Patent ID: 8318129

Claim:
A method for producing a hydrotalcite of the Formula: Mg 1-x Al x (OH) 2 ( A n− ) x/n .{(1 −a )(1-3 x /2)− a·z /18}H 2 O (I) said method comprising heating a hydrotalcite of Formula (II): Mg 1-x Al x (OH) 2 ( A n− ) x/n .(1−3 x/ 2)H 2 O (II) at a temperature range from 160° C. to 220° C. to reduce the weight of hydrotalcite of Formula (II) by 2 to 3.52% to produce the hydrotalcite of Formula (I), wherein A n− is an anion selected from the group consisting of CO 3 2− , NO 3− , SO 4 2− , OH − , F − , Cl − , Br − and an oxoanion comprising Si, P or B; z is the formula weight of Mg 1-x Al x (OH) 2 (A n− ) x/n ; x is in the range of 0.20<x≦0.33; and a is in the range of 0.02≦a 0.0352.