JPH0557206B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for precipitating and recovering indium from a basic solution containing sulfide in which indium is dissolved. More specifically, it relates to a method for recovering indium, which comprises precipitating indium hydroxide by oxidizing the sulfide in the basic solution when recovering indium from a basic solution containing sulfide in which indium is dissolved. Conventionally, indium is recovered from an aqueous solution containing dissolved indium, for example, by performing various purification treatments on the leachate obtained by leaching indium-containing ores with acid, and then neutralizing it with a base to recover indium hydroxide. How to
158128, Japanese Patent Application Laid-Open No. 158125) are generally adopted. In this known method, in order to precipitate indium, it is necessary to neutralize the highly concentrated and large amount of acid used to elute indium from the ore with a base, so the cost of the chemicals used for neutralization is enormous. This method has disadvantages in that it is uneconomical and other metals present in the leachate are simultaneously neutralized and precipitated in the recovered indium hydroxide, resulting in only indium hydroxide of low purity being obtained. The present inventors previously discovered that a chelating agent having a functional group containing a phosphorus atom efficiently adsorbs indium in a solution, and proposed a method for recovering indium (Japanese Patent Laid-Open No. 172256/1983). Public bulletin),
Furthermore, as a method for eluting metals adsorbed onto chelating agents having special functional groups, we proposed a method for increasing the elution efficiency by using an aqueous base solution containing sulfide as the eluent. 59-164021). In this method, to recover indium from an indium eluent, the eluent is neutralized with a salt and indium hydroxide is precipitated and recovered, so there is still contamination of other metals and consumption of acids and bases. There is a problem. In view of such circumstances, the present inventors have developed a large amount of acid,
As a result of intensive research to find a method for recovering indium with relatively high purity without consuming base, we have developed an adsorbent that adsorbs indium ore or indium using a base solution containing sulfide as an extractant. By dissolving or eluting indium, indium can be dissolved or eluted while hardly dissolving or eluting other heavy metals, and the indium thus obtained oxidizes sulfide in a basic solution containing dissolved sulfide. The inventors have discovered that indium can be precipitated as a hydroxide by this method, and have completed the method of the present invention. That is, in recovering indium from a basic solution containing sulfide in which indium is dissolved, the present invention precipitates the indium in the basic solution as indium hydroxide by oxidizing the sulfide in the basic solution. The present invention relates to a method for recovering indium, which is characterized by: The basic solution containing sulfide in which indium is dissolved to be used in the method of the present invention is not particularly limited, but in general, indium is eluted from an adsorbent that has adsorbed indium with a basic solution containing sulfide. Examples include leachate in which indium is eluted from indium-containing ore, scrap, etc. with an aqueous base solution containing sulfide. The concentration of indium in the above basic solution is not particularly limited as long as indium is dissolved, but
Generally, 0.01 g/or more is used.
It is possible to use indium with an indium concentration of 0.01g/or less, but as the concentration decreases, the amount of indium recovered per unit solution volume decreases, and excessive separation takes more time than necessary, which reduces production efficiency. Undesirable. Sulfide in the base solution has the effect of increasing the elution efficiency of indium and reducing the dissolved concentration of other metals, and is an extremely important factor in recovering high purity indium. If only a basic solution is used, the elution of indium is so low that it does not substantially occur, and a large amount of impurity elements are mixed in, which is not preferable. Examples of sulfides include water-soluble inorganic sulfides such as sodium sulfide, sodium bisulfide, ammonium sulfide, hydrogen sulfide, potassium sulfide, ammonium hydrogen sulfide, sodium hydrogen sulfide, lithium sulfide, barium sulfide, magnesium sulfide, and alkali polysulfide. It will be done. The concentration of sulfide varies depending on the amount and type of indium and basic compound in the solution, but is generally at least an equivalent of the indium content in the solution, preferably at least 3 times the equivalent. It is usually used at a sulfide concentration of 0.005 to 3N. The base solution is used to elute or dissolve indium from an adsorbent such as a chelate resin, ore or scrap more efficiently than when using a sulfide solution alone. Examples of such basic compounds include inorganic alkali compounds such as sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, and ammonia, and water-soluble organic amines such as ethylenediamine, diethylenetriamine, diethylamine, and triethylamine. As the solution containing the sulfide and basic compound, an aqueous solution is generally used, but it may also contain an organic solvent. The base concentration of the base solution is generally 0.1 normal concentration or higher. According to the method of the present invention, indium can be recovered from a basic solution containing sulfide in which indium is dissolved, without using any neutralization means, and without substantially eliminating the basic compound. That is, by oxidizing the sulfide in the base solution, indium is precipitated and recovered as a hydroxide.
A method for oxidizing sulfide in a basic solution containing sulfide in which indium is dissolved is to add air, oxygen, hydrogen peroxide, ozone, sodium hypozinc chloride, calcium chlorate, hypobromite to the solution. Acid soda, chlorine, bromine, potassium permanganate, sodium dichromate, ammonium perchlorate, potassium perchlorate, sodium perchlorate, magnesium perchlorate, sodium peroxide, potassium peroxide, calcium peroxide, peroxide A method of oxidizing sulfide by blowing in or adding an oxidizing agent such as barium, a method of oxidizing sulfide electrochemically, etc. can be implemented. Among these, oxidation methods using oxidizing agents such as air, oxygen, hydrogen peroxide, ozone, hypochlorite, perchlorate, alkali metal peroxide, alkaline earth metal peroxide, chlorine, and bromine are preferably used. The removal of the sulfide in the base solution by oxidative decomposition is carried out using a chemical or the like in an amount equal to or more than the sulfide. The treatment temperature varies depending on the type and amount of the drug, but is usually 0 to 300°C, and is generally carried out at room temperature.
Although it is possible to carry out the reaction at a temperature of 0° C. or lower, it is not preferable because the reaction rate between the sulfide and the drug becomes slow. Further, the reaction can be carried out under normal pressure or increased pressure. The treatment time for the sulfide and the chemical varies depending on the treatment temperature, the type and amount of the chemical, and these conditions can be set by conducting preliminary experiments. Usually it is in the range of 5 minutes to 24 hours. When the sulfide in a basic solution containing sulfide in which indium is dissolved is oxidized by the method of the present invention, the combination ratio of indium and sulfide in the solution is disrupted, and indium is precipitated as indium hydroxide. Further, it has the advantage that it does not cause loss of the base used to increase the elution efficiency during elution. The indium hydroxide thus obtained is then over-separated by a known method such as centrifugal dehydration, super decanter, decantation or the like. And the over-separated indium hydroxide is
It can be used as it is or if necessary, washed with water, purified and dried, or further dissolved and subjected to electrolytic treatment and reduction treatment.
Recovered as indium metal. The basic solution containing almost no dissolved indium and sulfide after over-separating indium hydroxide can be reused as an eluent for indium from ores, scraps, etc., or as an eluent for indium adsorbents by adding sulfide. can be used. Thus, the method of the present invention does not involve the consumption of large amounts of acids and bases compared to known methods;
Indium of relatively high purity can be efficiently recovered with simple operations, and its industrial value is extremely large. Hereinafter, the method of the present invention will be explained with reference to examples, but the present invention is not limited to the following examples. Example 1 Zinc smelting process with a pH of 0.7 containing 0.098 g of indium, 126 g of zinc, 11 g of manganese, and 8 g of iron.50% of the sulfuric acid leachate of lead slag was converted into a chelate resin sumichelate having an aminomethylene phosphonic acid group.
The solution was passed through a column packed with MC-100 (manufactured by Sumitomo Chemical Co., Ltd.) 2 for 8 hours. Next, 20 g of a mixed aqueous solution of 0.04N ammonium sulfide and 2N potassium hydroxide was poured over the resin for 4 hours, and the effluent was sequentially filtered. Thus indium 0.20g/, zinc 0.006
g/, less than 0.016 g/ of iron, 0.001 g/ of manganese, and 1.98 containing ammonium sulfide of 0.031 standard.
Eluent consisting of a specified potassium hydroxide aqueous solution 20
I got it. Next, 30 g of hydrogen peroxide solution with a concentration of 35% by weight was added to the eluent 5, stirred at 60°C for 30 minutes, filtered and dried to obtain 1.40 g of white indium hydroxide with a purity of 99.3% (indium yield 96% based on the eluent). )and
A 1.98N potassium hydroxide aqueous solution 5.0 was obtained. Examples 2 to 5 The oxidizing agent shown in Table 1 was added to the eluent 5 obtained in Example 1, and after stirring at room temperature for 3 hours,
After filtering and drying, the results shown in Table 1 were obtained.

[Table] Example 6 Indium 0.90g/, Zinc 47g/, Arsenic
A sulfuric acid leachate of lead slag, a by-product of the smelting process of cadmium with a pH of 0.8, containing 7.3 g/, iron 0.8 g/, and manganese 2.3 g/diethylenetriamine was added to Sumikylate, a chelate resin having methylenephosphonic acid groups.
It was left in contact with MC-95 (manufactured by Sumitomo Chemical Co., Ltd.) 2 for 20 hours and then passed. Next, the resin was packed into a column having an inner diameter of 5 cm, and a 20% aqueous sulfuric acid solution 125 was allowed to flow down for 2 hours to elute and remove metals other than indium.
Then, a mixed aqueous solution of 0.02N sodium sulfide and 1N sodium hydroxide at 80°C was added to the resin.
was allowed to flow down for 6 hours, and an eluate consisting of a 0.99N sodium hydroxide aqueous solution containing 1.31g of indium, 0.013g of zinc, 0.024g of iron, 0.001g of manganese and arsenic, and 0.019N of sodium sulfide. Liquid 12 was obtained. Next, oxygen from the eluents 1 and 10 was charged into an autoclave, treated under 14 kg/cm ² pressure at 150°C for 2 hours, cooled, filtered, and dried to obtain a white product with a purity of 99.5% (95% indium yield based on the eluent). 1.8 g of indium hydroxide and a 0.99N aqueous sodium hydroxide solution 1 were obtained. Examples 7 to 9 Eluent 1 of Example 6 was oxidized under the conditions shown in Table 2, filtered and dried, and the results shown in Table 2 were obtained.

[Table] Comparative Example 1 2460 g of 20% sulfuric acid aqueous solution was added to Eluent 5 having the same composition as Examples 1 to 5, stirred for 1 hour, filtered and dried, and 1.49 g of dark brown indium hydroxide with a purity of 89% was obtained.
and an aqueous solution of pH 5.1 and 7.4 was obtained. (Indium yield based on eluent: 92%) Comparative Example 2 370 g of 10% hydrochloric acid aqueous solution was added to eluent 1 having the same composition as Examples 6 to 9, and after stirring at room temperature for 30 minutes,
By over-drying, 1.83 g of gray-brown indium hydroxide with a purity of 94% (indium yield 91%) and 1.3 g of an aqueous solution with a pH of 5.4 were obtained. From Examples 1 to 9 and Comparative Examples 1 to 2, the indium recovery method of the present invention has the following advantages compared to known methods:
It is clear that relatively pure indium can be recovered in high yield without consuming large amounts of acids and bases.

Claims (1)

[Claims] 1. A method for recovering indium from a basic solution containing sulfide in which indium is dissolved, characterized in that indium hydroxide is precipitated by oxidizing the sulfide in the basic solution. How to recover indium. 2 The concentrations of sulfide and base of a base solution containing sulfide with dissolved indium are respectively
The method for recovering indium according to claim 1, characterized in that the indium concentration is 0.005 to 3N and 0.1N or more. 3 Air, oxygen,
Claim 1, characterized in that an oxidizing agent selected from hydrogen peroxide, ozone, hypochlorite, perchlorate, alkali metal peroxide, alkaline earth metal peroxide, chlorine and bromine is used. The method for recovering indium according to item 1 or 2.