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Isokangas E.,Metso Process Technology and Innovation | Valery W.,Innovation Farm | Jankovic A.,Innovation Farm | Sonmez B.,Metso Process Technology and Innovation
26th International Mineral Processing Congress, IMPC 2012: Innovative Processing for Sustainable Growth - Conference Proceedings | Year: 2012

The production of minerals for economic use is a two-stage process, involving mining to extract the mineral from the ground, and processing to convert the mineral into a marketable product. Generally, mining and processing have been viewed as self-contained entities. Both have separate objectives, separate cost centres and key performance indicators (KPIs) that do not reflect the customer/supplier relationships that inherently exist. However, mining and processing operations are inter-connected and therefore intimately inter-related with the performance of one operation affecting the performance of another. Optimizing each stage separately without considering the whole system often misses potential economic benefits and energy savings. During the past fifteen years, the authors have been involved in implementing a holistic methodology "Mine to Mill Process Integration and Optimisation (Mine to Mill PIO)" to maximize the overall profitability of the operation rather than just optimizing any individual process in a mining operation. Metso Process Technology and Innovation (PTI), along with their project partners, have conducted several projects to significantly increase their production- generating typically 5% to 20% higher throughput and improve the overall mine and concentrator performance through PIO methodology. This proven methodology has applications ranging from greenfield projects to long-standing operations with AG/SAG, HPGR or conventional grinding circuits. This paper explains the Mine to Mill PIO methodology and discusses the benefits of such an approach on the energy consumption, the overall costs and benefits of mining operations. The paper also summarizes several case studies illustrating the use of PTI methodology in a variety of applications.


Amelunxen P.,Aminpro Chile | Runge K.,Metso Process Technology and Innovation
Mineral Processing and Extractive Metallurgy: 100 Years of Innovation | Year: 2014

This paper reviews the key events in the history of flotation modeling from 1935 through 2013. The focus is on first order kinetics models with an emphasis on the commonly used methods in the design and engineering sector of extractive metallurgy. Some ideas for future direction are also provided.


Jankovic A.,Metso Process Technology and Innovation | Dundar H.,Hacettepe University | Mehta R.,Deloitte
Journal of the Southern African Institute of Mining and Metallurgy | Year: 2010

An extensive laboratory grinding study was carried out on a magnetite ore in order to assess the grinding behaviour of magnetic concentrate and tail from low intensity magnetic separation (LIMS). The test work involved Bond ball mill testing, rod milling, low intensity magnetic separation (LIMS), and batch ball milling down to product sizes of around P80~25 microns. A total of 18 Bond tests and over 150 batch grinding tests and sieve sizing were carried out. Throughout the grinding tests, power draw was continuously monitored. The relationship between the grinding energy and product size was analysed using the conventional energy-size concepts. It was found that the Rittinger equation fits the experimental data well. However, Bond's equation does not fit the experimental data well, and therefore a modified Bond equation was developed. Differences in grinding properties between the magnetic and non-magnetic component were analysed and compared to the bulk ore. It was found that grinding properties differ significantly and therefore separate grinding test work may be required for each grinding step in the magnetite ore beneficiation flowsheet. © The Southern African Institute of Mining and Metallurgy, 2010.


Tabosa E.,Metso Process Technology and Innovation | Runge K.,Metso Process Technology and Innovation | Holtham P.,Metso Process Technology and Innovation
International Journal of Mineral Processing | Year: 2016

It is clear that along with gas dispersion characteristics, the energy dissipated by the impeller is process determining in flotation, and its effect on flotation kinetics has been widely studied. However, turbulent conditions inside a flotation cell have usually only been changed by varying impeller speed or air flowrate or both. Therefore, there is a need to investigate not only these variables but also how changes in impeller/stator mechanism size and design, cell aspect ratio and cell design affect turbulence. This should lead to a better understanding of the effect of cell hydrodynamics on flotation performance. The aim of this work was to evaluate the role of flotation cell hydrodynamics on flotation performance in a fully instrumented 3m3 cell. The cell was operated at a copper concentrator in Australia with different combinations of airflow rates, impeller speeds and sizes and cell aspect ratio providing a wide range of hydrodynamic conditions. An analysis of the flotation cell performance showed that the overall copper recoveries were very similar for the conditions tested. However, by decoupling pulp effects from froth effects it was possible to determine whether the changes made affected the pulp zone and/or froth zone responses. The analysis showed that the overall recovery had the potential to be up to 10% higher if not limited by froth recovery. Comparing the metallurgical performance of the cell with the different hydrodynamic conditions it was found that the collection zone flotation rate was not directly related to overall energy dissipation, as is commonly observed at laboratory scale, where energy is usually only changed by varying impeller tip speed. Results suggest that it is the size of the turbulent zone, rather than just energy input, that affects flotation recovery. © 2016 Elsevier B.V.


Jankovic A.,Metso Process Technology and Innovation | Valery W.,Metso Process Technology and Innovation
Minerals Engineering | Year: 2013

Since the early days, there has been a general consensus within the industry and amongst grinding professionals that classification efficiency and circulating load both have a major effect on the efficiency of closed circuit ball mills. However, the effect of each is difficult to quantify in practice as these two parameters are usually interrelated. Based on experience acquired over the years and the investigative work conducted by F.C. Bond, it was established that the optimum circulating load for a closed ball mill-cyclone circuit is around 250%. This value is used as guideline for the design of new circuits as well as to assess the performance of existing circuits. The role of classification in milling appears to have been neglected in the current efforts to reduce the energy consumption of grinding. Two past approaches, experimental and modelling, for quantifying the effects of classification efficiency and circulating load on the capacity of closed ball mill circuits, are revisited and discussed in this paper. Application to the optimisation of existing circuits and design of new circuits is also discussed, with special attention to the development of more energy efficient circuits. © 2012 Elsevier Inc. All rights reserved.


Tabosa E.,Metso Process Technology and Innovation | Runge K.,Metso Process Technology and Innovation | Holtham P.,Metso Process Technology and Innovation | Duffy K.,Metso Process Technology and Innovation
Minerals Engineering | Year: 2016

Flotation is not a particularly energy intensive process. Therefore, flotation optimization has traditionally been focused on grade and recovery performance improvements. However, with the growing need for energy efficiency and the dramatic increase in flotation cell size in recent years it is worth considering how well energy is utilised within flotation cells. In conventional flotation cells a certain amount of energy is required to meet the basic requirements for flotation (air dispersion, solids suspension and particle-bubble collision). This paper investigates how that energy is dissipated in the flotation cell to determine the most efficient use of the imparted energy. The distribution of turbulence and its effect on flotation kinetics are investigated in a mechanical 3 m3 flotation cell for a range of hydrodynamic conditions. The effect of the different conditions are evaluated considering the Power Number (NP); a dimensionless number that is a useful hydrodynamic indicator as it represents the ratio of energy added to the flotation cell dissipated as shear to that used to generate bulk flow. Results show that flotation rate in the collection zone and the fraction of the cell with higher turbulence increases as more of the power drawn by the impeller is dissipated as shear in the impeller-stator region (higher Power Number). This should promote higher collision rates and more efficient use of the energy imparted in the flotation cell. © 2016


Jankovic A.,Metso Process Technology and Innovation | Suthers S.,CSIRO | Wills T.,Metso Process Technology and Innovation | Valery W.,Metso Process Technology and Innovation
Minerals Engineering | Year: 2015

Comparative dry grinding tests were conducted for two grinding flowsheet options using commercial aggregate as feed material: Option A, using a high pressure grinding roll (HPGR) in closed circuit with air classification, and Option B, using HPGR in closed circuit with a 2.36 mm screen, followed by a locked-cycle Bond test. Bond tests were also carried out on standard crushed feed passing 3.35 mm and 2.36 mm for comparison. The feed for the tests was screened and crushed to pass 10 mm. The air classifier produced a fine product with an 80% passing size (P80) of around 50 μm. In order to maintain comparability, the Bond tests were carried out using a 75 μm closing screen, producing a final product with a P80 of 57 μm. In all tests, the power consumption of the HPGR, Bond mill and air classifier were recorded directly using a power meter, while the Bond mill power consumption was also calculated using Bond's third law and other published methods. Testing determined that the specific energy consumption of the Option B circuit was 41.9% greater than Option A when evaluated using power logging, or 26.2% greater when calculated using Bond's law. Option A required 20.8-29.5% less energy per tonne of ore processed than Option B, a conservative estimate due to the finer grind size achieved. Further Bond tests showed that the work indices of standard crushed -3.35 mm and -2.36 mm feed were similar (15.0 and 15.3 kW h/t, respectively), while the HPGR crushed -2.36 mm feed produced a lower work index of 14.0 kW h/t. These results agree with observations by other workers that HPGR renders a sample more amenable to comminution, most likely due to the introduction of micro-cracks. Crown Copyright © 2014 Published by Elsevier Ltd. All rights reserved.


Meng J.,University of Queensland | Xie W.,University of Queensland | Brennan M.,University of Queensland | Tabosa E.,Metso Process Technology and Innovation | And 2 more authors.
IMPC 2014 - 27th International Mineral Processing Congress | Year: 2014

Turbulence and its distribution are of great importance in flotation cell design as they affect suspension of particles, air dispersion and particle-bubble collision rates, which in turn determine flotation performance. However, there is no mature technique to measure turbulence in three phase (liquid-solid-gas) systems such as in flotation cells. In this article, the authors present two new approaches that are suitable for measuring turbulence distribution in three phase systems and validate their applicability. The first technique uses a piezoelectric vibration sensor (PVS) to measure fluid kinetic energy standard deviation and the second technique applies electrical resistance tomography (ERT) to measure conductivity variation at a measurement position in a flotation cell. For the PVS technique, calibration of the sensor was performed to determine the values of parameters that were needed to calculate the force applied to the sensor. Then measurement was conducted in a 60L batch flotation cell and the results were compared with LDA measurement. This demonstrated that the piezoelectric sensor signal provides a good representation of fluid kinetic energy standard deviation at the position of measurement. For the ERT technique, conductivity distribution data was processed to give conductivity variations, which were then used to calculate fluid kinetic energy standard deviation at the measurement position. The spatial distribution of turbulence obtained by performing multiple measurements at different positions in the 60 litre batch flotation cell was found to agree with the PVS measurement results. These two techniques are potentially powerful tools for turbulence measurement in flotation environments, enabling a clearer understanding of turbulence's influence on flotation performance to be determined.


Jankovic A.,Metso Process Technology and Innovation | Valery W.,Metso Process Technology and Innovation | Sonmez B.,Metso Process Technology and Innovation | Oliveira R.,Metso Process Technology and Innovation
IMPC 2014 - 27th International Mineral Processing Congress | Year: 2014

The ball mill is the most common ore grinding technology today, and probably more than 50% of the total world energy consumption for ore grinding is consumed in ball mills. On the other hand, high pressure grinding roll (HPGR) technology is relatively new to the mining industry, with significant application only since the beginning of the 21st century. Both ball mills and HPGRs are typically used in closed circuit with classifiers. There is a general consensus within the industry that classification efficiency and circulating load both have a major effect on the efficiency of closed circuit ball mills. Metso Process Technology & Innovation (PTI) conducted a laboratory test program to understand the relationship between classification efficiency and circulating load, and the impact on the performance and capacity of ball mill circuits. However, the effects on HPGR performance are significantly different. Metso PTI has initiated a pilot scale test program to evaluate the size reduction performance of the HPGR under different circuit configurations. A series of pilot scale HPGR locked cycle tests were performed to simulate the following circuit configurations: including closed circuit with a screen, partial product recycle and edge recycle. This paper discusses the results from the pilot scale HPGR and laboratory scale ball mill test programs. The effect of circulating load and classification efficiency on the performance of ball mill circuits is compared to the effect on HPGR circuits. The fundamentals of grinding behavior are also discussed in order to explain the difference.

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