Abstract: The invention relates to a method for the treatment of an impure aluminium oxide so that the organic impurities present therein it are converted into an insoluble and easily separable substance. According to the invention, aluminium oxide which contains organic matter as impurities is finely ground, the finely ground aluminium oxide is dissolved at an elevated temperature in sulphuric acid which has a concentration of at minimum 90% by weight, the amount of the sulphuric acid being at least stoichiometric in relation to the amount of aluminium oxide, the organic matter being carbonized into an insoluble and easily separable substance, and, if desired, the obtained mixture is treated further in order to form a solution-form or solid chemical which contains aluminium.

Abstract: The invention relates to a process of preparing ferric sulfate by forming a slurry which contains ferrous sulfate and sulfuric acid, the slurry containing bivalent iron in both the solution phase and the solid phase, and by oxidizing this slurry to form a ferric sulfate slurry. When so desired, the obtained ferric sulfate slurry is solidified to form solid ferric sulfate. The obtained ferric sulfate may, as such or dissolved in water, be used for the treatment of waste waters or for preparing pure tap water.

Abstract: The invention relates to a process for the preparation of hydrogen peroxide by the anthraquinone process, comprising the oxidation of a hydrogenated organic working solution for the formation of hydrogen peroxide and the extraction of the hydrogen peroxide into an aqueous phase, the oxidation and the extraction being carried out in the same space by directing into one and the same reactor (1) a hydrogenated organic working solution, an oxygen-containing gas and an aqueous extraction solvent in order to form a mixture of three phases, i.e., an organic phase, a gas phase and an aqueous phase, whereby the dissolving of the oxygen in the working solution and the oxidation reaction in the working solution, as well as the transfer of the hydrogen peroxide to the aqueous phase are achieved, whereafter the product leaving the reactor is subjected to phase separation (2) for the recovery of an aqueous solution of hydrogen peroxide.

Abstract: The invention relates to a method for producing hydrogen peroxide by the anthraquinone process, by feeding into the top part of a fixed bed reactor (4) hydrogen (3) and a working solution (1), i.e. an anthraquinone derivative in an organic solvent, and by making these infed substances flow downwardly in the reactor, in order to catalytically hydrogenate the anthraquinone derivative owing to the influence of the catalyst bed (6) and by removing the hydrogenated working solution (9) from the reactor. According to the invention, there is used a fixed bed reactor provided with a stationary catalyst bed that has an open structure.