PURAL MG 70

The collected and refined know-how to produce alumina hydrates via the sol-gel technique is used by Sasol to prepare other inorganic oxides or mixed oxides. The properties of these inorganic specialty materials are leading Sasol into new, interesting fields of research and application. One of these specialties is the hydrotalcite family (aluminium-magnesium compounds) which is obtained by hydrolysis of mixed alcoholates. Compared to alumina hydrates, hydrotalcites are even more alkaline in nature. Basicity is adjustable by increasing the Mg/Al ratio and/or incorporating anions other than OH-. Hydrotalcites have a double-layered metal hydroxide structure. The layers consist of magnesium and aluminium hydroxide octahedra sharing edges. Additional interstitial anions between the layers compensate the charge of the crystal and determine the size of the interlayer distance (basal spacing). While hydrotalcites are accessible through the corresponding metal salts, the metal alcoholate route, patented by Sasol, has advantages over other synthesis routes. Most important is that the Al/Mg ratio can be varied over a wide range. In addition, it is now possible to obtain hydrotalcites with a purity and a controlled anion content that have to date been unavailable.