Enhanced Separation of Sulfur and Metals from Polymetallic Sulfur Slag through Recrystallizing Regulation of Sulfur Crystals

Abstract

Elemental sulfur is an important non-metallic material that is widely used in various fields including chemical, metallurgical and sulfuric acid industries. Polymetallic sulfur slag (PSS) is an important secondary resource for the recovery of sulfur. However, separation of sulfur from PSS is difficult due to the tight binding of some thiophilic metals to sulfur. Herein, we proposed a recrystallization method for the effective separation of sulfur and metals by using organic solvents to control the particle size of sulfur crystals. It was suggested that the particle size of sulfur recovered in the close to saturation state of toluene is about 2000 μm, while the purity is as high as 99.6%. Moreover, the recovery rate is over 95%, which is more than the current commonly used flotation method. The growth mechanism of sulfur crystals under different saturation conditions lays a foundation for the deepening of the growth theory of large-size sulfur crystals. This method realized the effective separation of sulfur from metal sulfides such as FeS2 and ZnS, which provided an important guidance for the recovery of sulfur resources through a novel method of recrystallizing regulation.