Resin-in-pulp

Resin additives Resin cements Resin component Resin cure systems Resin curing agents Resin formation Resin-in-pulp Resinoid Resinols Resins... 

Uranium ores are leached with dilute sulfuric acid or an alkaline carbonate [3812-32-6] solution. Hexavalent uranium forms anionic complexes, such as uranyl sulfate [56959-61-6], U02(S0 3, which are more selectively adsorbed by strong base anion exchangers than are other anions in the leach Hquors. Sulfate complexes are eluted with an acidified NaCl or ammonium nitrate [6484-52-2], NH NO, solution. Carbonate complexes are eluted with a neutral brine solution. Uranium is precipitated from the eluent and shipped to other locations for enrichment. Columnar recovery systems were popular in South Africa and Canada. Continuous resin-in-pulp (RIP) systems gained popularity in the United States since they eliminated a difficult and cosdy ore particle/leach hquor separation step. 

RIP [Resin in pulp] A general term for hydrometalluigical processes in which an ion-exchange resin is mixed with a suspension of a ground ore in water. The desired metal is selectively extracted into the resin. See CIP (1). 

T0465 Klohn-Crippen Consultants, Ltd., ChemTech Soil Treatment Process T0469 Kvaemer Metals, Resin-in-Pulp/Carbon-in-Pulp... 

T0469 Kvaerner Metals, Resin-in-Pulp/Carbon-in-Pulp... 

The Resin-in-Pulp (RIP) and Carbon-in-Pulp (CIP) processes were developed for the ex situ treatment of soils, sediments, dredgings, and soUd residues that are contaminated with organic... 

The eluant is usually 1 M N07 in the form of NH4NO3. The physical method for carrying out the extraction can involve (a) a fixed resin bed, (b) a resin-in-pulp technique where resin in baskets is passed through a stream of pulp or slurry from the leach process, or (c) a moving bed of resin. 

Fig. 21.12. Uranium ore mill processes (A) carbonate leach, caustic precipitation process (B) acid leach, ion exchange and acid leach, solvent extraction processes (C) acid leach, resin-in-pulp process.

The resin beads used in most columnar operations range in size from 0.3 to 0.9 mm in diameter, which is a compromise based on the effect of ion-exchange rates, capacities, and hydraulic characteristics. The especially made resins used in resin-in-pulp operations range in size from 0.8 to 1.6 mm in diameter. The apparent density of a resin is defined as that weight of backwashed and settled wet resin per cubic foot, which for resins used in the uranium industry is about 38-45 Ib/ft . In column operations, the attrition losses due to swelling and contraction of resin, abrasion of resin-resin surfaces, and abrasion of resin-equipment surfaces are negligible. In resin-in-pulp operations, an appreciable amount of attrition loss is encountered. 

Carman (C6) described the successful development and application to a uranium resin-in-pulp process of a continuous countercurrent ion-exchange pilot plant. This new technique is based on the observation that the resins at the correct level of air agitation float in close proximity to the surface of the pulp. So long as the resin beads are able to move about gently but freely in the surface layer, a satisfactory rate of ion exchange is possible. Under this condition, the mechanical damage to the resin due to attrition is negligible. 

Smaller continuous fluid bed systems, like the one shown inFig. 38,1 have been developed which operate with a high concentration of ion exchange resin and suspended solids. These units are 80% smaller than the conventional resin-in-pulp plants of the type which are used in the treatment of uranium ore slurries. 1 The pilot plant unit, which would probably be the size needed for processing commercial fermentation broths, had dimensions per contact chamber of 0.82 m x 0.82 mwithafluid bed height of 0.82 mand an additional 0.16 m for free board. The unit has been successfully operated with 25 to 50% resin and up to 45% suspended solids. 

Resins are used in the form of small spherical beads. For fixed-bed operation on clear solutions, the standard particle size range is —16 to -1-50 mesh (1.0 to 0.6 mm). For operation on unclarified solutions, in the resin-in-pulp type of operation to be described later, larger particles in the size range —14 to 4-20 mesh (1.1 to 0.9 mm) are preferred. 

Ion-exchange equipment. Three types of ion-exchange equipment used in U.S. uranium mills are the fixed-bed type, the moving-bed type, and the continuous resin-in-pulp (RDP) type. These will be described in turn. 

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