Chloro hypochlorite;zirconium → Zirconium carbonate

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With respect to the above process, preferably, prior to the heating step, the zirconium oxychloride and soda ash are agitated or mixed by other means to form a solution mixture preferably at ambient temperature, such as room temperature (e.g., from about 40° F. to about 110° F.). With regard to the metastable sodium zirconium carbonate solution which is achieved prior to the heating step, preferably, a gelatinous precipitate of zirconium carbonate is formed when zirconium oxychloride (solution or solid) is added to soda ash solution. Due to the amphoteric property of the material, the zirconium carbonate re-dissolves in excessive soda ash solution to preferably form a metastable sodium zirconium carbonate (alkaline) solution at room temperature. When the mixing ratio of ZrOCl2.8H2O to soda ash is optimized and the mixing temperature is preferably maintained in the range of from about 90° to about 95° F. (by the heat of reaction generated during mixing), the material is preferably completely dissolved to form a clear solution. Upon storage at room temperature for a few hours, the solution becomes turbid as precipitate starts to form. The turbidity of the starting solution does not affect the particle size and % recovery of the product. Nevertheless, it is preferred to start heating up the metastable SZC solution at once after it is formed. In the heating step, precipitation of SZC preferably starts to occur at about 150° F. due to saturation. As heating is continued, polymeric SZC particles start to grow to 30–50 micron particle size range at the final temperature (boiling point) of the sodium zirconium carbonate. Preferably, a sufficient temperature is the boiling temperature of the mixture of the zirconium oxychloride and soda ash. For example, the temperature of the heating can be from about 150° F. to about 250° F. (super heating under pressure) for a time of about 2 hours. The equilibration time at the final temperature is about 2 hours. Maximum temperature of heating and long heating time affect the resulting particle size. When heating sodium zirconium carbonate and the soda ash, preferably the heating rate of the mixture is from about 0.5° F. to about 1° F./minute until boiling of the mixture is achieved. The mixture can be heated until the superheating temperature of the mixture is obtained under pressure.

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