Processing of Deep-sea Nodules by Silicothermic Reduction

Abstract

Deep-sea nodules are ores formed on the sea floor at depths of 3000 to 6000 m as a result of sedimentation. They range in size from 1 cm to 15 cm and contain mainly manganese and iron and other elements that are collected from the nodules by complex pyrometallurgical and hydrometallurgical processes. These other elements of interest are bound in the nodules mainly in the form of manganese and iron oxides. In order to achieve a high yield of metals bound in nodules in the form of oxides, it is necessary to disintegrate this arrangement in the lattice. This can be achieved by exposing the deep-sea nodules to a reducing condition. This paper deals with the one-step recovery of metals of interest from nodules using silicothermic reduction with 10% excess silicon over stoichiometry. The phase composition, microstructure and mechanical properties of the obtained reduced material were determined.