JPH0533071A - Method for separating and refining rhodium from aqueous solution - Google Patents

Abstract

PURPOSE:To separate and refine Rh with high purity and high yield from an aq. soln. containing Rh and at least one element selected from Pd, Pt, Au, Bi, Te, Pb and Cu. CONSTITUTION:After the aq. soln. of Rh containing other impurity metals is adjusted to have radical hydrochloric acid concn. to >=1mol/l, this soln. is then made to flow through a resin tower packed with a chelate resin to adsorb noble metals. Rh, Pd, Pt, Au, Bi, and Pb in the soln. are adsorbed by the chelate resin, while the soln. is continuously made to flow so that most of the Pd, Pt, Au, and Bi adsorbed by the resin are replaced by Rh to increase the proportion of Rh to the adsorbed metals to the resin. Then a sulfuric acid soln. of >=1.0mol/l concn. at >25 deg.C is made to flow through the resin tower to dissolve and elute Rh from the resin tower. By this method for refining, the used chelate resin can be again used, and this method can be applied for a Rh-contg. soln. produced by a treating process of slime in the electrolysis of silver or the like.

Description

Detailed Description of the Invention

[0001]

The present invention relates to the use of a chelating resin for adsorbing a noble metal from a Rh-containing liquid in which various impurities coexist.
The present invention relates to a method for separating and purifying Rh.

[0002]

2. Description of the Related Art P, such as silver electrolytic slime,
As a method for recovering Rh from a solution containing various metal elements such as t, Pd, Rh, Au, Bi, Te, Pb, and Cu, conventionally, 1) formic acid was added to reduce Rh element to precipitate it. , Mainly Cu
Formic acid reduction method for the purpose of separation from elements, 2) a method of adding sodium nitrite to make the liquid neutral and precipitating elements other than Rh are known.

[0003]

However, in the method of 1) above, elements such as Cu, Au, Pt, and Pd are mixed in the precipitate of Rh when Rh is reduced and precipitated. Rh cannot be roughly separated unless the operation of reducing and precipitating is repeated many times.

On the other hand, in the method 2), when elements such as Cu and Pd are present at a high content in the mixed solution from which Rh is to be recovered, Rh is also coprecipitated together with the elements such as Cu and Pd. The yield is low, and many labor-intensive steps such as dissolution, solid-liquid separation, and solid movement are difficult, and it is difficult to automate or save labor.

Recently, various kinds of chelate resins for adsorbing noble metals are commercially available. However, these resins adsorb all platinum group metal elements such as Pt, Pd and Rh, Au elements, etc.
There is nothing that can be selectively adsorbed and separated.
Furthermore, there is no effective method to elute the adsorbed metal from these chelate resins, and the adsorbed metal must be recovered by baking the resin, so the purification separation of Rh is insufficient and the cost becomes high. Will end up.

[0006] Therefore, an object of the present invention is a method for separating and purifying Rh from a solution in which Rh is dissolved with other metals as described above, and to separate Rh in a high ratio and a high yield. And to provide an economically advantageous method.

[0007]

Means for Solving the Problems That is, the present invention is based on Pd,
A method of separating and purifying Rh from an aqueous solution containing at least one element selected from the group consisting of Pt, Au, Bi, Te, Pb and Cu, and Rh, comprising: (1) free hydrochloric acid concentration of the aqueous solution; Is adjusted to 1 mol / l or more and then passed through a first resin tower filled with a chelating resin for adsorbing a noble metal, whereby (1-a) first, Rh, Pd, Pt, Au in the aqueous solution is Bi
By adsorbing Pb and Pb to the chelate resin, (1-b), by substituting Rh for most of Pt, Pd, Au, and Bi adsorbed on the chelate resin by continuing to pass the aqueous solution. The ratio of Rh in the adsorbed metal on the chelate resin is increased, and Pt, Pd, Au and Bi, which are simultaneously eluted, are eluted from the first resin tower, and (1-c) the above sub-steps (1-a) and ( 1-
b) through the steps of eluting and separating Te and Cu which are not adsorbed to the chelate resin from the first resin tower; and (2) a temperature of 25 ° C. in the first resin tower that has passed through step (1).
Above, pass the sulfuric acid acidic aqueous solution with a concentration of 1.0 mol / l or more,
This provides a method of separating and purifying Rh, which comprises a step of eluting Rh from the first resin tower and eluting it.

The chelating resin for adsorbing the noble metal used in the step (1) is, for example, SUMICHELE MC-10 (trade name, manufactured by Sumitomo Chemical Co., Ltd.), SUMIKAION KA-890 (trade name, manufactured by Sumitomo Chemical Co., Ltd.), UNICEREX UR-. 3900 (trade name, manufactured by Unitika), Diaion (trade name, manufactured by Mitsubishi Petrochemical Co., Ltd.) and the like.

In this step, Te and Cu are basically not adsorbed, but other metals are adsorbed. P to be processed
An aqueous solution containing at least one of d, Pt, Au, Bi, Te, Pb and Cu as an impurity, and containing Rh has a free hydrochloric acid concentration of preferably 1 mol / l or more when treated by the method of the present invention, It is more preferably adjusted to 3 mol / l or more. If the concentration of free hydrochloric acid is too low, the adsorption rate of Rh on the chelate resin will be extremely low. The conditions for passing the acidic hydrochloric acid solution containing Rh and other metals through the first resin tower filled with the chelate resin are preferably such that SV is in the range of 1 to 5.

First stage of step (1) [sub-step (1-a)]
Then, metals other than Te and Cu are adsorbed by the chelate resin.
Te and Cu flow out of the first resin tower without being adsorbed. In the next step (sub-step (1-b)) of the step (1), Rh ions have relatively strong adsorptivity for the chelate resin as compared with other impurity elements under acidic conditions with hydrochloric acid, Once adsorbed on the chelating resin, Pt, Pd, Au and Bi among the metals are eluted and replaced with Rh. Since this substitution proceeds with the passage of liquid, the ratio of Rh in the adsorbed metal increases, while the eluted Pt, Pd, Au and Bi are eluted from the resin tower first and separated. Thus, the separation of Rh from Pt, Pd, Au and Bi proceeds.

However, when the sub-step (1-b) progresses and a certain period of time elapses, the adsorption rate of Rh starts to decrease and Rh starts to flow out from the lower part of the first resin tower. So as not to lose this Rh,
In order to recover, when performing this step (1), it is preferable that the lower end of the first resin tower is connected in series with the second resin tower filled with the chelating resin for adsorbing the noble metal. As a result, Rh eluted from the first resin tower from the first resin tower can be adsorbed to the second resin tower and recovered.

Step (2) In this step, a temperature of 25 ° C. or higher and a concentration of 1.
An aqueous solution of 0 mol / l sulfuric acid is passed. Process (1)
After passing through, the chelating resin of the first resin tower is adsorbed with Rh in a concentrated state. Rh is eluted from the first resin column by passing an acidic aqueous sulfuric acid solution. Thus, Rh
Are separated and purified.

The temperature of the acidic sulfuric acid solution used is 25 ° C.
Above, preferably above 30 ℃, sulfuric acid concentration 1.0 mol / l
It is above, and preferably 1.5 to 3.0 mol / l. Since Rh forms a complex ion with chlorine and is adsorbed on the chelate resin, a sulfuric acid acidic aqueous solution is suitable as an eluent. Temperature is 25
Rh is less likely to elute below ℃.

Before passing the aqueous sulfuric acid solution in the step (2), preferably, first, the temperature in the first resin column after the step (1) is set to 30 ° C. or higher, preferably 50 ° C.
The above water is passed through, whereby Pb is eluted from the first resin tower. After performing the appropriate steps, step (2) is performed. If such a step is added, Pb can be separated. If the temperature of the water passed in the above additional step is lower than 30 ° C., it is difficult to elute Pb.

[0015]

Example 1 (a) Chelate resin Sumichelate MC-10 (trade name, manufactured by Sumitomo Chemical Co., Ltd.) 1000 ml was added to a sulfuric acid aqueous solution 5 having a concentration of 1.5 mol / l.
What was dispersed in 1 was prepared. This resin has an inner diameter of 50 mm
Two pipes (hereinafter referred to as a resin tower) packed in a vinyl chloride pipe of φ and 700 mm in length were prepared. These were connected in series (hereinafter, at the time of liquid passage, the resin tower (A) on the solution inflow side is the first resin tower, and the resin tower (B) on the solution outflow side)
Is called the second resin tower). The Rh-containing solution (hereinafter referred to as the original solution) in which the free hydrochloric acid concentration generated in the silver electrolytic slime treatment step and having already undergone the solvent extraction treatment of Pd and Pt was adjusted to 6.0 mol / l in the connected resin tower ) Is the first resin tower (A)
The solution was passed from the top of the flask under the condition of SV = 1.0 for 48 hours. The metal concentration of the original solution was as shown in Table 1.

(B) Next, remaining in the first resin tower (A)
In order to extrude the Rh-containing solution, an aqueous solution of hydrochloric acid having a concentration of 6.0 mol / l was passed for 6 hours under the condition of SV = 1.0 and was combined with the above-mentioned outflowing liquid. In this way, the concentration of metal components contained in the entire liquid (hereinafter referred to as hydrochloric acid outflow liquid) flowing out from the second resin tower (B) was measured, and the results are shown in Table 1.

(C) Thereafter, the first resin tower (A) is replaced with the second resin tower.
Separated from (B), deionized water with a temperature of 50 ° C was placed in the first resin tower (A).
Pb in the first resin tower (A) after passing 20 hours under the condition of SV = 1.0
Was eluted. At this time, the metal components contained in the liquid flowing out from the first resin tower (A) (hereinafter referred to as pure water eluate) were measured and the results are shown in Table 1.

(D) Next, a sulfuric acid aqueous solution having a temperature of 40 ° C. and a concentration of 1.5 mol / l was used for 24 hours under the condition of SV = 1.0 for the first resin tower (A).
Rh was eluted. The metal concentration of the eluate (hereinafter referred to as sulfuric acid eluate) at this time was measured, and the results were as shown in Table 1.

In Table 1, the rhodium ratio is
The ratio of the amount of Rh contained in the solution: x and the amount of the total amount of other elements to the amount of Rh: y: x / y. The Rh recovery rate is represented by the following formula: Rh recovery rate = [(Rh amount in original solution-Rh amount in hydrochloric acid eluate-Rh amount in pure water eluate) / Rh amount in original solution] × 100 (In the formula, the Rh amount is the amount as metal Rh.).

[0020]

[Table 1]

As shown by the results in Table 1, the Rh ratio was 28.4% in the original solution, but increased to 85.6% in the sulfuric acid eluate. The Rh recovery rate was 94.0%.

Example 2 Resin tower (A) used as the first resin tower used in Example 1
Was attached to the back of the resin tower (B) used as the second resin tower in Example 1 and replaced. In the same manner as in Example 1, the original liquid was passed through this connected resin tower for 30 hours under the condition of SV = 1.0.

After completion of the above-mentioned passage, in order to push out the original solution remaining in the first resin tower (B), a hydrochloric acid solution having a concentration of 6.0 mol / l was passed at SV = 1.0 for 6 hours, A hydrochloric acid eluate was obtained. Then, the first resin tower (B) was separated from the second resin tower (A), and pure water at a temperature of 50 ° C. was passed through the first resin tower (B) under the condition of SV = 1.0 for 15 hours. Furthermore, the temperature is 40 ° C and the concentration is 1.5 mo.
When 1 / l sulfuric acid was passed through the second resin column (A) at SV = 1.0 for 24 hours, a sulfuric acid eluate containing the eluted Rh was obtained. The concentrations of metals contained in the obtained hydrochloric acid eluate, pure eluate and sulfuric acid eluate were measured, and the results shown in Table 2 were obtained.

[0024]

[Table 2]

As shown in Table 2, the Rh ratio is
It was 28.4%, but it increased to 86.6% in the sulfuric acid eluate.
The Rh recovery rate was as high as 89.6%.

[0026]

INDUSTRIAL APPLICABILITY According to the method for separating Rh of the present invention, Rh can be separated from other impure metals at a high rate and a high yield, and the content of impurities in the recovered Rh is small. The chelating resin used can be reused repeatedly, which is economically advantageous. The method of the present invention is also suitable for labor saving and automation by a machine. This method, for example,
It is useful for separating and purifying Rh from a solution containing Rh and other various metals generated by the step of silver electrolytic slime treatment.

Claims (7)

[Claims] 1. A method for separating and purifying Rh from an aqueous solution containing Rh and at least one element selected from the group consisting of Pd, Pt, Au, Bi, Te, Pb and Cu, comprising: (1) After adjusting the concentration of free hydrochloric acid to 1 mol / l or more, the aqueous solution is passed through a first resin tower filled with a chelating resin for adsorbing a noble metal, whereby (1-a) first, Rh in the aqueous solution is , Pd, Pt, Au, Bi and
Pb is adsorbed on the chelate resin, (1-b) Next, by continuing the passage of the aqueous solution, most of Pt, Pd, Au and Bi adsorbed on the chelate resin are adsorbed.
By substituting with Rh, the ratio of Rh in the adsorbed metal on the chelate resin was increased, and Pt, Pd, Au and Bi that coeluted were simultaneously eluted.
Is eluted from the first resin tower, and (1-c) Te and Cu, which are not adsorbed on the chelate resin, are eluted from the first resin tower through the above sub-steps (1-a) and (1-b). A step consisting of separating; and (2) a temperature of 25 ° C. or higher in the first resin tower which has passed through step (1), a concentration
Having a step of passing 1.0 mol / l or more acidic aqueous sulfuric acid solution, and thereby eluting Rh from the first resin tower.
Rh separation and purification method. 2. The method according to claim 1, wherein the step (1)
In the method, the concentration of free hydrochloric acid in the aqueous solution is adjusted to 3 mol / l. 3. The method according to claim 1, wherein the step (2)
The concentration of the acidic aqueous sulfuric acid solution used in is 1.5 to 3.0 mol / l
How to be. 4. The method according to claim 1, wherein the step (2)
The method in which the temperature of the acidic aqueous sulfuric acid solution used in is 30 ° C or higher. 5. The method according to claim 1, wherein the step (1)
Before passing the sulfuric acid acidic aqueous solution in the step (2) into the first resin tower that has passed through, first pass water having a temperature of 30 ° C. or higher, thereby eluting Pb from the first resin tower. The method of carrying out step (2) after carrying out step. 6. The method according to claim 5, wherein the temperature of water passed through before the step (2) is 50 ° C. or higher. 7. The method of claim 1, wherein the steps
(1) is performed in a state where the lower end of the first resin tower is connected in series with a second resin tower filled with a chelating resin for adsorbing a noble metal, whereby the step (1) is performed from the first resin tower. A method in which the eluted Rh is adsorbed on the second resin tower and collected.