Sulfuric acid leaching of ocean manganese nodules using aromatic amines as reducing agents

Sulfuric acid leaching of ocean manganese nodules was carried out using aromatic amines as reducing agents. Seven aromatic amines were tested and they were: aniline, o-phenylene diamine, o-aminobenzoic acid, o-nitroaniline, p-amino toluene, p-aminobenzene sulfonic acid and l-naphthylamine. At ambient temperature and pressure, these aromatic amines markedly increased metal extraction from the nodules. Generally, extraction of Mn, Ni and Co increased with increasing reductant dosages. However, for most of the tested aromatic amines, high reagent dosages resulted in rapid decrease in copper extraction, with the exception of p-aminobenzene sulfonic acid. The p-aminobenzene sulfonic acid was found to be the most effective reducing agent for the extraction of Mn, Ni, Cu and Co from the manganese nodules.