Experimental Study On The Production Of Iron-nickel Concentrate By Reducing Roasting-magnetic Separation Of Laterite Nickel Ore

Along with the increasing depletion of nickel sulfide ore and the increasing demand for nickel in industrial development,how to develop laterite nickel ore economically and efficiently is of great significance to the national economic development.The mainstream technology of processing laterite nickel ore today,rotary kiln dry pre-reduction-electric furnace smelting method and blast furnace method,although after years of development,there are still problems such as the high energy consumption that cannot be ignored.The use of rotary kiln reduction roasting-magnetic separation process to treat laterite nickel ore is more energy efficient and environmentally friendly in comparison.In this thesis,theoretical and experimental studies were conducted on laterite nickel ore produced in Indonesia,and the influencing factors of of roasting and magnetic separation processes were analyzed,and the results of this work can provide reference for actual production.In this thesis,firstly,the experimental study on the reduction roasting of laterite nickel ore was carried out by designing orthogonal tests to investigate the effects of carbon allocation,roasting temperature,roasting time,and other factors on the experimental reduction effect.The better process parameters were obtained: internal carbon C/O=0.9;roasting temperature at 1250°C;roasting time at 90 min.The results showed that the order of influence on the Ni grade in the magnetized material was:roasting temperature ? roasting time > carbon content;the order of influence on the Ni recovery in the magnetized material is: roasting temperature > carbon content >roasting time;the order of influence on the yield of the magnetized material is: roasting temperature >> carbon content ? roasting time.The effects of magnetic separation method,grinding time,and magnetic field intensity on the magnetic separation effect were studied by magnetic separation experiments.The results indicated that the better magnetic separation method was slow feeding and secondary magnetic separation,and the magnetic field intensity was 940 Gauss at each magnetic separation;the grinding time had an effect on the magnetic separation effect,and the recommended grinding time was 90 min.In the range of magnetic field intensity studied,the magnetic field intensity had a small effect on the magnetic separation effect.Under the proposed roasting process parameters and magnetic separation conditions,for the experimental raw materials,i.e.,Ni content about 1.5%,the parameters of the magnetic material obtained after reduction roasting-magnetic separation as follows: the recovery of Ni was greater than 85%;the grade of Ni in the magnetic material was about 4.5%;and the yield of the magnetic material was about 32%.Based on the experiments,the material balance and heat balance of the rotary kiln were calculated to obtain the natural gas unit consumption,flue gas volume,composition of the rotary kiln roasting,which provided the required parameters for the rotary kiln design.Combined with the material balance and heat balance of the rotary kiln,the selection calculation of the rotary kiln for roasting was carried out,and the effective inner diameter and rotational speed of rotary kiln were determined.The residence time of material in the selected rotary kiln was about 146 min,and the residence time in the high temperature roasting area was about 90 min,which could meet the roasting requirements of the recommended working conditions of the roasting process.