As pyrometallurgical technologies to smelt nickel metal from the oxide ore, melting reduction process using an electric furnace (Elkem) and semi-melting reduction process using a rotary kiln (Krupp-Renn) with a saprolite ore as a raw material have been established and operated commercially. However, in the future, it is expected that it will be difficult to smelt nickel from the oxide ore because of the decline of nickel grade in the ore and it is necessary to develop a new process adaptable to lower grade ore and difficult processing ore.
The authors have conducted fundamental research on the pyrometallurgical reaction of low grade and difficult processing nickel oxide ore smelting by the rotary hearth furnace (RHF). Liquefied gas burner will be supposed from points of cost, reduction of global warming gas and so on in the operation of Ni smelting. On the other hand, it is getting clearer that Fe and Ni metallization degree in liquefied gas burning atmosphere are lower than those in N2 atmosphere. The reason have been guessed effects of H2O generating in liquefied gas combustion. The results about effects of H2O to reduction reaction of low Nickel grade oxide ore is described in this report.
