Aluminum hydroxide gel, process for production thereof, and use thereof

Claim 1

An amorphous aluminum hydroxide gel of formula (I) in which Ca and/or Mg are bonded to the compound of formula (I) by ion-exchange with an alkali metal, (CaO, MgO, M.sub.2 O).sub.x.Al.sub.2 O.sub.3.(CO.sub.2).sub.y.mH.sub.2 O (I) wherein M represents an alkali metal, M 2 O may be zero, CaO and MgO are not zero at the same time and x, y and m are positive numbers represented by the following expressions 0.1≦x<0.8, 0.4≦y≦0.8, 2≦m<10 said amorphous aluminum hydroxide gel being produced by the process which comprises reacting an aluminum compound soluble in water and/or lower alcohols selected from the group consisting of aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum metal, aluminum ammonium sulfate, aluminum bromide, aluminum fluoride, aluminum potassium sulfate, aluminum isopropoxide, sodium aluminate, potassium aluminate, and aluminum sodium sulfate, with a carbonate ion yielding compound soluble in water and/or lower alcohols selected from the group consisting of sodium carbonate, potassium carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate, at a pH of about 6 to about 9.5 under such conditions that the CO 2 /Al mole ratio of the resulting aluminum hydroxide gel is about 0.1-about 8, and ion exchanging the alkali metals of the resulting compound with magnesium and/or calcium.