Study On Reduction Roasting-magnetic Separation Treatment Technology Of Laterite Nickel Ore Rotary Kiln

Taking a laterite nickel mine in Indonesia as the research object,the thermodynamic conditions of red earth nickel ore reduction were analyzed by thermodynamic calculation,and a reasonable experimental scheme was developed to study the redox nickel ore rotary kiln reduction roasting magnetic separation process,and then establish the rotary kiln.The mathematical model is used to analyze the movement and heat transfer of laterite nickel ore pellets in the rotary kiln.Finally,the different factors affecting the temperature distribution of the laterite nickel ore pellets in the kiln are analyzed.Through research,the following conclusions are drawn:(1)Thermodynamic analysis of reduction of laterite nickel ore shows that,theoretically,the reduction temperature of laterite nickel ore is between 675 ° C and 737 ° C to ensure the reduction of nickel oxide in the laterite nickel ore to metal nickel and iron oxide to form a stable oxidation.Ferrous iron,but it is difficult to achieve this ideal condition in the actual calcination reduction process.Therefore,it is necessary to explore the effect of reasonable reduction roasting process conditions on the reduction roasting-magnetic separation of this type of laterite nickel ore.(2)Through experiments,the optimal parameters for the reduction roasting-magnetic separation of this type of laterite nickel ore are as follows: calcination temperature is 1180 °C,roasting time is 90 min,carbon content is 1.4,grinding time is 90 min,magnetic separation current 2.5A,the amount of calcium chloride additive is 12%.(3)The analysis of the movement of laterite nickel ore pellets in the rotary kiln shows that the laterite nickel ore pellets are most beneficial to the reduction and roasting of laterite nickel ore during the rolling motion in the rotary kiln,which is established by mass conservation and momentum conservation.The relevant moving differential equations are solved and solved,and the relationship between the kiln diameter and the range of the rotational speed is analyzed.(4)The rotary kiln was designed on the condition that the annual treatment of laterite nickel ore was 120,000 tons,and the parameters of the rotary kiln were optimized.The speed was determined to be 1.5r/min,the inclination was 1.5%,and when the kiln length was 65 m,the total residence time was about 116 min,and the moving speed of the pellet in the axial direction of the kiln was 0.56m/min.(5)The heat transfer analysis in the rotary kiln shows that the one-dimensional axial heat transfer model in the rotary kiln can effectively and intuitively describe the temperature distribution of the flue gas,pellets and kiln inner wall in the rotary kiln,and optimize the design of the rotary kiln.Provide a reliable basis,and finally determine the maximum kiln length of the rotary kiln is 70 m.