Based on adopting the technology of CK mill & CKP mill from Germany & Japan, in accordance with that the power consumption of grinding system in local & foreign market mainly shown on the section of raw powder manufacturing, coal powder manufacturing and cement grinding, successfully researched and developed the latest generation of pre-grinding equipment CKP vertical roller mill which could highly improved the production with extreme low power consumption. The technical innovation of energy-saving & consumption-reduction on grinding system enjoyed special state acid, and the potential of energy-saving on grinding system is quite large as there are about 5100 grinding enterprise with quite scale in local market.
In order to search for the method for production-improving & energy-saving of ball mill, via years of scientific experiments and producing experiences, local operator of grinding system developed the pre-grinding process which reduce the inlet grain size with more to be crushed and less to be grinded, so the production of mill has been improved meanwhile the power consumption decreased, that is to say that the inlet grain size has been reduced to 3mm, the working for first chamber of ball mill has been moved out of mill and be finished by crusher, while the efficiency of crusher could reach 25% - 40%.
CKP vertical roller mill is: three symmetrical rotating roller will rotate comply with disc to cut, extrude and grinding the material on disc with the function of high pressure, its special roller shape design and material layer grinding technology, greatly reduced power consumption for each unit and it is widely used for material grinding process in building material, metallurgical, chemical industries, etc. While it could be utilized together with ball mill to be circular pre-grinding, circular classifying & pre-grinding and final grinding system. Integrative grinding power consumption decreased 30% - 50%, while the production increased 50% - 100% which implements the target of energy saving, emission reduction, high production & low consumption of high efficient grinding, and it has really high economical and social benefit. CKP vertical roller mill is mainly composed of motor, reducer, disc, roller, hydraulic device, lubricating device, etc. Material will enter into centre of disc via feeding chute, then they will be thrown into grinding area with the function of centrifugal force caused by the rotating of disc and material will be extruded and grinded by pressed roller. Grinded material will fall into the lower part of cover via outer section of disc, then they will enter into discharging chute by scraper and be discharged. The characters of this system:
1.Roller utilizes forced lubricating oil feeding type to efficiently avoid powder entering into bearing and utilizes double sealing mechanism of forces venting air seal and reinforced seal.
2. Liner of disc and surface of roller utilize high-chromium iron with longer useful life (＞30000Hr), and it is easy to change.
3. Reducer utilizes hydrostatic lubricating system, utilizes sensor to monitor the oil pressure and oil temperature of thrust bush to ensure the stability of operation.
4. Hydraulic oil station utilizes batch & following working method, configures advanced following monitoring elements to have continuous and uninterrupted check on the operating status of equipment, improves the system operating condition and extends the useful life of elements.
5. Improve production and reduce consumption and the effect is obvious. Utilizing this equipment for grinding process implements that the new grinding technology with extruding and cutting force is widely promoted, which has better grinding effect compared to current roller presser. And the cement raw material grinding capacity could increase 100%, cement clinker producing capacity could increase 50% while power consumption could decrease 30% - 40%， and it formed the grinding system with ball mill which makes the regulating range of product fineness wider and the cement compressive strength obviously be improved.
Cement grinding utilizes pre-grinding process which is widely used in new type dry process production line; it has become the trend of new set-up factory or old-factory technical improvement and the pre-grinding equipment mainly is roller presser and vertical roller mill (roller mill). From the angle of power utilization rate, roller presser is a little bit higher than that of vertical roller mill, but from the angle of operation stability and adoptability on feeding grain size, vertical roller mill is better than roller presser. Seeing from the local utilization, whatever roller presser or CKP vertical roller mill is used for pre-grinding equipment, both could gain the effect of production improvement and energy-saving, the improved production could reaches 33%-100%. However, the maintenance of roller pressure is a little more different, the abrasive cycle of roller surface is about 6000hours, after that, it should be dis-assembled for re-bead welded for repairing. While operation of CKP is high, life cycle of roller surface could reach over 30000 hours, thus maintenance is less. The grinding efficiency is affected by many factors, including grinder graduation, mill venting, clinker temperature and grinding process, etc. meanwhile it should also consider utilizing the closed-circuit ball mill process configuring high efficient separator, as closed-circuit mill is good for adjusting and controlling the fineness and temperature of product, grinding efficiency is 10%-20% higher than that of open-circuit mill, and the finer of finished product, the more obvious of effect.
