Milling planetary mills

Yet here is another approach that, in this case, avoids solvent altogether, and leads to rapid and ligand-free cycloaddition reactions run in a planetary ball mill (e.g., see http //www.fritsch-milling.com/products/milling/planetary-mills/pulverisette-7-classic-line/). High conversions and selectivities are to be expected using Cu(OAc)2 in catalytic amounts (5 mol%), with reaction times on the order of only 10 minutes. ... 

Twin shell Vibratory pehhle mill tiirretf Vertical screw planetary types Cage mill Screw feeders... 

Planetary Ball Milling This is a method of increasing the gravitational force acting on balls in a ball mill. For example, refractoiy metals and carbides can be ground to 1 to 2.6 [Lm in 5 to 20 min in an apparatus capable of applying a centrifugal force of 10 to 50 G. [Dobrovol sldi, Poroshk. MetalL, 7(6), 1-7 (1967)]. 

Pulverit planetaiy mills are available from Geoscience Inc. Highspeed planetary-baU mills can be used to perform rapid tests to sinmlate ball milhng of materials [Vock, DECHEMA-Monogr, 69, HI-8 (1972)]. The size of high-speed mills will be much smaller than the size of same-capacity ball mills [Bradley, S. Afr Mech. Eng., 22, 129 (1972)]. 

Division of Geological and Planetary Sciences, California Institute of Technology, 1201 East California Street, Pasadena, CA 91125 and tLinus Pauling Institute of Science and Medicine, 440 Page Mill Road, Palo Alto. CA 94306... 

Ball, planetary-centrifugal, vibratory or ultrasonic mills are used for milling TiB2 and ZrBj powders. The milling elements are balls of cemented carbide (WC-Co) or ball-bearing steel. 

Planetary micromill Pulverisette 7, vibration micro pulverizer, Pulverisette 0, rotary speed mill, Pulverisette 14 Fritsch GmbH Laborgeraetebau Industriesstrasse 8 D-6580 Idar Oberstein Germany... 

The S-form can be obtained by treating Copper Phthalocyanine Blue in benzene or toluene with aqueous sulfuric acid in the presence of a surfactant [21], The e-phase is produced by comminution of the a-, 7-, or 8-modification, for instance in a planetary ball mill. The mill base is then aftertreated in an organic solvent at elevated temperature. It is important to realize that the temperature, depending on the solvent, must be kept below the transition temperature at which the e-phase converts to the (3-modification (30 to 160°C). The e-modification is made best from the 7-phase, and the most preferred solvents are alcohols [22], For the industrially hitherto insignificant tt, X, and R-forms of Copper Phthalocyanine Blue (see [1], Vol. II, 34-35). 

A serious limitation of the ball or tube mill is that it operates effectively only below its critical speed, as given by equation 2.10. In the planetary mill, described by Bradley et alS2y>, this constraint is obviated by rotating the mill simultaneously about its own axis and about an axis of gyration, as shown in Figure 2.32. In practice, several cylinders are incorporated in the machine, all rotating about the same axis of gyration. 

It is possible to achieve accelerations up to about 15g in practical operation. For further details of the operation of the planetary mill, reference may be made to Bradley et al.<23> and Kitschen et al.<24) The planetary mill is used for the preparation of stabilised slurries of coal in both oil and water, and it can also handle paste-like materials. 

Powders of zirconia and yttria were alloyed in a Fritsch planetary microball mill Pulverisette 7, as reported previously [13,14]. The resulting specimens were examined by XRD, TEM, SAED and HRTEM with EDS. 

Lyophilized copolymer was ground down to colloidal dimensions (<1 iJim) using a laboratory planetary mill (Pulverisette, Fritsch GmbH). A 110-mg sample of copolymer powder, 20 mg of bovine insulin, and 20 mg of GOD were mixed, and the mixture was compressed into a disk-shaped matrix of 5-mm thickness and 15-mm diameter. 

Tumbler, jar, drum, or cannon ball mills Szegvari attritor vertical mills and other vertical stirred ball mills Planetary Fritsch and Retsch model mills Shaker (vibratory) SPEX model mills... 

Fig. 1.4 Planetary miU vial with antenna mounted on cover equipped with temperature and pressure sensors for GTP wireless monitoring gas conditions during milling...

At this frequency of impacts the energy transferred to the powder would be comparable with that achieved in a planetary ball mill. The milling cylinder suitable for reactive milling is shown in Fig. 1.8. 

There are other advantages of employing magnetic ball mills besides the control of mechanical milling modes. Since the centrifugal force becomes a secondary factor in milling, and the reactor shell rotates at low RPM, contamination from balls and shell wear is lower than in a vibrational or a planetary mill there is less ball wear involved and contaminations with Fe from steel become less of the problem. Also lower rotations and uniaxial movement of reactors paced on horizontal axle allow... 

Elansari et al. [201] developed a novel method of synthesizing alkali metal hydrides Na, KH, RbH, and CsH by reactive mechanical milling of pure alkaline metals under hydrogen pressure up to 30 bars in a planetary mill (Retsch PM 400). The reaction proceeds in 16 h and gives 3-15 g of very pure alkali metal hydride with FCC crystal structure (space group Fm3m). 

Figure 7.11 Some basic types of roll arrangements (a) two-high, (b) three-high, (c) four-high, (d) cluster, (e) tandem rolling with three stands, and (f) planetary milling. McGraw-Hill Encyclopedia of Science and Technology, Vol. 11, 8th ed., p. 54. Copyright 1997 by McGraw-HiU.

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