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Jayasundara C.T.,University of New South Wales | Yang R.Y.,University of New South Wales | Yu A.B.,University of New South Wales | Rubenstein J.,Xstrata Technology
International Journal of Mineral Processing | Year: 2010

IsaMill™ is a high-speed stirred mill used in the mineral industry for a range of milling duties from ultra-fine to coarse grinding. In this work, numerical simulations based on the discrete element method (DEM) were performed to investigate the particle flow in a dry stirred mill with a similar configuration to that of an IsaMill™. The effects of operational variables such as mill loading and rotation speed on flow properties such as flow velocity, power draw, collision frequency, collision energy and total impact energy were analysed. The results showed that increasing mill loading or mill speed increases impact energy between particles. Moreover, physical experiments were conducted to quantify grinding performance under similar conditions. The experimental results showed that the grinding in the mill follows the first order kinetics, and the rate constant can be correlated to impact energy. The findings are useful to understand and optimise the particle flow and grinding behaviour of IsaMills™. The proposed methodology may also apply to other stirred mills. © 2010 Elsevier B.V. All rights reserved.

Jayasundara C.T.,University of New South Wales | Yang R.Y.,University of New South Wales | Yu A.B.,University of New South Wales | Curry D.,Xstrata Technology
Minerals Engineering | Year: 2011

Mill wear is a critical issue in mineral industries. It affects mill performance and the cost of replacing worn parts is high. Understanding wear and its effect would provide a useful insight for process optimisation. This paper combines the discrete element method (DEM) with a commonly used wear model to predict the wear pattern of stirring discs in a model IsaMill. The results show that wear is more severe at the outer face of discs and the lifting side of holes. The simulated wear pattern has been compared with those observed in practice. The effect of disc wear on the flow of grinding media is also examined, showing that with the increasing wear, impact energy increases while power draw shows a mix of slight increase and decrease. The findings would be useful to the improvement in the design and control of IsaMills. © 2011 Elsevier Ltd. All rights reserved.

Grano S.,University of Adelaide | Zanin M.,University of South Australia | Pease J.,Xstrata Technology
Mineral Processing and Extractive Metallurgy: 100 Years of Innovation | Year: 2014

This paper discusses the drivers and imperatives for innovative changes in flotation plant practice over the last 30 years. Improvements in characterisation technology have led to improved understanding of contributions to inefficient mineral separation in flotation plant cells and circuits. In some cases this has also led to new process technology and approaches to targeted plant designs which may be applied globally. Technology improvements may drive further developments in characterisation tools and flotation technology.

Rule C.,Anglo American Platinum Ltd. | De Waal H.,Xstrata Technology
METPLANT 2011 - Metallurgical Plant Design and Operating Strategies | Year: 2011

In 2003, Anglo Platinum, in a joint development with Xstrata Technology, installed the world's first 10 000 litre IsaMill™ in a concentrate regrind duty at the Western Limb Tailings Re-treatment Plant. The success of that installation was the enabling event for Anglo Platinum to proceed with a substantial investment in horizontal stirred milling technology. Since 2006 an additional three IsaMills™ in concentrate regrind duties and a further 18 IsaMills™ in the more technically challenging coarse grinding mainstream applications, have been commissioned in group Concentrator operations - bringing the total number of IsaMills™ installed in Anglo Platinum plants to 22. A collaborative approach between Anglo Platinum and Xstrata Technology towards improving milling efficiency and reducing operating costs, through internal mill component wear optimization and operating recipe development, has resulted in further improvements in the overall success of IsaMills™ in the flow sheets of many Anglo Platinum operations. The addition of IsaMills™ in the Anglo Platinum flow sheets has improved plant PGM recoveries by as much as 5%. This paper explores the improvements made to the IsaMills™ flow sheet and mill internal design and shares some of the operating experience with IsaMills™ technology in Anglo Platinum.

Van Der Westhuizen A.P.,University of Cape Town | Govender I.,University of Cape Town | Mainza A.N.,University of Cape Town | Rubenstein J.,Xstrata Technology
Minerals Engineering | Year: 2011

Stirred milling is continually gaining acceptance in the mineral processing industry. The IsaMill™ is a high intensity stirred mill with a horizontal configuration and internal classification. The present work describes the use of Positron Emission Particle Tracking (PEPT) to trace the motion of a media bead in a simplified IsaMill™ rig. The rig has the same inner dimensions and disc sizes as the real M20 IsaMill™ but is a closed unit without any flow through, no product separator and only three discs. The PEPT system has the advantage of being able to obtain detailed charge motion measurements in opaque and aggressive environments such as those encountered in grinding processes. Glass beads (3 mm) and ceramic media (3.5 mm) were tracked over a range of volumetric fillings and rotational speeds. An analysis of the resultant trajectory fields in terms of media location (occupancy), velocity, and acceleration is presented. © 2010 Elsevier Ltd. All rights reserved.

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