Barium sulphate

The reaction of atomic number 56 sulfate in urine is an ionization reaction: solvated ions (ions in solvent) are formed from an insoluble hurried.

From: Analytical Chemistry , 1979

Powders and Inorganic Materials

Y. Nonomura , in Cosmetic Skill and Engineering, 2017

14.2.1.1.5 Barium Sulfate

Blanc fixe, BaSO 4, is made by reacting barium hydrated oxide and former atomic number 56 sources with element acid and has a aware history as a semitransparent white pigment. Barium sulfate can be formed in various shapes such A planar, starred, or spherical structures depending along the conceptualisation experimental condition, especially the supersaturation of its barium source, and the internal pore size also changes. 18 Two-dimensional barium sulphate shows especially high carnalit, and when applied to the pelt IT non lone has a smooth feeling but besides has a high unaccented-scattering attribute, showing a soft-focus effect that makes small wrinkles and pores less open. 19

Read full chapter

URL:

https://WWW.sciencedirect.com/scientific discipline/clause/pii/B9780128020050000148

Group 16 (O, S, Se, Te) Alkaline Earth Compounds

R.C. Ropp , in Encyclopedia of the Alkaline Earth Compounds, 2013

Blanc fixe

Barium sulphate has the molecular formula of BaSO 4 and the molecular weight of 233.3896   g/mol. It can cost prepared aside the response of atomic number 56 carbonate and sulfuric acid:

BaCO3  +   H2And then4 ⇒ BaSO4  +   CO2  +   H2O

Barium sulfate is a soft crystalline solid. It is a rhombic crystal. The native salt is white-hot but the color of the petrified "barite" can alter betwixt red, yellow, gray or green, depending on impurities. Its compactness is 4.50   g/cm3 and its index of refraction is 1.64. It melts around 1580   °C but decomposes in a higher place 1600   °C. Its rigorousness is 4.3 to 4.6 Mohs. It is well-nigh insoluble in water (285   magnesium/l at 30   °C) and insoluble in intoxicant. Its K sp is 1.1   ×   10–10. It is fat-soluble in concentrated vitriol. The crystal structure of BaSO4 is known to be parallelogram, with a space group pnma. The lattice parameters are: a  =   8.896   Å, b  =   5.462°, c  =   7.171   Å, V  =   348.4   Å3. Its three-dimensional complex body part is shown in Fig. 3.33.

FIGURE 3.33.

Atomic number 38 sulfate has an isotropic complex body part. Thernodynamic constants are given by the shadowing board. These values are for 293   K (Mesa 3.14).

Put of 3.14.

Thermochemical properties
ΔHƒ   =   –352.3   kcal/mol
ΔG f  =   –325.7   kcal/mol
S 0  =   31.6   cal/stage mole
C p  =   24.3   cal/degree mol
ΔH fusion  =   9.71   kcal/mol

Physical blanc fixe is widely distributed in nature and occurs as the stuff "barite" (also known Eastern Samoa barytes or heavy spar). It often associated with opposite all-metal ores, such As fluorspar. Barites containing over 94% BaSO4 can exist refined economically. It besides contains silica, metallic element oxide and fluoride impurities. Silica is the prime impurity that can be removed as atomic number 11 fluorosilicate aside treatment with hydrofluoric acid followed by virulent soda. Very pure Ba sulfate may be obtained by treating an aqueous solution of a soluble Ba salt with sodium sulphate:

BaCl2  +   Na2Sol4 ⇒ BaSO4  +   2NaCl

Barium sulfate is i of the most insoluble salts of the alkaline earths. It does not go through double decomposition reaction reactions in aqueous phase like its Mg homologue. It dissolves in concentrated H2SO4 to form an acid sulphate that breaks down to BaSO4 upon dilution. Reduction with snow under heating produces barium sulfide:

BaSO4  +   3C   ⇒   BaS   +   2CO   +   CO2

The accidental discovery of this conversion more centuries agone led to the find of the first luminescent corporate in 1803. The sulfide, unlike the sulphate, is water soluble. Sometime prior to the autumn of 1803, the Englishman John Dalton was able to explain the results of both of his studies by forward that matter is composed of atoms and that all samples of whatsoever given compound consist of the same combination of these atoms. Dalton also noted that in a series of compounds like barium sulphate, the ratios of the multitude of the second constituent that coalesce with a given weight of the first element can be reduced to lowly whole numbers pool (the law of multiple proportions). This was promote evidence for the existence of "atoms".

BaSO4 reacts violently when het up with aluminum or explosively when mixed with atomic number 19. Sulfamic acid, HSO3NH2 is a moderately strong acid. Water solutions are unstable and slowly hydrolyze to NH4HSO4. It has been used to produce nanosized barium sulfate particles.

Barium sulfate has many commercial applications. It is used either as lifelike barite, or precipitated BaSO4. The precipitated SALT in combination with equimolar amount of CO-precipitated zinc sulfide formerly was put-upon as a Stanford White antifouling covering pigment, glorious as "lithopone". Likewise, in compounding with atomic number 11 sulphide, it is used to produce fine pigment particles of uniform size, known as "blanc fixe". Natural barite, however, has greater commercial application than the precipitated salt. Information technology is used as an accumulative in drilling mud in crude anele, well trained to lubricate and unagitated the drilling bit, and to plaster the walls of the drill hole to prevent caving. It is used as a makeweight in automotive paints, plastics and galosh products. It likewise is used as a makeweight in ployurethan foam shock mats, white sidewall rubber tires and As a flux and addible to glass to step-up the refractile index.

Barium sulfate is oft used clinically as a contrast factor for X-ray photograp imaging and different diagnostic procedures. It is most often exploited in mental imagery of the GI tract. It is administered, by word of mouth or by enema, as a abatement of fine particles in an liquid solution. Although barium, and its piddle-soluble compounds are often extremely toxic, the extremely low solubility of barium sulphate protects the affected role from gripping unsafe amounts of the metal. Barium sulfate is too pronto removed from the physical structure, unlike prior compounds, which IT replaced. Its absorbance of X-rays is also high.

Blanc fixe mixtures are used as dilute pigment for paints. In oil paint, blanc fixe is all but clear, and is used as a filler or to modify consistency. One major manufacturing business of artists' oil paint sells "permanent white" that contains a mix of Ti bloodless pigment and blanc fixe. Barium sulfate itself is called blanc fixe (French for "permanent white").

A scientific-grade, barium sulfate-based paint is offered for sale that exhibits near-perfect diffuse coefficient of reflection at levels up to 98% in the UV-VIS-NIR wavelength set out. It is applied by spray painting to all but whatever substrate (metals, plastics, chicken feed) for use in integrating spheres, laser cavities, lamp reflectors and display backlights. It is characterized by a near-perfect Lambertian (i.e. diffuse) reflectance of up to 98% in the phantasmal scope from 250 to 2500   nm.

Other chemical applications of atomic number 56 sulfate are used as a pigment for photographic paper. It is also wont to prepare many former barium salts. It is available in many forms commercially.

Read full chapter

Uniform resource locator:

https://www.sciencedirect.com/scientific discipline/article/pii/B978044459550800003X

Compounds and Composite Materials

Gilbert Stuart Green Ph.D. , in Glance Biomaterials Handbook, 2012

3.2.6 Powder Summational for Image Contrast

Blanc fixe (chemical formula BaSO 4) powder is efficient as an Roentgen ray absorber. It is added as a means of producing X-beam of light contrast, so that normally radiolucent (X-ray invisible) PEEK artifacts are rendered some visibility under X-ray review in vivo. It is introduced to PEEK polymer by extrusion compounding (see Section 3.4.1 for a description of this process) to achieve an even distribution of particles, as illustrated in the electron micrograph of a fracture surface shown in Al-Jama'a al-Islamiyyah al-Muqatilah bi-Libya. 3.8.

Figure 3.8. Electron micrograph of fractured blanc fixe PEEK compound illustrating the uniform distribution of pulverise.

The effect along the stage of X-ray absorption (as evidenced by incorporative amounts of evident image contrast) of adding greater amounts of barium sulphate to Glint seat be seen in a standard contour shown in Common fig. 3.9. Here the PEEK compounds containing 4%, 6%, and 20% by weight of barium sulfate powder have been molded into orthogonal pieces at different thicknesses ranging from 2 to 10 mm in 2 millimeter increments and assembled in the govern shown. Adjacent to these is a machined atomic number 13 "stepped wedge" of the same dimensions away agency of comparison. It can be seen that the compound containing 20% atomic number 56 sulphate matches very close the radiopacity of the metal at the likes of-for-like thicknesses. By selecting compounds containing 4%, 6%, or 20% barium sulphate, the plant developer can, thence, tailor the amount of radiopacity of the device to achieve an optimized level of contrast. The radiographs shown in Common fig. 3.10 illustrate this for PEEK-OPTIMA polymer spinal fusion cages that have been made with no additive and 6% and 20% image contrast additive, respectively, compared with a argentiferous cage.

Shape 3.9. Peep-OPTIMA X-ray contrast grades compared with aluminum-stepped wedge.

 Courtesy of Invibio.

Chassis 3.10. Spinal fusion cages made from PEEK-OPTIMA image demarcation grades implanted in phantom.

 Photo courtesy of Invibio.

Substantially, American Samoa a consequence of their shape, powders ut not enhance the tensile strength of polymer materials compared with fibre reinforcements, although there are somatogenic changes to the substructure polymer that occur as a result of their increase. Table 3.2 compares the mechanical properties of barium sulphate-filled PEEK with unfilled Peep. It can be seen that increasing the amount of makeweight really reduces the tensile strength of the material from 100 through 95 MPa, to 90 MPa with the highest filler loading. This enduringness reduction is outgrowth past the beneficial bring i in X-ray contrast, which, arsenic has been illustrated, increases with increasing amounts of additive.

Table 3.2. Mechanical Properties of PEEK-OPTIMA Image Counterpoint Grades

Prop Quiz Method acting Units PEEK-OPTIMA Unfilled PEEK-OPTIMA Image Contrast Grade (Low Radiopacity) PEEK-OPTIMA Image Contrast Grad (Screaky Radiopacity)
Tensile strong poin ISO 527 MPa 100 95 90
Tensile elongation ISO 527 % 20 20 15
Flexural modulus ISO 178 Grade point average 4 3.8 4.5
Flexural strength ISO 178 MPa 170 150 150
Notched Izod impact ISO 180 kJ/m2 7.6 7 8
Specific gravity ISO 1183 g/cc 1.3 1.36 1.49

As an alternate method to adding radiopaque powder, all-metal wires (markers) may also be added to PEEK (particularly to PEEK composites) to make them seeable radiographically. This testament be described in more point in Department 3.5.2.2, although information technology is, mayhap, appropriate to reveal a radiograph in this surgical incision of this form of Peep composite material. Figure 3.11 compares the image contrast achieved with CFR PEEK (containing electrify markers) with that for titanium and CFR Glance (with no markers) under X-ray inspection.

Figure 3.11. X ray of metallic and composite plant screws with and without markers implanted in apparition.

 Photo courtesy of Icotec.

Read full chapter

URL:

https://World Wide Web.sciencedirect.com/science/clause/pii/B978143774463710003X

Pigments for paint

A.G. Niels Abel , in Blusher and Airfoil Coatings (Second Edition), 1999

3.12.11.4 Atomic number 56 sulphate (natural — barytes; synthetic substance — barium sulphate)

Colouration Index — Barytes, CI Pigment White 22; barium sulfate, CI Pigment White 21.

Convention — BaSO4.

Barium sulfate is very inert, insoluble and stable to light and heat. The lifelike form is obtained as the mineral 'barite'. After being crushed, wet and dried it is usually micronized, reducing its particle size from 25 µm to 2–10 µm, frankincense aiding its dispersibility. The synthetic edition is made past reacting open Ba compounds with sulfuric acid operating room soluble sulphate salts, and has a better texture than the natural grades, giving information technology a higher oil absorption.

Its refractive index (1.64) is higher than other extenders, which gives it both pigmentary properties. Its countertenor density is as wel useful for paints sold by weight. It is used in primers, undercoats, and industrial finishes, where it hardens the take. Its high density leads to information technology having a tendency to ensconce. In spite of IT organism a Ba salt, its insolubility ensures it is non-toxic.

Register full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B9781855733480500082

Fillers and reinforcements

Clive Maier , Teresa Calafut , in Polypropylene, 1998

4.3 Barite

Barium sulfate ( Figure 4.3), commonly named heavy spar, is launch in the hydrothermal veins of cavity fissures in limestones, sandstone, shales, operating theater clays or as rise up deposits resulting from limestone weathering. Barite light depends on line; brown buff barite (brightness 80–85) is found in Nevada, Missouri, Georgia, Illinois, and United Mexican States, while pigment grade Stanford White barium sulphate (luminosity 92–94) is obtained almost exclusively from China. [942]

Barites are the all but chemically nonabsorbent of the usually misused minerals in polypropylene (Ca carbonate, talc, isinglass, and barite; Table 4.1), with first-class resistance to acids, alkali, and every last known organic solvents. Due to a 60% high specific gravity, loadings are low compared to other mineralized fillers, and the effect on physical properties of the full resin is not as articulate. Barite has a high physical phenomenon index than else minerals. It is utilized in heavier parts or for applications that expect sound deadening or corrosion immunity. [942]

Read untouched chapter

URL:

https://web.sciencedirect.com/skill/article/pii/B9781884207587500096

Spectrophotometry

Andreas Höpe , in Experimental Methods in the Physical Sciences, 2014

6.6.2.2 BaSO4-Based Standards

Barium sulphate is a white crystalline powder. Because of its broad electron denseness, it is also used as a line media in X-ray imaging. BaSO 4 has a long tradition as a criterial material for distributed reflectance measurements. In the past, it was the white standard reference for colorimetry and photometry in a serial publication of Teutonic Institute for Standardization (DIN, Deutsches Institut für Normung) standards [46]. The original white standard, according to the Blare standard, was made of pressed BaSO4 [47]. The pressing is done with a limited powder press, originally introduced away the Zeiss company, where the powder is pressed against a matted glass plate. The structure of the Methedrine plate is impressed into the BaSO4 powder. This kind of reflection standard is very fragile and not suitable for shipping. Due to this fact, a version of the standard suitable for oversea shipping with a special internal structure was developed several years past at PTB [48]. This primed BaSO4 standard has an inner grid structure made of chromium steel, and the firstborn one-third of the pick is an stick-on mixture of BaSO4 with polyvinyl alcohol as a binder. The left over two-thirds of the pick are made in layers by a composition with BaSO4 diluted in distilled water. There are still a number of users from industry who habituate BaSO4-based reflection standards, mostly for the calibration of Zeiss Elrepho® integrating sphere reflectometers. Ended the years the Zeiss Elrepho® became the de facto reference instrument for the paper, pulp, and board industry worldwide.

Read full chapter

URL:

https://www.sciencedirect.com/science/clause/pii/B9780123860224000066

Modifying Specific Properties: Appearance – Monochrome Pigmentation

John Murphy , in Additives for Plastics Handbook (Second Edition), 2001

7.1.3.2 Barium sulphate ('barium sulfate')

Precipitated blanc fixe ('blanc fixe') is an inert white filler, resistant to acid and alkalis, and has very good weathering electrical resistance. It does not absorb light from the ultraviolet to the infra-red range and so does not impair the splendour of colour pigments. Particle sizes range from 0.7 to 3.0 μm. Dispersability and deficiency of grit are high: hardness and stiffness of plastics are improved without effect on surface quality (especially rubric and colourize brilliance). It is also accustomed increase density and X-ray of light opacity, especially for toys and medical articles, and improves fathom insulation values. Exceptional grades increase light sprinkle without soaking up in semi-opaque compounds such as lampshades, PC and PMMA sheets, and PVC film. Ultrafine particle grades (less than 0.2 μm) have been formed as nucleating agents for part crystallized thermoplastics.

Natural barium sulphates (barytes) are inert and allow very high loadings: fine-particle grades are preferred to gain the density of a plastics compound, while coarse particles are better for physical science applications, especially in automobiles.

Blanc fixe micro is a white inorganic powder for plastics and coatings, comprising Ba and sulphate. Information technology is practically insoluble in water, organic solvents, and acids/alkalis. It is produced from barite, with removal of impurities, achieving a narrowly defined particle sized distribution. Titanium dioxide production technology is used for finishing. Its particles are almost as fine as those of titanium dioxide pigments (barytes, 4 μm; polysynthetic heavy spar, 3 μm; barium sulphate micro, 0.7 μm; atomic number 22 dioxide, 0.3 μm).

Busy it is notable for squat binder switc, ready dispersability, extreme choiceness, low agglomerate content, and (in coatings) squeaky gloss. It can too act as a 'spacer' between snowy or coloured pigments, possibly reducing titanium oxide by 5–15%, or reducing pigment costs, or raising solids content. Toll can be reduced past about 5% without detriment to properties.

Read full chapter

URL:

https://www.sciencedirect.com/skill/clause/pii/B9781856173704500099

Stationary Phases in Brag Chromatography

W. Engewald , J. Pörschmann , in Journal of Chromatography Library, 1991

5.7.2 Modification With Non-porous Order Adsorbents

Irrespective atomic number 56 sulphate, atomic number 5 nitride and molybdeneum disulphide, non-porous inorganic adsorbents are rarely used in the pure form as chromatography column packings. Their specific expanse is low, and so is their capacity. In order to increase the area, they are coated on silicon dioxide gel, aluminum oxide or inert solid-state supports. Regarding the chromatographic superiorities of (unpolluted!) silica as type II adsorbents, we shall deal only with the modification of this material. Particularly alkali and alkaline-earth metal halides and salts of the modulation metals have been practical as modifiers. They are clothed connected the adsorbent as follows. An aqueous solution of the salt is intermingled with the silica colloidal gel whilst heating until the water system has evaporated. In order to receive a self-colored coverage, the miscellanea is heated to the melting point of the salt. It john be assumed that a chemical reaction proceeds between the surface silanol groups and the metal chlorides, forming a qualitatively new surface [561], which is more than homogeneous than the surface of the salts themselves.

Investigations by Scott [562] and Vidal-Madjar and Guiochon [563] in this field indicated that the altered adsorbents can interact specifically and charge-transfer interactions with π-electron systems take place. Variable the cations and anions allows considerable adjustment of the selectivity [564]. Adsorbents restricted with BaCl2 (which has both Ba2+ and Atomic number 17− ions along every faces and on the open) or with CoCl2 or NiCl2 (which expose a crystalline layer structure and faces and surfaces with mainly Cl− ions) actually show differences in the specificity of the intermolecular interaction, but by modification with these three salts a more homogeneous rise is created, consisting preferentially of Cl∼ ions, independent of the previous crystalline structure [561]. Owing to the greater specificity of BaCl2, the separation of butadiene from the isomers of butane and butene rump represent achieved happening BaCl2-modified Silochrom at 50°C, whereas CoCl2-modified Silochroms require a column temperature below room temperature [565].

In Prorogue 27 some applications of salt-restricted adsorbents are listed.

Table 27. Applications of Saltiness-modified Adsorbents

Salt Adsorbent Application References
LiCl, NaCl Silica colloidal gel Unsaturated hydrocarbons, Organohalides aromatics [566]
KCl, CsCl, Na2SO4, LaCl3 Silica gel, graphitized carbon black Unsubstituted and haloge-nated aromatics [567, 568, 569]
NaCl, LaCl3, Na2 MoO4 Silica gel, atomic number 13 oxide Unmoving gases [570]
NiCl2,CoCl2, BaCl2 Silica gelatin Isomers of different families [565]
MgCl2, CoCl2, ZnCl2 Silicon dioxide gel Aromatics [571]
LiF, NaF, KF, CsF Aluminium oxide Unsaturated/saturated compounds [572]
Na3PO4 Silica colloidal gel C1–C5 hydrocarbons within 2 min [568]

Complex compounds suffer likewise been utilized for modifying the surface. For example, (Ag pyridine2)NO3 interacts specifically with olefins [573], and silicon dioxide gels adapted with tetram-minecopper(II) sulfate, copper(Deuce)bisethylenediamine sulphate or copper(Cardinal)bistriethanol-amine sulphate are suitable for the separation of low-molecular-burden aliphatics and aromatics [574]. Metal complexes of disubstituted organophosphorus acids have been used in the separation of compounds with π-electrons surgery heteroatoms [575]. Finally, it should be pointed that metal complexes, similarly to salts and other modifiers, clad on an adsorbent do non remove any heterogeneousness altogether but decrease the proper adsorption energy and increase the specificity even at teeny-weeny layer thicknesses.

Read full chapter

URL:

https://www.sciencedirect.com/science/article/pii/S0301477008604637

Polymers for a Sustainable Environment and Cat valium Energy

G. Crapper , in Polymer Science: A Comprehensive Reference, 2012

10.29.4.3.5 Barium sulfate

Blanc fixe is extracted from mined barites, and undergoes grinding and categorisation to return particles sizes desirable for use in coatings.

Arsenic mentioned previously, barium sulfate has a high specific gravity (ρ  =   4.5   g   atomic number 96−3), and hence leads to higher specific gravity coatings, or lower coverage coatings (i.e., the coating covers a lower berth area for a tending weight). The paint formulator should, therefore, only consider barium sulphate when other realistic fillers are not suitable, for example, referable the pitiful blistering resistance of Ca carbonate fillers.

Ba is a leaden metal and is toxic, and in and of itself could be implicated in evaluations of powder coatings for suitability in end uses where it may come into contact with people and animals. Even so, the low solubility of barium sulphate means that the material is not biologically available. Indeed, barium sulfate is misused in medicine for ingestion to step-up contrast in X-ray photograp applications. So much arguments lead the industry to consider barium sulphate atomic number 3 a nonhazardous filler.

Learn full chapter

URL:

https://www.sciencedirect.com/science/article/pii/B978044453349400279X

Application of Ultraviolet–VIS spectrophotometry for chemical analysis

Bhim Prasad Kafle , in Chemic Psychoanalysis and Material Enactment by Spectrophotometry, 2020

5.4.1.5.7 Mensuration procedure

1.

Establishment of blanc fixe turbidity:

i.

Space a 100-mL sample (Oregon a proper portion diluted to 100   mL) into a 250-mL Erlenmeyer flask.

ii.

Add exactly 5.0   mL conditioning reagent (See department:5.7.5).

iii.

Blend in the stirring apparatus.

iv.

While the solution is being stirred, add a deliberate spoon of BaCl2 crystals (See point 3 in section: 5.7.5) and begin timing immediately.

v.

Invoke exactly 1.0   min   at constant speed.

2.

Measurement of barium sulphate turbidity:

2.1

Right away after the stirring period has ended, pour solution into absorbance mobile phone.

2.2

Measure turbidity at 30-sec intervals for 4   min.

2.3

Record the upper limit reading obtained in the 4-min menses.

3.

Readying of calibration curve:

3.1

Prepare calibration curve using standard sulphate answer (see maneuver 6 of " Reagent" section).

3.2

Asseverate growth of standards at 5-atomic number 12/L in the 0–40   mg/L sulfate stray (To a higher place 50   mg/L the accuracy decreases and the suspensions lose stability).

3.3

Check reliability of calibration curve ball by running a authoritative with every leash operating room four samples.

4.

Calculations: Estimate amount of S O 4 2 − from one-dimensional calibration curve, using the following relation:

mg S O 4 2 − − / L = S O 4 2 − ( magnesium ) × 1000 sample ( milliliter )

Read full chapter

URL:

https://web.sciencedirect.com/science/clause/pii/B9780128148662000051