JPS5810975B2 - Dogen Reiyouchi Yushiyutsu Yutsuekinoseihouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention removes iron, arsenic, and antimony from an extract obtained by extracting copper raw materials such as copper ore, slag, sludge, and trosmat with an acid, which contains impurities such as iron, arsenic, and antimony. This invention relates to a method for cleaning an extract.

When copper raw materials such as copper dross are extracted with sulfuric acid, heavy metals such as iron, arsenic, and antimony are extracted as impurities along with copper.

In this case, impurities such as iron are mostly dissolved in the liquid as Fe2+.

However, if a copper raw material extract containing such impurities is subjected to electrowinning as it is, these impurities will be gradually concentrated as the resulting electrolytic tail liquid is repeatedly subjected to the extraction process, which will adversely affect electrowinning.

In particular, iron significantly reduces current efficiency, resulting in an increase in power consumption, and arsenic and antimony mix into electrolytic copper, lowering the copper quality or causing cementation of copper in the extract. In this case, toxic gases of H3As and H3Sb are generated, which is extremely dangerous.

Therefore, in consideration of subsequent steps, a cleaning step is required to separate and remove iron, arsenic, and antimony from the extract.

Conventionally, as a method for cleaning the extract obtained by extracting copper raw materials with sulfuric acid, a bloodletting method was generally adopted in which the tail liquid containing concentrated impurities was extracted from the system to prevent the impurities from concentrating above a certain concentration during the copper electrowinning process. There is.

However, with this method, it is necessary to remove the produced copper sulfate by concentration, and because there is a large amount of copper remaining in the tailing liquid, there is a large loss of copper.Also, since the sulfuric acid concentration in the tailing liquid is high, it is necessary to neutralize the tailing liquid. Since the amount of neutralizing agent is enormous, it is not only uneconomical, but also the disposal of the residue is a problem, and even if it is intended to be commercialized as gypsum, it is not preferable because it contains many impurities.

On the other hand, the electrolytic refining process incorporates a cleaning process called dearsenization electrolysis.

However, this method requires high equipment and operating costs, and the produced copper electrodeposit also contains a large amount of As and SB, so it cannot be commercialized as electrolytic copper as it is.

Alternatively, a solvent extraction method using EHPA (di-2-ethylhexyl phosphoric acid), an organic carboxylic acid, or a liquid ion exchanger such as Lix 64 (trade name of General Mills Co., Ltd.) is also used.
Alternatively, organic carboxylic acids cannot be used for copper raw material extracts in which a large amount of Fe2+ coexists, and Lix64 is a solvent that is selective to copper, but has a slightly low ion exchange ability.

The present invention solves the above-mentioned problems all at once; there is almost no loss of copper, no special equipment or recovery operations are required, and high-purity copper can be produced economically with simple operations. The present invention provides a method for cleaning an extract obtained by extracting a copper raw material with an acid.

That is, in the method of the present invention, a copper raw material containing dissolved iron, arsenic, and antimony as impurities is extracted with an acid, and the extract is aerated or an oxidizing agent is added to oxidize the impurities, and then the pH of the solution is adjusted to 1. 5 to 4.0, phosphoric acid is added and stirred to precipitate and separate the impurities.

Since copper precipitates in a pH range similar to that of iron, arsenic, and antimony, it is difficult to separate copper from a mixed aqueous solution containing these heavy metals only by adjusting the pH.

By the way, in the case of a metal such as zinc, even if iron, arsenic and antimony coexist, they can be separated by adjusting the pH and using an oxidizing agent.

That is, in this case, arsenication and antimony can be removed by coprecipitation at pH 2, and then iron can be removed by adding an oxidizing agent at pH 5.2.

This is because iron, arsenic, and antimony precipitate in acidic conditions, but zinc does not precipitate in acidic conditions, so it can be separated using an oxidizing agent, but in the case of copper, as shown in Figure 1, Since the pH range in which iron, arsenic, and antimony precipitate is similar to that in which they precipitate, they cannot be separated even if the pH of the liquid is adjusted using an oxidizing agent.

However, according to the present invention, after oxidizing iron, arsenic and antimony, adjusting the pH to 1.5 to 4.0 and further using phosphoric acid, a mixed aqueous solution containing copper, iron, arsenic and antimony is extracted. It has been found that copper can be isolated.

The present invention is based on such knowledge.

In the present invention, first, impurities in an extract obtained by extracting a copper raw material with an acid are oxidized.

That is, during this oxidation process, dissolved impurities such as Fe2
+ is oxidized to Fe3+.

Oxidation is carried out by aeration or addition of an oxidizing agent.

When performing oxidation by aeration, in order to complete the process in a short time, it is necessary to pass through as fine air bubbles as possible and to
It is preferable to heat to 0° C. or higher.

The aeration device may be any device that generates air bubbles, such as a foamer or a flotation device.

On the other hand, when oxidizing with an oxidizing agent, there is no particular need for heating, and room temperature is sufficient.

The oxidizing agent may be one commonly used, such as KMnO4, 2Cr207. Examples include MnO2.

The appropriate amount of the oxidizing agent added is 5 equivalents or more relative to dissolved iron, arsenic and antimony.

In the present invention, it is even more effective to use aeration and an oxidizing agent together.

Next, after adjusting the pH of the oxidized extract to a range of 1.5 to 4.0, phosphoric acid is added and stirred to precipitate impurities.

The stirring time is about 30 minutes, and the amount of phosphoric acid added is
An amount equivalent to the e-meter is sufficient.

For example, in the case of Fe3+, the reaction at this time is expressed by the following formula.

p) (Adjustment is done with sulfuric acid and hydrochloric acid.

In order to almost completely precipitate the impurities in the liquid and suppress the precipitation of Cu, the pH should be set to 1.5 to 4.0, preferably to a value that reduces the precipitation rate of impurities such as Fe, Sb, and As, as shown in Figure 2. 90
% or more, it is appropriate to set the pH to 2 to 3, at which Cu is almost in a liquid state.

Figure 2 shows the change in pH under oxidation conditions due to aeration at 80°C and the precipitation rate of each heavy metal due to the addition of phosphoric acid - (Pure content in the precipitate) x 100 / (Pure content in the solution after treatment) Although the results show the pure content in the precipitate, almost the same results can be obtained in the case of oxidation with an oxidizing agent (at room temperature).

Examples are shown below.

It is shown that a high temperature is better, and a pH of about 3 is better.

Example 1 Copper extraction stock solution (Cu: 38.24g/11, F
e: 4.02g/l, AS: 0.825g/l, sb
:0.02g/l) was subjected to a beaker test under the following test conditions, and the results are shown in Table 1 and FIG.

These results show that for iron, when increasing the amounts of H3PO4 and KMnO4 added and when performing aeration, the precipitation rate is high, the temperature is better at a higher temperature, and the pH is better at about 3.

Example 2 Next, based on the results of the beaker test of Example 1, a medium test was conducted with the pH set to around 3 and the amount of H3PO4 added.

That is, copper-containing dross (Cu50-60%, Pb25-30%
, As 1.5-2%.

SbO, 5-1.0%, Fe1-2%, Zn2-5%)
was extracted with sulfuric acid to obtain an extract as shown in Table 2.

This extract was aerated for about 3 hours using a flotation machine at room temperature, and after adjusting the pH with sulfuric acid as indicated, phosphoric acid was added, and the following results were obtained.

[Brief explanation of drawings]

Figure 1 is a curve diagram showing the precipitation rate of Cu, Fe, As, and sb due to differences in pH, and Figure 2 is a curve diagram showing the precipitation rate of Cu, Fe, As, and sb due to differences in pH in the single-row method of the present invention. The figures and FIGS. 3A to 3E are curve diagrams showing the sedimentation rate for each factor in the beaker test.

Claims (1)

[Claims] 1. A copper raw material containing dissolved iron, arsenic, and antimony as impurities is extracted with an acid, and the impurities are oxidized by aeration or an oxidizing agent, and then the pH of the solution is adjusted to 1.5 to 4. 1. A method for cleaning a copper raw material extract, which comprises adjusting the copper raw material extract to zero, and then adding and stirring phosphoric acid to separate the impurities by precipitation.