Ground mica

Barwick Standard Distribution Corn. Dry Ground Mica Typical Screen Analysis  

These materials are ground flakes, silver-gray in color. Their composition is Potassium Aluminum Silicate having the following typical chemical coiqposition and analysis  

Iron Oxide (Fe203), % Trace to 3.0 Phosphorous (P), % Trace Loss on Ignition, % Hcucimum 5.0 Moisture, % Maximum 0.5 

Grade Note Coarse, High Aspect Ratio (HAR) 

Typical Sieve Analysis, % Passing-325 mesh 64% Grade Note HAR 

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The coarse mica concentrate is either respiraled to produce a product with a grade suitable for use by wet grinding mica producers, or floated to further upgrade it for specialty high grade dry ground mica products. 

Exact si2ing of mica products coupled with surface treatment procedures have led to a greater use for wet ground mica in plastic compositions, particularly automobile bodies. These quahty products demand a high dollar value. 

Tables 4 and 5 show properties of ground mica products. For all forms of ground mica the index of refraction is 1.58 wt %, Mohs hardness is 2.5, oil absorption (Brit. Stand. 3483) is 60.75%, water solubihty (Brit. Stand. 1765) is <0.3%, the phericity factor is 0.01, and the softening point in °C is 1538. For Microni2ed and wet ground micas the brightness (green filter), pH, and apparent density in kg/m are 75, 5.2, and 160—224, respectively for dry ground mica, 66—75, 6.2, and 192—561, respectively (1).

Table 4. Particle Size Distribution of Ground Mica Products ...

There are several conventional tests required by consumers of ground mica. 

Wet Ground Mica. Wet ground mica is used because of its unique properties, ie, luster, sHp and sheen, and high aspect ratio (1,1 )-... 

Table 8. Ground Mica Sold or Used in the United States ...

M. L. Rajgarhia, Ground Mica, Mica Manufacturing Co., Private Ltd., Calcutta, India, 1987, p. 30 British Standards, British Standards Institute, London. 

Dry ground mica concentrate is processed into usable products hy several dillerent grinding methods. Relatively coarse particle sizes (1.651-0.147 mm (10-100 mesh)) are used in oil-well drilling muds. 

There arc several conventional tests required hy consumers of ground mica. They include screening and Ihe determination of bulk density, true specific gravity, chemical analysis, moisture, free silica, refraction index, oil absorption, brightness, grit content, and aspect ratio. 

MW 0/1mud Mica. Wei ground mica is used because of its unique properties, i.e.. luster, slip and sheen, and high aspect ratio. It is used in wallpaper and coated paper, nacreous pigments, as a coating for rubber, in ouidoor house paint, and in aluminum paints. Mica is used in all types of scalers for porous surfaces, such as vvallboard masonry, and concrete blocks, to reduce penetration and improve holdout and as a filler in plasties to improve its electrical and thermal resistance and its insulating qualities. See also Sealants. 

A BET plot of all the data at 77° is linear over a wide range, and least-squares analysis of all the experimental values in the monolayer region (0.025 < p/p0 < 0.20) yields values of vm = 0.336 cc. per gram and c = 131. While the c value is very close to that previously observed for krypton adsorption on this mica (5), the surface area is appreciably smaller. This decrease in vm has occurred progressively with time for all our ground mica samples, and at present we have no... 

This mode of grading is used on feathers- It is believed by the writer to be used in the dry treatment of mica. The only plant of this kind of any importance is said to use it but details of the means employed cannot be obtained. Ground mica is used in the manufacture of wall papers, lubricants, fancy paints, molded blocks for electrical insulation. About eight sizes of ground mica are made ranging from 10 mesh to bran mica. 

Mica 325, 325FF, 325MF, 325D, AMC, 160 D - dry ground mica for rubber applications. 

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