Method for recycling sludge of sewage plant to produce cement

Abstract

The invention relates to a method which is used for directly applying the settled sludge of a wastewater treatment plant to the cement production after treatments of iron removing, sterilization and deodorization, dehydration and drying. The method comprises the following steps: firstly, the iron of the sludge is removed; secondly, the sludge is sterilized and deodorized; thirdly, the sludge is dehydrated and dried; fourthly, the mixture amount of the sludge is determined; fifthly, the sludge enters a kiln system for calcining; and sixthly, the clinker obtained by the incineration and gypsum are mixed and made into cement by a cement grinding mill. The method adopting the invention has the following advantages: firstly, the resource utilization of the sludge is realized, a large amount of clay mineral is economized, and the precious land resource is saved; secondly, the abundant heat value of the sludge can be effectively utilized, and the coal resource can be economized; thirdly, the harmless treatment is carried out to the sludge at the temperature higher than 1450 DEG C, both the organic matters and the inorganic matters in the municipal sludge can be cracked and calcined into harmless matters, and the possibilities of producing poisonous gases and waste residues are avoided during the low temperature treating process; fourthly, the heavy metals in the municipal sludge are dissolved in the portland cement clinker minerals in a solid way, and are tightly combined with the cement ingredients by chemical bonds, and the heavy metal pollution phenomenon cannot happen under the usual conditions; and fifthly, the mixed and burnt sludge does not increase the clinker calcination difficulty and does not reduce the cement strength, but also has a certain mineralization promoting effect on the cement clinker calcination to a certain extent.

Description

technical field [0001] The invention relates to a method for producing cement by using sewage plant sludge as one of raw materials to replace part of clay after being sterilized, deodorized, dehydrated and dried. Background technique [0002] Sludge refers to the sediment produced in the sewage treatment process of the sewage plant. The stench and microorganisms emitted by the sludge are fatal to the environment. At present, the main treatment methods of sludge are landfill, composting and incineration. The landfill and composting methods have the disadvantages of large land occupation, long treatment cycle, and easy to cause secondary pollution. The incineration method is relatively thorough in treating sludge, but there are also disadvantages: (1) Due to the high water content and low calorific value of sludge, it is generally necessary to add additional fuel, which increases unnecessary expenses; (2) sludge In the process of incineration, dioxin-like highly toxic substa...

AI Technical Summary

Problems solved by technology

The landfill method and composting method have the disadvantages of large area, long treatment cycle, and easy to cause secondary pollution.

The incineration method is relatively thorough in treating sludge, but there are also disadvantages: (1) Due to the high water content of sludge and low calorific value, it is generally necessary to add additional fuel, which increases unnecessary expenses; (2) sludge In the process of incineration, dioxin-like highly toxic substances will be produced, and the investment in the purification system is relatively large, and the operating cost is high

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