Arsenic Condensation and Reaction Mechanisms in Flash Smelting Off-Gas Line Conditions

Arsenic is a common impurity element in sulfide concentrates. It tends to accumulate in the flue dust of smelting furnace due to the volatility and internal circulation of the flue dust practiced in the smelting-converting process chain. The only outlets for arsenic are anodes and discard slag. Arsenic condensation in dust-free conditions was studied below 800 °C where the gas atmosphere was controlled by SO₂-air-N₂ gas mixtures. Based on these experimental results, we confirm the kinetically constrained formation mechanism of the arsenic-containing dust, and its speciation into metallic, oxidic (III, V), and sulfidic species. The influences of temperature and atmosphere on the speciation of arsenic were compared with industrial data and discussed. Graphical Abstract: [Figure not available: see fulltext.]Condensed arsenic‐bearing particles collected by electrophoretic forces on the surface of fused SiO₂ in SO₂‐O₂ atmospheres: the crystal morphology shows euhedrally facetted As₂O₃ crystals and initially molten As‐OSalloy droplets together with poorly crystallized AsS _x particles.