废弃物中重金属元素在水泥熟料形成过程中的作用及其固化机理

EFFECT AND INCORPORATION MECHANISM OF HEAVY METAL ELEMENTS IN HAZARDORS INDUSTRIAL WASTES DURING CLINKER FORMATION

利用水泥窑处理危险工业废弃物已经成为全球水泥行业发展的趋势。介绍了实验室模拟水泥窑焚烧处理含重金属元素的危险工业废弃物的研究,旨在探讨废弃物中重金属元素在水泥熟料形成过程中的作用及其固化机理。结果表明:对于所研究的8种重金属元素(Cr,Co,Ni,Cu,Cd,Pb,Zn,As),实验用工业生料中绝大部分重金属元素含量不超过西欧和美国标准。在实验用工业生料基础上掺入含有重金属元素的危险工业废弃物,可以改善生料的易烧性,尤其是较低温度(1350℃)下的易烧性。焚烧含重金属元素的危险工业废弃物时,水泥熟料的早期强度降低而后期强度略有提高。水泥熟料矿物可以固化绝大部分重金属元素,熟料矿物对重金属元素的固化具有选择性。

There is a development trend around the world for cement industry to recycle hazardous industrial wastes (HIW) by using cement rotary kiln. A simulation test for burning the HIW under laboratory conditions as cement sintering process was studied with the aim of exploring effect and incorporation mechanism of heavy metal elements from the HIW in clinker forming process and 8 different kinds of heavy metal elements′ (Cr, Co,Ni, Cu, Cd, Pb, Zn, As) incorporation mechanism in the clinker during the process. Results show that contents of the most for the 8 heavy metal elements contained in the simulation test of industrial raw meal were within the limits of both the European criterion and the American standard. The burning ability of the raw meal doped with the heavy metal elements are improved, especially when the temperature is below 1 350 ℃. It is found that the 3 d strength of the clinker made from the raw materials mixed with the HIW decreases while the 28 d strength increases slightly.Most of the heavy metal elements can be incorporated in the sintered clinker phases although the incorporation has element selectivity, which depends on the variety of clinker phases.