Abstract

A green and effective process for bromine recovery from crude bromine salts by-products (CBSBPs) of waste printed circuit boards smelting was developed. Over 99 % of bromine was first converted to Br2(l) under optimal acid oxidation conditions (pH 0, NaClO3 10 g/L, stirring rate 200 rpm, time 30 min). 98.25 % of the as-formed Br2(l) can be then purified and recovered by precisely controlling the extraction (single extraction O/A 1.5, multiple extraction O/A 1/3, extract stages 4, extraction time 3 min, and vibration time 2 min) and stripping (Na2CO3 20.5 g/L, CO(NH2)2 3.15 g/L, stripping A/O 1/3, stripping time 3 min, stripping temperature 55 °C) conditions. The purity of the recovered NaBr exceeds 99 %. Moreover, zero wastewater discharge and the remaining stripping organic phase can be repeatable used over 15 times. The proposed method is a sustainable, green, and closed-loop process for bromine recovery from CBSBPs.