Cement quality requirement put a higher demand on vertical roller mill separator
On the one hand, the cement user has increased their demand on cement quality. There is the trend towards high fineness, the development of high-grade cement, while the high fineness of cement production, open or closed circuit grinding system grinding of vertical roller mill with conventional separator, is a very difficult job.
On the other hand, people have further and deeper recognition on cement quality, making quality cement in the evaluation of some of the points changed. Initially, as the cement fineness of cement quality is one of the main indicators of sieve residue control, with the sieve residue control can only reflect the number of coarse particles in the finished product, and does not reflect the situation of all particle thickness; then developed to control the specific surface area of ??cement The finer, the greater surface area. Now, we find that even the same surface area of ??cement products, due to the use of the vertical roller mill grinding process, the different ways separator, its strength is also a difference. Closed-circuit vertical roller mill grinding with high efficiency separator can be lower, owing to the different particle size distribution.
Studies have shown that the thickness of the cement particles composed of particles of different properties of cement hydration effect is different. Particles larger than 60μm little effect on the strength of the cement, only play the role of filler; hydration process is less than 3μm particles have been completed in the early hardening only beneficial for the early strength cement; 3-30μm particles is the main active part cement, bear the primary particle size of the strength of growth. In response, some varieties of cement particles 3-30μm had made specific content requirements:
Ordinary Portland Cement: 40-50%
High strength and rapid hardening cement: 50-60%
Ultra-strong rapid hardening cement:> 70%
Thus, the quality of cement has a great relationship. In the cement grinding operations with cement products content 3-30μm particles, to get a high content of particle size range, a relatively narrow distribution of cement products, only through efficient vertical roller mill classifier to regulate, control, otherwise it is difficult to achieve.
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