Two powder synthesis of hydrotalcite and hydrotalcite like compounds

摘要

There is provided an improved method for making synthetic hydrotalcite by first reacting a divalent metal compound with a trivalent metal oxide powder in a carboxylic acid-free, aqueous solution or suspension to form an intermediate. This intermediate is then contacted with an anion source such as carbon dioxide; a carbonate-containing compound; an acid or an ammonium salt to form a layered double hydroxide having the formula: A1-xBx(OH)2Cz.mH2O, where A represents a divalent metal cation, B represents a trivalent metal cation, C represents a mono- to polyvalent anion, and x, z and m satisfy the following conditions: 0.09<x<0.67; z=x/n, where n=the charge on the anion; and 2>m>0.5. Said layered double hydroxide is typically separated from the suspension by filtering, centrifugation, vacuum dehydration or other known means.