Experimental Study On The Coal-based Direct Reduction Preparing Ferro-nickel Alloy From Humus Laterite Nickel Ore

In recent years,the demand for nickel resource has been rising due to the development of China's steel industry.For a long time,the acquisition of nickel raw materials in China has been dominated by nickel sulfide.However,because of the long-term exploitation of nickel sulfide ore,reserves have fallen sharply.Therefore,research and development of laterite nickel ore resources is very necessary.Laterite nickel ore is mainly divided into limonite type and humus type.The former is mostly treated by high-pressure acid leaching and other hydrometallurgy processes.The latter,which is low-iron and high-nickel,mainly manufactured by the reduction and smelting of electric furnace.Due to the serious pollution of the wet metallurgical process environment and the high energy consumption of the thermometallurgy process,this paper uses a laterite nickel mine in Indonesia as the raw material to carry out the experimental study on the preparation of nickel-iron alloy by coal-based direct reduction of humus-type laterite nickel ore.The coal-based direct reduction process:the advantages and disadvantages of the rotary kiln iron method and the rotary blast furnace has been studied.The thermodynamic calculation software FactSage was used to carry out the thermodynamic analysis of the laterite nickel ore during carbon reduction,and the reduction temperature and reduction of the rotary kiln method were investigated.The effects of time,carbon ratio and CaO addition on the reduction of Ni and Fe in laterite nickel ore,and the reduction of the iron-reducing temperature,reduction time,grinding time and magnetic field in the laterite nickel ore.The influence of Ni and Fe reduction process indicators has the following conclusions:(1)Thermodynamic analysis shows that the composite phases of nickel and iron present in the carbothermal reduction process of laterite nickel ore are 2FeO·SiO2(fayalite),2NiO·SiO2(nickel silicate),MgO · SiO2(ececuliar),2MgO·2Al2O3·5SiO2(cordierite),the order of reduction of iron and nickel phases is Fe2O3,NiO,2NiO·SiO2,Fe3O4,FeO,2FeO·SiO2;(2)The transition order of the iron-containing phase in the reduction process is(Mg,Fe)3(Si,Al)3O7(OH)4/FeOOH/Fe2O3?Fe2O3?Fe3O4?2FeO·SiO2?Fe;and the transformation of nickel-containing phase The history is:Ni3Si2O5(OH)4/(Ni,Mg)3Si2O5(OH)4?NiO·SiO2?Ni;(3)The process parameters determined by the rotary kiln method are reduction temperature 1350?,reduction time 2 h,carbon ratio 1.2,CaO addition amount 10%,iron and nickel content in the magnetic material are 77.32%and 7.90%,respectively;and the recovery rates of iron and nickel were 95.87%and 89.36%,respectively;(4)The process parameters determined by the rotary hearth method are magnetic field strength 100mT,grinding time 2 min,reduction temperature 1350?,reduction time 0.5h,carbon ratio 1.2,CaO addition amount 10%;under this condition,The content of iron and nickel is 74.36%and 7.78%,respectively;the recovery rates of iron and nickel are 91.45%and 92.15%,respectively;(5)Comparing the treatment processes of two low-grade laterite nickel ores,it shows that the rotary kiln process has low energy consumption and large nickel-iron alloy particles,while the rotary hearth furnace has a short smelting cycle,simple operation and high production efficiency.