Bentonite is divided into sodium based bentonite, calcium based bentonite, magnesium based bentonite, and aluminum (hydrogen) based bentonite according to the type and content of exchangeable cations between the layers of montmorillonite. The interlayer domain of bentonite is the distance between its structural layers. Because interlayer domains have the advantages of interlayer exchange, interlayer polymerization, interlayer pillaring, and interlayer adsorption, they are used as environmental adsorption materials. The classification of bentonite is determined by the type and amount of interlayer cations. If the interlayer is mainly composed of sodium ions, the bentonite belongs to sodium based bentonite; If the interlayer is mainly composed of calcium ions, the bentonite belongs to calcium based bentonite. The type of bentonite determines its layer spacing, which is generally 0.96~2.14 nm for bentonite layers, and about 15 nm for calcium based bentonite layers; The interlayer spacing of sodium based bentonite is approximately 1.2 nm.
In recent years, the preparation of functional materials by adjusting the interlayer spacing and changing the properties of bentonite through pillaring, ion exchange, and other methods has become a research hotspot in various fields.
Sodium based bentonite uses bauxite and talc powder as refractory aggregates, sodium based bentonite and CMC as composite suspension agents, sodium hexametaphosphate and water glass as binders, and water as the carrier, with an appropriate amount of defoamer and surfactant added. The addition amount of CMC is 0.5%, water glass is 5%, and sodium hexametaphosphate is 6% (the addition amount of each component is the mass fraction of the refractory aggregate). Change the amount of sodium based bentonite added, test the density, pH value, viscosity, suspension, leveling, coating amount, drip mobility, and strength of the coating, and study the impact of sodium based bentonite on the performance of the coating.
The experiment found that the coating had the best comprehensive performance when the addition amount of sodium based bentonite was 5%.
Post time: Mar-27-2023