Abstract: A window transparent to electron rays is provided which includes a foil which is transparent to electron rays and an element for supporting a peripheral region of the foil in an operational state. The element is made from a material having a greater linear thermal expansion coefficient than the foil material. The window transparent includes an intermediate layer between the foil and a retaining element. The retaining element acts as a support element and consists of a material having a linear thermal expansion coefficient which is equal or similar to the linear thermal expansion coefficient of the foil material and smaller than the linear thermal expansion coefficient of the material of the retaining element over a processing temperature range. A method of manufacturing a window which is transparent to electrons and an X-ray device with a window transparent to electrons are also provided.

Abstract: The invention relates to a window transparent to electron rays comprising a foil (1; 101) which is transparent to electron rays and an element (2; 102) for supporting a peripheral region (1a, 1b) of the foil transparent to electron rays in the operational state, which element is made from a material having a greater linear thermal expansion coefficient than the foil material, with an intermediate layer (4; 104a, b) which is arranged between the foil (1; 101) and a retaining element (2; 102) acting as a support element and which consists of a material having a linear thermal expansion coefficient which is equal or similar to the linear thermal expansion coefficient of the foil material and smaller than the linear thermal expansion coefficient of the material of the retaining element, seen over the processing temperature range.

Abstract: A method of recovering a metallic aluminum from an aluminum-containing slag of an aluminum smelting process. In this method, the slag is crushed a number of times with each crushing product being separated by a screening off removing the metallic aluminum before the next crushing stage. Water-soluble components are then removed from the slag by leaching and the leaching solution is evaporated to enable recovery of these components.

Abstract: In a process of producing coarse pure potassium chloride crystals from feed solutions containing potassium chloride and other impurities, comprising cooling the solution under a vacuum in a plurality of stages connected in series, withdrawing by means of a conveyor the potassium chloride which has been crystallized in each stage, withdrawing the water vapors, collecting crystalline potassium chloride from the solution, drying the crystalline potassium chloride and separating the same into several fractions, compacting the fine fraction and cooling and aminating the end product, the potassium chloride content of the feed solution is increased in that potassium chloride from one or more of the stages containing solution at a low temperature is recycled to the feed solution before the latter enters the first stage.

Abstract: The SO.sub.2 content of gases is catalytically reacted to form SO.sub.3. The SO.sub.3 -containing gases are cooled in a plurality of stages with a cooling fluid (A) before the SO.sub.3 is absorbed. The absorbing acid is cooled by a cooling fluid (B) which delivers heat to a consumer. To increase the temperature of the cooling fluid (B) or to reduce the expenditue and to prevent a temperature drop in the SO.sub.3 -containing gases below the dew point temperature, the SO.sub.3 -containing gases are cooled first by and indirect heat exchange and then by a second indirect heat exchange with a cooling fluid (A) to a temperature slightly above the dew point temperature of the SO.sub.3 -containing gases. The cooling fluid (A) is conducted in a closed cycle. The sulfuric acid circulated through the absorber is cooled by an indirect heat exchange with a liquid cooling fluid (B), which is conducted in a closed cycle.