利用废弃物煅烧水泥时重金属Pb、Cd的逸放污染

利用废弃物作为代替原料煅烧水泥已广泛应用于水泥生产,但其带来的环境污染问题不容忽视。以利用废弃物生产水泥的厂家为研究对象,采用原子吸收分光光度法检测所采集样品中重金属Pb、Cd的含量,对水泥生产过程中重金属Pb、Cd的逸放及其对周围土壤的污染进行研究。研究结果表明:利用废弃物煅烧水泥的过程中,重金属Pb、Cd的逸放率很高,其中立窑的Pb、Cd逸放率高达84%～90%,湿法回转窑的Pb、Cd逸放率达到63%～74%;在水泥厂上下风向500m、1000m和2000m处采集土壤样品,工厂周围的土壤均已受到不同程度的重金属污染,位于工厂下风向的土壤受到的污染更为严重,距离工厂500m处土壤中重金属Pb、Cd的含量均超过了国家标准的最大限量;对几家工厂员工的头发进行随机取样,头发样品中Pb含量均超过正常限量。

Emission pollution of heavy metals Pb and Cd during cement calcinations by utilizing waste materials

Waste materials were utilized as raw materials during cement production widely, and the problem of environmental pollution must be noticed. The cement plants which utilizing waste materials were investigated, the emission pollution of heavy metals Pb, Cd and the soil pollution around cement plants during cement production were discussed in this article. The contents of Pb and Cd were detected by means of atomic absorption spectroscopy (AAS). The emission rates of Pb and Cd during cement calcinations were very high. The emission rates of Pb and Cd in shaft kiln were in the range from 84 % to 90 %, and those in wet process rotary kiln were in the range from 63 % to 74 %. Soil samples were collected from 500 meters, 1 000 meters, 2 000 meters upwind and downwind from cement plants. Soil around the cement plants was polluted by the emitted heavy metals Pb and Cd during cement calcinations, and the contents of Pb and Cd of soil samples 500 meters away from the plants all exceeded the maximum limit. The contents of Pb in hair samples collected from workers of cement plants all exceeded the normal limit.