改性钨尾矿地聚合物的制备及其性能研究

发布时间：2018-06-18 18:24

  本文选题：钨尾矿 + 地聚合物　； 参考：《江西理工大学》2017年硕士论文

【摘要】：随着钨行业的快速发展,钨尾矿的产生将逐渐加剧。大量的钨尾矿占用土地面积、危害人体健康、对环境造成极大安全隐患,也严重制约了钨行业的发展。因此,对钨尾矿的资源化利用势在必行。另一方面,地聚合物是近年来热门的研究材料,诸多优良性能使其具有广泛的应用前景。本文在对钨尾矿特性研究基础上,对其预处理改性,进行了利用改性钨尾矿制备地聚合物的研究,具体内容和结果如下:(1)通过碱-热-球磨的预处理方式制备改性钨尾矿,对改性钨尾矿的特性进行了分析,主要包括化学成分、物相组成、粒径分布。结果表明,改性钨尾矿活性提高,适合作为地聚合物的原料。进行了蒸压养护制度下改性钨尾矿制备地聚合物研究,确定养护制度为:蒸压养护压力为1.0MPa,养护时间为2h,卸压时间为30min,该条件下制备的地聚合物试样7天抗压强度达26.62MPa。XRD、FTIR、SEM分析发现,蒸压下,地聚合物试样主要以无定型物质存在,Al进入到Si-O-Si结构中,聚合反应程度较彻底,结构密实。(2)分别在钨尾矿中加入NaOH、Na2CO3、KOH、K2CO3在500℃、650℃、800℃下煅烧,加入15%的粉末硅酸钠制备地聚合物反应前驱物。按照液固比0.12加水制备地聚合物试样并在常温和70℃高温湿气下养护。结果表明,以KOH为助剂,在800℃下煅烧所得固体反应前驱物具有较好的活性,所制备的地聚合物试样7天抗压强度达15.41MPa以上。XRD、FTIR、SEM分析发现,该试样以无定型物质存在为主,含有少量石英,Si-O-Si结构逐渐向Si-O-Al结构转变。试样结构均一,密实化程度较好。此外还发现,高温湿气养护阻碍了地聚合反应的进行,不利于试样抗压强度的发展。(3)进行了钨尾矿地聚合物抗冻性研究,考察了硅灰掺量、液固比及成型压力对试样抗冻性能的影响。结果表明:当硅灰掺量为15%、液固比为0.25、成型压力为20MPa时,地聚合物试样具有较好的抗冻性能,在质量损失率为5%时冻融循环次数达70次,抗压强度损失率仅为12.77%。其冻融循环次数较多,抗压强度损失率较小,因此,抗冻性较好。SEM分析发现,冻融循环对试样结构产生一定破坏,凝胶组分减少。(4)进行了钨尾矿地聚合物热稳定性研究,考察了骨料掺量与级配对试样热稳定性的影响。结果表明:当骨料掺量为50%,其中20-60目和60-100目各占50%时,地聚合物试样在1000℃下的抗压强度是未做煅烧的2.44倍,其热稳定性较好。XRD、FTIR、SEM分析发现,高温下,地聚合物试样的物相组成未明显改变,少量Si-O-Al结构向Si-O-Si结构结构转变,凝胶组分微量减少,试样总体结构未明显改变。综上所述,钨尾矿地聚合物具有优良的抗冻性和热稳定性,利用钨尾矿制备地聚合物具有一定的可行性,然而试样抗压强度普遍偏低,因此,在提高钨尾矿综合性能上还有待进一步研究。
[Abstract]:With the rapid development of tungsten industry, the production of tungsten tailings will be intensified gradually. A large number of tungsten tailings occupy land area, endanger human health, cause great hidden danger to environment, and seriously restrict the development of tungsten industry. Therefore, the utilization of tungsten tailings is imperative. On the other hand, geopolymer is a hot research material in recent years. In this paper, based on the study of the characteristics of tungsten tailings, the preparation of geopolymer by modified tungsten tailings was studied. The specific contents and results are as follows: (1) the modified tungsten tailings are prepared by the pretreatment of alkali-thermal-ball milling. The characteristics of modified tungsten tailings are analyzed, including chemical composition, phase composition and particle size distribution. The results showed that the activity of modified tungsten tailings was improved and it was suitable to be used as the raw material of geopolymers. The preparation of geopolymer from modified tungsten tailings under autoclaved curing system was studied. The curing system is determined as follows: the curing pressure is 1.0 MPA, the curing time is 2 h, and the pressure relief time is 30 min. The compressive strength of the geopolymer samples prepared under this condition is 26.62 MPa.XRDX FTIRN SEM analysis, and it is found that under the autoclaved pressure, the compressive strength of the geopolymer samples prepared under this condition is 26.62MPa.XRDX FTIR SEM. The samples of geopolymers are mainly deposited as amorphous materials into Si-O-Si structure. The degree of polymerization is relatively thorough, and the structure is dense. The samples are calcined at 500 鈩，

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