Alum is called double salts, which include metals. These are octahedral crystals that have long been used in medicine and in industry. The chemical composition includes one of the alkali metals and trivalent metal. Sulfate crystalline hydrates are prepared by combining hot solutions of certain metals, which crystallize into alum upon cooling.
Potassium alum: what is it and what is it for
Dark violet crystals of an octahedral form form chromium potassium alum - one of their most common representatives. When the solution is heated, salt crystals are dehydrated and turn into a light purple powder. The aqueous solution has a sour taste. The name of the crystals comes from the word "kvass", "kvass". Depending on the conditions, chromium potassium alum can change color from saturated violet to dark green. For example, a black-violet powder changes color to green when heated, and changes to purple when cooled.
It was discovered long ago that a tree dipped in a solution of chromium-potassium alum, after drying, exhibits refractory properties. In ancient Greece, potassium alum was known for dressing hides, dyeing wool and cotton fabrics and yarn. Therefore, they are used as a tanning agent in the process of making fur artisanal production, for the preparation of emulsions and as a tanning fixer. Such properties are determined by their ability to denature protein.
What is potassium alum
Alum potassium alumina is called colorless crystals or their white powder. Easily soluble in water and incompatible with tannins, salts of mercury and lead. When heated, they begin to melt, turn into salts, and upon further heating, turning into oxides, they release sulfuric acid. Such crystalline hydrates are used in the preparation of sulfuric acid.
Potassium alum in medicine
Potassium alum is also common in medicine for a long time. They exhibit hemostatic effect for various wounds and cuts. The fact of their use by ancient alchemists and pharmacists in Europe and Asia is known to stop bleeding. Now they release a tool in the form of an alum pencil, which has a hemostatic, drying and antiseptic effect. Also, potassium alum is used in the treatment of varicose veins.
Where to buy alum
Potassium alum is especially popular in the textile industry, so there are many manufacturers of the substance. The choice is great. The Internet offers many enterprises that produce potassium chromium alum, where you can buy them easily and quickly today. You can also choose the packaging and type of packaging of alum. The manufacturers of crystals where you can buy them are as follows:
- "Vitahim", Ekaterinburg.
- "AquaHim", Moscow, st. Voroshilova, 40.
- "Yugreaktiv", Rostov-on-Don.
- "Cryochem", St. Petersburg.
- "Promkhimperm", Perm.
- "Component reagent", Moscow.
- "UfaKhimProekt", Ufa.
In these companies, as in online stores, you can purchase potassium chromium alum, the price of which depends on their quantity and manufacturer. One kilogram of alum can be purchased at a price of 450-550 rubles.
Storage conditions
The substance can be purchased in quantities of 200 g to 25 kg, packaged in plastic bags or bags, as well as kraft bags. Sometimes alum is packaged in jars with dark glass. Retail customers purchase crystals in 1 kg packaging for leather and textile industries. Due to its characteristics, the substance should be stored in dry conditions in a well-ventilated room in bags of cellophane or paper. If these simple conditions are not observed, then the alum will erode and lose their beneficial properties. Potassium alum is stored for up to 2 years. They are also offered in the form of a deodorant or alum pencil, bought in pharmacies of any city or via the Internet.
How do crystals appear?
The powder of chromium-potassium alum is colored dark purple, and its solution has a dark green color. Powder, water and thread are placed in a glass. The container with the solution of the substance is painted black, through which its contents are not visible. In the solution there is a seed with a substance that is placed in a glass for growing single crystals. Crystals appear due to a precipitate that precipitates in solution. Colorless potassium alum is also used to grow crystals. A mixture of chrome-potassium and aluminum alum from lilac and pink to purple gives interesting shades.
Substance use
Alum chromium-potassium and aluminum-potassium in the modern world have found the following use:
- as a tanning agent for hides;
- when dressing fur;
- in the manufacture of photographs;
- as a dye for ceramics;
- in medicine as a hemostatic, anti-inflammatory and astringent;
- in the manufacture of antiperspirant deodorants and after shave products;
- in the textile industry as a mordant.
They are useful during water treatment and as a disinfectant for the food industry. Alumino-potassium and chromium-potassium alum today have found their place in industry and medicine. But still, potassium aluminum remains more common. Many companies now provide ready-made chrome-potassium alum in online stores and directly at the company, where you can buy them at any time.