What is chromic alum? Where to buy and why they are used

Alums are called double salts, which include metals. These are octahedral crystals, which have long been used in medicine and in industry. The chemical composition includes one of alkali metals and a trivalent metal. Crystalline sulfate crystals are obtained by combining hot solutions of certain metals, which upon crystallization crystallize into alum.

Chromo-potassium alum: what it is and why

Crystals of dark purple octahedral form form chromic alum alum - one of the most common of their representatives. When the solution is heated, the salt crystals are dehydrated and converted into a light violet powder. The aqueous solution has an acidic taste. The name of the crystals comes from the word "kvass", "sour". Depending on the conditions, alum chromokalic can change color from saturated purple to dark green. For example, the black-violet powder changes color towards green when heated, and changes to purple when cooled.

It was discovered long ago that a tree dropped into a solution of chromic acid alum, after drying it, exhibits refractory properties. In ancient Greece, chromic alum was known for dressing skins, coloring wool and cotton fabrics and yarn. Therefore, they are used as a tanning agent in the process of manufacturing furs by handicraft production, for the preparation of emulsions and as a tanning fixer. Such properties are determined by their ability to denature the protein.

What is alumokalievye alum

Alumokali alums are crystals without color or a 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 with further heating, turning into oxides, secrete sulfuric acid. Such crystalline hydrates have found application in the preparation of sulfuric acid.

Alum kalum alum in medicine

Alumokalic alum has also been common in medicine for a long time. They show a hemostatic effect for various wounds and cuts. The fact of their use by ancient alchemists and pharmacists in Europe and Asia is known for stopping bleeding. Now they release the product in the form of an alum stick, which has a hemostatic, drying and antiseptic effect. Alumokalic alum is also used in the treatment of varicose veins.

Where to buy alum

Especially popular are chromic alum in the textile industry, so there are many substance manufacturers. The choice is great. The Internet offers many businesses that produce chromium-alum, where they can be bought today easily and quickly. You can also choose packing and packing type of alum. Producers of crystals, where you can buy them, are the following:

- "Vitahim", Yekaterinburg.

- "AquaChem", Moscow, st. Voroshilov Str. 40.

- "Yugraaktiv", Rostov-on-Don.

- "Cryohim", St. Petersburg.

- "Promkhimperm", the city of Perm.

- "Component-reagent", Moscow.

- "UfaHimProject", Ufa.

In these companies, as well as in online stores, it is possible to purchase chromium-potassium alum, the price of which depends on their quantity and producer. One kilogram of alum can be purchased at a price of 450-550 rubles.

Storage conditions

The substance can be purchased from 200 g to 25 kg, packed in cellophane bags or bags, as well as kraft bags. Sometimes alum is packed in jars with dark glass. Retail buyers purchase crystals with a packing of 1 kg for leather and textile production. The substance, because of its characteristics, should be stored in dry conditions in a well-ventilated room in bags of cellophane or paper. If you do not comply with these simple conditions, then alum weathering and lose their useful properties. Alum chromosomes are stored for a period of up to 2 years. Also they are offered in the form of a deodorant or alum stick, they are bought in pharmacies of any city or via the Internet.

How do crystals appear

The powder of chromium-potassium alum is colored in a dark purple color, and its solution has a dark green color. Put the powder, water and thread in the glass. The container with the solution of the substance is colored 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 monocrystals. Crystals appear because of the precipitate that precipitates in the solution. Colorless alumokalievye alum is also used for growing crystals. Interesting shades give a mixture of chromium and aluminum alum from lilac and pink to violet.

Application of the substance

The alum and chromium alum in the modern world found the following use:

- as a tanning substance for hides;

- when dressing fur;

- in the manufacture of photography;

- as a dye for ceramics;

- in medicine as a hemostatic, anti-inflammatory and astringent;

- in the manufacture of antiperspirant deodorants and after shave preparations;

- in the textile industry as a mordant.

They are useful during water treatment and as a disinfectant for the food industry. Alumokalievye and kremokalievye alum and today found their place in industry and medicine. But still more common are alumokalievye. Many companies now provide in the online stores and directly to the company ready-made chromic-calcium alum, where you can buy them at any time.