Phase transformation in reductive roasting of laterite ore with microwave heating

• Published in: Transactions of Nonferrous Metals Society of China Vol. 18; no. 4; pp. 969 - 973
• Main Author: 畅永锋 翟秀静 符岩 马林芝 李斌川 张廷安
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2008; School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China
• Subjects: carbothermic reduction; laterite; microwave; 微波加热; 还原煅烧; 铁矾土矿石; laterite; carbothermic reduction; microwave
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(08)60167-3

Selective reduction of laterite ores followed by acid leaching is a promising method to recover nickel and cobalt metal, leaving leaching residue as a suitable iron resource. The phase transformation in reduction process with microwave heating was investigated by XRD and the reduction degree of iron was analyzed by chemical method. The results show that the laterite samples mixed with active carbon couple well with microwave and the temperature can reach approximate 1000 ℃ in 6.5 min. The reduction degree of iron is controlled by both the reductive agent content and the microwave heating time, and the reduction follows Fe2O3→Fe3O4→FeO→Fe sequence. Sulphuric acid leaching test reveals that the recoveries of nickel and iron increase with the iron reduction degree. By properly controlling the reduction degree of iron at 60% around, the nickel recovery can reach about 90% and iron recovery is less than 30%.