煤泥浮选过程中黏土矿物罩盖及其行为调控

Clay coating and its behavior regulation in fine coal flotation

为探索微细粒黏土矿物在煤泥浮选过程中的罩盖行为,进一步回收利用稀缺的炼焦煤资源,以钱家营选煤厂灰分为49.3%的浮选中煤为研究对象,进行了螺旋抛尾和磨后浮选试验。结果表明,当要求精煤灰分为12.5%时,螺旋粗精煤磨煤3.5 min后可获得最高的精煤产率,高灰细粒黏土矿物的罩盖是精煤灰分不达标的主要原因。根据对煤-黏土颗粒体系相互作用势能计算分析,提出通过改变静电力和范德华力2种调控手段降低黏土矿物的回收率,但调控静电力抑制浮选过程细泥罩盖与细泥沉降浓缩又存在着难以调和的矛盾,通过在疏水性煤颗粒表面引入纳米气泡层,进而改变体系的Hamaker常数,使得通过调控范德华力来降低黏土矿物的罩盖成为可能。

In order to explore the flotation behavior of ultra- fine clay and make full use of scarce coking coal,the flotation middlings with49. 3% ash content collected from Qianjiaying Coal Preparation Plant and the process of tailings discarding by spiral separator integrate with grinding- flotation was carried out in the present paper. The results showed that the maximum yield with 12. 5% ash content was obtained when 3. 5 min grinding time was adopted. The high ash content concentrated were mainly attributed to the ultra- fine clay minerals coating. According to the calculation of inter- particle potential for coal- clay system,two regulation methods were proposed by modulating the electrostatic force or van der Waals force to lower the clay recovery. It should be noted that the inhibition of the clay coating was contradict with the effective slime settlement. Nevertheless,the introduction of nanobubble layer may be the appropriate way to control the clay coating in future,because of the considerable change of the system Hamaker constant.