JP3479483B2 - Recovery method of high purity platinum - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering high-purity platinum, and more specifically, it separates Te from an aqueous solution containing Pt and Te , or Pt, Pd and Te, or Pd and Te. The present invention relates to a method for separating Te and recovering highly pure Pt.
In particular, the present invention is a nonferrous metal for the purpose of nonferrous smelting .
And then collect gold and silver.
After Pt was solvent-extracted in the step (hereinafter referred to as “gold-silver step”) , the back extract was treated with dimethylglyoxime (DMG) for Pd separation, if necessary, to improve the method of recovering high-purity platinum. Further, the present invention relates to a platinum recovery method in which Te is also effectively separated and the purity of Pd and Te is improved.

[0002]

2. Description of the Related Art Platinum obtained in the process of refined non-ferrous metal gold and silver contains impurities such as Te, Pd and Fe.
Some of the sponge platinums obtained from these cannot satisfy the Te quality standards of less than 50 Pppm.

As a method for separating Pt and Pd, there is a solvent extraction method using dialkylethane as an extractant.
It is proposed in Japanese Patent No. 3524. This publication shows the possibility of separating Pt and Pd by adjusting the concentration of hydrochloric acid and the extraction time, but usually these are extracted and recovered at the same time. Next, Japanese Patent Application Laid-Open No. 11-229052 proposes a method of extracting Pd from a nitric acid acidic solution containing Pt and Pd with a oxime solvent and then contacting it with an octylamine solvent to extract Pd. However, it requires two stages of extraction. further,
Allyl alcohol is added to a mixed hydrochloric acid acidic solution of Pt and Pd to reduce Pd to a metallic state, sodium hydroxide is added to the filtrate after filtration and washing to make it alkaline, and formic acid is added to heat the Pt to a metallic state. P consisting of reducing and filtering
A method for separating t and Pd is proposed in Japanese Patent Laid-Open No. 6-287654, but the process is complicated. In addition, JP-A-1
JP-A-1212778 proposes a method for purifying a gold electrolytic solution in which dimethylglyoxime is added to a Pd-containing gold electrolytic solution to form and precipitate a Pd complex to separate Pd. The present applicant has filed a patent application for a method in which Pt is extracted into tributyl phosphate (TBP) and then the solution after TBP back-extraction is subjected to Pd removal with dimethylglyoxime (Japanese Patent Application No. 11-278892, hereinafter referred to as “previous application”). Wish ").

[0004]

As described above, Te,
There is no method for efficiently and simply removing Te or both Te and Pd from a Pt aqueous solution containing impurities such as Pd to recover high-purity platinum. The present invention is
In particular, after Pt is solvent-extracted, the back extract is treated with dimethylglyoxime, if necessary, to separate Pd and improve the method for recovering high-purity platinum.
It is also an object of the present invention to provide a method for recovering platinum, which is separated to improve the purity of Te or Pd and Te.

[0005]

The present inventors have found that in the method of the prior application, the P between the TBP back extraction and the Pt crystallization step is
When we examined the optimum conditions for d and Pt removal, we found that TBP
Te in the liquid after back extraction is tetravalent T in the absence of an oxidizing agent.
It was e ⁴⁺ and was found to be mixed in the crystallized Pt.
Based on this finding, Te quality reduction according to the present invention is first
Is the high-purity platinum recovery method of the starting solution containing Pt and Te?
From Pt with tributyl phosphate (TBP)
After TBP back extraction, H2O2 was added to the solution, and
Add more than double the molar ratio, then adjust the pH to 6 or more
The Pt contained in the liquid after the TBP back extraction is chloroplatinic acid.
The method is characterized by crystallization as ammon.
Therefore, the second method for recovering high-purity platinum contains Pt and Te.
Tributy Pt from a starting solution having Pd and further containing Pd
After back-extraction of TBP extracted with luphosphate (TBP)
H2O2 was added to the solution at a molar ratio of 150 times or more with respect to Te.
Then, adjust the pH to 8 or higher, and add to this pH adjusted liquid.
Dimethylglyoxime was added to separate Pd, filtered
Crystallization of Pt as ammonium chloroplatinate from the obtained filtrate
It is characterized by

A preferred embodiment of the first and second inventions will be described with reference to the flow chart shown in FIG. The object to be treated is preferably treated in a pure gold and silver step, and Pt is extracted by TBP. Generally, Pt 3000 to 10000 mg / L, P
It is a solution after TBP extraction containing d10 to 500 mg / L and Te10 to 800 mg / L. Scrub this,
Back-extract H ₂ PtCl ₆ with water or hydrochloric acid solution. This chloroplatinic acid solution is generally Pt 5000-1000.
0 mg / L, Pd10 to 100 mg / L, Te100 to 2
Contains 000 mg / L. PH of this chloroplatinic acid solution
Is less than 1, and Te contained in the chloroplatinic acid solution is in the Te ⁴⁺ state. H ₂ O ₂ to oxidize Te ⁴⁺ to Te ⁶⁺ Is added. Here, the H ₂ O ₂ / Te molar ratio is 170 or more in the first invention and 150 or more in the second invention. From the viewpoint of handling, 20 ~
It is preferable to add it as a 40% H ₂ O ₂ aqueous solution. Then, sufficiently stir. Then, in the case of the second invention, Pd is separated by DMG by the same method as in the previous application. In this treatment, DMG (C ₄ N ₂ O ₂ H _8, number _of moles 116) is P
It is preferable to use 2 times or more of d. In the subsequent filtration, Pd is separated and HCl is added to the filtrate to adjust the hydrochloric acid concentration to 1
Set to about molar. Next, both the first invention and the second invention are 20
The following reaction is caused by adding about 0 g / L of NH ₄ Cl to crystallize platinum ammonium chloride. H ₂ PtCl ₆ + 2NH ₄ Cl = (NH ₄ ) ₂ PtCl ₆ + 2HCl Te ⁶⁺ is transferred to the filtrate by filtration after crystallization, so high-purity Pt with a Te concentration of less than 10 ppm is recovered. . Next, the experimental results in the laboratory will be described.

[0007]

[Examples] Chlorplatinic acid solution 1 (Pt97) obtained from the Pt extraction step by TBP in which gold and silver were recovered in the pure gold and silver step
00 mg / L, Pd74 mg / L, Te1550 mg /
L) 2 L and chloroplatinic acid solution 2 (Pt 9500 mg /
L, Pd 25 mg / L, Te632 mg / L) 3 L,
The pH was adjusted to 1 with 250 g / L-NaOH. This adjusted liquid was used as a test liquid. (1) Pretreatment 1 35% H ₂ O ₂ aqueous solution was added at a (H ₂ O ₂ / Te) molar ratio of 5
The mixture was added so as to be 7,115,150,170,310,334 and stirred for 6 hours, and subsequently neutralized to pH = 6 or 8. (2) Pretreatment 2 The test solution was neutralized to pH = 8 without adding 35% H ₂ O ₂ aqueous solution and without stirring for 6 hours. (3) DMG (DMG / D
Pd in the liquid before addition of MG) molar ratio = 0 (that is, Example of the first invention) or molar ratio = 1 (that is, Example of the second invention) and added for 1 hour, and then stirred for 5 hours. After roughly collecting with, it was filtered again with a 1 μ membrane filter. (4) Crystallization treatment Concentrated hydrochloric acid was added to adjust the filtrate after addition of DMG to 1M-HCl, and then NH ₄ Cl at a concentration of 200 g / L was prepared.
After adding the aqueous solution, the mixture was stirred for 1 hour for crystallization. The crystallization slurry was filtered through a 5C filter paper, and the filtration residue was 200
After washing with a g / L-NH ₄ Cl aqueous solution, the amount of the filtrate including the washing liquid was measured. The liquid concentration in each step and the quality of each component in the Pt crystallized product are shown in Table 1 and FIG.

[0008]

[Table 1]

As can be seen from Table 1 and FIG.
The _35% H _{2 O} 2 aqueous solution with or without the _{addition, H} 2 O
_{If the} molar ratio of ₂ / Te is 170 times or more, the Te quality in the Pt crystallized product becomes extremely low, less than 10 ppm. Further, the test liquid 2, H ₂ O ₂ / Te molar ratio = 170 and the test liquid 2, H ₂ O ₂ / Te molar ratio = 310 are all examples of the first invention, but these results are compared. Then the pH
It can be seen that the amount of H ₂ O ₂ added is smaller in the case of 6 than in the case of 8. Furthermore, if DMG is added and pH is set to 8 ,
Te quality is 10 ppm even if the H ₂ O ₂ / Te molar ratio is low
It can be seen that the Pd quality becomes lower than the above value and the Pd quality also deteriorates.

[0010]

As described above, according to the present invention, T
High-purity Pt having an extremely low e concentration can be obtained.

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of the present invention.

FIG. 2 is a summary of the results of Examples, showing that Te in a Pt crystallized product
H ₂ O ₂ added amount on the quality, which is a graph showing crystallization pH, the effect of DMG added. In the figure, black circles indicate pH = 6.
DMG = 0, a black square mark indicates pH = 8, DMG = 1, and a blank square mark indicates pH = 8, DMG = 0.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-60-21341 (JP, A) JP-A-60-86220 (JP, A) JP-A-9-241768 (JP, A) JP-A-10- 102156 (JP, A) JP 10-259430 (JP, A) JP 2000-119762 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C22B 1/00-61 / 00

Claims (4)

(57) [Claims] 1. From a starting solution containing Pt and Te to Pt
TB extracted with tributyl phosphate (TBP)
H2O2 in the solution after P back extraction is 170 times more than Te
And then adjust the pH to 6 or above.
Pt contained in the liquid after TBP back extraction was converted to ammonium chloroplatinate.
Recovery of high-purity platinum characterized by crystallization
Way . 2. Containing Pt and Te, and further containing Pd
From the starting solution to Pt tributyl phosphate (TB
H2O2 was added to Te after TBP back extraction extracted in P).
Add to the molar ratio of 150 times or more to raise the pH to 8 or more.
Adjust and adjust the pH of the solution with dimethylglyoxime.
A filtrate obtained by adding Pd to separate it and then filtering.
And Pt are crystallized as ammonium chloroplatinate.
Collection method of high-purity platinum to be collected . 3. The method for recovering high purity platinum according to claim 1, wherein the H ₂ O ₂ is added as a 20 to 40% aqueous solution. 4. The method for recovering high-purity platinum according to claim 1, wherein the starting solution is obtained in a process of purifying nonferrous metal.