Magnesium aluminum silicate is an naturally occurring mineral refined from certain types of clay. It's a complex silicate with varying proportions of magnesium, aluminum, silicon, and oxygen, often with associated water molecules (hydrated). The general formula is often represented as Al₂Mg₃O₁₂Si₆ or similar variations depending on the specific type.
Here's a breakdown of its key aspects:
Properties:
- Appearance: Typically a white to off-white fine powder or granules. Some forms can appear as small, soft, slippery flakes.
- Odor and Taste: Odorless and tasteless.
- Solubility: Practically insoluble in water and ethanol, but dispersible in water. It can be soluble in mineral acids.
- pH: Aqueous suspensions are typically alkaline, with a pH around 9.0-10.0 for a 5% solution.
- Viscosity: Forms viscous colloidal dispersions in water. Different types of magnesium aluminum silicate exhibit varying viscosities.
- Absorption: Possesses high absorption capacity, particularly for oils and sebum.
- Stability: Stable indefinitely when stored under dry conditions and over a wide pH range (though unsuitable for highly acidic solutions below pH 3.5).
- Thixotropy: Aqueous dispersions can be thick in a static state but become easily spreadable when shear force is applied (stirring, application).
Uses:
Magnesium aluminum silicate is a versatile ingredient with applications in various industries, primarily due to its thickening, stabilizing, and absorbent properties:
- Cosmetics and Personal Care Products:
- Thickening Agent and Viscosity Controller: It increases the thickness and improves the texture of creams, lotions, gels, masks, shampoos, conditioners, and toothpaste.
- Emulsion Stabilizer: Helps to prevent the separation of oil and water phases in emulsions.
- Absorbent: Absorbs excess oil (sebum) and impurities from the skin, making it useful in cleansers, masks, and products for oily skin.
- Suspending Agent: Helps to keep insoluble particles (like pigments and exfoliants) evenly dispersed in liquid formulations.
- Binding Agent: Used in pressed powders to help them adhere.
- Opacifying Agent: Can impart an opaque appearance to products.
- Skin Feel Enhancer: Contributes to a smooth, creamy, and non-tacky feel on the skin.
- Pharmaceuticals:
- Antacid: Used in some over-the-counter antacid medications to neutralize stomach acid.
- Tablet and Capsule Disintegrant: Helps tablets and capsules break down in the digestive system.
- Tablet Binder: Helps to hold the ingredients of a tablet together.
- Suspending Agent: Used in liquid medications to keep insoluble drugs dispersed.
- Absorbent: Can be used as an absorbent in certain pharmaceutical formulations.
- Other Industrial Applications:
- Ceramics: Used in some ceramic applications.
- Paints and Coatings: Can act as a thickener and suspending agent.
