LITERATURE REVIEW THE EFFECT OF PARTICLE SIZE DISTRIBUTION ON PACKING DENSITY, WITH RELATION TO IRON ORE

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PARTICLE SIZE DISTRIBUTIONS (PSD)
There are several mathematical distributions used for PSD’s, the 2 main distributions are Gaussian and Log-Normal. The Gaussian distribution is less common, and due to the fact that it is plotted with a regular scale it is asymmetrical. The Log-Normal distribution is plotted on a log x axis, hence this makes it more symmetrical and easier to read. Another distribution is a multimodal distribution, which has more than 1 maximum. 5
A study was done that compares the 2 distributions, with regards to the packing densities. 1 The results show that as the dimensionless standard deviation (σ/x̄) increases, the packing density increases as well. The only exception is when σ/x̄ < 0.1. The mean particle size has no significant effect on the packing density.
There is a small difference in the packing density for the 2 distributions, and the log-normal system has a higher packing density than the Gaussian system.1
There are certain properties of a PSD that may influence the packing density. The characteristic s that has the most influence on RCP is the skew of the distribution and polydispersity. Polydispersity is when the particles are not the same size, shape and mass.

Figure 1: A diagram showing the two extreme forms of skewness.4
For a negative skew, shown in figure 1, the effect of polydispersity does not have as much of an effect on the packing density as the positive skew. A negative skew, larger proportion of large particles, will have most of the volume occupied by the larger particles. This means the particles pack like a monodisperse sample.3
The positive skew, larger proportion of small particles, results in an increase of packing density. This is due to the small particles being able to fi...

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...DF] Sydney: Colloidal Dynamics; 1999. Available from: http://www.colloidal-dynamics.com/docs/CDElTut2.pdf.

6. Kwan A, Chan K, Wong V. A 3-parameter particle packing model incorporating the wedging effect. Powder Technology. 2013;.

7. Rassouly S. The packing density of ‘perfect’ binary mixtures. Powder Technology. 1998; 103 (2): 145-150. Available from: http://www.sciencedirect.com/science/article/pii/S003259109800223X [Accessed 10 February 2014].

8. Webb M, Davis I. Random particle packing with large particle size variations using reduced-dimension algorithms. Powder technology. 2006; 167 (1): 10--19.

9. Yu A, St, Ish N. An analytical—parametric theory of the random packing of particles. Powder technology. 1988; 55 (3): 171--186.

10. Yu A, St, Ish N. A study of the packing of particles with a mixture size distribution. Powder technology. 1993; 76 (2): 113--124.

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