Arsenic Condensation and Reaction Mechan

Arsenic is a common impurity element in sulfide concentrates, leading to its accumulation in the flue dust of smelting furnaces due to volatility and internal circulation. This study investigates arsenic condensation in dust-free conditions below 800 °C using controlled SO2-air-N2 gas mixtures to understand its reaction mechanisms and speciation. Experimental results confirm the kinetically constrained formation mechanism of arsenic-containing dust, characterized by its transformation into metallic, oxidic (III, V), and sulfidic species. The influence of temperature and atmosphere on arsenic speciation was analyzed and compared with industrial data. Condensed arsenic-bearing particles, collected using electrophoretic forces on fused SiO2 surfaces in SO2-O2 atmospheres, displayed euhedral As2O5 crystals, molten As-O-S droplets, and poorly crystallized AsxSx particles. Additional analyses, including X-ray diffraction and scanning electron microscopy, identified the phases and compositions of these arsenic compounds across different temperature ranges and highlighted the significant chemical reactions between the As-bearing gas stream and sulfur and oxygen agents during nucleation. The study provides insights into the behavior of arsenic in smelting processes and offers potential avenues for improving the management of arsenic emissions in metallurgical operations.