Preliminary Study of Synergistic Extraction Iron from Acid Leaching Solution of Cyanidation Tailings with P204 and 2-octanol

The system of P204-2-octanol was used to extract Fe(Ⅲ) from the acid leaching solution of cyanidation tailings of gold concentrates.A preliminary study was made on the extraction mechanism.Investigations were carried out on the effects of the extraction system,P204 concentration,initial pH value of feed liquid,iron content and medium NaCl on Fe extraction rate as well as the effects of phase ratio(O/A) and H2SO4 concentration on Fe(Ⅲ) stripping.It was found that P204 and 2-octanol have a certain synergistic extraction effect on extracting Fe(Ⅲ) from the acid leaching solution.As phase transfer reagent in the extraction system,2-octanol could particularly improve the stripping efficiency.The extraction rate of iron could be greatly improved after the saponification of the extraction system with ammonia.Using the extraction system containing P204,2-octanol and 260# solvent oil with a volume ratio of 1∶1∶2,and adjusting pH value of the original acid leaching solution with 10.18 g/L iron content to 2.0 at the O/A ratio of 2,after one-stage extraction,Fe3+ concentration in raffinate was less than 0.25 g/L.Fe3+ in the organic phase was mostly stripped using 25%(volume fraction) sulfuric acid.The contents of impurities,especially arsenic,in the solution were greatly reduced through the methods of extraction and stripping.