研究了激发剂对氟石膏的激发效果和机理,复合氟石膏胶结材的强度、软化系数和浸出毒性.通过NaOH、Na2 SO4和NaF对氟石膏激发试验,确定最优掺量均为1％.在此基础上,采用矿渣、粉煤灰、熟料对用量80％以上氟石膏进一步改性,发现Na2 SO41％、矿渣2.5％、粉煤灰5％和氟石膏89％复合胶结材性能最好,28 d抗压强度可达12.25 MPa,软化系数可达0.70,浸出氟离子浓度降低到0.748 5 mg/L.SEM和XRD分析发现水化形成的二水石膏晶体与少量水化硅酸钙、钙矾石及氟化钙互相填充包裹,阻碍了水分进入,改善了复合胶结材耐水性能和降低了浸出毒性.%Effect and mechanism of activation of activator to fluorgypsum, strength, softening coefficient and leaching toxicity of composite cementitious material are studied. Through activation testing of NaOH, Na2SO4 and NaF, the optimum adding quantity was defined as 1%. On the basis of it, 80% fluorgypsum was further processed to improve its quality with slag, fly ash and clinker. With 1% Na2SO4,2.5% slag, 5% fly ash and 89% fluorgypsum, the cementitious material properties were excellent; the 28-day compressive strength could reach 12. 25 Mpa; the softening coefficient was 0. 70; and the concentration of fluoride could be reduced to 0. 7485 mg/L. The analysis of SEM and XRD show that gypsum, a few calcium silicate hydrate, ettringite and calcium fluoride are filled and packed each other, which hampers water enter particle structures, increases the water resistance of cementitious material and reduces leaching toxicity of cementitious material.
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