Leaching Kinetics of Antimony from Refractory Gold Ore in Alkaline Sodium Sulfide under Ultrasound

Abstract

The leaching kinetics of antimony from refractory gold ore in alkaline sodium sulfide was investigated under ultrasound. The influence of factors such as stirring speed, temperature, the concentration of sodium hydroxide and sodium sulfide and particle size, was studied. The leaching kinetics has also been studied under convention and ultrasound. The experimental data are consistent with the shrinkage core model and the leaching rate is controlled by surface chemical reaction for both ultrasonic and the conventional method. Ultrasound increases the leaching rate of antimony from 81.2% to 93.1%. It can be seen that the rate constant kr of ultrasonic method at various temperatures is larger than that of the conventional method. The ultrasound reduces the apparent activation energy from 48.39kJ/mol to 33.88kJ/mol and reduces the apparent response series of sodium sulfide concentration from1.3 to 1.1. Comparing with conventional method, the ultrasound can greatly improve the antimony leaching rate, accelerate the leaching process and lower temperature and the concentration of sodium hydroxide and sodium sulfide. These advantages of ultrasonic method were also confirmed by the SEM analysis of the leached solid.