Nickel sulphide smelting and electrorefining practice: A review

Nickel in the form of cathodes, rounds, powders, and salts is well recognized as a useful commodity in domestic industries and/or export. It is shipped as concentrates, mixed sulphides, and ferronickel. Today, there are only a limited number of major and minor producers of this important metal, which is employed worldwide in a multitude of commercial and residential applications. Traditionally, nickel and associated metal values are recovered from ore feedstock by proven mineral processing, smelting, and refining processes. Typical host minerals contain other base metals, such as copper, cobalt, and noble metals consisting of gold, silver, and OPMs (otherprecious metals). Although sulphide-bearing ores such as those found in Canada and Russia will likely serve as a long-term source of this nonferrous material, the future trend is expected to involve laterite processing, which represents about 70% of the world's known nickel resources. The authors are aware of seven nickel refineries (ie, electrorefining) on a global basis dedicated to the production of class I primary nickel products. The supply and demand of pure and high-grade nickel products during the past decade has been erratic and subject to wide fluctuations in delivered price. This article describes theestablished industrial processes for recovery of nickel originating from sulphidic sources. Details of smelting and refining practice are provided for the three largest nickel producers. For completeness, other extractionprocesses involving a mixed sulphide, pellets from the carbonyl process, nickel powders, and briquettes are noted in the compendium of nickel processing practice, which includes pyrometallurgical principles. This paper lists the 47 pyrometallurgical operations worldwide which are mainly dedicated to the production of class II nickel products (nickel oxide products and utility nickel), nickel matte, and granules. The theme of the nickel biography is to provide a full extractive metallurgy synopsis rather than the reader reviewing numerous authors.