煤灰残碳对氧化球团回转窑结圈物形成的影响  

Effect of residual carbon in coal ash on formation of ring accretion of rotary pelletizing kiln

作　　者：范建军[1] 郭宇峰[2] 臧龙[3] 王磊[3] 

机构地区：[1]太原钢铁(集团)有限公司技术中心,山西太原030003 [2]中南大学资源加工与生物工程学院,湖南长沙410083 [3]太原钢铁(集团)有限公司岚县矿业公司,山西吕梁035504

出　　处：《中国冶金》2017年第12期8-13,共6页China Metallurgy

摘　　要：为了解链箅机-回转窑氧化球团生产过程中回转窑内的结圈物的形成机理,首先采用X射线衍射、显微镜以及扫描电镜能谱对结圈物进行分析检测,发现其矿物组成主要为赤铁矿及硅酸盐相;然后进行含残碳煤灰和球团矿粉末的模拟焙烧试验,为进一步验证FeO对低熔点物质生成的作用,利用FactSage软件中的Phase Diagram模块,计算绘制液相投影图。结果表明,试样在高温过程中其FeO质量分数可达到10%~20%,而FeO可与煤灰中的SiO_2、CaO、Al_2O_3等生成含亚铁相的硅铝酸盐类低熔点化合物;当FeO质量分数从5%到30%依次升高时,SiO_2-CaO-Al_2O_3-FeO四元系相图中的液相区不断扩大,且液相线温度由1 200降低至1 100℃;FeO的存在对低熔点化合物的产生有较大的促进作用,证实喷煤补热燃烧过程中,含残碳煤灰与球团粉末混合后,可生成含亚铁相的硅铝酸盐类低熔点化合物,导致结圈物的形成。In order to study the mechanism of formation of ring accretion of rotary pelletizing kiln in the production of oxidized pellet by grate-kiln process,the XRD,microscope and SEM image and EDS were first applied in the analysis and detection of the ring.The results showed that the main mineral compositions were hematite and other silicate solids.Then the roasting experiments were performed with coal ash and pellet fines as raw material,the results indicated that the mass fraction of FeO can reach 10%-20%,and the FeO can react with the SiO_2,CaO and Al_2O_3 in coal ash to form the low-melting-point compounds.In order to verify the effect of FeO on the low-melting-point compounds,the Phase Diagram in FactSage was used to calculate the liquidus isotherms of ternary system SiO_2-CaO-Al2O_3.The results indicated that the low temperature liquidus isotherms for quaternary system SiO_2-CaO-Al_2O_3-FeO would extend gradually with the increase of FeO mass fraction from 5% to 30% and the liquidus temperature decreased from 1 200 to 1 100℃.Finally,it is indicated that the presence of FeO definitely promoted the formation of the low-melting-point compounds.And it is confirmed that during the coal injection process for heating and burning,after mixing the coal ash containing the residual carbon with the pelletizing powder,the low-meltingpoint aluminosilicate compounds containing ferrous were formed,which caused the formation of ring accretion in rotary kiln.

关 键 词：链箅机-回转窑 球团 煤粉 结渣物 残碳 三元相图 

分 类 号：TF046.6[冶金工程—冶金物理化学]