Comparison between Overflow Ball Mills and Grid Ball Mills

According  to their different discharging end, ball mills can be divided into three types:  grid type, overflow type and peripheral discharge type. In practice, peripheral  discharge ball mills are rarely used; while grid ball mills and overflow ball  mills are commonly adopted. If comparing the grid types and overflow types,  what are the common grounds and differences between them? Under what  circumstances are grid ball mills a better choice? And overflow ball mills?  Here, we will give a brief introduction to you.

Common Grounds:

Overflow  ball mills and grid ball mills have basically the same structure, consisting of  shells, feeding ends, discharging ends, main bearings as well as drive and  lubrication system.

Differences:

Different  structure of Feeding End. The main part of overflow ball mills’ feeding end is helical  blade with the opposite rotation direction to the mills; while that of grid  ball mills is grid plate.

1. Different  Discharging Principles. The grinded ore fines in overflow ball mills overflow  outside with the help of height difference between neck of hollow shafts of  discharging end and feeding end. Meantime, steel balls and the rest ore  particles first settled into bottom of the reversed helical blade and then be  transmitted back to the mills. Overflow ball mills belong to high level ore  discharge. By contrast, the fine-grained particles of grid ball mills are  discharged by grid plate, which belongs to low level ore discharge.

2. Different  Motion State of Steel Balls. Overflow ball mills have lower rotary speed and  their steel balls drop on and on after rising to a certain level, so their acting  force is mainly grinding-based, supplemented by impact power. While grid ball  mills have higher rotary speed and their steel balls are thrown and fallen, so  the acting force is mainly impact, supplemented by grinding.

3. Different  Ball Mills’ Productivity and Grinding Fineness. Compared with grid ball mills  of the same specification, overflow ball mills productivity is lower, about  10% to 15%, but their grinding products are finer.

Grid  ball mills are characteristic of high productivity, high grinding efficiency  and coarser products, which makes themselves commonly used in primary grinding  stage or secondary grinding stage with -200 mess grinding fineness less than  65%. Accordingly, overflow ball mills feature lower productivity and finer  grinding products, widely applied in secondary grinding process. Shandong  Xinhai Mining Technology & Equipment Inc., known at home and abroad, has  supplied various grid ball mills and overflow ball mills with a serious of  advantages, including stable operation, saving energy and cheaper price. Xinhai  has extensively earned new and old customers’ credits so it’s definitely worth  recommendations. 

Tags:Comparison between Overflow Ball Mills and Grid Ball Mills

From:Xinhai Mining Machinery Company