Potassium alum , alumumumumum , or potassium aluminum sulfate are chemical compounds: double sulfate of potassium and aluminum, under the chemical formula KAl (SO 4 ) 2 . It is usually encountered as a dodecahydrate, KAl (SO 4 ) 2 O. It crystallizes in a cubic structure with a group of spaces P a -3 and lattice parameters 12,18 ÃÆ'â € |. This compound is the most important member of the generic class of compounds called alum, and is often referred to as alum .
Potassium alum is commonly used in water purification, leather tanning, dyeing, flame retardant textile, and baking powder. It also has cosmetic uses as a deodorant, as aftershave treatment and as a blood-restriction medication for minor bleeding from shaving.
Video Potassium alum
History
In Antiquity
Tawas potas are known to the Ancient Egyptians, who obtained them from evaporites in the Western desert and reportedly used them in the early 1500 BC to reduce visible turbidity (turbidity) in the water.
Potassium alum is described by the name Pliny's aloud or salsugoterrae , and it is clearly the same as stupteria described by Dioscorides. However, the name alum and other names applied to this substance - such as misy , sory , chalcanthum , and atramentum sutorium - often applied to other products with somewhat similar properties or uses, such as iron sulphate or "green vitriol".
The production of potassium alum from alunite is archaeologically proven on the island of Lesbos. The site was abandoned in the 7th century but dates back at least to the 2nd century.
Tawas potassium is mentioned in Ayurveda under the name phitkari or saurashtri . It is used in traditional Chinese medicine under the name In the Middle Ages and Modern
Tawas potassium was imported into England mainly from the Middle East, and, from the late 15th century onwards, the Papal States for hundreds of years. Its use there is as a dye-dye (mordan) for wool (which is one of the major UK industries, whose value increases significantly if dyed).
These sources are unreliable, however, and there is an incentive to develop resources in the UK mainly because imports from the Papal States cease after the excommunication of Henry VIII.
Historically, potassium alum was used extensively in the wool industry of the Classical period, during the Middle Ages, as well as into the 19th century as a mordant or a fixative dye in the process of converting wool into bolts of colored fabrics.
In the 13th and 14th centuries, alum (from alunit) was the main import of Phocaea (Bay of Smyrna in Byzantium) by the people of Genoa and Venice (and was the cause of war between Genoa and Venice) and then by Florence. After the fall of Constantinople, alunite (the source of alum) was found in Tolfa in the Papal States (1461). The textile dyeing industry in Bruge, and many other locations in Italy, and later in England, requires alum to stabilize dyestuffs into fabrics (making "fast dyes") and also to brighten colors.
With state financing, efforts were made throughout the 16th century, but did not work until the early in the 17th century. An industry was established in Yorkshire to cultivate shale, which contained the main ingredient, aluminum sulphate, and made an important contribution to the Industrial Revolution. One of the oldest historic sites for alum production from shale and human urine is Puncak alum working at Ravenscar, North Yorkshire. In the 18th century, the scenery of north-eastern Yorkshire has been devastated by this process, which involves building a 100 foot (30 m) pile of burned flakes and filling them with firewood continuously for months. The rest of the production process consists of excavation, extraction, ash shale with seaweed in urine, boiling, evaporation, crystallization, grinding and loading into sacks for export. Excavations feed into the cliffs in the area, the forests are cleared for charcoal and the soil is polluted by sulfuric acid and ash.
Identify formulas
In the early 1700s, Georg Ernst Stahl claimed that reacting sulfuric acid with limestone produced a kind of alum. The error was immediately corrected by Johann Pott and Andreas Marggraf, which showed that the deposits obtained when an alkali was poured into an alum solution, ie alumina, were very different from chalk and lime, and were one of the materials in ordinary clay.
Marggraf also showed that the perfect crystals with alum properties can be obtained by dissolving alumina in sulfuric acid and adding potas or ammonia to the concentrated solution. In 1767, Torbern Bergman observed the need for potassium or ammonium sulfate to convert aluminum sulfate into alum, while sodium or calcium would not work.
At that time, potassium ("potas") is believed to be exclusively found in plants. However, in 1797, Martin Klaproth discovered the presence of potassium in the mineral leucite and lepidolite.
Louis Vauquelin then suspects that potassium is also an ingredient in many other minerals. Given Marggraf and Bergman's experiments, he suspects that this alkali is an essential ingredient of natural alum. In 1797 he published a dissertation showing that alum is a double salt, composed of sulfuric acid, alumina, and potassium. In the same volume of volumes, Jean-Antoine Chaptall published an analysis of four different types of alum, namely, the Romans, the Levs, the alum and the self-produced English alum, justifying the results of Vauquelin.
Maps Potassium alum
Characteristics
Tawas potassium crystallizes in ordinary octahedra with flat corners and is very soluble in water. The solution is slightly acidic and astringent to the taste. Neutralize the alum solution with potassium hydroxide will start to cause the separation of alumina Al (OH)
3 .
When heated to almost red heat, it provides a porous and friable mass, known as "burning alum". This fuses at 92Ã, Â ° C (198Ã, Â ° â € <â € <) in its own crystallization water.
Natural events
Potassium alum dodecahydrate occurs in nature as a sulfate mineral called alum (K), usually as encrustations in rocks in weathering areas and oxidation of sulfide minerals and potassium-bearing minerals.
In the past, potassium alum has been obtained from alunite ( KAl (SO
4 )
2 Ã, Â · 2Al (OH)
3 ), mined of volcanic sediments containing sulfur. Alunite is an association and potentially a source of potassium and aluminum. It has been reported in Vesuvius, Italy; east of Springsure, Queensland; in Alum Cave, Tennessee; Alum Gulch, Santa Cruz County, Arizona and Cebu island in the Philippines.
To get alum from alunite, it is calcined and then exposed to air action for quite a long time. As long as this exposure is kept continuously moistened with water, it eventually falls into a very fine powder. This powder is then given lixiviated with hot water, the liquid is poured, and the alum allows to crystallize.
The undecahidrat juga terjadi sebagai mineral kalima berserat ( KAl (SO
4 )
2 Â · 11H
2 O ). " Kalinite Mineral Data ". MinDat . Diperoleh 2013-04-19 . & lt;/ref & gt;
Produksi industri
Potassium alum is historically primarily extracted from alunite.
Potassium alum is now industrially produced by adding potassium sulfate to a concentrated aluminum sulfate solution. Aluminum sulfate is usually obtained by treating minerals such as alum sekis, bauxite and cryolite with sulfuric acid. If a lot of iron is present in the sulfate then it is better to use potassium chloride instead of potassium sulfate.
Usage
Drugs and cosmetics
Potassium alum is used in medicine primarily as an astringent (or blood-retardant) and antiseptic.
An antimetic pencil is a stem consisting of potassium or aluminum sulfate alum, used topically to reduce bleeding in minor injuries (especially from shaving) and abrasions, nosebleeds, and hemorrhoids, and to relieve pain from stings and bites. The potassium alum block is rubbed on top of the wet skin after shaving.
Potassium alum is also used topically to get rid of acne and pimples, and to burn thrush in mouth and mouth ulcers, as it has a significant drying effect to the area and lessen the perceived irritation on the site. It has been used to stop bleeding in cases of cystitis hemorrhagic. and is used in some countries as a cure for hyperhidrosis.
It is used in dentistry (especially on gingival retraction ropes) because of its astringent and hemostatic properties.
Potassium and alum ammonium are active ingredients in some antiperspirants and deodorants, acting by inhibiting the growth of bacteria responsible for body odor. Antiperspirant alum and antibacterial properties contribute to its traditional use as axillary deodorant. It has been used for this purpose in Europe, Mexico, Thailand (where it is called sarn-som ), throughout Asia and in the Philippines (where it is called alum ). Today, potassium or ammonium alum is sold commercially for this purpose as a "deodorant crystal". Beginning in 2005, the US Food and Drug Administration no longer recognizes it as a wet damper, but is still available and used in several other countries, especially in Asia.
Tawas potassium is the main auxiliary agent used to improve the efficacy of vaccines, and has been used since the 1920s. But it has been almost completely replaced by aluminum hydroxide and aluminum phosphate in commercial vaccines.
Tawas can be used in depilatory wax used to remove body hair or applied to new skin wax as a soothing agent.
In the 1950s, men wearing crewcut or flattop hairstyles sometimes used alum for their hair, as an alternative to pomade, to keep hair standing.
Culinary
Potassium alum can be a baking powder acid material to provide a second phase of leavening at high temperatures (although the alum sodium is more commonly used for that purpose ).
Alas was used by bakers in England during the 1800s to make white bread. It is theorized by several people, including John Snow, to cause rickets. The sale of the Food and Drug Act of 1875 prevented this and other counterfeits.
Potassium alum, with the name "alum powder", is found in the spice part of many grocery stores in the US. Its main culinary use is in pickled recipes, to preserve and add crispness to fruits and vegetables as preservatives to maintain the crispness of fruits and vegetables.
Flame retardant
Tawas potassium is used as a refractory material to make cloth, wood, and paper material becomes non-flammable.
Tanning
Potassium alum is used in tannery (more precisely, "tawing"), to remove moisture from the skin and prevent decay. Unlike tannic acid, alum does not bind to the skin and can be washed.
Immersion
Tawas has been used since time immemorial as mordan to form a permanent bond between dye and natural textile fibers such as wool. It is also used for this purpose in marbling paper.
Chemical flocculants
Potassium alum has been used since ancient times remote for purification of turbid liquids. It is still widely used in water purification for drinking water and industrial processes, sewage treatment and post-lake storm care to precipitate contaminants.
Between 30 and 40 ppm alum for household wastewater, often more for industrial wastewater, is added to water so that the negatively charged colloidal particles converge into "flocs", which then float to the top of the liquid, settle down the liquid, or can be more easily filtered from the liquid, before further filtration and disinfection of water. Like other similar salts, it works by neutralizing the multiple electrical layers surrounding the very fine suspended particles, allowing them to combine into flocs.
The same principle is exploited when using alum to increase the viscosity of the ceramic glaze suspension; this makes the glaze more easily attached and slows down the rate of sedimentation.
Lake pigment
Aluminum hydroxide from "alum otassium serves as the basis for the majority of lake pigments.
Dissolves iron and steel
The alum solution has the properties of dissolving steel while not affecting aluminum or base metals. The alum solution can be used to dissolve steel tools that have been caught in machine castings, for example.
More
In traditional Japanese art, alum and animal glue are dissolved in water, forming a liquid known as dousa (ja: ??), and used as a bottom layer for paper size.
Tawas is an ingredient in some recipes for homemade modeling compounds intended for use by children. These are often called "playing clay" or "playing dough" because of their similarity with "Play-Doh".
Tawas potas previously used as hardener for photographic emulsion (film and paper), usually as part of fixer. Now it has been replaced with the use of other chemicals.
Toxicology and security
Tawas potassium can be a weak irritation of the skin.
![Potassium Alum [KAl(SO4)2] 99.7% ACS Grade Powder 4 Oz in a ...](https://lh3.googleusercontent.com/blogger_img_proxy/AEn0k_uQadd6jBIeB2OqjskPEGN4sfAFbki0Ems_0xfwETeVLaft3XJeiNasrKon6wkDSr12f3iK8rvc1rSgz6W8AYyf3OsMEJx9bqDY4-a5oLVIXzP2wyqCEijAErdPcwESS5TQVFVusm5mPg=s0-d "Potassium Alum [KAl(SO4)2] 99.7% ACS Grade Powder 4 Oz in a ...")
See also
- Ammonium aluminum sulfate
- Alum
References
Source of the article : Wikipedia
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