Article révisé par les pairs
| Résumé : | Formaldehyde oxime, CH2=NOH, has for a long time been recognized as a sensitive colorimetric reagent for manganese, copper and metals of the iron group. In alkaline medium, the oxime dissociates, forming the CH 2=NO- anion which bonds to multivalent metals, giving complexes of the general formula M(CH2NO)6(6-n)-, where n is the oxidation state of the metal1,2. Here I report the results of experiments which show that aqueous formaldehyde oxime constitutes a new and effective leaching agent for several types of ores, such as pyrolusite, malachite, heterogenite and deep-sea manganese nodules. The reagent seems particularly attractive for nodules, as the leaching is rapid, in acid as well as in neutral and or alkaline media, and at ambient and lower temperatures. Manganese nodules constitute an important potential source of nickel and especially cobalt: The amount of cobalt recoverable from the north-west equatorial Pacific alone is estimated5 to be 4×106 tonne - Of the same order as the world total land-based reserves. © 1986 Nature Publishing Group. |
