The preparation of ferronickel alloy from the nickel laterite ore with low Co and high MgO contents was studied by using a pre-reduction-smelting method. The effects of reduction time, calcination temperature, quantity of reductant and calcium oxide (CaO), and pellet diameter on the reduction ratio of Fe and on the pellet strength were investigated. The results show that, for a roasting temperature > 800 A degrees C, a roasting time > 30 min, 1.5wt% added anthracite coal, 5wt% added CaO, and a pellet size of similar to 10 mm, the reduction ratio of Fe exceeds 70% and the compressive strength of the pellets exceeds 10 kg per pellet. Reduction smelting experiments were performed by varying the smelting time, temperature, quantity of reductant and CaO, and reduction ratio of Fe in the pellets. Optimal conditions for the reduction smelting process are as follows: smelting time, 30-45 min; smelting temperature, 1550A degrees C; quantity of reductant, 4wt%-5wt%; and quantity of CaO, 5wt%; leading to an Fe reduction ratio of 75% in the pellets. In addition, the mineral composition of the raw ore and that during the reduction process were investigated by process mineralogy.
在较低温度下采用硫酸低温熟化—水浸工艺处理褐铁型红土镍矿,对熟化—水浸渣进行矿物学表征,并对熟化过程动力学进行了研究。结果表明,红土镍矿经过熟化—水浸处理,矿物的矿相发生转变:铁由针铁矿相转变为赤铁矿等铁的氧化物,大部分镍钴矿物转变为硫酸镍和硫酸钴,小部分转变为难溶的铁酸镍和铁酸钴造成镍和钴的损失。硫酸熟化过程动力学研究表明,镍钴硫酸化动力学过程符合典型的多相液固区域反应动力学模型,镍钴硫酸熟化反应表观活化能分别为12.4 k J/mol和3.2 k J/mol,这一过程受内扩散控制。
