マンガン・ノジュール亜硫酸浸出液からの沈殿分離法によるCu, NiおよびCoの回収

抄録

A precipitation separation method has been investigated at ambient temperature to recover Cu, Ni and Co from sulfurous acid leach liquor of deep sea manganese nodules.
The Cu, Ni, Co and Mn values are completely leached out of the nodule byusing a slight excess amount of sulfurous acid for reducing MnO₂ in nodules to Mn²⁺, whereas 30% of Fe is undissolved. Fe²⁺ is oxidized by aeration and precipitated as Fe (OH) ₃ by adjusting pH of the leach liquor to 4.2-4.4. Subsequently, Mn is precipitated as MnCO₃ by adding (NH₄) ₂CO₃ when Cu, Ni and Co in the solution are stabilized as ammine-complexes in the presence of NH⁺₄ added as ammonia-water, (NH₄) ₂CO₃, (NH₄) ₂SO₃ or (NH₄) ₂SO₄. After several trials, over 90% recoveries of Cu, Ni and Co are obtained and about 97% of Mn and 99.9% of Fe could be removed. The optimum conditions for recovering metal values will be discussed.