富硅钒尾矿热活化及改性制备绿色环保“一体化”地聚合物

本研究的目的是通过热活化和改性的方式，将富硅钒尾矿制备成地聚合物前驱体。在热活化阶段，钒尾矿和氢氧化钠均匀混合后在高温下煅烧。掺入偏高岭土来调节热活化后钒尾矿的硅铝比例，并得到地聚合物前驱体。结合TG-DSC，SEM，XRD以及活化钒尾矿浸出试验结果发现，在热活化过程中，钒尾矿首先被氢氧化钠腐蚀，然后在颗粒表面形成硅酸钠。热活化后的钒尾矿在加水后，钒尾矿颗粒表面的硅酸钠层溶解，释放出硅组分并形成碱性的溶液环境。偏高岭土能够在碱性环境中溶解释放出铝组分，并与先前释放的硅组分发生地质聚合反应。残余未反应的颗粒通过地质聚合过程中产生的凝胶连接，从而紧密的粘结在一起，随后养护硬化成具有优异机械性能的地聚合物产品。本研究能够提高了地聚合物技术在大规模工业现场应用的可行性，能够促进钒尾矿及其他富硅的固体废物的综合利用。

Fabrication of green one-part geopolymer from silica-rich vanadium tailing via thermal activation and modification

The aim of this investigation was to prepare geopolymeric precursor from vanadium tailing (VT) by thermal activation and modification. For activation, a homogeneous blend of VT and sodium hydroxide was calcinated at an elevated temperature and then modified with metakaolin to produce a geopolymeric precursor. During the thermal activation, the VT was corroded by sodium hydroxide and then sodium silicate formed on the particle surfaces. After water was added, the sodium silicate coating dissolved to release silicon species, which created an alkaline solution environment. The metakaolin then dissolved in the alkaline environment to generate aluminum species, which was followed by geopolymerization. The VT particles were connected by a gel produced during geopolymerization, which yielded a geopolymer with excellent mechanical performance. This investigation not only improves the feasibility of using geopolymer technology for large-scale and in-situ applications, but also promotes the utilization of VT and other silica-rich solid wastes.