Nickel ores

The basis is the industrial taxonomy of deposits , based on the morphology of ore bodies , the geological conditions of their occurrence, the mineral and material composition of the ores, and the features of their technological processing.

The main types of nickel deposits are as follows:

1. copper- nickel sulfide deposits: Norilskoye (including Talnakhskoye and Oktyabrskoye ), Monchegorskoye (also Nickel ), Kaula and others (CIS), the Sedbury ore district and the Thompson deposit (Canada), Kambalda (Australia);
2. nickel silicate and cobalt- nickel silicate, mainly stratiform deposits of the South Urals and Pobuzhie (including oxide-silicate ferro-nickel), Cuba, Indonesia, New Caledonia , Australia.

Minor types:

1. copper pyrite deposits;
2. vein sulfide-arsenide complex deposits.

A potential source may be ferromanganese nodules of the bottom of the oceans.

1. Type one. Magmatic sulfide copper-nickel deposits . Ore formation - the initial accumulation and separation of sulfides - occurs in the process of introduction, differentiation and segregation of the initially homogeneous nickel-bearing melt into two liquids: silicate and sulfide components. Sulfide melt, due to its greater weight, sinks and concentrates in the bottom parts of intrusions and crystallizes after crystallization of the silicate melt. The rise of nickel-bearing magma occurs along deep faults that penetrate deep into the mantle , which determine the geological position of ore regions and fields of copper-nickel deposits. Deposits of sulfide copper-nickel ores are associated with lapolite-like or plate-like massifs of stratified gabbroids confined to zones of deep faults on ancient shields and platforms .

The form of ore bodies of the largest deposits is stratiform (Frud-Stobi, Thompson, etc. in Canada; Norilsk 1, Talnakhskoye and Oktyabrskoe in the CIS; Flounder in Australia, etc.), often coinciding with the direction of stratification of intrusive massifs. Many deposits (Monchegorskoye, Kaula in the CIS; Lynn Lake in Canada; Pilansberg in South Africa; a number of deposits in Australia) have a veined , column-shaped or more complex form of ore bodies, determined by discontinuous violations.

A characteristic feature of copper-nickel deposits around the world is the aged mineral composition of ores: pyrrhotite , pentlandite , chalcopyrite , magnetite ; In addition to them, pyrite , cubanite , polydimite , nickelin , millerite , violarite , platinum group minerals, occasionally chromite , nickel and cobalt arsenides, galena , sphalerite , bornite , mackinavite , valerite , graphite , and native gold are found in ores.

Ores are complex. They contain (%): Ni 0.6-5, Cu 0.2-6, Co 0.01-0.1, platinum group metals. The ratio of Ni: Cu = 1.5-2.5: 1, but may be different. The ratio of Co: Ni = 1: 20-1: 40. Poor ores (Ni up to 1.5% - mainly disseminated ores) are enriched. Rich ores (Ni more than 1.5%) can be smelted without dressing. Copper , nickel , cobalt , platinum group metals, gold , silver , sulfur , selenium , tellurium are extracted from copper-nickel ores.

2. Type two. Silicate nickel ores of weathering crust . Exogenous deposits of silicate nickel ores are universally associated with one or another type of weathering crust of serpentenites . during weathering, the stage decomposition of minerals takes place, as well as the transfer of mobile elements, using water from the upper parts of the crust to the lower. There, these elements precipitate in the form of secondary minerals.

In deposits of this type, nickel reserves are 3 times greater than its reserves in sulfide ores, and the reserves of some deposits reach 1 million tons or more of nickel. Large reserves of silicate ores are concentrated in New Caledonia, the Philippines, Indonesia, Australia and other countries. The average nickel content in them is 1.1-2%. In addition, ores often contain cobalt.

Allocate:

but. Deposits of areal crust (Kempirsayskoye, Sakharinskoye, Serovskoye deposits).

Deposits of the Kempirsai group represent the remaining residual cover of the weathering crust on dunites , peridotites , pyroxenites and their serpentinized differences. The area of ​​nickel-bearing plots reaches several square kilometers. The contours of ore bodies with a conditioned metal content are determined by the testing and density of the exploration network. The thickness of the ore bodies is 30 m (average 6 m). In the general case, the profile of the nickel-bearing areal crust is divided into zones: ocher , nontronite , alkaline coils , carbonated coils, unchanged parent rocks - coils. Ore is the nontronite zone, the lower part of the ocher zone and the upper part of the zone of alkaline coils. Deposits are mined in an open way. The thickness of the overburden is 0-40 m.

b. Deposits of linear-areal crust (Rogozhinskoye, Cheremshanskoye deposits, Middle Urals).

Industrial nickel ores are represented by ocher, nontronite, nontronized and leached serpentites. According to the material composition and technological properties, two types of ores are distinguished: glandular, with a high content of cobalt; magnesian, with a high content of nickel. The deposits are characterized by two mineralization zones. The upper zone is represented by nickel-bearing laterites and silicification sites with up to 60-70% iron oxide and 1-2% nickel. The lower zone is composed of rich garnierite - serpentite ores, which occur under the areal nickel-bearing weathering crust. Ore bodies of extremely variable thickness can be traced to a depth of 150 m and along a strike for hundreds of meters. The richest ore intervals are confined to the upper parts of serpentite ores. The nickel content is 10-16%, with a depth decreases to 2%., Cobalt - 0.01-0.03%, and magnesium oxide - 20-30%. Garnierite-serpentite ores have been mined since the discovery of nickel ores in New Caledonia (1875) to the present.

at. Deposits of a linear type (Lipovskoye, Elizavetinskoye deposits, Middle Urals).

They are confined to tectonic crushing zones , along which the weathering crust penetrates to a considerable depth. The width of the ore-bearing zones is not the same, it rarely reaches several tens of meters. Sometimes there are a number of parallel stripes merging in the upper part of the crust. Most often, ore bodies have a steep fall and can be traced to a depth of 25-60 m. The main carriers of nickel mineralization in this type are garnierite and magnesium hydrosilicates , chrysotile and chrysoprase .

Fractured deposits in terms of nickel are richer than deposits of areal crust.

Deposits with a complex morphology of ore bodies.

Among these deposits are deposits of "open" and "closed" karst . Ores are confined to the contact of nickel-bearing rocks with carbonate . In this regard, the area of ​​the field is elongated along the line of contacts. Ore bodies can be traced along the contact at 100-350 m, and at a dip at 10-200 m. Karst cavities are filled with decomposed serpentite, limestone , talc , chlorite , clays , etc. The material is not sorted and has a weakly expressed rough layering . The main carriers of nickel mineralization are garnierites and other nickel silicates and halloysites .

Ore bodies in all nickel weathering deposits do not have clear boundaries. Their contours are determined according to chemical analyzes. Nickel ores complex. Useful components are: nickel, cobalt, iron (only from ores processed into ferronickel ).

According to the technological properties, the following grades are distinguished among silicate nickel ores: ferrous, siliceous, magnesian and alumina. Intermediate ferruginous-magnesian, siliceous-alumina, ferruginous-siliceous and other varieties are also distinguished.

Rich sulfide copper-nickel ores with a nickel content of more than 1% with a ratio of nickel to copper of at least 1: 1 and with a reduced (less than 25%) iron content are sent directly to the smelting. With an iron content of more than 25% and sulfur of more than 20%, rich ores are floated before smelting to separate into copper and nickel concentrates and withdraw pyrrhotite into a separate product.

Ordinary copper-nickel ores with a nickel content of less than 1% are enriched ; in this case, collective copper-nickel or selective nickel and copper concentrates are obtained. The cobalt contained in copper-nickel ores accumulates in the process of enrichment in copper-nickel, copper and nickel concentrates. Harmful impurities of sulfide copper-nickel ores are zinc , lead and arsenic ; their limit contents are established by technical conditions.

Silicate nickel ores are divided into two technological types according to the complex of ore-forming minerals: ferrous (ocherous, leptochlorite , hematite) and magnesian (serpentinites with nickel silicates). All silicate ores undergo a direct metallurgical redistribution: ferrous - hydrometallurgical (with a magnesium content of less than 3%) or pyrometallurgical methods, magnesian - only pyrometallurgical. Copper and chromium are considered harmful impurities in silicate nickel ores, and phosphorus is also smelted on ferronickel. The limiting contents of these components are determined by the technical conditions. Oxidized and mixed ores are enriched significantly worse than sulfide ores, especially those containing copper in silicate form. Zinc in oxide form is practically not recovered in commodity concentrates.

Oxidized and mixed ores are processed either according to complex combined schemes, including sulfidization of oxidized minerals and flotation of the resulting material, or by a hydrometallurgical method - by chemical leaching of metals and their subsequent deposition.

All copper, lead-zinc and copper-nickel ores are complex (see. Types of ores). During processing, they usually receive marketable copper, lead, zinc and nickel concentrates, often also sulfuric (pyrite), molybdenum , barite and magnetite , sometimes industrial products containing noble and other metals. In commodity concentrates of different grades, distinguished by the content of the main components, the content of impurities is also limited.

The bulk of mined nickel (87%) goes to the production of heat-resistant, structural, tool, stainless steels and alloys ; a relatively small part of nickel is spent on the production of nickel and copper-nickel rolled products, for the manufacture of wire, ribbons, various equipment for the chemical and food industries, as well as in jet aircraft, rocket science, in the manufacture of equipment for nuclear power plants, and for the manufacture of radar devices. Alloys of nickel with copper, zinc, aluminum ( brass , nickel silver , nickel silver , bronze ), an alloy of nickel and chromium ( nichrome ) and monel metal (75% copper and 25% nickel) are widely used in the engineering industry. The Konel alloy is used in rocket science; elinvar maintains constant elasticity at various temperatures; platinum replaces expensive platinum; permalloy has magnetic permeability. Permalloy cores are in any telephone set. A tenth of the world's nickel is used for the manufacture of catalysts in the petrochemical industry.

According to VNIIG, the total reserves of nickel in industrialized and developing countries at the beginning of 1998 amounted to 77.4 million tons, including confirmed reserves of 45.5 million tons. The main reserves are concentrated in New Caledonia , Canada , the Australian Union , the Philippines , and Indonesia , Brazil , Guatemala , Greece . Japan and the countries of Western Europe (with the exception of Norway ) do not have their own nickel resources. Insignificant nickel reserves in the USA are 140 thousand tons. The annual nickel production of industrialized and developing countries is about 600 thousand tons, including: in Canada - 262, New Caledonia - up to 135, the Australian Union - 85, in the Philippines - 40, in Indonesia - 25, South Africa - 22, USA - 15, Dominican Republic - 27. The main countries for nickel mining and production are Canada, New Caledonia and the Australian Union, and the main consumers are Japan, USA and Western Europe. In this regard, Japan, the United States and Germany are intensively addressing the problem of extraction and processing of ferromanganese nodules of the World Ocean with the aim of obtaining nickel from them. Further growth in nickel production is envisaged mainly due to nickel silicate ores and the involvement of sulfide deposits with large reserves, albeit poor ores, in the operation. Nickel occupies one of the leading places among non-ferrous metals in the volume of foreign trade.

Unique deposits contain more than 500 thousand tons of nickel, large - 500-250 thousand tons, medium - 250-100 thousand tons, small - up to 100 thousand tons.

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