Better resource efficiency by improved comminution
2012 (English)Conference paper, Presentation (Other academic)
The comminution stage is usually not only the most energy intensive step within mineral processing plants, but it is also crucial for all subsequent steps in mineral beneficiation. Sufficiently liberating the valuable mineral grains from particles by grinding an ore to finer particle sizes is the key prerequisite for efficient mineral separation in downstream processes. When considering the general trends in processing mineral ores, i.e. towards ores of lower grade, fine grained ores and more complex mineralogy, improved comminution becomes even more relevant in terms of both energy efficiency and utilization of mineral raw materials. For size reduction and liberation various comminution devices of different design and operating principles are available. Their selection and operation is often not optimal due to limited ore characterization. Lack of knowledge with respect to ore texture and mineral associations, this also seen against the backdrop of the variability within an ore body, frequently results in aiming at too fine product particle sizes. Adjusting the breakage mechanism to the texture of a particular ore, based on e.g. advanced electron microscopy or computer tomography analyses, can lead to enhanced liberation already at coarser particle sizes, thus allowing decreasing the size reduction ratio. Selection of the appropriate breakage mechanism or equipment type respectively, does also affect the energy utilization in the downstream processing as certain types of devices particularly support the formation of micro cracks. Inducing micro cracks, partly occurring at the mineral grain boundaries, results in particle weakening and increased liberation and therefore facilitates subsequent grinding and concentrating processes. Design and operating conditions of comminution devices can then be further optimized using advanced modeling and simulation methods. Particle simulations based on computational physics, as the discrete element method or other, allow improving the performance of mills and crushers with respect to energy utilization and wear. Finally improved comminution can also be achieved by process optimization on grinding circuit level as well as process plant level. This comprises the introduction of improved classification methods within comminution circuits but also the pre-concentration by removing liberated gangue already at coarser particle sizes, or by successive separation and size reduction, for instance within staged grinding and flotation.
Place, publisher, year, edition, pages
Research subject Mineral Processing
IdentifiersURN: urn:nbn:se:ltu:diva-40474Local ID: f9ff7eb6-ac5a-4bc7-8325-1cbb18dae501OAI: oai:DiVA.org:ltu-40474DiVA: diva2:1013996
International Conference on Sustainable Mineral Processing : 11/12/2012 - 13/12/2012
Godkänd; 2012; 20121220 (janros)2016-10-032016-10-03Bibliographically approved