Grinding Aid Research Articles

The influence of additives on the grinding of γ-alumina for the production of high-alumina ceramics

Reactivity of alumina can be increased by decreasing its ultimate crystal size. Dry ball milling, with some organic grinding aids, minimised mill packing and promoted fine grinding of γ-alumina. The effects of oleic acid, stearic acid, aeropromotor 765 and naphthenic acid on the size distribution and specific surface of the ground product were investigated. Aeropromotor 765 and naphthenic acid were both found to be effective in grinding, but their combined effect is more pronounced after firing. Ground products obtained by dry ball milling had satisfactory bulk density and cold crushing strength. The effect of these reagents on the shrinkage of alumina fired bodies had been shown. Distinct optima corresponding to the relative effect of these reagents on the firing characteristics of alumina bodies were correlated with their effectiveness in grinding. At the optimum conditions, a ground product pressed at 720 kg/cm 2 fired at 1550°C for 30 minutes, had a bulk density of 1.94 g/cm 3, a cold crushing strength of 296.6 kg/cm 2 and 8.95% shrinkage.

X-Ray Fluorescence Analysis of a Manganese Ore

AbstractTo replace time-consuming chemical analysis, a procedure was developed for applying X-ray fluorescence to the analysis of a manganese ore. This X-ray fluorescence method is rapid; the total time for both sample preparation and analysis is ½ hr. The method is also simple enough for routine laboratory use. The components determined, the concentration ranges, and the agreement between chemical and X-ray analysis in terms of standard deviation are:The agreements between chemical and X-ray analysis noted for manganese and iron are obtained by correcting for CaO concentration when determining the manganese and for manganese and SiO2 concentrations when determining the iron. The corrections employ empirical equations developed by a multiple regression technique.Sample preparation is reduced to a minimum because it consists of only two steps, pulverization of the manganese ore followed by briquet ring. Four minutes of grinding with Boraxo as the grinding aid gives sufficient uniformity to minimize the effect of particle size variation. The ground mix of manganese ore and Boraxo is pressed into 1.25-in. briquettes for analysis.

Sterotex—A Grinding Aid

Powdered samples for x-ray analysis are often ground in mills by using a rotating ring and puck inside a grinding cylinder. Such commercial grinders are the Disc Mill (Angstrom, Inc.), Bleuler Mill (Applied Research Laboratories, Inc.), and Shatter-box (Spex Industries, Inc.). A grinding aid is frequently added along with the sample to increase the grinding efficiency, to minimize contamination caused by abrasion with the grinding media, and to eliminate sample’s sticking to the grinding surfaces and thus aid in sample transfer. Grinding aids frequently employed are soap powders, sodium alkylsulfonate, and Boraxo. These products contain sodium; this precludes their use when sodium is to be determined. Sterotex powder,1 a vegetable-fat product that is free of the elements determined by x-ray, has been tested and used as a grinding aid. Sterotex, a fine powder about 95% −200 mesh, easily and uniformly disperses with the sample. When required, it can be premixed with the sample to minimize spot-impacting of the sample on the grinding surfaces. To eliminate this problem with, for example, Boraxo, the as-received product should be ball-milled to about −50 mesh. Sterotex also imparts some binding action when briquets are prepared from the pulverized sample.

Colloidal carbon as a grinding aid in Portland Cement Manufacture

Colloidal carbon as a grinding aid in Portland Cement Manufacture

Colloidal Carbon as a Grinding Aid In Portland Cement Manufacture

Colloidal Carbon as a Grinding Aid In Portland Cement Manufacture