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.