The present invention provides improved methods for producing the aluminum adjuvant AlPO 4 . In one aspect, the present invention provides a method for producing aluminum phosphate which comprises the steps of mixing a solution of aluminum chloride and a solution of sodium phosphate tribasic to produce an aluminum phosphate precipitate, wherein the improvement comprises settling the aluminum phosphate precipitate at a temperature in the range of about 50 °C to about 70 °C. In another aspect, the present invention is directed to methods for producing aluminum phosphate within a closed system.