Improving dust resistance of mine tailings using green biopolymer

Abstract

The application of biopolymers as eco-friendly stabilizers to strengthen soils has received increasing attention in recent years. This paper presents an experimental and numerical investigation of using xanthan gum, a green biopolymer, to stabilize mine tailings (MT) for dust control purpose. Impact tests that simulate the saltation process during wind erosion were carried out to evaluate the effect of xanthan gum on the impacting resistance of MT, which is directly related to dust resistance. The impact test results show that the weight loss due to grain impacts is significantly reduced for biopolymer treated MT compared to the untreated, more biopolymer leading to greater reduction. The improved dust resistance of MT after biopolymer treatment may be attributed to the protective biopolymer coating formed at the surface of treated MT, which imparts the MT with a dense structure and enhanced cohesion, and therefore improves the impacting resistance. Numerical simulation using discrete element method (DEM) was performed to explore the underlying mechanisms of how biopolymer increases dust resistance of MT. The simulation results show that the bonding strength between MT particles increases linearly with biopolymer concentration; more biopolymer induces larger inter-particle bonding and therefore increases impacting and cracking resistance of MT.