CRYSTALLOCHEMISTRY OF PALYGORSKITE

摘要

That the oxides of Al_2O_3, Fe_2O_3 Fe_2O_3 and MgO are self component of palygorskite same with SiO_2 and CaO, TiO_2, K_2O and Na_2O are adsorpt material. The crystal chemical formule of palygorskite is show as (Mg Al Fe □)_5 Si_8O_(20)(OH)_24H_2OnH_2O, and the liner relation for cations in octahedral belt is Mg~(2+) = 4.978-1.5189(A1~(3+)+Fe~(3+)), then 1.14< Al~(3+)+Fe~(3+)< 2.5. There is only one kind of Fe~(3+) in palygorskite and the occuping model for cations in octahedral side are M_2M_1M_3M_1M_2, M_2 = (Mg~(2+)x) (Fe_(1-x)~(3+)), M_3 = (Al~(3+)) or (Al~(3+)+Fe~(3+)), M, = (Al~(3+)+Fe~(3+)) or Fe~(3+) and □ (empty) octahedronsite. The palygorskites were divided into clayly palygorskite forming from sedimentary and riching in Fe~(3+), and fibrous palygorskite forming from alteration and lowing in Fe~(3+) and riching in Al~(3+).