A kind of calcium carbide slag absorbent and preparation method thereof

Abstract

The invention provides a calcium carbide slag absorbent and a preparation method thereof. The preparation method comprises the following steps: a) under an air atmosphere of 200° C. to 500° C., ultrafine carbide slag with a water content of 5 wt % to 40 wt % Grinding and drying until the moisture content is ≤3wt%, to obtain the calcium carbide slag absorbent; the linear velocity of the superfine grinding and drying medium is 50m / s-150m / s. Compared with the prior art, the preparation method provided by the present invention can maintain the active component of calcium hydroxide in the calcium carbide slag and fully stimulate the desulfurization of the carbide slag during the drying process of the calcium carbide slag through ultrafine pulverization and drying under specific conditions and parameters. activity, to obtain high-quality calcium carbide slag absorbent; the product has the characteristics of high effective calcium hydroxide content, large specific surface area, high pore volume, uniform and small particle size, and the product has significantly improved desulfurization performance indicators. Experimental results show that the high-quality calcium carbide slag absorbent provided by the present invention has an effective calcium hydroxide content ≥ 80wt%, and a specific surface area ≥ 18m 2 / g, pore volume ≥ 0.13cm 3 / g, D50≤20μm, D90≤70μm.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a calcium carbide slag absorbent and a preparation method thereof. Background technique [0002] "Comprehensive pollution control and waste recycling" is one of the key areas of the national medium and long-term scientific and technological development plan, and is closely related to comprehensive resource zoning and excessive resource consumption. As the country pays more and more attention to environmental protection, "ultra-clean emission" will inevitably become the mainstream trend of flue gas treatment of various industrial boilers, and the demand for high-quality absorbents is becoming more and more urgent. Compared with ordinary absorbents, high-quality absorbents have excellent properties such as high purity, high specific surface area, porosity, fine particle size and large pore volume, which can greatly improve desulfurization efficiency, and at the sam...

AI Technical Summary

Problems solved by technology

[0006] (1) Low purity: On the one hand, the direct heating of hot flue gas leads to serious carbonization of calcium hydroxide, which reduces the effective desulfurization components; on the other hand, the existing industrial flue gas directly heats carbide slag, and the flue gas temperature usually exceeds 450°C , resulting in the decomposition of calcium hydroxide, resulting in a further decrease in calcium hydroxide in the product

[0007] (2) The specific surface area is small: First, the quicklime blending method contains other components such as silica and calcium carbonate in the quicklime, which will cause some pores to be blocked by fine dust particles during the blending process; secondly, after the quicklime absorbs water and digests The product accounts for a large proportion of the absorbent, and this part of the slaked lime has underdeveloped pores (small porosity), resulting in a small specific surface area of ​​the prepared calcium carbide slag absorbent; finally, the direct hot flue gas drying method, the surface is prone to carbonization, and the newly formed Calcium carbonate is wrapped on the surface of calcium hydroxide, which shields the original pores of carbide slag and further weakens the desulfurization and denitrification activity

[0008] (3) Small pore volume: The size of the pore volume directly affects the absorption capacity of the acid gas. As explained above, the reason for the small specific surface area also leads to a decrease in the pore volume of the absorbent

[0009] (4) Large particle size: Wet calcium carbide slag has high viscosity, no matter chemical drying or direct flue gas drying, it is easy to agglomerate during the drying process, and the particle size is large