EFFECT OF COMMINUTION ON PARTICLE SHAPE AND SURFACE ROUGHNESS AND THEIR RELATION TO FLOTATION PROCESS: A REVIEW | ||
| JES. Journal of Engineering Sciences | ||
| Article 14, Volume 37, No 3, May and June 2009, Pages 711-741 PDF (925.69 K) | ||
| Document Type: Research Paper | ||
| DOI: 10.21608/jesaun.2009.126503 | ||
| Author | ||
| Mahmoud M. Ahmed | ||
| Mining and Metallurgical Engineering Department, Faculty of Engineering, Assiut University, Assiut 71516, Egypt | ||
| Abstract | ||
| The geometry of particles has an influence on the physical and chemical actions occurring on the particle surface within the technological processes. This illustrates the important of the exact geometrical evaluation of the particles by means of quantified particle parameters. These parameters can be used to differentiate between different materials or to correlate them with the different processes. The essential characteristics of the distinction of particles are size, shape and surface roughness. Generally, particle shape and surface roughness can be considered as important parameters in the prediction of the behavior of particles individually or collectively. These parameters are of great importance to industries employing various materials in a powder form. These industries include many of the raw materials in civil and chemical engineering, pharmaceutical, mining industries, pigments, metals, ceramics, pills, foods, and industries interested with population of atmospheric dusts, smoke and grit. These parameters have not been currently reviewed satisfactory in the mineral processing field. Therefore, this review research is concerned with the different methods used to identify the particle shape and surface roughness and also to relate these parameters with the behavior of some mineral processing operations, especially comminution and flotation processes. The surface roughness of mineral particles has influenced the fundamental processes of particle-bubble attachment and the other subprocesses in froth flotation. The contact angle is dependent on the surface roughness. The modification of the wettability due to surface roughness can be greatly enhanced in the fractal surface; that is the fractal surface will be supperrepellent/superwettable to a liquid when the contact angle is greater/less than 900 . Correlations were found between the shape properties, surface roughness values and wettability. The dry grinding has produced relatively rough particle surfaces with a high concentration of microstructural defects while the wet grinding produced smoother cleaner surfaces. The dry ground samples exhibited more stable, higher loaded froths and faster flotation kinetics. | ||
| Keywords | ||
| Particle shape; Surface roughness; Fractal; Comminution; Flotation; Wettability | ||
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