5. Results and discussion
The results showed that limestone-I sample was more friable than limestone-II sample while limestone-II sample was more friable than limestone-III sample. A set of t-curves were calculated from the direct a laboratory impact mill and a new size distribution equation was developed.
The product size distribution from the breakage by impact crusher of particle can be described as all-parameter (tn) family of curves. The product size distributions were found to be normalizable with respect to particle sizes. Cumulative percentages of passing material belong to (tn) the experimental data was compared with the proposed equation given a better results with data and has a potential use in industrial applications.
In this study, the type of limestone has emerged very clearly played an important role in comminution. In addition, in crusher selection was played an important role of the standard the Bond grindability and work index values.
The t-curves are the family of size distribution curves which can be used to describe the product size distribution of the breakage particles during single-particle breakage tests. The cumulative percentages passing of the parameters t2, t4, t10, t25, t50 and t75 are determined by linear interpolation from the breakage products passing against the different range of sieve sizes. However, there are many difficulties and problems in drop weight and twin pendulum test methods such as being laborious, requiring long test time and requiring a special apparatus.
This paper presents the results of an investigation into the effects of the Bond work index and the mean particle size on particle size distribution in a pilot scale impact mill. The results denote that particle size distribution is strongly related to mean particle size (X) and Bond work index (Wi). The relationship with data from experimental and proposed equation for determination of particle size distributions has emerged by a high regression value
(r2 = 0.88).
6. Conclusions
In this study, laboratory crushing tests of three different limestones with an impact crusher were carried out. The effects of mean particle size and Bond work index of limestones on product size distribution were investigated.
The proposed model equation which incorporates the selfsimilar breakage behaviour in laboratory comminution could be used an alternative to the drop weight and twin pendulum tests, as its particle size distributions could evaluated more readily and reliably.
There are no studies in the literature which have been made about the effect of the amount of feed, effect of rotor speed, lining design and design of the hammer on the impact crushers, very commonly used in quarries. Therefore, crusher and grinder manufactures will be possible to make appropriate choices of such studies with different designs for different material to be developing similar models.
This study showed that product size distribution could be different for different material properties. Therefore, it appears that the particle size distributions of each material in crushing process must be evaluated in order to lower the energy costs.
References
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