Uhde Gmbh

Egbert Hoffmann

Friedrich Wolstein

Wilhelm Wengeler

Wolfgang Epper

A process is disclosed separating solids from phosphoric acid produced by the wet process. This is accomplished by relatively simple means but with a high degree of efficiency with reference to the P.sub.2 O.sub.5 content of the phosphoric acid product.

Process for the separation of solids from phosphoric acid

The method for the treatment of phosphate rock that has a content of magnesium compounds in excess of 0.3%. The crushed and screened phosphate rock is mixed with water in a ratio of 1:5 by weight. The mixture is acidified with sulphuric acid, and the reaction mixture is filtered and washed before the neutralization point is reached.

Method for the treatment of phosphate rock

Freshly mined phosphate rock is subjected to screen classification in at least two stages. Only coarse grained phosphate rock with a grain size over 2 mm from the last screen classification step is fed to a plain-roller grinding mill. The rollers of the grinding mill run at different peripheral speeds, so that the grains are ground by radial and tangential forces. This produces a fine grained phosphate rock whose natural moisture content is advantageous when further processed to phosphoric acid by means of sulphuric acid.

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Bochum, Germany

Egbert Hoffmann