Development and Assimilation of Technology of Obtaining Electrolytic Cobalt from Industrial Products

At Norilsk Mining and Metallurgical plant up to now electrolytic cobalt K-0 has been obtained from commodity cobalt hydroxide. This hydroxide was dissolved in hydrochloric acid and was purified from Fe, Cu, and Ni by extraction with sodium salts of synthetic monocarboxylic acids.

A new technology has been developed to use the industrial product of the main cobalt production, i.e., the solution after purification from manganese, instead of commodity hydroxide. This solution contains sulphate and chloride ions. For obtaining electrolytic cobalt from this solution it is necessary to convert the sulphates to chlorides. This is conducted by extraction of cobalt (and heavy metals impurities) with sodium salts of SMA and then by stripping with hydrochloric acid. This procedure allows obtaining the concentrated cobalt chloride solutions and separate light metals. After the conversion the obtained solution is purified from copper by extraction with the cobalt salt of SMA and from nickel by extraction with a mixture of non-chelating aldoximes and SMA. This mixture of extractants provides an effective purification of cobalt solutions. The separation coefficient pN/c is 25-30.

Use of this technology at the Norilsk Mining and Metallurgical plant has allowed the reduction of the reagent expenses and improved the purification from nickel. In addition extraction equipment has been decreased more than two times at the same productivity. The suggested procedure of conversion allows the use of solutions of practically any anion composition for obtaining cobalt.