回转窑处理钢铁厂含锌粉尘结圈机制的研究

Study on the Mechanism of Ring Forming in Rotary Kiln of Zn-Bearing Dusts from Ironmaking and Steelmaking Process

针对回转窑处理含锌粉尘过程中的结圈问题,采用XRF、SEM和EDS等测试方法对窑中结圈物的化学组成和矿相组成进行分析,研究了窑中结圈物的形成机理。结果表明,结圈物的最主要的化学成分是铁和铁的氧化物,CaO、SiO2、Al2O3的含量也相对较高。内层结圈物以铁的浮氏体、钙长石为主,内层结圈以固相固结为主,液相粘结为辅。中层结圈物中液相的含量很高,铁的浮氏体和黄长石、尖晶石类物质次之。中层结圈主要是液相粘结造成的。粘结相主要是橄榄石类液相和铝酸盐类液相。外层结圈物以液相、铁的浮氏体和硅酸钙为主,主要是液相粘结,粘结相主要是金属铁液相和硅酸盐液相。导致结圈最主要的原因是煤灰的堆积和物料中各种氧化物反应形成的低熔点化合物在窑中高温的作用下形成了液相,在此基础上,提出了抑制窑内结圈的措施。

The study focuses on ring formation of rotary kiln in the process of treating Zn-bearing dusts from ironmaking and steelmaking process. The chemical composition and phase composition of the ring were analyzed using XRF, SEM and EDS. The results show that the ring consists of iron and iron oxides, and have relative high contents of CaO, SiO2, and Al2O3. The internal layer is mainly composed of iron wustite and calciclase, and mainly caused by solid phase sintering, complemented liquid phase bonding. The middle layer contains much liquid phase, and some iron wustite, the melilite and the spinel. The outer layer is mainly composed of liquid phase, iron wustite and calcium silicate. It is mainly caused by liquid phase bonding. The bond phase is predominantly liquid metallic iron and silicate liquid phase with low melting point. Based on the above results, proposing the following formation mechanism of ring: the accumulation of coal ash and the various oxides in the material form a low melting point compounds in the kiln, in turn the liquid and solid particle form high viscosity fluids adhere to the wall of rotary kiln. On the basis of the results, the measures to suppress the knot in the kiln are put forward.