Microscale insights into the influence of grinding media on spodumene micro-flotation using mixed anionic/cationic collectors

Modeling of wet stirred media mill processes is challenging since it requires the simultaneous modeling of the complex multiphysics in the interactions between grinding media, the moving internal agitator elements, and the grinding fluid. In the present study, a multiphysics model of an HIG5 pilot vertical stirred media mill with a nominal power of 7.5 kW is developed. The model is based on a particle-based coupled solver approach, where the grinding fluid is modeled with the particle finite element method (PFEM), the grinding media are modeled with the discrete element method (DEM), and the mill structure is modeled with the finite element method (FEM). The interactions between the different constituents are treated by loose (or weak) two-way couplings between the PFEM, DEM, and FEM models. Both water and a mineral slurry are used as grinding fluids, and they are modeled as Newtonian and non-Newtonian fluids, respectively. In the present work, a novel approach for transferring forces between grinding fluid and grinding media based on the Reynolds number is implemented. This force transfer is realized by specifying the drag coefficient as a function of the Reynolds number. The stirred media mill model is used to predict the mill power consumption, dynamics of both grinding fluid and grinding media, interparticle contacts of the grinding media, and the wear development on the mill structure. The numerical results obtained within the present study show good agreement with experimental measurements.

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Effect of grinding media properties and stirrer tip speed on the grinding efficiency of a stirred mill

Powder Technology ◽

10.1016/j.powtec.2021.01.022 ◽

2021 ◽

Vol 382 ◽

pp. 556-565

Author(s):

Wang Guo ◽

Peng Gao ◽

Zhidong Tang ◽

Yuexin Han ◽

Xiangzhi Meng

Keyword(s):

Grinding Media ◽

Grinding Efficiency

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A Comparative Study of Energy Efficiency in Tumbling Mills with the Use of Relo Grinding Media

Metals ◽

10.3390/met11050735 ◽

2021 ◽

Vol 11 (5) ◽

pp. 735

Author(s):

Nikolay Kolev ◽

Petar Bodurov ◽

Vassil Genchev ◽

Ben Simpson ◽

Manuel G. Melero ◽

...

Keyword(s):

Energy Efficiency ◽

Test Procedure ◽

Mining Industry ◽

Slight Modification ◽

Index Test ◽

Grinding Media ◽

Work Index ◽

Mineral Sample ◽

Tumbling Mills ◽

Bond Tests

An evaluation of Relo grinding media (RGM, Reuleaux tetrahedron-shaped bodies) performance versus standard grinding media (balls) was made through a series of grinding tests, including a slight modification of the standard Bond test procedure. Standard Bond tests showed a reduction in the Bond ball mill work index (wi) of the mineral sample used in this study when using Relo grinding media. The modified Bond test procedure is based on using the standard Bond ball work index test but changing the circulating loads (350%, 250%, 150%, 100%). The comparative tests with RGM were carried out at the same number of revolutions as the grinding tests with balls at respective circulating load. The RGM charge yielded a 14% higher net undersize product than balls, which hints at improving energy efficiency and the potential for significant mining industry benefits.

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Analysis of the breakage rate function for selected process parameters in quartzite milling

Chemical and Process Engineering ◽

10.2478/v10176-012-0011-4 ◽

2012 ◽

Vol 33 (1) ◽

pp. 117-129 ◽

Cited By ~ 7

Author(s):

Tomasz Olejnik

Keyword(s):

Process Parameters ◽

Rate Function ◽

Variable Number ◽

Specific Rate ◽

Gardner Equation ◽

Contact Points ◽

Batch System ◽

Grinding Media ◽

Breakage Rate ◽

The Impact

Analysis of the breakage rate function for selected process parameters in quartzite milling The paper presents the results of studies on quartzite milling in a ball mill. The milling was conducted in a batch system, for diversified compositions of balls. The milling product was subjected to granulometrical, morphological and strength analyses. On the basis of the developed Reid's theory and using the Austin-Gardner equation, a form of the function circumscribing the specific rate of comminution of selected size fractions was determined. The values of the breakage rate function bi, j for the mill's apparatus conditions were determined. The impact was investigated for a variable number of grinding media contact points on the values of specific rate S and the values of the breakage rate function bi, j. Furthermore, the values of coefficients occurring in the equations circumscribing the specific rate of milling S and breakage parameter bi, j were determined.

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On sinterability of nanostructured W produced by high-energy ball milling

Journal of Materials Research ◽

10.1557/jmr.2007.0166 ◽

2007 ◽

Vol 22 (5) ◽

pp. 1200-1206 ◽

Cited By ~ 61

Author(s):

R. Malewar ◽

K.S. Kumar ◽

B.S. Murty ◽

B. Sarma ◽

S.K. Pabi

Keyword(s):

Sintered Density ◽

Sintering Temperature ◽

High Energy ◽

Deformation Bands ◽

Dramatic Decrease ◽

Powder Charge ◽

Grinding Media ◽

Energy Ball ◽

High Level ◽

First Time

The present investigation reports for the first time a dramatic decrease in the sintering temperature of elemental W from the conventional temperature of ≥2500 °C to the modest temperature range of 1700–1790 °C by making the W powder nanostructured through high-energy mechanical milling (MM) prior to sintering. The crystallite size of the initial W powder charge with a particle size of 3–4 μm could be brought down to 8 nm by MM for 5 h in WC grinding media. Further milling resulted in a high level of WC contamination, which apparently was due to work hardening and the grain refinement of W. A sintered density as high as 97.4% was achieved by sintering cold, isostatically pressed nanocrystalline (8 nm) W powder at 1790 °C for 900 min. The microstructure of the sintered rods showed the presence of deformation bands, but no cracks, within a large number of W grains. The mechanical properties, when compared with the hardness and elastic modulus, of the sintered nano-W specimen were somewhat superior to those reported for the conventional sintered W.

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Development of a method to measure charges in tumbling mills

Rem Revista Escola de Minas ◽

10.1590/s0370-44672014000300011 ◽

2014 ◽

Vol 67 (3) ◽

pp. 311-316

Author(s):

Eduardo Nozawa Caetano de Araujo ◽

Homero Delboni Jr.

Keyword(s):

Low Cost ◽

Total Charge ◽

Main Aspect ◽

Product Size ◽

Confined Spaces ◽

Power Draw ◽

Grinding Media ◽

Tumbling Mills ◽

The Common ◽

Tumbling Mill

Tumbling mills are often taken as the object of optimization studies because they are a type of equipment that consume large amounts of energy. Among the current available resources to conduct such studies, mathematic modelling presents great efficiency due to its low cost, speed and reliability. The total charge and grinding media charge are very important variables to conduct modelling exercises that aim at power draw and product size distribution forecasting. However, the common measurement methods require people entering the equipment, which carries a number of adversities related to confined spaces. In this regard, this paper presents the development of a method and the prototype of a device able to measure tumbling mill charges, quickly, precisely, with low cost and, above all, ensuring safety. The result of this work is a method that allows equivalent or superior precision in comparison to the existing methods, whose main aspect is to eliminate the requirement of people entering dangerous environments, such as tumbling mills.

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