What is Potassium Alum E522? Uses, Safe, Side Effects

What is Potassium Alum E522? Uses, Safe, Side Effects


Table of Contents

Potassium alum, also known as potassium aluminum sulfate, potassium alum crystal, potassium alum salt, and KA, is a chemical compound with the formula KAl(SO4)2.12H2O. It is used as a food additive and preservative and it has various applications such as chemical intermediate, thatching of roofs, and theatre effects (explosions).

If you’re looking for more information about Potassium Alum E522, you’ve come to the right place. Read on for details about this mineral, as well as its uses, side effects, and safety precautions.

What is potassium alum?


Potassium alum is an ingredient used in making deodorants, toothpaste, and other cosmetics. It is also known as potassium aluminum sulfate or potassium alumina. Its chemical formula is KAl(SO4)2.12H2O and it has a molecular weight of 493.7 g/mol.

The potassium alum is the potassium salt of aluminum sulfate (alum). Potassium alum may contain up to 30% water. In its pure form, it appears as small, transparent crystals or colorless to white-gray powder. When heated it turns brown and then black, but returns to its original state when allowed to cool again.

What is potassium aluminum sulfate?


Potassium aluminum sulfate (Alum) is the most common product used to make a slurry of alum, which is an astringent liquid. The astringent properties of this chemical have been used for centuries to treat diarrhea, vomiting and other gastrointestinal disorders.

It is also used as an emetic – a substance that induces vomiting – to induce vomiting in people who are poisoned with toxic chemicals or other substances that can be removed from their bodies by inducing vomiting.

The chemical is used in dyeing fabrics and hair, tanning leather and preserving foods such as pickles and olives. It has also been used as a fixative in perfumes and aftershave lotions due to its tendency to form a protective coating on the skin or hair shafts.

What is potassium alum used for?


Potassium alum is a natural mineral salt that can be used as an astringent, a deodorant and a styptic. It is made from alumina and potassium hydroxide, which is dissolved in water and heated to form a gel. Potassium alum has been used for centuries as a cosmetic product. It may be found in soap, shampoo, and toothpaste.

The uses of potassium alum include:


Bath and body products. Alum is often used as a deodorant and astringent in body care products such as soap, shampoo, and shaving cream.

Food preservative. Alum can be added to pickles, jams, and other foods to prevent bacterial growth.

Water treatment. Alum is used in some water treatment systems to remove particles from raw water entering the facility. It may also be added to the final product to help remove odors or colors from drinking water.

Treating wounds, cuts, and abrasions by applying it directly to the skin. It helps stop bleeding by tightening blood vessels and slowing blood flow. This reduces inflammation and speeds healing time.

Reducing bleeding during surgery by applying it directly to the tissue before stitching up incisions.

Treating diarrhea caused by bacterial infections by adding it to water before drinking the water.

As a mild astringent used in skin care products, such as aftershave lotions, bath soaps, and shaving creams.

How is potassium alum made?


The potassium alum is available in two forms: natural and synthetic.

In the natural world, salt appears as encrustations on rock surfaces (alunite) as a result of chemical reactions between sulphides and potassium. From such natural stones, it can be extracted. After extraction, the crystals are dissolved in water to remove impurities and concentrated and dried.

Alum can be synthesized by combining potassium sulfate and aluminum sulfate solutions, followed by evaporation to crystallize potassium alum. This is the chemical equation for the reaction: Al2(SO4)3 + 3K2SO4 + 24H2O = 2KAl(SO4)2 * 12H2O

Sulfuric acid is commonly used to produce aluminum sulfate from bauxite ore (the main component of aluminum oxide). The chemical equation for this reaction is: Al2O3 + 3H2SO4 = Al2(SO4 )3 + 3H2O

Anhydrous aluminium potassium sulfate can be obtained by heating the dodecahydrate form to 200 °C to remove crystal water, but too high a temperature will produce aluminium oxide.


Other names Potash alum
CAS number 7784-24-9
Chemical formula KAl(SO4)2 (anhydrous), KAl(SO4)2·12H2O (dodecahydrate)
Molecular weight 258.21 (anhydrous), 474.38 (dodecahydrate)



It is a white crystalline powder or large, transparent crystals that taste bitter.


potassium alum structure



Unlike anhydrous forms of dodecahydrate, which are slowly soluble in cold water, but easily soluble in hot water, dodecahydrate is freely soluble in water. In ethanol, both types are insoluble.

Can potassium aluminum sulfate be classified as acidic or basic?


The PH of the acid is between 3.0 and 4.0 (10 % solution). It dissociates Al3+ in water and releases H+ when it reacts with water. This is the equation for the reaction:

Al3+ + 3H2O — AI(OH)3 + 3H+

What’s the application of potassium alum?

Potassium alum is a multifunctional ingredient that can be found in crystal deodorants, baking powder, cosmetics, and as an astringent agent for wound healing, water purification, tanning leather, and dyeing.


Sodium aluminum sulfate acts as a slow-acting leavening acid in baked goods, releasing carbon dioxide when heated in the oven, like sodium aluminum sulfate, but it is used less than the former.

Additionally, it can be used in pickling to preserve fruit and vegetable crispness.

Europe limited the use in food

Due to the change in legislation coming into effect in February 2014, the use of aluminium sulfate (E520), aluminium sodium sulfate (E521), aluminium potassium sulfate (E522), and aluminium ammonium sulfate (E523) in food is decreasing over time in Europe.

China also restricted its uses

In July 2014, China banned aluminum compounds – acidic sodium aluminum phosphate, sodium aluminosilicate, and aluminum octenyl succinate starch – from being used as food additives. Aluminum-containing food additives shall not be used in the production of puffed foods in the future.

Aside from fried noodles, batter, breading flour, and frying powder, the use of potassium aluminum sulfate and ammonium aluminum sulfate is forbidden. Potassium aluminum sulfate was commonly used to make steamed buns and fried dough sticks.

In China, these two aluminum sulfates were commonly used in the processing of fried foods and puffed foods. A large amount of aluminum can enter the body and cause problems such as memory loss, mental retardation, slow movement, or even neurological disorders – Alzheimer’s.


A maximum of 0.1g (as aluminum) per kg in bread, moist cakes and confections have also been prohibited by the Japanese Ministry of Health, Labor, and Welfare since August 27, 2018.


Pharmaceutical grade has been used for thousands of years to stop bleeding of small cuts due to its astringent, styptic, softening, and healing properties. In some cosmetics – such as natural aftershaves – this property is also used.

Aside from wounds, tonsillitis, and acne, it can also be used as an antiseptic.


Crystal deodorants often contain potassium alum as the main ingredient. Astringents are agents that tighten pores and reduce perspiration (not antiperspirants that reduce sweat production) by killing bacteria that cause sweat to produce bad odors.

It is an ideal deodorant for armpits, hands, and feet. Potassium alum deodorant contains aluminum, although it contains only a small amount.

Additionally, it can be used to formulate other cosmetics and personal care products, such as aftershave products, skin care products, and moisturizers that induce a tightening sensation.

aluminum chloride VS chlorohydrate VS zirconium

In comparison to aluminum chloride, aluminum chlorohydrate, and aluminium zirconium, which can pass through the skin’s pores and be absorbed, potassium alum is much larger and can therefore hardly be absorbed by the skin.

Additionally, aluminum salts block sweat glands and ducts, preventing perspiration by forming a gel on the skin.

Other applications

  • Dyeing: Used to stabilize colors on both animal protein fibers (such as wool) as well as cellulose fibers (such as cotton, linen, and hemp).
  • Purification of drinking water
  • Inks
  • Leathers
  • Tanning

Is potassium alum safe to eat for the body?

In its pure form, potassium alum is safe to eat. However, it’s not considered a food additive and is not approved for human consumption. The Food and Drug Administration only approves substances that are safe for consumption as food additives.

When potassium alum is ingested by humans in large amounts, it can cause irritation of the mouth and gastrointestinal tract. If you have an open wound or have swallowed large amounts of potassium alum, seek medical attention immediately.


When used in accordance with good manufacturing practices, it is generally recognized as safe (GRAS).  The FDA approved potassium alum as a food additive in 1978, so it can be found in some foods such as fruit preserves, pickles, and jams. In addition to preserving food, potassium alum may also be added to foods like potato chips and pretzels to prevent them from becoming soggy after freezing or heating up in microwave ovens.


In the Commission Regulation (EU) No 231/2012, aluminum potassium sulfate (E522) is listed as an authorized food additive under the category “Additives other than colors and sweeteners”.

Safety re-evaluation in 2018

Based on the currently authorized uses and use levels, EFSA found that aluminum potassium sulfate poses no safety concern.


Classification: food additives, acidity regulators, raising agents, firming agents.

The ADI has not been allocated since 1978.

What is the side effects of potassium alum?

Potassium alum is available in many different forms including powder, crystal or pastes forms. It may also be used as part of a topical treatment regimen with other treatments such as glycolic acid or retinol products.

The side effects of potassium alum include:

Allergic reactions. Take potassium alum only if you are not allergic to it or any other ingredient of the product. If you have an allergy, ask your doctor before using potassium alum.

Skin irritation (burning, redness, and swelling) at the site of application. If signs of skin irritation occur, stop using the product and consult a physician for advice.

Gastrointestinal problems (vomiting, diarrhea). If symptoms persist for longer than a few days or worsen, seek medical attention as soon as possible.

Hives (urticaria). This is a skin reaction that causes itchy red bumps or hives on your skin. These usually appear within minutes after contact with potassium alum. Hives may also occur as a result of an allergy to other substances such as shellfish or latex.

Swelling (angioedema). This can occur at any time — even if you have never had swelling before — and can cause serious breathing problems if it affects the lining of your throat or airways. If you have swelling that affects your airways, seek emergency medical attention right away.

Anaphylaxis. This is a life-threatening allergic reaction that occurs suddenly and quickly worsens if not treated right away with epinephrine (adrenaline) shots and breathing support while waiting for emergency medical help to arrive.

Is potassium alum bad for you?

The short answer is no, potassium alum is not bad for you. Potassium alum is an aluminum-based mineral salt, also known as potassium aluminium sulfate. It’s been used in a variety of ways over the years, including as a hair dye, food additive, and astringent (tissue toner).

The compound is widely considered to be safe, but it can cause skin irritation if it comes into contact with broken skin or eyes. It may also cause respiratory problems if inhaled in large quantities.

Potassium alum can cause problems if taken internally. In high doses, it can cause nausea and vomiting or even death from cardiac arrest.

Where to buy potassium alum?

Potassium alum is a popular water purifier and natural antiseptic. It is also used in food preparation and cooking as well as for tanning leather. The mineral can be bought from most health food stores, but it will be more expensive than if you buy it online.

Here are some places where you can find potassium alum online:

Amazon – Amazon sells bulk quantities of potassium alum at an affordable price. The product usually comes in 25 lb bags, which can be enough for many people who use this mineral regularly. You can also buy smaller amounts of the mineral if needed.

Grade Chemical – Grade Chemical is one reliable potassium alum manufacturer& supplier in China. they can supply you with a large quantity of potassium alum at a more competitive price than local suppliers.

Frequently Asked Question

Is potassium alum toxic?

Potassium alum (alum) is not toxic to humans. It has been used for centuries in the manufacture of food and household products, including pickles, candies, and baking powder. In fact, potassium alum is one of the few food additives that is required by law to be listed on product labels.

How much potassium is allowed per day?

The recommended amount of potassium for adults is 4,700 milligrams (mg). That’s about 3.4 grams. You should get about 99% of your daily potassium from food, and only 1% from supplements.

But there are some exceptions: If you’re pregnant or breastfeeding, you need more potassium than the average adult—about 5,100 mg a day. And if you have kidney disease or heart disease, your doctor may recommend an even higher amount of potassium than that.

How potash alum is prepared?

Potash alum can be prepared in a number of ways. The first step involves dissolving potash or ammonia from salt crystals in water, and then adding alumina (aluminum oxide) to the solution. The resulting mixture is boiled until it becomes thick and gelatinous, at which point it will have formed into a gel-like substance known as potash alum.

How potash alum purifies water?

Potash alum is an inorganic salt which has the ability to bind with certain compounds and remove them from water. This makes potash alum a good water purifier, as it will remove compounds like iron, copper and manganese from water.

Potash alum is most commonly used for industrial applications, such as purifying water for processing in factories or plants.

How does potassium alum deodorant work?

Potassium alum deodorant works by neutralizing odors with a combination of aluminum and potassium.

When you apply the product, it reacts with your skin to form an invisible barrier that keeps odor-causing bacteria from reaching your armpits. This process also helps to keep your skin moisturized, which helps prevent irritation and itching.

What is potassium alum in deodorant?

Potassium alum is an ingredient in deodorant that helps to keep your underarms dry and odor-free. It has been used in this way for centuries, and there’s a reason: it works!

Potassium alum can be found under several different names, including potassium aluminum sulfate (Alum), potassium aluminum sulphate, potassium aluminium sulphate, potassium aluminium sulphate and aluminum potassium sulphate. The chemical formula for potassium alum is KAl(SO4)2.

Does potassium alum have aluminum in it?

Yes, potassium alum does have aluminum in it. Potassium alum is a common name for aluminum potassium sulfate, an ingredient in many deodorants and antiperspirants. It works by blocking your pores to prevent sweat from escaping through them.


Thank you, readers, for taking the time to get a better understanding of potassium alum E522. While it’s been around for quite some time, it is still not very well known by food service and household industry professionals alike. Despite its potential as an alternative to dangerous chemical leavening agents, potassium alum has yet to gain much traction in the market. Additionally, food service professionals need to tread carefully while cooking with E522 since there are different grades of quality available on the market; if your supplies come from a reputable source you’ll be just fine.

If you have any thoughts or feedback on the potassium alum? Let us know in the below comments.

Sophie Feng

Sophie Feng

Sophie Feng is the author of gradechemical.com, she is the co-founder of the grade chemical network. She has been in grade chemical company since 2017, with a working knowledge of food chemical .

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