Saint-Petersburg State Institute of Technology, Saint Petersburg, Russia:

S. A. Egorov, Postgraduate Student at the Department of Rare Elements and Nanomaterials Engineering, e-mail: egorovserg-92@yandex.ru
A. A. Blokhin, Professor at the Department of Rare Elements and Nanomaterials Engineering, Doctor of Technical Sciences, e-mail: blokhin@list.ru
Yu. V. Murashkin, Associate Professor at the Department of Rare Elements and Nanomaterials Engineering, Candidate of Chemical Sciences, e-mail: murashkin-1@mail.ru

VNIIKhT JSC, Moscow, Russia:
A. V. Tatarnikov, Lead Researcher, e-mail: avtatarnikov@yandex.ru

It was established that ading of rhodium-containing solutions at higher temperature (~80 ^oC) significantly increases the ligand exchange reaction rate in rhodium (III) chloride solutions and forces most of the contained rhodium to transfer to a kinetically labile hexachloride complex. The authors analysed the rhodium sorption on the strong base anion exchange resin Purolite A500, the weak base anion exchange resin Purolite A111 with tertiary functional groups, the weak base anion exchange resins Purolite S984 and Purolite S985 with polyethylene polyamine functional groups, the complexing ion exchange resins Purolite S914 and Purolite S920 with thiourea and isothiourea functional groups from HCl solutions with various concentrations in the presence of, g/l: 6.0 Fe (III); 4.2 Al (III); 5.2 Zn (II); 4.1 Sn (IV) and 2.0 Ce (III), after they had been subjected to thermal treatment and when no prior thermal treatment had taken place. It is shown that during sorption from pre-soaked (at ~80 ^oC) solutions the rhodium distribution ratios are ~1.5 times higher than during sorption from solutions soaked at room temperature, while the highest selectivity to rhodium is demonstrated by S984 and S985 resins. These are followed by the S920 and S914 resins. When using A500 and A111 resins, the rhodium distribution ratios are much lower. It was found that the prior thermal treatment of the 4 mol/L multicomponent HCl solutions raises the rhodium capacity of the S984 and S985 resins by 5–9 times and that of the S914 and S920 resins by 3–7 times depending on the steady-state concentration of rhodium. It is demonstrated that sorption of rhodium on the S984 resin in dynamic conditions from a multicomponent chloride solution activated at high temperature is associated with a significantly higher recovery rate that sorption of rhodium from a solution that was not thermally pre-treated.

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