Technological problems concerning the complex recovery of uranium and accompanying elements from sedimentary ores

In Poland a deposit of carbonaceous clay shales has been discovered, it contains 1600ppmV, 100ppmu and 180ppm Mo. On the basis of the experiments carried out on the laboratory scale, it has been shown, that the leaching of the shales by means of the diluted solutions of sulphuric acid or sodium carbonates does not assure the high recovery of vanadium and uranium because of their occurrence in shales in refractory forms. The treatment of the shales by using of the concentrated sulphuric acid /250g/1kg shales/, according to the ''acid cure'' method and baking them in the temperature of 2500C, has permitted the recovery of 70% vanadium and 65% uranium. From the acid leaching residue, or from the shales directly, 70% of molybdenum can be gained, employing an alkaline pretreatment. The solutions after acid leaching contain great quantities of Al and Fe, which before the separation of U and V by solvent extraction must be to some extent removed. The performed tests have confirmed this, and by using a crystallization process, as by-products the aluminum- and iron sulphates have been obtained. From the solutions, after crystallization by amine solvent extraction, the uranium and vanadium concentrates have been recovered. The currently recognized technological method has been estimated as difficult and expensive. In order to utilize, more economically, this low grade and very refractory for pretreatment shales it is necessary to continue intensive technological research on the improvement of the recognized method and explore new ways, which could contribute to successful solution of this complicated technological problem