钨尾矿预处理制备矿物聚合材料

Pretreatment of Tungsten Tailing for Geopolymer Synthesis

按照"摇床重选→机械球磨→碱熔融"的步骤对钨尾矿进行逐级预处理,将各级预处理所得的钨尾矿分别与铝校正料偏高岭土复合后在碱激发剂作用下制备矿物聚合材料。通过正交实验对原料配方进行优化,研究各因素对抗压强度指标的影响规律,探索制备矿物聚合材料的优化原料配方及主要影响因素,并借助XRD和ESEM-EDS对优选矿物聚合材料试样的微观结构进行表征。结果表明:随着对钨尾矿的逐级预处理,其反应活性逐级增加,经三级预处理之后所得钨尾矿制备的矿物聚合材料试样7 d龄期最高抗压强度可达到48.45 MPa;对于以各级预处理所得钨尾矿制备的矿物聚合材料,正交设计中的因素对它们抗压强度指标的影响规律多数不一样,对抗压强度影响程度最大的因素也各不相同;ESEM分析表明优选试样内部形成了对其强度起支撑作用的致密结构,EDS分析表明所选区域凝胶相的Si/Al比例与实验设计的Si/Al比例不一致。

Based on the procedure of ＂ gravity separation by shaking table → mechanical ball milling →alkali fusion ＂,tungsten tailing was pretreated step by step. In combination with the Al-correcting material（ i. e. metakaolin）,the pretreated tailing obtained from every step was respectively converted into geopolymer with alkaline activator. The material ＇ s formulas were optimized by orthogonal experiments. Influence rules of each factor on compressive strength index was investigated. The optimal material ＇s formula and the principal influence factor was explored. Moreover,microstructure of the optimized geopolymer sample was characterized by XRD and ESEM-EDS analyses. Results showed that,reactivity of tungsten tailing increased with further pretreatment. Geopolymer samples prepared with the tungsten tailing by three-step pretreated tungsten tailing could reach the highest 7 d compressive strength of 48. 45 MPa. For geopolymer prepared with different pretreated tungsten tailing,influence rules ofvarious factors on the compressive strength of samples were mostly different. Besides,the most important factors influencing compressive strength were also different. ESEM analysis indicated that the dense structure formed in the optimized sample played a supporting role in strength performance. EDS analysis revealed that Si / Al ratio ofgel phase from theselected area failed to match the Si / Al ratio from experimental design.