Experimental Study On The Effects Of Alkali On Sintering Strength And Coke Properties

With the development of the steel industry,the influence of the alkali elements on the sintering strength and the coke has become the key in the iron and steel field,and the control of the alkali contents and the kinds of the alkali elements in the smelting process of the blast furnace is increased,so that the final production benefit can be improved and the social development requirement is in line with the requirements of the social development.From that practical view of the production of the blast furnace,the occurrence of the alkaline harm of the blast furnace is frequent,the influence is serious,the specific gravity of the harmful alkali elements in the sinter is the largest,and the influence of the alkali elements in the sintering process is analyzed,and the alkali elements balance in the sintering process is calculated by calculating the influence of the alkali elements in the sintering process,the alkali elements content in the raw material of the furnace can be obtained,the alkali elements accumulation rate and the alkali discharge rate of the blast furnace are further known,a suitable raw fuel of the furnace is selected,the alkali load of the blast furnace can be effectively reduced,and the sintering strength is ensured to meet the production requirement of the blast furnace.On this basis,the effect of alkali elements on the metallurgical properties of coke was explored.The main conclusions of the paper are as follows:(1)For hematite,with the increase of K2O contents,the compressive strength of hematite decreases,the content of K2O increases from 0%to 4%,and the compressive strength of hematite decreases from 5000 N to 2864 N.(2)For calcium ferrite,with the increase of K2O contents,the compressive strength of calcium ferrite decreases,the contents of K2O increases from 0%to 4%,and the compressive strength of calcium ferrite decreases from 3066 N to 680 N.(3)Under the condition of the same K2O contents,the strength of hematite is higher than that of calcium ferrite.(4)With the increase of dust removal ash ratio,the sinter drum strength decreases,the dust removal ash ratio increases from 0%to 3.23%,and the sinter drum strength decreases from 61.07%to 75.47%.It is suggested that the amount of dust removal ash in the sinter mixture should be controlled by the steel mill.(5)With the increase of coke alkali leaching amount,CRI increases obviously.CSR was different from the traditional point of view.With the increase of K2O contents,CSR decreased and increased.The essential reason is determined by the restrictive link of coke dissolution reaction.For coke with good quality,the dissolution reaction process is controlled by"internal diffusion".The higher the alkali elements contents,the stronger the damage to the internal structure of coke and the worse the strength CSR.For the coke with poor quality,the dissolution reaction process is controlled by the "interface reaction".The higher the alkali elements contents,the higher the coke responsiveness,but the reaction mainly occurs on the surface,the damage to the internal structure is small,and the strength will not become worse.(6)The method comprises the following steps of:a)reducing alkali elements load,b)regularly discharging alkali,c)reducing the proportion of dust-removing ash in the sintering material,and the like,The specific effect is as follows:1)The coal ratio of 1#and 2#BF is remarkably improved when the fuel ratio of the three blast furnaces of the A-steel is not large.The 1#blast furnace is increased from 135.11kg/tHM of the reference period(the average value of 2017)to 174.97 kg/tHM of the application period(the average value of 2019),and the 2#blast furnace is increased from 119.93 kg/tHM to 157.11 kg/tHM.The coal-to-coal ratio of 3#BF has been higher,which is basically stable at 150 kg/tHM?160 kg/tHM;2)the coke ratio of the three blast furnaces of A-steel is significantly reduced:1#blast furnace is reduced from 379.00 kg/tHM of the reference period(average of 2017)to 346.63 kg/tHM of the application period(the average value of 2019),and the 2#blast furnace is reduced from 363.76 kg/tHM to 339.96 kg/tHM,3#BF is reduced from 354.04 kg/tHM to 344.83 kg/tHM;3)the coal ratio of the three blast furnace of A-steel is increased,and the economic benefit brought by the reduction of coke ratio is significant.