Platinum metal recovery method based on ion exchange process

Abstract

The invention discloses a platinum metal recovery method based on an ion exchange process, which comprises the following steps: S1, adding 1.5-2.5 times of water into platinum-containing waste liquid, stirring for 10-20 minutes, precipitating for 2-3 hours, filtering to obtain filtrate and filter residues, and roasting the filter residues at the constant temperature of 380-420 DEG C for 4-5 hours; s2, after roasting, filter residues are naturally cooled to the room temperature, the cooled filter residues are ground into powder, the ground filter residues are screened through a screen, and the filter residues with the particle size being 200-300 meshes are selected. The invention belongs to the technical field of platinum metal recovery, and aims to solve the problem that the chloride ion concentration in platinum-containing liquid and the speed of injecting the platinum-containing liquid into a resin bed are inconvenient to accurately control in the prior art. The technical effects are that the acidity and chloride ion concentration of the solution can be adjusted according to the concentrated hydrochloric acid and the oxidant, and the flow rate of the platinum-containing liquid passing through the resin bed is controlled, so that the platinum-containing liquid is in full contact with the resin bed, and the adsorption effect of the resin bed on platinum metal is improved.

Description

Technical Field

[0001] The invention relates to the technical field of platinum metal recovery, and in particular to a method for recovering platinum metal based on an ion exchange process. Background Art

[0002] Platinum metal is widely used in the fields of catalysts, sensors, anti-cancer drugs, petroleum refining, electronic equipment manufacturing, etc. It can be used to produce computer hard disks to increase the storage capacity of multilayer ceramic capacitors and hybrid integrated circuits; produce glass for the manufacture of liquid crystal displays and as a dental repair material; currently, the main methods for the recovery and refining of platinum metal include chemical recovery, precipitation recovery and ion exchange resin method, among which the ion exchange resin method has a higher recovery rate. Chemical recovery includes pyrolysis and wet method. Pyrolysis involves high-temperature treatment, and wet method separates platinum elements by dissolving waste materials; precipitation recovery is suitable for low-concentration platinum waste, and platinum is precipitated and separated by adding chemicals;

[0003] The method of recovering platinum metal by ion exchange resin is to adsorb platinum metal by ion exchange resin, then desorb the adsorbed platinum metal from the resin by elution step to form a solution containing platinum metal, and then purify and refine the eluate to obtain a high-purity platinum product; however, most of the methods for recovering platinum metal by ion exchange process are not convenient for accurately controlling the chloride ion concentration in the platinum-containing solution and the speed of injecting the platinum-containing solution into the resin bed during the adsorption of platinum metal by ion exchange resin, which is easy to affect the subsequent adsorption effect of platinum metal on the resin bed. Summary of the invention

[0004] To this end, the present invention provides a method for recovering platinum metal based on an ion exchange process to solve the above-mentioned problems in the prior art.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] According to a first aspect of the present invention, a method for recovering platinum metal based on an ion exchange process comprises the following steps:

[0007] S1: adding 1.5-2.5 times of water to the platinum-containing waste liquid, stirring for 10-20 minutes, settling for 2-3 hours and filtering to obtain a filtrate and a filter residue, and calcining the filter residue at a constant temperature of 380-420° C. for 4-5 hours;

[0008] S2: After calcination, the filter residue is naturally cooled to room temperature, the cooled filter residue is ground into powder, the ground filter residue is screened through a sieve, and the filter residue with a particle size of 200-300 mesh is selected, and the powder is added to the filtrate in S1, and then dilute hydrochloric acid with a concentration of 10%-15% is added, and stirred at 35-60°C for 5-10 minutes, the solution Ph is controlled to be 6-8, and the solution is precipitated for 1-2 hours and filtered to obtain platinum-containing slag and dry it;

[0009] S3: adding 1.5-3 times of concentrated sulfuric acid to the dried platinum-containing slag to dissolve the platinum-containing slag with the concentrated sulfuric acid for 1.5-3 hours at a dissolution temperature of 90-130° C., controlling the Ph of the platinum-containing solution to be 2-11, and then adding concentrated hydrochloric acid and an oxidant to dissolve the platinum, stirring at the same time to ensure full contact, filtering, separating the unreacted solid residue from the platinum-containing solution, and obtaining the platinum-containing solution;

[0010] S4: Inject the platinum-containing solution into an ion exchange column equipped with a resin bed at a flow rate of 4-7 BV / hour. The ion exchange resin is CH-97, adsorption time is 1-1.5 hours, adsorption humidity is 40%-50%;

[0011] S5: After the resin bed is saturated with adsorption, an eluent with a concentration of 15%-20% is used, and the eluent is preheated to 20-55°C, and the adsorbed platinum group metal ions are replaced and eluted by the eluent to obtain a platinum-containing eluent;

[0012] S6: Add a reducing agent to the platinum-containing eluent at 80-100°C for a reaction time of 0.8-1 hour. After the reaction is completed, quickly cool to room temperature, filter to remove insoluble residues, collect the filtrate, and calcine at 680-700°C to obtain a platinum metal product, and then regenerate the resin bed in the ion exchange column.

[0013] Furthermore, the mass ratio of the total mass of the dilute hydrochloric acid to the mass of the filtrate is 0.5:3-5.

[0014] Furthermore, the concentration of the concentrated hydrochloric acid is 35%-38%, the oxidant is hydrogen peroxide, the mass ratio of concentrated hydrochloric acid to platinum-containing slag is 1:0.5-2.5, the mass ratio of hydrogen peroxide to platinum-containing slag is 1:0.1-0.2, and the reaction time is 8-9 hours.

[0015] Furthermore, the reducing agent is a 25%-30% sodium bisulfite solution.

[0016] Further, the resin bed regeneration process in S6 comprises the following steps:

[0017] Step 1: Inject backwash water into the ion exchange column to backwash the resin bed for 15-20 minutes. The expansion rate of the resin bed is controlled at 40%-60%. The amount of backwash water is 4-6 times the volume of the resin bed.

[0018] Step 2: After backwashing, add regeneration agent HCL, the concentration of HCL is 15%, and the regeneration time is 1-2 hours to ensure that the regeneration agent is in full contact with the resin bed. After regeneration, slowly wash the resin bed with pure water to wash away the residual acid. The amount of pure water is 20-25 times the volume of the resin bed.

[0019] The present invention has the following advantages:

[0020] 1. The concentration of concentrated hydrochloric acid is 35%-38%, the oxidant is hydrogen peroxide, the mass ratio of concentrated hydrochloric acid to platinum-containing slag is 1:0.5-2.5, the mass ratio of hydrogen peroxide to platinum-containing slag is 1:0.1-0.2, the reaction time is 8-9 hours, concentrated hydrochloric acid and oxidant are used to dissolve platinum, filtered to obtain a platinum-containing liquid, and the platinum-containing liquid is injected into an ion exchange column equipped with a resin bed at a flow rate of 4-7BV / hour, and the acidity and chloride ion concentration of the solution can be adjusted according to the concentrated hydrochloric acid and oxidant, so as to optimize the adsorption effect of platinum metal on the resin bed;

[0021] 2. The platinum-containing solution is injected into an ion exchange column equipped with a resin bed at a flow rate of 4-7 BV / hour. The ion exchange resin is CH-97, adsorption time is 1-1.5 hours, adsorption humidity is 40%-50%, ensure the flow rate of platinum-containing liquid through the resin bed, make the platinum-containing liquid fully contact with the resin bed, adsorb the platinum ions in the solution through the resin bed, and achieve separation from impurities. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A flow chart of a method for recovering platinum metal based on an ion exchange process is provided for some embodiments of the present invention. DETAILED DESCRIPTION

[0023] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] like Figure 1 As shown, a method for recovering platinum metal based on an ion exchange process in an embodiment of the first aspect of the present invention comprises the following steps:

[0025] S1: adding 1.5-2.5 times of water to the platinum-containing waste liquid, stirring for 10-20 minutes, settling for 2-3 hours and filtering to obtain a filtrate and a filter residue, and calcining the filter residue at a constant temperature of 380-420° C. for 4-5 hours;

[0026] S2: After calcination, the filter residue is naturally cooled to room temperature, the cooled filter residue is ground into powder, the ground filter residue is screened through a sieve, and the filter residue with a particle size of 200-300 mesh is selected, and the powder is added to the filtrate in S1, and then dilute hydrochloric acid with a concentration of 10%-15% is added, and stirred at 35-60°C for 5-10 minutes, the solution Ph is controlled to be 6-8, and the solution is precipitated for 1-2 hours and filtered to obtain platinum-containing slag and dry it;

[0027] S3: adding 1.5-3 times of concentrated sulfuric acid to the dried platinum-containing slag to dissolve the platinum-containing slag with the concentrated sulfuric acid for 1.5-3 hours at a dissolution temperature of 90-130° C., controlling the Ph of the platinum-containing solution to be 2-11, and then adding concentrated hydrochloric acid and an oxidant to dissolve the platinum, stirring at the same time to ensure full contact, filtering, separating the unreacted solid residue from the platinum-containing solution, and obtaining the platinum-containing solution;

[0028] The concentration of concentrated hydrochloric acid is 35%-38%, the oxidant is hydrogen peroxide, the mass ratio of concentrated hydrochloric acid to platinum-containing slag is 1:0.5-2.5, the mass ratio of hydrogen peroxide to platinum-containing slag is 1:0.1-0.2, the reaction time is 8-9 hours, and the acidity and chloride ion concentration of the solution can be adjusted according to the concentrated hydrochloric acid and the oxidant, so as to optimize the adsorption effect of platinum metal on the resin bed;

[0029] S4: injecting the platinum-containing solution into an ion exchange column equipped with a resin bed at a flow rate of 4-7 BV / hour, and adsorbing the platinum ions in the solution through the resin bed to achieve separation from impurities. The adsorption time is 1-1.5 hours and the adsorption humidity is 40%-50%;

[0030] S5: After the resin bed is saturated with adsorption, an eluent with a concentration of 15%-20% is used, and the eluent is preheated to 20-55°C, and the adsorbed platinum group metal ions are replaced and eluted by the eluent to obtain a platinum-containing eluent;

[0031] S6: adding 25%-30% of a reducing agent sodium bisulfite solution to the platinum-containing eluent at 80-100°C for a reaction time of 0.8-1 hour. After the reaction is completed, cooling rapidly to room temperature, filtering to remove insoluble residues, collecting the filtrate, calcining at 680-700°C, controlling the calcination temperature at 700-800°C for 12-15 hours, so as to effectively remove low-boiling impurities and obtain preliminary platinum metal, and then pickling the preliminary platinum metal with dilute hydrochloric acid at a concentration of 10%-15% for 50-60 minutes; removing oxides and surface impurities that are difficult to remove, rinsing with pure water for 10-15 times after pickling to ensure that residual acidic substances and other soluble impurities are completely removed, and drying the washed platinum to obtain high-purity platinum metal, and then regenerating the resin bed in the ion exchange column;

[0032] The resin bed regeneration process includes the following steps:

[0033] Step 1: Inject backwash water into the ion exchange column to backwash the resin bed for 15-20 minutes. The expansion rate of the resin bed is controlled at 40%-60%. The amount of backwash water is 4-6 times the volume of the resin bed.

[0034] Step 2: After backwashing, add regeneration agent HCL, the concentration of HCL is 15%, the regeneration time is 1-2 hours, ensure that the regeneration agent is fully in contact with the resin bed, and after regeneration, slowly wash the resin bed with pure water to wash away the residual acid. The amount of pure water is 20-25 times the volume of the resin bed;

[0035] Example 1

[0036] A method for recovering platinum metal based on an ion exchange process comprises the following steps:

[0037] S1: adding 1.5-2.5 times of water to the platinum-containing waste liquid, stirring for 20 minutes, precipitating for 3 hours and filtering to obtain a filtrate and a filter residue, and calcining the filter residue at a constant temperature of 380-420° C. for 5 hours;

[0038] S2: Grind the calcined filter residue into powder to increase the contact area with the solution, which is helpful to improve the efficiency of subsequent dissolution and make platinum metal more easily react with the dissolving solution. Add the filtrate in S1 and then add 15% dilute hydrochloric acid, stir at 50°C for 8 minutes, repeat the above steps 5 times, wherein the total mass ratio of dilute hydrochloric acid to filtrate is 0.5:4, control the solution Ph to 6, precipitate for 2 hours and filter to obtain platinum-containing slag and dry it;

[0039] S3: adding 3 times concentrated sulfuric acid to the dried platinum-containing slag to dissolve the platinum-containing slag with the concentrated sulfuric acid for 3 hours at a dissolution temperature of 120° C., controlling the Ph of the platinum-containing solution to be 9, then adding concentrated hydrochloric acid and an oxidant to dissolve the platinum, filtering, and obtaining a platinum-containing solution;

[0040] The concentration of concentrated hydrochloric acid is 37%, the oxidant is hydrogen peroxide, the mass ratio of concentrated hydrochloric acid to platinum-containing slag is 1:2, the mass ratio of hydrogen peroxide to platinum-containing slag is 1:0.1, the reaction time is 9 hours, and the acidity and chloride ion concentration of the solution can be adjusted according to the concentrated hydrochloric acid and the oxidant, so as to optimize the adsorption effect of platinum metal on the resin bed;

[0041] S4: injecting the platinum-containing solution into an ion exchange column equipped with a resin bed at a flow rate of 7 BV / hour, and adsorbing the platinum ions in the solution through the resin bed to achieve separation from impurities. The adsorption time is 1.5 hours and the adsorption humidity is 50%;

[0042] S5: After the resin bed is saturated with adsorption, an eluent with a concentration of 20% is used, and the eluent is preheated to 55° C. The saturated resin bed is desorbed by the eluent, and the adsorbed platinum group metal ions are replaced and eluted to obtain a platinum-containing eluent;

[0043] S6: Add 30% of reducing agent sodium bisulfite solution to the platinum-containing eluent at 90°C for 1 hour. After the reaction is completed, cool it quickly to room temperature, filter to remove insoluble residue, collect the filtrate, and calcine it at 680-700°C. The calcination temperature is controlled at 800°C for 15 hours to effectively remove low-boiling impurities and obtain preliminary platinum metal. Then, pickle the preliminary platinum metal with dilute hydrochloric acid at a concentration of 10%-15% for 60 minutes; remove difficult-to-remove oxides and surface impurities, rinse with pure water 12 times after pickling to ensure that residual acidic substances and other soluble impurities are completely removed, and dry the washed platinum to obtain high-purity platinum metal, and then regenerate the resin bed in the ion exchange column.

[0044] It should be understood that these embodiments are only to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention.

Claims

1. A method for recovering platinum metal based on ion exchange process, characterized in that: The following steps are involved: S1: adding 1.5-2.5 times of water to the platinum-containing waste liquid, stirring for 10-20 minutes, settling for 2-3 hours and filtering to obtain a filtrate and a filter residue, and calcining the filter residue at a constant temperature of 380-420° C. for 4-5 hours; S2: After calcination, the filter residue is naturally cooled to room temperature, the cooled filter residue is ground into powder, the ground filter residue is screened through a sieve, and the filter residue with a particle size of 200-300 mesh is selected, and the powder is added to the filtrate in S1, and then dilute hydrochloric acid with a concentration of 10%-15% is added, and stirred at 35-60°C for 5-10 minutes, the solution Ph is controlled to be 6-8, and the solution is precipitated for 1-2 hours and filtered to obtain platinum-containing slag and dry it; S3: adding 1.5-3 times of concentrated sulfuric acid to the dried platinum-containing slag to dissolve the platinum-containing slag with the concentrated sulfuric acid for 1.5-3 hours at a dissolution temperature of 90-130° C., controlling the Ph of the platinum-containing solution to be 2-11, and then adding concentrated hydrochloric acid and an oxidant to dissolve the platinum, stirring at the same time to ensure full contact, filtering, separating the unreacted solid residue from the platinum-containing solution, and obtaining the platinum-containing solution; S4: Inject the platinum-containing solution into an ion exchange column equipped with a resin bed at a flow rate of 4-7 BV / hour. The ion exchange resin is CH-97, adsorption time is 1-1.5 hours, adsorption humidity is 40%-50%; S5: After the resin bed is saturated with adsorption, an eluent with a concentration of 15%-20% is used, and the eluent is preheated to 20-55°C, and the adsorbed platinum group metal ions are replaced and eluted by the eluent to obtain a platinum-containing eluent; S6: adding a reducing agent to the platinum-containing eluent at 80-100°C for a reaction time of 0.8-1 hour. After the reaction is completed, rapidly cooling to room temperature, filtering to remove insoluble residues, collecting the filtrate, calcining at 680-700°C, and then regenerating the resin bed in the ion exchange column.

2. The method for recovering platinum metal based on ion exchange process according to claim 1, characterized in that: The mass ratio of the total mass of the dilute hydrochloric acid to the mass of the filtrate is 0.5:3-5.

3. The method for recovering platinum metal based on ion exchange process according to claim 1, characterized in that: The concentration of the concentrated hydrochloric acid is 35%-38%, the oxidant is hydrogen peroxide, the mass ratio of concentrated hydrochloric acid to platinum-containing slag is 1:0.5-2.5, the mass ratio of hydrogen peroxide to platinum-containing slag is 1:0.1-0.2, and the reaction time is 8-9 hours.

4. The method for recovering platinum metal based on ion exchange process according to claim 1, characterized in that: The reducing agent is 25%-30% sodium bisulfite solution.

5. The method for recovering platinum metal based on ion exchange process according to claim 1, characterized in that: The resin bed regeneration process in S6 comprises the following steps: Step 1: Inject backwash water into the ion exchange column to backwash the resin bed for 15-20 minutes. The expansion rate of the resin bed is controlled at 40%-60%. The amount of backwash water is 4-6 times the volume of the resin bed. Step 2: After backwashing, add regeneration agent HCL, the concentration of HCL is 15%, and the regeneration time is 1-2 hours to ensure that the regeneration agent is in full contact with the resin bed. After regeneration, slowly wash the resin bed with pure water to wash away the residual acid. The amount of pure water is 20-25 times the volume of the resin bed.

6. The method for recovering platinum metal based on ion exchange process according to claim 1, characterized in that: In the S6, the calcination treatment temperature is controlled at 700-800°C for 12-15 hours to obtain preliminary platinum metal, which is then pickled with dilute hydrochloric acid at a concentration of 10%-15% for 50-60 minutes. After pickling, the preliminary platinum metal is rinsed with pure water for 10-15 times, and the washed platinum is dried to obtain high-purity platinum metal.

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