Correlation of grinding rate of gibbsite with impact energy in tumbling mill with mono-size balls

Kano, Junya; Mio, Hiroshi; Sanda, Fumio; Miyazaki, Miyuki

doi:10.1016/s0892-6875(01)00138-8

Cited by 32 publications

(10 citation statements)

References 14 publications

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“…particles (d 90 ¼ o 10 mm), vibratory ball milling, planetary ball milling (Kano et al, 2001) and air jet milling (Midoux et al, 1999) are commonly used methods. In these mills particle size is reduced by impact, shear, attrition or compression or a combination of them (Balaz et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Effect of mill type on the size reduction and phase transformation of gamma alumina

Chauruka

Hassanpour

Brydson

et al. 2015

Chemical Engineering Science

119

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We study the effect of stress modes from three mills on structure of gamma-alumina. Extent of size reduction and mechanochemical effects are analysed. Jet milling is effective in size reduction and does not initiate mechanochemistry. Shear-induced phase transformation is observed in planetary ball mill. Transformation is by slip on alternate close packed oxygen layers from ccp to hcp. a b s t r a c tThe influence of stress modes and comminution conditions on the effectiveness of particle size reduction of a common catalyst support; γ-Alumina is examined through a comparative assessment of three different mill types. Air jet milling is found to be the most effective in reducing particle size from a d 90 of 37 mm to 2.9 mm compared to planetary ball milling (30.2 mm) and single ball milling (10.5 mm). XRD and TEM studies confirm that the planetary ball mill causes phase transformation to the less desired α-Alumina resulting in a notable decrease in surface area from 136.6 m 2 /g to 82.5 m 2 /g as measured by the BET method. This is consistent with the large shear stresses under high shear rates prevailing in the planetary ball mill when compared to the other mill types. These observations are consistent with a shear-induced phase transformation mechanism brought about by slip on alternate close packed oxygen layers from a cubic close packed to a hexagonal close packed structure.

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Section: Introductionmentioning

confidence: 99%

Effect of mill type on the size reduction and phase transformation of gamma alumina

Chauruka

Hassanpour

Brydson

et al. 2015

Chemical Engineering Science

119

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“…２・４ Impact energy The impact energy of balls was calculated to evaluate the liner design. It has been already reported that this impact energy correlates with the grinding rate constant in ball milling under various grinding conditions [12][13][14][15][16] , and the relationship between the specif ic impact energy and the grinding rate constant is linear. Therefore, the grinding rate can be predicted and milling performance is estimated by calculating the impact energy.…”

Section: ・３ Simulation Conditionmentioning

confidence: 91%

“…This relationship was given by a straight line, regardless of grinding conditions; e.g. mill scale 13) , ball-filling 14) , ball size 15) or ground materials 16) . The specific impact energy is also useful for the designing of the planetary ball mill.…”

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confidence: 99%

Estimation of Liner Design in a Tube Mill by Discrete Element Method

Mio

Kano

Sanda

et al. 2007

Journal of the Mining and Materials Processing Institute of Jap

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１．IntroductionMany industries have large-scale ball mills in grinding processes because the ball milling is one of the easiest methods for producing powder, and size reduction is, of course, one of the most important unit operations. For example, in a cement production process, the grinding is taken in initial and final stages. The raw materials of limestone, hematite and silica solids are ground in a tube mill at the initial stage, and cement clinker, which is produced by calcinations in a rotary kiln, is also ground with gypsum to produce the final product. It has been reported that about 100 kWh of electricity must be needed to produce 1.0 ton of cement, and more than 60% of total electricity is consumed in the grinding process 1) . The wear of balls is another serious problem; e.g. it was reported that the consumption of balls is 850 g/day 2) . Therefore, it is important to g rind materials with high g rinding eff iciency, and optimisation of ball milling is necessary.Most of tube mills have liner on the inner mill wall as lifter in order to increase the grinding efficiency, and ball charge motion is sensitive to the shape of liner 3) . There are several investigations into the tube milling [4][5][6] , and analysis of tumbling ball milling by using a computational simulation based on the Discrete Element Method (DEM) 7-10) had been developed. The ball charge motion with considering presence of powder was simulated by Authors 11) . The effect of presence of powder in a ball mill was considered by frictional coefficient, which was obtained by an angle of repose of powder sample. The authors had proposed the impact energy which was calculated from the relative velocity on the collision, and the correlation between the grinding rate in the experimental work and the specific impact energy of balls was found out 12) . This relationship was given by a straight line, regardless of grinding conditions; e.g. mill scale 13) , ball-filling 14) , ball size 15) or ground materials 16) . The specific impact energy is also useful for the designing of the planetary ball mill. The pot rotational direction and speed ratio between pot and disk rotations were optimised by the impact energy, 17) and the scale-up method of the planetary ball mill was proposed 18) . Therefore, this impact energy has a high potential to estimate the grinding performance in an industryscale tube mill. The tube mill in cement industry has liner on the inner mill wall, and there are several liner designs. People want to know the effect of the liner shape on the grinding performance, however each mill has some compartment with different liner shape, and the type of classifier is also different. Thus, it is quite difficult to evaluate the effect of the liner design on the grinding performance.In this paper, the modelling of the liner in the tube mill was conducted by DEM. Ball charge motions in five tube mills having different shapes of liner design; i.e. MODEL I (duolift), II (steps), III (step wave) and IV (lifter liner), and O (without liner) are simu...

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“…However it is a variable of interest because it relates to the efficiency of the process. In the case of grinding it is desired to maximise the p-p impact energy, which is correlated to grinding rate [4], while minimising the power draw to lower the cost and produce high quality product. To overcome the obstruction of obtaining p-p impact energy we have used a discrete element method (DEM) model of a horizontal rotating drum to obtain this data.…”

Section: Introductionmentioning

confidence: 99%