Optimization Of Nickel Laterite Sintering Process And The Enhancement Of Granulation By Blending

In recent years,with the depletion of nickel sulfide ore resources and the continuous growth of stainless steel demand,abundant and cheap nickel laterite has been widely used in stainless steel production.Among them,the limonite nickel laterite is mainly produced by sintering-blast furnace process.However,in the production of nickel laterite sintering,there are often problems such as low strength of sinter,low yield,high fuel consumption,and inadequate mixing of the mixture,poor pelleting performance,etc.,which seriously affect the benefit of stainless steel enterprises.Therefore,it is necessary to optimize the sintering process of nickel laterite and strengthen the study of blending granulation.In this paper,the process optimization was carried out by adjusting the parameters such as basicity,anthracite ratio,water content,anthracite grain size and layer distribution mode.The mixing effect was strengthened by using strong mixer.By adjusting parameters such as wetting time,cylinder mixer speed,pelleting time and separated granulation process,the granulation performance was strengthened,and the following conclusions were drawn:（1）The process optimization study showed that under the optimized process parameters of basicity 1.6,anthracite ratio 7.2%,water 18.5%,anthracite particle size1-5 mm,under the layered and graded distribution style,Compared with the reference,the amount of liquid phase in the sintering process increases and the high-temperature time is prolonged,which promotes the consolidation of sinter and is conducive to the sintering process.Thus the tumbler index increased by 19.82%and utilization coefficient increased by 0.10t·m^-2·h^-1.（2）Enhanced blending research shows that:After using the powerful mixer,the degree of blending is greatly improved;and the granulation performance of the secondary mixture was improved obviously.The proportion of+3mm particles in the mixture was increased from 54.78%to 91.81%,the average particle size was increased from 4.18mm to 4.74mm,and the air permeability index was increased from 0.233 to0.457.The improvement of granulation performance is beneficial to increase sintering rate and oxygen potential of material layer,thus improving sintering performance.Thus the utilization coefficient increased by 0.12t·m^-2·h^-1,and the solid fuel consumption decreased to 12.63kg·t^-1.（3）Enhanced granulating research shows that:（1）The optimized granulating parameters were wetting time 9 min,cylinder mixer speed 24 r/min and granulating time 10 min.Under the conventional distribution method,the air permeability index increased from 0.233 to 0.385,tumbler index increased by 5.07%,utilization coefficient increased by 0.07 t·m^-2·h^-1,solid fuel consumption decreased by 3.42 kg·t^-1.Under the layered and graded distribution style,the air permeability index increased from 0.281 to0.418,drum strength increased by 5.23%,utilization coefficient increased by0.17t·m^-2·h^-1,solid fuel consumption decreased by 4.12kg·t^-1.（2）After fractional pelleting,air permeability index increased from 0.233 to 0.482,drum strength increased by 9.09%,utilization coefficient increased by 0.22 t·m^-2·h^-1,solid fuel consumption decreased by 16.81 kg·t^-1.