International Journal of Emerging Technology and Advanced Engineering Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 4, Issue 2, February 2014) 592 Simulation studies on Energy Requirement, Work Input and Grindability of Ball Mill Abanti Sahoo Chemical Engg. Dept., National Institute of Technology, Rourkela-769008,Odisha, India Abstract— Energy requirement, work input and grindability of ball mill have been studied by varying different system parameters (viz. particle size & density of materials, number of balls, time of grinding and speed of the mill). Attempt has also been made to correlate the output with these inputs on the basis of regression analysis. Different C ++ programmings were written to compute energy requirement, work input and grindability for the ball mill using the above mentioned system parameters. Finally a comparison has been made among experimentally observed values and the values determined by other methods (i.e. C ++ programming, and regression analysis). For comparing the goodness of the fit, the correlation coefficient and chi-square test have been used. Keywords — Comminution, Bond’s Work Index, Grindability, Dimensional analysis approach, C ++ programming, correlation coefficient and Chi-square test. I. INTRODUCTION Grinding is one of the most energy-intensive operations in the preparation of ores and has a significant effect on the economics of processing these raw materials. Therefore it becomes especially important to select the correct equipment for this operation. The choice of equipment chosen for the comminution of ore is mainly based on the Bond work index, which is usually determined by the standard method of dry grinding. Traditional measurements of ore grindability are the Bond Work Index. The Bond test is still surprisingly popular, despite the advances in modelling and computing power. Grindability data, based on various techniques to measure comminution characteristics, are used to evaluate the crushing and grinding efficiency in mineral processing operations. The importance of achieving improved comminution efficiency, in terms of energy consumption, has been emphasized by increase in the cost of electricity (Horst and Bassarear, 1976). Bond’s grindability can be empirically related to the energy required for comminution and thus is useful for the design and selection of crushing and grinding equipment (Deniz et al., 1996). Ball milling is a wide spread milling technology, particularly in mining; mainly because of its simple construction and application. The Bond grindability testing procedure has been standardized to obtain the grindability values (i.e., Bond work index (BWi)) on the same ore when tests are performed in different laboratories or by different operators. The results for the Bond work index grindability thus obtained may differ substantially with different standard Bond ball mills (Kaya et al., 2003). Therefore there is need for development of a more general and standard model to measure the performance of the ball mill. II. PREVIOUS WORK Comminution in a mineral processing plant or, mill involves a sequence of crushing and. grinding processes (Prasher, C.L., 1987). Literature on impact crusher performance in relation to machine configuration and operational conditions, by experimental work and mathematical modelling is given by Austin et al. (1979) and Shi et al.(2003). The Bond grindability test has been widely used for predictions of ball and rod mill energy requirements and for selection of plant scale comminution equipment (Babu and Cook,1973). It is known that the efficiency of the mill can be increased by tuning the rotation velocity so that the average collision velocity becomes maximum. In this context attempt has been made for a meticulous study for the effect of the various system parameters on the performance of ball mills. If the peripheral speed of the mill is very high, it begins to act like a centrifuge and the balls do not fall back, but stay on the perimeter of the mill and that point is called the "Critical Speed‖ (McCabe et al., 1993). Ball mills usually operate at 65% to 75% of the critical speed and this is calculated as under. r R g 2 1 n c    (1) Grindability (G): Grindability is the number of net grams of screen undersized product per revolution (Perry and Chilton, 1973). The main purpose of study of the grindability is to evaluate the size and type of mill needed to produce a specified tonnage of product and thereby the power requirement for grinding.