EXPERIMENTAL STUDY ON REDUCTION ROASTING-SULFURIC ACID LEACHING OF LATERITE-NICKEL ORE

A typical limonitic laterite ore contains 1. 04% nickel and 40. 55% iron,grade of magnesium and silica is relatively low. Particle size of the ore is very fine,fraction of less than 0. 038 mm accounted for 66. 58%. Nickel mainly embeds in limonite and silicate minerals,the distribution rate being 75% and 24. 04% respectively. Reduction roasting and sulfuric acid leaching method was adopted to deal with the ore. The results showed that under the condition of carbon particle size 90%-0. 074 mm,carbon dosage 30%,roasting temperature 700 ℃,roasting time 30 min,sulfuric acid dosage 0. 5 m L / g,leaching temperature 80 ℃,leaching time 2. 0 h,liquid and solid ratio 5∶ 1,the leaching rate of Ni,Co and Fe was 74. 88%,93. 83% and 35. 87% respectively.