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used ball mills | ball mills for sale | phoenix equipment

used ball mills | ball mills for sale | phoenix equipment

Why buy a brand new ball mill when we have high-quality used and refurbished ball mills for sale? Well-made industrial equipment from top manufacturers maintain their value and save your company or industry substantially.

Ball mills are a fundamental part of the manufacturing industry in the USA as well as around the world. Ball mills crush material into various sizes and extract resources from mined materials. Pebble mills are a type of ball mill and are also used to reduce the size of hard materials, down to 1 micron or less.

Because of their fairly simple design, ball mills and pebble mills are less likely to need costly repairs (unlike other crushing or extraction equipment) making them an attractive option for businesses on a budget.

Unused 24 x 41 Polysius EGL Ball Mill. Steel Lined. Twin 7MW Electric Motor Drives, 14MW/11kV Power Supply Unit. Twin Combiflex Fixed Speed Gear Drive. Auxiliary Drive Motors, Lubrication Unit Fixed Bearing and Lubrication Unit Floating Bearing, Frozen Charge Protection System, Vibration Sensors for COMBIFLEX, Dam Ring, Permanent installed Centrifuge for Fixed Bearing, Closed Circuit Chiller Unit, Insurance and Commissioning Spares, Special Tools. Qty 2 Available.

Used 11.5' diameter X 17' long ball mill. Manufactured by KVS (Kennedy Van Saun). 1000 HP open winding synchronous motor. Features trommel discharge and feed tank. Refurbished in 2013, which included installation of new oil jacking system, oil lube system for Babbitt bearings, new titanium steel water jet-machined discharge grates, and motor refurbishment. Set of new babbit bearings available. Previously operated as a closed circuit dry mill with grinding capacity of 40 metric tons per hour with output fineness of >80% passing 200 mesh. Motor operating speed of 15.8 RPM charged with approximately 78 tons of 1", 2" and 3" steel balls. Last used at a phosphate processing facility and in good condition.

Used 8' x 10' Epworth 200 HP jacketed steel ball mill, approximately 8' diameter x 10' long, jacketed chamber, gear and pinion driven with approximately 200 motor drive, on stands, Serial# K-0845.

Used 175HP Hosokawa Alpine Super Orion Continuous Ball mill. Model 195/495 CLKE. Alumina Oxide lined. 195 cm (76")inner diameter x 495 cm (194") long drum, periphery dry discharge with adjustable discharge openings, enclosed discharge housing, direct driven thru gearbox. 175HP 460 volt motor with VFD motor controller. Serial# C1198474. Built 2012.

Used 6' x 8' Paul Abbe jacketed 100 HP steel ball mill, approximately 6' diameter x 8' long, jacketed chamber, gear and pinion driven with approximately 100 motor drive, on stands.

Unused 5' diameter X 6' long Steel Lined Ball Mill, manufactured by Patterson Industries, Type D, non-jacketed, with AR400 steel liners. Includes 30 HP, 3 phase, 60 Hz, 230-460 V, 1725 RPM motor. Mill drive is integrally coupled to horizontal parallel shafted helical gear reducer. Continuous type, with product feeding through spiral inlet trunnion and exiting through the discharge end trunnion. Features cylinder manway access door for cleaning. Internal volume measures approximately 839 USG (112 CF). Mill shell is lined with (24) 1/4" thick liner plates, each head lined with (8) 3/8" thick pie-shaped liner plates. Mounted on stand with approximately 66" clearance between the mill cylinder and floor. Mills were intended for use in glass particle size reduction but were never installed. Manufactured in 2019, units are still in factory plastic wrap and in new condition. (Qty - 2 available)

Used 5 ft. dia. x 6 ft. (Approx 120 Cu.Ft) Patterson Pebble Mill. Alumina brick lining. On stand with 20 HP motor and gear reduced drive with brake. Bull gear and pinion. Babbit bearings. Door is polyurethane and has a drain with plug.

Used 4' x 5' (345 Gallon Total/210 Gallon Working) Ball Mill. Mfg Steveco. Steel Lining. Jacketed. 20 HP (460V/60Hz/3ph) Gear Reduced heavy duty drive on high stands. Solid door and discharge door.

Used Paul O. Abbe One Piece Ceramic Ball Mill, Model JM-300. Non-Jacketed chamber approximate 24.8" diameter x 39.5" long. Vessel volume 300 liter (79 gallons). Approximate 5" charge and discharge port with cover. Driven by a 3 HP, 3/60/208-230/460 volt 1760 rpm motor with a shaft mounted Sumitomo Model 203E-25 reducer. Approximate 32 rpm drum speed. Includes a control panel with an ABB drive. Mounted on a common carbon steel frame legs. Serial # 0830032JM. Built 2008.

Used 28 Gallon Paul O. Abbe Ceramic Jar / Ball Mill. Approximate 3.7 Cubic Feet. Approximate 20" diameter x 20" straight side. Includes motor and cage. Mounted on a carbon steel frame with safety cage.

Used 30 gallon Paul O. Abbe Jar Mill. Porcelain jar 21" diameter x 18" straight side. Driven by 1hp, 1/60/115/230 volt, 1740 rpm motor thru a reducer, ratio 9.3 to 1. Inlet & outlet with cover and clamp. Mounted on carbon steel legs with a discharge housing. Serial#84876

Used 25 Gallon Norton Chemical Process Products Jar Mill. Porcelain jar 20" diameter x 20" straight side. Driven by 1hp, 3/60/230/460 volt, 1730 rpm motor thru a reducer, no ratio. Inlet & outlet with cover and clamp. Mounted on carbon steel legs with a discharge housing. Serial# AV-83104.

Used 35.30 Gallon Paul O. Abbe Jar Mill. Model 5A Porcelain jar 22" diameter x 20" straight side. Driven by 1hp, 3/60/230/460 volt, 1745 rpm motor thru a reducer, ratio 25 to 1. Inlet & outlet with cover and clamp. Mounted on carbon steel legs with a discharge housing. Serial#A41563.

Unused 24 x 41 Polysius EGL Ball Mill. Steel Lined. Twin 7MW Electric Motor Drives, 14MW/11kV Power Supply Unit. Twin Combiflex Fixed Speed Gear Drive. Auxiliary Drive Motors, Lubrication Unit Fixed Bearing and Lubrication Unit Floating Bearing, Frozen Charge Protection System, Vibration Sensors for COMBIFLEX, Dam Ring, Permanent installed Centrifuge for Fixed Bearing, Closed Circuit Chiller Unit, Insurance and Commissioning Spares, Special Tools. Qty 2 Available.

Used 11.5' diameter X 17' long ball mill. Manufactured by KVS (Kennedy Van Saun). 1000 HP open winding synchronous motor. Features trommel discharge and feed tank. Refurbished in 2013, which included installation of new oil jacking system, oil lube system for Babbitt bearings, new titanium steel water jet-machined discharge grates, and motor refurbishment. Set of new babbit bearings available. Previously operated as a closed circuit dry mill with grinding capacity of 40 metric tons per hour with output fineness of >80% passing 200 mesh. Motor operating speed of 15.8 RPM charged with approximately 78 tons of 1", 2" and 3" steel balls. Last used at a phosphate processing facility and in good condition.

Used 8' x 10' Epworth 200 HP jacketed steel ball mill, approximately 8' diameter x 10' long, jacketed chamber, gear and pinion driven with approximately 200 motor drive, on stands, Serial# K-0845.

Used 175HP Hosokawa Alpine Super Orion Continuous Ball mill. Model 195/495 CLKE. Alumina Oxide lined. 195 cm (76")inner diameter x 495 cm (194") long drum, periphery dry discharge with adjustable discharge openings, enclosed discharge housing, direct driven thru gearbox. 175HP 460 volt motor with VFD motor controller. Serial# C1198474. Built 2012.

Used 6' x 8' Paul Abbe jacketed 100 HP steel ball mill, approximately 6' diameter x 8' long, jacketed chamber, gear and pinion driven with approximately 100 motor drive, on stands.

Unused 5' diameter X 6' long Steel Lined Ball Mill, manufactured by Patterson Industries, Type D, non-jacketed, with AR400 steel liners. Includes 30 HP, 3 phase, 60 Hz, 230-460 V, 1725 RPM motor. Mill drive is integrally coupled to horizontal parallel shafted helical gear reducer. Continuous type, with product feeding through spiral inlet trunnion and exiting through the discharge end trunnion. Features cylinder manway access door for cleaning. Internal volume measures approximately 839 USG (112 CF). Mill shell is lined with (24) 1/4" thick liner plates, each head lined with (8) 3/8" thick pie-shaped liner plates. Mounted on stand with approximately 66" clearance between the mill cylinder and floor. Mills were intended for use in glass particle size reduction but were never installed. Manufactured in 2019, units are still in factory plastic wrap and in new condition. (Qty - 2 available)

Used 5 ft. dia. x 6 ft. (Approx 120 Cu.Ft) Patterson Pebble Mill. Alumina brick lining. On stand with 20 HP motor and gear reduced drive with brake. Bull gear and pinion. Babbit bearings. Door is polyurethane and has a drain with plug.

Used 4' x 5' (345 Gallon Total/210 Gallon Working) Ball Mill. Mfg Steveco. Steel Lining. Jacketed. 20 HP (460V/60Hz/3ph) Gear Reduced heavy duty drive on high stands. Solid door and discharge door.

Used Paul O. Abbe One Piece Ceramic Ball Mill, Model JM-300. Non-Jacketed chamber approximate 24.8" diameter x 39.5" long. Vessel volume 300 liter (79 gallons). Approximate 5" charge and discharge port with cover. Driven by a 3 HP, 3/60/208-230/460 volt 1760 rpm motor with a shaft mounted Sumitomo Model 203E-25 reducer. Approximate 32 rpm drum speed. Includes a control panel with an ABB drive. Mounted on a common carbon steel frame legs. Serial # 0830032JM. Built 2008.

Used 28 Gallon Paul O. Abbe Ceramic Jar / Ball Mill. Approximate 3.7 Cubic Feet. Approximate 20" diameter x 20" straight side. Includes motor and cage. Mounted on a carbon steel frame with safety cage.

Used 30 gallon Paul O. Abbe Jar Mill. Porcelain jar 21" diameter x 18" straight side. Driven by 1hp, 1/60/115/230 volt, 1740 rpm motor thru a reducer, ratio 9.3 to 1. Inlet & outlet with cover and clamp. Mounted on carbon steel legs with a discharge housing. Serial#84876

Used 25 Gallon Norton Chemical Process Products Jar Mill. Porcelain jar 20" diameter x 20" straight side. Driven by 1hp, 3/60/230/460 volt, 1730 rpm motor thru a reducer, no ratio. Inlet & outlet with cover and clamp. Mounted on carbon steel legs with a discharge housing. Serial# AV-83104.

Used 35.30 Gallon Paul O. Abbe Jar Mill. Model 5A Porcelain jar 22" diameter x 20" straight side. Driven by 1hp, 3/60/230/460 volt, 1745 rpm motor thru a reducer, ratio 25 to 1. Inlet & outlet with cover and clamp. Mounted on carbon steel legs with a discharge housing. Serial#A41563.

Phoenix Equipment is a global supplier of used ball mills. We have new, used and reconditioned ball mills from leading manufacturers, including: Paul O. Abbe Retsch Epworth Patterson Netzsch Newell Dunford Marcy Denver FL Smidth Nordberg Allis Chalmers Metso Hardinge Kurimoto Iron Works Kobe-Allis Chalmers Stevenson Fuller-Traylor Steveco Western Machinery Marion Machine Makrum and more. Ball mills are used in a wide-range of industrial applications: cement processing, paint dyes and pigmentation processing, coal and ore processing, chemical processing and pyrotechnics, and many others. Ball milling has several key advantages over other systems: cost of the grinding medium and installation is generally low works for batch or continuous operation (as well as closed-circuit grinding) suitable for a wide range of materials simple design ensures less repairs Whether you are in the market for a used ball mill for your business or you have a pre-owned ball mill youd like to sell, USA-based Phoenix Equipment can help. Contact us today to learn more about what Phoenix can do for you. Related equipment: Agitators, Screen/Separators, Kilns and Calciners, Scales and Extruders. Fill out our quick and easy quote form for more information about our Ball Mills inventory.

Ball mills are used in a wide-range of industrial applications: cement processing, paint dyes and pigmentation processing, coal and ore processing, chemical processing and pyrotechnics, and many others.

Whether you are in the market for a used ball mill for your business or you have a pre-owned ball mill youd like to sell, USA-based Phoenix Equipment can help. Contact us today to learn more about what Phoenix can do for you.

Phoenix Equipment buys and sells used chemical process equipment and plants for relocation. Our industry focus includes process plants and machinery in the chemical, petrochemical, fertilizer, refining, gas processing, power generation, pharmaceutical and food manufacturing industries. We have extensive experience acquiring processing plants and process lines that require the execution of complex dismantlement, demolition and decommissioning projects. Based in Red Bank, New Jersey, USA, we have team members located in China, India, Germany and relationships throughout the world.

Why Use Phoenix for Your Plant Dismantling & Plant Relocation Needs A Common Plant Liquidation Scenario Your company has made the tough decision to close a plant. This plant was running for years, and the company paid a lot to have it built, paid everyones salaries, and maintained or even modernized all of the production assets over the plants life but the plant needs to be sold off for one reason or another. Your company has called upon you to recover as much dollar as you can to help keep the organization alive, and better yet, healthy, in what is a constant battle in the marketplace. Youve either: Have spent months, maybe even years trying to find a buyer that would operate the plant in place, without any success, while the plants assets lose value every passing day. Or, you cant sell it to another company, as you are one of the few suppliers of the product the plant makes, and you dont want to create a competitor, or improve a competitors position. Or, the plant is on leased propert

Hydrogenation: Major Applications Hydrogenation is a billion-dollar industry. Hydrogenating means to add hydrogen to something. According to Haldor Topsoe, hydrogenation comprises 48% of total hydrogen consumption, 44% of which is for hydrocracking and hydrotreating in refineries , and 4% for hydrogenation of unsaturated hydrocarbons (including hardening of edible oil) and of aromatics, hydrogenation of aldehydes and ketones (for instance oxo-products), and hydrogenation of nitrobezene (for manufacture of aniline). Hydrocracking & Hydrotreating Industrially, hydrotreating and hydrocracking are performed in down flow trickle bed reactors, where the gas and the liquid feed are sent concurrently through a fixed bed plug flow reactor. Although the flow pattern in the reactor can be reasonably approximated, the observed kinetics in such a trickle bed reactor are quite often affected by minor unplanned oscillations in the flow. How the gas and liquid collide and mix together affects the end prod

Thermoplastics A Focus on Polyethylene & Polypropylene Thermoplastics are a class of polymers, that with the application of heat, can be softened and melted, and can be processed either in the heat-softened state (e.g. by thermoforming) or in the liquid state (e.g. by extrusion and injection molding). Over 70% of the plastics used in the world are thermoplastics, and the two most commonly used thermoplastics are both olefins, compound made up of hydrogen and carbon that contains one or more pairs of carbon atoms linked by a double bond. These two olefins are polyethylene and polypropylene. Polyethylene Polyethylene is a tough, light, flexible synthetic resin made by polymerizing ethylene, chiefly used for plastic bags, food containers, and other packaging. It may be of low density or high density depending upon the process used in its manufacturing. It is resistant to moisture and most of the chemicals. It can be heat sealed and is flexible at room temperature (and low temperature), and in additional to its material properties,

roller mill jars | milling jars for sale | mse supplies mse supplies llc

roller mill jars | milling jars for sale | mse supplies mse supplies llc

Our grinding roller mill jars are available with simply clamp-and-roll designs, and their seals are always secure and tight. Industries which require high purity laboratory samples to be ground can make use of them. Our milling jar set includes the following:

Get in touch with us for a bulk requirement and we will be able to give you an attractive price quote. It makes great sense for companies to order these products in bulk. A number of top research labs are already ordering from us, so why delay any further? We will make every effort to keep trust intact with you.

china ball mill equipment manufacturer, rotary dryer, sand making machine supplier - zhengzhou hengxing heavy equipment co., ltd

china ball mill equipment manufacturer, rotary dryer, sand making machine supplier - zhengzhou hengxing heavy equipment co., ltd

Ball Mill Equipment, Rotary Dryer, Sand Making Machine manufacturer / supplier in China, offering Energy Saving Briquette Mesh Belt Dryer, Mini Sand Making Machine for Cobble Stone, Good Quality Dewatering Screen for Tailings with Polyurethane Screen and so on.

Zhengzhou Hengxing Heavy Equipment Co., Ltd. is a joint stock corporation integrating research and manufacture sale with the targt at the large and medium sized series of heavy equipment for mine machinery, wall materies, formed coal, metallurgy and etc. The company is located at No. 8 Hongye Road, West Hehuan Street, High-Tech Development Zone, Zhengzhou, China. Since establishment, our company has gathered a group of scientific elites with modernized management system and accurate production as well ...

chaeng+active lime production line+mine&cement industry+large production - xinxiang great wall machinery co., ltd - pdf catalogs | technical documentation | brochure

chaeng+active lime production line+mine&cement industry+large production - xinxiang great wall machinery co., ltd - pdf catalogs | technical documentation | brochure

CHAENG is attending the 32nd International Mining Exhibition, Acapulco, Mexico CHAENG is attending the 32nd International Mining Exhibition, Acapulco, Mexico. We sincerely invite all friends to come and visit and cooperate. With 60-year experience in equipment manufacturing, it's been formed a complete control system covering Engineering, Product manufacture, Marketing, Installation and After-sales services. Our products have been widely Spread in Chinese market and exported to America, Russia, Uzbekistan, Vietnam, Turkey, Iran, South Africa, and other countries with higher market popularity and reputation. Our products include slag grinding plant, active lime production line, cement clinker grinding station, vertical roller mill, ball mill, vertical lime kiln, rotary kiln, and large steel castings such as girth gear, kiln tyre, kiln supporting roller, Slag pot and so on. We sincerely invite all friends to come and visit and cooperate. CHAENG(xinxiang great wall machinery co., ltd) is glad to cooperate with all old and new clients from home and abroad to create brilliant future together!

ball mill - an overview | sciencedirect topics

ball mill - an overview | sciencedirect topics

The ball mill accepts the SAG or AG mill product. Ball mills give a controlled final grind and produce flotation feed of a uniform size. Ball mills tumble iron or steel balls with the ore. The balls are initially 510 cm diameter but gradually wear away as grinding of the ore proceeds. The feed to ball mills (dry basis) is typically 75 vol.-% ore and 25% steel.

The ball mill is operated in closed circuit with a particle-size measurement device and size-control cyclones. The cyclones send correct-size material on to flotation and direct oversize material back to the ball mill for further grinding.

Grinding elements in ball mills travel at different velocities. Therefore, collision force, direction and kinetic energy between two or more elements vary greatly within the ball charge. Frictional wear or rubbing forces act on the particles, as well as collision energy. These forces are derived from the rotational motion of the balls and movement of particles within the mill and contact zones of colliding balls.

By rotation of the mill body, due to friction between mill wall and balls, the latter rise in the direction of rotation till a helix angle does not exceed the angle of repose, whereupon, the balls roll down. Increasing of rotation rate leads to growth of the centrifugal force and the helix angle increases, correspondingly, till the component of weight strength of balls become larger than the centrifugal force. From this moment the balls are beginning to fall down, describing during falling certain parabolic curves (Figure 2.7). With the further increase of rotation rate, the centrifugal force may become so large that balls will turn together with the mill body without falling down. The critical speed n (rpm) when the balls are attached to the wall due to centrifugation:

where Dm is the mill diameter in meters. The optimum rotational speed is usually set at 6580% of the critical speed. These data are approximate and may not be valid for metal particles that tend to agglomerate by welding.

The degree of filling the mill with balls also influences productivity of the mill and milling efficiency. With excessive filling, the rising balls collide with falling ones. Generally, filling the mill by balls must not exceed 3035% of its volume.

The mill productivity also depends on many other factors: physical-chemical properties of feed material, filling of the mill by balls and their sizes, armor surface shape, speed of rotation, milling fineness and timely moving off of ground product.

where b.ap is the apparent density of the balls; l is the degree of filling of the mill by balls; n is revolutions per minute; 1, and 2 are coefficients of efficiency of electric engine and drive, respectively.

A feature of ball mills is their high specific energy consumption; a mill filled with balls, working idle, consumes approximately as much energy as at full-scale capacity, i.e. during grinding of material. Therefore, it is most disadvantageous to use a ball mill at less than full capacity.

The ball mill is a tumbling mill that uses steel balls as the grinding media. The length of the cylindrical shell is usually 11.5 times the shell diameter (Figure 8.11). The feed can be dry, with less than 3% moisture to minimize ball coating, or slurry containing 2040% water by weight. Ball mills are employed in either primary or secondary grinding applications. In primary applications, they receive their feed from crushers, and in secondary applications, they receive their feed from rod mills, AG mills, or SAG mills.

Ball mills are filled up to 40% with steel balls (with 3080mm diameter), which effectively grind the ore. The material that is to be ground fills the voids between the balls. The tumbling balls capture the particles in ball/ball or ball/liner events and load them to the point of fracture.

When hard pebbles rather than steel balls are used for the grinding media, the mills are known as pebble mills. As mentioned earlier, pebble mills are widely used in the North American taconite iron ore operations. Since the weight of pebbles per unit volume is 3555% of that of steel balls, and as the power input is directly proportional to the volume weight of the grinding medium, the power input and capacity of pebble mills are correspondingly lower. Thus, in a given grinding circuit, for a certain feed rate, a pebble mill would be much larger than a ball mill, with correspondingly a higher capital cost. However, the increase in capital cost is justified economically by a reduction in operating cost attributed to the elimination of steel grinding media.

In general, ball mills can be operated either wet or dry and are capable of producing products in the order of 100m. This represents reduction ratios of as great as 100. Very large tonnages can be ground with these ball mills because they are very effective material handling devices. Ball mills are rated by power rather than capacity. Today, the largest ball mill in operation is 8.53m diameter and 13.41m long with a corresponding motor power of 22MW (Toromocho, private communications).

Planetary ball mills. A planetary ball mill consists of at least one grinding jar, which is arranged eccentrically on a so-called sun wheel. The direction of movement of the sun wheel is opposite to that of the grinding jars according to a fixed ratio. The grinding balls in the grinding jars are subjected to superimposed rotational movements. The jars are moved around their own axis and, in the opposite direction, around the axis of the sun wheel at uniform speed and uniform rotation ratios. The result is that the superimposition of the centrifugal forces changes constantly (Coriolis motion). The grinding balls describe a semicircular movement, separate from the inside wall, and collide with the opposite surface at high impact energy. The difference in speeds produces an interaction between frictional and impact forces, which releases high dynamic energies. The interplay between these forces produces the high and very effective degree of size reduction of the planetary ball mill. Planetary ball mills are smaller than common ball mills, and are mainly used in laboratories for grinding sample material down to very small sizes.

Vibration mill. Twin- and three-tube vibrating mills are driven by an unbalanced drive. The entire filling of the grinding cylinders, which comprises the grinding media and the feed material, constantly receives impulses from the circular vibrations in the body of the mill. The grinding action itself is produced by the rotation of the grinding media in the opposite direction to the driving rotation and by continuous head-on collisions of the grinding media. The residence time of the material contained in the grinding cylinders is determined by the quantity of the flowing material. The residence time can also be influenced by using damming devices. The sample passes through the grinding cylinders in a helical curve and slides down from the inflow to the outflow. The high degree of fineness achieved is the result of this long grinding procedure. Continuous feeding is carried out by vibrating feeders, rotary valves, or conveyor screws. The product is subsequently conveyed either pneumatically or mechanically. They are basically used to homogenize food and feed.

CryoGrinder. As small samples (100 mg or <20 ml) are difficult to recover from a standard mortar and pestle, the CryoGrinder serves as an alternative. The CryoGrinder is a miniature mortar shaped as a small well and a tightly fitting pestle. The CryoGrinder is prechilled, then samples are added to the well and ground by a handheld cordless screwdriver. The homogenization and collection of the sample is highly efficient. In environmental analysis, this system is used when very small samples are available, such as small organisms or organs (brains, hepatopancreas, etc.).

The vibratory ball mill is another kind of high-energy ball mill that is used mainly for preparing amorphous alloys. The vials capacities in the vibratory mills are smaller (about 10 ml in volume) compared to the previous types of mills. In this mill, the charge of the powder and milling tools are agitated in three perpendicular directions (Fig. 1.6) at very high speed, as high as 1200 rpm.

Another type of the vibratory ball mill, which is used at the van der Waals-Zeeman Laboratory, consists of a stainless steel vial with a hardened steel bottom, and a single hardened steel ball of 6 cm in diameter (Fig. 1.7).

The mill is evacuated during milling to a pressure of 106 Torr, in order to avoid reactions with a gas atmosphere.[44] Subsequently, this mill is suitable for mechanical alloying of some special systems that are highly reactive with the surrounding atmosphere, such as rare earth elements.

A ball mill is a relatively simple apparatus in which the motion of the reactor, or of a part of it, induces a series of collisions of balls with each other and with the reactor walls (Suryanarayana, 2001). At each collision, a fraction of the powder inside the reactor is trapped between the colliding surfaces of the milling tools and submitted to a mechanical load at relatively high strain rates (Suryanarayana, 2001). This load generates a local nonhydrostatic mechanical stress at every point of contact between any pair of powder particles. The specific features of the deformation processes induced by these stresses depend on the intensity of the mechanical stresses themselves, on the details of the powder particle arrangement, that is on the topology of the contact network, and on the physical and chemical properties of powders (Martin et al., 2003; Delogu, 2008a). At the end of any given collision event, the powder that has been trapped is remixed with the powder that has not undergone this process. Correspondingly, at any instant in the mechanical processing, the whole powder charge includes fractions of powder that have undergone a different number of collisions.

The individual reactive processes at the perturbed interface between metallic elements are expected to occur on timescales that are, at most, comparable with the collision duration (Hammerberg et al., 1998; Urakaev and Boldyrev, 2000; Lund and Schuh, 2003; Delogu and Cocco, 2005a,b). Therefore, unless the ball mill is characterized by unusually high rates of powder mixing and frequency of collisions, reactive events initiated by local deformation processes at a given collision are not affected by a successive collision. Indeed, the time interval between successive collisions is significantly longer than the time period required by local structural perturbations for full relaxation (Hammerberg et al., 1998; Urakaev and Boldyrev, 2000; Lund and Schuh, 2003; Delogu and Cocco, 2005a,b).

These few considerations suffice to point out the two fundamental features of powder processing by ball milling, which in turn govern the MA processes in ball mills. First, mechanical processing by ball milling is a discrete processing method. Second, it has statistical character. All of this has important consequences for the study of the kinetics of MA processes. The fact that local deformation events are connected to individual collisions suggests that absolute time is not an appropriate reference quantity to describe mechanically induced phase transformations. Such a description should rather be made as a function of the number of collisions (Delogu et al., 2004). A satisfactory description of the MA kinetics must also account for the intrinsic statistical character of powder processing by ball milling. The amount of powder trapped in any given collision, at the end of collision is indeed substantially remixed with the other powder in the reactor. It follows that the same amount, or a fraction of it, could at least in principle be trapped again in the successive collision.

This is undoubtedly a difficult aspect to take into account in a mathematical description of MA kinetics. There are at least two extreme cases to consider. On the one hand, it could be assumed that the powder trapped in a given collision cannot be trapped in the successive one. On the other, it could be assumed that powder mixing is ideal and that the amount of powder trapped at a given collision has the same probability of being processed in the successive collision. Both these cases allow the development of a mathematical model able to describe the relationship between apparent kinetics and individual collision events. However, the latter assumption seems to be more reliable than the former one, at least for commercial mills characterized by relatively complex displacement in the reactor (Manai et al., 2001, 2004).

A further obvious condition for the successful development of a mathematical description of MA processes is the one related to the uniformity of collision regimes. More specifically, it is highly desirable that the powders trapped at impact always experience the same conditions. This requires the control of the ball dynamics inside the reactor, which can be approximately obtained by using a single milling ball and an amount of powder large enough to assure inelastic impact conditions (Manai et al., 2001, 2004; Delogu et al., 2004). In fact, the use of a single milling ball avoids impacts between balls, which have a remarkable disordering effect on the ball dynamics, whereas inelastic impact conditions permit the establishment of regular and periodic ball dynamics (Manai et al., 2001, 2004; Delogu et al., 2004).

All of the above assumptions and observations represent the basis and guidelines for the development of the mathematical model briefly outlined in the following. It has been successfully applied to the case of a Spex Mixer/ Mill mod. 8000, but the same approach can, in principle, be used for other ball mills.

The Planetary ball mills are the most popular mills used in MM, MA, and MD scientific researches for synthesizing almost all of the materials presented in Figure 1.1. In this type of mill, the milling media have considerably high energy, because milling stock and balls come off the inner wall of the vial (milling bowl or vial) and the effective centrifugal force reaches up to 20 times gravitational acceleration.

The centrifugal forces caused by the rotation of the supporting disc and autonomous turning of the vial act on the milling charge (balls and powders). Since the turning directions of the supporting disc and the vial are opposite, the centrifugal forces alternately are synchronized and opposite. Therefore, the milling media and the charged powders alternatively roll on the inner wall of the vial, and are lifted and thrown off across the bowl at high speed, as schematically presented in Figure 2.17.

However, there are some companies in the world who manufacture and sell number of planetary-type ball mills; Fritsch GmbH (www.fritsch-milling.com) and Retsch (http://www.retsch.com) are considered to be the oldest and principal companies in this area.

Fritsch produces different types of planetary ball mills with different capacities and rotation speeds. Perhaps, Fritsch Pulverisette P5 (Figure 2.18(a)) and Fritsch Pulverisette P6 (Figure 2.18(b)) are the most popular models of Fritsch planetary ball mills. A variety of vials and balls made of different materials with different capacities, starting from 80ml up to 500ml, are available for the Fritsch Pulverisette planetary ball mills; these include tempered steel, stainless steel, tungsten carbide, agate, sintered corundum, silicon nitride, and zirconium oxide. Figure 2.19 presents 80ml-tempered steel vial (a) and 500ml-agate vials (b) together with their milling media that are made of the same materials.

Figure 2.18. Photographs of Fritsch planetary-type high-energy ball mill of (a) Pulverisette P5 and (b) Pulverisette P6. The equipment is housed in the Nanotechnology Laboratory, Energy and Building Research Center (EBRC), Kuwait Institute for Scientific Research (KISR).

Figure 2.19. Photographs of the vials used for Fritsch planetary ball mills with capacity of (a) 80ml and (b) 500ml. The vials and the balls shown in (a) and (b) are made of tempered steel agate materials, respectively (Nanotechnology Laboratory, Energy and Building Research Center (EBRC), Kuwait Institute for Scientific Research (KISR)).

More recently and in year 2011, Fritsch GmbH (http://www.fritsch-milling.com) introduced a new high-speed and versatile planetary ball mill called Planetary Micro Mill PULVERISETTE 7 (Figure 2.20). The company claims this new ball mill will be helpful to enable extreme high-energy ball milling at rotational speed reaching to 1,100rpm. This allows the new mill to achieve sensational centrifugal accelerations up to 95 times Earth gravity. They also mentioned that the energy application resulted from this new machine is about 150% greater than the classic planetary mills. Accordingly, it is expected that this new milling machine will enable the researchers to get their milled powders in short ball-milling time with fine powder particle sizes that can reach to be less than 1m in diameter. The vials available for this new type of mill have sizes of 20, 45, and 80ml. Both the vials and balls can be made of the same materials, which are used in the manufacture of large vials used for the classic Fritsch planetary ball mills, as shown in the previous text.

Retsch has also produced a number of capable high-energy planetary ball mills with different capacities (http://www.retsch.com/products/milling/planetary-ball-mills/); namely Planetary Ball Mill PM 100 (Figure 2.21(a)), Planetary Ball Mill PM 100 CM, Planetary Ball Mill PM 200, and Planetary Ball Mill PM 400 (Figure 2.21(b)). Like Fritsch, Retsch offers high-quality ball-milling vials with different capacities (12, 25, 50, 50, 125, 250, and 500ml) and balls of different diameters (540mm), as exemplified in Figure 2.22. These milling tools can be made of hardened steel as well as other different materials such as carbides, nitrides, and oxides.

Figure 2.21. Photographs of Retsch planetary-type high-energy ball mill of (a) PM 100 and (b) PM 400. The equipment is housed in the Nanotechnology Laboratory, Energy and Building Research Center (EBRC), Kuwait Institute for Scientific Research (KISR).

Figure 2.22. Photographs of the vials used for Retsch planetary ball mills with capacity of (a) 80ml, (b) 250ml, and (c) 500ml. The vials and the balls shown are made of tempered steel (Nanotechnology Laboratory, Energy and Building Research Center (EBRC), Kuwait Institute for Scientific Research (KISR)).

Both Fritsch and Retsch companies have offered special types of vials that allow monitoring and measure the gas pressure and temperature inside the vial during the high-energy planetary ball-milling process. Moreover, these vials allow milling the powders under inert (e.g., argon or helium) or reactive gas (e.g., hydrogen or nitrogen) with a maximum gas pressure of 500kPa (5bar). It is worth mentioning here that such a development made on the vials design allows the users and researchers to monitor the progress tackled during the MA and MD processes by following up the phase transformations and heat realizing upon RBM, where the interaction of the gas used with the freshly created surfaces of the powders during milling (adsorption, absorption, desorption, and decomposition) can be monitored. Furthermore, the data of the temperature and pressure driven upon using this system is very helpful when the ball mills are used for the formation of stable (e.g., intermetallic compounds) and metastable (e.g., amorphous and nanocrystalline materials) phases. In addition, measuring the vial temperature during blank (without samples) high-energy ball mill can be used as an indication to realize the effects of friction, impact, and conversion processes.

More recently, Evico-magnetics (www.evico-magnetics.de) has manufactured an extraordinary high-pressure milling vial with gas-temperature-monitoring (GTM) system. Likewise both system produced by Fritsch and Retsch, the developed system produced by Evico-magnetics, allowing RBM but at very high gas pressure that can reach to 15,000kPa (150bar). In addition, it allows in situ monitoring of temperature and of pressure by incorporating GTM. The vials, which can be used with any planetary mills, are made of hardened steel with capacity up to 220ml. The manufacturer offers also two-channel system for simultaneous use of two milling vials.

Using different ball mills as examples, it has been shown that, on the basis of the theory of glancing collision of rigid bodies, the theoretical calculation of tPT conditions and the kinetics of mechanochemical processes are possible for the reactors that are intended to perform different physicochemical processes during mechanical treatment of solids. According to the calculations, the physicochemical effect of mechanochemical reactors is due to short-time impulses of pressure (P = ~ 10101011 dyn cm2) with shift, and temperature T(x, t). The highest temperature impulse T ~ 103 K are caused by the dry friction phenomenon.

Typical spatial and time parameters of the impactfriction interaction of the particles with a size R ~ 104 cm are as follows: localization region, x ~ 106 cm; time, t ~ 108 s. On the basis of the obtained theoretical results, the effect of short-time contact fusion of particles treated in various comminuting devices can play a key role in the mechanism of activation and chemical reactions for wide range of mechanochemical processes. This role involves several aspects, that is, the very fact of contact fusion transforms the solid phase process onto another qualitative level, judging from the mass transfer coefficients. The spatial and time characteristics of the fused zone are such that quenching of non-equilibrium defects and intermediate products of chemical reactions occurs; solidification of the fused zone near the contact point results in the formation of a nanocrystal or nanoamor- phous state. The calculation models considered above and the kinetic equations obtained using them allow quantitative ab initio estimates of rate constants to be performed for any specific processes of mechanical activation and chemical transformation of the substances in ball mills.

There are two classes of ball mills: planetary and mixer (also called swing) mill. The terms high-speed vibration milling (HSVM), high-speed ball milling (HSBM), and planetary ball mill (PBM) are often used. The commercial apparatus are PBMs Fritsch P-5 and Fritsch Pulverisettes 6 and 7 classic line, the Retsch shaker (or mixer) mills ZM1, MM200, MM400, AS200, the Spex 8000, 6750 freezer/mill SPEX CertiPrep, and the SWH-0.4 vibrational ball mill. In some instances temperature controlled apparatus were used (58MI1); freezer/mills were used in some rare cases (13MOP1824).

The balls are made of stainless steel, agate (SiO2), zirconium oxide (ZrO2), or silicon nitride (Si3N). The use of stainless steel will contaminate the samples with steel particles and this is a problem both for solid-state NMR and for drug purity.

However, there are many types of ball mills (see Chapter 2 for more details), such as drum ball mills, jet ball mills, bead-mills, roller ball mills, vibration ball mills, and planetary ball mills, they can be grouped or classified into two types according to their rotation speed, as follows: (i) high-energy ball mills and (ii) low-energy ball mills. Table 3.1 presents characteristics and comparison between three types of ball mills (attritors, vibratory mills, planetary ball mills and roller mills) that are intensively used on MA, MD, and MM techniques.

In fact, choosing the right ball mill depends on the objectives of the process and the sort of materials (hard, brittle, ductile, etc.) that will be subjecting to the ball-milling process. For example, the characteristics and properties of those ball mills used for reduction in the particle size of the starting materials via top-down approach, or so-called mechanical milling (MM process), or for mechanically induced solid-state mixing for fabrications of composite and nanocomposite powders may differ widely from those mills used for achieving mechanically induced solid-state reaction (MISSR) between the starting reactant materials of elemental powders (MA process), or for tackling dramatic phase transformation changes on the structure of the starting materials (MD). Most of the ball mills in the market can be employed for different purposes and for preparing of wide range of new materials.

Martinez-Sanchez et al. [4] have pointed out that employing of high-energy ball mills not only contaminates the milled amorphous powders with significant volume fractions of impurities that come from milling media that move at high velocity, but it also affects the stability and crystallization properties of the formed amorphous phase. They have proved that the properties of the formed amorphous phase (Mo53Ni47) powder depends on the type of the ball-mill equipment (SPEX 8000D Mixer/Mill and Zoz Simoloter mill) used in their important investigations. This was indicated by the high contamination content of oxygen on the amorphous powders prepared by SPEX 8000D Mixer/Mill, when compared with the corresponding amorphous powders prepared by Zoz Simoloter mill. Accordingly, they have attributed the poor stabilities, indexed by the crystallization temperature of the amorphous phase formed by SPEX 8000D Mixer/Mill to the presence of foreign matter (impurities).

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