氧肟酸高分子药剂在铝土矿反浮选中的作用

Effect of Hydroxamic Acid Type High Molecular Reagents in Reverse Flotation of Bauxite

通过浮选试验 ,研究了氧肟酸淀粉和氧肟酸聚丙烯酰胺两种高分子药剂对铝土矿中一水硬铝石和高岭石浮选行为的影响。结果表明 :氧肟酸淀粉在酸性条件下对一水硬铝石有较强的抑制作用 ,而对高岭石有活化现象 ;氧肟酸聚丙烯酰胺在整个试验 pH值范围内对两种矿物均有活化作用。两种大分子药剂属于阴离子型 ,动电位测定结果表明 ,它们在带负电的高岭石、一水硬铝石表面吸附 ,使其动电位负性增加 ,表明药剂与矿物存在氢键力或化学作用力。由于在一水硬铝石表面 ,氧肟酸淀粉可以罩盖捕收剂十二胺 ,增加矿物表面的亲水性 ,从而对其产生抑制作用。而线型氧肟酸聚丙烯酰胺在矿物表面为卧式吸附 ,其分子链上的负电区能够增加阳离子捕收剂的吸附量 ,从而活化了一水硬铝石的浮选。

The effect of two high molecular reagents, hydroxamic acid starch (HAS) and hydroxamic acid polyacrylamide (HPAM) on diaspore and kaolinite in bauxite is studied through flotation tests. The results show that, under acidic condition, HAS has strong depression effect on diaspore and activation effect on kaolinite, while HPAM has activating effect on both minerals in the whole pH range in the tests. Both the large molecular reagents are of anionic type. The electrokinetic potential measurement results show that they can adsorb on the negative charged surfaces of kaolinite and diaspore to increase their negative electrokinetic potential, showing a hydrogen bonding force or chemical force between the reagents and the minerals. Due to its ability to cover the dodecylamine collector on the surface of diaspore to increase the hydrophicility of the mineral surface, HAS can produce depression effect on diaspore. The linear HPAM adsorbs on the mineral surface in a horizontal way and the negative charged area in its molecular chain can increase the adsorption of cationic collector. As a result, it activates the flotation of diaspore.