Aluminum hydroxycarbonate gel

Process for the continuous production of aluminium hydroxycarbonate gel for use in the formulation of orally-administered antacids comprising adjusting the pH in a first vessel of an acid-reacting aqueous solution of an aluminum salt having an initial pH of less than about 3 by mixing it with an aqueous alkaline solution containing carbonate and bicarbonate anion to obtain a clear reactant aluminum salt solution of pH about 3.5 to about 4, withdrawing the clear reactant aluminum salt solution from the first vessel and transferring it to a second vessel wherein the clear reactant aluminum salt solution is continuously reacted with an aqueous alkaline solution containing carbonate and bicarbonate anion in which the reaction in the second reactor vessel is conducted at a pH of about 6.8 to about 7.5, to obtain an aluminum hydroxycarbonate gel precipitate, continuously withdrawing the reaction mixture and passing it to a third vessel and permitting the gel-forming reaction to proceed to completion wherein the gel-forming reaction in the third vessel is conducted at pH about 6.0 to about 7.0, recovering the gel precipitate from the reaction mixture and removing non-aluminum cations from the gel precipitate within such time that on average the gel precipitate is in contact with the reaction products containing non-aluminum cations for a period of no more than about 6 hours after the gel precipitate is completely formed.