Chapter 17 - Smelting of Nickel Sulfide Concentrates by Roasting and Electric Furnace Smelting

Abstract

This chapter discusses production of nickel matte suitable for refining to high-purity nickel from nickel sulfide concentrates. The first process is smelting the concentrates and subsequently converting them suitably. Smelting process produces nickel rich matte. There are two industrial methods used for smelting nickel sulfides. One is roasting followed by smelting in an electric furnace and the other method is flash smelting. The objectives of this chapter are to describe the principles involved in the roasting and smelting of nickel sulfide concentrates and industrial practice of fluidized–bed roasting and electric furnace smelting. Though roasting and smelting methods results in high recovery of nickel, copper, cobalt and by-product precious methods, there is a large consumption of electricity and hence only 25% of industries use this process. Flash smelting process is largely used due to its lesser consumption of electricity. The advantages of electric smelting are, of course, its ability to attain and control high slag temperatures, which is very important as the calcine feed contains large amount of MgO which has a high melting point and also its efficiency in smelting metal—rich scrap and other by-products.