Grind time

The energy laws of Bond, Kick, and Rittinger relate to grinding from some average feed size to some product size but do not take into account the behavior of different sizes of particles in the mill. Computer simulation, based on population-balance models [Bass, Z. Angew. Math. Phys., 5(4), 283 (1954)], traces the breakage of each size of particle as a function of grinding time. Furthermore, the simu-... 

The question arises whether an internal standard can be relied upon to eliminate physical differences among samples, the Class II deviations of Section 7.8. No clear answer is possible. Variations in intensity ratios with particle size and with length of grinding time have been observed, especially in the analysis of minerals, but these effects seem due primarily to a nonuniform distribution of the internal standard, and not to particle size as such. These two possible causes of nonuniformity are difficult to separate. 

It can be seen from Fig. 8.5 that pyrite still exhibits the cathodic characteristic when sphalerite is used as the opposite electrode at static state. The corrosion potential of the pyrite electrode decreases at the beginning and is finally stabilized at about 140 mV. The pyrite electrode has not exhibited obvious cathode current. When sphalerite is used as the grinding media as seen from Fig. 8.6, the potential of pyrite electrode decreases with the increase of the mechanical pressure exerted on it and the grinding time. Pyrite exhibits cathodic characteristic, but the degree of cathode polarization is less than that in Fe grinding media. Corrosion potential of the pyrite electrode reaches to the lowest value about 145 mV at pressure of 800 g and 8 min. 

Table 10.10 Separation results of the mixtures of two minerals (1 1) among galena, sphalerite and pyrite by h controlled flotation (pH modified by lime, grinding time for 5 min, in Fe medium)...

Bobka (144) studied the adsorption of diphenylguanidine on graphite wear dust. As was shown by Rivin (85), diphenylguanidine adsorption is equivalent to NaHCOj neutralization in the determination of carboxyl groups. With increasing grinding time, surface area and diphenylguanidine adsorption increased parallel to each other. 

In our ease the hydrogen eonsumption of the former deconvolution peak is always indicating a reduction exceeding the mere Co Co. At one hour of grinding time sample BOl shows a 17.5% eonversion to the metal, whieh first increases to 31% after two hours (sample B02) and then deereases regularity to 13.7% after 10 hours of milling (sample BIO). The citrate sample, with the lowest surface area (see Table 1), yields only 2.3% conversion to the metal. Obviously some Co must be aheady formed at this intermediate temperature, well below the seeond peak eorresponding to the complete Co Co reduction of the bulk cobalt. 

Deters (14) vibromilled a blend of cellulose and cellulose triacetate. The acetic acid content of cellulose acetate decreased with grinding time (40 h) while that of the cellulose increased, suggesting the formation of a block or graft copolymer or of an esterification reaction by acetic acid developed by mechanical reaction. Baramboim (/5) dissolved separately in CO polystyrene, poly(methyl methacrylate), and poly(vinyl acetate). After mixing equal volumes of solutions of equivalent polymer concentration, the solvent was evaporated at 50° C under vacuum and the resultant product ball-milled. The examination of the ball-milled products showed the formation of free radicals which copolymerized. 

Surface-active agenta Grinding time 00 Oxygen content (ppm) Bs (T) Magnetic property Br (T) iHc (kA cm ) ... 

Cement clinker Air Organosilicon (0.01-0.05 ) 70 reduction in grinding time... 

Alumina Water Organosilicon 75 reduction in grinding time... 

Fig. 8. Comparison of the cumulative mass distribution P obtained by wet milling of a-alumina (cm = 0.2, pH 5.1) at different grinding times with simulation results.

Comparison of calculated mean particle size m, flatness coefficient K, and skewness coefficient IA,. Terracotta grinding in the mill at Opoczno S.A. Grinding time (min)... 

Fig.33 Relative emission intensity of [(TPA Au1] [AuI(CN)2]> (TPA is l,3,5-triaza-7-phosphaadamantane) with respect to grinding time. The spectra were recorded at 78 K with an identical PMT gain, slit width, and other instrumental setup. No emission is evident before grinding the crystalline sample. From [54]...

The changes of initial electrode capacity as a function of grinding time are presented in Fig. 4. It clearly shows that the specific capacity markedly increased with increasing grinding time up to 72 h and then dropped to nearly nil with 240 h of milling. In particular, the discharge capacity for the electrode fabricated from the composite ground for 72 h was ca 378 mAh/g at the first cycle. Flowever, the electrode capacity of the material milled for... 

FIGURE 13.2 Cumulative mass fraction of ground material as a function of grinding time (Example 13.2). 

This paper will discuss the evaluation of several wet milling systems for providing precisely controlled (percent a.i., particle size, etc.) aqueous base flowables in a wide range of sample sizes. Included will be data on grind parameters (i.e., grind time vs. grind media type and charge) for the Crescent Dental Mills, as well as the. 01,... 

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