高品位赤铁矿带式焙烧机制备气基直接还原用氧化球团技术

Technology of gas-based direct reduction of oxidized pellets with high grade hematite concentrates by travel grate process

钢铁行业是典型的高耗能、高排放行业。近些年来,中国钢铁行业发展迅猛,目前已经是世界上最大的钢铁生产国和消费国。相比于烧结,球团工艺对环境更为友好。在双碳背景下,发展直接还原工艺是钢铁行业碳减排的重要举措。以高品位赤铁矿为研究对象,研究碱度、配碳量、黏结剂种类和用量以及热工制度等因素对生球和成品球团质量的影响,开发高品位赤铁矿气基直接还原用氧化球团技术。结果表明,以该高品位赤铁矿为原料制备的球团,在相同的热工制度以及黏结剂用量下,相比膨润土和丙烯酰胺(PAM),F黏结剂作为球团黏结剂的效果是更优的,在碱度为自然碱度的条件下即可获得抗压强度大于2500 N/P的成品球团,而以膨润土和丙烯酰胺(PAM)为黏结剂制备球团,则需要碱度大于0.3才能获得满足生产标准的成品球团;该高品位赤铁矿以F黏结剂、膨润土和丙烯酰胺(PAM)为黏结剂制备球团,提高碱度都能改善球团的焙烧性能,提高成品球团的抗压强度;一定范围内,配加兰炭可提高以该高品位赤铁矿所制备的球团的焙烧性能;该高品位赤铁矿以PAM为黏结剂,在最佳条件下可获得铁品位达到68.22%、(SiO_(2)+Al_(2)O_(3))质量分数小于2%、抗压强度大于2500 N/P、冶金性能良好的成品球团,可作为优质的气基直接还原用氧化球团原料。

Iron and steel industry is a typical intensively consuming-energy and CO_(2) emission industry.China’s iron and steel industry has grown rapidly in recent decades,with China now the world's largest producer and consumer of iron and steel.Compared with iron sintering,pelleting process is more friendly environmentally with lower energy consumption and less co2 emissions.Development of direct reduction iron-making processes is important initiatives under the Background of Carbon Emission Peak and Carbon Neutrality.High grade hematite as the research object is taken to study the effect of basicity,blue charcoal dosage,binder type and dosage,thermal engineering system,etc.on the quality of green pellets and fired pellets with pure hematite concentrates by travel grate process.The experiment results show that compared to bentonite and Polyacrylamide(PAM),F-binder is superior to improve the quality of pellets,with high grade hematite as raw material.The fired pellets prepared from high grade hematite’s compressive strength beyond 2500 N/P with natural basicity and F binder,while the fired pellets prepared with bentonite and PAM require a basicity greater than 0.3 to meet the production standard.Whether F binder,bentonite or PAM as binder for the production of high grade hematite pellets,the firing performance and compressive strength of fired pellets can be improved by increasing the basicity.In a certain range,the firing properties of the pellets prepared from high grade hematite can be improved by adding blue charoal.The fired pellets prepared form high grade hematite and with PAM as binder,under the optimal conditions,it can be revealed that iron grade of the fired pellets is as high as 68.22%,and the mass percent of(SiO_(2)+Al2O3)is blow 2%,and the compressive strength is over 2500 N/P,and possess satisfactory metallurgical performance,which can meet the requirement of gas-based direct reduction process.