RECOVERY OF URANIUM VALUES FROM URANIUM BEARING MATERIAL

摘要

A process for recovering uranium values from uranium bearing material also containing iron and arsenic and/or claylike minerals includes leaching the uranium-bearing material in aqueous sulphuric acid solution under oxidizing conditions to provide a slurry comprising undissolved residue and an acidic sulphate solution containing dissolved uranium values, with the residue containing clay-like minerals and/or the solution containing ferric and arsenate ions. A sequence of settling operations in a series of settling vessels is carried out to effect countercurrent washing of the residue. The settling operations include feeding the slurry to a first settling vessel together with solution from the upper portion of a second settling vessel, removing leach solution containing uranium values from an upper portion of the first settling vessel after settling has occurred, subsequently feeding the residue from the first settling vessel to each successive separating vessel in turn and supplying solution to each settling vessel from an upper portion of a subsequent settling vessel and allowing the residue to settle in the solution, and supplying the last settling vessel in the series with water from a source thereof. The sulphuric acid concentration of the solution in each settling vessel in at least the first half of the series is maintained at at least about 5 g/L by adding sulphuric acid to at least one of the settling vessels in the final part of the series.