Where can I Find Alum?

Potassium alum is the common alum of commerce, although soda alum, ferric alum, and ammonium alum are manufactured. Alum has been used at least since Roman times for purification of drinking water2 and industrial process water. Between 30 and 40 ppm of alum23 for household wastewater, often more for industrial wastewater,4 is added to the water so that the negatively charged colloidal particles clump together into "flocs", which then float to the top of the liquid, settle to the bottom of the liquid, or can be more easily filtered from the liquid, prior to further filtration and disinfection of the water.

Alum in block form (usually potassium alum) is used as a blood coagulant. Styptic pencils containing aluminium sulfate or potassium aluminium sulfate are used as astringents to prevent bleeding from small shaving cuts. For example, alum blocks are commonly sold in pharmacies in India.

Alum may be used in depilatory waxes used for the removal of body hair, or applied to freshly waxed skin as a soothing agent. In the 1950s, men sporting crewcut or flattop hairstyles sometimes applied alum to their front short hairs as an alternative to pomadecitation needed. When the hair dried, it would stay up all day.

Alum's antiperspirant and antibacterial properties56 contribute to its traditional use as an underarm deodorant. 7 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 Tawas. Today, potassium or ammonium alum is sold commercially for this purpose as a "deodorant crystal," often in a protective plastic case.

Alum was used as a base in skin whiteners and treatments during the late 16th century. "For the Freckles which one getteth by the heat of the Sun: Take a little Allom beaten small, temper amonst it a well brayed white of an egg, put it on a milde fire, stirring it always about that it wax not hard, and when it casteth up the scum, then it is enough, wherewith anoint the Freckles the space of three dayes: if you will defend your self that you get no Freckles on the face, then anoint your face with the whites of eggs." —Christopher Wirzung, General Practise of Physicke, 1654. Alum is used in many subunit vaccines as an adjuvant to enhance the body's response to immunogens.

Such vaccines include hepatitis A, hepatitis B, and DTaP. Alum in powder or crystal form, or in styptic pencils, is sometimes applied to cuts to prevent or treat infection. Powdered alum is commonly cited as a home remedy for canker sores.

Preparations containing alum are used by pet owners to stem bleeding associated with animal injuries caused by improper nail clipping. Alum is listed as an ingredient of some brands of toothpaste or toothpowder. Alum powder dissolved in five parts water has been used to shrink hemorrhoids and stop them from bleeding.

Alum is added to water for gargling to help relieve sore throat . Alum powder, found in the spice section of many grocery stores, may be used in pickling recipes as a preservative to maintain fruit and vegetable crispness. Alum is used as the acidic component of some commercial baking powders.

Alum was used by bakers in England during the 1800s to make bread whiter. 9 The Sale of Food and Drugs Act 1875 prevented this and other adulterations. Solutions containing alum may be used to treat cloth, wood, and paper materials to increase their resistance to fire.

Alum is also a component of foamite. Alum is also used in fire extinguishers to smother chemical and oil fires. Alum is used to clarify water by neutralizing the electrical double layer surrounding very fine suspended particles, allowing them to flocculate (stick together).

After flocculation, the particles will be large enough to settle and can be removed. Alum may be used to increase the viscosity of a ceramic glaze suspension; this makes the glaze more readily adherent and slows its rate of sedimentation. Alum is an ingredient in some recipes for homemade modeling compounds intended for use by children.

(These are often called "play clay" or "play dough" for their similarity to "Play-Doh", a trademarked product marketed by American toy manufacturer Hasbro). Alum is used in the tanning of animal hides to remove moisture, prevent rotting, and produce a type of leather. The word "alumen" occurs in Pliny's Natural History.

In the 52nd chapter of his 35th book, he gives a detailed description. 7 By comparing this with the account of stupteria given by Dioscorides in the 123rd chapter of his 5th book, it is obvious that the two are identical. Pliny informs us that alumen was found naturally in the earth.

He calls it salsugoterrae. Different substances were distinguished by the name of "alumen"; but they were all characterised by a certain degree of astringency, and were all employed in dyeing and medicine, the light-colored alumen being useful in brilliant dyes, the dark-colored only in dyeing black or very dark colors. 7 One species was a liquid, which was apt to be adulterated; but when pure it had the property of blackening when added to pomegranate juice.

This property seems to characterize a solution of iron sulfate in water; a solution of ordinary (potassium) alum would possess no such property. Pliny says that there is another kind of alum that the Greeks call schiston, and which "splits into filaments of a whitish colour",7 From the name schiston, and the mode of formation, it appears that this species was the salt which forms spontaneously on certain salty minerals, as alum slate and bituminous shale, and which consists chiefly of sulfates of iron and aluminium. Citation needed Possiblyvague in certain places the iron sulfate may have been nearlyvague wanting, and then the salt would be white, and would answer, as Pliny says it did, for dyeing bright colors.

Several other species of alumen are described by Pliny, but wewho? Are unable to make out to what minerals he alludes. The alumen of the ancients, then, was not always the same as the alum of the moderns.

They certainly knew how to produce alum from alunite, as this process is archaeologically attested on the island Lesbos. 11 This site was abandoned in the seventh century but dates back at least to the second century CE. Native alumen from Melos appears to have been a mixture mainly of alunogen (Al2(SO4)3·17H2O) with alum and other minor sulfates.

12 The western desert of Egypt was a major source of alum substitutes in antiquity. These evaporites were mainly FeAl2(SO4)4·22H2O, MgAl2(SO4)4·22H2O, NaAl(SO4)2·6H2O, MgSO4·7H2O and Al2(SO4)3·17H2O. 13 Any contamination with iron sulfate was greatly disliked as this darkened and dulled dye colours.