An alternative route to extract nickel and cobalt from non-commercial laterite ore

Abstract Laterite ores, which represent around two-thirds of nickel reserves, became an important source of nickel and cobalt metals. The objective of the present study was to investigate the efficiency of a hybrid route to extract nickel and cobalt present in a laterite ore sample which was not commercially attractive to be processed through the current routes. The process efficiency was investigated through the application of different test conditions, such as roast temperature, ore sample comminution, and moisture. Chemical analysis by atomic absorption was used to quantify the metals. The solid phase’s identification and characterization were accomplished by X-ray diffraction and Scanning Electron Microscopy. The Rietveld Method was used for the mineral’s phase quantification. In terms of nickel and cobalt extractions, the most favorable condition was: particle size smaller than 38 µm, 50% sulfuric acid (wt.%), and 10% moisture (wt.%), which permitted nickel, cobalt, magnesium, and iron recoveries of 84.5%, 92.0%, and 93.0%, 27.0% respectively. These results indicate the successful application of the route. In addition, it was found that chlorite, chromite, hematite, and goethite were identified as the main nickel and cobalt carriers present in the process residue.

摘要 红土矿（Laterite Ores）约占全球镍储量的三分之二，现已成为镍、钴金属的重要来源。本研究旨在探究一种混合工艺路线的提取效率，该路线用于处理某一采用现有工艺加工不具备商业经济性的红土矿样品，从中提取镍与钴。通过调控焙烧温度、矿石磨矿粒度与物料含水率等多项试验条件，对该工艺的效率开展探究。采用原子吸收光谱分析法对样品中的金属含量进行定量测定。采用X射线衍射（X-ray Diffraction）与扫描电子显微镜（Scanning Electron Microscopy）完成了固相物相的鉴定与表征，并采用里特维尔德法（Rietveld Method）开展矿物相的定量分析。在镍、钴提取效果方面，最优工艺条件为：物料粒度小于38 μm、硫酸质量分数50%、物料含水率10%（质量分数），在此条件下镍、钴、镁、铁的回收率分别为84.5%、92.0%、93.0%与27.0%。上述结果证实该混合工艺路线应用成功。此外，研究发现工艺残余产物中的主要镍、钴载体矿物为绿泥石、铬铁矿、赤铁矿与针铁矿。