Research on Preparation and Performance of Vandium Tailings-based Geopolymer
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Research on Preparation and Performance of Vandium Tailings-based Geopolymer Tie-jun Chen, Yi-min Zhang, Xiang-ke Jiao, Jie Zhao School of Resource and Environmental Engineering, Wuhan University of Science and Technology, Wuhan 430081, China, Email: [email protected] ABSTRACT Vanadium-beard bone coal is one of important vanadium resources in China. to extract vanadium tailings from Stone coal is prduced after extracted vanadium from stone coal through the roasting, leaching and other processes. About 120-150 tons of tailings will be produced in extracting 1 ton of vanadium pentoxide. A lot of tailings that are willfully piled up have caused serious environmental pollution and wasting of resources; it is therefore necessary to realize its resource utilization. This study increases the activity of vanadium tailings by means of alkali fusion, and then uses different alkali activators to react with vanadium tailings so that geopolymer with high value added is produced. Sample of geopolymer is acquired from mixture containing vanadium tailings, alkali activators, water and a little sodium aluminate through compression-molding process under 20MPa pressure. After cured in room temperature for three days, the maximum compressive strength of the sample can reach 36.2MPa. XRD analysis indicates: quartz, the major crystal phase in vanadium tailings is decomposed and the activity of vanadium tailings is heightened. FTIR and SEM analyses show: structural change having important impact on the mechanical strength of geopolymer occurred during the process of vanadium tailings generating geopolymer. Key words: vanadium tailings, alkali fusion, alkali activator, geopolymer
INTRODUCTION Geopolymer is a kind of new material polymerized from Al-O-Si network structure, in which the oxygen-silicon tetrahedron and aluminum-oxygen tetrahedron is alternately bonding through sharing all oxygen atoms [1]. Such special structure makes it similar to organic high polymer, ceramics and cement, yet different from the abovementioned materials, featuring high strength, fast hardening property, high temperature resistance, insulation, resistance to acid and corrosion, ability to adsorb harmful toxicant, etc. [2-5]; therefore, it is an inorganic polymeric material of high performance with great potential in development. The major raw materials for preparing geopolymers at present include active aluminosilicate minerals or industrial solid waste [6-8].In the studies at home and abroad, mainly metakaolin or fly ash is used as raw material. Under the function of alkali activator, inorganic cementitious material of certain strength is formed [9-12]. However, there are
relatively few studies using mine tailings as raw material for preparing geopolymer, which is probably because of the low content of amorphous active constituent and changeable chemical compositions. To extract vanadium tailings from Stone coal (hereinafter referred to as “vanadium tailings") is to extract post-vanadium slags in the stone coal through procedures such as baking and leaching.
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