Kinetics study of leaching arsenic from Ni-Mo ore roasting in dust mixture of hydrochloric and sulfuric acids

摘要

The kinetics of leaching arsenic from Ni-Mo ore roasting dust was investigated.The effects including leaching temperature,particle size of the smelter dust,stirring speed,the coefficient β(the molar ratio of sodium chlorate to arsenic in the smelter dust)and the initial H+ concentration on leaching arsenic were studied.The results indicate that the leaching of arsenic increases sharply with the decrease of particle size.The orders of reaction with respect to H+ concentration and particle size are determinted to be 1.136 and-1.806,respectively.The leaching of arsenic reaches 99% under experimental conditions,the apparent activation energy is determined to be 11.157 kJ/mol,which is consistent with the values of activation energy for diffusion model.The kinetics equation of leaching arsenic from the roasting dust could be expressed by a semi-empirical equation as 1-2/3η-(1-η)2/3=k0(c[H+])1.136 r0-1.806 exp[(-11157/RT)t].