Barium sulfate

Last updated
Barium sulfate
Bariumsulfatpulver.png
Barium-sulfate-2D.png
3D model of barium sulfate Barite-unit-cell-3D-vdW.png
3D model of barium sulfate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.028.896 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 231-784-4
KEGG
PubChem CID
RTECS number
  • CR060000
UNII
UN number 1564
  • InChI=1S/Ba.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 Yes check.svgY
    Key: TZCXTZWJZNENPQ-UHFFFAOYSA-L Yes check.svgY
  • InChI=1/Ba.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2
    Key: TZCXTZWJZNENPQ-NUQVWONBAD
  • [Ba+2].[O-]S([O-])(=O)=O
Properties
BaSO4
Molar mass 233.39 g/mol
Appearancewhite crystalline
Odor odorless
Density 4.49 g/cm3
Melting point 1,580 °C (2,880 °F; 1,850 K)
Boiling point 1,600 °C (2,910 °F; 1,870 K) (decomposes)
0.2448 mg/100 mL (20 °C)
0.285 mg/100 mL (30 °C)
1.0842 × 10−10 (25 °C)
Solubility insoluble in alcohol, [1] soluble in concentrated, hot sulfuric acid
−71.3·10−6 cm3/mol
1.636 (alpha)
Structure
orthorhombic
Thermochemistry
101.7 J/(mol K)
Std molar
entropy (S⦵298)
132 J/(mol·K) [2]
−1465 kJ/mol [2]
Pharmacology
V08BA01 ( WHO )
by mouth, rectal
Pharmacokinetics:
negligible by mouth
rectal
Legal status
Hazards
GHS labelling:
P260, P264, P270, P273, P314, P501
NFPA 704 (fire diamond)
NFPA 704.svgHealth 0: Exposure under fire conditions would offer no hazard beyond that of ordinary combustible material. E.g. sodium chlorideFlammability 0: Will not burn. E.g. waterInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
0
0
Flash point noncombustible [3]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp) [3]
REL (Recommended)
TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp) [3]
IDLH (Immediate danger)
N.D. [3]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Barium sulfate (or sulphate) is the inorganic compound with the chemical formula Ba SO4. It is a white crystalline solid that is odorless and insoluble in water. It occurs in nature as the mineral barite, which is the main commercial source of barium and materials prepared from it. Its opaque white appearance and its high density are exploited in its main applications. [4]

Contents

Uses

Drilling fluids

About 80% of the world's barium sulfate production, mostly purified mineral, is consumed as a component of oil well drilling fluid. It increases the density of the fluid, [5] increasing the hydrostatic pressure in the well and reducing the chance of a blowout.

Radiocontrast agent

Barium sulfate in suspension is often used medically as a radiocontrast agent for X-ray imaging and other diagnostic procedures. It is most often used in imaging of the GI tract during what is colloquially known as a "barium meal". It is administered orally, or by enema, as a suspension of fine particles in a thick milk-like solution (often with sweetening and flavoring agents added). Although barium is a heavy metal, and its water-soluble compounds are often highly toxic, the low solubility of barium sulfate protects the patient from absorbing harmful amounts of the metal. Barium sulfate is also readily removed from the body, unlike Thorotrast, which it replaced. Due to the relatively high atomic number (Z = 56) of barium, its compounds absorb X-rays more strongly than compounds derived from lighter nuclei.

Pigment

The majority of synthetic barium sulfate is used as a component of white pigment for paints. In oil paint, barium sulfate is almost transparent[ citation needed ], and is used as a filler or to modify consistency. One major manufacturer of artists' oil paint sells "permanent white" that contains a mixture of titanium white pigment (TiO2) and barium sulfate. The combination of barium sulfate and zinc sulfide (ZnS) is the inorganic pigment called lithopone. In photography it is used as a coating for certain photographic papers. [5] It is also used as a coating to diffuse light evenly.

Light-reflecting paint for cooling

Barium sulfate is highly reflective, of both visible and ultraviolet light. [6] Researchers used it as an ingredient in paint that reflects 98.1% of solar radiation, allowing surfaces to which it has been applied to stay cooler in sunlit conditions. Commercially available white paints only reflect 80 - 90% of solar radiation. [7] By using hexagonal nanoplatelet boron nitride, the thickness of a coat of this type of paint was reduced to 0.15 mm. [6]

Paper brightener

A thin layer of barium sulfate called baryta is first coated on the base surface of most photographic paper to increase the reflectiveness of the image, with the first such paper introduced in 1884 in Germany. [8] The light-sensitive silver halide emulsion is then coated over the baryta layer. The baryta coating limits the penetration of the emulsion into the fibers of the paper and makes the emulsion more even, resulting in more uniform blacks. [9] Further coatings may then be present for fixing and protection of the image. Baryta has also been used to brighten papers intended for ink-jet printing. [10]

Plastics filler

Barium sulfate is commonly used as a filler for plastics to increase the density of the polymer in vibrational mass damping applications. In polypropylene and polystyrene plastics, it is used as a filler in proportions up to 70%. It has an effect of increasing acid and alkali resistance and opacity. Such composites are also used as X-ray shielding materials due to their enhanced radio-opacity. [11] In cases where machinability and weight are a concern, composites with high mass fraction (70–80%) of barium sulfate may be preferred to the more commonly used steel shields. [12]

Barium sulfate can also be used to enhance the material properties of HDPE, [13] although typically in relatively low concentrations, and often in combination with other fillers like calcium carbonate or titanium oxide.

Niche uses

Barium sulfate is used in soil testing. Tests for soil pH and other qualities of soil use colored indicators, and small particles (usually clay) from the soil can cloud the test mixture and make it hard to see the color of the indicator. Barium sulfate added to the mixture binds with these particles, making them heavier so they fall to the bottom, leaving a clearer solution.

In colorimetry, barium sulfate is used as a near-perfect diffuser when measuring light sources.

In metal casting, the moulds used are often coated with barium sulfate in order to prevent the molten metal from bonding with the mould.

It is also used in brake linings, anacoustic foams, powder coatings, and root canal filling.

Barium sulfate is an ingredient in the "rubber" pellets used by Chilean police. [14] This together with silica helps the pellet attain a 96.5 Shore A hardness. [14]

Catalyst support

Barium sulfate is used as a catalyst support when selectively hydrogenating functional groups that are sensitive to overreduction. With a low surface area, the contact time of the substrate with the catalyst is shorter and thus selectivity is achieved. Palladium on barium sulfate is also used as a catalyst in the Rosenmund reduction.

Pyrotechnics

As barium compounds emit a characteristic green light when heated at high temperature, barium salts are often used in green pyrotechnic formulas, although nitrate and chlorate salts are more common. Barium sulfate is commonly used as a component of "strobe" pyrotechnic compositions.

Copper industry

As barium sulfate has a high melting point and is insoluble in water, it is used as a release material in casting of copper anode plates. The anode plates are cast in copper molds, so to avoid the direct contact of the liquid copper with the solid copper mold, a suspension of fine barium sulfate powder in water is used as a coating on the mold surface. Thus, when the molten copper solidifies in form of an anode plate it can be easily released from its mold.

Radiometric measurements

Barium sulfate is sometimes used, besides polytetrafluoroethylene (PTFE), to coat the interior of integrating spheres due to the high reflectance of the material and near Lambertian characteristics.

3D printing of firearms

Barium sulfate is listed among the materials acceptable to the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) for the manufacturing of firearms and/or components that are made of plastic, to achieve compliance with the U.S. federal requirement that an X-ray machine must be able to accurately depict the shape of the plastic firearm or component. [15]

Production

Almost all of the barium consumed commercially is obtained from barite, which is often highly impure. Barite is processed by thermo-chemical sulfate reduction (TSR), also known as carbothermal reduction (heating with coke) to give barium sulfide:

BaSO4 + 4 C → BaS + 4 CO

In contrast to barium sulfate, barium sulfide is soluble in water and readily converted to the oxide, carbonate, and halides. To produce highly pure barium sulfate, the sulfide or chloride is treated with sulfuric acid or sulfate salts:

BaS + H2SO4 → BaSO4 + H2S

Barium sulfate produced in this way is often called blanc fixe, which is French for "permanent white". Blanc fixe is the form of barium encountered in consumer products, such as paints. [5]

In the laboratory barium sulfate is generated by combining solutions of barium ions and sulfate salts. Because barium sulfate is the least toxic salt of barium due to its insolubility, wastes containing barium salts are sometimes treated with sodium sulfate to immobilize (detoxify) the barium. Barium sulfate is one of the most insoluble salts of sulfate. Its low solubility is exploited in qualitative inorganic analysis as a test for Ba2+ ions, as well as for sulfate.

Untreated raw materials such as natural baryte formed under hydrothermal conditions may contain many impurities, a.o., quartz, or even amorphous silica. [16]

History

Barium sulfate is reduced to barium sulfide by carbon. The accidental discovery of this conversion many centuries ago led to the discovery of the first synthetic phosphor. [4] The sulfide, unlike the sulfate, is water-soluble.

During the early part of the 20th century, during the Japanese colonization period, hokutolite was found to exist naturally in the Beitou hot-springs area near Taipei City, Taiwan. Hokutolite is a radioactive mineral composed mostly of PbSO4 and BaSO4, but also containing traces of uranium, thorium and radium. The Japanese harvested these elements for industrial uses, and also developed dozens of “therapeutic hot-spring baths” in the area. [17]

Safety aspects

Although soluble salts of barium are moderately toxic to humans, barium sulfate is nontoxic due to its insolubility. The most common means of inadvertent barium poisoning arises from the consumption of soluble barium salts mislabeled as BaSO4. In the Celobar incident (Brazil, 2003), nine patients died from improperly prepared radiocontrast agent. In regards to occupational exposures, the Occupational Safety and Health Administration set a permissible exposure limit at 15 mg/m3, while the National Institute for Occupational Safety and Health has a recommended exposure limit at 10 mg/m3. For respiratory exposures, both agencies have set an occupational exposure limit at 5 mg/m3. [18]

See also

Related Research Articles

<span class="mw-page-title-main">Barium</span> Chemical element with atomic number 56 (Ba)

Barium is a chemical element; it has symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element.

<span class="mw-page-title-main">Baryte</span> Barium sulfate mineral

Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate (BaSO4). Baryte is generally white or colorless, and is the main source of the element barium. The baryte group consists of baryte, celestine (strontium sulfate), anglesite (lead sulfate), and anhydrite (calcium sulfate). Baryte and celestine form a solid solution (Ba,Sr)SO4.

Sulfide (also sulphide in British English ) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. Sulfide also refers to large families of inorganic and organic compounds, e.g. lead sulfide and dimethyl sulfide. Hydrogen sulfide (H2S) and bisulfide (SH−) are the conjugate acids of sulfide.

<span class="mw-page-title-main">Lead(II) sulfate</span> Chemical compound

Lead(II) sulfate (PbSO4) is a white solid, which appears white in microcrystalline form. It is also known as fast white, milk white, sulfuric acid lead salt or anglesite.

<span class="mw-page-title-main">Barium hydroxide</span> Chemical compound

Barium hydroxide is a chemical compound with the chemical formula Ba(OH)2. The monohydrate (x = 1), known as baryta or baryta-water, is one of the principal compounds of barium. This white granular monohydrate is the usual commercial form.

<span class="mw-page-title-main">Sodium sulfate</span> Chemical compound with formula Na2SO4

Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 million tonnes, the decahydrate is a major commodity chemical product. It is mainly used as a filler in the manufacture of powdered home laundry detergents and in the Kraft process of paper pulping for making highly alkaline sulfides.

<span class="mw-page-title-main">Barium carbonate</span> Chemical compound

Barium carbonate is the inorganic compound with the formula BaCO3. Like most alkaline earth metal carbonates, it is a white salt that is poorly soluble in water. It occurs as the mineral known as witherite. In a commercial sense, it is one of the most important barium compounds.

<span class="mw-page-title-main">Barium chloride</span> Chemical compound

Barium chloride is an inorganic compound with the formula BaCl2. It is one of the most common water-soluble salts of barium. Like most other water-soluble barium salts, it is a white powder, highly toxic, and imparts a yellow-green coloration to a flame. It is also hygroscopic, converting to the dihydrate BaCl2·2H2O, which are colourless crystals with a bitter salty taste. It has limited use in the laboratory and industry.

<span class="mw-page-title-main">Cadmium sulfate</span> Chemical compound

Cadmium sulfate is the name of a series of related inorganic compounds with the formula CdSO4·xH2O. The most common form is the monohydrate CdSO4·H2O, but two other forms are known CdSO4·8⁄3H2O and the anhydrous salt (CdSO4). All salts are colourless and highly soluble in water.

<span class="mw-page-title-main">Barium nitrate</span> Chemical compound

Barium nitrate is the inorganic compound with the chemical formula Ba(NO3)2. It, like most barium salts, is colorless, toxic, and water-soluble. It burns with a green flame and is an oxidizer; the compound is commonly used in pyrotechnics.

Lithopone, C.I. Pigment White 5, is a mixture of inorganic compounds, widely used as a white pigment powder. It is composed of a mixture of barium sulfate and zinc sulfide. These insoluble compounds blend well with organic compounds and confer opacity. It was made popular by the cheap production costs, greater coverage. Related white pigments include titanium dioxide, zinc oxide, zinc sulfide, and white lead.

Chrome yellow is a bright, warm yellow pigment that has been used in art, fashion, and industry. It is the premier orange pigment for many applications.

<span class="mw-page-title-main">Copper(II) hydroxide</span> Hydroxide of copper

Copper(II) hydroxide is the hydroxide of copper with the chemical formula of Cu(OH)2. It is a pale greenish blue or bluish green solid. Some forms of copper(II) hydroxide are sold as "stabilized" copper(II) hydroxide, although they likely consist of a mixture of copper(II) carbonate and hydroxide. Cupric hydroxide is a strong base, although its low solubility in water makes this hard to observe directly.

<span class="mw-page-title-main">Zinc chromate</span> Chemical compound

Zinc chromate, ZnCrO4, is a chemical compound, a salt containing the chromate anion, appearing as odorless yellow powder or yellow-green crystals, but, when used for coatings, pigments are often added. It is used industrially in chromate conversion coatings, having been developed by the Ford Motor Company in the 1920s.

<span class="mw-page-title-main">Barium sulfide</span> Chemical compound

Barium sulfide is the inorganic compound with the formula BaS. BaS is the barium compound produced on the largest scale. It is an important precursor to other barium compounds including BaCO3 and the pigment lithopone, ZnS/BaSO4. Like other chalcogenides of the alkaline earth metals, BaS is a short wavelength emitter for electronic displays. It is colorless, although like many sulfides, it is commonly obtained in impure colored forms.

<span class="mw-page-title-main">Strontium carbonate</span> Chemical compound

Strontium carbonate (SrCO3) is the carbonate salt of strontium that has the appearance of a white or grey powder. It occurs in nature as the mineral strontianite.

<span class="mw-page-title-main">Barium bromide</span> Chemical compound

Barium bromide is the chemical compound with the formula BaBr2. It is ionic and hygroscopic in nature.

Oilfield scale inhibition is the process of preventing the formation of scale from blocking or hindering fluid flow through pipelines, valves, and pumps used in oil production and processing. Scale inhibitors (SIs) are a class of specialty chemicals that are used to slow or prevent scaling in water systems. Oilfield scaling is the precipitation and accumulation of insoluble crystals (salts) from a mixture of incompatible aqueous phases in oil processing systems. Scale is a common term in the oil industry used to describe solid deposits that grow over time, blocking and hindering fluid flow through pipelines, valves, pumps etc. with significant reduction in production rates and equipment damages. Scaling represents a major challenge for flow assurance in the oil and gas industry. Examples of oilfield scales are calcium carbonate (limescale), iron sulfides, barium sulfate and strontium sulfate. Scale inhibition encompasses the processes or techniques employed to treat scaling problems.

<span class="mw-page-title-main">Europium(II) sulfate</span> Chemical compound

Europium(II) sulfate is the inorganic compound with the formula EuSO4. Two polymorphs are known, α and the more stable β. Both are colorless. The β polymorph is isostructural with barium sulfate, hence it is insoluble in water. The salt is generated by addition of soluble europium(II) salts to dilute sulfuric acid.

References

  1. ↑ CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. 2004. pp.  4–45. ISBN   0-8493-0485-7.
  2. 1 2 Zumdahl, Steven S. (2009). Chemical Principles (6th ed.). Houghton Mifflin Company. ISBN   978-0-618-94690-7.
  3. 1 2 3 4 NIOSH Pocket Guide to Chemical Hazards. "#0047". National Institute for Occupational Safety and Health (NIOSH).
  4. 1 2 Holleman, A. F. and Wiberg, E. (2001) Inorganic Chemistry, San Diego, CA. Academic Press, ISBN   0-12-352651-5.
  5. 1 2 3 Kresse, Robert; Baudis, Ulrich; Jäger, Paul; Riechers, H. Hermann; Wagner, Heinz; Winkler, Jochen; Wolf, Hans Uwe (2007). "Barium and Barium Compounds". Ullmann's Encyclopedia of Industrial Chemistry. doi:10.1002/14356007.a03_325.pub2. ISBN   978-3-527-30673-2.
  6. 1 2 Puiu, Tibi (2022-10-04). "World's whitest paint is now thin enough to coat and cool down cars, trains and planes". ZME Science. Retrieved 2022-10-12.
  7. ↑ Wiles, Kayla (September 16, 2021). "Purdue record for the whitest paint appears in latest edition of 'Guinness World Records'". purdue.edu. Retrieved 2022-10-12.
  8. ↑ The Getty Conservation Institute, Silver Gelatin. The Atlas of Analytical Signatures of Photographic Processes. J. Paul Getty Trust, 2013.
  9. ↑ Salvaggio, Nanette L. Basic Photographic Materials and Processes. Taylor & Francis US, Oct 27, 2008. p. 362.
  10. ↑ Nikitas, Theano. "Inkjet papers that will give your photos pizzazz: are you and your clients bored with your photo prints? check out our favorite fine-art and specialty inkjet papers that are sure to make your images stand out." Photo District News July 2012: 36+. General Reference Center GOLD. Web. 3 November 2012
  11. ↑ Lopresti, Mattia; Alberto, Gabriele; Cantamessa, Simone; Cantino, Giorgio; Conterosito, Eleonora; Palin, Luca; Milanesio, Marco (28 January 2020). "Light Weight, Easy Formable and Non-Toxic Polymer-Based Composites for Hard X-ray Shielding: A Theoretical and Experimental Study". International Journal of Molecular Sciences. 21 (3): 833. doi: 10.3390/ijms21030833 . PMC   7037949 . PMID   32012889.
  12. ↑ Lopresti, Mattia; Alberto, Gabriele; Cantamessa, Simone; Cantino, Giorgio; Conterosito, Eleonora; Palin, Luca; Milanesio, Marco (2020-01-28). "Light Weight, Easy Formable and Non-Toxic Polymer-Based Composites for Hard X-ray Shielding: A Theoretical and Experimental Study". International Journal of Molecular Sciences. 21 (3): 833. doi: 10.3390/ijms21030833 . ISSN   1422-0067. PMC   7037949 . PMID   32012889.
  13. ↑ Chen, X.; Wang, L.; Shi, J.; Shi, H.; Liu, Y. (2010). "Effect of Barium Sulfate Nanoparticles on Mechanical Properties and Crystallization Behaviour of HDPE". Polymers & Polymer Composites. 18 (3): 145-152. doi:10.1177/096739111001800304.
  14. 1 2 "Investigación U. de Chile comprueba que perdigones usados por Carabineros contienen solo 20 por ciento de goma". Universidad de Chile. November 18, 2019. Retrieved June 29, 2020.
  15. ↑ "Is a firearm illegal if it is made out of plastic?". September 23, 2016. Retrieved March 4, 2023.
  16. ↑ Fedele, L.; Todesca, R.; Boni, M. (1 February 2003). "Barite-silica mineralization at the inter-Ordovician unconformity in southwestern Sardinia (Italy): a fluid inclusion study". Mineralogy and Petrology. 77 (3–4): 197–213. Bibcode:2003MinPe..77..197F. doi:10.1007/s00710-002-0200-9. S2CID   129874363.
  17. ↑ Chu, Tieh-Chi; Wang, Jeng-long (2000). "Radioactive Disequilihrium of Uranium and Thorium Nuclide Series in Hot Spring and River Water from Peitou Hot Spring Basin in Taipei". Journal of Nuclear and Radiochemical Sciences. 1 (1): 5–10. doi: 10.14494/jnrs2000.1.5 .
  18. ↑ "Barium Sulfate". NIOSH Pocket Guide to Chemical Hazards. Centers for Disease Control and Prevention. April 4, 2011. Retrieved November 18, 2013.
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