Dynamics of ultrasound-assisted oxidation leaching of nickel sulfide concentrate

The method of leaching nickel directly with oxidants of sulphate and silver salts with the assistance of ultrasonic was proposed.The influence of stirring speed,S2O82-concentration,leaching temperature,silver ion concentration and granularity on the leaching rate of nickel was investigated.The reaction mechanism of oxidizing leaching was explored.The results show that the influence of stirring speed or granularity on the leaching rate is not obvious in a certain range;with the increase of S2O82-concentration or leaching temperature,the leaching rate of nickel increases,whereas when the temperature is above 70 ℃,the increase of leaching rate is not obvious;S2O82-plays a dominant role in the oxidation action during the leaching process.The presence of a small amount of silver salt can promote the leaching reaction.Through investigating the dynamic parameters of the process,the dynamics in accordance with the shrinking core model is found.The overall reaction rate is controlled by interfacial chemical reaction with apparent activation energy of 39.67 kJ/mol.The macro-dynamic equations of the process are established.