污泥对水泥熟料烧成和强度的影响

Effect of Sludge on Formation and Strength of Cement Clinker

利用污水处理厂污泥替代硅质原料配制多组水泥生料,污泥掺量变化范围0-10%,生料KH（石灰饱和系数）变化范围为0.88-0.97,在1400℃下煅烧,测定各熟料的f-CaO和强度,并结合XRD,SEM/EDS等分析,研究污泥掺量及生料KH对水泥熟料烧成和强度性能的影响。另外还对掺10%污泥所烧制的熟料进行了重金属溶出试验。结果表明,在生料KH保持0.94而污泥掺量变化的情况,污泥掺量在2.5%左右时对改善生料的易烧性和熟料强度均有利,而污泥超过这个掺量后,生料易烧性和熟料强度随污泥掺量增加而明显降低;在污泥掺量保持2.5%而KH变化的情况下,KH小于0.91时,掺入污泥对生料易烧性和熟料强度不利,而KH大于0.94时,污泥掺入能改善生料易烧性,对熟料强度也略有提高;即使水泥生料中污泥掺量高达10%,所烧制的水泥其重金属滤出值远远小于标准的规定值,不会对环境产生危害。从水泥生料易烧性、熟料强度和重金属溶出试验看,只要生料配比合理和污泥掺量合适,污泥可以在水泥生产中得到无害化处置和资源化利用。

Cements raw meals contained different amounts of sludge of 0 to 10% and with KH（lime saturation coefficient） of 0.88-0.97 were calcined at 1400℃.The effect of sludge from sewage plant on the formation and properties of cement clinkers was investigated by free lime content and mortar strength determination,and XRD,SEM/EDS analysis.Besides,the heavy metals leaching of the clinker with 10% sludge was also tested.The results indicate that： when KH is fixed at 0.94 2.5wt.% sludge gives the optimum strength and best calcining characteristics, but while the sludge content is above that, sludge is harmful; when the sludge content is 2.5wt. ~ ,while KH is under 0.91, sludge is harmful for sintering and strength, while KH is above 0.94 the addition is beneficial; the leaching value is under the standard. According to the sintering for raw meal, the clinker strength and the heavy metals leaching test, as long as the mixture ratio of the raw meal and the sludge content are appropriate, it＇s feasible to replace part of the raw materials for cement production by sludge from Sibao Sewage Plant in Hangzhou.