Nearly all cobalt is found associated with ores of copper, nickel, or copper-nickel.
In the copper-cobalt ore bodies of central Africa and Russia, cobalt occurs as sulfides (carrollite, linnaeite, or siegenite), the oxide minerals heterogenite (hydrated cobalt oxide) and asbolite (a mixture of manganese and cobalt oxides), and the carbonate sphaerocobaltite. In the copper-nickel-iron sulfide mines of Canada, Australia, Russia, and other regions, cobalt is present in place of nickel in many minerals.
Cobalt arsenides, such as smaltite, safflorite, and skutterudite, with the sulfoarsenide cobaltite and the arsenate erythrite, are mined in Morocco and on a much smaller scale in many other countries. These are the only primary cobalt ores.
Huge nickel-containing deposits found in New Caledonia, Cuba, Celebes (Indonesia), and other regions contain a small quantity of cobalt in the form of oxide minerals, such as asbolite.
A few pyrite (iron disulfide) deposits mined for their sulfur content contain enough cobalt to warrant the extraction of the latter from the roasted residue. Cobalt sulfides occasionally occur in lead-zinc deposits in quantities sufficient to justify their recovery.
These deposits are primarily worked for copper with cobalt as a by-product. They account for over 50% of world cobalt mined production. Major deposits are characterized by ore minerals contained within organic-rich pyritic shales and sandstones deposited in a near-shore lagoonal environment, under reducing conditions. These mineralized sediments are always found above oxidized terrestrial clastic sediments.
Two of the largest and most well-known deposits of this type are the European Kupferschiefer and the Central African Copperbelt.
Hydrothermal and Volcanogenic
This deposit type groups together a wide range of deposit styles and mineral assemblages. The key process is precipitation from hydrothermal fluids passing through the host rock often sourced from, or powered by, volcanic activity. Ores can be found where minerals have been remobilized along fault planes, in veins, fissures, and cracks, or as metasomatic replacement of host rocks.
If a mafic to ultramafic melt becomes saturated in sulfur (generally because of contamination from crustal-derived sulfur), an immiscible liquid sulfide phase will form, into which nickel, cobalt, and platinum-group elements (PGE) preferentially partition. These elements are thus scavenged from the residual magma and are deposited in discrete sulfide-rich layers.
The largest and most economically important magmatic sulfide deposits include:
Norilsk, Russia Merensky Reef, South Africa Kambalda, Western Australia Sudbury, Canada
In tropical and subtropical climates intense weathering of ultramafic rocks may cause significant cobalt and nickel enrichment in surficial residual deposits known as laterites. Cobalt dispersed in silicates and sulfides within the host rock is remobilized and deposited in weathered layers as hydroxides and oxides near the surface and as silicate at deeper levels. These deposits are generally about 20 meters thick and mid-Tertiary to recent in age. They are principally worked for nickel with cobalt as a by-product. The cobalt is contained within limonite and goethite as well as erythrite and asbolite. At deeper levels, weathering of ultramafic rocks is less intense and the nickeliferous mineral garnierite is formed.
Cobalt ore processing
The most important sulfide sources, the copper-cobalt ores of Congo (Kinshasa) and Zambia, are processed in a conventional manner to produce a copper-cobalt concentrate. This is then treated by flotation to separate a cobalt-rich concentrate for treatment in the cobalt circuit. Separation flotation utilizes pneumatic and mechanical agitation to produce air bubbles that carry the mineral particles to the surface. Different reagents are used to attract the cobalt minerals to the bubbles in preference to copper. Cobalt concentrates, which can contain as much as 15 percent cobalt, are then processed further, using either pyrometallurgical or hydrometallurgical extractive processes.
Here we Pineer Mining Machinery, could supply customers with full project solutions for cobalt ore mining/processing.
Welcome to contact us for more details.