Extractive Metallurgy and Recycling of Cobalt

Cobalt is a vital metal in the modern society because of its applications in lithium-ion batteries, super alloys, hard metals, and catalysts. Further, cobalt is a representative rare metal and is the 30th most abundant element in the Earth's crust. This study reviews the current status of cobalt extraction and recycling processes, along with the trends in its production amount and use. Although cobalt occurs in a wide range of minerals, such as oxides and sulfides of copper and nickel ores, the amounts of cobalt in the minerals are too low to be extracted economically. The Democratic Republic of Congo (DRC) leads cobalt mining, and accounts for 68.9 % of the global cobalt reserves (142,000 tons in 2020). Cobalt is mainly extracted from copper-cobalt and nickel-cobalt concentrates and is occasionally extracted directly from the ore itself by hydro-, pyro-, and electro-metallurgical processes. These smelting methods are essential for developing new recycling processes to extract cobalt from secondary resources. Cobalt is mainly recycled from lithium-ion batteries, spent catalysts, and cobalt alloys. The recycling methods for cobalt also depend on the type of secondary cobalt resource. Major recycling methods from secondary resources are applied in pyro- and hydrometallurgical processes.

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