超细全尾砂深锥动态絮凝浓密试验

Deep cone dynamic flocculation thickening of ultrafine full tailings

为探明超细全尾砂的浓密特性,开展量筒沉降实验,小型和半工业深锥动态浓密试验.结果表明,分子量1200万的非离子型絮凝剂最利于尾砂沉降,随絮凝剂单耗增加,溢流浊度降低,底流浓度基本不变.随固体通量增加,溢流浊度增加,底流浓度降低.固体通量0.4 t·m^(−2)·h^(−1),给料固体质量分数12%,絮凝剂单耗50 g·t^(−1)的最佳参数条件下,小型和半工业动态浓密试验的底流平均固体质量分数分别为62.8%和74.4%,泥层高度对底流浓度影响显著.深锥浓密机底流固体质量分数随泥层高度增加呈DoseResp函数增长,分为缓慢增长(泥层1~4 m)、快速增长(泥层4~7 m)和基本稳定(泥层超过7~8 m)3个阶段,这跟尾砂絮团在不同泥层高度下的压缩性能有关.可根据底流浓度与泥层高度的函数关系,调节泥层高度来满足井下充填所需底流浓度.

In the future,the output of ultrafine full tailings will explode due to the massive mining of low-grade deposits and demand for the recovery of useful minerals.The best way to dispose of ultrafine full tailings is to prepare them into the paste for filling underground voids or surface stacking.The deep cone thickening of ultrafine full tailings is a key link of tailings paste disposal technology.In the thickening process of ultrafine full tailings,slow sedimentation velocity,high dosage of flocculant,excessive overflow turbidity,and low underflow concentration are the bottlenecks that restrict the application of disposal technology for ultrafine full tailings paste.To investigate the thickening characteristics of ultrafine full tailings,the sedimentation test in measuring cylinder,the small-scale and semi-industrial deep cone dynamic thickening tests were carried out.Results show that the nonionic flocculant with a molecular weight of 12 million is most beneficial for the settlement of the tailings.With increasing flocculant dosage,the turbidity of overflow decreases and underflow concentration remains unchanged.Upon increasing the solid flux,the turbidity of overflow increases and underflow concentration decreases.In particular,when the solid flux is 0.4 t·m^(−2)·h^(−1),the feeding solid mass fraction is 12%,flocculant dosage is 50 g·t^(−1),and average solid mass fraction of the underflow of the small-scale and semi-industrial dynamic thickening test is 62.8%and 74.4%,respectively.Mud height has a significant influence on the underflow concentration.The solid mass fraction of the underflow of the deep cone thickener increases with the increasing mud height,and this process conforms to the DoseResp function.This growth process can be divided into three stages:(1)slow growth(mud height 1-4 m),(2)rapid growth(mud height 4-7 m),and(3)basic stable(mud height over 7-8 m).This is related to the compression performance of the tailings flocs at different mud heights.According to the function relation between the underflow concentration and mud height,the mud height can be adjusted to meet the required underflow concentration for underground backfilling.