Experimental Study On The Application Of Semidry And Semiwet FGD Residues In Cement Industry

With the intensifying control of SO2 in China, coal-fired plants start toadopt FGD(Flue Gas Desulfurization) technology, semidry FGD is one ofthe FGD technologies, which brings FGD residues that are different incomponents and properties from fly ash that exists without FGD. Aninvestigation should be carried on in the application of FGD residues toprevent secondary pollution and to utilize the new resource. Comparised with fly ash and high-calcium fly ash in components andproperties, it is shown that FGD residues can be applied in cement industryby taking the usage of fly ash. The experimental study of FGD residues in cement producing andbeing the mixture in cement is presented In this paper. Taking theproportion of calcium sulphate and calcium sulfite in FGD residuesproduced by semidry and semiwet FGD technology, FGD residues in theexperiments are made by pure calcium sulphate, pure calcium sulfite andfly ash. Experimental results show most cement made by FGD residues canreach the performance guideline of Portland cement 42.5R except the 3 daystrength of the first sample; being cement mixture, FGD residues have alittle effect on the water requirement under standard denseness; slight effecton setting; tiny effect on delaying setting time; no effect on the invariabilityof cement mixture in an appropriate mixing quantity range; the increasingcontent of CaSO4·2H2O leads the decrease of flexion strength andcompressive strength; but the increasing content of CaSO3·2H2O leads tothe other side; FGD residues cement show better performance than fly ashcement 32.5. Experimental results confirm that FGD residues can beapplied in cement industry . There are differences between the properties of mixed FGD residuesin this paper and the properties of FGD residues produced by engineering,the exact influence of real FGD residues in cement and mixture would begiven with farther experiments.