What Is Aluminum Silicate?
Aluminum Silicate is the general term for a mixture of aluminum oxide, silicon dioxide, and water. It is found in a variety of compositions and is abundant in nature.
Aluminum silicate is sometimes used to refer to the calcite alone. Calcite is a white orthorhombic crystal at room temperature and insoluble in water. It is resistant to acids and bases and is not eroded.
There are natural aluminum silicates and artificially synthesized aluminum silicates of various compositions.
Uses of Aluminum Silicate
In addition to its use as a raw material for ceramics and paints, synthetic aluminum silicate is also used in medicine.
In its pharmaceutical form, synthetic aluminum silicate is often used as a medicine to reduce inflammation of the stomach and intestines. It tends to be avoided in patients with kidney problems because of the possibility of developing side effects such as kidney stones when administered over a long period of time.
Aluminum silicate fiber is also attracting attention for its low thermal conductivity and excellent thermal and chemical stability.
Properties of Aluminum Silicate
Aluminum silicate is generally an odorless white solid. In its natural mineral form, it is considered safe and non-toxic.
However, prolonged exposure to aluminum silicate dust can cause respiratory problems such as silicosis. Silicosis is a lung disease that causes scarring of lung tissue and reduced lung function and may also increase the risk of lung cancer.
Some forms of aluminum silicate, such as synthetic forms like zeolite, can be chemically altered and pose a significant risk to human health.
When handling aluminum silicate, it is important to use appropriate personal protective equipment such as masks to prevent exposure.
Types of Aluminum Silicate
Aluminum Silicate is available in many minerals and compounds that vary in composition and structure.
Common types of aluminum silicate include:
1. Kaolinite
A clay mineral commonly found in soils and used in the manufacture of pottery, paper, and other materials.
2. Andalusite
This mineral crystallizes at lower pressures than kyanite and lower temperatures than sillimanite. The crystalline system is orthorhombic.
3. Kyanite
Similar in composition to andalusite, kyanite is sometimes used in decorative objects. The crystalline system is triclinic.
4. Sillimanite
Sillimanite is orthorhombic in crystal system. It has the same composition as kyanite and andalusite, but a different crystal structure.
5. Zeolite
A highly porous, synthetic aluminum silicate used as a catalyst, adsorbent, and ion exchanger.
6. Mica
A group of minerals with excellent heat resistance and insulating properties often used in cosmetics, insulation, and electronics.
7. Feldspar
This mineral group is commonly used in the manufacture of ceramics and glass due to its low melting point and ability to reduce thermal expansion.
There are many other types of aluminum silicate minerals and compounds, each with its own unique properties and uses.
Structure of Aluminum Silicate
Aluminum Silicate compounds are generally composed of a three-dimensional network consisting of an octahedron composed of one aluminum atom and six oxygen atoms and a tetrahedron composed of one silicon atom and four oxygen atoms. Depending on the chemical composition and the morphology of the network structure, it yields a variety of properties.
The network structure depends on the type of aluminum silicate. For example, in the mineral kaolinite, silicon tetrahedra are arranged in layers, with aluminum octahedra between the layers. In contrast, zeolites have an infinite series of SiO4 or AlO4 tetrahedral structures.