Aluminium Hydroxide Structure Properties and Uses

As is known to the majority of individuals, aluminum is a naturally available mineral while Aluminum Hydroxide comes in the form of an antacid. It is suitable for treating upset stomach, acid indigestion, heartburn and sour stomach. You can also use it for reducing the levels of phosphate in people suffering from kidney problems. The antacid might even be suitable for other non-medicinal purposes.

For the ones who do not have any idea about what Aluminum Hydroxide is, it is also known as Aluminum Hydroxide, Aluminum (III) Hydroxide or Aluminic Acid. It is the chemical name of aluminum and just like all the other varieties of metal carbonates, sulfates and hydroxides. It is found naturally as a mineral gibbsite along with its polymorphs called bayerite, doyleite and nordstrandite.

Production of Aluminum Hydroxide

Coming to the properties of aluminium hydroxide, its density is 2.42 g/cm³, and its melting point is 300 degree Celsius. It is an amorphous powder in white colour and is insoluble in water. However, it is soluble in acidic and alkaline solutions. Aluminium hydroxide molar mass is 78.0036.

Aluminium hydroxide that needs to be used commercially is manufactured using the Bayer procedure. The process involves dissolving bauxite in a solution of sodium hydroxide at 270 degree Celsius. 

Once the procedure is completed, waste removal is carried out, leaving the solution of sodium aluminate to precipitate. The mineral obtained through the precipitation is called aluminium hydroxide. Calcination is the process used for obtaining aluminium oxide or alumina from aluminium hydroxide.  

Bayer’s process is used to produce the commercial Aluminum Hydroxide. This is done by dissolving bauxite in a solution of sodium hydroxide at a temperature of say 270 0C. The waste is removed and the sodium aluminate solution is allowed to rise. Therefore, the Aluminum Hydroxide which is formulated is called the precipitate. Alumina or aluminum oxide can be obtained from Aluminum Hydroxide by the calculation process.

Bayer processes almost all the commercially available Aluminum Hydroxide which helps in dissolving the bauxite in sodium hydroxide at a temperature of up to atmospheric 2700C (518 0F). The extraction of Aluminum Hydroxide is done from which the solid waste, bauxite tailings, are removed from the remaining solution of sodium aluminate. This Aluminum Hydroxide can be converted to Aluminum oxide or alumina by calculation.

Aluminum Hydroxide Structure

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Once you are aware of aluminium hydroxide properties, it is time for you to get a clear understanding of the chemical formula of aluminium hydroxide and aluminium hydroxide structure. 

Aluminium Hydroxide formula is Al OH3. It goes like this:

\[Al OH_{3} {\text{acid or base}} + 3 H – Al^{+}_{3} + H_{2}O (I)\]

\[Al (OH)_{3} + OH^{-} - AlO_{2}^{-} + H_{2}O (II)\]

The typical structure of aluminium hydroxide consists of the bonds of hydrogen and dual covers of aluminium ions and hydroxyl groups. These occupy around two-third of the octahedral holes available within the two layers. The amphoteric Gibbsite works in the form of a Bronsted-Lowry base for yielding a certain salt through the pick-up of hydrogen acids and the neutralization of the same. A reaction follows the procedure, which is:

\[3 HCl + Al (OH)_{3} - AlCl_{3} + 3 H_{2}O\]

What are the Precautions You Need to Maintain during the Preparation of Aluminum Hydroxide Gel?

• The person who is making the preparation must clean the conical flask to avoid dirt and germs through the process of hot boiling.

• The deterioration of the repaired gel leads to the production of the by-product (Hydrochloric Acid) in the reaction. Therefore, it needs to be removed through the dialysis process.

• The downward spiral needs to be added to the Aluminum chloride solutions.

Preparation

It is not necessary to prepare aluminium hydroxide as it is present in huge abundance in different geological systems. Nevertheless, it is produced using the sintering and Bayer procedures for obtaining alumina from mineral bauxite. Therefore, 97% of aluminium hydroxide found in the world comes from the treatment of caustic soda and bauxite. The process yields sodium aluminate, which is further decomposed using the stirring procedure for obtaining aluminium hydroxide. The formula goes like this:

\[NaAl (OH)_{4} – Al (OH)_{3} + NaOH\]

There are other procedures also used for obtaining aluminium hydroxide, and these include Sol-gel or micro-emulsion and hydrothermal procedures. Using these procedures can help in generating aluminium hydroxide with higher levels of purity.

Step by Step Preparation of Aluminum Hydroxide Gel

• The Aluminum chloride solution is needed to be prepared with a minimum of 2% (by adding 2g of Aluminum chloride to 100 ml of water).

• The conical flask must contain at least 100ml of distilled water.

• The wire gauze must be used to boil water.

• Add 10 ml of the above 2% prepared solution of Aluminum chloride. Add this solution with the help of a burette dropper. Like aluminum, composites are naturally violent.

• The solution must be shaken regularly with the addition of Aluminum chloride.

• The color of the solution must be noted while heating the solution and the color of the Aluminum Hydroxide solution must be white.

• Leave the mixture to cool to room temperature.

• The cooling solution is called Aluminum Hydroxide gel.

Aluminium Hydroxide Uses

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There are a plethora of uses of aluminium hydroxide in the chemical industry. The pharmaceutical and chemical uses of aluminium hydroxide include:

• You can use it in the form of an antacid for treating ulcers and gastritis.

• You can also use it as an additive in different vaccines.

• Aluminium hydroxide also works in the form of an excipient during the process of manufacturing certain drugs.

• The most common use of this formula is in the form of a raw material in the manufacture of aluminium oxide or alumina which further helps in the production of aluminium metal.

• It is used in gel form.

• As a filler in different cosmetics.

• For the manufacture of activated alumina.

• In the form of a chemical intermediate.

• Aluminium hydroxide is in use as an additive in glass for increasing thermal shock resistance.

• As a flame retardant and soft abrasive for plastics.

• It is also used on a very wide scale in different water-resistant fabrics and the manufacture of paper.

Aluminum Hydroxide Side Effects

There are large-scale aluminium hydroxide side effects that users need to be aware of. High concentrations of the same can cause a lot of health damages. It might even damage the lungs and result in allergic reactions like swelling of the tongue, lips, throat and face; hives and breathing difficulty. Other side effects of using aluminium hydroxide include:

• Pain while urinating

• Severe pain in the stomach or constipation

• Appetite loss

• Tiredness and muscle weakness

• Tarry or bloody stools

• Coughing blood

• Vomiting

• Extreme drowsiness

If you witness any of these side effects, you must get emergency help as soon as possible. Even better, consult your healthcare professional before taking anything with high concentrations of the mineral.

You Must Not Know These, Did You Know Facts Until Now?

• The base and acid are both the reactants of Aluminum Hydroxide.

• Aluminum Hydroxide is used to cover TiO₂ nanoparticles.

• Aluminum Hydroxide is used to reduce phosphate levels in people with certain kidney conditions.

• The use of Aluminum Hydroxide reduces the absorption of other chemicals in the body. Therefore, spaces of two hours before and after taking Aluminum Hydroxide should be retained for further use in this regard.