• Korean Journal of Materials Research
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• v.25 no.6
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• pp.305-316
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• 2015

The study of grinding behavior characteristics on the metal powders has recently gained scientific interest due to their useful applications to enhance advanced nano materials and components. This could significantly improve the property of new mechatronics integrated materials and components. So, a new evaluation method for standardizing grinding equipment and a comparative study for the grinding experiment during the grinding process with various grinding mills were investigated. The series of grinding experiments were carried out by a traditional ball mill, stirred ball mill, and planetary ball mill with various experimental conditions. The relationship between the standardization of equipment and experimental results showed very significant conclusions. Furthermore, the comparative study on the grinding experiment, which investigated changes in particle size, particle morphology, and crystal structure of materials with changes in experimental conditions for grinding equipment, found that the value of particle size distribution is related to the various experimental conditions as a revolution speed of grinding mill and media size.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.500-507
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• 2008

By Using various grinding mill in powder cosmetics manufacturing process; screen milt and pin mill, jet mill, properties of the powder and grinding mills were studied; talc, mica, nylon powder, silica, titanium dioxide. Besides, the experiments fur evaluation of grinding were performed by using iron oxides those are tracers. In powders of plate shape, they were grinded more vertically than horizontally at the screen mill and pin mill, although were all grinded vertically and horizontally at the jet mill. The spheric powders became the primary particles or aggregation by electrostatic interaction at the screen mill and pin mill. But, at the jet mill, they resulted the agglomeration or transformation or damage up to 2bar. Titanium dioxides became the primary particles by all grinding mill. Pin mill has an excellent result in experiments which is a change of the tone of color by grinding. From these results, suggest that the jet mill is used to pre-treat of powders of plate shape in practical cosmetic manufacturing process, and the screen mill and pin mill are used to match the color of powder cosmetics. If industrial process condition is taken into consideration, suggest that 4times of grinding is excellent on grinding effect by the screen mill, and twice grinding by the pin mill and grind air pressure of 1bar by the jet mill.

• Journal of Biosystems Engineering
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• v.25 no.1
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• pp.39-46
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• 2000

This work was conducted to study the operating characteristics of a grinding system designed to obtain fine rice husk ash powder. To find better utilizing of rice husk, a valuable by-product from rice production, once the rice husk was incinerated and the thermal energy was recovered from the furnace, the ash was fed and pulverized in the grinding system resulting a fine powder to be used as a supplementary adding material to the portland cement manufacturing . The rice husk ash grinding system consisted of a high speed centrifugal fan for the preliminary coarse milling and a dry-type stirred ball mill for the subsequent fine grinding . Total grinding time 9 5, 15, 30, 45 min), impeller speed (250, 500, 750 rpm) , and mixed ratio (4.8, 7.9, 14.9) were three operating factors examined for the performance of a stirred ball mill used for the fine grinding of ash. With the stirred ball mill used in this study, the minimum attianable mean diameter of rice husk ash powder appeared to be 2 ${\mu}{\textrm}{m}$. During the find grinding, the difference in specific surface area of powder showed an increase and the grinding energy efficiency decreased with the increase in total grinding time, impeller speed ,and mixed ratio. For the operating conditions employed , the resulting mean diameter of fine ash powder, specific energy input, and grinding energy efficiency were in the range of 1.79 --16.04${\mu}{\textrm}{m}$, 0.072-5.226kWh/kg, an d1.11-12.15$m^2$/Wh, respectively. Grinding time of 30 min , impeller speed of 750 rpm, and mixed ratio of 4.8 were chosen as the best operating conditions of the stirred ball mill for fine grinding . At these conditions, mean particle diameter of the fine ash, grinding energy efficiency, grinding throughtput, and specific energy input were 2.73${\mu}{\textrm}{m}$, 3.95$m^2$/Wh, 0.25kg/h, and 1.22kWh/kg, respectively.

• Korean Journal of Materials Research
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• v.17 no.10
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• pp.532-537
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• 2007

A series of wet grinding experiments have been carried out using a stirred ball mill to systematically investigate consideration of grinding characteristics. The particle size distribution and median diameter of the grinding consumption power for a given grinding time were considered. Also, the effect of grinding aids on particle size and grinding consumption energy defined as the summation of grinding power was investigated. The grinding aids had influence on the smaller products size and decrease grinding consumption energy because the function of grinding aids were to be attribute to the prevention of agglomeration and ball and grinding chamber wall coating of sample powder. The grinding process seemed to be controlled by the force of agglomeration of the ground products. It was demonstrated that the particle size and grinding consumption energy could be more decreased by the addition of grinding aids.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.11a
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• pp.27.2-27.2
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• 2009

Grinding characteristics for aluminium and carbon nanotubes (CNTs) powder during traditional and planetary ball milling investigated from the viewpoint of particle behaviour with the aimat developing CNT-dispersed samples ground based on powder metallurgy routes.In this work, a comparison between the pure aluminium and CNT input aluminium grinding was carried out to determine grinding time effect on size reduction.We observed that the use of the curly small-diameter multi-walled carbon nanotubes (MWCNTs) attributed to the beneficial role of the MWCNTs as grinding aids. It is suggested that careful choices of the sizes of CNTs and Al powders would allow fine-grinding of composite particles with uniformly distributed CNT reinforcements thereby ensuring improved properties of the final composites produced by low-temperature compacting.

• Cement Symposium
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• no.1
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• pp.50-55
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• 1973

Improvement of grinding efficiency about open circuit grinding mill in cement production was investigated and the results were as follows; 1. Controlled the steel ball by charging ratio. 2. Raised the slot ratio from 3$\%$ to 4.5$\%$

• Korean Journal of Materials Research
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• v.17 no.11
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• pp.606-611
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• 2007

This study was conducted to beneficiation of magnesite by dry grinding and air classification. The raw ore was ground in a ball mill and pin mill controlled with grinding time and linear velocity of grinding media and fractionated in an air classifier. Pin mill is more efficient than the ball mill for liberation. As a result, the MgO grade of concentrate was 47.1% with recovery of 51.51% for classified with 3,000rpm of air classifier for ground at 13,000rpm in pin mill.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.163-169
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• 2003

The vertical roller mill is the important machine grinding and mixing various crude materials in the manufacturing process of portland cement. Table liner is one of grinding elements of vertical roller mill and is subjected to the cyclic bending stress by rollers load and the centrifugal force by rotation of table. It demands $4{\times}10^7$ cycle but has $4{\times}10^6{\sim}8{\times}10^6$ cycle. It fractures at the edge of grinding path of outside roller. The repair expense for it amounts to 30% of total maintenance of vertical roller mill. Therefore, this study shows the fracture mechanism of table liner for vertical roller mill using HDM and fatigue analysis

• Journal of Biosystems Engineering
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• v.31 no.1 s.114
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• pp.33-38
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• 2006

This work was conducted to find the operating characteristics of an efficient wet grinding system designed to obtain fine rice husk ash powder. Once the rice husk was combusted and the thermal energy was recovered from the furnace, the ash was fed and pulverized in the grinding system resulting a fine powder to be used as a supplementary adding material to the portland cement. Grinding time (15, 30, 45 min), impeller speed (250, 500, 750 rpm), and mixed ratio (6.7, 8.4, 11.l, 20.9) were three operating factors examined for the performance of a wet-type stirred ball mill grinding system. For the operating conditions employed, mean diameter of fine ash powder, specific energy input, and grinding energy efficiency were in the range of $2.83{\sim}9.58{\mu}m,\;0.5{\sim}6.73kWh/kg,\;and\;0.51{\sim}3.27m^2/Wh$, respectively. With the wet-type stirred ball mill grinding system used in this study, the grinding energy efficiency decreased with the increase in total grinding time, impeller speed, and mixed ratio. The difference in specific surface area of powder linearly increased with logarithm in total number of impeller revolution and the grinding energy efficiency linearly decreased. Grinding time of 45 min, impeller speed of 500 rpm, and mixed ratio of 6.7 were chosen as the best operating condition. At this condition, mean particle diameter of the fine ash, grinding energy efficiency, grinding throughput, and specific energy input were $2.84{\mu}m,\;2.28m^2/Wh,\;0.17kg/h$, and 2.03kWh/kg, respectively. Wet fine grinding which generates no fly dust causing pollution and makes continuous operation easy, is appeared to be a promising solution to the automatization of rice husk ash grinding process.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.234.2-234.2
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• 2003

Recently, the need for ultra-fine particles, especially nano-sized particles has increased in the fields preparing raw powders such as pharmaceutical additive and high value added products in the Nano-Technology processes. Therefore, the research in ultra-fine grinding is very important, especially, in nanometer grinding. In the previous paper, a series of wet grinding experiments using grinding aids using a stirred ball mill have been performed on grinding rate constant based on grinding kinetics. (omitted)