Amorphous kaolin derivative and process for preparing an amorphous derivative of one of the minerals of the kaolin group

摘要

PCT No. PCT/AU94/00323 Sec. 371 Date Jan. 17, 1996 Sec. 102(e) Date Jan. 17, 1996 PCT Filed Jun. 16, 1994 PCT Pub. No. WO95/00441 PCT Pub. Date Jan. 5, 1995Amorphous derivatives of kaolin group minerals characterized by high specific surfaces and/or high cation exchange capacities and a 27AL MAS NMR spectrum having a dominant peak at about 55 ppm relative to Al(H2O)63+. Such derivatives are prepared by reacting a kaolin group mineral with a reagent, such as, an alkali metal halide or an ammonium halide which converts the majority of the octahedrally coordinated aluminum in the kaolin group mineral to tetrahedrally coordinated aluminum. Such derivatives show high selectivity in its cation exchange towards the metals: Pb2+, Cu2+, Cd2+, Ni2+, CO2+, Cr3+, Sr2-, Zn2+, Nd3+ and UO2+.