Kernforschungsanlage Julich Gesellschaft MIT Beschrankter Haftung

Vereinigte Aluminum-werke Aktiengesellschaft

Gunther Winkhaus

Erich Zimmer

Ahmad Nafissi

The red mud by-product of the Bayer process by which aluminum oxide is reed from bauxite as an aluminate, is digested with concentrated sulfuric acid or with sulfur trioxide gas to produce sulfates that can be leached out to the resulting mass with water. The solution is then heated at a pH of 1 to precipitate titanium oxide hydrate by hydrolysis. The remaining sulfates of the solution are then obtained in solid form by evaporation, or by precipitation with acetone, and the solid is then roasted to convert the aluminum and iron to the oxide. After leaching out the sodium sulfate with water, the aluminum and iron oxide are separated by the Bayer process, which works in this case even though x-ray diffusion patterns show that the aluminum oxide is mainly .alpha.Al.sub.2 O.sub.3.

Growing community of inventors

Konigswinter, Germany

Gunther Winkhaus