010E-079 1/2 Alumina Balls, HD, 010E-198 1/4 SS Balls, 010E-197 1/2 SS Balls, 010E-196 5/8 SS Balls, 010E-195 3/4 SS Balls, 010E-095 1/4 Grinding Balls, 010E-094 1/2 Grinding Balls, 010E-093 3/4 Grinding Balls, 010E-092 2 Grinding Balls, 010E-090 1-1/2 Grinding Balls, 010E-089 1-1/4 Grinding Balls, 010E-088 1 Chrome Steel Balls, 010E-087 7/8 Grinding Balls, 010E-086 1/2 Zirconia Grinding, 010E-082 1-1/4 Alumina Balls, HD, 010E-081 1 Alumina Balls, HD, 010E-080 3/4 Alumina Balls, HD, 010E-199 1-7/16 Grinding Balls, Chrome
Sepor, Inc. began business in 1953 with the introduction of the Sepor Microsplitter , a Jones-type Riffle splitter, developed by geologist Oreste Ernie Alessio for his own use in the lab. Sepor grew over the next several decades to offer a complete line of mineral analysis tools, as well as pilot plant equipment for scaled operations.
A) Total Apparent Volumetric Charge Filling including balls and excess slurry on top of the ball charge, plus the interstitial voids in between the balls expressed as a percentage of the net internal mill volume (inside liners).
B) Overflow Discharge Mills operating at low ball fillings slurry may accumulate on top of the ball charge; causing, the Total Charge Filling Level to be higher than the Ball Filling Level. Grate Discharge mills will not face this issue.
C) This value represents the Volumetric Fractional Filling of the Voids in between the balls by the retained slurry in the mill charge. As defined, this value should never exceed 100%, but in some cases particularly in Grate Discharge Mills it could be lower than 100%. Note that this interstitial slurry does not include the overfilling slurry derived from the difference between the Charge and Ball Filling.
D) Represents the so-called Dynamic Angle of Repose (or Lift Angle) adopted during steady operation by the top surface of the mill charge (the kidney) with respect to the horizontal. A reasonable default value for this angle is 32, but may be easily tuned to specific applications against any available actual power data.
The first step in mill design is to determine the power needed to produce the desired grind in the chosen ore. The most used equation, for this purpose, is the empirical Bond equation (Bond, 1960, 1961; Rowland and Kjos, 1978).
In this equation, E is the specific energy required for the grind, and F80 and P80 are the sizes in micrometers that 80% of the weight passes of the mill feed and product respectively. The parameter Wi, known as the work index of the ore, is obtained from batch bench tests first devised by Bond (1961). The power calculated on using equation 1, (Bond, 1961; Rowland and Kjos, 1978), relates to:
1) Rod milling a rod mill with a diameter of 2.44 meters, inside new liners, grinding wet in open circuit. 2) Ball milling a ball mill with a diameter of 2.44 meters, inside new liners, grinding wet in open circuit.
When the grinding conditions differ from these specified conditions, efficiency factors (Rowland and Kjos, 1978) have to be used in conjunction with equation 1. In general, therefore, the required mill power is calculated using the following equation
where n is the number of efficiency factors, EFi, used and fo is the feed rate of new ore to the mill. The power calculated from equation 2 can be looked up in published tables (Rowland and Kjos, 1978) and the correct mill size and type can be selected.
The philosophy in the development of the MRRC grinding simulation package was to build interactive software that could be used as an inexpensive means of providing a semi-quantitative check on a grinding mill design. In addition the software is designed to slot in to a general mineral processing package now undergoing development at the MRRC.
The need to improve the technology associated with traditional methods of crushing and grinding has been an undisputed area of debate. Yet, there is very little structural and design improvement for increased capacity and energy utilization of the mill. This paper discusses the results of some of the design and test work done on a cascading type mill that is a modification of a ball mill. Basically, the cascading mill is designed to operate at super critical speeds but the charge is restricted to move in a cascading manner. Thus the number and intensity of collisions per unit time is increased. Results of laboratory experiments show that the cascading mill performs better than a ball mill.