STUDIES OF EXTRACTIVE REMOVAL OF SILVER(I) FROM NITRATE SOLUTIONS BY CYANEX 471X

Silver(I) extraction from nitrate solutions by Cyanex 471X (triisobuty lphosphine sulphide) was investigated. The optimal conditions of silve r(I) removal were determined depending on the concentration of purifie d salts, concentration of nitric acid, concentration of Cyanex 471X, k ind of diluent and modifier, as well as phase contact time. Silver(I) extraction isotherms, using 2.5 and 5% Cyanex 471X and D2EHPA or TBP, were determined depending on nitric acid concentration. In the case of a 6 MHNO(3) solution a rapid decomposition of Cyanex 471X was observe d. The removal of Ag(I) from solutions containing Cu(II), Zn(II), Bi(I II) and Fe(III) was studied. It was found that Cyanex 471X could reduc e the silver content in the purified salts to below 10(-5)%.