双层预烧结支撑工艺

Double-layer pre-sintering process with stand-support

为实现鞍钢本部高炉和烧结产能的匹配,提高烧结矿产量,并解决高比例精矿烧结时料层厚度难以超过900 mm的难题,鞍钢集团开发了双层预烧结工艺,但在实际生产过程中出现了烧结矿成品率下降、(5,10)mm准粉末级别烧结矿升高的问题,为此在实验室开展了1000 mm双层预烧结支撑工艺的基础研究。结果表明,双层预烧结时,在第二次点火后CO_(2)和CO体积分数升高,O_(2)体积分数急剧下降到8%左右,底部混合料层一定时间内为低氧气氛燃烧。双层预烧结时透气性指数变化分为3个过程,加入支架后,第1阶段平均提高10.37%,第2阶段平均提高12.61%,第3阶段中最低处平均提高28.95%;加入支架后,氧含量最低点时间提前,氧含量提高,烧结矿转鼓强度下降,但成品率上升,利用系数可以达到2.12 t/(m2·h),(5,10)mm的准粉末级别比例明显下降,350 mm支架较400 mm支架能取得更好的技术指标。支架烧结在实验室证明可以解决双层预烧结应用的关键难题,可以进一步释放其提产能力。

In order to match the blast furnace and sintering capacity of Anshan Steel,increase the sintering production and solve the problem that the thickness of sinter layer cannot exceed 900 mm with high-proportion concentrate,Anshan iron and steel group developed a double-layer pre-sintering process,however,the sintering yield decreased and the sintering with grade of(5,10)mm increased in the industrial production process.Therefore,the basic research on the 1000 mm double-layer pre-sintering process with stand-support was carried out in the laboratory.The results show that during the double-layer sintering,after the second ignition,the content of CO_(2)and CO are increased,the volume content of O_(2)is dropped sharply to about 8%,and the bottom mixture layer burns in a low-oxygen atmosphere for a certain period of time.The change of air permeability index during double-layer sintering can be divided into three processes.After adding the stand-support,the average index increases 10.37%and 12.61%of the first stage and the second stage,respectively,and the average index of the lowest point in the third stage increases 28.95%.After adding the stand-support,the time that at the lowest content of oxygen is advanced,and the content of oxygen is increased.Also,the sinter drum strength is decreased,but the yield of sinter is increased.The utilization coefficient can reach 2.12 t/(m2·h),and the quasi-fine ratio of(5,10)mm is reduced significantly.The stand-support of 350 mm can be obtained better technical index compared with the stand-support of 400 mm.Results in laboratory prove that,the stand-support sintering of double-layer process can solve the key problems in actual application and can release its production capacity further.