pyrites

(redirected from pyritic)
Also found in: Dictionary, Thesaurus.

pyrites

1. another name for pyrite
2. any of a number of other disulphides of metals, esp of copper and tin

Pyrites

 

pyrite ores consisting predominantly of sulfurous (sulfide) ore minerals. The composition of pyrites is dominated by iron sulfides (pyrite, pyrrhotite, marcasite). Also present are the sulfides of copper (chalcopyrite, bornite), zinc (sphalerite), and lead (galenite) and barium sulfate (barite). Pyrite deposits consist of massive as well as disseminated ores. These deposits have the shape of beds, lenses, stocks, and veins measuring up to 5,000 m long and 250 m thick; they occur at depths of as much as 2,000 m.

In terms of formation and occurrence, pyrites are closely linked to the basic and alkaline igneous rocks that issued onto the floor of ancient seas and formed extended ophiolite zones characteristic of the early stage of geosynclinal development. In the volcanic zones, pyrites form discontinuous chains measuring up to several thousand kilometers long. Pyrites arise in the late stage of volcanic cycles, when the eruption of the primary magma has been replaced by alkaline and acidic lavas, which are accompanied by the heavy venting of volcanic gaseous and liquid solutions. The solutions carry a large amount of metals that combine with the sulfurous sublimates and are deposited in the form of sulfides, creating the pyrites. That portion of the pyrites that arises along the seepage paths of the solutions through the volcanic rock forms hydrothermal metasomatic deposits. The other part of the mineral matter carried by the volcanic solutions reaches the floor of the sea and, in being deposited here, creates the volcanogenic sedimentary deposits of pyrites.

The accumulation of pyrites occurs over a long period of time, and in the early stages, predominantly the sulfurous iron compounds form, which are of limited practical interest. The pyrite deposits of copper, zinc, and lead arise in the later stages.

In the USSR the following pyrite deposits are known: Proterozoic (Karelia), Lower Paleozoic (Buriatia and Tuva), Middle and Upper Paleozoic (Urals and Caucasus), and Mesozoic and Cenozoic (Caucasus) deposits. Abroad, there are Proterozoic (Canada), Lower Paleozoic (Norway and Australia), Middle and Upper Paleozoic (Spain, Portugal), Mesozoic (Yugoslavia), and Cenozoic (Japan, Turkey, Greece, Cuba) deposits.

Pyrite deposits are an important source for obtaining copper, zinc, and lead and, in part, gold, silver, bismuth, cadmium, indium, barium, selenium, sulfur, and sulfuric acid.

REFERENCE

Genezis endogennykh rudnykh mestorozhdenii. Moscow, 1968.

V. I. SMIRNOV

References in periodicals archive ?
In addition, the sulfur partitioning capabilities of these units were exploited to ensure that nearly all of the high density pyritic sulfur was captured in the cyclone underflows.
1978, Mossbauer studies of coal and coke: quantitative phase identification and direct determination of pyritic and iron sulphide sulphur content.
Gold-bearing pyritic replacement bodies are found adjacent to faults or quartz-pyrite veins.
Acid sulfate soil (ASS) scalds are persistently bare areas, usually found on low-elevation (0-1 m Australian Height Datum) coastal floodplains, associated with severe acidification resulting from the drainage (aeration and oxidation) of pyritic sediments.
The pyritic orebodies occur as massive, stratabound deposits near volcanic centers, either overlying volcanic rocks or intercalated with shales and tuffs (Strauss and Madel, 1974).
As the slurry moves through the unit, the large pyritic sulfur particles settle out in a physical cleaning step, and the smaller particles still attached to the coal nuggets are solubilized by the microbes.
Oversized shale partings, pyritic rock and other impurities are then rejected across a Midwestern Uni-Rod screen with 2-inch wire cloth apertures.
Total sulphur and different forms of sulphur (sulphide sulphur, sulphate sulphur, pyritic sulphur and organic sulphur) in solid semicoke were determined according to the Estonian standard EVS 664:1995 for solid fuels [7].
Alternatively these results suggest that burial of the pyritic material below material that has a biological oxygen sink will be effective in reducing the rate of oxidation.
It can recover and upgrade coal lost in the final washery fines waste stream, and remove pyritic sulphur and ash to enhance the market value of coal fines.
Initially the autoclave circuit was designed to employ a recycle stream from the autoclave wash thickeners to dilute the pyritic sulphur content and decompose the carbonate prior to pressure oxidation.