Value Addition to Sulfate Waste Pickle Liquor of Steel Industry Using Hydrometallurgical Processes

Abstract

The solvent extraction of concentrated acid was investigated from sulfate waste pickle liquors using Cyanex 923 (trialkylphosphine oxide (TRPO); manufactured by Cytec Industries Inc., Woodland Park, NJ; provided by Cyanamid Canada Inc. (Markham, Canada)) as an extractant. The effect of various parameters was studied such as extractant concentration, organic-to-aqueous phase ratio, temperature. and retention time on acid extraction from the waste pickle liquor to the organic phase, After the saturation of the organic phase with sulfuric acid, stripping studies were performed to back-extract the pure acid into the aqueous phase. The raffinate of the solvent extraction process that contains both ferrous and ferric iron as well as trace impurities was subjected to oxidation and hydrothermal treatment to precipitate iron with a well-defined pseudo-cubic morphology and a high coercivity value that renders it suitable for high-grade ferrite production.