基于上澄清液浊度的超细尾砂絮凝沉降试验

Flocculation Sedimentation Test of Ultrafine Tailings Based on Turbidity of Supernatant Liquid

为解决现有超细尾砂浓密沉降试验不考虑上层清液浊度的问题,提出了一种超细尾砂浓密沉降的絮凝剂优选方法。以某萤石矿超细尾砂为研究对象,以预制尾砂浆浓度、絮凝剂类型和絮凝剂掺量作为因变量,测试不同沉降时间下上澄清液浊度,并综合考虑沉降速度和絮凝剂成本,获得不同预制尾砂浆浓度下的最佳絮凝剂类型和掺量。试验结果表明:当预制尾砂浆浓度分别为5%、8%、11%和14%时,最佳絮凝剂类型分别为1800万、1600万、1600万和1200万阴离子聚丙烯酰胺,最佳絮凝剂掺量分别为15,25,30,30 g/t。试验结果为该矿山的超细尾砂浓密沉降工程参数提供了依据。

A set of measuring cylinders is generally used to carry out sedimentation test in the dense dewatering of the whole tailings,and the sedimentation velocity and sedimentation underflow concentration of the tailings are used as the basis of flocculants optimization. However,the dense dewatering of ultra-fine tailings has the characteristics of difficult settling and slow settling speed. The turbidity of the supernatant is an important criterion for the selection of flocculants.The currently widely used experimental methods for dense dehydration of full tailings are difficult to meet the dense dewatering of ultra-fine tailingsIn order to solve the problem that the turbidity of supernatant liquid is not considered in the existing dense sedimentation test of ultrafine tailings,a flocculant optimization method for dense sedimentation of ultrafine tailings was proposed.Taking the ultra-fine tailings of a fluorite mine as the research object,and taking the concentration of prefabricated tailings slurry,the type of flocculant,and the amount of flocculant as the dependent variables,a comprehensive test was carried out,and the mixing of tailings slurry and flocculant was carried out in a six-stage mixer. Mixing,reacting and precipitation,using a turbidimeter to test the turbidity of the supernatant liquid at different settling times,and comprehensively considering the settling speed and the cost of the flocculant,to obtain the optimal type and dosage of flocculant under different concentrations of prefabricated tailings.The experimental results show that:For the flocculation and sedimentation of ultra-fine tailings with both bridging and protective effects of flocculants,when the concentrations of prefabricated tailings are 5%,8%,11% and 14%,respectively,the optimum flocculant types are 18 million,16 million,16 million and 12 million anionic polyacrylamide,and the optimal flocculant dosage is 15,25,30 and 30 g/t respectively.Among them,the turbidity of the tailings slurry with the concentration of 8%,11% and 14% change obviously after using the optimal molecular weight and dosage of the flocculant,which could be reduced by more than 10NTU,but the difference is not large.Considering the flocculant price,we recommend the mine use 14% as the feed concentration of the mine’s deep cone thickener.The experimental results provide the basis for the dense settlement engineering parameters of the ultra-fine tailings in this mine,indicating that the ultra-fine tailings dense dewatering experimental method and flocculant selection method proposed in this paper have good application prospects.