JPH09324224A - Method of recovery of platinum group element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique of recovery of respective platinum group elements from an alloy containing platinum group elements with high efficiency by reducing a material containing the oxides and sulfides of platinum group elements and providing the resultant alloy, containing platinum group elements, with high crushability. SOLUTION: A reducing agent and Fe3 P are added to a material containing at least either of the oxides and sulfides of platinum group elements, which is melted in an inert atmosphere of argon, nitrogen, etc., at 800-1200 deg.C reduction temp. and 1450-1650 deg.C melting temp. Subsequently, cooling is carried out while regulating the average cooling rate, until 300 deg.C is reached, to >=1 deg.C/sec, and the resultant alloy, containing platinum group elements, is crushed to <=75μm. The resultant alloy powder is leached with hydrochloric acid and chlorine gas, and the platinum group elements are recovered in a leach liquor.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method of recovering a platinum group element from a substance containing a platinum group oxide or a platinum group sulfide.

[0002]

2. Description of the Related Art When recovering a platinum group element from a substance containing a platinum group oxide and a platinum group sulfide, it is difficult to leach the platinum group oxide as it is by a wet method. Therefore, it is necessary to reduce the platinum group oxide once. When this is directly reduced and melted by a dry method to obtain a platinum group alloy,
The grindability of this alloy is extremely poor. If the alloy has poor pulverizability, the leaching rate in the wet process of leaching the platinum group is lower than that of the pulverized alloy, and further leaching takes a long time.

Therefore, when recovering the platinum group from a platinum group catalyst or the like, these are reduced and melted with a metal such as copper or iron to form a platinum group-containing alloy, and the obtained alloy is melted,
Recover from the resulting lysate. In this method, although the pulverizability is improved, it is still poor, and since a relatively large amount of copper or iron is added to the trace amount of platinum group element to be recovered, the amount of material to be dissolved in the wet process As a result, the actual yield of platinum group becomes low, which is economically disadvantageous.

Although the platinum group is alloyed in the same manner as above, the obtained alloy is dissolved by oxidative leaching or electrical anodic oxidation, and the platinum group is once concentrated as a residue or slime. A method of processing and collecting is also known. In this method, when anodizing an alloy,
Since the current that can be passed is limited, the processing speed is slow and large equipment is required. In addition, since it takes a long time to recover, it is forced to have a large amount of expensive platinum group metalwork. Therefore, this method is not economically advantageous.

[0005]

The present invention has been made in view of the above situation, and a platinum group-containing alloy obtained by reducing a substance containing a platinum group oxide and a sulfide has high pulverizability. An object of the present invention is to provide a technique for recovering each platinum group element more efficiently than an alloy containing a platinum group.

[0006]

According to the method of the present invention for solving the above problems, a reducing agent and Fe ₃ P are added to a substance containing an oxide and a sulfide of the platinum group, and then an inert gas such as argon or nitrogen is added. In the atmosphere, the reduction temperature is set to 800 ° C to 120 ° C.
Platinum group-containing alloy obtained by melting at 0 ° C., melting temperature of 1450 ° C. to 1650 ° C., and then cooling at an average cooling rate of up to 300 ° C. at a cooling rate of 1 ° C./second or more is pulverized to 75 μm or less and alloyed. Use as powder. Then, the obtained alloy powder is leached with hydrochloric acid and chlorine gas to recover the platinum group element in the leachate.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION When leaching with hydrochloric acid and chlorine gas in a wet treatment process, the particle size of alloy powder has a great influence on the leaching rate and the leaching rate. Therefore, the pulverizability of the platinum group-containing alloy is extremely important.

As a result of various investigations, the present inventors have noticed that rapid cooling suppresses the growth of alloy particles, improves the pulverizability of the alloy, and the pulverizability of the alloy containing P is high. It was found that the pulverizability can be improved by adjusting the P concentration in the platinum group alloy.

In the method of the present invention, the grade of P in the alloy is preferably 1 to 20% by weight, and more preferably 5 to 10%.

The source of P in the alloy is not particularly limited, but Fe ₃ P is the easiest to handle, simple, and reliable.

The method of the present invention will be described below with reference to examples and comparative examples.

The reducing agent added in the method of the present invention contains carbon, and it is preferable that the amount of carbon be C: O = 1: 2 or more in molar ratio with respect to the amount of oxygen in the raw material.

[0013]

【Example】

(Example 1) Pt as a platinum group element is 8.0%, Pd is 6.4%, Rh is 5.2%, Ir is 3.7%, Os is 0.4%, and Ru is 7.4%. , Au of 0.73%, other elements of Fe of 19.3%, Cu of 8.06%, N
100 g of a white metal catalyst residue containing oxides and sulfides containing 5.31% of i, 5.32% of S, and the like, 21.6 g of coke as a reducing agent, and F having a P quality of 15.6 wt%.
66.7 g of e ₃ P was placed in an alumina crucible, heated to 900 ° C. in Ar and kept at 900 ° C. for 1 hour for reduction melting.

Thereafter, the temperature is raised to 1550 ° C. and 1550
The reduced metal was completely melted by holding at 2 ° C. for 2 hours, settled, and then the alumina crucible was taken out from the furnace and rapidly cooled in the atmosphere. At this time, the average cooling rate from 1550 ° C to 300 ° C was 1.2 ° C / sec.

The obtained metal and dust were 158.5 g (P grade in the alloy: 7.1%). As a result of observing this metal and dust with EPMA, no platinum group oxide was observed, and P and each platinum group were observed in the structure in the metal, and the structure was refined.

[0016] These metals and debris were crushed for 60 seconds by a vibration mill crusher, and sieved using a sieve having a mesh size of 75 microns. No sample remained on the sieve and the total amount was 75
It was possible to crush it to less than a micron. The pulverized product having a particle size of 75 microns or less is hydrochloric acid concentration 5N, slurry concentration 400 g /
After leaching by blowing chlorine gas at a liquid temperature of 90 ° C. in a liter and increasing the ORP to the maximum value, 2% of HNO ₃ was added.
Added and held for 6 hours. Then, the slurry was filtered to obtain a filtrate (leaching solution A), a washing solution (washing solution B), and a residual residue (washing residue C) again. The leaching rate of each metal from the analysis value of each liquid and the residue is expressed by the formula of leaching rate = (A + B) × 100 / (A + B + C), Pt is 99.8%, Pd is 99.9%,
Rh is 99.5%, Ir is 99.1%, and Ru is 99.4.
%, Au was 98.5%, and a high leaching rate was obtained.

(Example 2) Metals and scraps were obtained in the same manner as in Example 1 except that the melt at 1550 ° C was quenched with water.

The total amount of the obtained metal and dust was 159.
It was 0 g. As a result of observing the metal and the dust with EPMA, no platinum group oxide was found in any of them and the metal structure was refined.

Both the metal and the dust were crushed for 60 seconds by a vibrating mill and sieving was performed using a sieve having an opening of 75 microns, and there was no metal left on the sieve, and the total amount was 75 microns or less. I was able to crush it.

The pulverized product having a particle size of 75 microns or less was used in Example 1.
The same treatment as described above was carried out to obtain a filtrate, a washing solution and a residue. And
The noble metal was analyzed in the same manner as in Example 1, and the leaching rate of each metal was obtained from the analysis value obtained. As a result, Pt is 99.5%,
99.6% for Pd, 99.1% for Rh, 9 for Ir
High leaching rates of 8.7%, 98.6% for Ru, and 98.0% for Au could be obtained.

Example 3 A metal and a scrap were obtained in the same manner as in Example 2 except that the average cooling rate from 1550 ° C. to 300 ° C. was set to 1 ° C./sec. Similarly, the leaching rate was obtained. As a result, the same leaching rate as in Example 1 was obtained.

It should be noted that the total amount of 7 by crushing with a vibration mill for 60 seconds.
It could be crushed to less than 5 microns.

(Example 4) The amount of Fe ₃ P added at 15.6 wt% was adjusted to 5.5 so that the P quality in the alloy would be 1.0%.
A metal and a residue were obtained in the same manner as in Example 1 except that the value was g, and this was crushed, and the leaching rate was obtained in the same manner as in Example 1. As a result, in each case, the same leaching rate as in Example 1 was obtained.

It should be noted that the total amount of 7 by crushing with a vibration mill for 60 seconds.
It could be crushed to less than 5 microns.

(Example 5) P grade in the alloy is 20 wt%
A metal and a residue were obtained in the same manner as in Example 1 except that P was added so that the leaching rate was obtained in the same manner as in Example 1. As a result, in each case, the same leaching rate as in Example 1 was obtained.

It should be noted that the total amount of 7 by crushing with a vibration mill for 60 seconds.
It could be crushed to less than 5 microns.

(Comparative Example 1) A metal and a scrap were obtained in the same manner as in Example 1 except that the material was kept at 1550 ° C for 2 hours and then cooled in the furnace. The obtained metal and dust were 158.7 g. As a result of observing this metal and dust with EPMA,
No platinum group oxide was found, but the metal structure was coarse. The average cooling rate from 1550 ° C to 300 ° C was 0.4 ° C / sec.

These metals and scraps were crushed by a vibration mill crusher, but this metal was an extremely hard alloy that was difficult to cut and crush, and a leaching test could not be performed.

(Comparative Example 2) A test by matting was carried out as a method for improving the pulverizability. P as a platinum group element
t is 8.0%, Pd is 6.4%, Rh is 5.2%, Ir
Is 3.7%, Os is 0.4%, Ru is 7.4%, Au is 0.73%, and Fe is 19.3% and C as other elements.
150 g of a residue containing oxides and sulfides containing 8.06% of u, 5.31% of Ni, 5.42% of S, etc. was placed in an alumina crucible and heated to 1200 ° C. in Ar to reduce the agent. After 32.5 g of coke was added to reduce the platinum group oxide for 1 hour, 80 g of sulfur was added to the mixture for 3 hours for matting.
It was added in portions. After the addition of sulfur, it was held for 2 hours and then cooled in the furnace. The obtained mat had a weight of 143.7 g and a residue of 18.3 g.

These metals and debris were crushed by a vibration mill crusher for 60 seconds and sieved using a sieve having a mesh size of 75 microns. The sample that passed through the sieve was 159.4 g and was 9
8.4% could be ground to less than 75 microns. This pulverized product of 75 microns or less is added with hydrochloric acid concentration of 5N and slurry concentration of 40
Chlorine gas was blown in at a liquid temperature of 90 ° C. at 0 g / liter to perform leaching. After the ORP increased to the maximum value, 2% of HNO ₃ was added and the mixture was kept for 6 hours. The leaching solution was filtered to obtain a filtrate (leaching solution A), a washing solution obtained by washing the residue with water (washing solution B), and a residue remaining again (washing residue C). The leaching rate of each metal from the analysis values of each liquid and residue is expressed by the formula of leaching rate = (A + B) × 100 / (A + B + C), Pt is 92.8%, Pd is 99.3%,
Rh is 98.4%, Ir is 53.3%, and Ru is 59.8.
%, Au was 95.0%, and the leaching rate of Ir and Ru was poor.

[0031]

According to the method of the present invention, it is possible to obtain a platinum group-containing alloy having extremely excellent pulverizability. For this reason, leaching in the platinum group recovery step becomes easy, and a high leaching rate can be obtained in the wet treatment step.

Claims (5)

[Claims] 1. A substance containing at least one of a platinum group oxide and a platinum group sulfide and a reducing agent are mixed and reduced and melted to obtain an alloy, and the alloy is crushed to obtain an alloy powder. A method for recovering a platinum group element by wet-treating a metal powder, which comprises adding a reducing agent and Fe ₃ P, reducing and dissolving, and then rapidly cooling to obtain an alloy. 2. The average cooling rate up to 300 ° C. is 1 ° C. /
The cooling is performed at a cooling rate of 2 seconds or more.
The described method. 3. The method according to claim 1, wherein the P grade in the obtained alloy is 1 to 20% by weight. 4. After adding a reducing agent to a substance containing a platinum group oxide and a sulfide, it is reduced at 800 ° C. to 1200 ° C. in an inert atmosphere such as argon or nitrogen, and then at 1450 ° C. to 1650 ° C. Completely dissolved, then 30
The method according to claim 3, wherein the average cooling rate up to 0 ° C is cooled at a cooling rate of 1 ° C / sec or more. 5. A substance containing a platinum group oxide and a sulfide and a reducing agent and Fe ₃ P in an alloy having a P grade of 1 to 20.
After adding so as to make the weight%, reduction is performed at 800 ° C. to 1200 ° C. in an inert atmosphere such as argon and nitrogen, and then completely dissolved at 1450 ° C. to 1650 ° C., then 3
The platinum group-containing alloy obtained by cooling the average cooling rate up to 00 ° C at a cooling rate of 1 ° C / sec or more is crushed to 75 microns or less to obtain an alloy powder, and the obtained alloy powder is leached with hydrochloric acid and chlorine gas. A method for recovering a platinum group element, comprising recovering a platinum group element in the leachate.