Ball Mill

High-energy ball milling is utilized in creating microstructural changes (such as change in lattice param- eter, lattice strain) within micro-ceria, which were quanti- fied using line profile analysis by X-ray diffraction. Crystallite size significantly decreased from 85 to 11 nm when subjected to 4 h of high-energy ball milling, and then remained same with increase in milling duration (up to 16 h of milling). Three different methods, namely Nelson– Riley function, Cohen’s method, and Pawley fitting, were used to calculate the lattice parameter and a lattice expansion from 5.4082 to 5.4147 A ̊ was observed for a duration of 0 up to 12 h. The effect of milling on genera- tion of residual strain and the probability of stacking fault in affecting the lattice parameter are delineated in the current work. Non-monotonic change of lattice parameter with saturation of crystallite size is attributed to the vacancy-induced stresses that generate at inter-crystallite regions and render excessive free volume during high-en- ergy ball milling.

This paper is concerned with the design criteria of screw feeders: a non proper design and selection of this device, which is present in large part of industrial processes, could mean poor performances, excessive power, severe wear of plant and degradation of the conveyed material.

Dalam proses pengolahan partikel mungkin ada sejumlah bahan yang memerlukan beberapa bentuk pengolahan. Bahan-bahan tersebut termasuk biji-bijian sereal kasar, jagung yang membutuhkan pengurangan ukuran partikel yang akan meningkatkan kinerja bahan dan meningkatkan nilai gizi. Ada banyak cara untuk mencapai hal ini pengurangan ukuran partikel, di sini kita melihat dengan menggunakan Hammer Miils, Roller Mills, Blow Mills.

In June 1998, the world's largest grinding mill, the 40 ft (12.2 m) diameter 20 MW Cadia gearless SAG mill, was commissioned. This was a leap of over 40% above the largest operating SAG mill. A significant saving in capital cost gave the incentive necessary for a single mill line at Cadia, resulting in the selection of the 40 ft (12.2 m) diameter mill. Now, after 18 months of operation, this paper will review the significant items involved in the development, design, manufacture, installation, and operation of this mill.

The influence of both formulation and processing variables on the physical characteristics of milk chocolate has been studied during milling with a pilot ball mill. Nine experimental millings were carried out varying the type of dried milk used (roller, high free fat and spray-dried milk) and the time of lecithin and dried milk addition during the refining process. For the samples collected during 2 h of milling, particle size, moisture, Casson plastic viscosity and yield value were evaluated. In all the experiments, the solid particle size was effectively reduced during the first 120 min of refining; after this time the particle size reduction assumed an asymptotic trend. The addition of lecithin at the beginning of the refining kept the viscosity low and constant throughout the process, thus allowing the addition of milk from the start of the process, regardless of the technology adopted for milk drying.

Dünyada ve ülkemizde sönmüş kireç; şehir sularının ıslahı, evsel ve endüstriyel atık suların arıtımı, atık çamur muamelesi, baca gazı desülfürizasyonu, katı çöp ıslahı vs. gibi çevre kirliliğinin önlenmesinde ve rehabilitasyonunda gittikçe yaygın bir şekilde kullanılmaya başlamıştır. Gelişen teknoloji ile birlikte kimya, çevre, kozmetik, gıda, zirai uygulamalar, kauçuk, plastik gibi endüstriyel alanlarda ve termik santrallerde çok ince (<10 µm) ve süper ince (<1 µm ) boyutlardaki kirece olan talep artmıştır. Bu nedenle, kirecin mikronize boyuta ufalanması yani boyut küçültme işlemine tabi tutulması gerekmektedir. Bu çalışmada Adaçal Kireç fabrikasında (Emirdağ-Afyonkarahisar) üretilen 1 mm boyutundaki sönmüş kireci seramik bilyalı değirmende 10 µm altına öğütebilmek için kuru öğütme işlem parametreleri optimize edilmiş, mikronize kirecin tane boyutu, beyazlık, porozite, aktivasyon, özgül yüzey alanı, yığın yoğunluğu gibi fiziksel ve fiziko-kimyasal özelikleri değirmene beslenen sönmüş kirecin özellikleriyle karşılaştırılmıştır. Değirmen kritik hızı, bilya şarjı, malzeme şarjı ve öğütme süresinin optimizasyonu sonucunda, besleme boyutu 1 mm olan sönmüş kirecin ancak %57’si 10 µm altına indirilebilmiş, öğütmede etkin parametrelerin bilya şarjı ve öğütme süresi olduğu belirlenmiştir.

Actualmente existe en el trasporte público la necesidad de reemplazar constantemente las pastas de freno debido principalmente
al factor de desgaste y por razones de seguridad. En este trabajo se propone crear las bases del diseño general de una máquina prototipo capaz
de re-utilizar y reducir el tamaño de las pastas de freno del transporte público que están fuera de uso para ser empleadas como agente principal
en una mezcla pastosa. Esta pasta se utilizará como material aislante en construcciones, recubrimiento de paredes y techos, así mismo en la
elaboración de pavimentación en base sólida de calles. Para llevar a cabo esta propuesta se hace uso del método de Bond con el objetivo de
estimar las dimensiones iniciales del molino y la potencia necesaria, mediante la creación de un programa numérico BM-Crush, evitando con
esto construir molinos pilotos hasta donde esto es posible. Entre los principales resultados se obtiene la metodología general para calcular la
potencia mecánica y las dimensiones necesarias del molino con base a cualquier cambio en las condiciones iniciales de operación, así como
la distribución de los medios moledores y sus dimensionamiento. Se estima la velocidad crítica, estableciéndose con base en esto la velocidad
optima con la que debe girar el molino de bolas.

The polycrystalline samples of Ba-modified Pb(Fe1/2Nb1/2)O3 (i.e., (Pb1-xBax)(Fe1/2Nb1/2)O3 PBFN, with x=0,0.05,0.07) were synthesized by a mechanosynthesis (i.e., high-energy ball milling) route followed by a mixed oxide method. Structural analysis provides the information on formation of single-phase orthorhombic structure on substitution of a small amount (x=0.07) of Ba at the Pb-site of Pb(Fe0.50Nb0.50)O3 (PFN). The ferroelectric-paraelectric phase transition in PFN was observed at 383 K, which decreases on increasing Ba-concentration in PBFN. Detailed studies of dielectric properties of PBFW show the following: (i) diffuse phase transition, (ii) low loss tangent, (iii) low activation energy, and (iv) low frequency dielectric dispersion. An anomaly in the ac conductivity was found very close to phase transition temperature. The activation energy is found to decrease from 0.19 to 0.01 eV on increasing Ba-concentration to 7% (x=0.07). Temperature field-dependent magnetization measurements of all the samples showed antiferromagnetic transition at ˜15 K (for x=0.07). PBFN sample showed a slight increase in the coercivity (i.e., from 400 Oe (PFN) to 500 Oe (PBFN, for x=0.07) at 2 K.

Three different routes were used to fabricate ceramic particle dispersed epoxy composites. Only the wet ball-milling technique was found to be effective for homogeneous dispersion of ceramic particles. Mechanical properties were evaluated for the composites fabricated by ...

Nanophase materials can be synthesized by high energy milling. However, processing of large quantities finds a limitation in the devices available commercially, which are usually designed mainly for comminution and for laboratory-scale operations. We propose the design of a high energy, high capacity ball-mill which can be easily scaled up. An experimental device capable of processing up to about 250 g of powders with about 5 kg of balls has been realized. Impact velocities of about 3.5 m s−1 has been measured with operating frequencies of 17 Hz. The synthesis of nanophase iron carbides (assumed as a test system) is shown to be feasible with the new mill, with kinetics comparable with the best obtained in a Spex mill.

Objective: The main purpose of this paper is to present a new method of predicting clinical performance using mechanical loading in a ball mill.

Methods: A series of four experiments (two involving a hybrid composite and one each on orthodontic brackets and bands) is described in which the ball mill was used to subject specimens to mechanical fatigue.

Results: A reproducibility study using composite beam specimens showed no significant difference between the Mean Survival Time (MST) in all the three experimental runs (P = 0.42). When subjected to thermal cycling, the MST of the cycled group was 155.0 min compared to 247.0 min fur the control group (P < 0.01). The MST of untreated and sandblasted brackets was 7.9 h and 14 h respectively (P < 0.01). There is also a significant difference (P < 0.001) in the MST of sandblasted bands when compared to the untreated bands.

Conclusions: The ball mill proved to be a convenient and reproducible means of producing mechanical fatigue and may be useful in predicting the clinical performance of dental materials.

BACKGROUND: The porous structure generated during frying influences oil absorption and textural qualities. The alteration in physical properties of wheat flour is suspected to affect the structure formation. The present study investigated the effect of physicochemical changes in wheat flour by the ball-milling process on structure formation and consequently oil absorption of a fried wheat flour batter model.RESULTS: Batter models containing 600 g kg−1 moisture were made of 0–10 h ball-milled wheat flour and then fried in frying oil at 150 °C for 1–7 min. The samples made of milled flour possess larger pores and exhibit lower oil absorption than sample made of 0 h milled flour. The fracture force of a fried sample prepared from 5 and 10 h milled flour is lower than that of a sample prepared from 0 h milled flour.CONCLUSION: The decrease in glass transition temperature (Tg) and melting temperature (Tm) of milled flour affect the microstructure formation in the fried wheat flour batter. The microstructure is responsible for oil absorption and fracturability in fried food. The samples made of flour of longer ball-milling time have lower oil absorption and higher crispness. Ball-milling may be a tool to produce mechanically modified wheat flour which can reduce oil absorption for fried batter. Copyright © 2009 Society of Chemical Industry

We studied a nanocrystalline AlCrCuFeNiZn high-entropy alloy synthesized by ball milling followed by hot compaction at
600 C for 15 min at 650 MPa. X-ray diffraction reveals that the mechanically alloyed powder consists of a solid-solution body-centered cubic (bcc) matrix containing 12 vol.% face-centered cubic (fcc) phase. After hot compaction, it consists of 60 vol.% bcc and 40 vol.% fcc. Composition analysis by atom probe tomography shows that the material is not a homogeneous fcc–bcc solid solution but instead a composite of bcc structured Ni–Al-, Cr–Fe- and Fe–Cr-based regions and of fcc Cu–Zn-based regions. The Cu–Zn-rich phase has 30 at.% Zn a-brass composition. It segregates predominantly along grain boundaries thereby stabilizing the nanocrystalline microstructure and preventing grain growth. The Cr- and Fe-rich bcc regions were presumably formed by spinodal decomposition of a Cr–Fe phase that was inherited from the hot compacted state. The Ni–Al phase remains stable even after hot compaction and forms the dominant bcc matrix phase. The crystallite sizes are in the range of 20–30 nm as determined by transmission electron microscopy. The hot compacted alloy exhibited very high hardness of 870 ± 10 HV. The results reveal that phase decomposition rather than homogeneous mixing is prevalent in this alloy. Hence, our current observations fail to justify the present high-entropy alloy design concept. Therefore, a strategy guided more by structure and thermodynamics for designing high-entropy alloys is encouraged as a pathway towards exploiting the solid-solution and stability idea inherent in this concept."