不同粒径级配尾砂沉降特性的试验研究

Experimental Study on Settlement Characteristics of Tailings with Different Particle Size Grading

为研究粒径级配对尾砂沉降特性的影响,配制了5组不同粒径级配的尾砂,并对各组尾砂浆分别开展静态自然沉降、静态絮凝沉降和动态絮凝沉降试验,对不同浓密方式下的尾砂浆沉降效率和底流质量浓度进行分析。试验结果表明:-200目颗粒含量低于60%时,尾砂沉降速度较快,采用静态自然沉降、静态絮凝沉降和动态絮凝沉降方式均能获得较高的沉降效率和浓密底流浓度。-200目颗粒含量超过60%时,尾砂沉降速度明显降低,泥层界面模糊不清,上层液中含固量较高,尾砂静态自然沉降变得困难,通过添加适量絮凝剂能提高尾砂沉降效率。对于-200目颗粒含量超过80%的超细尾砂,采用动态絮凝沉降方式,能同时获得较高的沉降效率和底流浓度。随着细颗粒含量增多,各组尾砂沉降的最大底流浓度呈逐渐下降趋势。同样粒径级配的尾砂样品,动态絮凝沉降的底流浓度最高,静态自然沉降的底流浓度次之,静态絮凝沉降的底流浓度相对最低。

In order to investigate the influence of particle size grading on the settlement characteristics of tailings,5 groups of tailings with different particle size were prepared.Then the static natural settlement,static flocculation settlement and dynamic flocculation settlement tests were carried out for each group of tailings slurry,and the settlement efficiency and underflow mass concentration of tailings slurry under different thickening modes were analyzed.The test results showed that when the particle content of-200 mesh was lower than 60%,the settlement speed of tailings was fast,and high settlement efficiency and dense underflow concentration can be obtained by static natural settlement,static flocculation settlement and dynamic flocculation settlement methods.When the particle content of-200 mesh was more than 60%,the settlement speed of tailings was obviously reduced,the interface of mud layer was unclear,the solid content in upper liquid was high,the static natural settlement of tailings became difficult,and the settlement efficiency of tailings can be improved by adding proper flocculant.For the ultra-fine tailings with more than 80% of-200 mesh particles,high settlement efficiency and underflow concentration can be obtained at the same time by dynamic flocculation settlement method.With the increase of fine particle content,the maximum underflow concentration of tailings settlement in each group decreased gradually.For the tailings samples with the same particle size grading,the bottom flow concentration of dynamic flocculation settlement was the highest,followed by that of static natural settlement,and the bottom flow concentration of static flocculation settlement was the lowest.