Method for eliminating alkali foaming expansion of MSWI bottom ash-high temperature calcination melting method

Abstract

The invention provides a method for eliminating alkali foaming expansion of MSWI bottom ash-high temperature calcination melting method, in particular to a preparation method applied to an MSWI bottomash alkali excitation material. According to the method, an MSWI bottom ash raw material is calcined into a molten state to damage protective film (aluminium oxide) of residual elemental aluminum inMSWI bottom ash, so that the elemental aluminum is converted into the aluminium oxide, thereby completely eliminating the phenomenon of alkali foaming expansion of the MSWI bottom ash; high-temperature calcination removes residual organic matters and unburned substances in the MSWI bottom ash, thereby significantly enhancing the polymerization activity of the MSWI bottom ash and achieving the preparation of the high-strength MSWI bottom ash alkali excitation material. An MSWI bottom ash alkali-excited test piece prepared by the high-temperature calcination melting method has the characteristics that the compressive strength reaches 39.4 MPa after being maintained for 3 days, reaches 60.7 MPa after being maintained for 28 days and exceeds the strength of PO 52.5-grade cement mortar, therebybeing completely suitable for being used in engineering as a structural material. The MSWI bottom ash alkali excitation material serves as a novel binding material, can partially replace cement, notonly can eliminate the environmental pollution problem caused by massive accumulation of the MSWI bottom ash, but also can alleviate the excessive dependence on Portland cement and reduce the excessive consumption of non-renewable resources, thereby being of great significance to China with a shortage of energy and serious environmental pollution.

Description

technical field [0001] The invention relates to a method for eliminating the foaming and expansion of MWI bottom ash in contact with alkali. The method can completely eliminate the deformation of the alkali-excited test piece caused by the foaming and expansion of MWI bottom ash in contact with alkali, and remarkably improves the polymerization reaction activity of MWI bottom ash. Preparation of high-strength MWI bottom ash-alkali-excited materials. Background technique [0002] The products after municipal solid waste incineration are mainly divided into two categories: one is fly ash, which accounts for about 20% of the total ash. Because fly ash contains a lot of heavy metals and highly toxic pollutants, so Fly ash is a strictly controlled solid waste in my country. The other type is bottom ash, which accounts for about 80% of the total amount of ash. Bottom ash is usually collected at the bottom of the combustion boiler and is mainly composed of different types of large...

AI Technical Summary

Problems solved by technology

The results show that MSWI bottom ash undergoes serious foaming and expansion when it encounters alkali, which leads to expansion and deformation of the test piece stimulated by alkali, resulting in fatal defects and failure to build strength. Biggest obstacle to use

However, the existing treatment methods (washing or Na 2 CO 3 solution cleaning (MSWI bottom ash) can not effectively alleviate the foaming and expansion phenomenon, but only partially relieves the effect of swelling and deformation, and has no obvious effect on improving the strength of MSWI bottom ash alkali-excited specimens

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