JPS5824377B2 - Method for separating and removing arsenic from indium-containing materials where arsenic coexists - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating and removing arsenic coexisting therein from an indium-containing material such as lead slag.

Originally, indium does not exist in regular ores, but is contained in trace amounts in zinc ores, and is recovered from lead slag produced when recovering cadmium, for example.

Therefore, since metals such as arsenic, lead, zinc, cadmium, tellurium, etc. coexist in indium raw materials, techniques for separating and removing these metals become a problem when recovering indium.

In particular, it is desired to provide an effective technique for removing arsenic.

In view of the above-mentioned current situation, an object of the present invention is to provide a method for effectively separating and removing arsenic coexisting in an indium-containing material in a method of recovering indium from an indium-containing material (raw material) by sulfuric acid leaching method. shall be.

The present invention will be explained in detail below.

Here, we will mainly explain the case where lead slag, which is a by-product during the smelting of cadmium, is used as the indium-containing material.

An example of the composition of the lead slag is shown in Table 1 below.

In the present invention, first, the lead slag is leached with a sulfuric acid solution to leaching out the indium.

In addition to indium, this leachate also contains arsenic, cadmium, zinc, thallium, and a small amount of lead.

Then, after separating the leachate from the residue, SO,...
When treated with an alkali, such as caustic soda, in the presence of a reducing agent to a pH of 3 to 4, indium precipitates, and most of the other coexisting metals remain in the liquid.

Therefore, by fractionating the precipitate, a solid content with a high indium distribution ratio can be obtained.

However, arsenic and thallium and substituted cadmium, zinc and lead remain in the solid content.

Next, in the present invention, the solid content is treated with an alkali such as caustic soda in the presence of hydrogen peroxide to adjust the pH to 13 or higher, thereby eluting most of the arsenic remaining in the solid content in the form of NaAsO3.

Therefore, if the liquid component is separated and removed from this alkali-treated product, an indium-containing mud with an extremely low arsenic content relative to indium can be obtained.

Next, the liquid component was separated from the alkali-treated product.

An example of the composition of the indium-containing mud (solid content) is shown in Table 2 below.

The indium-containing mud obtained by removing most of the arsenic as described above is dissolved in sulfuric acid with stirring.

Since the purpose of this dissolution treatment is to elute indium, the sulfuric acid concentration and pulp concentration during leaching are selected to be suitable for increasing the indium elution rate.

According to the inventor's experimental results, in order to reduce the loss of indium to the elution residue to 1 factor or less, the pulp concentration must be 100%.
In the case of g/l, the sulfuric acid concentration is preferably 50 g/l or more.

By this dissolution treatment with sulfuric acid, 80% or more of Bi and Pb remaining in the indium-containing mud can be separated.

Next, the eluate obtained as described above is sulfurized to remove arsenic and Tl remaining in the eluate.

Remove Cd.

This sulfiding treatment is carried out by introducing hydrogen sulfide, acidic sodium sulfide, etc. into the eluate, but care should be taken in this case since the sulfuric acid concentration of the eluate will affect the removal of the impure metals.

That is, if the sulfuric acid concentration of the eluate is low, during the sulfurization treatment, indium of 50 parts or more will be transferred to the solid content together with impure metals and will be lost, so it is preferable to set the sulfuric acid concentration to 1009/1 or more.

In addition, in order to effectively separate and remove impure metals by this sulfurization treatment, it is desirable to reduce the arsenic content in the eluate, and for this purpose, it is necessary to remove as much arsenic as possible by the alkali treatment described above. Is required.

The sulfurized product as described above was separated into solid and liquid using a solid-liquid separation means such as a filter press, and the resulting liquid, that is, the sulfurized liquid, was collected and neutralized with an alkali. Thereafter, it is dissolved in hydrochloric acid, followed by substitution using a conventional method to obtain sponge indium, which is treated with caustic soda and then electrolytically purified.

As described above, according to the present invention, in the method of recovering indium from an indium-containing material, arsenic coexisting in a relatively large amount in the material can be effectively separated and removed along with other impurity metals.

Next, the present invention will be explained in more detail by way of examples.

Lead slag having the composition shown in Table 1 above was used as an indium-containing raw material.

114 tons of lead slag was stored in the leaching tank, and 200 g
Supplying sulfuric acid with a concentration of 3009/l
! Leaching was carried out for 2 hours at a stirring speed of 600 R, P, M.

The leached product is solid-liquid separated using a filter press and the leached solution is recovered.

This leachate is transferred to a reduction tank, 802 is blown into it and caustic soda is added to adjust the pH of the liquid to 3 to 4, followed by solid-liquid separation using a filter press to recover precipitated solids.

This solid content is transferred to an alkali treatment tank, and 212 kg of hydrogen peroxide and a caustic soda aqueous solution having a concentration of 500 g/l are added thereto to adjust the pH to 13.5.

This alkali-treated product is subjected to solid-liquid separation using a filter press to recover precipitated solids (alkali-treated mud).

The composition of the solid content obtained was as shown in Table 3 below.

(Note) The amounts in the table indicate the values for alkali-treated mud 1100k17A.

Further, the composition of the treatment liquid obtained by fractionating the alkali-treated product was as shown in Table 4 below.

As is clear from Tables 3 and 4 above, most of the arsenic present in the indium-containing material can be separated and removed by the alkali treatment.

Next, transfer the alkali-treated mud (solid content) to a dissolution tank,
To this, sulfuric acid with a concentration of 2009/l was added to the alkaline treated mud 1.
Add 600R at a rate of about 12m3 per 1t to make the pulp density about 1009/l.

The dissolution treatment was carried out for 2 hours while stirring at speeds of P and M.

This dissolved material was subjected to solid-liquid separation using a filter press to remove dissolved residues.

(At this time, 177 I' of washing water was used in the filter press.

) The composition of the resulting solution is shown in Table 5 below.

Further, the results of analyzing the composition of the dissolved residue are shown in Table 6 below.

It is understood from Tables 5 and 6 above that the loss of indium to the dissolved residue due to the dissolution treatment with sulfuric acid is small, while the remaining lead and arsenic are separated.

The sulfuric acid solution obtained as described above was transferred to a sulfurization tank.
To this, add acidic sodium sulfide to 13 m° of the sulfuric acid solution.
It is added at a rate of 20 yu to perform sulfurization treatment.

In addition, the sulfuric acid concentration of the above-mentioned solution during this sulfurization treatment was set to 100
It was maintained at 9/l.

Further, the sulfiding treatment was carried out at room temperature for 2 hours while stirring.

Since a sulfide precipitate is generated by the above-mentioned sulfiding treatment, the treated product is subjected to solid-liquid separation using a filter press to recover a liquid component.

The compositions of the sulfurized liquid and the solid content of sulfides thus obtained are shown in Tables 7 and 8 below, respectively.

As is clear from Tables 7 and 8 above, virtually no arsenic is detected in the liquid obtained after the sulfurization treatment, and therefore,
It is confirmed that the removal of arsenic from the indium-containing material has been achieved.

Claims (1)

[Claims] 1. Neutralize the sulfuric acid leachate of the indium-containing material with an alkali in the presence of a reducing agent to pH 3 to 4, and treat the resulting precipitate with an alkali in the presence of hydrogen peroxide to bring the pH to 13.
As described above, the alkali-treated product is subjected to solid-liquid separation to remove the liquid, the resulting solid content is then dissolved in sulfuric acid, and the dissolved product is subjected to solid-liquid separation to remove the solid content. A method for separating and removing arsenic from an indium-containing material, which comprises sulfurizing a liquid component and separating the sulfurized product into solid-liquid to remove the solid component.