中文摘要：

研究了低品位碱预处理红土镍矿在混合酸介质中的加压浸出过程.褐铁型红土镍矿经碱预处理改性后,铁主要以非晶态铁氧化物形态存在,而镍主要以氧化镍形态吸附于非晶态铁氧化物表面.由实验确定的改性红土镍矿加压浸出优化工艺条件为：浸出温度458K、保温时间60min、浸出体系初始酸度2.44mol/L、液固比2mL/g、搅拌转速500r/min.上述工艺具有良好的稳定性,镍与钴浸出率分别保持在95%和80%左右,浸出渣含镍和钴分别低至约0.028%和0.007%,而杂质铁浸出率低至1%左右,有价金属镍、钴与杂质铁分离性能良好.经加压浸出,改性红土镍矿中的铁最终以赤铁矿形式水解沉淀入渣,且浸出渣含铁矿物中几乎不含镍,浸出渣中的铁可进一步回收利用.

英文摘要：

The pressure leaching of low grade alkali-pretreated limonitic laterite ore by a mixed acid was investigated.After alkali-pretreatment,iron exists in the form of amorphous iron oxide while nickel is adsorbed on the surface of iron oxides in the form of nickel oxide.The preferable pressure-leaching conditions of alkali-pretreated limonitic laterite ore are determined as follows：leaching temperature of 458 K,initial acidity of leaching system with cI=2.44 mol/L,leaching time of 60 min,ratio of liquid to solid of 2：1 mL/g,and agitation speed of 500 r/min.This pressure-leaching technique is proved to be effective and stable.Under the above conditions,the extraction rates of nickel and cobalt are kept about 95% and 80% respectively while that of iron is as lower as 1%.The content of nickel and cobalt in the leaching residues is as low as 0.028% and 0.007% respectively.The valuables of nickel and cobalt can be efficiently separated from the impurity of iron.After the pressure leaching of alkali-pretreated laterite ore,iron is finally hydrolyzed and precipitated in the form of hematite which can be further reclaimed.The iron minerals in the leaching residues rarely contain nickel.