The solvent extraction of arsenic from spent copper electrolyte by tri-n-butyl phosphate (TBP) was studied in order to develop a new process for purification of spent copper electrolyte. The paper includes selection of a favorable extractant, the results of batch-wise, step-wise and continuous counter-current extraction tests to determine the optimum conditions. The optimum conditions for spent copper electrolyte are the extraction with undiluted TBP at O/A=2 and the stripping with water at O/A=5 at55°C, whereas thos6 for mother liquor from copper sulfate plants are nearly the same but O/A for the stripping should be less than 3. Under these conditions, more than 85% of arsenic can be successfully removed from both spent copper electrolyte and mother liquor.
