Abstract: An offretite metalloalluminosilicate composition, including an aluminosilicate framework containing at least one metal selected from the group consisting of iron, divalent elements and combinations thereof, wherein at least a portion of the metal is incorporated into the framework, and wherein the portion is at least about 0.5% wt. with respect to the composition.

Abstract: A method for preparing a modified kaolin clay, includes the steps of providing a kaolin clay material having a starting ratio of silica to alumina; mixing the kaolin clay material with acid so as to form a substantially homogenous paste; calcining the paste so as to provide a calcined acid-treated clay material; mixing the calcined acid-treated clay material in water so as to form a suspension; precipitating aluminum from the suspension so as to produce a reduced aluminum suspension; and obtaining a modified clay material from the reduced aluminum suspension, wherein the modified clay material has a final ratio of silica to alumina which is higher than the starting ratio.