Roll Grinder Research Articles

Exploring the ultrasonic comminution of copper ores

This paper presents grinding results obtained with a Chilean porphyry copper ore in the ultrasonic nip roll grinder of the US Comminution Center. Comparison with ball milling is performed by scaling-down industrial ball mill behavior to the ultrasonic grinding conditions. For small gap setting in the ultrasonic device, size distribution and specific energy consumption are in the same order of magnitude for both alternatives, but for larger openings in this ultrasonic prototype, the ball mill is much more efficient. Current design of the ultrasonic device is analysed and reasons why oversize and undersize particles are not well fractured are discussed. In spite of the current limitations, it is concluded that there is great potential to improve its performance.

Development of On-line Roll Grinding System for Hot Strip Mill.

Schedule Free-Rolling (SFR), which means rolling with unrestricted rolling schedules in the processing of strips of various materials and widths, should be developed to realize hot-charge-rolling and hot-direct-rolling whose importance has been increasing in hot strip rolling mills. As a technique to make SFR practical, we have developed a non-driven cup type On-line Roll Grinder (ORG) which smooths the wear of a work roll on line. Our experiments have proven that the ORG has the basic capabilities required for an on-line roll grinder: high grinding capacity, long grinding wheel life and appropriate roughness of the finished surface. In addition, the ORG is free of welding and dulling and maintains stable grinding characteristics for a long time. We have also developed an on-line roll grinding system equipped with an On-line roll Profile Meter which can measure the profile of a revolving roll without contact. The data taken by these profile meters is fed back to the ORG, thereby increasing its grinding accuracy and allowing it to grind a roll to the required profile.