Views: 4 Author: su Publish Time: 2018-11-16 Origin: Site
The cement industry is a high-energy-consuming industry, and the energy consumption in the cement grinding process accounts for a large proportion in the whole production process, of which electricity consumption accounts for 60%-70%, and its energy utilization rate is extremely low. About 97% of the energy consumed in the grinding process becomes a waste of heat, and only a small part of the energy increases the surface area of the material, in order to reduce energy consumption, save energy, and improve grinding efficiency.
It is one of the most effective methods to add a small amount of grinding aid to the grinding process to improve the grinding efficiency. With the wide application of cement grinding aids in cement production, the development of cement grinding aids in China has also made certain progress and achievements. At present, domestic research and application of cement grinding aids are liquid and solid. The formula consists mainly of amines, polyols, acetates, etc. The basic components are mostly organic surface active substances. Triethanolamine and ethylene glycol are highly polar surfactants.
Triisopropanolamine and diethanol monoisopropanolamine are used as cement grinding aids, but they have the disadvantages of high price and shortage of sources. Compared with triethanolamine, triisopropanolamine has many advantages in terms of dispersibility, age enhancement, application conditions and price.
The standard consistency of the grinding aid is closely related to the water content of the cement and the dispersion of the grinding aid. When the fineness of the cement is increased, the specific surface area of the particle group is increased, and the minimum water consumption required to coat the surface of the particle is increased, so that the water content of the standard consistency is increased, and at the same time, the agglomeration of the fine particles also envelops a part of the water, making it impossible to Play the role it deserves. However, the grinding aids are generally strong adsorption, highly dispersed surface active substances, which can be adsorbed on the surface of the cement particles, effectively destroy the agglomerated structure, increase the "effective water", and the electrostatic repulsion between the particles will weaken the interaction. The use of water is reduced and the fluidity is improved.
The early and strong components of the composite grinding aid promote the hydration of the cement, forming more early hydration products, making the slurry structure dense and improving the strength; on the other hand, the early strength of the composite grinding aid depends on the improvement At the hydration rate, the addition of the grinding aid increases the fineness of the cement. Under the condition that the composition and structure of the cement mineral are unchanged, the improvement of the fineness is an important guarantee for accelerating the hydration. However, if the fluidity of the slurry is thus reduced, in order to ensure the normal fluidity and increase the amount of molding water, the porosity of the slurry is bound to increase. Many studies have shown that the strength of the slurry decreases exponentially with the increase of porosity. It is impossible to increase the strength.Triethanolamine, ethylene glycol and triisopropanolamine can increase the specific surface area of cement and improve the gradation of cement particles according to the proper ratio. The cement grinding aid can not only improve the grinding efficiency of cement, but also has obvious reinforcing effect. Especially early strength can be increased by about 17%. The enhancement of the grinding aid is mainly due to the beneficial early strength component of the composite grinding aid promoting the hydration of the cement, making the cement slurry dense and strong.