Leaching slurry

Fig. 1. Schematic flowsheet of uranium processing (acid leach and ion exchange) operation. Numbers refer to the numbers that appear in the boxes on the flowsheet. Operations (3), (6), (9), and (11) may be done by thickening or filtration. Most often, thickeners are used, followed by filters. The pH of the leach slurry <4) is elevated to reduce its corrosive effect and to improve the ion-exchange operation on the uranium liquor subsequently separated, In tile ion exchange operation (7), resin contained in closed columns is alternately loaded with uranium and then eluted. The resin adsorbs the complex anions, such as UC fSO 4-. in which the uranium is present in the leach solution. Ammonium nitrate is nsed for elution, obtained by recycling the uranium filtrate liquor after pH adjustment. Iron adsoibed with the uranium is eluted with it. Iron separation operation (8) is needed inasmuch as the iron hydroxide slurry is heavily contaminated with calcium sulfate and coprecipitated uranium salts. Therefore, the slurry is recycled to the watering stage (3). Washed solids from 1,6). the waste barren liquor from (7), and the uranium filtrate from (11) are combined. The pH is elevated to 7.5 by adding lime slurry before the mixture is pumped to the tailings disposal area. (Rio Algom Mines Limited, Toronto)...

The effect of the degree of regeneration of the resin on the degree of extraction of a solute was measured by Slater using a seven stage unit. The results are shown in Fig. 39 for the extraction of uranium using a fluidized bed slurry of a strong base resin in a 10% uranium ore leach slurry. 

Sample Preparation (Treatment) No treatment, extraction, leaching, slurry preparation, decomposition, wet (acid/alkaline) digestion, dry ashing, fusion, combustion (bomb/tube), ignition, pyrolysis, avoidance of losses and contamination, complete decomposition/dissolution, dilution scheme... 

Grinstead, R. R. et al. Solvent extraction of uranium from add leach slurries and solutions. Proc. Is/ Int. Conf. on the Peaceful Uses of Atomic Energy, Geneva, 1955, Paper 523. 

The combined leach slurry passes to induced jarosite precipitation (IJP) and primary neutralization (PN). Recycle streams from downstream processes are leached initially, further decreasing free acid and allowing more jarosite formation to occur. Limestone is then added to decrease iron levels further and neutralize free acid. 

Of the purely atmospheric leach options presented, sequential limonite - saprolite atmospheric leaching gives the best extractions for a given total acid addition and generally produces a leach slurry ready for further (induced) jarosite precipitation with a minimum of limestone addition. 

P.B. Queneau, et al.. Control of Silica Deposition During Pressure Let-Down of Acidic Leach Slurries, Hydrometallurgy - Research, Development and Plant Practice, K. Osseo-Asare, J.D. Miller Eds., 112 AIME Annual Meeting, Atlanta, Georgia, USA, 1983, 121-137. 

The recovery of nickel and cobalt from the leach slurry arising from the saprolite or Caron tails leach can be accomplished by a number of different routes. 

The leach slurry is usually cycloned to separate metalUc lead granules, which are entrained in the slag during separation from the surface of the molten lead in the refining kettle. 

Acidic substrates, examples include copper, nickel and zinc leach slurries, are often best treated using non-ionic or low anionic (<15mol%) copolymers, as the higher anionic ratio polymers tend to precipitate in acidic conditions. 

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