Abstract
In the present paper, solvent extraction process has been used for extraction of cadmium from sulfate solution using di-(2-ethylhexyl) phosphoric acid (D2EHPA) with 1% isodecanol in kerosene diluent expected from industrial effluents or leaching of ores/secondary materials. Different process parameters such as pH, contact time, extractant concentration, O/A ratio etc. were investigated. Results demonstrated that quantitative extraction of cadmium was feasible from 4.45 mM cadmium feed solution in single stage at equilibrium pH 4.5, time 2 min and O/A ratio 1:1 with 0.15 mM D2EHPA. The extraction mechanism of cadmium from sulfate solution by D2EHPA in kerosene could be represented at equilibrium by Cd
2
+
+
3/2 (H
2A
2)
org
⇔
CdA
2(HA)
org
+
2H
+. The loading capacity of 0.15 mM D2EHPA in sulfate solution was determined to be ∼
8.9 mM cadmium. The loaded cadmium was effectively stripped using 180 g/L sulfuric acid. The metal or salt could be produced by electrolysis or crystallization from the stripped solution.
