Sorption Recovery of Platinum Metals from Production Solutions of Sulfate-Chloride Leaching of Chromite Wastes

This paper discusses the scientific rationale for methods of platinum metals sorption centralization from saturated solutions with a high content of macrocomponents. Methods of sorption centralization of platinum and iridium using local anionites such as AH-31, AB-17-8, Purolite S985 are described. The sorbents used were conditioned to remove organic and mineral impurities. The sorption isotherms of platinum group metals 1/EC=f(1/Cp) at a temperature of 20 °C and a duration of 24 h were plotted. The data on the sorption recovery of platinum and iridium from individual and combined sulfate-chloride solutions were determined. Isotherms of iridium sorption from sulfate-chloride solution are formed. Results of the apparent sorption equilibrium constant and values of standard Gibbs energy (ΔG, kJ/mol) of ion exchange for sorption of platinum and iridium from individual and combined sulfate-chloride solutions are presented. Linearized isotherms and kinetic curves of joint sorption of platinum and iridium from sulfate-chloride solution are described. Comparative sorption of the platinum-group metals (PGM) by anionites AB-17-8 and Purolite S985 from sulfate-chloride solutions is shown. The sorption diagram of platinum and iridium from sulfate-chloride product solutions is presented. It has been revealed that complete recovery is achieved using chelation ion-exchange resin Purolite S985, with recovery of Pt up to 95% and Ir more than 73%. The sorption process is accompanied by intradiffusion constraints that are confirmed by the analysis of kinetic curves using Schmukler and Boyd–Adams models.

Technological Capabilities of Hydrocarbonyl Processes in the Concentration and Separation of Platinum Metals

The principal possibility of processing the industrial poor collective concentrates of platinum metals using a hydrocarbonyl technology with the selective concentration of platinum metals from poor multicomponent chloride and chloride-sulphate solutions with the subsequent production of pure platinoids is shown.

SORPTION EXTRACTION OF PLATINUM METALS FROM CHLORIDE – SULFATE AND SULFATE ACIDIC SOLUTIONS BY POLYACRYLONITRILE FIBERS FIBAN

The sorption of platinum group metals by fibers FIBAN AK-22 and A-5 from acidic chloride-sulfate and sulfate solutions was studied under static conditions. FIBAN contains primary, secondary and tertiary amino groups. The degree of extraction of platinum metals is calculated. The optimal conditions of sorption from the model solutions are determined. The influence of the temperature regime on the sorption process is established. It is shown, that all platinum group metals are quantitatively extracted from acidic chloride-sulfate solutions by fiber FIBAN AK-22 regardless of the concentration of chloride ions, H2SO4 and temperature absorption. Extraction exceeds 96% at a concentration of sulfuric acid up to 3 mol/dm3 and chloride ion up to 1 mol/dm3. Extraction of osmium is maximum at a concentration of sulfuric acid and chloride ion 3 mol/dm3. The degree of extraction of platinum group metals on FIBAN A-5 is from 50 to 85% and is maximum at elevated temperature and concentrations of H2SO4 and chloride ion 1 mol/dm3 and decreases with increasing concentration of sulfuric acid. Electronic spectra of platinum metal solutions were obtained and the state of platinum metals in chloride and chloride-sulfate solutions was estimated. After the introduction of sulfuric acid into the system, changes in the electronic spectra of platinum (IV), ruthenium and osmium solutions were noted. The spectra of palladium, rhodium and iridium solutions have not changed. When extracting platinum metals from production sulfate solutions of complex composition with a high content of macro components (Ni, Cu, Fe, Te and Se), the efficiency of fiber AK-22 is shown. The advantages of fiber FIBAN AK-22 over FIBAN A-5 are noted.