A Hybrid Process for Recovering Copper from Dilute Solutions

Abstract

The present paper describes a hybrid process comprising of reverse osmosis (RO) and solvent extraction (SX) techniques for recovering copper from dilute solutions. The solution containing copper is processed through RO to obtain two separate streams, 1. a concentrate stream containing higher concentration of copper and 2. the permeate stream [treated water] suitable for safe discharge. The concentrated solution from RO is further concentrated through solvent extraction/stripping to recover copper. Using the RO technique the copper ion concentration was enriched up to 10.16 kg/m3 from an initial copper concentration of 100 g/m3. The metal ion concentration in permeate stream increased from 0.76 g/m3 to 362 g/m3 with increase of feed concentration from 100 g/m3 to 6.0 kg/m3. The permeate stream was recycled through RO to obtain a treated water containing metal ion within tolerance limit for re‐use. The concentrated solution containing copper was further processed employing solvent extraction technique using LIX 84I(as the extractant). The extraction efficiency ranged between 84.27 and 92.08% at the A:O ratio of 1:1, 1:1.5 and 1:2. The percentage extraction (in a single stage) increased from 74.26 to 84.27% with increase of LIX 84I concentration from 30 to 50 vol.%. The loaded organic generated under the above optimum conditions was used in stripping studies. The stripping efficiency (in a single stage) increased from 83.30 to 99.50% with increase of H2SO4 concentration from 100 to 150 kg/m3.