Purification of halloysite by magnetic separation

Rational use of mineral resources requires advanced separation methods in order to obtain high quality products. In this study chemical treatment with magnetic separation of halloysite from Dunino (Poland) is presented. Initial crushing, hydrochloric acid absorption treatment, sedimentation (settling) and polygradient magnetic separation in weak magnetic field were applied to separate aluminosilicates from iron and titanium oxides (impurities). The process allowed to obtain a product of approximately 98% purity of the aluminosilicate fraction (halloysite + kaolinite). The tailings from magnetic separation consisted of iron oxides, while the intermediate product consisted mainly of aluminosilicate and iron chlorides resulting from the HCl treatment. The obtained products can be used as a component of polymer nanocomposites, sorbents and in ceramics industry.