SORPTION OF RHENIUM FROM SULFURIC ACID SOLUTIONS BY IMPREGNATES CONTAINING TRIALKYLAMINES

Abstract

The paper studies rhenium (VII) sorption from sulfuric acid solutions by impregnates based on macroporous polymer carriers (copolymers of styrene with divinylbenzene, weak acid cation exchange resion) containing commercial trialkylamine (ТAA). The study provides equilibrium and kinetic characteristics of rhenium recovery by the impregnate based on the macroporous weakly acidic cation exchange resin (K-TAA) having the best rhenium capacity. The maximum coefficient of rhenium distribution in the K-TAA impregnate is observed in sorption from pH = 2 solutions. The rhenium sorption isotherm is described by the Langmuir equation with the K = 29±2 ml/g constant. A limited solution volume method was used to obtain the integral kinetic curves of sorption with a half-reaction time value considered to calculate the effective coefficients of rhenium diffusion in the impregnate amounted to (3,8·10–11 (295 K) and 1,3·10–10 (308 K) m2/s). Kinetic results linearized by the equations of models (pseudo-first, pseudo-second order, Elovich and inner diffusion) showed that kinetic curves with the highest correlation degree are described by the pseudo-second order equation with the 0,00056 (295 K) and 0,00059 (308 K) g·mg–1·min–1 rate constants. The apparent activation energy of rhenium sorption (39±2 kJ/mol) was calculated using the Arrhenius equation. The K-TAA impregnate was tested for rhenium sorption from the eluate obtained by rhenium desorption from the Purolite A170, weak base anion exchange resin pre-saturated with rhenium from the complex pregnant solution for leaching of products derived from poor rhenium-containing copper sulfide raw materials processed.