Effects of filling degree and viscosity of slurry on mill load orientation

Katubilwa, François M.; Moys, M.H.

doi:10.1016/j.mineng.2011.08.004

Cited by 17 publications

(6 citation statements)

References 7 publications

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“…As shown in Figure 6, the increase in the mill speed and in the subsequent raise in the centrifugation force caused the balls to release in higher angles from the lifters, thus increasing the shoulder angle. Variation of the shoulder angle with slurry filling is similar to the work conducted by Katubilwa and Moys [12] in a small pilot mill. Regarding the chart in Figure 6, the increase in the mill speed by 1% of the critical speed will lead to an increase in the shoulder angle by 1 degree.…”

Section: According Tosupporting

confidence: 79%

“…Moys et al [10,11] have studied the dynamic behavior of the load in wet condition in industrial as well as pilot scale. Katubilwa and Moys [12] have conducted some experiments for different viscosities and 60% of the critical speed by means of a pilot mill (552 mm diameter, 180 mm length, 18 lifters of 25 mm height and 20 • angle, 20% charge of ball with 10 mm diameter); they made a fluid by combination of water and glycerin oil with different densities 1000-1202 kg.m −3 (this density range is not applied in mineral industries) and then studied the effect of the slurry filling and viscosity inside the mill on the shoulder, toe, and pool angles. But in this article the real slurry (pulp) was used.…”

Section: Introductionmentioning

confidence: 99%

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Experimental observations of mill operation parameters on kinematic of the tumbling mill contents

Soleymani

Mahani

Rezaeizadeh

2016

Mechanics & Industry

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The present paper aims to investigate the key points of kinematic of contents inside the mill (load orientation), namely the shoulder, toe, impact, and pool angles. The kinematic of the mill contents in wet grinding is influenced by a range of parameters such as: media charge level (ball filling), slurry filling, and mill speed. In this work the influence of these operating parameters was investigated using a pilot mill (1000 × 500 mm). To this end, a Copper ore (-1000 μm) was used to prepare slurry at 50% solids concentration by mass. The tests covered a range of slurry filling (U) from 0 to 2.92 with ball filling 24% and 30% of mill volume and 6 different speeds between 60% and 85% of critical speed. It is observed as the mill speed increases, the more the impact angle will decrease. Toe angle increases in the range 15-25 degrees by formation of the pool in mill and exertion of the floating (buoyancy) forces to the particles inside the mill. The more the mill speed and the slurry filling increase, the more the shoulder angle will increase. The increase in slurry volume leads to the elevation of the pool level and therefore, the pool angle will exponentially decrease.

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Section: According Tosupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Experimental observations of mill operation parameters on kinematic of the tumbling mill contents

Soleymani

Mahani

Rezaeizadeh

2016

Mechanics & Industry

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“…The influence of material content on the behavior of fill and power of the mill drive during wet grinding was studied in [18] both visually and with the help of hardware. The volume of slurry with particles of crushed material varied from 0 to 300 % of the volume of cavities between the grinding bodies.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Establishing the effect of decreased power intensity of self-oscillatory grinding in a tumbling mill when the crushed material content in the intra-chamber fill is reduced

Deineka

Naumenko

2020

EEJET

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The influence of the content of crushed material in the intra-chamber grinding fill on the efficiency of the self-oscillatory grinding process in the tumbling mill was assessed. A dynamic effect of a significant decrease in self-oscillatory action of the two-fraction fill of the rotary chamber with an increase in the content of fine fraction was revealed by the method of visual analysis of motion patterns. A decrease in values of the following inertial fill parameters was established: maximum dilatancy υ max , the relative amplitude of self-oscillations ψ Rυ and a maximum share of the active part κ fam max with an increase in the degree of filling the gaps between particles of the coarse fraction κ mbgr. A decrease in the generalized complex degree of dynamic activation K a was also established. The effect is due to the strengthening of the cohesive properties of the incoherent coarse fraction under the influence of the fine fraction. There was a decrease in by 29 % for υ max, by 7 % for ψ Rυ , 2.9 times for κ fam max and 4.2 times for K a with an increase in κ mbgr from 0 to 1 at the degree of filling the chamber with the fill κ br = 0.45. Technological effect of a significant decrease in specific energy intensity and an increase in productivity of the innovative self-oscillatory grinding process in comparison with characteristics of the conventional steady-state process at a decrease in the content of crushed material in the fill was established. A process of milling cement clinker with grinding bo dies at relative size of 0.026 and κ br = 0.45 was considered. A decrease in specific energy intensity by 27 % at κ mbgr = 1, by 38 % at κ mbgr = 0.5625 and by 44 % at κ mbgr = 0 was found. An increase in relative productivity by 7 % at κ mbgr = 1, by 26 % at κ mbgr = 0.5625 and by 39 % at κ mbgr = 0.125 was established. The established effects will make it possible to forecast rational parameters of the self-oscillatory grinding process in a tumbling mill at the variation of the content of the crushed material in the fill Keywords: tumbling mill, content of crushed material in intra-chamber fill, self-oscillations, energy intensity of grinding

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“…Empirical parameters of θs and θt are given in Morrell, 11 and Katubilwa and Moys. 21 r m is the internal radius of the mill given by rm=D/2. Rezaeizadeh minus the area of lifters form cross section of mill and presented a new formula for r m in PhD thesis 22 where D is mill diameter, N is number of lifters, and A ′ is area of one lifter.…”

Section: Theoretical Considerationsmentioning

confidence: 99%

Experimental investigation of the power draw of tumbling mills in wet grinding

Soleymani

Fooladi

Rezaeizadeh

2016

Proceedings of the Institution of Mechanical Engineers, Part C:

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In comminution, mill power plays a major role from the economics standpoint and is a critical design criterion. It is influenced by a range of parameters such as media charge level (ball filling), slurry filling, slurry concentration and mill speed. In this work, the effects of these operating parameters were investigated using a pilot mill (1000 × 500 mm). To this end, a copper ore (−1000 µm) was used to prepare the slurry. The tests covered a range of slurry filling (U) from 0 to 1.7 with media charge between 12% and 36% of the mill volume and six different speeds between 60% and 85% of critical speed. A power analyser was utilized to measure mill power. Increase in mill speed and ball filling leads to a remarkable increase in the amount of the power. Preliminary results show that there is a definite trend between the power and the slurry filling U. Mill power draw is maximum at slurry concentration 60–70% and slurry filling 0.84. An empirical equation was given that fits the data reasonably well.

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Effects of filling degree and viscosity of slurry on mill load orientation

Cited by 17 publications

References 7 publications

Experimental observations of mill operation parameters on kinematic of the tumbling mill contents

Experimental observations of mill operation parameters on kinematic of the tumbling mill contents

Establishing the effect of decreased power intensity of self-oscillatory grinding in a tumbling mill when the crushed material content in the intra-chamber fill is reduced

Experimental investigation of the power draw of tumbling mills in wet grinding

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