scholarly journals Experimental Study of Operational Parameters on Product Size Distribution of Tumbling Mill

2021 ◽  
pp. 095440892110627
Author(s):  
Moslem Mohammadi Soleymani
Keyword(s):  
Size Distribution ◽  
Critical Speed ◽  
Operational Parameters ◽  
Copper Ore ◽  
Mill Product ◽  
Slurry Concentration ◽  
Pilot Model ◽  
Grinding Media ◽  
Grinding Mechanism ◽  
Mill Speed

To assess the effects of the mill operating parameters such as mill speed, ball filling, slurry concentration and slurry filling on grinding process and size distribution of mill product, it was endeavored to build a pilot model with smaller size than the mill. For this aim, a pilot mill with 1 m × 0.5 m was implemented. There are 15 lifters with 50 mm height and face angle of 30˚. In the present work, the combination of the balls (40% of the balls with 60 mm diameter, 40% of the balls with 40 mm diameter and 20% of the balls with 25 mm diameter) was used as grinding media with 10%, 15%, 20% and 25% of the total volume of the mill. The experiments were carried out at 60%, 70%, 80% and 90% of the critical speed. The feed of the mill is copper ore with the size smaller than 25.4 mm, which d80 and d50 of them are 12.7 and 8 mm, respectively and slurries with 40%, 50%, 60%, 70% and 80% of solid and the slurry filling between 0.5 and 2.5. The results showed that the best grinding and grading occurs at 70–80% of the critical speed and ball filling of 20–25%. Optimized grinding was observed when the slurry volume is 1–1.5 times of the ball bed voidage volume and the slurry concentration is between 60% and 70%. The mill grinding mechanism in this work is a combination of both impact and abrasion mechanisms.

scholarly journals Experimental Study of Operational Parameters on Product Size Distribution of Tumbling Mill

2020 ◽  
Author(s):  
moslem mohammadi soleymani
Keyword(s):  
Size Distribution ◽  
Critical Speed ◽  
Operational Parameters ◽  
Copper Ore ◽  
Mill Product ◽  
Slurry Concentration ◽  
Pilot Model ◽  
Grinding Media ◽  
Grinding Mechanism ◽  
Mill Speed

Abstract To assess the effects of the mill operating parameters such as mill speed, ball filling, slurry concentration and slurry filling on grinding process and size distribution of mill product, it was endeavored to build a pilot model with smaller size than the mill. For this aim, a pilot mill with 1m × 0.5m was implemented. There are 15 lifters with 50mm height and face angle of 30˚. In the present work, the combination of the balls (40% of the balls with 60mm diameter, 40% of the balls with 40mm diameter and 20% of the balls with 25mm diameter) was used as grinding media with 10%, 15%, 20% and 25% of the total volume of the mill. The experiments were carried out at 60%, 70%, 80% and 90% of the critical speed. The feed of the mill is copper ore with the size smaller than 25.4 mm, which d80 and d50 of them are 12.7 and 8 mm, respectively and slurries with 40%, 50%, 60%, 70% and 80% of solid and the slurry filling between 0.5 and 2.5. The results showed that the best grinding and grading occurs at 70-80% of the critical speed and ball filling of 20-25%. Optimized grinding was observed when the slurry volume is 1-1.5 times of the ball bed voidage volume and the slurry concentration is between 60% and 70%. The mill grinding mechanism in this work is a combination of both impact and abrasion mechanisms.

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

2016 ◽  
Vol 230 (15) ◽  
pp. 2709-2719 ◽  
Author(s):  
Moslem M Soleymani ◽  
Majid Fooladi ◽  
Masood Rezaeizadeh
Keyword(s):  
Critical Speed ◽  
Empirical Equation ◽  
Design Criterion ◽  
Copper Ore ◽  
Slurry Concentration ◽  
Critical Design ◽  
Power Increase ◽  
Power Draw ◽  
Tumbling Mills ◽  
Mill Speed

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.

Experimental study the impact forces of tumbling mills

2016 ◽  
Vol 231 (2) ◽  
pp. 283-293 ◽  
Author(s):  
MM Soleymani ◽  
M Fooladi Mahani ◽  
M Rezaeizadeh
Keyword(s):  
Experimental Study ◽  
Critical Speed ◽  
Operating Parameters ◽  
Solid Concentration ◽  
Copper Ore ◽  
Slurry Concentration ◽  
Impact Forces ◽  
Tumbling Mills ◽  
Mill Speed ◽  
The Impact

Impact forces are one of the mechanisms for grinding in mill. This takes place when the particles elevated by the lifters get into cascade motion and their fall on the load causes the breakage of other particles. The present paper aimed to study the impact forces in terms of variables like: mill speed, solid charge filling (ball filling), slurry concentration, and slurry filling. In this work, the influence of these operating parameters was investigated using a pilot mill. To this end, a copper ore was used to prepare slurry at different solid concentration. The tests covered a range of slurry filling from 0 to 2 with five different balls filling between 12% and 36% of mill volume and six different speeds between 60% and 85% of critical speed. The results delineate that the increase in the mill speed leads to a remarkable increase in the amount and frequency of the impact forces. Increasing the charge volume leads to decrease the maximum impact forces. The results show that with the increase in slurry filling and the resulting formation of a pool, the impact forces will decrease. Moreover, it is found that with the increase in slurry concentration, the slurry will act as a damper decreasing the impact forces.

scholarly journals A process mineralogy approach to study the efficiency of milling of molybdenite circuit processing

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Ataallah Bahrami ◽  
Morteza Abdollahi ◽  
Mirsaleh Mirmohammadi ◽  
Fatemeh Kazemi ◽  
Abolfazl Danesh ◽  
...  
Keyword(s):  
Size Distribution ◽  
Open Circuit ◽  
Closed Circuit ◽  
Destructive Effect ◽  
Mill Product ◽  
Flotation Process ◽  
Comminution Process ◽  
Particles Size Distribution ◽  
Mineralogical Study ◽  
Mill Feed

AbstractThis study is conducted with the aim of investigating the efficiency of open and closed-circuit molybdenite ore comminution processes (primary and secondary mill, respectively), through mineralogical study of mills feed and product. For this purpose, particle size distribution, minerals distribution, degree of liberation and interlocking of minerals in mills feed and product were studied. According to the results, chalcopyrite, molybdenite, pyrite and covellite constitute the major part of the mineral composition of open-circuit mill feed. Minerals at the mill product, in the order of abundance include liberated molybdenite particles, liberated chalcopyrite and interlocked chalcopyrite with pyrite, liberated and interlocked pyrite particles, and associated silicate gangues. The d50 values of the feed and product particles of the open-circuit mill are equal to 13.80 and 13.40 microns, respectively. Degree of liberation of molybdenite for the feed and product of this mill is almost the same and is equal to 98.0%. Closed-circuit mill feed includes, in order of is abundance, liberated molybdenite particles in the form of blades and irregular polygonal shapes, liberated and interlocked chalcopyrite, and liberated and interlocked pyrite particles with gangue minerals. Molybdenite particles in the mill product are almost completely liberated, and the degree of liberation values of chalcopyrite and pyrite are 84.40% and 91.40%, respectively. According to particles size distribution of the feed (d50 equal to 25.03 microns) and the product (d50 equal to 24.24 microns) of closed-circuit mill, it can be stated that comminution is not well-operated in closed-circuit mill due to the low solid percentage of closed-circuit mill feed and the inefficiency of hydrocyclone. Examination of Mo, Cu, and Fe grade variations for 10 days in both off and on modes of mill shows that closed-circuit mill does not have an impact on comminution process. It can even be concluded that the mill has a destructive effect the flotation process by producing slimes.

Application of Three-Parameter Distribution to Approximate the Particle Size Distribution Function of Comminution Products of Dolomitic Type of Copper Ore

2017 ◽  
Vol 62 (2) ◽  
pp. 411-422 ◽  
Author(s):  
Alona Nad ◽  
Marian Brożek
Keyword(s):  
Particle Size ◽  
Distribution Function ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Size Distribution Function ◽  
Copper Ore ◽  
Particle Size Fractions ◽  
Particle Size Distribution Function ◽  
Particle Strength ◽  
Parameter Function

AbstractThe paper presents the results of analyze the particle size distribution function of comminution products of dolomitic type of copper ore. The breakage tests for single irregular particles were performed with using a hydraulic press device. The authors prepared five particle size fractions of each material, within ranges: 16-18 mm, 18-20 mm, 20-25 mm, 25-31,5 mm and 31-45 mm. The particle size distribution function of single-particle breakage test was calculated separately for each size fraction. In addition, the cumulative particle size distribution function for five particle size fractions was presented. In theoretical part the study of applied functions of particle size distribution for comminution a set of particles and models of crushing single particles was performed. In that paper the curves of the particle size distribution were approximated by the three-parameter function, which parameters depend on the particle strength and material type. For conformity assessment the model distribution function to the empirical distribution function a residual deviation and non-linear correlation coefficient were calculated. The three-parameter function approximating agrees well with the particle size distribution obtained from experimental data. The dependence of the parameters of a particle size distribution function on the dolomite particle strength was presented. The results indicate the identity of single particle grinding mechanism by slow compression of irregular particles of dolomitic type of copper ore, regardless of the initial particle size.

scholarly journals Grinding Kinetics Adjustment of Copper Ore Grinding in an Innovative Electromagnetic Mill

2018 ◽  
Vol 8 (8) ◽  
pp. 1322 ◽  
Author(s):  
Marta Wołosiewicz-Głąb ◽  
Paulina Pięta ◽  
Dariusz Foszcz ◽  
Szymon Ogonowski ◽  
Tomasz Niedoba
Keyword(s):  
Particle Size ◽  
Size Fraction ◽  
Processing Parameters ◽  
Relative Increase ◽  
Grinding Process ◽  
Particle Size Fraction ◽  
Copper Ore ◽  
Media Type ◽  
Grinding Media ◽  
Ultrafine Grinding

The paper presents a study on the effectiveness of the grinding process in an electromagnetic mill devoted to ultrafine grinding, and the influence of processing parameters on the mill’s performance. The research was focused on the optimization of the duration of the grinding process and selection of the grinding media type in order to obtain the highest relative increase of the selected particle size fraction. Copper ore with a particle size between 0–1 mm was used in the experiments. A model was created that determines the relationship between the processing time and efficiency of the grinding, and can be used for the optimization of the process. A comparison of the relative growth of particle size fractions in milling products was performed. The obtained milling efficiency results measured by the growth of the analyzed particle size fraction in the milling product confirmed that the best grinding media set includes a grinding medium with a diameter of 1 mm and a length of 10 mm.

scholarly journals Influence of the Feed Moisture, Rotor Speed, and Blades Gap on the Performances of a Biomass Pulverization Technology

2014 ◽  
Vol 2014 ◽  
pp. 1-5
Author(s):  
Siyi Luo ◽  
Yangmin Zhou ◽  
Chuijie Yi ◽  
Yin Luo ◽  
Jie Fu
Keyword(s):  
Particle Size ◽  
Energy Consumption ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Specific Energy ◽  
Rotor Speed ◽  
Operational Parameters ◽  
Product Particle ◽  
Dry Conditions ◽  
Feed Moisture

Recently, a novel biomass pulverization technology was proposed by our group. In this paper, further detailed studies of this technology were carried out. The effects of feed moisture and crusher operational parameters (rotor speed and blades gap) on product particle size distribution and energy consumption were investigated. The results showed that higher rotor speed and smaller blades gap could improve the hit probability between blades and materials and enhance the impacting and grinding effects to generate finer products, however, resulting in the increase of energy consumption. Under dry conditions finer particles were much more easily achieved, and there was a tendency for the specific energy to increase with increasing feed moisture. Therefore, it is necessary for the raw biomass material to be dried before pulverization.

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