Vertical roller mill absolute advantage in the international cement raw material grinding areas

 Ball mill market is mainly concentrated in the cement industry. The grinding operation of modern cement industry, including the raw material grinding, cement grinding, slag grinding  and coal powder preparation; to produce 1 ton of cement would need nearly 3 tons of materials; power consumption for grinding operations substantially more than two thirds of the cement integrated power consumption, namely 65 ~ 75kW h / t. Although the power consumption figures with the previous 20 to 30 years, has fallen by about 30%, but continue to innovate, develop new technology, new equipment, and constantly improve grinding efficiency, reduce the grinding power consumption is still relentless pursuit of the cement workers important goal.

The grinding operation of the cement industry in the last 20 to 30 years experienced significant technological progress. In terms of raw material grinding, vertical roller mill has been almost completely replaced the ball (tube) mill, enjoy a wide range of absolute dominance; in terms of cement and slag grinding, a simple ball (tube) mill system has been less used, vertical roller mill is a lot to promote the use of being; in recent years in the developed world market share of more than 70%, to coexist with the (remaining 20% more) is a roller press grinding or semi-final finish grinding system; in coal preparation, vertical roller mill adoption rate is quite high. If we say, 10 years ago, the cement industry is a variety of grinding equipment flowers in full bloom, flourish era, such as roller presses, roller mill, vertical roller mill, etc., are intended to reform fundamentally the ball mill grinding efficiency is too low malpractice and developed a new grinding equipment, industrial practice and then after nearly 10 years of technological competition test, vertical roller mill has finally come to the fore, almost forming a domination.

Throughout the cement industry raw material grinding technology and equipment development process, vertical roller mill after 20 years of practice and improvement, has been able to replace the dominance of milling, and in various other newly developed grinding equipment competition ultimately invincible, which is a main reason that it benefited from NSP cement firing technique to lay the absolute advantage of the position, or is it just well adapted to dry kiln development needs, complemented by ground and common development, complement each other. Its main advantages are:
 1. Restricted use of local material bed crushing principle, to improve the grinding efficiency.
 2. Strong ventilation drying capacity.
 3. Saving electrical energy consumption broken.
 4. Small operation running noise.
 5. Focus broken, grinding, drying, separator and pneumatic conveying of five operations in one unit.
 6. Short material residence time in the mill.
 7. Strong performance of a variety of raw materials adaptability.
 8. Metal wear less.
 9. System less air leakage.
 10. Cement equipment to adapt to large-scale deals.

 The development of things is having a dual character. More of these advantages are clearly not inherent in vertical roller mill, it should be said that some of the original flaws, it is through continuous efforts to improve, to overcome some major flaws before been translated into advantages. In fact, the development of roll mill been confused with the four difficulties, namely wear and life of wear parts, roller mill vibration on hard or quartz feedstock availability, and hydraulic systems, lubrication system, roller bearing with disc reliability. After nearly 20 years of unremitting efforts, with new achievements in materials science, mechanical design and manufacturing, today finally solve these problems, only to vertical roller mill dominant.

 According to incomplete statistics, between 1990 and 2000, the foreign raw mill of system's advanced 2000 ~ 10000t / d new dry process cement production line of about 180 units (sets), of which more than 95% using the vertical roller mill, the remaining several raw material grinding roller press is used finish grinding systems and roller mill system, and the use of closed-circuit tube mill actually one did not. And the kiln system production ≤6000t / d, and are used in a kiln with a vertical roller mill design patterns. It can be seen in the vertical roller mill raw material grinding in the field of international cement industry has an absolute advantage in the traditional circle flow ball (tube) mill as a backward equipment has tended to be eliminated. From a technical development trend, China's situation should be such that the vertical roller mill will inevitably replace the ball (tube) mill, the domestic industry which has already reached a consensus.