城市污水厂剩余活性污泥生产生态水泥

引言 随着我国对城市生活污水处理能力以及污水处理率的不断提高,污水处理厂的污泥产量也不断增长.由于其产量较大,含水率高,同时含有大量有机质、病菌、寄生虫和重金属等1-2],如果处理处置不当,会给环境带来严重的二次污染.

Wastewater treatment plant activated sludge for production of eco-cement

The effect on the cement property by using sewage sludge as an additive in the process of clinker burning was investigated.Based on the standard sample P.O42.5 from the cement plant, the properties of eco-cement samples with the addition of sewage sludge 0%,5.0%，10.0% and 15.0% per unit raw material were compared under the calcining heat of 1250℃，1350℃ and 1450℃ respectively.The results of the analysis particle size determination, X-ray diffraction, SEM, hydration characters of the clinkers, as well as the compressive strength of the cement mortar showed that the temperature for the formation of liquid phase decreased with the improving burnability of raw material.Moreover, the concentration of f-CaO obviously decreased with the increase of sewage sludge ratio.However, the content of C₃S crystals in all clinker decreased, whereas the content of C₂S crystals increased with the increase of sewage sludge ratio.The microstructure of the clinker was observed to be porous at the temperature of 1450℃ and the sewage sludge ratio 15.0%.Additionally, the hydration of the clinker decreased, and its relative compressive strength of 3 d and 7 d decreased with the increase of sewage sludge ratio, but it was increased at latter ages.