煤泥水中Ca^(2+)在黏土矿物表面的作用

Calcium ions adsorption mechanism on clay particles surface in coal slurry

为了深刻认识煤泥水中Ca2+同黏土矿物颗粒之间的相互作用,笔者用Ca2+溶液在不同pH值条件下分别同高岭土和蒙脱土作用,测定黏土作用前后的X-射线衍射、红外光谱和X-射线光电子能谱.实验证实了在pH=5.0溶液中Ca2+在黏土表面以静电形式吸附;在pH=11.0溶液中Ca2+以Ca(OH)2沉淀和静电形式吸附;此外,在pH=8.0以上的溶液中还可能存在一羟基络合吸附形式.提出了Ca2+沉淀吸附和一羟基络合吸附的吸附过程模式;黏土颗粒表面的Ca(OH)2沉淀使颗粒间形成的非选择性“静电桥”是影响沉降和浮选效果的原因之一.

In order to study the adsorption mechanism of calcium ions on clay particles, kaolin and montmorillonite were individually soaked in calcium solution which pH value were 5.0 and 11.0, then separated, oven dried, and analyzed through XPS, FHR and XRD. Experiment results show that the adsorption form is ion electrostatic adsorption when solution pH value was 5.0, Ca （OH） 2 precipitation and ion electrostatic adsorption when pH value is 11.0. In addition, complexion adsorption may exist when pH value is more than 8.0. The processes of precipitation adsorption and complexion adsorption were presented. Non-selectivity “ion electrostatic bridge” between particles arose from Ca （OH）2 precipitation is one of the factors which affected on floatation and deposition.