烟气脱硫灰中CaSO_3对水泥胶砂性能的影响

Effect of CaSO_3 in flue gas desulphurization ash on performance of cement mortar

为了明确低温脱硫副产物中CaSO3与水泥胶砂性能间的关系,采用在粉煤灰中掺入不同比例的CaSO3·1/2H2O,然后置于100℃烘焙以模拟尾部烟气脱硫灰,进行工作性、强度、耐硫酸盐侵蚀性、护筋性试验。结果表明：烟气脱硫灰中CaSO3·1/2H2O含量在4%-12%范围内均可改善流动性,但含量大于4%后其流动性改善幅度开始下降;烟气脱硫灰的强度随CaSO3·1/2H2O含量增加而日益降低,对28d强度的影响程度显著高于7d的;烟气脱硫灰中CaSO3·1/2H2O均降低抗腐蚀系数,且含量大于8%后下降更为明显;CaSO3·1/2H2O含量对水泥胶砂中钢筋无影响。

To study the relations between the performances of cement mortal based material and CaSO3 in by-products obtained from the low temperature desulfurization,flue gas desulphurization（FGD） ash was simulated based on the desulphurization reaction temperature and the content of calcium sulfate,which is the ordinary fly ash mixed with different weight percentages of CaSO3·1/2H2O followed by drying at 100 ℃.And then by the experiments of workability, strength, sulfate resistance and rebar corrosion, the effect of the fly ash with different contents of CaSO3·1/2H2O on material properties were studied. The results show that： compared with ordinary fly ash, the desulphurization ash contained 4%—12%CaSO3·1/2H2O can improve workability, but with a 4% threshold over the critical value,and that the improving ability declines. Secondly,increasing the content of CaSO3·1/2H2O in desulphurization ash can decrease the ash strength, and the effect of 7 d strength is bigger than that of 28 d.Thirdly, the increase of calcium sulfate in the desulphurization ash can decrease the resistance to sulfate attack,especially for more than 8% of CaSO3·1/2H2O, but it is harmless to steel rebar.