Arsenic Reduction Kinetics during Vacuum Carbothermal Reduction of Dust with High Content of Arsenic and Copper

In this study, arsenic removal was carried out via low-temperature vacuum carbothermal reduction method by utilizing dust containing higher content of arsenic and copper from pyrometallurgical refining furnaces of copper as raw materials. Effect of various factors such as reduction temperature, residual pressure, reductant dosage and time on the removal rate of arsenic was investigated and explored in detail. Arsenic reduction kinetics was analyzed and elaborated in detail on the basis of “shrinking-core model”. The results show that arsenic removal rate is enhanced with low reduction temperature and increasing amount of reduction dose, and decreasing residual pressure. Arsenic reduction removal is indicated to be controlled by ash diffusion. Apparent activation energy ~15.96 kJ/mol is determined for the reaction in the temperature range of 623–773 K. The kinetic equations for arsenic removal during vacuum carbothermal reduction can be described as 1 – 2a/3 – (1 – a)2/3 = 0.05774 exp[–1919.05/T]t.