| 摘要 |
A method of producing an aluminium-sulphate solution, in which an aluminum-hydroxide containing raw naterial, particularly products from the Bayer process or bauxite, is admixed with an aqueous sulphuric-acid solution whilst digesting the raw material, to form an aluminium-sulphate solution. The invention is characterized in that a stream of gas is blown through the aqueous sulphuric-acid solution, at least while charging the major part of the raw material. The amount of gas is selected to be sufficient to remove from the solution the water vapour formed during the reaction. Foaming will thereby be substantially eliminated during the digesting process. The gas is selected, with respect to its reduction ability, so that no substantial reduction of any Fe(III)-ions released during the digesting process takes place. In a preferred embodiment, digesting is effected in an inverted conical vessel (1). |
