A method is disclosed for producing inorganic crystalline base exchange materials having high total exchange capacities and specific initial exchange rates which yield well-defined residual concentrations for the elements of Group II of the Periodic Table. The method of the invention includes the concept of controlling the rate of the addition of the reactants and other reaction variables to prevent gel structure formation and to provide a precipitate of discrete particles with a preoriented array of the elements that is predisposed to the final crystalline structure. Recycle of the mother liquor to provide a totally closed system is further disclosed. By preventing the formation of the gel structure it is possible to eliminate cumbersome and costly processing steps and equipment. By varying the precipitation and crystallation conditions, it is possible to control the ultimate crystal size. Recycle allows recovery of the chemical values of the mother liquor and reduces manufacturing cost. Throughput is also significantly increased. Specific and significant process steps include: make-up of the reactants, purification purge of the reactants, precipitation, crystallization, decanting and quench, solids separation and recycle of the mother liquor to provide the closed system. Recycling includes concentration and desalination. The method of the invention further includes particularly unique processing steps comprising solids separation and countercurrent washing.