Method for improving grade of crude product of cobaltous hydroxide

Abstract

The invention discloses a method for improving the grade of a crude product of cobaltous hydroxide. A cobalt-containing solution is processed in three sections to obtain high-quality cobaltous hydroxide; enabling the pH of a first-section cobalt precipitation liquid to be about 7.50 by controlling the addition of magnesium oxide, taking a first-section cobalt precipitation residue as a product; adding the magnesium oxide into the first-section cobalt precipitation liquid to implement second-section cobalt precipitation, controlling the pH of a second-section cobalt precipitation liquid to be about 8.00, wherein a second-section cobalt precipitation residue returns to the first section to serve as a crystal seed, repeating the steps; continuing to process the second-section cobalt precipitation liquid by using calcium oxide and the magnesium oxide, returning a third-section cobalt precipitation residue as an alkali source to the leaching process, and conveying a third-section cobalt precipitation liquid to a sewage treatment plant. The cobalt solution with higher manganese content and magnesium content is processed to obtain the crude product of the cobaltous hydroxide, the cobalt grade of the crude product of the cobaltous hydroxide is about 44%, the manganese grade is about 1.0%, and the magnesium grade is about 2.5%, the purposes of improving the quality of cobaltous hydroxide and reducing the manganese and magnesium impurities are fulfilled, and the extracting cost and the transportation cost in the later period are reduced.

Description

technical field [0001] The invention belongs to the field of hydrometallurgy and relates to a method for improving the grade of crude cobalt hydroxide. Background technique [0002] There is a serious shortage of cobalt resources in my country. In order to solve the problem of domestic cobalt shortage, some domestic enterprises import cobalt raw materials from African countries such as Zambia and the Democratic Republic of the Congo. However, the industrial foundation of the Democratic Republic of the Congo is too weak. Most domestic enterprises use in-situ leaching. Crude cobalt salts are transported back to China for deep processing into various cobalt products. [0003] The applicant adopts the existing cobalt sinking process, and the cobalt grade in the crude cobalt hydroxide transported back from the Democratic Republic of the Congo is 35-40%, about 3.5% manganese, and about 5.0% magnesium, and the grade of cobalt is not high and unstable, manganese and magnesium Proble...

AI Technical Summary

Problems solved by technology

The quality of crude cobalt hydroxide obtained by this method is poor, and the extraction cost is increased in the later stage. The difference between the second-stage crude cobalt hydroxide and the first-stage crude cobalt hydroxide is relatively large, and the content of manganese and magnesium in the product is relatively high.

Chinese Patent Publication No.: CN101921001A introduces a method for recovering cobalt from cobalt sulfate solution, which first uses magnesium hydroxide slurry to carry out cobalt precipitation for the first time in a cobalt precipitation tank for cobalt sulfate solution, and the primary cobalt precipitation slurry obtained by the reaction After the primary cobalt precipitation buffer tank, 30-50% of the obtained pulp is returned to the primary cobalt precipitation tank, and the remaining pulp is subjected to pressure filtration, and the filter cake obtained by pressure filtration is the product, and the filtrate is subjected to secondary cobalt precipitation, which can effectively Avoid local over-alkali, but the slurry adjustment method increases the water consumption of the whole system

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