Properties and mechanism of mine tailings solidified and filled with fluorgypsum-based binder material

Abstract

The properties and microscopic structure of tailings solidification bodies, the hardening mechanism of the fluorgypsum-based binder material (FBBM) and tailings solidification mechanism were investigated. FBBM consisted of 40% fluorgypsum, 25%–50% blast furnace slag, 10%–35% ordinary Portland cement clinker(OPCC) and 1% activator, which was good material in binding iron ore tailings.XRD analysis showed that the properties of tailings solidification bodies was related to its ettringite content.SEM and XRD analyses of tailings solidification bodies showed that the chemical reaction was produced between FBBM and tailings in the whole hydration process. The hydration of the resulting gel material covered the surface of the tailings particles and formed a gel structure. A large number of ettringite crystals and the remaining board-like gypsum crystals took each end and constituted the structural skeleton. The filamentous network-like calciumsilicate-hydrate(C-S-H) gel bonded firmly together with ettringite crystals, dehydrated gypsum crystals and granular tailings, and formed an extremely dense whole.

Keywords

fluorgypsum / tailings solidification body / blast furnace slag / toxicity / ettringite

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