Halloysite powder is a naturally occurring clay mineral powder derived from halloysite, a hydrated aluminum silicate with a chemical formula of Al₂Si₂O₅(OH)₄·nH₂O. It is formed through the hydrothermal alteration of aluminum-rich rocks, such as volcanic ash and feldspar, under specific geological conditions over long periods.
The extraction process begins with the mining of halloysite-containing ore from deposits located in regions like China, the United States, and New Zealand. Once mined, the ore is crushed and ground into smaller particles. Then, through processes such as wet or dry sieving, magnetic separation, and flotation, impurities are removed to obtain high-purity halloysite powder. The powder typically features a unique tubular structure, with diameters ranging from 20 to 100 nanometers and lengths from 0.5 to 2 micrometers.
Chemically and physically, halloysite powder stands out for its high surface area, cation exchange capacity, and thermal stability. These properties make it highly versatile. In the field of nanocomposites, it acts as a reinforcing filler, enhancing the mechanical, thermal, and barrier properties of polymers used in automotive parts and packaging materials. As a carrier in the pharmaceutical and cosmetics industries, its hollow structure can encapsulate active ingredients, enabling controlled release. In environmental applications, it adsorbs heavy metals and organic pollutants, aiding in water purification and soil remediation. Additionally, halloysite powder serves as a catalyst support and a functional additive in paints and coatings, improving durability and weather resistance.
