The Research On Producing Less-Clinker Cementitious Materials And Steam-Cured Brick With Semi-Dry Desulfurization Ash

Semi-dry desulfurization ash technology is well considered as the most economical and effective method for small power plant and industrial boiler, for its special characterization, such as small place occupation, easy-controlled, no waste water generation. However, people do not have the enough realization on the basic specification of the desulfurization ash, and this is the big barrier for the promotion for the semi-dry technology. In this article, three kinds of representative desulfurization ash are studied.The characters of the desulfurization ash are researched in the use of SEM, XRD, size-distribution and DTA-TG, and the activation of them are analyzed. At last, the methods of construction materials resource of the desulfurization ash namely producing less-clinker cementitious materials and steam-cured brick are studied comprehensively. The study about physical and chemical properties of desulfurization ash shows that: the principal mineral structure of the three kinds of semi-dry desulfurization ash are mainly calcium carbonate, calcium hydroxide, calcium sulfite, calcium sulfate, silica, mullite, etc; specific surface area is 28.15~1 054.31 m2·kg-1; particle size is 0.1~300μm; the three desulfurization ash can be called calcium-based desulfurization ash as the contain of CaO is high; the content of SiO2 and Al2O3 in desulfurization ash is a positive correlation to of cementing material, but content of CaO is a negative correlation; the activity of 1# desulfurization ash is greater than 2#,3 # desulfurization ash.The research on less-clinker cementitious materials preparated by desulfurization ash, clinker, steel slag and slag has shown that: raw materials are stimulated the activity compoundly by mechanical activation and chemical activation. The orthogonal experiment and follow-up optimization experiments determine the optimal proportion: 1# desulfurization ash 12%, clinker27%, proportion of steel slag and slag is 1:4, Na2SO41.5%, desulfurization gypsum 3%, water reducing agent 0.5%. The technical performance of cementitious materials by optimal proportion can meet the standard requirements of GB13590-2006《portland steel and iron slag cement》, the strengthof 3 d, 28 d can reach strength grade 42.5.This cementitious materials has good strength development law and shrinkage, anti-sulfate erosion, frost resistance are good.The research on steam-cured brick preparated by desulfurization ash, fly ash, and aggregate has shown that: frost resistance and shrinkage of the steam-cured bricks perform well and the technical performance can meet the requirements of MU15 in JC239-2001 《fly ash brick》in the situation of 2# desulfurization ash 20%~25%, fly ash44%~49%, aggregate 25%(proportion of grit and carpolite is 2:3), compound activator NH 1%,water 25% , digestion time 36 h, curing 7 h at 90℃or 3# desulfurization ash 40%~45%, fly ash29%~34%, aggregate 25%(proportion of grit and carpolite is 2:3), compound activator NH 1%,water 25% , digestion time 24 h, curing 8 h at 95℃.