Open Access

ARTICLE

The Micro-Scale Mechanism of Metal Mine Tailings Thickening Concentration Improved by Shearing in Gravity Thickener

by Huazhe Jiao^1,2, Yachuang Wu¹, Wei Wang^2,*, Xinming Chen¹, Yunfei Wang¹, Juanhong Liu³, Wentao Feng⁴

1 International Joint Research Laboratory of Henan Province for Underground Space Development and Disaster Prevention, Henan Polytechnic University, Jiaozuo, 454000, China
2 College of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo, 454000, China
3 Civil and Resource Engineering School, University of Science and Technology Beijing, Beijing, 100000, China
4 No.11 Coal Mine of Pingdingshan Tianan Coal Mining Co., Ltd., Pingdingshan, 467000, China

* Corresponding Author: Wei Wang. Email:

(This article belongs to the Special Issue: New Trends in Sustainable Materials for Energy Conversion, CO₂ Capture and Pollution Control)

Journal of Renewable Materials 2021, 9(4), 637-650. https://doi.org/10.32604/jrm.2021.014310

Received 17 September 2020; Accepted 21 October 2020; Issue published 01 February 2021

Abstract

Higher concentration is beneficial for the Paste and Thickened Tailings (PTT) operation in metal mine. Partial paste thickeners are produced lower density underflow. Flocculated tailings are intended to form a water entrapped network structure in thickener, which is detrimental to underflow concentration. In this study, the continuous thickening experiment was carried out for ultra-fine tungsten tailings to study the influence of rake shearing on underflow. The micro pores structure and seepage flow in tailings bed before and after shearing are studied by CT and simulation approach to reveal the shearing enhancement mechanism of thickening process. The results shown that, the underflow concentration is increased from 61.4 wt% to 69.6 wt% by rake shearing in a pilot scale thickener, the porosity decreased from 46.48% to 37.46%. The entrapped water discharged from sticks structure more than sphere spaces. In items of seepage, after shearing, the seepage flow channel of tailings underflow is becoming longer, which caused the decreasing average flow rate decreases and absolute permeability. The absolute permeability is negatively correlated with tortuosity. The rake shearing can destroy the flocs structure; change the effective stress to increase the concentration. Higher underflow concentration improves the waste recycling and water recovery rate, especially for arid areas.

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