JPH0310032A - Method for extracting and separating cobalt from cobalt-nickel oxide by organic-water solution including alkyl phosphoric acid - 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 relatively low temp. by directly dissolving Co to extract and separate from mixed oxide of Co and Ni by using an organic soln. including alkyl phosphoric acid in the presence of water. CONSTITUTION:Co-Ni oxide having the shape of CoO and NiO is brought into reaction with a soln. constituted of an organic soln. of which bis-2-ethylhexyl phosphate or the like as alkyl phosphoric acid is diluted with an organic solvent such as aliphatic hydrocarbons and water, by which Co is selectively dissolved and is extracted into the organic soln. At this time, cobalt oxide is utilized, in itself, as a base and proton released by alkyl phosphoric acid at the time of extracting Co as an acid. In this case, the concn. of alkyl phosphoric acid and the solid-liquid concn. of Co oxide are suitably regulated. After the completion of the reaction, Co extracted into the organic soln. is simply backextracted by sulfuric acid or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for selectively dissolving and extracting cobalt from nickel by using a solution system consisting of an organic solution containing an alkyl phosphoric acid and water from a mixed oxide of cobalt and nickel. It is.

[Problem to be solved by the invention] In the conventional method, after dissolving using mineral acid under high temperature and high pressure,
In order to adjust the pH to a pH range where the solvent extraction method can be applied, an alkali must be added. [Prior Art] Conventionally, methods of recovering cobalt and nickel from the Ellization section have been studied. However, the inventor
We considered dissolving and extracting cobalt from cobalt oxide at a relatively low temperature by using an organic solution containing alkyl phosphoric acid in the presence of water and using cobalt oxide itself as a base. The present invention was developed after conducting studies on its use in separation. Examples of the alkyl phosphoric acids used in the present invention include bis-phosphoric acid.
Those having an alkyl group having 6 or more carbon atoms, such as 2-ethylhexyl and bis-2-dodecyl phosphate, are used. The organic solvent for diluting these may be one that mixes well with the alkyl phosphoric acid and has low solubility in water. can be found. Moreover, the cobalt oxide and the nickel oxide are each Co.

In the present invention, a solution system consisting of alkyl phosphoric acid and water diluted with an organic solvent is used by reacting with cobalt and nickel oxides.
There is no need to add alkali from the outside, the reaction occurs at a relatively low temperature, and energy consumption is low.Also, cobalt extracted into an organic solution can be easily back-extracted with sulfuric acid.

Suitable for subsequent processes such as electrolysis. Furthermore, the organic solution containing alkyl phosphoric acid has the advantage that it can be reused after back-extracting cobalt. Furthermore, the present invention is suitable for separating cobalt and nickel.

Uses protons as acids. In this case, alkyl phosphorus a
Appropriate S degree and solid-liquid concentration of cobalt oxide. The initial pH of water is preferably 1.5 or higher; the reaction temperature is preferably 50° C. or higher; and 0. After the reaction is completed, the cobalt extracted into the organic solution can be easily back-extracted with sulfuric acid.

[Effects and Applications of the Invention] According to the present invention, a solution system consisting of an organic solution consisting of a xylene solution containing cobalt oxide itself as a base and tylhexyl (D2EHPA) and an equal volume of water, each with a solid-liquid concentration of 2.5
The leaching rate and leaching rate of cobalt and nickel oxides when cobalt and nickel oxides with a particle size of 200 m e sh or less were reacted at a stirring speed of 900 rpm, a reaction time of 6 hours, and a reaction temperature of 2 degrees at 70°C. Table 1 shows the influence of the initial pH of the filtrate on the cobalt concentration in the organic solution.

Table 1 Table 2 shows the effect of reaction temperature on leaching rate and cobalt 1 degree in organic solution.

Table 2 Example 2 A solution system consisting of an organic solution consisting of a xylene solution containing D2EHPA with a volume concentration of 10% and an equal volume of water (initial pH 6), a solid-liquid degree of 2.5 g/l, and a particle size of 200 ma s.
h or less of cobalt and nickel oxides at a stirring speed of 9
Table 3 shows the effects of reaction time on the leaching rate of cobalt and nickel oxide when reacted at 00 rpm and reaction time of 6 hours, the leaching rate of cobalt and nickel oxide at a reaction temperature of 70°C, and the cobalt concentration in the organic solution. However, the other reaction conditions are the same.

Table 3 Table 4 Example 3 Solution system consisting of equal volumes of organic solution and water (initial pH 6), each solid-liquid concentration 2.5 g/l, particle size 200 m e s
Table 4 shows the influence of 1 degree of D2EHPAI in the organic solution when cobalt and nickel oxides of 1 h or less were reacted at a stirring speed of 900 rpm, a reaction time of 6 hours, and a reaction temperature of 70°C.

Claims (1)

[Claims] 1. A method for selectively directly dissolving and extracting cobalt from cobalt and nickel oxides by using an organic solution containing alkyl phosphoric acid in the presence of water.