Aluminium phosphate
Encyclopedia
Aluminium phosphate is a chemical compound
. It is used in cake mixes and in some baking powder
s as a leavening agent to help baked goods rise. Medicinally it is used as adsorbent for toxoid.
and phosphorus pentoxide
, the latter of which is very effective at absorbing water. Phosphorus pentoxide may be useful in a number of applications including the production of ketene
from acetic acid
, although this process is rather dangerous and may yield a significant amount of byproducts.
and Southern Africa
, alumiunium phosphate is generally the most common form of phosphorus in soil
s, as it forms when phosphate in rainwater reacts with dissolved aluminium in the soil. Although it is not as insoluble as many other components of soils in those regions, aluminium phosphate can form exceedingly insoluble double salt
s known as taranakite
s with many essential elements for plant growth that are normally highly soluble in water, such as potassium
and nitrogen
.
In coastal areas of South Africa
and Namibia
, the combination of exceedingly old soils and a high input of phosphate from very fertile oceans due to the Benguela Current
causes aluminium phosphate to accumulate to form a concentrated mineral, known as aluminium phosphate rock. Only in recent years has there been any interest in the mining of these considerable deposits as a source of phosphorus for agriculture
, but there could be considerable economic value if low-cost treatment becomes possible.
The mineral form of aluminium phosphate, berlinite
, is rarely found in the nature. It possess quartz-like structure, which makes these 2 minerals often hard to distinguish by standard laboratory methods (like Powder X-Ray Diffraction)
Chemical compound
A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
. It is used in cake mixes and in some baking powder
Baking powder
Baking powder is a dry chemical leavening agent used to increase the volume and lighten the texture of baked goods such as muffins, cakes, scones and American-style biscuits. Baking powder works by releasing carbon dioxide gas into a batter or dough through an acid-base reaction, causing bubbles in...
s as a leavening agent to help baked goods rise. Medicinally it is used as adsorbent for toxoid.
Uses
Aluminium phosphate is used industrially as a high-temperature dehydrating agent. When heated to decomposition, aluminium phosphate decomposes into aluminium oxideAluminium oxide
Aluminium oxide is an amphoteric oxide with the chemical formula 23. It is commonly referred to as alumina, or corundum in its crystalline form, as well as many other names, reflecting its widespread occurrence in nature and industry...
and phosphorus pentoxide
Phosphorus pentoxide
Phosphorus pentoxide is a chemical compound with molecular formula P4O10 . This white crystalline solid is the anhydride of phosphoric acid. It is a powerful desiccant.-Structure:...
, the latter of which is very effective at absorbing water. Phosphorus pentoxide may be useful in a number of applications including the production of ketene
Ketene
A ketene is an organic compound of the form R'RC=C=O. The term is also used specifically to mean ethenone, the simplest ketene, where R' and R are hydrogen atoms.Ketenes were first studied as a class by Hermann Staudinger.-Formation:...
from acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...
, although this process is rather dangerous and may yield a significant amount of byproducts.
- 4AlPO4 → 2Al2O3 + P4O10
- -
- 6CH3COOH + P4O10 → 4H3PO4 + 6CH2COKeteneA ketene is an organic compound of the form R'RC=C=O. The term is also used specifically to mean ethenone, the simplest ketene, where R' and R are hydrogen atoms.Ketenes were first studied as a class by Hermann Staudinger.-Formation:...
- CH2CO + CH3COOH → (CH3CO)2OAcetic anhydrideAcetic anhydride, or ethanoic anhydride, is the chemical compound with the formula 2O. Commonly abbreviated Ac2O, it is the simplest isolatable acid anhydride and is a widely used reagent in organic synthesis...
Occurrence
Although it is unstable to heat, in geologically stable regions like AustraliaAustralia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and Southern Africa
Southern Africa
Southern Africa is the southernmost region of the African continent, variably defined by geography or geopolitics. Within the region are numerous territories, including the Republic of South Africa ; nowadays, the simpler term South Africa is generally reserved for the country in English.-UN...
, alumiunium phosphate is generally the most common form of phosphorus in soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
s, as it forms when phosphate in rainwater reacts with dissolved aluminium in the soil. Although it is not as insoluble as many other components of soils in those regions, aluminium phosphate can form exceedingly insoluble double salt
Double salt
Double salts are salts containing more than one cation or anion. They form when more than one salt is dissolved in a liquid and when together they crystallize in a regular pattern. A well-known double salt is alum containing two cations and a sulfate anion...
s known as taranakite
Taranakite
Taranakite is a hydrated alkali iron-aluminium phosphate mineral with chemical formula 3526·18H2O. It forms from the reaction of clay minerals or aluminous rocks with solutions enriched in phosphate derived from bat or bird guano or, less commonly, from bones or other organic matter...
s with many essential elements for plant growth that are normally highly soluble in water, such as potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
and nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...
.
In coastal areas of South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...
and Namibia
Namibia
Namibia, officially the Republic of Namibia , is a country in southern Africa whose western border is the Atlantic Ocean. It shares land borders with Angola and Zambia to the north, Botswana to the east and South Africa to the south and east. It gained independence from South Africa on 21 March...
, the combination of exceedingly old soils and a high input of phosphate from very fertile oceans due to the Benguela Current
Benguela Current
The Benguela Current is the broad, northward flowing ocean current that forms the eastern portion of the South Atlantic Ocean gyre. The current extends from roughly Cape Point in the south, to the position of the Angola-Benguela Front in the north, at around 16°S. The current is driven by the...
causes aluminium phosphate to accumulate to form a concentrated mineral, known as aluminium phosphate rock. Only in recent years has there been any interest in the mining of these considerable deposits as a source of phosphorus for agriculture
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
, but there could be considerable economic value if low-cost treatment becomes possible.
The mineral form of aluminium phosphate, berlinite
Berlinite
Berlinite is a rare phosphate mineral. It has the same crystal structure as quartz with a low temperature polytype isostructural with α–quartz and a high temperature polytype isostructural with β–quartz...
, is rarely found in the nature. It possess quartz-like structure, which makes these 2 minerals often hard to distinguish by standard laboratory methods (like Powder X-Ray Diffraction)