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Research On Preparation Of Light Wall Materials Using Soda Residue

Posted on:2015-12-18Degree:MasterType:Thesis
Country:ChinaCandidate:Z H KangFull Text:PDF
GTID:2272330452458187Subject:Materials Physics and Chemistry
Abstract/Summary:PDF Full Text Request
Soda residue is a kind of industrial waste discharged by ammonia-soda process duringproducing soda. Because soda residue contains high content of calcium salt, it can be usedas calcareous raw materials to prepare light weight wall materials, which provides a newway to utilize the soda residue.The specimens were prepared by soda residue as main raw material mixing with flyash, a small amount of cement and lime through autoclaved curing. For the specimenswhich are not aerated, the compressive strength can be up to24MPa. The experimentalresults show that the appropriate parameters are that the soda residue content should be lessthan60%of the total quality of raw materials, the molecular ratio of CaO to SiO2(C/S) is1.2, the autoclaved curing temperature is160℃to180℃and the curing time is3h to5h.Using aluminum powder as gas agent and fixing soda residue content as60%, theeffects of the proportion of raw materials and the autoclaved curing system on theproperties of specimens were studied. The variables include C/S, the ratio of water tomaterial, amount of aluminum powder, amount of water glass, fineness of soda residue,autoclaved curing temperature and curing time. The suitable proportion of raw materialsand the parameters were obtained from the results, namely the C/S is0.8~1.2, the ratio ofwater to material is0.66, the amount of aluminum powder is0.1%, the autoclaved curingtemperature is180℃~200℃and the curing time is5~7hours.The scumming experiment and the alkali leaching test were conducted. The resultsshow that there is no scumming for the aerated specimens. The alkali leaching experimentresults show that when C/S is1.2and1.4, the alkali leaching content is relatively high, andincreasing curing temperature and prolonging curing time reduce the alkali leachingcontent, however, adding water glass increases the alkali leaching content.The mineral types of aerated specimens and their microstructure were studied usingthe modern testing techniques such as XRD and SEM. The different crystals of hydratedcalcium silicate, such as CSH(A), CSH(B) and tobermorite C5S6H5, make contribution tothe strength. Tobermorite makes larger contribution to the strength under suitableautoclaved curing system and its morphology is fibrous or willow sharp. The existence ofquartz (SiO2) and hydrogarnet (C3ASH4) go against with the increment of the strength.Feldspar-like minerals, such as nepheline and scapolite solidify a certain amount of alkaliin the soda residue, and resulte in reducing the amount of alkali leaching and scumming.
Keywords/Search Tags:soda residue, lightweight block, autoclaved curing, mechanical property, alkali leaching
PDF Full Text Request
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