煤及高岭石的选择性絮凝

为考察选择性絮凝-浮选中絮凝剂对煤与高岭石的选择性作用，研究了絮凝剂聚丙烯酰胺在煤及高岭石表面的吸附等温线及吸附量差值。使用激光粒度分析仪测试了煤和高岭石在不同聚丙烯酰胺作用下所形成絮体的表观粒径分布，并计算了聚丙烯酰胺分子的流体力学半径和吸附半径以讨论其空间吸附构象。研究表明，煤对阴离子型聚丙烯酰胺的吸附量高于高岭石，且吸附量差值随分子量的增大而减小，高岭石对阳离子型聚丙烯酰胺的吸附量高于煤，吸附量差值较小。分子量为3×10 6阴离子型聚丙烯酰胺选择性最好，煤和高岭石对其吸附过程更符合Langmuir吸附模型，质量浓度为12 mg/L时，煤对其吸附量是高岭石的2.15倍，使煤絮体的d10，d50，d90分别为高岭石絮体的8.42，2.60和2.75倍。计算聚丙烯酰胺的吸附半径小于其流体力学半径，其在矿物表面的吸附发生了强度不同的压缩或穿插效应。

Selective flocculation of coal and kaolinite

In order to study the selectivity of flocculant between coal and kaolinite in selective flocculation floatation，the adsorption isotherm and adsorbance difference of polyacrylamide onto kaolinite and coal was investigated.The laser particle size analyzer was used to measure the flocs size distribution of coal and kaolinite in different polyacrylamide solution.Hydrodynamic radius and adsorption radius of polyacrylamide molecular were calculated to discuss its adsorption conformation.The adsorbance of anionic polyacrylamide onto coal is higher than that of kaolinite.The adsorbance difference between coal and kaolinite decreases with the increase of polyacrylamide molecular weight.The adsorbance of cationic polyacrylamide onto kaolinite is higher than that of coal，and the adsorbance difference is lower.Selectivity of anionic polyacrylamide with molecular weight 3×106 is the best.Adsorption process of coal and kaolinite is more accord with Langmuir adsorption model.The coal adsorbance of this polyacrylamide is 2.15 times larger than that of kaolinite.The indicators of particle size distribution，d10，d50 and d90 of coal flocs are 8.42，2.60 and 2.75 times of kaolinite flocs，respectively.The calculated adsorption radius of polyacrylamide molecular is lower than its hydrodynamic radius.When different polyacrylamide is absorbed onto different mineral surfaces，the effect of compression or penetration with different intensity of polyacrylamide occurres.