, in step S4, the flow rate of sulfur dioxide is 25-50 L / min, and the time is 1-3 h.

[0021] Preferably, in step S5, the chloroplatinous acid solution whose pH is adjusted to alkaline is a chloroplatinous acid solution whose pH is adjusted to 8-12.

[0022] Preferably, in step S5, the chloroplatinous acid solution whose pH is adjusted to alkaline is a chloroplatinous acid solution whose pH is adjusted to 8-10.

[0023] Preferably, in step S1, the temperature of the direct chlorination reaction is 60-105° C. and the time is 2-6 hours.

[0024] Preferably, in step S2, the boiling time is 15 to 60 minutes.

[0025] Preferably, in step S4, the temperature at which sulfur dioxide is introduced into the purified chloroplatinic acid solution for reaction is 70-100°C.

[0026] Preferably, in step S5, the temperature of adding hydrazine hydrate dropwise to the chloroplatinous acid solution adjusted to an alkaline pH for reaction is 70-100° C. and the reaction time is 1-3 h.

[0027] Preferably, in step S6, the hot water temperature used for the hot water washing and the secondary hot water washing is 60-90°C.

[0028] The pickling is performed by boiling nitric acid with a concentration of 10-50% for 30-90 minutes;

[0029] The drying temperature is 100-300° C. and the drying time is 2-6 hours.

[0030] The second aspect of the present application provides the application of high-purity platinum prepared by the method for preparing high-purity platinum described in the first aspect in the optical field or the integrated circuit field.

[0031] Compared with the prior art, the method for preparing high-purity platinum provided in the present application has at least the following beneficial effects:

[0032] 1. In a method for preparing high-purity platinum provided in the present application, high-purity platinum can be prepared through direct chlorination treatment, boiling and filtering treatment, cation exchange resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment steps, hot water washing and acid washing steps; and there is no need to use the repeated precipitation method of ammonium chloroplatinate, no large amount of ammonia nitrogen wastewater is generated, and the expensive equipment required by the regional smelting method is not required. The method has low cost and is suitable for large-scale industrial production of high-purity platinum.

[0033] 2. In a method for preparing high-purity platinum provided in the present application, a high-purity platinum product with a purity of 5N (99.999%) or above can be prepared by strengthening the sulfur dioxide treatment process.

[0034] 3. In the method for preparing high-purity platinum provided in the present application, high-purity platinum with a yield of more than 99.9% can be prepared by adjusting the hydrazine hydrate treatment process. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 A schematic flow chart of a method for preparing high-purity platinum provided in an embodiment of the present application. DETAILED DESCRIPTION

[0037] The present application provides a preparation method and application of high-purity platinum, which are used to solve the technical problem of lack of preparation method of high-purity platinum in the prior art.

[0038] The technical solution of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0039] In view of the fact that the current method of repeated precipitation of ammonium chloroplatinate and the physical method of regional smelting for preparing high-purity platinum are difficult to be widely used in actual industrial production, and there is a lack of a method for preparing high-purity platinum; the present application provides a method for preparing high-purity platinum, which comprises the following steps: firstly, directly chlorinating platinum powder, hydrochloric acid and chlorine to obtain a chloroplatinic acid solution, then boiling the chloroplatinic acid solution and filtering to obtain a chloroplatinic acid filtrate, then passing the chloroplatinic acid filtrate into a cation exchange resin for adsorption to obtain a purified chloroplatinic acid solution, then passing sulfur dioxide into the purified chloroplatinic acid solution for reaction to obtain a chloroplatinous acid solution, and then dropping hydrazine hydrate into the chloroplatinous acid solution adjusted to alkaline pH to react to obtain sponge platinum; then sequentially washing the sponge platinum with hot water, acid washing and washing it with hot water twice, and then drying it to obtain high-purity platinum.

[0040] The present application provides a method for preparing high-purity platinum. The reaction formula of the direct chlorination reaction step using platinum powder, hydrochloric acid and chlorine gas is Pt+2Cl2+2HCl= H2PtCl6. In this step, low-purity platinum powder is successfully converted into chloroplatinic acid. Unreacted impurities can be removed by boiling and filtering. The chloroplatinic acid filtrate is then passed through a cation exchange resin for adsorption to remove base metal impurities to obtain a purified chloroplatinic acid solution. Subsequently, sulfur dioxide is passed through and hydrazine hydrate is added dropwise to purify the chloroplatinic acid solution to obtain sponge platinum. The reaction formulas for the steps of passing sulfur dioxide and adding hydrazine hydrate to form sponge platinum are H2PtCl6+SO2+2H2O=H2PtCl4+ H2SO4+2HCl and 2H2PtCl4+ N2H4= N2↑+ 2Pt↓+8HCl, and sulfur dioxide reduction can also remove some anionic impurities, and the purity of chloroplatinous acid is improved after filtration, and the purity of the product sponge platinum is improved; the following hot water washing, acid washing and secondary hot water washing steps can remove impurity ions such as residual chlorine in the sponge platinum to obtain sponge platinum with higher purity. The present application provides a method for preparing high-purity platinum, which does not introduce impurities in each process step, does not require the use of repeated precipitation methods of ammonium chloroplatinate, does not generate a large amount of ammonia nitrogen wastewater, and has low requirements on production equipment, and is suitable for large-scale industrial production of high-purity platinum.

[0041] Preferably, in a method for preparing high-purity platinum provided in the present application, in order to improve the yield and purity of platinum, it is necessary to control the amount of platinum powder raw material and reagents used in each reaction step. For every 1 kg of platinum powder processed, 5 to 15 L of hydrochloric acid (concentration 35% to 38%) is required in the direct chlorination reaction step, and 5 to 50 L / min of chlorine is introduced. In the cation exchange resin adsorption step, 100 mL to 1000 mL of cation exchange resin (Sinopharm Komeo, 732 type cation exchange resin) is required. In the sulfur dioxide and hydrazine hydrate treatment step, 5 to 50 L / min of sulfur dioxide is required, and 250 to 750 mL of hydrazine hydrate (content ≥ 80%) is added, and the amount of acid used for pickling is 1 kg: 3 to 9 L.

[0042] Preferably, in a method for preparing high-purity platinum provided in the present application, in the cation exchange resin adsorption step, the flow rate of the chloroplatinic acid filtrate introduced will affect the adsorption effect and the purity of the product high-purity platinum. When the flow rate of the chloroplatinic acid filtrate is 500 mL / h, the adsorption effect is poor and the purity of the high-purity platinum is not high. When the flow rate of the chloroplatinic acid filtrate is reduced to 100~300 mL / h, the adsorption effect is better and the purity of the product high-purity platinum is improved.

[0043] Preferably, in a method for preparing high-purity platinum provided in the present application, in the step of introducing sulfur dioxide for treatment, sulfur dioxide can not only reduce chloroplatinic acid to chloroplatinous acid, but also remove some anions, so that when the flow rate of sulfur dioxide introduced is low, for example 5 L / min, the purity of the product is low, while introducing a higher flow rate, such as introducing sulfur dioxide at a flow rate of 25~50 L / min, will better improve the purity of the product high-purity platinum.

[0044] Preferably, in a method for preparing high-purity platinum provided by the present application, in the step of dripping hydrazine hydrate for treatment, controlling the reaction system under alkaline conditions can improve the yield of the product high-purity platinum. From the aspect of yield, the present application controls and adjusts the pH of the reaction system to 8-12; on the other hand, although the higher the pH, the higher the yield of the product high-purity platinum, the sodium hydroxide used to adjust the pH to alkaline will reduce the purity of the product high-purity platinum. In addition to removing impurities in the subsequent pickling process, from the aspect of purity, the present application should control and adjust the pH of the reaction system to 8-10.

[0045] At the same time, after high-purity platinum is prepared by a preparation method of high-purity platinum provided in the present application, the purity can reach 5N (99.999%) or above, thereby meeting the application requirements in the optical field or the integrated circuit field.

[0046] The following is a detailed description of a method for preparing high-purity platinum provided in the present application in combination with embodiments and experimental examples.

[0047] Example 1

[0048] Example 1 of the present application provides a method for preparing high-purity platinum, which includes the steps of direct chlorination reaction, boiling and filtering treatment, resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, and hot water / acid washing.

[0049] The steps of direct chlorination reaction include: measuring 1000 ml of 36% hydrochloric acid and placing it in a 2L glass reactor, stirring, weighing 100 g of raw platinum powder with a purity of 99.97% and adding it to the hydrochloric acid, heating it to 60-105° C., introducing chlorine gas at a flow rate of 2.5 L / min; maintaining the temperature at 60-105° C. and reacting until the platinum powder is completely dissolved, stopping the introduction of chlorine gas, and obtaining a chloroplatinic acid solution.

[0050] The steps of boiling and filtering treatment include: after stopping the chlorine gas, continuing to heat to boiling for 30 minutes, and then filtering the chloroplatinic acid solution to obtain a chloroplatinic acid filtrate.

[0051] The resin adsorption treatment step includes: cooling the chloroplatinic acid filtrate and subjecting it to adsorption treatment with 100 ml of cation exchange resin at a flow rate of 500 ml / h to obtain a purified chloroplatinic acid solution.

[0052] The sulfur dioxide treatment step includes: heating the purified chloroplatinic acid solution to 70°C, controlling the flow rate to 0.5L / min, passing sulfur dioxide for reduction for 1h, cooling to room temperature and filtering to obtain a chloroplatinous acid solution.

[0053] The step of hydrazine hydrate treatment includes: adjusting the pH of chloroplatinous acid solution to 8 with sodium hydroxide, heating to 70°C, dropping 25 ml of 80% hydrazine hydrate, controlling the dropping time to 2h, controlling the pH of the reduction process to 8, cooling to room temperature after the reduction is completed, and filtering to obtain sponge platinum.

[0054] The hot water / acid washing step includes: washing the sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the filtrate is free of chloride ions by silver nitrate detection, then placing the sponge platinum washed with hot water in 300ml of 10% nitric acid and heating and boiling for 30min, and then washing the sponge platinum after acid washing with 0.5-3L of hot water at a temperature of 60-90°C until the pH is ≥ 6. The platinum powder is dried at 200°C in a nitrogen atmosphere for 6h to obtain high-purity platinum.

[0055] Example 2

[0056] Example 2 of the present application provides a method for preparing high-purity platinum, which adjusts the sulfur dioxide treatment process and includes the steps of direct chlorination reaction, boiling and filtration treatment, resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, and hot water / acid washing.

[0057] The steps of direct chlorination reaction include: measuring 1000 ml of 36% hydrochloric acid and placing it in a 2L glass reactor, stirring, weighing 100 g of raw platinum powder with a purity of 99.97% and adding it to the hydrochloric acid, heating it to 60-105° C., introducing chlorine gas at a flow rate of 2.5 L / min; maintaining the temperature at 60-105° C. and reacting until the platinum powder is completely dissolved, stopping the introduction of chlorine gas, and obtaining a chloroplatinic acid solution.

[0058] The steps of boiling and filtering treatment include: after stopping the chlorine gas, continuing to heat to boiling for 30 minutes, and then filtering the chloroplatinic acid solution to obtain a chloroplatinic acid filtrate.

[0059] The resin adsorption treatment step includes: cooling the chloroplatinic acid filtrate and subjecting it to adsorption treatment with 100 ml of cation exchange resin at a flow rate of 500 ml / h to obtain a purified chloroplatinic acid solution.

[0060] The sulfur dioxide treatment step includes: heating the purified chloroplatinic acid solution to 85°C, controlling the flow rate to 2.5L / min, passing sulfur dioxide for reduction for 2h, cooling to room temperature and filtering to obtain a chloroplatinous acid solution.

[0061] The step of hydrazine hydrate treatment includes: adjusting the pH of chloroplatinous acid solution to 8 with sodium hydroxide, heating to 70°C, dropping 25 ml of 80% hydrazine hydrate, controlling the dropping time to 2h, controlling the pH of the reduction process to 8, cooling to room temperature after the reduction is completed, and filtering to obtain sponge platinum.

[0062] The hot water / acid washing step includes: washing the sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the filtrate is free of chloride ions by silver nitrate detection, then placing the sponge platinum washed with hot water in 300ml of 10% nitric acid and heating and boiling for 30min, and then washing the sponge platinum after acid washing with 0.5-3L of hot water at a temperature of 60-90°C until the pH is ≥ 6. The platinum powder is dried at 200°C in a nitrogen atmosphere for 6h to obtain high-purity platinum.

[0063] Example 3

[0064] Example 3 of the present application provides a method for preparing high-purity platinum, which adjusts the sulfur dioxide treatment process and includes the steps of direct chlorination reaction, boiling and filtration treatment, resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, and hot water / acid washing.

[0065] The steps of direct chlorination reaction include: measuring 1000 ml of 36% hydrochloric acid and placing it in a 2L glass reactor, stirring, weighing 100 g of raw platinum powder with a purity of 99.97% and adding it to the hydrochloric acid, heating it to 60-105° C., introducing chlorine gas at a flow rate of 2.5 L / min; maintaining the temperature at 60-105° C. and reacting until the platinum powder is completely dissolved, stopping the introduction of chlorine gas, and obtaining a chloroplatinic acid solution.

[0066] The steps of boiling and filtering treatment include: after stopping the chlorine gas, continuing to heat to boiling for 30 minutes, and then filtering the chloroplatinic acid solution to obtain a chloroplatinic acid filtrate.

[0067] The resin adsorption treatment step includes: cooling the chloroplatinic acid filtrate and subjecting it to adsorption treatment with 100 ml of cation exchange resin at a flow rate of 500 ml / h to obtain a purified chloroplatinic acid solution.

[0068] The sulfur dioxide treatment step includes: heating the purified chloroplatinic acid solution to 100°C, controlling the flow rate to 5L / min, passing sulfur dioxide for reduction for 3h, cooling to room temperature and filtering to obtain a chloroplatinous acid solution.

[0069] The step of hydrazine hydrate treatment includes: adjusting the pH of chloroplatinous acid solution to 8 with sodium hydroxide, heating to 70°C, dropping 25 ml of 80% hydrazine hydrate, controlling the dropping time to 2h, controlling the pH of the reduction process to 8, cooling to room temperature after the reduction is completed, and filtering to obtain sponge platinum.

[0070] The hot water / acid washing step includes: washing the sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the filtrate is free of chloride ions by silver nitrate detection, then placing the sponge platinum washed with hot water in 300ml of 10% nitric acid and heating and boiling for 30min, and then washing the sponge platinum after acid washing with 0.5-3L of hot water at a temperature of 60-90°C until the pH is ≥ 6. The platinum powder is dried at 200°C in a nitrogen atmosphere for 6h to obtain high-purity platinum.

[0071] Example 4

[0072] Example 4 of the present application provides a method for preparing high-purity platinum, which adjusts the resin adsorption treatment step and the sulfur dioxide treatment process, including the steps of direct chlorination reaction, boiling and filtration treatment, resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, and hot water / acid washing.

[0073] The steps of direct chlorination reaction include: measuring 1000 ml of 36% hydrochloric acid and placing it in a 2L glass reactor, stirring, weighing 100 g of raw platinum powder with a purity of 99.97% and adding it to the hydrochloric acid, heating it to 60-105° C., introducing chlorine gas at a flow rate of 2.5 L / min; maintaining the temperature at 60-105° C. and reacting until the platinum powder is completely dissolved, stopping the introduction of chlorine gas, and obtaining a chloroplatinic acid solution.

[0074] The steps of boiling and filtering treatment include: after stopping the chlorine gas, continuing to heat to boiling for 30 minutes, and then filtering the chloroplatinic acid solution to obtain a chloroplatinic acid filtrate.

[0075] The resin adsorption treatment step includes: cooling the chloroplatinic acid filtrate and subjecting it to adsorption treatment with 100 ml of cation exchange resin at a flow rate of 300 ml / h to obtain a purified chloroplatinic acid solution.

[0076] The sulfur dioxide treatment step includes: heating the purified chloroplatinic acid solution to 100°C, controlling the flow rate to 5L / min, passing sulfur dioxide for reduction for 3h, cooling to room temperature and filtering to obtain a chloroplatinous acid solution.

[0077] The step of hydrazine hydrate treatment includes: adjusting the pH of chloroplatinous acid solution to 8 with sodium hydroxide, heating to 70°C, dropping 25 ml of 80% hydrazine hydrate, controlling the dropping time to 2h, controlling the pH of the reduction process to 8, cooling to room temperature after the reduction is completed, and filtering to obtain sponge platinum.

[0078] The hot water / acid washing step includes: washing the sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the filtrate is free of chloride ions by silver nitrate detection, then placing the sponge platinum washed with hot water in 300ml of 10% nitric acid and heating and boiling for 30min, and then washing the sponge platinum after acid washing with 0.5-3L of hot water at a temperature of 60-90°C until the pH is ≥ 6. The platinum powder is dried at 200°C in a nitrogen atmosphere for 6h to obtain high-purity platinum.

[0079] Example 5

[0080] Example 5 of the present application provides a method for preparing high-purity platinum, which adjusts the resin adsorption treatment and sulfur dioxide treatment processes, including the steps of direct chlorination reaction, boiling and filtration treatment, resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, and hot water / acid washing.

[0081] The steps of direct chlorination reaction include: measuring 1000 ml of 36% hydrochloric acid and placing it in a 2L glass reactor, stirring, weighing 100 g of raw platinum powder with a purity of 99.97% and adding it to the hydrochloric acid, heating it to 60-105° C., introducing chlorine gas at a flow rate of 2.5 L / min; maintaining the temperature at 60-105° C. and reacting until the platinum powder is completely dissolved, stopping the introduction of chlorine gas, and obtaining a chloroplatinic acid solution.

[0082] The steps of boiling and filtering treatment include: after stopping the chlorine gas, continuing to heat to boiling for 30 minutes, and then filtering the chloroplatinic acid solution to obtain a chloroplatinic acid filtrate.

[0083] The resin adsorption treatment step includes: cooling the chloroplatinic acid filtrate and subjecting it to adsorption treatment with 100 ml of cation exchange resin at a flow rate of 100 ml / h to obtain a purified chloroplatinic acid solution.

[0084] The sulfur dioxide treatment step includes: heating the purified chloroplatinic acid solution to 100°C, controlling the flow rate to 2.5L / min, reducing with sulfur dioxide for 3h, cooling to room temperature and filtering to obtain a chloroplatinous acid solution.

[0085] The step of hydrazine hydrate treatment includes: adjusting the pH of chloroplatinous acid solution to 8 with sodium hydroxide, heating to 70°C, dropping 25 ml of 80% hydrazine hydrate, controlling the dropping time to 2h, controlling the pH of the reduction process to 8, cooling to room temperature after the reduction is completed, and filtering to obtain sponge platinum.

[0086] The hot water / acid washing step includes: washing the sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the filtrate is free of chloride ions by silver nitrate detection, then placing the sponge platinum washed with hot water in 300ml of 10% nitric acid and heating and boiling for 30min, and then washing the sponge platinum after acid washing with 0.5-3L of hot water at a temperature of 60-90°C until the pH is ≥ 6. The platinum powder is dried at 200°C in a nitrogen atmosphere for 6h to obtain high-purity platinum.

[0087] Example 6

[0088] Example 6 of the present application provides a method for preparing high-purity platinum, which adjusts the resin adsorption treatment, sulfur dioxide treatment and acid washing process, including the steps of direct chlorination reaction, boiling and filtration treatment, resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, and hot water / acid washing.

[0089] The steps of direct chlorination reaction include: measuring 1000 ml of 36% hydrochloric acid and placing it in a 2L glass reactor, stirring, weighing 100 g of raw platinum powder with a purity of 99.97% and adding it to the hydrochloric acid, heating it to 60-105° C., introducing chlorine gas at a flow rate of 2.5 L / min; maintaining the temperature at 60-105° C. and reacting until the platinum powder is completely dissolved, stopping the introduction of chlorine gas, and obtaining a chloroplatinic acid solution.

[0090] The steps of boiling and filtering treatment include: after stopping the chlorine gas, continuing to heat to boiling for 30 minutes, and then filtering the chloroplatinic acid solution to obtain a chloroplatinic acid filtrate.

[0091] The resin adsorption treatment step includes: cooling the chloroplatinic acid filtrate and subjecting it to adsorption treatment with 100 ml of cation exchange resin at a flow rate of 300 ml / h to obtain a purified chloroplatinic acid solution.

[0092] The sulfur dioxide treatment step includes: heating the purified chloroplatinic acid solution to 100°C, controlling the flow rate to 2.5L / min, passing sulfur dioxide for reduction for 3h, cooling to room temperature and filtering to obtain a chloroplatinous acid solution.

[0093] The step of hydrazine hydrate treatment includes: adjusting the pH of chloroplatinous acid solution to 8 with sodium hydroxide, heating to 70°C, dropping 25 ml of 80% hydrazine hydrate, controlling the dropping time to 2h, controlling the pH of the reduction process to 8, cooling to room temperature after the reduction is completed, and filtering to obtain sponge platinum.

[0094] The hot water / acid washing step includes: washing the sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the filtrate is free of chloride ions by silver nitrate detection, then placing the sponge platinum washed with hot water in 300ml of 10% nitric acid and heating and boiling for 60min, and then washing the acid-washed sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the pH is ≥ 6. The platinum powder is dried at 200°C in a nitrogen atmosphere for 6h to obtain high-purity platinum.

[0095] Example 7

[0096] Example 7 of the present application provides a method for preparing high-purity platinum, which adjusts the resin adsorption treatment, sulfur dioxide treatment and acid washing process, including the steps of direct chlorination reaction, boiling and filtration treatment, resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, and hot water / acid washing.

[0097] The steps of direct chlorination reaction include: measuring 1000 ml of 36% hydrochloric acid and placing it in a 2L glass reactor, stirring, weighing 100 g of raw platinum powder with a purity of 99.97% and adding it to the hydrochloric acid, heating it to 60-105° C., introducing chlorine gas at a flow rate of 2.5 L / min; maintaining the temperature at 60-105° C. and reacting until the platinum powder is completely dissolved, stopping the introduction of chlorine gas, and obtaining a chloroplatinic acid solution.

[0098] The steps of boiling and filtering treatment include: after stopping the chlorine gas, continuing to heat to boiling for 30 minutes, and then filtering the chloroplatinic acid solution to obtain a chloroplatinic acid filtrate.

[0099] The resin adsorption treatment step includes: cooling the chloroplatinic acid filtrate and subjecting it to adsorption treatment with 100 ml of cation exchange resin at a flow rate of 300 ml / h to obtain a purified chloroplatinic acid solution.

[0100] The sulfur dioxide treatment step includes: heating the purified chloroplatinic acid solution to 100°C, controlling the flow rate to 2.5L / min, passing sulfur dioxide for reduction for 3h, cooling to room temperature and filtering to obtain a chloroplatinous acid solution.

[0101] The step of hydrazine hydrate treatment includes: adjusting the pH of chloroplatinous acid solution to 8 with sodium hydroxide, heating to 70°C, dropping 25 ml of 80% hydrazine hydrate, controlling the dropping time to 2h, controlling the pH of the reduction process to 8, cooling to room temperature after the reduction is completed, and filtering to obtain sponge platinum.

[0102] The hot water / acid washing step includes: washing the sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the filtrate is free of chloride ions by silver nitrate detection, then placing the sponge platinum washed with hot water in 300ml of 10% nitric acid and heating and boiling for 90min, and then washing the acid-washed sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the pH is ≥ 6. The platinum powder is dried at 200°C in a nitrogen atmosphere for 6h to obtain high-purity platinum.

[0103] Example 8

[0104] Example 8 of the present application provides a method for preparing high-purity platinum, which adjusts the resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment and pickling process, including the steps of direct chlorination reaction, boiling and filtration treatment, resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, and hot water / pickling.

[0105] The steps of direct chlorination reaction include: measuring 1000 ml of 36% hydrochloric acid and placing it in a 2L glass reactor, stirring, weighing 100 g of raw platinum powder with a purity of 99.97% and adding it to the hydrochloric acid, heating it to 60-105° C., introducing chlorine gas at a flow rate of 2.5 L / min; maintaining the temperature at 60-105° C. and reacting until the platinum powder is completely dissolved, stopping the introduction of chlorine gas, and obtaining a chloroplatinic acid solution.

[0106] The steps of boiling and filtering treatment include: after stopping the chlorine gas, continuing to heat to boiling for 30 minutes, and then filtering the chloroplatinic acid solution to obtain a chloroplatinic acid filtrate.

[0107] The resin adsorption treatment step includes: cooling the chloroplatinic acid filtrate and subjecting it to adsorption treatment with 100 ml of cation exchange resin at a flow rate of 300 ml / h to obtain a purified chloroplatinic acid solution.

[0108] The sulfur dioxide treatment step includes: heating the purified chloroplatinic acid solution to 100°C, controlling the flow rate to 5L / min, passing sulfur dioxide for reduction for 3h, cooling to room temperature and filtering to obtain a chloroplatinous acid solution.

[0109] The step of hydrazine hydrate treatment includes: adjusting the pH of chloroplatinous acid solution to 10 with sodium hydroxide, heating to 70°C, dropping 50 ml of 80% hydrazine hydrate, controlling the dropping time to 2h, controlling the pH of the reduction process to 8, cooling to room temperature after the reduction is completed, and filtering to obtain sponge platinum.

[0110] The hot water / acid washing step includes: washing the sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the filtrate is free of chloride ions by silver nitrate detection, then placing the sponge platinum washed with hot water in 300ml of 10% nitric acid and heating and boiling for 60min, and then washing the acid-washed sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the pH is ≥ 6. The platinum powder is dried at 200°C in a nitrogen atmosphere for 6h to obtain high-purity platinum.

[0111] Example 9

[0112] Example 9 of the present application provides a method for preparing high-purity platinum, which adjusts the resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment and pickling process, including the steps of direct chlorination reaction, boiling and filtration treatment, resin adsorption treatment, sulfur dioxide treatment, hydrazine hydrate treatment, and hot water / pickling.

[0113] The steps of direct chlorination reaction include: measuring 1000 ml of 36% hydrochloric acid and placing it in a 2L glass reactor, stirring, weighing 100 g of raw platinum powder with a purity of 99.97% and adding it to the hydrochloric acid, heating it to 60-105° C., introducing chlorine gas at a flow rate of 2.5 L / min; maintaining the temperature at 60-105° C. and reacting until the platinum powder is completely dissolved, stopping the introduction of chlorine gas, and obtaining a chloroplatinic acid solution.

[0114] The steps of boiling and filtering treatment include: after stopping the chlorine gas, continuing to heat to boiling for 30 minutes, and then filtering the chloroplatinic acid solution to obtain a chloroplatinic acid filtrate.

[0115] The resin adsorption treatment step includes: cooling the chloroplatinic acid filtrate and subjecting it to adsorption treatment with 100 ml of cation exchange resin at a flow rate of 300 ml / h to obtain a purified chloroplatinic acid solution.

[0116] The sulfur dioxide treatment step includes: heating the purified chloroplatinic acid solution to 100°C, controlling the flow rate to 5L / min, passing sulfur dioxide for reduction for 3h, cooling to room temperature and filtering to obtain a chloroplatinous acid solution.

[0117] The step of hydrazine hydrate treatment includes: adjusting the pH of chloroplatinous acid solution to 12 with sodium hydroxide, heating to 70°C, dripping 75 ml of 80% hydrazine hydrate, controlling the dripping time to 2h, controlling the pH of the reduction process to 8, cooling to room temperature after the reduction is completed, and filtering to obtain sponge platinum.

[0118] The hot water / acid washing step includes: washing the sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the filtrate is free of chloride ions by silver nitrate detection, then placing the sponge platinum washed with hot water in 300ml of 10% nitric acid and heating and boiling for 60min, and then washing the acid-washed sponge platinum with 0.5-3L of hot water at a temperature of 60-90°C until the pH is ≥ 6. The platinum powder is dried at 200°C in a nitrogen atmosphere for 6h to obtain high-purity platinum.

[0119] Experimental Example 1

[0120] In this experimental example, an inductively coupled plasma mass spectrometer (ICP-MS) was used to perform purity analysis on the high purity platinum prepared in Examples 1-9. The high purity platinum prepared in Examples 1-9 was also weighed and the yield was calculated. The purity and yield of the high purity platinum prepared in Examples 1-9 are shown in Table 1.

[0121] Table 1: Purity and yield of high purity platinum

[0122]

[0123] It can be seen from the results shown in Table 1 that, compared with the raw platinum powder with a purity of 99.97%, the method provided in the present application can prepare high-purity platinum through direct chlorination treatment, boiling and filtering, cation exchange resin adsorption treatment, sulfur dioxide, hydrazine hydrate treatment steps, hot water washing and acid washing and other steps.

[0124] It can be further seen from the results shown in Table 1 that the purity of the high-purity platinum products prepared in Example 1 and Example 2 is not very high, while in Examples 3-9, after adjusting the sulfur dioxide treatment process, high-purity platinum products with a purity of 5N (99.999%) or above were prepared; this is because sulfur dioxide can not only reduce chloroplatinic acid to chloroplatinous acid, but also remove some anionic impurities. Increasing the flow rate and extending the time can improve the removal effect of anionic impurities.

[0125] It can also be seen from the results shown in Table 1 that the yield of high-purity platinum products prepared in Examples 1-7 is not high, at around 99.3%, while in Examples 8-9, after adjusting the hydrazine hydrate treatment process, the yield of high-purity platinum is above 99.9%; this is because alkaline conditions can increase the yield of high-purity platinum products, and the higher the pH, the higher the yield of high-purity platinum products.

[0126] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for preparing high-purity platinum, characterized in that: The following steps are involved: Step S1, performing direct chlorination reaction on platinum powder, hydrochloric acid and chlorine gas to obtain chloroplatinic acid solution; Step S2, boiling the chloroplatinic acid solution and filtering it to obtain a chloroplatinic acid filtrate; Step S3, passing the chloroplatinic acid filtrate into a cation exchange resin for adsorption to obtain a purified chloroplatinic acid solution; Step S4, passing sulfur dioxide into the purified chloroplatinic acid solution for reaction, and filtering to obtain a chloroplatinous acid solution; Step S5, adding hydrazine hydrate dropwise to a chloroplatinous acid solution adjusted to an alkaline pH to react and obtain sponge platinum; Step S6: washing the sponge platinum with hot water, acid washing and hot water washing twice in sequence, and drying to obtain high-purity platinum.

2. The method for preparing high-purity platinum according to claim 1, characterized in that: The mass volume ratio of the platinum powder to the hydrochloric acid is 1kg:5~15L, and the mass volume ratio of the platinum powder to the chlorine gas is 1kg:5~50L / min; The mass volume ratio of the platinum powder to the cation exchange resin is 1 kg: 100 mL to 1000 mL; The mass volume ratio of the platinum powder to the sulfur dioxide is 1kg:5~50L / min; The mass volume ratio of the platinum powder to the hydrazine hydrate is 1 kg: 250-750 mL; The mass volume ratio of the platinum powder to the acid used for pickling is 1kg:3~9L.

3. The method for preparing high-purity platinum according to claim 1, characterized in that: In step S3, the flow rate of the chloroplatinic acid filtrate is 100-500 mL / h.

4. The method for preparing high-purity platinum according to claim 3, characterized in that: In step S3, the flow rate of the chloroplatinic acid filtrate is 300-500 mL / h.

5. The method for preparing high-purity platinum according to claim 1, characterized in that: In step S4, the flow rate of sulfur dioxide is 5-50 L / min, and the time is 1-3 h.

6. The method for preparing high-purity platinum according to claim 1, characterized in that: In step S4, the flow rate of sulfur dioxide is 25-50 L / min, and the time is 1-3 h.

7. The method for preparing high-purity platinum according to claim 1, characterized in that: In step S5, the chloroplatinous acid solution whose pH is adjusted to alkaline is a chloroplatinous acid solution whose pH is adjusted to 8-12.

8. The method for preparing high-purity platinum according to claim 1, characterized in that: In step S5, the chloroplatinous acid solution whose pH is adjusted to alkaline is a chloroplatinous acid solution whose pH is adjusted to 8-10.

9. The method for preparing high-purity platinum according to claim 1, characterized in that: In step S6, the pickling is performed by boiling nitric acid with a concentration of 10-50% for a washing time of 30-90 minutes.

10. Application of high-purity platinum prepared by the method for preparing high-purity platinum according to any one of claims 1 to 9 in the field of optics or integrated circuits.

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