JP2861434B2 - Method for recovering In from Pb-In-Ag alloy - 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 separating and concentrating In from an In-containing raw material containing Pb and Ag as main impurities.

[0002]

2. Description of the Related Art Conventionally, a Pb-Sn alloy has been used as an insoluble anode for wet Zn plating by electroplating. However, since a Pb-In-Ag alloy has a higher plating efficiency than a Pb-Sn alloy, Alternatives to Pb-In-Ag alloys are in progress as insoluble anodes. Pb
-Since the In used in the In-Ag alloy is expensive, it is necessary to effectively use the Pb-In-Ag alloy scrap. However, this alloy scrap contains many impurities, and is dissolved again. Simply adjusting the components of In and Ag does not satisfy the specifications as an insoluble anode. For this reason, it has become important to recover In from Pb-In-Ag alloy scrap by some means.

Conventionally, as a method for recovering In from an In-containing raw material, for example, the following three methods have been proposed. As a first method, an In-containing raw material is dissolved in a sulfuric acid aqueous solution, and the resulting In-containing aqueous solution is
Neutralize with an alkali hydroxide such as OH to precipitate In and separate it from the aqueous solution. Next, this precipitate was redissolved with an aqueous sulfuric acid solution to obtain an aqueous solution of In. Then, a powder such as Zn powder was added as a reducing agent to this, and the crude I was subjected to cementation.
There is a way to get n. In the second method, after dissolving an In-containing raw material with sulfuric acid, a sulfide is added to an aqueous solution to perform a sulfidation treatment, and the generated sulfide is filtered off. In is contained in the aqueous solution because it is unlikely to form a sulfide precipitate. The separated aqueous solution is neutralized by adding an alkali hydroxide, and the formed precipitate is separated. Then, the precipitate is dissolved in an aqueous hydrochloric acid solution, and a sulfide is added thereto again to perform a sulfidation treatment. After adjusting the pH of the aqueous solution obtained by filtering the obtained sulfide, crude In is obtained by a cementation method in the same manner as in the first method. In the third method, an In-containing raw material is put into a Pb blast furnace and taken out as a Pb-In alloy, which is dry-melted to be separated into dross and Pb metal containing Ag. Then, In is concentrated in the dross, the dross is reduced in an electric furnace, Pb containing In is electrolyzed by the Betts method, and In is concentrated and separated in the anode slime.

[0004]

However, all of these recovery methods are complicated in operation, and in addition, Pb-I
There is a disadvantage that it is unsuitable for treating a raw material having a low In grade such as n-Ag alloy scrap.

[0005] In view of the above problems, the present invention provides a Pb-In which can easily recover high-purity In from an In-containing material such as a Pb-In-Ag alloy scrap having a relatively low In content. An object of the present invention is to provide a method for recovering In from an Ag alloy.

[0006]

According to the present invention, a Pb-In according to the present invention is provided.
The method of recovering In from an Ag alloy is an alloy in which In is 5 to 30% by weight, Ag is 1 to 5% by weight, and the balance is substantially Pb, and In is 15% by weight or more and the balance is substantially Pb. And a composition comprising NH ₄ Cl at a temperature of 400 to 500 ° C. such that the weight ratio of In to the composition in the alloy is 10: 1 to 4 and thereby forming By separating the dross from the metal,
In is collected.

Here, the Pb-In-Ag alloy scrap has a composition in which In is 5 to 30% by weight, Ag is 1 to 5% by weight, and the balance is substantially Pb. The composition used in the present invention is Pb-In-Ag
The metal content obtained after contacting the alloy scrap material or the method of the present invention is contacted with NH ₄ Cl, allowed migrate In this material or metal component in in NH ₄ Cl, the NH ₄
It is obtained by separating Cl from a raw material or a metal component.

If the content of In contained in the above composition is less than 15% by weight, it is difficult to increase the concentration of In in dross obtained after the contact to a concentration at which it can be efficiently recovered (preferably at least 35% by weight). is there. The higher the concentration of In in the dross, the more desirable. However, in reality, when the In in the dross reaches about 70% by weight, it is not easy to further increase the concentration. Also, the amount of the composition depends on the I
If the amount is less than 100 g with respect to n1 kg, the distribution ratio of In in the alloy to dross and metal becomes constant, so that it is difficult to sufficiently transfer In into the dross. On the other hand, 400
When the amount exceeds g, the dross obtained after the contact is too lean, so that the subsequent recovery efficiency of the indium is reduced.

The reason why the contact is carried out at a temperature of 400 to 500 ° C. is that if the temperature is lower than 400 ° C., the fluidity of the molten alloy is not sufficient, so that the contact and the reaction with the composition are not carried out sufficiently. On the other hand, when the temperature exceeds 500 ° C., the separability of dross from the metal content thereafter decreases.

[0010]

According to the present invention, 5 to 30% by weight of In, Ag
An alloy consisting of 1 to 5% by weight with the balance substantially consisting of Pb;
In with 15% by weight or more of In and the balance substantially consisting of Pb and NH ₄
Cl is mixed with In in this alloy so that the weight ratio of In to the composition becomes 10: 1 to 4;
Contact is made at a temperature of ℃ 500 ° C. to transfer In in the alloy into the composition. This shift is presumed to be due to a reaction of In + NH ₄ Cl → NH ₃ + InCln (In has monovalent and trivalent). After addition of the composition, it is desirable to stir to promote contact and reaction. The dross thus obtained is filtered after dissolving with hydrochloric acid, and Zn powder is added thereto to obtain a sponge-like crude In by cementation. Then, the crude In is dissolved to form an anode, which is then subjected to a known general method such as electrolytic purification.
High-purity In of 9.99% or more can be recovered.

[0011]

Embodiments of the present invention will be described below in detail. 7.5% by weight of In and 1.2% by weight of Ag,
A Pb-In-Ag alloy scrap whose balance substantially consists of Pb is used as a raw material alloy. And 10kg of this raw material alloy
In a graphite crucible in an electric furnace at a temperature of 460 ° C.
2 kg of ammonium chloride NH ₄ Cl are added. After about 1.5 hours, the dross on the surface was scooped. The dross thus obtained was designated as dross 1, and its physical quantity and analytical values are shown in the table of FIG. This dross 1 corresponds to the above-described composition, contains 18.8% by weight of In, and the balance substantially consists of Pb and NH ₄ Cl.

Next, the raw material alloy 10 having the same composition as that described above is used.
kg was melted in a graphite crucible in an electric furnace at a temperature of 460 ° C., and 200 g of the above-mentioned dross 1 was added. After about 1.5 hours, dross on the surface was scooped. The dross thus obtained is referred to as dross 2. In addition, a metal component (metal) was obtained in addition to dross 2. The physical quantity and analytical values of the dross 2 and the metal content are also shown in the table of FIG.

As is clear from the table, In the dross 2 finally obtained, In is concentrated by 50% by weight or more.
This dross 2 was filtered after dissolving hydrochloric acid as described above,
The powder was added and sponge-like crude I was formed by cementation.
n and then dissolve the crude In to form an anode, and easily purify the high-purity In by a known general method such as electrolytic purification.
Can be obtained.

[0014]

As described above, the Pb-In according to the present invention is used.
According to the method for recovering In from Ag-Ag alloy, Pb-In-Ag alloy scrap having relatively low In content such as In
In can be easily separated and concentrated from the contained raw material alloy, and expensive In can be efficiently recovered.

[Brief description of the drawings]

FIG. 1 is a table showing the dross 1 and dross 2 and the weight of metal (metal) and the analysis values of Pb, In, and Ag according to an embodiment of the present invention.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C22B 58/00

Claims (1)

(57) [Claims] 1. An alloy comprising 5 to 30% by weight of In, 1 to 5% by weight of Ag and the balance substantially consisting of Pb.
% By weight or more of the composition substantially consisting of Pb and NH ₄ Cl, with the weight ratio of In to the composition being 10: 1 to 4 in the alloy and being 400 to 500.
Pb-In-Ag in which the contact is made at a temperature of 0 ° C. and the dross formed is separated to recover In.
Method for recovering In from alloy.