链箅机-回转窑铬矿预还原球团工艺研究与应用

RESEARCH AND APPLICATION OF GRATE-ROTARY KILN CHROME PRE-REDUCTION PELLETIZING PROCESS

随着我国钢铁工业的快速发展,铬铁合金的需求量逐年增加,以铬球团矿代替粉矿入炉冶炼可提高高碳铬铁技术经济指标。当铬精矿和焦粉的比表面积为1 700 cm^2/g时,生球落下强度和抗压强度指标最好,爆裂温度为435℃。随着预热温度提高、预热时间延长,预热球团抗压强度增加,随着还原温度升高、还原时间延长,铬和铁的还原指标均呈增加趋势,在相同温度和时间下,铁比铬易还原。生产实践表明,预热球团抗压强度达500 N/P,铬预还原球团铬的还原度为55.98%,综合还原度为69.25%,矿热炉使用50%铬预还原球团热装配加50%冷烧结矿,铁合金日产量提高52 t、铬回收率提高3%,冶炼电耗降至2 600 k Wh/t,渣中铬含量降低2%。

With the rapid development of iron and steel industry in China,the demand of ferrochrome is increasing year by year.The technical and economic indicators of high carbon ferrochrome could be improved with chrome pellets instead of ore powder into the smelting furnace.When the specific surface area of chromium concentrates and coke powder were 1 700 cm 2/g,the drop strength and compressive strength of the green ball were the best,and the burst temperature was 435℃.With the increase of preheating temperature and preheating time,the compressive strength of the preheated pellets were increased.With the increase of reduction temperature and reduction time,the reduction indexes of chromium and iron were increased all.At the same temperature and time,the chromium was easier to be reduced than iron.The production practice showed,the compressive strength of preheated pellets attained 500 N/P,the reduction degree of pre-reduction pellets chromium achieved 55.98%,the comprehensive reduction degree obtained 69.25%.The 50%chromium pre-reduction pellets for hot assembly plus the 50%cold sinter ores were adopted in submerged arc furnace,the daily output of ferroalloy was increased 52 t,the recovery rate of Cr was increased 3%,the smelting power consumption was decreased to 2 600 kWh/t,the content of Cr in slag decreased 2%.