Bleaching Earth

Bleaching Earth, also known as fuller’s earth or activated clay, is a highly adsorptive material used in the refining and purification of fats, oils, and other liquids. Its primary function is to remove colour, impurities, and contaminants from these substances, improving their quality and appearance. Bleaching earth plays a critical role in the oil refining industry, particularly for edible oils such as palm oil, soybean oil, and sunflower oil, as well as in the purification of petroleum and other chemical products.

Composition and Types

Bleaching earth is primarily composed of naturally occurring clay minerals, most commonly bentonite or attapulgite, which are rich in montmorillonite. Montmorillonite is a layered alumino-silicate mineral that provides the clay with its high surface area and ion-exchange capacity, making it ideal for adsorption processes.

There are two main types of bleaching earth based on how they are processed:

Natural Bleaching Earth

Derived from unmodified clays that are naturally adsorptive. These clays are milled and sieved to achieve a desired particle size distribution.

Activated Bleaching Earth

This type is treated with acid, typically sulfuric acid, to enhance its adsorptive properties by increasing surface area, pore size, and the number of active sites. Acid activation removes impurities and makes the clay more porous, boosting its decolorization efficiency.

Applications

Bleaching earth is widely used in industries that require the decolorization and purification of various oils and liquids.
The primary applications include:

Edible Oil Refining:

Bleaching earth is used in the refining process of vegetable oils (e.g., soybean, palm, sunflower) to remove pigments (chlorophyll, carotenoids), residual soap, phospholipids, and other contaminants. This improves the colour, flavour, and oxidative stability of the oils. 

Oil Refining Process:

After degumming and neutralization, the oil is mixed with bleaching earth and heated under vacuum. The contaminants are adsorbed onto the surface of the clay and then filtered out, leaving behind clear, purified oil.

Animal Fats and Fish Oils:

Bleaching earth helps to decolorize and purify fats and oils derived from animal sources, making them suitable for food and industrial use.

Petroleum and Mineral Oil Refining:

Used to remove impurities, sulfur, and trace metals from lubricating oils, diesel, and other petroleum fractions.

Cosmetics and Pharmaceuticals:

In the cosmetics and pharmaceutical industries, bleaching earth is used to refine raw materials by removing coloured impurities and unwanted byproducts.

Biodiesel Production:

Plays a role in purifying biodiesel by adsorbing residual soap, catalysts, and colour bodies, improving the quality of the final product.

Partnering with regional manufacturers with state of the art facilities, we supply products which are high quality and food grade certified to meet your requirements.