The combined grinding of the vertical roller mill and the ball mill is a new grinding process in which the vertical roller mill is connected in series with the ball mill. The vertical roller mill first pre-grinds the clinker and the mixed material. After the clinker is pre-grinded, the mill is set to be inclined. The inner screening device, the escaped bulk material is blocked by the screening device, and returned to the vertical roller mill for grinding and grinding.
The smaller material passes through the sieve, and the fine powder after the screening enters the ball mill; the material is crushed and sheared and pulverized, the particle size becomes very small, and there are many cracks, of which 30% is less than 80um, and the mixture enters the ball mill. In the future, the ball mill is made with good grinding conditions; the top of the vertical roller mill is designed as an O-Sepa separator with a small air inlet, and the powdered layer on the vertical grinding disc is reduced by strong ventilation, and the powder is qualified after the powder selection. The material enters the finished product warehouse, and the coarser material enters the mill to continue grinding, and the material is secondly ground by the ball mill, such as the finished product warehouse.
The process characteristics of the combined grinding process are mainly as follows:
1) The vertical roller mill first pre-grinds the clinker. After the clinker is pre-grinded, the granules are rolled and sheared, and there are many cracks. After the mixture enters the ball mill, it produces a good grinding condition for the ball mill, which greatly improves the system grinding ability.
2) The vertical roller mill adopts a static and dynamic ring to ensure the thickness of the layer.
3) According to the characteristics of the grinding efficiency, the gap of the sieve can be conveniently selected to determine the particle size entering the ball mill, thereby increasing the output of the ball mill.
4) The sorting system is different from the ordinary high-fine grinding screen. The main difference is: it belongs to dynamic active sorting, the sorting efficiency and precision are higher, the adjustment is convenient and reliable, and the ventilation area inside the mill is not affected.
5) This combined grinding makes the cement particle size distribution and particle morphology tend to be reasonable, solves the key common technical problems of particle characteristics and surface energy, mechanical energy and chemical energy, and greatly improves the gelation efficiency. The mechanical energy activation of siliceous, silico-aluminum industrial solid waste is combined with chemical energy activation.
Milling equipment is an important machine equipment in cement production. The energy consumption of traditional milling equipment accounts for more than 70% of the total electricity consumption in total energy consumption. Therefore, the improvement of existing equipment is imperative. The combination of ball mills and vertical roller mills will inevitably promote the vigorous development of the cement industry.