Extraction of nickel and cobalt from laterite using a microwave assisted hydrothermal leaching method

A microwave assisted hydrothermal leaching method was used to extract nickel and cobalt from saprolite laterite. The effects of roasting pretreatment, leaching temperature and time on the extraction ratios of nickel and cobalt were investigated in detail. The extraction ratio of 93. 65% for nickel and 87. 86% for cobalt can be obtained respectively when the leaching temperature and time are 50℃ and 1 h for saprolite laterite only pre-roasted at 300℃. Comparing the microwave assisted hydrothermal leaching method with a hydrothermal leaching method, nickel and cobalt can be extracted more efficiently from the laterite. The experimental data indicate that the leaching process of nickel and cobalt is a diffusion-controlled process.