To the question of pyrometallurgical technology for processing antimony-gold-bearing ores and concentrates

Abstract

The increasing demand for non-ferrous, precious, and rare metals necessitates more comprehensive and efficient use of mineral raw materials, such as gold-antimony ores and concentrates. A promising approach is the use of pyrometallurgical processing in a fluidized bed, which offers more efficient heat and mass transfer than conventional technologies. This study aims to investigate the evaporation kinetics of antimony sulfide (Sb₂S₃) from gold-antimony ores and concentrates in a fluidized bed under various conditions. The experiments involved varying temperature (923-1223 K), particle size (0.09-2.0 mm), and layer thickness (5-15 mm) to determine the evaporation rate of Sb₂S₃. The experimental setup consisted of a laboratory-scale fluidized bed reactor equipped with a controlled gas flow of nitrogen mixed with sulfur vapor. The evaporation rates were measured using a gravimetric method and confirmed by X-ray diffraction and microscopic analysis of samples. The results show that the evaporation rate of Sb₂S₃ in a fluidized bed is 7-9 times higher than in a fixed bed. This is due to significantly improved heat and mass transfer in the fluidized system. At 1023 K, the overall evaporation rate increased with decreasing grain size. This is associated with an increase in the total surface area of the material, but the specific evaporation rate normalized to unit surface area was independent of particle size. The process was not significantly affected by bed height in the range of 5-15 mm. Antimony recovery into sublimates improved by 2-3% compared to conventional technology. It reached 98-99% due to suppression of Sb₂O₅ formation. These findings confirm the efficiency of supplying an inert gas with sulfur vapors into the fluidized bed. This reduces harmful gas emissions and minimizes dust entrainment. It also allows for effective distillation of volatile components at lower temperatures.