分流预成型强化制粒改善镜铁矿粉烧结性能

Improving the sintering performance of specularite bearing mixtures by separated pre-agglomeration-sintering processes

  • 摘要: 针对镜铁矿精粉成球性及可烧性差的特点,采用分流预成型强化制粒工艺对进口镜铁矿精粉制粒及烧结性能开展研究.与常规制粒工艺烧结指标相比,采用分流造球强化制粒烧结工艺,焦粉配比从4.85%降至4.20%,利用系数从1.44 t·m-2·h-1提高至1.71 t·m-2·h-1,转鼓强度从57.60%提高至63.80%,固体燃耗从76.46 kg·t-1降至65.24 kg·t-1;采用分流辊压预成型强化制粒烧结工艺,焦粉配加量从4.85%降至4.70%,利用系数从1.44 t·m-2·h-1提高至1.64 t·m-2·h-1,转鼓强度及固体燃耗基本不变.因此,分流预成型强化制粒工艺较常规制粒工艺能显著改善镜铁矿烧结性能.其作用机理为:镜铁精矿经分流预成型后能改善混合料的透气性,降低焦粉配比,提高烧结料层氧位,生成更多的铁酸钙及赤铁矿,所得成品烧结矿结晶完善,矿物之间胶结紧密,内部气孔由不规则大孔变为总体分布较为均匀且大小适中的规则球形,改善了烧结矿的强度和还原性.

     

    Abstract: For the characteristics of weak ballability and inferior amenability of specularite concentrates, the granulating and sintering performances of imported specularite were investigated by two kinds of separated pre-agglomeration-sintering processes. Compared with the traditional granulation-sintering process, the separated micropelletizing-granulation-sintering process presents competitive results:decreasing the coke level from 4.85% to 4.20%, improving the productivity from 1.44 t·m-2·h-1 to 1.71 t·m-2·h-1, enhancing the tumble index from 57.60% to 63.80%, and cutting the solid fuel rate from 76.46 kg·t-1 to 65.24 kg·t-1. In the meantime, the separated pre-briquetting-granulation-sintering process also shows better results:decreasing the coke dosage from 4.85% to 4.70%, elevating the productivity from 1.44 t·m-2·h-1 to 1.64 t·m-2·h-1, and keeping the tumble index and the solid fuel rate steady. Overall, the separated pre-agglomeration-granulation-sintering process can significantly improve the sintering performance of specularite. The mechanism of action is that the separated pre-agglomeration-granulation-sintering process improves the permeability of the mixture markedly, decreases the coke dosage appropriately, results in a higher oxidation potential in the sintering bed, and produces more calcium ferrite and hematite finally. Meanwhile, mineral crystals in the product sinter grow perfectly and compactly, and the pores mainly develop into middle or small sized spheres from the irregular big ones, all of which contribute to the higher strength and better reducibility of the product sinter.

     

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