JPH0776394B2 - Extraction and separation of cobalt from cobalt and nickel oxide - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for directly dissolving and extracting cobalt from a mixed oxide of cobalt and nickel with an organic solution containing alkylphosphoric acid.

[Prior Art] Conventionally, a method of recovering cobalt and nickel from oxide ore or the like has been studied. However, they are a method in which cobalt and nickel are separated from the leachate by a solvent extraction method, after being melted at a high temperature and a high pressure, mainly by ores of sulfuric acid or the like.

[Problems to be Solved by the Invention] In the conventional method, an oxide ore or the like is dissolved under high temperature and high pressure using an acidic solution such as a mineral acid, and then an alkali is added to adjust the pH range to which the solvent extraction method can be applied. There is a problem in that its energy and alkali consumption affect the economics of the process.

[Means for Solving the Problems] The present inventors have found that if an organic solution containing alkylphosphoric acid is used, the cobalt oxide is dissolved and extracted at a relatively low temperature, and this is used for separation of cobalt and nickel. Therefore, the present invention has been completed.

As the alkylphosphoric acid used in the present invention, for example, bis-2-ethylhexyl phosphate, bis-2-dodecyl phosphate or the like having an alkyl group having 6 or more carbon atoms is used.
The organic solvent for diluting these may be any solvent that mixes well with allylic phosphoric acid, and examples thereof include aliphatic hydrocarbons and aromatic hydrocarbons. Cobalt oxide and nickel oxide are Co
It has the forms of O and NiO.

In the present invention, an alkylphosphoric acid diluted with an organic solvent is reacted with cobalt and nickel oxide to selectively dissolve and extract cobalt, and then extracted into an organic solution. At this time, cobalt oxide itself is used as a base, The protons released by alkyl phosphoric acid during cobalt extraction are used as acids. In this case, the D2EHPA concentration is 1% to 50%, preferably about 10%, and the reaction temperature is 50 ° C or lower, preferably 30 ° C or lower. After completion of the reaction, the extracted cobalt is back-extracted with sulfuric acid.

[Advantages and Uses of the Invention] According to the present invention, extraction does not require dissolution using an acidic solution such as a mineral acid or addition of an alkali from the outside, and further, a reaction occurs at low temperature and energy consumption is small. Further, the extracted cobalt can be easily back-extracted with sulfuric acid, which is suitable for subsequent processes such as electrolysis. Moreover, the organic solution containing alkyl phosphoric acid has an effect that it can be reused after the back extraction of cobalt. Further, the present invention is suitable for separating cobalt and nickel.

[Examples] Next, examples of the present invention will be described.

Example 1 Bis-2-ethylhexyl phosphate (D2EHP) having a volume concentration of 10%
Xylene solution containing A) and solid-liquid concentration of 5g / l, particle size 200me
Stirring speed of cobalt and nickel oxide below sh is 90
Table 1 shows the extraction rates of cobalt and nickel when the reaction was performed at 0 rpm and a reaction time of 72 hours. As a result of investigating the extracted species of cobalt with a spectrophotometer, a tetrahedral complex was formed.

Example 2 A xylene solution containing 10% by volume of D2EHPA and a solid-liquid concentration of 5 g / l and cobalt and nickel oxides each having a particle size of 200 mesh or less were reacted at a stirring speed of 900 rpm and a reaction temperature of 20 ° C. Table 2 shows the results of examining the influence of the reaction time on the extraction rates of cobalt and nickel.

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 is 30 ℃,
The reaction proceeded rapidly after 50 hours, and when the reaction temperature was 50 ° C., the reaction did not proceed so much even after 72 hours of reaction.

Example 3 Xylene solutions with various D2EHPA concentrations, solid-liquid concentration of 5 g / l, and particle size
Cobalt oxide of 200 mesh or less, stirring speed 900 rpm,
Table 3 shows the effect of the D2EHPA concentration on the extraction rate of cobalt when the reaction was carried out at a reaction temperature of 20 ° C. and a reaction time of 72 hours.

Also, when the same examination was conducted for nickel oxide,
The extractability decreased with increasing D2EHPA concentration, but in any case the extractability was very low.

[Comparative Example] 2-ethylhexylphosphonic acid mono-2-ethylhexyl (EHEHPA) in a xylene solution having a volume concentration of 10% was solid-liquid concentration of 5 g / l, cobalt and nickel oxide having a particle size of 200 mesh or less, and a reaction temperature of 20 ° C. Reaction time 72 hours, stirring speed 90
When reacted at 0 rpm, the extraction rate of cobalt was 1.4% and that of nickel was 0.3%. The effects of reaction temperature and EHEHPA concentration were hardly seen.

Claims (1)

[Claims] 1. A method for directly dissolving, extracting and separating cobalt from cobalt and nickel mixed oxides using an organic solution containing alkylphosphoric acid.