Method for producing cement expansive material by using flying ash, desulfurized gypsum from incineration of refuse

Abstract

The invention discloses a method for preparing a concrete expansion agent by utilizing MSWI (municipal solid waste incineration) fly ash and desulfurization gypsum, which comprises the two steps of: (1) adopting the MSWI fly ash, the desulfurization gypsum, limestone, and bauxite as raw materials to obtain sulphoaluminate clinker through temperature increase and thermal insulation in an electric furnace; and (2) cogrinding the sulphoaluminate clinker and the desulfurization gypsum to obtain the concrete expansion agent. In the step (1), the raw materials are heated to be between 1,200 and 1,250 DEG C in the electric furnace according to the temperature-rising speed of between 20 and 30 DEG C / min, and then the sulphoaluminate clinker is obtained after the thermal insulation for 1 to 2h; and in the step (2), the sulphoaluminate clinker and the desulfurization gypsum are coground until the specific surface area is more than 250m / kg. The method comprehensively utilizes solid wastes such as the MSWI fly ash and the desulfurization gypsum to completely substitute natural gypsum and partially substitute non-renewable mineral resources such as the limestone, the bauxite and the like; and the method can lighten the serious burden to the environment and the treatment cost due to the unuse of fly ash and the desulfurization gypsum when ensuring the performance of products, and has good economic and social benefits.

Description

technical field [0001] The invention belongs to the fields of new material technology and environmental protection technology, and relates to the utilization of solid waste such as garbage incineration fly ash and desulfurized gypsum and the technology for producing concrete expansion agent. Background technique [0002] Concrete expansion agent refers to an admixture that can cause a certain volume expansion of concrete due to chemical action during the hardening process after being mixed into concrete. Concrete crack prevention is a major technical problem that the concrete engineering field has been committed to solving for a long time, and the shrinkage compensation effect of the expansion agent is the most commonly used method to control concrete cracks in engineering. [0003] Concrete expansion agent is widely used, mainly used in shrinkage compensation concrete, expansion concrete for filling, grouting materials and self-stressing concrete. Concrete expansion agent ...

AI Technical Summary

Problems solved by technology

However, the consequence of this limestone-gypsum wet desulfurization process is that a large amount of desulfurized gypsum is piled up and decomposed to cause secondary pollution, which is harmful to climate, soil, plants and human health

In addition, the by-product gypsum in the production process of many chemical companies has long been a problem

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