Effects of Borax and Grinding Alkalinity on the Reduction–Magnetic Separation of Beach Placer

Abstract

The effect of borax on the reduction characteristics of Indonesia beach placers was investigated. The effect of grinding alkalinity on the magnetic separation of the reduced sample was also studied in this paper. The mineral phase transformation, microstructures of reduction, and magnetic separation products were analyzed to reveal the enhanced separation mechanism of titanium and iron in beach placer. The borax could effectively improve the metallization rate and the growth of iron grains in a reduced sample. When 3% borax was added to the reduction process, the metallization rate of the reduced beach placer reached 95.64%, and the metal iron grains grew to about 50 μm. Adjusting the grinding alkalinity could prevent the metallic iron from being oxidized and promote the monomer dissociation between mineral particles. The iron powder concentrates with 94.07% total Fe and vanadium-rich titanium slag with 36.32% Ti were obtained by grinding magnetic separation as the grinding alkalinity pH was 13.

Keywords

• beach placer
• borax
• enhanced reduction
• mill alkalinity
• metallization rate