Method for preparing modified desulphurized ash

Abstract

The invention discloses a method for preparing a modified desulphurized ash. The method comprises the steps of first adding water to the desulphurized ash to be sufficiently mixed so that the water content of the desulphurized ash reaches 20-40 wt%; and placing the desulphurized ash for 20-40 days at a room temperature and at a humidity of 70-100% so as to obtain the modified desulphurized ash, wherein the content of free carbon oxide in the modified desulphurized ash is less than 5%. In the invention, the desulphurized ash is first pre-treated and modified and then the modified desulphurized ash is applied to cement production to eliminate the problem of bad cement soundness brought by doping the dry desulphurized ash into the cement, and thus the preparation method effectively solves the resource utilization difficulty of the desulphurized ash at present, reduces clinker consumption and production cost, saves energy and reduces emission.

Description

technical field [0001] The invention belongs to the field of waste gas and waste slag treatment, and more specifically, the invention relates to a preparation method of modified desulfurization ash. Background technique [0002] The rapid development of the flue gas desulfurization industry has effectively curbed SO 2 Pollution situation, but also produced a large number of desulfurization by-products. According to different desulfurization processes, desulfurization by-products can be roughly divided into two categories: wet desulfurization gypsum and semi-dry desulfurization ash. It is also estimated that by 2010, my country will discharge more than 1,500 and 1.4 million tons of desulfurization gypsum and desulfurization ash each year respectively. At present, there are few studies on the comprehensive utilization of flue gas desulfurization by-products, and a large number of by-products are still stacked in the open air, which not only occupies land resources, but also ...

AI Technical Summary

Problems solved by technology

At present, there are few studies on the comprehensive utilization of flue gas desulfurization by-products, and a large number of by-products are still stacked in the open air, which not only occupies land resources, but also causes secondary pollution to the environment

In addition, the by-products of desulfurization are not effectively utilized, which will cause waste of resources

[0003] The characteristics of desulfurization ash have a great adverse effect on its comprehensive utilization

The content of free calcium oxide in desulfurization ash is relatively high (generally above 10%), and Ca(OH) is continuously generated during the long-term hydration process 2 If it is directly mixed in a large amount in cement production, too high free calcium oxide will cause the volume of cement products to expand continuously during the hydration process, which will directly or indirectly affect the safety performance of cement products and even the safety performance of the building itself; There are many reports that the subgrade built with dry-drained desulfurized ash will expand and crack after a few weeks, resulting in poor stability of the concrete. At present, the application of dry-drained desulfurized ash is mainly to find the elimination of volume Pretreatment methods for poor stability

In view of the above reasons, the resource utilization of desulfurization ash is limited and has not yet been industrialized. At present, a large amount of desulfurization ash is still not effectively utilized, which causes waste of resources and secondary pollution to the environment

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