Magyar Aluminiumipari Troszt

Zoltan Osvald

Gyula Horvath

Karoly Solymar

Janos Steiner

Gyorgy Kaptay

Gergely Veres

Gyula Odor

Gyorgy Lang

Zoltan Felfoldi

Gyorgy Dobos

The invention relates to plant operations for increasing the cycle times of heat exchangers by the digestion of the aluminium oxide content of a slurry according to the Bayer technology, said slurry consisting of bauxite and sodium aluminate liquor, using an equipment in which the material is heated stepwise and in more parallel material streams, then the material streams are combined and further heated, or combined and kept at the same temperature, or after combination further heated and kept at the same temperature, characterized in that a part of the parallel material streams is slurry, another part of same is aqueous sodium hydroxide solution, preferably sodium aluminate liquor containing sodium hydroxide, or water, and the parallel material streams are exchanged in the heat exchangers in a cyclical manner.

Cleaning boiler tubes of digesting heat exchangers used in alum earth

Disclosed is a method for the treatment of the red mud byproduct of the Bayer aluminum process, wherein limestone, hydrated lime or other CaO-containing material is added to the red mud in certain molar proportions to the ingredients of the red mud, then the mixture is further mixed with a reducing agent, and the entire mixture is subjected to a reducing heat treatment during the course of which the mix becomes softened or molten. The iron and the slag are separated from each other while the mix is still molten, or after it has been cooled, and then the Na and Al-content of the slag is extracted with a sodium carbonate solution containing a caustic, or with a sodium carbonate solution and a solution of a caustic in two steps.

Method for the treatment of red mud

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Budapest, Hungary

Zoltan Osvald