What are the functions in the use of surfactants?

2022-08-22 16:56:48

As a grinding aid, surfactant also plays a lubricating role, which can improve the specific surface area of the product, shorten the grinding time and improve the grinding efficiency. Its action mechanism can be summarized as: reducing crushing energy, increasing brittle fracture probability, preventing plastic deformation, controlling flocculation and aggregation of fine particles, strengthening dispersion and adjusting rheological property of slurry.

Surfactant is a kind of functional fine chemicals. Due to its amphiphilic structure and properties, surfactants self polymerize in solution to form various forms of molecular ordered assemblies, such as micelles, reverse micelles, vesicles, liquid crystals, etc. The particle size or the thickness of the aggregated molecular layer of these molecular ordered assemblies are close to the order of nanometers, which can provide suitable places and conditions for the formation of ultrafine particles with "quantum size effect", and the molecular aggregates themselves may also have similar "quantum size effect".

Therefore, the ordered molecular assembly of surfactant shows various practical functions, such as emulsification, solubilization, wetting, adsorption, penetration, dispersion, defoaming, thickening and lubrication. It is used as printing and dyeing auxiliaries, pesticide emulsifiers, dispersants for emulsion polymerization of polymer materials, and can also be widely used in mining, petroleum, lotion polymerization and other industries.

At the same time, the application in colloidal rheology, microemulsion and liquid crystal template has also attracted people's attention. In recent years, surfactants have played a very important role and played an outstanding role in the preparation of inorganic materials, ultrafine powders, nano and nano composite materials, molecular sieves and porous materials.

The addition of grinding aids can significantly improve the crushing efficiency of minerals and reduce energy consumption. There are two mechanisms: ① rehbinder's theory of "adsorption reduces hardness". The surface active agent can promote the deformation or destruction of the surface by adsorbing on the structural defects on the surface of mineral solid particles. That is, the adsorption of the grinding aid molecules on the particles reduces the surface free energy of the particles or causes dislocation migration of the surface lattice, resulting in point defects or line defects, thus reducing the strength and hardness of the particles and promoting the generation and expansion of cracks. ② Klmpel's theory of "pulp rheology regulation" holds that grinding aids regulate the rheological properties of the slurry and the surface electrical properties of the particles, reduce the viscosity of the slurry, promote the dispersion of the particles, improve the fluidity of the slurry, and control the agglomeration and adhesion between the particles, the particles and the grinding medium and the lining plate.