中文摘要：

对低铁、高硅、高镁腐殖土型红土镍矿的脱水和碳还原过程进行DTA-TG分析,确定脱水和固体碳还原反应的温度区间。在煅烧-还原熔炼红土镍矿制备镍铁中,针对矿石自然渣型碱度低、黏度及密度大,不利于金属与渣分离及镍回收率提高等问题,采用控制CaO加入量的方法,调节CaO-FeO-MgO-SiO2系炉渣的黏度和密度;探讨还原剂焦粉及CaO用量、温度、时间对熔炼效果的影响。综合考虑镍铁品位和镍的回收率,确定最佳还原熔炼试验条件：焦粉、石灰与矿石质量比分别为9.0%和8.3%,温度为1 550℃,时间为40 min。在最佳试验条件下,产出的镍铁品位为22.0%,镍、钴回收率分别为92.5%和70.0%。

英文摘要：

The dehydration and carbon reduction processes of a humus type laterite ore with high silicon and magnesium,low iron contents were analyzed by DTA-TG method,thereby the temperature ranges were determined in which the reactions of dehydration and carbon reduction of the ore took place.In the reduction smelting process of producing ferronickel from the laterite ore,the causes of difficulty of separating ferronickel from slag and lower nickel recovery,was presented i.e.low basicity,high velocity and density of the inherent slag constitution of the ore,which were solved through regulating CaO additive amount to obtain a appropriate constitution of the CaO-FeO-MgO-SiO2 slag system.The effects of additive amounts of reductant coke and CaO,temperature and time on smelting results were discussed individually.According to the experimental results,the optimal conditions of the reduction smelting are determined by considering the ferronickel grade and nickel recovery comprehensively as follows： mass ratio of coke to ore 9.0%,mass ratio of CaO to ore 8.3%,temperature 1 550 ℃ and time 40 min..In the conditions,the ferronickel grade is 22%,recoveries of nickel and cobalt are 92.5% and 70.0%,respectively.