How to Extract Cobalt and Tungsten from Waste Cemented Carbide

With the rapid development of economy, the demand for tungsten and cobalt in machinery manufacturing, geology, mining, construction, electronics and chemical industries is increasing. As rare metal elements, tungsten and cobalt are also the main raw materials of cemented carbide. Therefore, it is very meaningful to recycle tungsten and cobalt from scrap cemented carbide.

At present, the process of extracting cobalt and tungsten from scrap cemented carbides includes separating cobalt and tungsten from the recycled cemented carbides by classifying, crushing, ball milling and electrolysis powder, and then by chemical extraction. Due to the high hardness of waste cemented carbide, powder can be obtained directly by crushing and ball milling. Its efficiency is low. Generally, a production cycle is at least 20 days. In addition, the electrolysis of waste cemented carbide still has potential dangers of high energy consumption and environmental pollution. Some scholars have reformed the recovery process of cemented carbide to achieve a better recovery scheme of tungsten and cobalt, which includes the following steps:

1, simmering
Burning waste cemented carbide at a temperature of 1700‐1750 °C;

2, broken
The calcined cemented carbide block is placed in a ball mill for ball milling and crushing;

3, screening and separation
The cemented carbide crushed by the ball mill is sieved and separated, and the separated large cemented carbide is returned to the ball mill for ball milling and crushing;

4, extraction of cobalt and tungsten

The cemented carbide powder obtained by crushing the ball mill is reacted with a sodium hydroxide solution, and the obtained sodium tungstate solution is added with sulfuric acid, and ammonia water is extracted and stripped to form an ammonium tungstate solution, which is heated, evaporated, crystallized, dried, and again. The simmering is added with hydrogen to reduce to metal tungsten powder. Finally, the solid matter is extracted with cobalt sulfate and ammonium oxalate to extract cobalt powder and nickel powder, and metal ruthenium.

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