Preparation of stainless steel master alloy by direct smelting reduction of Fe–Ni–Cr Sinter at 1600°C

Abstract

Feasibility analysis and experimental studies for the production of a stainless steel master alloy by direct smelting reduction have been investigated in this work, showing that the master alloy with proper compositions and satisfactory metal recoveries can be obtained at 1600°C. When the temperature was increased from 1450 to 1600°C, the grades for Fe, Ni and Cr increased from 50.04, 1.1 and 13.36% up to 73.39, 1.77 and 16.42%, respectively. Experiments were then carried out focusing on the influence of various fluxes on the reduction behaviour, showing that CaO resulted in the increase in the recoveries of Fe, Ni and Cr, SiO₂ improved the recoveries of Fe and Ni, but did not favour the recovery of Cr because of an increase of CrO and Cr₂O₃ within the slag. MgO was not effective as a flux because of the formation of spinel. This increased the effective viscosity of the slag because of the presence of suspended solids, and led to a poor separation between the alloy and slag.