Modified desulfurization ash for cement and concrete and preparation method thereof

Abstract

The invention discloses modified desulfurization ash for cement and concrete and a preparation method of the modified desulfurization ash. The modified desulfurization ash for cement and concrete is prepared from desulfurization ash and an oxidizing agent through mixing at normal temperature, wherein the oxidizing agent comprises the following components by weight percentage: 70-80% of manganese dioxide, 5-10% of acetic acid and 10-25% of desulfuration residue, the conversion rate of CaSO4.2H2O in the modified desulfurization ash is 95-98%, the mixing amount of the modified desulfurization ash in cement and concrete is 5-25% (by weight percentage). The modified desulfurization ash has early compressive strength improved remarkably when being added into the cement and the concrete, has the compressive strength hardly reduced after being solidified completely, and has little swelling stress.

Description

technical field [0001] The invention belongs to the technical field of concrete materials, and in particular relates to a low-expansion modified desulfurization ash used in cement and concrete and a preparation method thereof. Background technique [0002] Dry desulfurization mainly adopts NID desulfurization process. The NID technology uses quicklime or slaked lime as an absorbent, mixes it with the recycled fly ash with a certain alkalinity captured by the dust collector, and injects it into the reactor after humidification, so that it is evenly distributed in the hot flue gas. At this time, the water on the surface of the absorbent is evaporated, the flue gas is cooled, but the humidity increases, and the SO in the flue gas 2 , HCl and other acidic components are absorbed to generate CaSO 3 .0.5H 2 O and CaCl 2 .4H 2 O. The final desulfurization products and unreacted absorbent captured by the dust collector are partly injected into the mixed humidification device, ...

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Problems solved by technology

[0003] Dry desulfurization ash is currently in concrete, because its sulfite content is as high as 18.88%, resulting in unstable volume expansion of concrete in the later stage, and the performance of dry desulfurization ash changes greatly, and there are many impurities and types, especially sulfite The content is too high to be used. Currently, it can only be dumped and disposed of, resulting in waste of resources and secondary pollution. It cannot be used in concrete so far.

[0004] CN201010546668.8 pointed out a rapid oxidant, but did not specify the conversion rate. Experiments have proved that there is a defect that sulfite is not high enough to be applied to the cement industry, and there is no corresponding technical application in the cement industry. explore

[0005] Adding A study was conducted on different proportions of desulfurized ash to produce cement mixtures. The research results showed that semi-dry and semi-wet flue gas desulfurization ash can be used to produce raw materials such as bricks and cement mixtures, but did not specify the specific formula, product performance and usage methods.

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