Treatment of Chloride Waste Pickle Liquor by Solvent Extraction for the Recovery of Iron

Abstract

A systematic study of the extraction of Fe(III) from chloride waste pickle liquor has been investigated using Cyanex 923 diluted with kerosene to recover iron values from the pickle liquor. Various parameters were studied to optimize the conditions for maximum recovery of iron. Extraction increases with increasing concentration of both hydrochloric acid and extractant. The species extracted into the organic phase appears to be HFeCl₂ with 1 M of the solvent. Effect of various salts as additives on Fe extraction was also studied and it was found that addition of NaCl enhanced the extraction about 2.5 times as compared to that without its addition.

Saturated loading capacity was found to be 60.9 g/L Fe in four contacts at O/A of 1. The stripping of Fe(III) with different concentration of hydrochloric acid and nitric acid from the loaded Cyanex 923 was found to increase up to 1 M of both the acids and then decrease with further increase in acid concentration up to 10 M. However, 100% stripping efficiency of Fe(III) was achieved with 0.8 M oxalic acid in two countercurrent stages at an aqueous:organic phase ratio of 3:1. Extraction parameters for maximum extraction of Fe(III) were optimized.

Keywords:

• chloride waste pickle liquor
• cyanex 923
• iron recovery
• solvent extraction
• TRPO

ACKNOWLEDGMENTS

The financial support for the work by the Department of Science and Technology (DST) under ILTP program, New Delhi, India is gratefully acknowledged. The authors are thankful to the Director, National Metallurgical Laboratory, Jamshedpur for his kind permission to publish this work.