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Pachuca tanks are widely used in the uranium industry for ore redistribution [1, 2]. Just as for all mixing apparatus, they are inefficient. Continuous extraction of uranium from ore pulp, sorption extraction from the liquid phase of the pulp, and washing of sorbents requires at least 4-10 Pachuca tanks.We have developed a highly efficient technology for sorption extraction of uranium from ore pulps, washing sorbent from pulp and the regenerating solution [3], as well as sorbent regeneration in the counterflow regime in displacement apparatus -pulsatioual columns. A series of physical-chemical investigations of these processes,' which are necessary for calculating pulsational equipment, was carried out. First, the equilibrium and kinetic characteristics of the processes were measured, and the density of the reagents, rate of settling of the sorbent and sand fraction in the systems investigated, separation of the pulp and others were determined. The hydrodynamics of the sorption processes, performed in the pulp-sorbent system, depends on the aggregate stability of the dispersion systems. A disruption of this stability can result either in the formation of macrophases, which will give rise to intense separation of the system, or development of the spatial network-structure, i.e., transition of a freely dispersed system into a coupled dispersed system, in which the coupling forces between the particles are strong enough to withstand the thermal motion and external actions, and this will increase sharply the viscosity of the system. Therefore, investigation of the laws of structure formation in dispersed systems and investigation of the mechanical properties of structured systems are important in hydrodynamic processes, specifically, accompanying leaching and sorption of uranium from pulps on sorbents. However, these investigations must be conducted directly at the facilities on real media, since the properties of the indicated systems change sharply in time. The rate of settling of a sorbent in pulp indireedy reflects these properties, and for this reason, once it is determined experimentally, k can then be used for calculations of the hydrodynamic regime in a pulsation column in the pulp-sorbent system.In the initial uranium-containing pulp with density 1.32.10 -3 kg/m 3, the anion exchange AMP, whose density is 1.25" 10-3 kg/m 3, becomes distributed uniformly and is suspended in the volume of the pulp as a result of the high viscosity and density. When this pulp is diluted with water to separate the sand fraction of the pulp and the pulp is washed at the same time, the viscosity and density of the pulp drops sharply and the sorbent starts to settle (see Table 1).According to the data presented in Table 1, the acceptable, for performing counterflow sorption of uranium with AMP from pulp, rate of settling of the sorbent is achieved by diluting the initial pulp by a factor of 2. Not only the hydrodynamic regime in the pulsational column but also the dimensions of the column and the amount of pulp necessary for sorpti...

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Results are presented for investigation of the continuous counterflow wash-out of solid phase (precipitate after breakdown of a chemical uranium concentrate) in an experimental-industrial plant with a pulsed column 400 mm in diameter and 8 m high.Rare, trace, and radioactive elements are usually extracted from raw material by the hydrometallurgical method; here, a slurry, whose liquid phase (LP) contains the dissolved element, is obtained [1]. In separating the phases, the dissolved target components should be removed from the solid phase (SP) -insoluble precipitate.The dissolved substance is separated from the moisture of the precipitate (wash-out or flushing) by replacement of the mother liquor with fresh flushing fluid. Usually the SP is the product produced, and the flushing solution the waste product during flushing, while the strengthened solution is the product that product produced, and the SP is the waste product during wash-out [2].During counterflow in the replacement mode, the existence of a difference in the deposition rates of the SP and the ascending flow of flushing fluid exists during counterflow wash-out of the SP of a suspension. After the breakdown of a chemical uranium concentrate by nitric acid, however, the deposition rate of the SP is negligible; preliminary flocculation of the suspension obtained is therefore required for its wash-out in a counterflow replacement regime in a pulsed vessel.The deposition rate of the SP was determined from the accumulation of sediment Q at the bottom of a calibrated cylinder, and rate of clarification (deposition of floccules) v, i.e., the travel speed of the phase interface [1-5].Polyacrylamide (PAA) was used as the flocculating agent, and the deposition rate of the floccules was determined as the PAA was added to the suspension:• v = 0.2 m/h after completion of breakdown of the chemical concentrate (t ≤ 100°C);• v = 0.34 m/h after the slurry had been heated to 90°C, and agitated for 30 min (breakdown when t ≤ 45°C); and• v = 0.28 m/h after breakdown had been completed at t ≤ 45°C, and the slurry heated to t = 90°C and agitated for 30 min. In all cases, the average deposition rate of the flocculated SP was found to be low, and, as a result, wash-out productivity was low in the pulsating column vessels. As practice indicates, the difference between the deposition rare of the SP and the ascending flow of flushing fluid should be 1-4 m/h to ensure counterflow wash-out.Mixing of the slurry produced after breakdown of the chemical concentrate with the reclaimed product of uraniumore sorption reduction increases the deposition rate of the SP to 0.6 m/h. The addition of a flocculent leads to a pronounced increase in the deposition rate of the SP, whereupon it is established that flocculation is improved after dilution, since the floccules that have formed here are partially disintegrated.After treatment with the flocculating agent, the deposition rate of the finely disperse SP was determined as a function of its concentration. It is apparent from Fig. 1 that this...

Both in this country and abroad, zeolites are produced mainly in reactors with a stirrer operating in the discrete regime, or in a cascade of reactors working in the continuous regime [1]. At ion exchange, the number of reactors is n =N/q, where N is the number of theoretical steps of contraction; 1/is the efficiency of apparatus.If the ion exchange is carried out in a column apparatus in the counterflow regime, the process can be conducted in the same equipment [2, 3].Pulsation columns are designed on the basis of calculations using the results of physico-chemical investigations. Equilibrium and kinetic dependences of the exchange of a sodium ion on a magnesium ion on type A zeolite with particles 50-I00/Lm in size were recorded under the static conditions by the method of separate points using the procedure of investigating the processes of sorption of metal ions on synthetic ion-exchange resins. The phases were mixed using a propeller or magnetic stirrer. The rotation speed of the stirrer was selected to ensure efficient mixing of the phases and operation in the mixeddiffusion region. The equilibrium and kinetic dependences of exchange of sodium ions on the magnesium ion in type A zeolite are presented in Figs. 1 and 2. The dependences were used for the graphical determination of the kinetic coefficient of mass exchange B as the tangent of the angle of inclination of the straight line in the coordinates hi((~,e-Ci)-r (here (~e and (~i are the equilibrium and actual concentration in the sorbent phase). The data were processed by the method described in which shows that the kinetic mass exchange coefficient can be determined as the tangent of the angle of inclination of the straight line in the coordinates -ln(Ce-Ci)-7" (Fig. 3). The convex shape of the isotherm of ion exchange of Na + on Mg 2+ indicates a high affinity of the ionogenous group of type A zeolite to the Mg 2+ ion, which is higher than that for the Na + ion. It should be mentioned that the kinetic coefficient of mass exchange B, equal to 32.4 h-I, is an order of magnitude higher than for the ion-exchange resins of the type AMP, SG-1, AN-l, etc., which indicates the high rate of the ion exchange process. After transferring the zeolite into the Mg form it must be rinsed to remove the magnesium chloride solution. The equilibrium and kinetic characteristics of the process of washing zeolite to remove the magnesium chloride solution, obtained using this procedure, show that equilibrium in washing zeolite occurs almost after 1 min and the washing isotherm is straight and is governed by the Donnan distribution of a strong electrolyte between the liqu;,d and solid phases and is described by Henry's equation