JPH0310031A - Method for extracting and separating cobalt from cobalt-nickel oxide - Google Patents

Abstract

PURPOSE:To unnecessitate the addition of an alkali from the outside and to contrive to save energy based on the occurrence of a reaction at a low temp. by directly dissolving Co to extract and separate from mixed oxide of Co and Ni by an organic soln. including alkyl phosphoric acid. CONSTITUTION:Co-Ni mixed oxide having the shape of CoO and NiO is brought into reaction with an organic soln. of aliphatic hydrocarbons, aromatic hydrocarbons, etc., including alkyl phosphoric acid such as bis-2-ethylhexyl phosphate at a prescribed stirring rate and a reaction temp. to selectively dissolve and extract Co. Then, after the completion of the reaction, the extracted Co is back-extracted by sulfuric acid or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION In the conventional method, after dissolving an acidic solution under high temperature and high pressure, an alkali must be added to adjust the pH range to which the solvent extraction method can be applied. Fortunately, consumption determines the economics of the process.

[Means for Solving the Problem] The present inventor has discovered that cobalt oxide can be dissolved at a relatively low temperature by using an organic solution containing alkyl phosphoric acid. A method of obtaining a share is being considered. However, these methods mainly involve dissolving cobalt and nickel with a mineral acid such as sulfuric acid under high temperature and pressure, and then using a solvent extraction method from the leachate to separate cobalt and nickel.

[Problem to be solved by the invention]

Those having an alkyl group having 6 or more carbon atoms, such as bis-2-ethylhexyl phosphate and bis-2-dodecyl phosphate, are used. As an organic solvent for diluting these, alkyl mW
Any substance that mixes well with & may be used, such as aliphatic hydrocarbons and aromatic hydrocarbons. Moreover, the cobalt oxide and the nickel oxide are each Co.

and NiO.

In the present invention, cobalt is selectively dissolved and extracted by reacting alkyl phosphoric acid diluted with an organic solvent with cobalt and nickel oxide, but in this case, D2EHPA 11 degrees is 1%
~50%, preferably about 10%, and the reaction temperature is 50%.
After completion of the reaction at a temperature below 0''C, preferably below 30°C, the extracted cobalt is back-extracted with sulfuric acid.

[Effects/Applications of the Invention] A xylene solution containing D2EHPA was reacted with cobalt and nickel oxides each having a solid-liquid ratio of 5 g/l and a particle size of 200 mes h or less at a stirring speed of 900 rpm and a reaction time of 72 hours. Table 1 shows the extraction rates of cobalt and nickel. In addition, the chemical species of extracted cobalt was examined using a spectrophotometric needle, and it was found that it formed a tetrahedral complex.

Suitable for the processes in Table 1. Moreover, the organic solution containing alkyl phosphoric acid has the advantage that it can be used after cobalt back extraction. Furthermore, the present invention is suitable for separating cobalt and nickel.

[Example] Next, examples of the present invention will be shown.

Example 1 Bis-2-ethylhexyl phosphate with a volume concentration of 10% Example 2 A xylene solution containing D2EHPA with a volume concentration of 10% and cobalt and nickel oxides each having a solid-liquid concentration of 5 g/l and a particle size of 200 mesh or less were stirred. Table 2 shows the results of examining the effect of reaction time on the extraction rate of cobalt and nickel when the reaction was carried out at a pumping speed of 900 rpm and a reaction temperature of zO<0>C.

Table 2 Various D2EHPA 11 degree xylene solutions and solid-liquid concentration 5
g/l, cobalt oxide with a particle size of 200 mesh or less, stirring speed 900 rpm, reaction temperature 2
Table 3 shows the influence of the D2EHPA concentration on the cobalt extraction rate when the reaction was carried out at 0°C for a reaction time of 72 hours.

Table 3 As can be seen from Table 2, when the reaction temperature was 20°C, the reaction proceeded rapidly after 30 hours; when the reaction temperature was 30°C, the reaction proceeded rapidly after 50 hours;
In the case of 'C, the reaction did not progress much even after 72 hours of reaction.

Example 3 In addition, a similar study was conducted on nickel oxide, and it was found that
As the D2EHPA concentration increased, its extractability decreased, but in any case, the extractability was very low.

[Comparative Example] A xylene solution of mono-2-ditylhexyl 2-ethylhexylphosphonate (EHEHPA) with a volume concentration of 10% was mixed with cobalt and nickel oxides each having a solid-liquid concentration of 5 g/l and a particle size of 2° Omesh or less. When the reaction temperature was 20℃, the reaction time was 72 hours, and the stirring speed was 900 rpm, the extraction rate of cobalt was 1.4% and that of nickel was 0.3%.
%Met. Moreover, almost no influence of the reaction temperature and EHEHPAi of 1 degree was observed.

Claims (1)

[Claims] 1. A method for directly dissolving and extracting cobalt from cobalt and nickel mixed oxide using an organic solution containing alkyl phosphoric acid.