Ferronickel is mainly produced in submerged-arc furnaces by reducing lateritic nickel ores. The process aims to transfer most of the nickel into the metal phase. It starts with pre-heated and pre-reduced ores which are hot charged as calcine (at temperatures of up to 800 °C) into the furnace. Then the final nickel reduction takes place in the submerged-arc furnace. Usually, round furnaces are used for smaller and medium quantities, whereas large capacities are produced in rectangular furnaces. Nickel contents of up to 35 % in the FeNi are possible.
Today, advanced high-power FeNi-smelting furnaces are very efficient and implement a series of improvements such as various sidewall cooling methods as well as AC thyristor controls. These ensure better operation, higher and more efficient power input, and less overall maintenance.
The world's largest submerged-arc furnace for FeNi was recently supplied to POSCO SNNC, a joint venture between the Korean company POSCO and the mining company SMSP, which is based in New Caledonia. The power rating of the rectangular FeNi smelter is 135 MVA, resulting in a total nominal effective power input of 100 MW. The large-capacity furnace comes with impressive dimensions of 40x15x8.5 m, making it the world's largest electric smelter. SMS group was proud to work with such a high-reputation partner on this project. Finallly, in January 2015, the first metal was tapped, and 100% capacity load was already demonstrated in 2015. This project exemplifies our superior position in FeNi smelters.