JP2531695B2 - Recovery method for valuable substances - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention separates valuable substances such as arsenic and antimony in dust generated during vacuum refining of a molten mat in a sulfur-containing copper smelting process. The present invention relates to a method of recovering valuable materials that can be recovered by increasing the degree of infiltration of each composition.

(Prior Art) Various reports have been made regarding the method of treating substances generated during the smelting of non-ferrous metals, but for substances containing arsenic, antimony, and sulfur as the main components, each composition should be selected from those substances. There is a method of concentrating and separating and collecting.

(Problems to be Solved by the Invention) However, the method of the above configuration is not sufficient, and an appropriate processing method has not been found. For example, substances such as slag produced by the smelting process of copper having arsenic, antimony, and sulfur as the main components in the present invention are mainly treated by the flotation method.

In the flotation method, although copper is recovered in a considerable yield, some of the arsenic, antimony, bismuth, etc. that were once removed in the converter slag are repeatedly sent to the smelting furnace for smelting. Since the processing capacity of the smelting furnace is being pressed and the tailings generated from the flotation process have limited applications,
The processing is also becoming a problem.

On the other hand, in the copper smelting process, arsenic and antimony, which have been conventionally expressed as impurities, have recently attracted attention as constituent elements of functional materials, and it has become necessary to secure them as a raw material source.

Furthermore, when the sulfide dust generated by vacuum purification is left as it is for a long time, the existing arsenic is oxidized by aging, which leads to the generation of arsenous acid, which becomes a pollution source and sometimes even a large amount of human life. It had many harmful effects on the environment and safety management.

From the above requirements, it has been emphasized that each composition needs to be concentrated and separated and recovered from a substance containing arsenic, antimony, and sulfur as main compositions.

(Means for Solving Problems) In order to solve the problems of the above-mentioned conventional techniques, the present invention does not include sulfur content in dust generated when vacuum-refining a molten mat containing sulfur content in a copper smelting process. After treatment with an alkaline solution, the pH and solution temperature of the solution can be adjusted to separate into a solution and a precipitate, and the composition of arsenic and antimony in the treated substance can be easily purified in the next step. In addition to the separation and recovery in the form of sulfides, dusts, etc., are prevented from causing pollution accidents due to the generation of arsenous acid and the like from the substances and natural emission in the atmosphere, which are observed when the substances are piled up.

That is, the present invention is a dust generated when vacuum-refining a molten mat in a copper smelting step containing a sulfur content, and when vacuum-refining a molten mat in a copper smelting step containing a sulfur content of about 22%. Generated, arsenic 5-30% by weight, antimony 5-30% by weight, lead 0-5% by weight, copper 2-
It is intended to separate and recover valuable substances such as arsenic and antimony for sulfide dust having a composition of 10% by weight and 20 to 50% by weight of sulfur.

More specifically, in the present invention, dust generated during vacuum refining of a molten mat in a copper smelting process containing a sulfur content is immersed in a sulfur-free alkali, for example, an alkaline solution such as caustic soda. After the solution
By adjusting the pH to 10 or more, the liquid temperature to 60 to 80 ° C, and the arsenic concentration in the leachate to 20 g / l or less, the arsenic and antimony in the substance are sufficiently leached into the leachate. After that, the unreacted residue is separated and removed, and the pH of the leachate is adjusted to 7.0 to 9.5 by adding an acid such as sulfuric acid to the leachate after the residue is further separated. By separating the antimony and the sulfur-rich precipitate formed in (1) from the neutralization solution, arsenic is concentrated in the neutralization solution, and antimony is recovered as a precipitate.

(Function) In the alkali leaching step according to the present invention, the pH of the leachate is
Is limited to 10.0 or more, when the PH value is less than 10, the collection rate of antimony in the substance to be treated falls below 99.50% by weight, and it cannot be sufficiently leached into the leachate. This is because.

Also, the temperature of the leachate is kept at 60 to 80 ° C because the leaching speed of arsenic and antimony into the leachate is slow when the liquid temperature is lower than 60 ° C, and the workability of recovering valuables is improved. The reason for this is that when the liquid temperature exceeds 80 ° C., the leaching amount of unnecessary components leaching into the leachate becomes prominent, and the purity of the intended valuables is reduced. Also, the PH was limited to 7.0 to 9.5 in the neutralization step because the leaching of arsenic into the neutralization solution was not sufficient when the pH of the neutralization solution was less than 7.0, and in the neutralization solution when it exceeded 9.5. This is because the leaching of antimony into the steel becomes severe and it becomes difficult to separate arsenic and antimony. The arsenic concentration in the leachate
20g / l or less is defined as the arsenic concentration in the leachate is 20g / l
This is because, when it exceeds, the coprecipitation phenomenon of arsenic and antimony occurs in the leachate, which makes separation and recovery of both difficult. Then, the unreacted residue is separated and removed, which can enhance the quality of the recovered product.

(Example) An example will be described below.

Example 1 Arsenic 20.8% by weight, antimony 34.0% by weight and copper 8.07 generated when vacuum-refining a molten mat in a copper smelting process
%, Lead 0.24%, sulfur 36.8% sulfide dust
After crushing 400 g to 100 mesh or less, leaching treatment was performed for 2 hours at a liquid temperature of 80 ° C. while maintaining PH 10.50 with a caustic soda solution.

 The amount of liquid after leaching was 7.8 l and the amount of residue was 50 g.

Leachate quality is 10.6 g / l for arsenic and 16.5 g / l for antimony.
The quality of the residue is 0.9% by weight of arsenic and 15.
1% by weight, copper 58.1% by weight, lead 1.7% by weight, sulfur 20.9% by weight
It was.

As a result, 99% of arsenic in sulfide and antimony
94% was leached into the leachate.

After passing through the above-mentioned leachate and separating the residue, pH of the leachate was 7.5
The antimony in the neutralized solution with a total volume of 9.2 l was separated as a precipitate.

At this time, the quality of the produced neutralization liquid was 7.8 g / l for arsenic and 0.01 g / l or less for antimony. The amount of precipitate formed was 232 g after vacuum drying, and the composition was 4.7% by weight of arsenic, 55.3% by weight of antimony, and 38.9% by weight of sulfur.

As described above, according to the present invention, it is possible to recover a total amount of arsenic of 71.8 g as a neutralizing solution and antimony of 128.3 g as a precipitate.
We were able to secure 4.4% recovery.

Example 2 400 g of sulfide dust having the same composition as in Example 1 was crushed to 100 mesh or less, and then leached at a liquid temperature of 80 ° C. for 2 hours while maintaining PH 10.50 using a caustic soda solution.

The amount of liquid after leaching was 7.8 l and the amount of residue was 50 g. The leachate grades were arsenic 10.6 g / l and antimony 16.5 g / l, and the residue grades were arsenic 0.9 wt% and antimony 15.1 wt%.
Copper was 58.1% by weight, lead was 1.7% by weight, and sulfur was 20.9% by weight.

After the leaching solution was passed to separate the residue, the pH of the leaching solution was lowered to 8.0 while 5% sulfuric acid was added dropwise at room temperature to separate the antimony in the neutralization solution in a total volume of 9 l as a precipitate. did.

The quality of the neutralization liquid generated at this time was 9.2 g / l for arsenic and 6.0 g / l for antimony. The amount of precipitate formed was 136 g after vacuum drying, and the composition was 53.52% by weight antimony and 4% sulfur.
It was 4.4% by weight and contained only traces of arsenic.

As described above, according to the present invention, a total amount of arsenic 82.7 g as a neutralizing solution and 74.4 g of antimony as a precipitate can be recovered, and arsenic and antimony are 99.5% and 54.7%, respectively.
Was secured.

Comparative Example 1 400 g of sulfide dust having the same composition as in Example 1 was used to carry out alkali leaching in the same step, and the quality of the leachate obtained was arsenic 10.6 g / l and antimony 16.5 g / l. To this leachate, add 5% concentration of sulfuric acid water at room temperature while adding 1% of PH.
It was lowered to 0.0 to give a total volume of 8.0 l of neutralization solution.

However, the quality of the neutralization liquid generated at this time is
Since 10.3 g / l and antimony were 16.0 g / l, no precipitation was observed and antimony could not be separated from the neutralized solution.

Comparative Example 2 400 g of sulfide dust having the same composition as in Example 1 was used to carry out alkali leaching in the same step to the leachate obtained, and 5% concentration of sulfuric acid water was added dropwise at room temperature to pH 6.0. The total amount of neutralization solution and the precipitate was 9.8 l.

In this case, the quality of the neutralization solution contained no antimony, but contained only 3 g / l of arsenic. The quality of the precipitate is 17.6% by weight arsenic, 42.4% by weight antimony and 3% sulfur.
8.9% by weight, and arsenic recovered as a neutralizing solution is 35.
Only 4%, 64% by weight of arsenic and 94.4% by weight of antimony were mixed in the precipitate, which made it impossible to separate and recover the originally intended arsenic and antimony.

(Effects of the Invention) As described in detail above, according to the present invention, arsenic and antimony, which are valuable substances that are favored in the electronics industry, are more useful than sulfide dust generated in the copper refining process. Since it can be separated and collected very easily, there is an extremely great contribution to the electronic equipment industry.

Claims (1)

(57) [Claims] 1. Dust generated during vacuum refining of a molten mat in a copper smelting process containing sulfur is immersed in a sulfur-free alkaline aqueous solution having a pH of 10.0 or more and a temperature of 60 to 80 ° C., After leaching arsenic and antimony in the substance into the solution, the arsenic concentration in the leachate was adjusted to 20 g / l or less, the unreacted residue was separated and removed, and the leachate after separating the residue Acid to add PH of leachate to 7.0
A method for recovering valuable substances, which comprises adjusting the pH to 9.5 and separating the precipitate generated during pH adjustment from the solution.