Ball milling efficiency

Ball Mill Studies. II. Thermal determination of ball-mill efficiency. Am. Inst. Mining Mel. Eng. Tech. Pub. 416. 

A novel comminution device, the roll press, has achieved commercial success [Schoenert, International J. Mineral Processing, 22, 401-412 (1988)]. It is used for fine crushing, replacing the function of a coarse-baU mill or of tertiary crushers. Unlike ordinary roll crushers which crush individual particles, the roll press is choke fed and acts on a thick stream or ribbon of feed. Particles are crushed mostly against other particles, so wear is veiy low. Energy efficiency is also greater than in ball mills. 

Experimental evidence presented in a classic paper bv Coghill and De Vaney ("Ball Mill Grinding, U.S. Bur. Mines Tecti. Publ. 581, 1937) indicated that the efficiency of battered reject balls was about 11 percent less than that of new spherical balls. These and other results have been graphically presented (Rose and Sullivan, Ball Rod andTube Mills, Chemical Pubnshing Co., NY, 1958). 

Modified ball mill configuration, particle size distribution control, improved grinding media and linings, high-pressure roller press for clinker pre-grinding, high-efficiency classifiers, roller mills... 

Titanium nitride-based nanoparticles are also efficient dopants for NaAlH4 in hydrogen storage applications [12, 13]. The black solid TiN powder can be dispersed into the hydride via ball milling. Addition of titanium nitride-based na-... 

The apparent efficiency of the size reduction operation depends on the type of equipment used. Thus, for instance, a ball mill is rather less efficient than a drop weight type of crusher because of the ineffective collisions that take place in the ball mill. 

The ball mill is used for the grinding of a wide range of materials, including coal, pigments, and felspar for pottery, and it copes with feed up to about 50 mm in size. The efficiency of grinding increases with the hold-up in the mill, until the voids between the balls are filled. Further increase in the quantity then lowers the efficiency. 

Much more efficient method of the synthesis of metal hydrides is a one-step method of reactive ball milling of elemental metal directly under hydrogen gas. The method of reactive mechanical alloying/milling of either elemental metals or preaUoyed... 

Fig. 2.38 The effect of ball-to-powder weight ratio on the efficiency of milling under two impact modes (a) IMP710 and (b) IMP58 in the magneto-mill Uni-Ball-Mill 5 [63]...

Quantitative stoichiometric gas-solid or solid-solid (these at 0 °C) acylations of amines with acid chlorides are varied (Scheme 32). However, for a clean reaction the liberated hydrochloric acid has to be neutralized by an additional gaseous or solid base that may also be a second mole of the amine. The reactions are performed in an evacuated flask or in a ball-mill, respectively. There are only minimal losses of the amides or sulfonamides upon removal of the stoichiometric coproduct with water [91]. The solid-solid reactions can be turned into sustainable 100% yield processes with optimal atom efficiency by milling stoichiometric 1 1 1 mixtures of acid chloride, aniline derivative, and K2CO3... 

The pellet (pressed-disk) technique depends on the fact that dry, powdered potassium bromide (or other alkali metal halides) can be compacted under pressure in vacuo to form transparent disks. The sample (0.5-1.0 mg) is intimately mixed with approximately 100 mg of dry, powdered KBr. Mixing can be effected by thorough grinding in a smooth agate mortar or, more efficiently, with a small vibrating ball mill, or by lyophili-... 

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