Influence of slurry rheology on stirred media milling of quartzite

The role of slurry rheology in stirred media milling of quartzite has been investigated by varying important grinding parameters such as media bead density and size, addition of chemicals, solids concentration, stirrer rotational speed as well as the combined effect of these factors. Media bead density has an evident but complex effect on stirred milling performance, depending on stirrer rotational speed and solids concentration. The effect of media bead size on the ultra-fine grinding of quartzite is relevant to the feed size. Optimal ratio of media bead size to the median size of a feed is between 150 and 200. The combined effect of grinding bead size and stirrer speed or solids concentration is insignificant. The addition of Dispersant S40 or a lower solids concentration results in better grinding performance (i.e., a higher energy efficiency and a smaller median size) due to the maintenance of lower viscosities at shear rates investigated during grinding. Stirrer rotational speed interacts with solids concentration. For a given solids concentration, an optimal stirrer speed exists. The observed phenomena can be explained by the interaction of slurry rheology and the stress intensity of individual grinding bead. In addition, an empirical particle size-energy model provides a good fit (R2 > 0.904) to the grinding results under the experimental conditions investigated. Furthermore, the wear of grinding media beads is involved. ZrO2 beads have a lowest wear rate whereas the wear of SiO2 beads is most serious. The wear rate of Al2O3 beads is related to bead size.

[1]  C. Prestidge,et al.  Rheological investigations of sulphide mineral slurries , 1995 .

[2]  Eric Forssberg,et al.  Slurry rheology in wet ultrafine grinding of industrial minerals: a review , 2004 .

[3]  K. Husemann,et al.  The influence of suspension properties on ultra-fine grinding in stirred ball mills , 1999 .

[4]  Eric Forssberg,et al.  Parameter studies on the rheology of limestone slurries , 2006 .

[5]  Eric Forssberg,et al.  Parameter effects on wet ultrafine grinding of limestone through slurry rheology in a stirred media mill , 2006 .

[6]  P. Radziszewski,et al.  Determining the steel media abrasive wear as a function of applied force and friction , 2004 .

[7]  Jörg Schwedes,et al.  Theoretical and experimental investigation on particle and fluid motion in stirred media mills , 1999 .

[8]  A Jankovic,et al.  Variables affecting the fine grinding of minerals using stirred mills , 2003 .

[9]  Jaime E. Sepúlveda.  Methodologies for the evaluation of grinding media consumption rates at full plant scale , 2004 .

[10]  Jörg Schwedes,et al.  Comminution of ceramics in stirred media mills and wear of grinding beads 1 Extended version of the , 1999 .

[11]  C. C. Harris,et al.  The effect of additives on stirred media milling of limestone , 1997 .

[12]  R. Greenwood,et al.  A new method for determining the optimum dispersant concentration in aqueous grinding , 2002 .

[13]  Eric Forssberg,et al.  Prediction of product size distributions for a stirred ball mill , 1995 .

[14]  Roe-Hoan Yoon,et al.  Effect of media size in stirred ball mill grinding of coal , 1986 .

[15]  P. C. Kapur,et al.  Role of dispersants in kinetics and energetics of stirred ball mill grinding , 1996 .

[16]  C. C. Harris,et al.  A study on grinding and energy input in stirred media mills , 1996 .

[17]  Jörg Schwedes,et al.  Motion and stress intensity of grinding beads in a stirred media mill. Part 1: Energy density distribution and motion of single grinding beads , 1996 .

[18]  Jörg Schwedes,et al.  Motion and stress intensity of grinding beads in a stirred media mill. Part 2: Stress intensity and its effect on comminution , 1996 .

[19]  R. Klimpel.  The selection of wet grinding chemical additives based on slurry rheology control 1 To the memory of , 1999 .

[20]  Eric Forssberg,et al.  A study on the effect of parameters in stirred ball milling , 1993 .

[21]  Jörg Schwedes,et al.  Energy distribution and particle trajectories in a grinding chamber of a stirred ball mill , 1996 .