process for the concentration of uranium in the slag, phosphorus furnace, for the subsequent extraction of uranium

摘要

Uranium values are recovered from slags derived from the reduction of phosphates in the presence of silica, by subjecting to acid attack so that the calcareous constituents are dissolved, leaving the uranium in the solid residue from which it can be extracted. The slag is ground so that all of it can pass through a Tyler 150 mesh screen and is diluted with an approximately equal weight of water. Acid is added to the agitated pulp, local concentrations of acid being avoided by successive small additions or slow continuous addition. The acid may be hydrochloric, nitric, perchloric or phosphoric. The uranium content in the solid residue may be recovered by conventional attack with sulphuric acid or sodium carbonate, or it may be re-used as part the charge to the phosphorus reduction furnace so as to enrich the silica slag with respect to uranium.ALSO:A process for the recovery of uranium wherein slags derived from the reduction of phosphates in the presence of silica are subjected to a mode of acid attack such that the calcareous constituents are dissolved while leaving the uranium in a solid residue from which the uranium can be extracted. The slag is ground so that all of it can pass through a Tyler 150 mesh screen and is diluted with an approximately equal weight of water. Acid is added to the agitated pulp, local concentrations of acid being avoided by successive small additions or slow continuous addition. The acid may be hydrochloric, nitric, perchloric or phosphoric, the latter being included at the rate of 5-15 litres per ton of slag if another acid is used when a low content of P2O5 in the slag could cause serious risk of the calcium salt produced being discoloured by ferric ions. The strength of the acid used is 5-6 N and the attack lasts at least one hour, the temperature being maintained at 70-80 DEG C., and the final pH of the pulp being 2-3. The precipitate from the reaction is washed in counter-current using 6-8 cubic meters of water per ton of slag. The uranium content in the solid residue may be recovered by conventional attack with sulphuric acid or sodium carbonate, or it may be re-used as part the charge to the phosphorus reduction furnace so as to enrich the silica slag with respect to uranium. p