Bentonite is a non-metallic mineral mainly composed of montmorillonite. The montmorillonite structure is a 2:1 type crystal structure composed of two silica tetrahedra sandwiched with a layer of aluminum oxide octahedra. Due to the layered structure formed by montmorillonite crystal cells, there are certain cations, such as Cu, Mg, Na, K, etc., and their interaction with montmorillonite crystal cells is very unstable, which is easy to be exchanged by other cations, so they have good ion exchange properties. Abroad, it has been applied in more than 100 departments in 24 fields of industrial and agricultural production, with over 300 products, hence people call it “universal soil”.

Bentonite is also known as bentonite, bentonite, or bentonite. China has a long history of developing and using bentonite, which was originally only used as a detergent. There were open-pit mines in the Renshou area of Sichuan hundreds of years ago, and the locals referred to bentonite as clay powder. It is truly widely used but only has a history of over a hundred years. The earliest discovery in the United States was in the ancient strata of Wyoming, where yellow green clay, which can expand into a paste after adding water, was commonly referred to as bentonite. In fact, the main mineral component of bentonite is montmorillonite, with a content of 85-90%. Some properties of bentonite are also determined by montmorillonite. Montmorillonite can appear in various colors such as yellow green, yellow white, gray, white, and so on. It can form dense blocks or loose soil, with a slippery feeling when rubbed with fingers. After adding water, the volume of small blocks expands several times to 20-30 times, appearing in a suspended state in water, and in a paste state when there is little water. The properties of montmorillonite are related to its chemical composition and internal structure.

Activated clay

Activated clay is an adsorbent made from clay (mainly bentonite) as raw material, which is subjected to inorganic acidification treatment, followed by water rinsing and drying. Its appearance is milky white powder, odorless, tasteless, non-toxic, and has strong adsorption performance. It can adsorb colored and organic substances. It is easy to absorb moisture in the air, and placing it for too long will reduce the adsorption performance. However, heating to above 300 degrees Celsius begins to lose crystalline water, causing structural changes and affecting the fading effect. Activated clay is insoluble in water, organic solvents, and various oils, almost completely soluble in hot caustic soda and hydrochloric acid, with a relative density of 2.3-2.5, and minimal swelling in water and oil.

Natural bleached soil

The naturally occurring white clay with inherent bleaching properties is a white, white gray clay mainly composed of montmorillonite, albite, and quartz, and is a type of bentonite.
Mainly the product of the decomposition of glassy volcanic rocks, which do not expand after absorbing water, and the pH value of the suspension is different from that of alkaline bentonite; Its bleaching performance is worse than that of activated clay. The colors generally include light yellow, green white, gray, olive color, brown, milk white, peach red, blue, etc. There are very few pure white ones. Density 2.7-2.9g/cm. The apparent density is often low due to its porosity. The chemical composition is similar to that of ordinary clay, with the main chemical components being aluminum oxide, silicon dioxide, water, and a small amount of iron, magnesium, calcium, etc. No plasticity, with high adsorption capacity. Due to its high content of hydrous silicic acid, it is acidic to litmus. Water is prone to cracking and has a high water content. Generally, the finer the fineness, the higher the decolorization power.

Bentonite ore
Bentonite ore is a mineral with multiple uses, and its quality.