Water-Soluble Polymer Depressants in Froth Flotation

从矿石中提取金属，需要将矿石中的含金属矿物分离提纯成单个的精矿。目前大多数矿物分离都是通过泡沫浮选来完成的，泡沫浮选是根据矿物的表面疏水性来分离矿物的。疏水矿物像油滴一样浮在水中，而亲水矿物则留在水中。然而，当亲水性矿物的粒度非常小（<~10微米）时，它们可以被夹带到精矿中，降低了分离效率。此外，许多有毒的无机试剂，如氰化钠、重铬酸钾等，被用来将贱金属矿物分离成单个精矿。解决这两个问题的一个潜在有效的解决方案是使用聚合物抑制剂，它具有低毒性或无毒性，还可以增加颗粒尺寸，从而恢复分离效率。聚合物试剂的一个关键要求是，它们可以选择性地作用于矿石中的某些矿物质，而不是所有矿物质。这可以通过在聚合物中加入不同的官能团来实现。对聚合物试剂的另一个要求是它们是良好的絮凝剂。我们最近观察到，后者似乎取决于聚合物溶液的制备方式。文献中关于聚合物溶液制备及其絮凝性能的信息相互矛盾。拟议的项目旨在解决这两个问题。它包含两个子课题：(1)壳聚糖与磷酸或黄药基团接枝；(2)聚合物溶液老化对聚合物絮凝活性的影响。由于矿产资源的金属开采是加拿大经济的主要贡献者之一，因此研究结果将使加拿大受益。

Metal extraction from ores requires that the metal-bearing minerals in the ores be separated and upgraded into individual mineral concentrates. Most of the mineral separation today is done by froth flotation, which separates minerals based on their surface hydrophobicity. Hydrophobic minerals are floated (like oil drops) to a concentrate while hydrophilic minerals stay in water. However, when the particle sizes of the hydrophilic minerals are very small (<~10 micron), they can be carried to the concentrate by entrainment, lowering separation efficiency. Also, many toxic inorganic reagents such as sodium cyanide, potassium dichromate, etc., are used to separate base metal minerals into individual concentrates. A potentially effective solution to counter both problems is to use polymer depressants, which have low or no toxicity and can also increase particle size, thus restore separation efficiency.One of the key requirements for the polymer reagents is that they selectively act on some minerals but not on all minerals in the ore. This can be achieved by incorporating different functional groups in the polymers. The other requirement for the polymer reagents is that they are good flocculants. We recently observed that the latter seems to depend on how the polymer solution is prepared. Literature contains contradictory information on polymer solution preparation and its flocculation performance. The proposed project is aimed at addressing these two issues. It contains two sub-projects: (1) grafting chitosan with phosphate or xanthate groups, (2) effect of ageing of polymer solutions on the flocculation activity of the polymers. The research results will benefit Canada as metal extraction from mineral resources is one of the major contributors to Canadian economy.