Preparation Of Eco-Cementing Matereals In Utilization Of Modified Sintering Flue Gas Desulfurazation Ash With Steel Slag

With the intensive development of the iron and steel industry,sintering flue gas desulfurization technology attracts much more attention and focus.The method of semi-dry technology is widely used due to its advantages of saving places,easy operation and short process.The by-products of circulating fluidized bed(CFB) semi-dry flue gas desulfurization is ash.Because of a large amount of CaSO₃,the by-products can not be used into the cement production directly.However,after the long-time stacking,not only many cherish soild resources are occupied,but also generates the environmental pollution.The eco-cementing materials have the advantages of saving mineral resources. saving land and reducing emisson.Sintering flue gas desulfurization ash,Steel slag and ground blast furnace slag(GBFS) contain lots of CaO,Al₂O₃ and other componets which have the potential activity.If the utilization of the modified sintering flue gas desulfurizationash(MSFGDA) could come to the true,the environmental pressure which is generated by the discharge of large amouts of industrial solid waste,as well as subsititue some clinker.Therefore,the complete utilization of modified sintering flue gas desulfurization ash and other industrial solid waste has the significant meaning.The article analyzed the sintering flue gas desulfurization ash with the methods of chemical analysis,nuclear magnetic resonance(NMR),DTA-TG.The feasibility of preparing the ecological cementing materials in the utilization of sintering flue gas desulfurization ash with GBFS.steel slag.and other additives is studied by Orthogonal experiments and single-factor experiments.The steel slag.GBFS and clinker are pre-ground respectively.Then all the raw materials are co-ground together.The MSFGDA cementing materials have good soundness,hydration properties and mechanical properties,the initial and final set are qualified.The mechanical property of the cementing materials could meet the(GB13592-92＜steel slag and GBFS cement standard＞in the composition of MSFGDA 20%,CFII1.5%,water reducing agent 0.5% and clinker 20%;The amounts of GBFS is between 12%-44%,steel slag is between 11%-44%.In the condition of the amounts of GBFS,steel slag,clinker and other admixture are fixed,the compressive and bending strength of the cementing materials drop obviously when the amounts of MSFGDA is over 30%.The effectiveness of cementing materials hydration products in differert crystal structures is analysed by SEM and XRD.The researching results show that the AFt and other irregular C-S-H gelatin are the most avaliable in the hydration products(28 d) which proporation of GBFS and steel slag is 3:2,the amounts of ash is 20%.These hydration products interlace each other formulating the tightest structure to make sure the strength could be the best one.The experiments of durability show that this kind of cementing materials have the good ability of sulfate resistence,sulphate-resistence,frost resistence,but the drying shrinkage is not as good as expected,the improvmenm should be done in the future.