Baryte or barite (BaSO4) is a mineral consisting of barium sulfate. The baryte group consists of baryte, celestine, anglesite and anhydrite. Baryte is generally white or colorless, and is the main source of barium. Baryte and celestine form a solid solution (Ba,Sr)SO4.
The American Petroleum Institute specification API 13/ISO 13500, which governs baryte for drilling purposes, does not refer to any specific mineral, but rather a material that meets that specification. In practice, however, this is usually the mineral baryte.
The term "primary barytes" refers to the first marketable product, which includes crude baryte (run of mine) and the products of simple beneficiation methods, such as washing, jigging, heavy media separation, tabling, flotation. Most crude baryte requires some upgrading to minimum purity or density. Baryte that is used as an aggregate in a "heavy" cement is crushed and screened to a uniform size. Most baryte is ground to a small, uniform size before it is used as a filler or extender, an addition to industrial products, in the production of barium chemicals or a weighting agent in petroleum well drilling mud.
The name baryte is derived from the Ancient Greek: βαρύς, translit. barús, 'heavy'. The American spelling is barite. The International Mineralogical Association initially adopted "barite" as the official spelling, but recommended adopting the older "baryte" spelling later. This move was controversial and was notably ignored by American mineralogists.
Baryte occurs in a large number of depositional environments, and is deposited through a large number of processes including biogenic, hydrothermal, and evaporation, among others. Baryte commonly occurs in lead-zinc veins in limestones, in hot spring deposits, and with hematite ore. It is often associated with the minerals anglesite and celestine. It has also been identified in meteorites.
Baryte has been found at locations in Brazil, Nigeria, Canada, Chile, China, India, Pakistan, Germany, Greece, Guatemala, Iran, Ireland (where it was mined on Benbulben), Liberia, Mexico, Morocco, Peru, Romania (Baia Sprie), Turkey, South Africa (Barberton Mountain Land), Thailand, UK (Cornwall, Cumbria, Dartmoor/Devon, Derbyshire, Durham, Perthshire, Argyllshire and Surrey) and in the US from Cheshire, Connecticut, De Kalb, New York and Fort Wallace, New Mexico. It is mined in Arkansas, Connecticut, Virginia, North Carolina, Georgia, Tennessee, Kentucky, Nevada and Missouri.
World baryte production for 2016 was 7.3 million tonnes. The major barytes producers (in thousand tonnes, data for 2016) are as follows: China (3,100), India (1,300), Morocco (550), United States (430), Turkey (240), Russia (210), Mexico (200), Iran (200), Kazakhstan (190) and Thailand (160).
The main users of barytes in 2016 were (in million tonnes) Middle East (1.74), US (1.60), China (1.50), the European Union and Norway (0.65), Russia and CIS (0.45), South America (0.28), India (0.25), and Africa (0.17).
Worldwide, 69–77% of baryte is used as a weighting agent for drilling fluids in oil and gas exploration to suppress high formation pressures and prevent blowouts. As a well is drilled, the bit passes through various formations, each with different characteristics. The deeper the hole, the more baryte is needed as a percentage of the total mud mix. An additional benefit of baryte is that it is non-magnetic and thus does not interfere with magnetic measurements taken in the borehole, either during logging-while-drilling or in separate drill hole logging. Baryte used for drilling petroleum wells can be black, blue, brown or gray depending on the ore body. The baryte is finely ground so that at least 97% of the material, by weight, can pass through a 200-mesh (75 μm) screen, and no more than 30%, by weight, can be less than 6 μm diameter. The ground baryte also must be dense enough so that its specific gravity is 4.2 or greater, soft enough to not damage the bearings of a tricone drill bit, chemically inert, and containing no more than 250 milligrams per kilogram of soluble alkaline salts. In August 2010 API (American Petroleum Institute) published specifications to modify the 4.2 drilling grade standards for baryte to include 4.1 SG materials.
In the deep ocean, away from continental sources of sediment, pelagic baryte precipitates and forms a significant amount of the sediments. Since baryte has oxygen, systematics in the δ18O of these sediments have been used to help constrain paleotemperatures for oceanic crust.
The variations in sulfur isotopes (34S/32S) are being examined in evaporite minerals containing sulfur (ex, baryte) and carbonate associated sulfates (CAS) to determine past seawater sulfur concentrations which can help identify specific depositonal periods such as anoxic or oxic conditions. The use of sulfur isotope reconstruction is often paired with oxygen when a molecule contains both elements.
Baryte is used in added-value applications which include filler in paint and plastics, sound reduction in engine compartments, coat of automobile finishes for smoothness and corrosion resistance, friction products for automobiles and trucks, radiation-shielding cement, glass ceramics and medical applications (for example, a barium meal before a contrast CAT scan). Baryte is supplied in a variety of forms and the price depends on the amount of processing; filler applications commanding higher prices following intense physical processing by grinding and micronising, and there are further premiums for whiteness and brightness and color. It is also used to produce other barium chemicals, notably barium carbonate which is used for the manufacture of LED glass for television and computer screens (historically in cathode ray tubes); and for dielectrics.
It is also sometimes used as gemstone.
|Wikisource has the text of the 1911 Encyclopædia Britannica article Barytes.|
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