Other

Zoltan Ozvald

Karoly Solymar

Jozsef Matyasi

Istvan Voros

Tibor Ferenczi

Janos Zambo

Peter Siklosi

Laszlo Lengyel

Pal Toth

Tihamer Pinter

Ivan Feher

Kalman Wentzely

Ferenc Lazar

Gyorgy Sigmond

Erno Bujdoso

Marika Orban Nee Kelemen

A method for processing bauxites according to the Bayer technology, with an increased yield in Al.sub.2 O.sub.3 and with decreased caustic soda losses, starting particularly from goethite bauxites of boehmite and/or diaspore type and carrying out the digestion at 180.degree.C to 300.degree.C using an aluminate liquor containing Na.sub.2 O.sub.caustic in a concentration of 80 to 300 g./l. The digestion is carried out in the presence of a calcium compound in an amount corresponding to 2 to 6 % of CaO calculated for the dry weight of bauxite and of a sulfate salt in an amount corresponding to 1.0 to 7.0 g./l. of sulfate ion concentration, whereby the goethite content of the bauxite is converted into hematite. The process provides advantageous conditions for the complete dissolution of the boehmite and diaspore content of bauxite in the vicinity of the equilibrium molar ratio, and enables to recover efficiently the caustic soda losses in the Bayer process itself, requiring no supplementary operation.

Method for processing bauxites

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Budapest, Hungary

Zoltan Ozvald