【作者】 王志强；

【导师】 吕宪俊； 连民杰；

【作者基本信息】 山东科技大学 ， 矿物加工工程， 2017， 硕士

【摘要】 硅质尾矿作为我国选矿尾矿的主要类型之一,其化学成分以SiO2、Al2O3为主,这与火山灰质材料近似,具备与Ca(OH)2反应生成水硬性物质的潜在性能。本文以激发硅质尾矿的火山灰活性为目的,研究机械粉磨、化学激发剂对硅质尾矿火山灰活性的活化作用,以及活化尾矿在尾矿复合水泥中的应用。机械粉磨研究表明,尾矿的火山灰活性随其比表面积的不断增加而显著增强。未粉磨时,尾矿的比表面积为233.20m2/kg, 28d活性指数仅为53.89%,当粉磨至5min,尾矿的比表面积达到495.10m2/kg,28d活性指数达到65.65%,粉磨至45min,在比表面积为849.40m2/kg, 28d活性指数达到峰值为80.94%。在尾矿与粉煤灰混合研磨试验中,比例为1: 1时,比表面积达到1169.80m2/kg,28d抗压强度就可以达到50.25MPa,28d活性指数为94.56%,此数据明显高于尾矿单独的粉磨活性(尾矿单独粉磨时,比表面积为1161.70m2/kg时,28d抗压强度为37.61MPa,28d活性指数为73.78%)。CaO和CaCl2对硅质尾矿混合材料具有较好的早强作用,CaO的适宜掺量为2%,此时试样的比表面积为880.40m2/kg,3d抗压强度达到22.25MPa,28d活性指数为81.88%; CaCl2的适宜掺量为1%,此时比表面积为903.90m2/kg, 3d抗压强度达到22.14MPa,28d活性指数为81.74%。通过活化尾矿在尾矿复合水泥中应用性能的研究,发现掺加尾矿后水泥的凝结时间伴随着尾矿的比表面积增加而逐渐降低,体系中的水泥标准稠度用水量也逐渐增大。在尾矿比表面积达到840.30m2/kg,掺加量为30%时,可以满足P·Ⅱ425要求,28d的抗折、抗压强度为6.86MPa、43.91MPa,凝结时间为201min、253min,标准稠度用水量为28.20%,安定性合格;将尾矿与粉煤灰进行复配比例为1: 1用作复合水泥的混合材料,比表面积达到1175.50m2/kg时,满足P·Ⅱ425要求混合材料的掺加量可以达到50%,水泥28d的抗折、抗压强度为7.09MPa、43.77MPa,凝结时间为237min、311min,标准稠度用水量为29.80%,安定性合格。更多还原

【Abstract】 Silica tailings are one of major mine tailings in China. The basic chemical compositions contain mainly SiO2 and Al2O3, which are similar with pozzolanic materials. There is potential pozzolanic activity that could react with alkaline compounds such as Ca(OH)2. In this paper, the study purpose is to improve pozzolanic activity of tailings by mechanochemical activation. The studies consist of effect of mechanical grinding and chemical activator on pozzolanic activity of tailings, application of tailings activated used in composite cement.Researches showed that the pozzolanic activity of tailings could increase with increase of the specific surface area by mechanical grinding.Compared with raw tailings whose specific surface area was 223.20m2/kg,the 28d activity index was 53.89%, when specific surface area was 495.10m2/kg during grinding for 5min, the 28d activity index was 65.65%.When the specific surface area was 849.40m2/kg, the 28d activity index reached 80.94%. When ratio of tailings and fly ash was 1:1, the specific surface area was 1169.80m/kg,the compressive strength of sample reached 50.25MPa in 28d, the 28d activity index was as high as 94.56%.That performances were higher than that of tailings whose specific surface area was 1161.70m2/kg, and the compressive strength of samples reached 37.61MPa in 28d, the 28d activity index was 73.78%. There are obvious differences in reinforced pozzolanic activity of tailings by chemical activator. CaO and CaCl2 could effectively improve the compressive strength of the cement in the early hydration process. While the appropriate amount of CaO was 2% and the specific surface area was 880.40m2/kg, the 3d compressive strength of the cement was 22.25MPa, and 28d activity index was 81.88%. The 3d compressive strength of the cement was 22.14MPa,and 28d activity index was 81.74%,while CaCl2 was about 1%and the specific surface area was 903.90m2/kg.By study for tailings used in composite cement, it found that the setting time decreased gradually with the increase of the specific surface area of tailings, but the water consumption of cement standard consistency increased. When the specific surface area was 840.30m2/kg, flexural strength and compressive strength of cement with 30% of tailings were 6.86MPa and 43.91MPa in 28d, and the setting time was 201min and 253min, the water consumption of cement standard consistency was 28.20%, stability qualified, which could meet the requirements of P·Ⅱ 425.Tailings and fly ash were mixed by 1:1 in composite cement, specific surface area was up to 1175.50m2/kg, it could meet requirements of P·Ⅱ425 in amount of 50%. Its properties were that the flexural and compressive strength of cement in 28d were 7.09MP and 43.77MPa, and the setting time was 237min and 311min, the water consumption of cement standard consistency was 29.80%, stability qualified.更多还原