Optimization and mechanistic analysis of flocculation and sedimentation parameters for unclassified gold mine tailings
Wang Jinxing
Yang Han
Yang Xiaolin
Chen Fengbin
Jiao Huazhe
Abstract：Objectives To address the challenges of poor thickening performance and low underflow concentra-tion of unclassified tailings,this study aims to optimize flocculation and sedimentation parameters and ana-lyze 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,floccu-lant 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 de-signed.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 fac-tors 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 sig-nificant 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 floccula-tion 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 under-flow concentration.
Keywords：unclassified tailingsunderflow concentrationfactor interactionflocculation-sedimentation model
Publication Date：2025-09-30
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：9( 91-99 )