WANG J X, YANG H, YANG X L,et al.Optimization and mechanistic analysis of flocculation and sedimentation parameters for unclassified gold mine tailings[J].Journal of Henan Polytechnic University(Natural Science) ,2025,44(5):91-99.

DOI:10.16186/j.cnki.1673-9787.2023070017

Received: 2023/07/10

Revised: 2023/12/08

Published:2025/07/23

Optimization and mechanistic analysis of flocculation and sedimentation parameters for unclassified gold mine tailings

Wang Jinxing1,2, Yang Han1,2, Yang Xiaolin1, Chen Fengbin1,2, Jiao Huazhe1,2

1.School of Civil Engineering， Henan Polytechnic University， Jiaozuo  454000， Henan， China；2.State Collaborative Innovation Center of Coal Work Safety and Clean-Efficiency Utilization， Jiaozuo  454000， Henan， China

Abstract: Objectives To address the challenges of poor thickening performance and low underflow concentration of unclassified tailings， this study aims to optimize flocculation and sedimentation parameters and analyze the underlying mechanisms.  Methods A suitable flocculant was selected and a test system simulating a deep cone thickener was constructed. Four factors—rake rotation speed， feed mass concentration， flocculant dosage， and flocculant solution concentration—were used as independent variables， with underflow mass concentration as the response variable. Using Design-Expert software， 29 experimental runs were designed. A quadratic polynomial regression model was developed based on the results. Variance analysis and response surface methodology （RSM） were applied to evaluate the effects of individual and interactive factors and to identify the optimal flocculation parameters. Mechanistic analyses of the flocculant action and rake shear effects were also conducted.  Results In the thickening tests using anionic polyacrylamide with a molecular weight of 20 million as the flocculant， the feed mass concentration was identified as the most significant single factor affecting the underflow concentration. The interaction between rake rotation speed and feed concentration was the most influential factor overall. Conclusions The optimal combination of flocculation parameters was determined as follows： feed mass concentration of 21.24%， rake rotation speed of 0.121 r/min， flocculant dosage of 6.73 g/t， and flocculant solution concentration of 0.031%. Under these conditions， the underflow concentration reached 55.28%. At a moderate dosage， the hydrolyzed polymer chains were uniformly dispersed in the solution and effectively adsorbed onto the tailings particles. Both overdosing and underdosing inhibited the bridging function of the flocculant. Rake-induced shear breaks the enclosed floc structures， releasing water trapped inside， allowing flocs to bind with more tailings particles， thereby increasing their density and promoting settling， which ultimately enhances the thickener’s underflow concentration.

Key words:unclassified tailings;underflow concentration;factor interaction;flocculation-sedimentation model