The copper ore mined is primarily surface-oxidized copper-cobalt polymetallic ore. Therefore, hydrometallurgical processes are predominantly used for copper extraction. The typical hydrometallurgical process for copper involves "ore leaching (heap leaching or agitation leaching) – solvent extraction – electrowinning." During copper leaching, cobalt is usually extracted using reducing agents such as sulfur dioxide or sodium sulfite. Both copper and cobalt are recovered from the sulfuric acid solution containing these metals and then electrowon to produce cathode copper. Most cobalt products from industrial operations are crude cobalt compounds obtained through simple impurity removal in the aforementioned process. The most common crude cobalt compound is cobalt carbonate, produced via sodium carbonate precipitation of cobalt.

However, crude cobalt carbonate has a relatively low cobalt content, typically around 25%, which increases transportation and other associated costs. Additionally, the cobalt solution after sodium carbonate precipitation contains a significant amount of difficult-to-treat sodium salts. Direct discharge of this solution causes environmental pollution, while long-term recycling within the system leads to excessive sodium ion buildup, severely affecting copper production. With increasingly stringent environmental regulations, many companies have begun researching more economical and environmentally friendly cobalt production processes. The Magnesium Oxide cobalt precipitation process has proven to be an effective solution to this problem.

Practical applications demonstrate that by neutralizing and removing impurities from the cobalt-bearing copper raffinate, the optimal conditions for cobalt precipitation with magnesium oxide are achieved at a final pH of 8.0, using a magnesium oxide slurry. This method yields cobalt hydroxide with a grade exceeding 36%, a cobalt recovery rate above 99%, and a magnesium oxide utilization rate of 91%.

Cobalt recovery from cobalt sulfate solution is typically achieved by adding magnesium oxide slurry to produce cobalt hydroxide. The stability of magnesium oxide slurry concentration is crucial for product quality in industrial cobalt production. A higher slurry concentration increases magnesium impurities in the cobalt product, negatively impacting quality, while a lower concentration reduces cobalt recovery efficiency.

 Magnesia/Magnesium oxide (MgO)/Light magnesium oxide/Heavy magnesium oxide/Reactive magnesium oxide