Aluminium hydroxide

Aluminium hydroxide, Al(OH)3, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is amphoteric in nature, i.e., it has both basic and acidic properties. Closely related are aluminium oxide hydroxide, AlO(OH), and aluminium oxide or alumina (Al2O3), the latter of which is also amphoteric. These compounds together are the major components of the aluminium ore bauxite.

Aluminium hydroxide
Unit cell ball and stick model of aluminium hydroxide
Sample of aluminium hydroxide in a vial
Names
Preferred IUPAC name
Aluminium hydroxide
Systematic IUPAC name
Aluminium(3+) trioxidanide
Other names
Aluminic acid

Aluminic hydroxide
Aluminium(III) hydroxide
Aluminium hydroxide
Aluminum trihydroxide
Hydrated alumina

Orthoaluminic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.040.433
KEGG
RTECS number BD0940000
UNII
Properties[1][2]
Al(OH)3
Molar mass 78.00 g/mol
Appearance White amorphous powder
Density 2.42 g/cm3, solid
Melting point 300 °C (572 °F; 573 K)
0.0001 g/100 mL
3×10−34
Solubility soluble in acids and alkalis
Acidity (pKa) >7
Isoelectric point 7.7
Thermochemistry[3]
−1277 kJ·mol−1
Pharmacology[4]
A02AB01 (WHO)
  • US: B (No risk in non-human studies)
Hazards
Safety data sheet External MSDS
GHS pictograms GHS-pictogram-exclam
H319, H335
P264, P261, P280, P271, P312, P304+340, P305+351+338, P337+313
NFPA 704
Flammability code 0: Will not burn. E.g., waterHealth code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentineReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
0
1
0
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
>5000 mg/kg (rat, oral)
Related compounds
Other anions
None
Related compounds
Sodium oxide,
aluminium oxide hydroxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Nomenclature

The naming for the different forms of aluminium hydroxide is ambiguous and there is no universal standard. All four polymorphs have a chemical composition of aluminium trihydroxide (one aluminium atom attached to three hydroxide groups).[5]

Gibbsite is also known as hydrargillite, named after the Greek words for water (hydra) and clay (argylles). The first compound named hydrargillite was thought to be aluminium hydroxide, but was later found to be aluminium phosphate; despite this, both gibbsite and hydrargillite are used to refer to the same polymorphism of aluminium hydroxide, with gibbsite used most commonly in the United States and hydrargillite used more often in Europe. In 1930, it was referred to as α-alumina trihydrate to contrast it with bayerite, which was called β-alumina trihydrate (the alpha and beta designations were used to differentiate the more- and less-common forms respectively). In 1957, a symposium on alumina nomenclature attempted to develop a universal standard, resulting in gibbsite being designated γ-Al(OH)3, bayerite becoming α-Al(OH)3, and nordstrandite being designated Al(OH)3. Based on their crystallographic properties, a suggested nomenclature and designation is for gibbsite to be α-Al(OH)3, bayerite to be designated β-Al(OH)3, and both nordstrandite and doyleite are designated Al(OH)3. Under this designation, the α and β prefixes refer to hexagonal, close-packed structures and altered or dehydrated polymorphisms respectively, with no differentiation between nordstrandite and doyleite.[5]

Properties

Gibbsite has a typical metal hydroxide structure with hydrogen bonds. It is built up of double layers of hydroxyl groups with aluminium ions occupying two-thirds of the octahedral holes between the two layers.[6][7]

Aluminium hydroxide is amphoteric. In acid, it acts as a Brønsted-Lowry base by picking up hydrogen ions and neutralizes the acid, yielding a salt:[8]

3HCl + Al(OH)3 → AlCl3 + 3H2O

In bases, it acts a Lewis acid by taking an electron pair from the hydroxide ions:[8]

Al(OH)3 + OH → Al(OH)4

Polymorphism

Four polymorphs of aluminium hydroxide exist, all based on the common combination of one aluminium atom and three hydroxide molecules into different crystalline arrangements that determine the appearance and properties of the compound. The four combinations are:[5]

All polymorphs are composed of layers of octahedral aluminium hydroxide units with the aluminium atom in the centre and the hydroxyl groups on the sides, with hydrogen bonds holding the layers together. The polymorphisms vary in how the layers stack together, with the arrangements of the molecules and layers determined by the acidity, presence of ions (including salt) and the surface of the minerals the substance forms on. Under most conditions, gibbsite is the most chemically stable form of aluminium hydroxide. All forms of Al(OH)3 crystals are hexagonal.[5]

Production

Virtually all the aluminium hydroxide used commercially is manufactured by the Bayer process[9] which involves dissolving bauxite in sodium hydroxide at temperatures up to 270 °C (518 °F). The waste solid, bauxite tailings, is removed and aluminium hydroxide is precipitated from the remaining solution of sodium aluminate. This aluminium hydroxide can be converted to aluminium oxide or alumina by calcination.

The residue or bauxite tailings, which is mostly iron oxide, is highly caustic due to residual sodium hydroxide. It was historically stored in lagoons; this led to the Ajka alumina plant accident in 2010 in Hungary, where a dam bursting led to the drowning of nine people. An additional 122 sought treatment for chemical burns. The mud contaminated 40 square kilometres (15 sq mi) of land and reached the Danube. While the mud was considered non-toxic due to low levels of heavy metals, the associated slurry had pH of 13.[10]

Uses

One of the major uses of aluminium hydroxide is as a feedstock for the manufacture of other aluminium compounds: speciality calcined aluminas, aluminium sulfate, polyaluminium chloride, aluminium chloride, zeolites, sodium aluminate, activated alumina, and aluminium nitrate.[7]

Freshly precipitated aluminium hydroxide forms gels, which are the basis for the application of aluminium salts as flocculants in water purification. This gel crystallizes with time. Aluminium hydroxide gels can be dehydrated (e.g. using water-miscible non-aqueous solvents like ethanol) to form an amorphous aluminium hydroxide powder, which is readily soluble in acids. Aluminium hydroxide powder which has been heated to an elevated temperature under carefully controlled conditions is known as activated alumina and is used as a desiccant, as an adsorbent in gas purification, as a Claus catalyst support for water purification, and as an adsorbent for the catalyst during the manufacture of polyethylene by the Sclairtech process.

Fire retardant

Aluminium hydroxide also finds use as a fire retardant filler for polymer applications in a similar way to magnesium hydroxide and mixtures of huntite and hydromagnesite.[11][12][13][14][15] It decomposes at about 180 °C (356 °F), absorbing a considerable amount of heat in the process and giving off water vapour. In addition to behaving as a fire retardant, it is very effective as a smoke suppressant in a wide range of polymers, most especially in polyesters, acrylics, ethylene vinyl acetate, epoxies, PVC and rubber.[16]

Pharmaceutical

Under the generic name "algeldrate", aluminium hydroxide is used as an antacid in humans and animals (mainly cats and dogs). It is preferred over other alternatives such as sodium bicarbonate because Al(OH)3, being insoluble, does not increase the pH of stomach above 7 and hence, does not trigger secretion of excess acid by the stomach. Brand names include Alu-Cap, Aludrox, Gaviscon or Pepsamar. It reacts with excess acid in the stomach, reducing the acidity of the stomach content,[17][18] which may relieve the symptoms of ulcers, heartburn or dyspepsia. Such products can cause constipation, because the aluminium ions inhibit the contractions of smooth muscle cells in the gastrointestinal tract, slowing peristalsis and lengthening the time needed for stool to pass through the colon.[19] Some such products (such as Maalox) are formulated to minimize such effects through the inclusion of equal concentrations of magnesium hydroxide or magnesium carbonate, which have counterbalancing laxative effects.[20]

This compound is also used to control hyperphosphatemia (elevated phosphate, or phosphorus, levels in the blood) in people and animals suffering from kidney failure. Normally, the kidneys filter excess phosphate out from the blood, but kidney failure can cause phosphate to accumulate. The aluminium salt, when ingested, binds to phosphate in the intestines and reduce the amount of phosphorus that can be absorbed.[21][22]

Precipitated aluminium hydroxide is included as an adjuvant in some vaccines (e.g. anthrax vaccine). One of the well-known brands of aluminium hydroxide adjuvant is Alhydrogel, made by Brenntag Biosector.[23] Since it absorbs protein well, it also functions to stabilize vaccines by preventing the proteins in the vaccine from precipitating or sticking to the walls of the container during storage. Aluminium hydroxide is sometimes called "alum", a term generally reserved for one of several sulfates.

Vaccine formulations containing aluminium hydroxide stimulate the immune system by inducing the release of uric acid, an immunological danger signal. This strongly attracts certain types of monocytes which differentiate into dendritic cells. The dendritic cells pick up the antigen, carry it to lymph nodes, and stimulate T cells and B cells.[24] It appears to contribute to induction of a good Th2 response, so is useful for immunizing against pathogens that are blocked by antibodies. However, it has little capacity to stimulate cellular (Th1) immune responses, important for protection against many pathogens,[25] nor is it useful when the antigen is peptide-based.[26]

Potential adverse effects

In the 1960s and 1970s it was speculated that aluminium was related to various neurological disorders, including Alzheimer's disease.[27][28] Since then, multiple epidemiological studies have found no connection between exposure to aluminium and neurological disorders.[29][30][31]

References

  1. ^ For solubility product: "Archived copy". Archived from the original on 15 June 2012. Retrieved 2012-05-17.CS1 maint: Archived copy as title (link)
  2. ^ For isoelectric point: Gayer, K. H.; Thompson, L. C.; Zajicek, O. T. (September 1958). "The solubility of aluminum hydroxide in acidic and basic media at 25 ?c". Canadian Journal of Chemistry. 36 (9): 1268–1271. doi:10.1139/v58-184. ISSN 0008-4042.
  3. ^ Zumdahl, Steven S. (2009). Chemical Principles (6th ed.). Houghton Mifflin Company. ISBN 978-0-618-94690-7.
  4. ^ Black, Ronald A.; Hill, D. Ashley (2003-06-15). "Over-the-Counter Medications in Pregnancy". American Family Physician. 67 (12): 2517–2524. ISSN 0002-838X. Retrieved 2017-07-01.
  5. ^ a b c d Karamalidis, AK; Dzombak DA (2010). Surface Complexation Modeling: Gibbsite. John Wiley & Sons. pp. 15–17. ISBN 978-0-470-58768-3.
  6. ^ Wells, A.F. (1975), Structural Inorganic Chemistry (4th ed.), Oxford: Clarendon Press
  7. ^ a b Evans, KA (1993). "Properties and uses of aluminium oxides and aluminium hydroxides". In A. J. Downs. Chemistry of aluminium, gallium, indium, and thallium (1st ed.). London; New York: Blackie Academic & Professional. ISBN 9780751401035.
  8. ^ a b Boundless (2016-07-26). "Basic and Amphoteric Hydroxides". Boundless Chemistry. Retrieved 2017-07-02.
  9. ^ Hind, AR; Bhargava SK; Grocott SC (1999). "The Surface Chemistry of Bayer Process Solids: A Review". Colloids Surf Physiochem Eng Aspects. 146 (1–3): 359–74. doi:10.1016/S0927-7757(98)00798-5.
  10. ^ "Hungary Battles to Stem Torrent of Toxic Sludge". BBC News Website. 5 October 2010.
  11. ^ Hollingbery, LA; Hull TR (2010). "The Fire Retardant Behaviour of Huntite and Hydromagnesite - A Review" (PDF). Polymer Degradation and Stability. 95 (12): 2213–2225. doi:10.1016/j.polymdegradstab.2010.08.019.
  12. ^ Hollingbery, LA; Hull TR (2010). "The Thermal Decomposition of Huntite and Hydromagnesite - A Review" (PDF). Thermochimica Acta. 509 (1–2): 1–11. doi:10.1016/j.tca.2010.06.012.
  13. ^ Hollingbery, LA; Hull TR (2012). "The Fire Retardant Effects of Huntite in Natural Mixtures with Hydromagnesite" (PDF). Polymer Degradation and Stability. 97 (4): 504–512. doi:10.1016/j.polymdegradstab.2012.01.024.
  14. ^ Hollingbery, LA; Hull TR (2012). "The Thermal Decomposition of Natural Mixtures of Huntite and Hydromagnesite" (PDF). Thermochimica Acta. 528: 45–52. doi:10.1016/j.tca.2011.11.002.
  15. ^ Hull, TR; Witkowski A; Hollingbery LA (2011). "Fire Retardant Action of Mineral Fillers" (PDF). Polymer Degradation and Stability. 96 (8): 1462–1469. doi:10.1016/j.polymdegradstab.2011.05.006.
  16. ^ Huber Engineered Materials. "Huber Non-Halogen Fire Retardant Additives" (PDF). Retrieved 2017-07-03.
  17. ^ Galbraith, A; Bullock, S; Manias, E; Hunt, B; Richards, A (1999). Fundamentals of pharmacology: a text for nurses and health professionals. Harlow: Pearson. p. 482.
  18. ^ Papich, Mark G. (2007). "Aluminum Hydroxide and Aluminum Carbonate". Saunders Handbook of Veterinary Drugs (2nd ed.). St. Louis, Mo: Saunders/Elsevier. pp. 15–16. ISBN 9781416028888.
  19. ^ Washington, Neena (2 August 1991). Antacids and Anti Reflux Agents. Boca Raton, FL: CRC Press. p. 10. ISBN 978-0-8493-5444-1.
  20. ^ Bill, Robert L. (2016-09-01). Clinical Pharmacology and Therapeutics for Veterinary Technicians - E-Book. Elsevier Health Sciences. p. 105. ISBN 9780323444026.
  21. ^ Plumb, Donald C. (2011). "Aluminum Hydroxide". Plumb's Veterinary Drug Handbook (7th ed.). Stockholm, Wisconsin; Ames, Iowa: Wiley. pp. 36–37. ISBN 9780470959640.
  22. ^ Lifelearn Inc. (2010-11-01). "Aluminum Hydroxide". Know Your Pet. Retrieved 2017-06-30.
  23. ^ "About Brenntag Biosector - Brenntag". www.brenntag.com. Retrieved 19 April 2018.
  24. ^ Kool, M; Soullié T; van Nimwegen M; Willart MA; Muskens F; Jung S; Hoogsteden HC; Hammad H; Lambrecht BN (2008-03-24). "Alum adjuvant boosts adaptive immunity by inducing uric acid and activating inflammatory dendritic cells". J Exp Med. 205 (4): 869–82. doi:10.1084/jem.20071087. PMC 2807488. PMID 18362170.
  25. ^ Petrovsky N, Aguilar JC (2004). "Vaccine adjuvants: current state and future trends". Immunol Cell Biol. 82 (5): 488–96. doi:10.1111/j.0818-9641.2004.01272.x. PMID 15479434.
  26. ^ Cranage, MP; Robinson A (2003). Robinson A; Hudson MJ; Cranage MP, eds. Vaccine Protocols - Volume 87 of Methods in Molecular Medicine Biomed Protocols (2nd ed.). Springer. p. 176. ISBN 978-1-59259-399-6.
  27. ^ "Alzheimer's Myth's". Alzheimer's Association. Retrieved 2012-07-29.
  28. ^ Khan, A (1 September 2008). "Aluminium and Alzheimer's disease". Alzheimer's Society. Archived from the original on 11 March 2012. Retrieved 8 March 2012.
  29. ^ Rondeau V (2002). "A review of epidemiologic studies on aluminum and silica in relation to Alzheimer's disease and associated disorders". Rev Environ Health. 17 (2): 107–21. doi:10.1515/REVEH.2002.17.2.107. PMC 4764671. PMID 12222737.
  30. ^ Martyn CN, Coggon DN, Inskip H, Lacey RF, Young WF (May 1997). "Aluminum concentrations in drinking water and risk of Alzheimer's disease". Epidemiology. 8 (3): 281–6. doi:10.1097/00001648-199705000-00009. JSTOR 3702254. PMID 9115023.
  31. ^ Graves AB, Rosner D, Echeverria D, Mortimer JA, Larson EB (September 1998). "Occupational exposures to solvents and aluminium and estimated risk of Alzheimer's disease". Occup Environ Med. 55 (9): 627–33. doi:10.1136/oem.55.9.627. PMC 1757634. PMID 9861186.

External links

ATH

Ath is a city in Belgium.

The acronym ATH may also refer to:

The IATA airport code for Athens International Airport in Athens, Greece

The National Rail code for Atherstone railway station, United Kingdom

Around the Horn, an ESPN Television Show

ATH, an abbreviation for atherosclerosis

the absolute threshold of hearing, a phenomenon of psychoacoustics

ATH, Polish abbreviation for University of Bielsko-Biała (Akademia Techniczno-Humanistyczna w Bielsku-Białej)

ATH (interbank network), an interbank network in Puerto Rico and the Caribbean

A Toda Hora, a Colombian interbank network

ATH, the command to "hang up" in the Hayes command set

ATH, an abbreviation, standing for "athlete" used in American football recruiting to denote a recruit whose position on the team has not yet been determined

Alton Towers Hotel

ATH is a common name for Alumina Trihydrate, see Aluminium hydroxide

Activated alumina

Activated alumina is manufactured from aluminium hydroxide by dehydroxylating it in a way that produces a highly porous material; this material can have a surface area significantly over 200 m²/g. The compound is used as a desiccant (to keep things dry by absorbing water from the air) and as a filter of fluoride, arsenic and selenium in drinking water. It is made of aluminium oxide (alumina; Al2O3). It has a very high surface-area-to-weight ratio, due to the many "tunnel like" pores that it has. Activated alumina in its phase composition can be represented only by metastable forms (gamma-Al2O3 etc.). Corundum (alpha-Al2O3), the only stable form of aluminum oxide, does not have such a chemically active surface and is not used as a sorbent.

Adjuvant

An adjuvant is a pharmacological or immunological agent that modifies the effect of other agents. Adjuvants may be added to a vaccine to boost the immune response to produce more antibodies and longer-lasting immunity, thus minimizing the dose of antigen needed. Adjuvants may also be used to enhance the efficacy of a vaccine by helping to modify the immune response to particular types of immune system cells: for example, by activating T cells instead of antibody-secreting B cells depending on the purpose of the vaccine. Adjuvants are also used in the production of antibodies from immunized animals. There are different classes of adjuvants that can push immune response in different directions, but the most commonly used adjuvants include aluminum hydroxide and paraffin oil.

Aloxiprin

Aloxiprin (or aluminium acetylsalicylate) is a medical drug used for the treatment of pain and inflammation associated with muscular skeletal and joint disorders.

It is used for its properties as an anti-inflammatory, antipyretic and analgesic drug.

It is a chemical compound of aluminium hydroxide and aspirin.

Alum

An alum () is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula XAl(SO4)2·12H2O, where X is a monovalent cation such as potassium or ammonium. By itself, "alum" often refers to potassium alum, with the formula KAl(SO4)2·12H2O. Other alums are named after the monovalent ion, such as sodium alum and ammonium alum.

The name "alum" is also used, more generally, for salts with the same formula and structure, except that aluminium is replaced by another trivalent metal ion like chromium(III), and/or sulfur is replaced by other chalcogen like selenium. The most common of these analogs is chrome alum KCr(SO4)2·12H2O.

In some industries, the name "alum" (or "papermaker's alum") is used to refer to aluminium sulfate Al2(SO4)3·nH2O. Most industrial flocculation done with "alum" actually uses aluminium sulfate. In medicine, "alum" may also refer to aluminium hydroxide gel used as a vaccine adjuvant.

Aluminium carbonate

Aluminium carbonate (Al2(CO3)3), is a carbonate of aluminium. It is not well characterized; one authority says that simple carbonates of aluminium, gallium and indium are not known. Basic sodium aluminium carbonate, the mineral dawsonite, is a known compound.

Aluminium chloride

Aluminium chloride (AlCl3), also known as aluminium trichloride, is the main compound of aluminium and chlorine. It is white, but samples are often contaminated with iron(III) chloride, giving it a yellow color. The solid has a low melting and boiling point. It is mainly produced and consumed in the production of aluminium metal, but large amounts are also used in other areas of the chemical industry. The compound is often cited as a Lewis acid. It is an example of an inorganic compound that reversibly changes from a polymer to a monomer at mild temperature.

Aluminium hydroxide oxide

Aluminium hydroxide oxide or aluminium oxyhydroxide, AlO(OH) is found as one of two well defined crystalline phases, which are also known as the minerals boehmite and diaspore. The minerals are important constituents of the aluminium ore, bauxite.

Antacid

An antacid is a substance which neutralizes stomach acidity and is used to relieve heartburn, indigestion or an upset stomach.

Bauxite

Bauxite is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium. Bauxite consists mostly of the aluminium minerals gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(OH)), mixed with the two iron oxides goethite and haematite, the aluminium clay mineral kaolinite and small amounts of anatase (TiO2) and ilmenite (FeTiO3 or FeO.TiO2).In 1821 the French geologist Pierre Berthier discovered bauxite near the village of Les Baux in Provence, southern France.

Bayer process

The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide). Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al2O3), the rest being a mixture of silica, various iron oxides, and titanium dioxide. The aluminium oxide must be purified before it can be refined to aluminium metal.

Blue Pond (Biei)

Blue Pond (青い池, Aoi-ike) is a man-made pond feature in Biei, Hokkaido, Japan. It is the result of works on the Biei River (美瑛川), carried out after the 1988 eruption of Mount Tokachi, to protect the town of Biei from volcanic mudflows. The colour is thought to result from the accidental presence of colloidal aluminium hydroxide in the water. Damage caused by Typhoon Mindulle in August 2016 resulted in a temporary drop in the water level and in the colour briefly turning brown with mud and sand from the Biei River.

Carl Josef Bayer

Carl Josef Bayer (also Karl Bayer, March 4, 1847 – October 4, 1904) was an Austrian chemist who invented the Bayer process of extracting alumina from bauxite, essential to this day to the economical production of aluminium.

Bayer had been working in Saint Petersburg to develop a method to provide alumina to the textile industry that used it as a fixing agent in the dyeing of cotton. In 1887, he discovered that aluminium hydroxide precipitated from an alkaline solution which is crystalline and can be filtered and washed more easily than that precipitated from an acid medium by neutralization. In 1888, Bayer developed and patented his four-stage process of extracting alumina from bauxite ore.

In the mid-19th-century, aluminium was so precious that a bar of the metal was exhibited alongside the French Crown Jewels at the Exposition Universelle in Paris 1855. Along with the Hall-Héroult process, Bayer's solution caused the price of aluminum to drop about 80% in 1890 from what it had been in 1854.

Cytoprotection

Cytoprotection is a process by which chemical compounds provide protection to cells against harmful agents.For example, a gastric cytoprotectant is any medication that combats ulcers not by reducing gastric acid but by increasing mucosal protection. Examples of gastric cytoprotective agents include prostaglandins which protect the stomach mucosa against injury by increasing gastric mucus secretion. Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit the synthesis of prostaglandins and thereby make the stomach more susceptible to injury. Gastric cytoprotective drugs include carbenoxolone, deglycyrrhizinised liquorice, sucralfate (aluminium hydroxide and sulphated sucrose), misoprostol (a prostaglandin analogue), bismuth chelate (tri-potassium di-citrato bismuthate) and zinc L-carnosine.

Deville process

The Deville process was the first industrial process used to produce alumina from bauxite.

The Frenchman Henri Sainte-Claire Deville invented the process in 1859. It is sometimes called the Deville-Pechiney process.

It is based on the extraction of alumina with sodium carbonate.

The first stage is the calcination of the bauxite at 1200 °C with sodium carbonate and coke. The alumina is converted in sodium aluminate. Iron oxide remains unchanged and silica forms a polysilicate.

In the second stage sodium hydroxide solution is added, which dissolves the sodium aluminate, leaving the impurities as a solid residue. The amount of sodium hydroxide solution needed depends upon the amount of silica present in the raw material. The solution is filtered off; carbon dioxide is bubbled through the solution, causing aluminium hydroxide to precipitate, leaving a solution of sodium carbonate. The latter can be recovered and reused in the first stage.

The aluminium hydroxide is calcined to produce alumina.

The process was used in France at Salindres until 1923 and in Germany and Great Britain until the outbreak of the Second World War.It has now been replaced by the Bayer process.

Euclase

Euclase is a beryllium aluminium hydroxide silicate mineral (BeAlSiO4(OH)). It crystallizes in the monoclinic crystal system and is typically massive to fibrous as well as in slender prismatic crystals. It is related to beryl (Be3Al2Si6O18) and other beryllium minerals. It is a product of the decomposition of beryl in pegmatites.Euclase crystals are noted for their blue color, ranging from very pale to dark blue. The mineral may also be colorless, white, or light green. Cleavage is perfect, parallel to the clinopinacoid, and this suggested to René Just Haüy the name euclase, from the Greek εὖ, easily, and κλάσις, fracture. The ready cleavage renders the crystals fragile with a tendency to chip, and thus detracts from its use for personal ornament. When cut it resembles certain kinds of beryl and topaz, from which it may be distinguished by its specific gravity (3.1). Its hardness (7.5) is similar to beryl (7.5 - 8), and a bit less than that of topaz (8).

It was first reported in 1792 from the Orenburg district in the southern Urals, Russia, where it is found with topaz and chrysoberyl in the gold-bearing gravels of the Sanarka (nowadays probably, Sakmara River, Mednogorsk district, Orenburgskaya Oblast'). Its type locality is Ouro Prêto, Minas Gerais, Southeast Region, Brazil, where it occurs with topaz. It is found rarely in the mica-schist of the Rauris in the Austrian Alps.

Gibbsite

Gibbsite, Al(OH)3, is one of the mineral forms of aluminium hydroxide. It is often designated as γ-Al(OH)3 (but sometimes as α-Al(OH)3.). It is also sometimes called hydrargillite (or hydrargyllite).

Gibbsite is an important ore of aluminium in that it is one of three main phases that make up the rock bauxite.

Gibbsite has three named structural polymorphs or polytypes: bayerite (designated often as α-Al(OH)3, but sometimes as β-Al(OH)3), doyleite, and nordstrandite. Gibbsite and bayerite are monoclinic, whereas doyleite and nordstrandite are triclinic forms.

Maalox

Maalox was a brand of antacid owned by Sanofi. Their main product was a flavored liquid containing aluminium hydroxide and magnesium hydroxide, which acts to neutralize or reduce stomach acid, for the purpose of relieving the symptoms of indigestion, heartburn, gastroesophageal reflux disease, and also stomach or duodenal ulcers. In large doses, it can act as a laxative. The trademark is owned by Novartis International AG, and was first produced commercially in 1949.

Anachronistically, ‘MAALOX’ is an abbreviation of compositional elements MAgnesium, and ALuminium, as OXides of hydrogen, in an anionic, aqueous hydroxide solution. This reacts with cationic, aqueous hydrochloride found in the gut, resulting in ion-exchange neutralisation of the acid base into water and/or salt.

Some may find certain Maalox medications, such as Maalox Multi-Action, to be a successful anti-diarrhea treatment due to the aluminium hydroxide content, which in normal situations has a tendency to result in constipation. Maalox may also be used to treat nausea and stomach cramps associated with dyspepsia, diarrhea, or constipation.

Sodium aluminate

Sodium aluminate is an inorganic chemical that is used as an effective source of aluminium hydroxide for many industrial and technical applications. Pure sodium aluminate (anhydrous) is a white crystalline solid having a formula variously given as NaAlO2, NaAl(OH)4 (hydrated), Na2O·Al2O3, or Na2Al2O4. Commercial sodium aluminate is available as a solution or a solid.

Other related compounds, sometimes called sodium aluminate, prepared by reaction of Na2O and Al2O3 are Na5AlO4 which contains discrete AlO45− anions, Na7Al3O8 and Na17Al5O16 which contain complex polymeric anions, and NaAl11O17, once mistakenly believed to be β-alumina, a phase of aluminium oxide.

Aluminium compounds
Al(I)
Al(II)
Al(III)
Magnesium (increases motility)
Aluminium (decreases motility)
Calcium
Sodium
Combinations and complexes
of aluminium, calcium and magnesium
Drugs for treatment of hyperkalemia and hyperphosphatemia (V03AE)
Potassium binders
Phosphate binders
Molecules
Deuterated
molecules
Unconfirmed
Related

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