Research On Strengthening Sintering Production By Quicklime

At present in China,sinter plays an important role in blast furnace burden structure.In 2018,sinter accounts for more than 70%of the total blast furnace burden in Shagang.During the sintering process,the selection and use system of flux has a great influence on output,quality and economic benefits.Shagang has achieved good results through improving sintering flux use system from 2017 to 2018.This study is divided into three parts:1)By sintering pot experiment and ore phase composition,study the influence of burnt lime ratio and particle size on various indexes of sinter.2)Explore the influence of mixture moisture and digestion time on sinter technical and economic indicators.3)Analysis the economic benefit of burnt lime use system to sintering cost and blast furnace hot metal cost.Mainly by sintering cup experiment,industrial production,technical and economic analysis,this thesis systematically studied the sintering burnt lime use system to provide technical support and theoretical basis for Shagang to improve sinter quality,increase output and reduce blast furnace ironmaking cost.The conclusion is as follows:1)Effects of burnt lime proportion on sinter output and quality?When the proportion of burnt lime increased from 3.0%to 4.5%,the utilization coefficient increased greatly.When the proportion continued to increase,the utilization coefficient increased slowly or even decreased.? As the proportion of burnt lime increased,the drum strength increased first and then decreased,and the inflection point is at the proportion of burnt lime is 4.0?4.5%;?The proportion of burnt lime increased from 3%to 5.5%,the utilization coefficient(the output)increased by 9.5%,the solid fuel consumption decreased by 2.37kg/t,the finished product ratio increased by 1.5%,the sinter average particle size increased by 2.63mm,and the amount of 5-40mm finished ore increased by 1.8%.2)Effects of mixture moisture and digestion time on sintering process,output and quality.? The particle size of+3 mm increased by 1.4%for every 0.1%increase in water content on average.The utilization coefficient increased with the increase of water content,but when the water content was greater than 7.5%,the growth rate slowed down.? The drum strength decreased with the increase of water content,and the burnup increased with the increase of water content,but the tow changes are slow.?Water use coefficient is positively correlated with fuel consumption and negatively correlated with drum strength.?When the digestion time was 5?7 min,the utilization coefficient,fuel consumption and drum strength are all at a good level.After the digestion and mixing of burnt lime,with the decrease of burnt lime particle size distribution range,the increase amplitude of mixture temperature becomes greater ? With the decrease of burnt lime particle size,the proportion of>3mm in the mixture increased.? When burnt lime the size fraction distribute in1?3 mm,the utilization coefficient is the maximum.The drum strength,fuel consumption and particle size distribution of finished ore have no obvious change with burnt lime size distribution changes.3)Effect of burnt lime use system on production technical and economic indexWhen the proportion of burnt lime in Shagang is 4.2-4.5%,all the performance index reach the relative optimal value.By the proportion of burnt lime increased from 3.5%to 4.5%,the utilization coefficient(output)increased by 3.3%,the fuel consumption decreased by 1.19 kg/t,the grade change increased by 0.07 and the strength of finished drum increased by 0.02%.Therefore,increasing the proportion of burnt lime can increase the yield and reduce the fuel consumption.