Zeolites form an important class of inorganic materials with an enormous industrial interest, which derives from their molecular sieving, ion-exchange and catalytic properties. The use of Zeolite NaA in laundry detergents by replacing phosphates and in the field of metallic waste treatment is increasing. In the present investigation, Zeolite NaA is synthesized from low-grade Indian china clays. The technique of clay conversion to Zeolite depends on a number of parameters influenced by the origin, physicochemical nature and composition of the clays. In the present work, three different grades of china clay were used to prepare Zeolite NaA. The Zeolites prepared from these three grades of china clay have different CEC values of 218, 221 and 206 mg CaCO₃/g Zeolite respectively. It was noticed that the properties of synthetic Zeolite were also affected by the reactant mole ratio. Higher Al₂O₃ concentration favors low silica Zeolite formation. Further, it was noticed that on increasing the alumina concentration, the stability of Zeolite NaA increases, i.e., its conversion to other Zeolites is retarded, but increase in alkali concentration favors the hydroxysodalite formation.

Zeolites are playing an ever-increasing role in the era of environmental awareness and regulation. Zeolite NaA, a water insoluble crystalline hydrated alumino-silicate of a group I element in its sodium form, has recently been introduced in extensive quantities as a builder in detergents in the field of metallic waste treatment. The Zeolite demand by detergent manufactures is increasing rapidly. The most important reason is the necessity to reduce or eliminate the eutrophication of rivers and lakes caused by poly-phosphates, for which many countries have developed or are developing legislative voluntary regulations for the reduction or the total ban of phosphates in laundry detergents (Greek and Layman, 1989; and Bhatt, 1995). Zeolite is a raw material for detergents; its per unit cost should be low enough to complete the sodium tripolyphosphate and other chelating agents. Thus it is necessary to produce the synthetic Zeolite from a cheap raw material source utilizing a technique or process requiring low energy and other utilities, and thus resulting in lower production cost. Clays are such type of raw materials, and production of Zeolites from clay as a source of alumina and silica is being continuously investigated with positive results (Chandrasekhar and Pramada, 1999; Chaudhuri et al., 2002; Aderemi, 2004; Atta et al., 2007; and Baojian et al., 2009). Processing techniques for the conversion of natural clays to Zeolites that are used for the gel process are different and depend on a number of factors, which are influenced by the origin, physicochemical nature and composition of the clays.

Chemistry Journal, Zeolites, Catalytic Properties, Hydroxysodalite Formation, Metallic Waste Treatment, Processing Techniques, Sodium Tripolyphosphate, Hydrothermal Crystallization, Thermal Dehydration, Chelating Agents, Gel Process, Crystallization.