Metallgesellschaft Aktiengesellschaft

Uraphos Chemie Gmbh

Manfred Beckmann

Ulrich Heinrich Sander

Karl-Heinz Dorr

Klaus Kobele

Heinz Dittmar

Friedrich Berger

Ernst Rode

Ulrich Rothe

Gerhard Gotz

Walter Bauer

Horst Hartmann

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.

Process of treating aluminum-containing fused slag

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. The temperature of the mixture of feed solution and recycled potassium chloride is maintained only slightly below the temperature of the feed solution, potassium chloride product is withdrawn at the desired rate from one or more of the stages which contain solution at a higher temperature, the vapors formed are withdrawn and are condensed by a direct or indirect cooling.

Process of producing coarse, pure potassium chloride crystals

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. The liquid cooling fluid (B) which has been heated is heated further by an indirect heat exchange with the heated cooling fluid (A). The hot cooling fluid (B) is cooled by an indirect heat exchange with the consumer.

Process of producing sulfuric acid

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Neu-Isenburg, Germany

Manfred Beckmann