Hydrothermal sulfidation of hemimorphite with elemental sulfur

Direct flotation of zinc oxide ore is characterized by poor recovery of only around 50% of zinc. Hydrothermal sulfidation of hemimorphite with elemental sulfur resulted in the formation of stable metal sulfide compounds that would enhance zinc recovery by flotation process. The variables considered in the study were sulfur dosage, temperature, time, stirring speed and particle size. Temperature was the most important factor. The experimental data indicated that under the hydrothermal conditions with sulfur dosage 1.2, temperature 220 degrees C, time 180 mm, agitation speed 500rpm and particle size74-106 mu m, and 73% hemimorphite conversion fraction was achieved.