Rare earth ferrosilicon is a versatile alloy mainly used to control the detrimental effects of sulfur in steel and to modify graphite structures in cast iron. The aim of this study was to optimize the experimental conditions for the production of rare earth ferrosilicon alloy by using a preconcentrate prepared from a bastnasite type of ore present in the Beylikahir-EskiSehir region of Turkey. After unsuccessful initial tests realized with this preconcentrate, however, two batches of rich-rare earth oxide concentrates with different compositions, that were supplied from the Turkish glass producer SiSecam A.S. were utilized in order to investigate the effects of several variables like temperature, duration, amount of reducing agents etc. on the recovery of rare earth metals and the alloy compositions. The findings of these tests were then tested again on the bastnasite preconcentrate. There was no difficulty in obtaining rare earth ferrosilicon alloys containing 35-55 wt % rare earths, 25-40 wt % silicon and 5-25 wt % iron, with about 80 % rare earth metal recovery in the tests made with rich rare earth oxide concentrates, while alloys containing up to 44 wt % rare earths, with 48 % rare earth metal recovery could be produced with the bastnasite preconcentrate.

Rare earth ferrosilicon alloy is an important additive for ferrous metallurgy. It is mainly used to control the detrimental effects of sulfur in steel and to modify graphite structures in cast iron. The aim of this study was to optimize the conditions for the production of rare earth ferrosilicon alloy by metallothermic reduction process using a preconcentrate prepared from a bastnasite type of ore present in the Beylikahir-EskiSehir region of Turkey. In this study, the rare earth preconcentrate was reduced by aluminum together with ferrosilicon and rare earth ferrosilicon alloys were produced. The optimum conditions of reduction, which are time, temperature, reducer amounts and the basicity of the slag phase, were investigated by smelting in an induction furnace. At the end of the study, a rare earth ferrosilicon alloy containing 39.3 % rare earths, 37.5 % silicon, 19.3 % iron and 3.9 % aluminum was produced under the optimum conditions determined with 57.7 % rare earth metal recovery.