ES208650A3 - A process for the obtaining of aluminum suitable for the electrometallurgy of aluminum from caolines or clays poor in iron and sodium sulfate, with simultaneous obtaining of sulfide acid and caustic soda (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

A process for obtaining alumina suitable for the electrometallurgy of aluminum from kaolins or clays poor in iron and sodium sulphate with simultaneous obtaining of sulfuric acid and caustic soda essentially consisting of attacking the first clay or kaolin matter if it is necessary to previously calcined with hydrochloric acid only or accompanied by a certain proportion of sulfuric acid according to the composition of alumina silicates in the clay, aluminum chloride in concentrated solution and some aluminum sulphate are obtained in this attack, which in a second phase of the process are treated with the stoichiometric proportion of sodium sulphate obtained by double reaction aluminum sulfate and sodium chloride that precipitate spontaneously by mass effect completing if necessary its insolubilization by concentration. Then the solution of aluminum sulfate impurified with some iron sulphate from the oxide that impurifies the clays is treated with potassium sulfate, which precipitates a potassium alum with a large number of water molecules of crystallization. The precipitate is separated by filtration and finally subjected to a stepped calcination in one of whose stages the aluminum sulfite of the complex is decomposed leaving alumina releasing sulfuric anhydride and leaving unchanged the part of potassium sulfate that is part of the complex. Finally in the cycle in the corresponding phase of the process. Finally, the alumina or its corresponding previously dried hydrate is able to be expanded as such or subjected to the known processes of electrometallurgy of aluminum. (Machine-translation by Google Translate, not legally binding)