Asbestos hardness

Toxic substances are ones which impede or prevent the function of one or more organs within the body, such as the kidneys, liver and heart. A toxic substance is, therefore, a poisonous one. Lead, mercury, pesticides and the gas carbon monoxide are toxic substances. Carcinogenic substances are ones which are known or suspected of promoting abnormal development of body cells to become cancers. Asbestos, hard wood dust, creosote and some mineral oils are carcinogenic. It is very important that the health and safety rules accompanying the substance are strictly followed. 

Selected exposures siUca, asbestos, hard metals, coal, berylliuni, aluminum Hypersensitivity pnenmonitis Selected exposures animal proteins (pigeons, parakeets, budgerigars, chickens, rats), fungi and bacteria (numerous), chemicals (isocyanates, pesticides)... 

Other Bulk Physical Properties. The hardness of asbestos fibers is comparable to that of other crystalline or glassy siHcates. Compared to glass fibers, amphiboles have similar hardness values, while chrysotile shows lower hardness values. 

Soon after World War II the hard thermoplastic floor tile was developed. These tiles use coumarone resins as a binder for the other ingredients, which may contain fibrous fillers such as asbestos, inert fillers such as china clay and softeners such as paraffin wax. 

A Combustion Tube of Hard Glass.—It should be about 13 mm. inside diameter, and the walls not more than i 5 mm. thick. Its length should be such that it projects at least 5 cm. (2 in.) beyond the furnace at either end. After cutting the required length, the ends of the tube are carefully heated in the flame until the sharp edges are just rounded. The tube is filled as follows. Push in a loose asbestos plug about 5 cm. (2 in.) from... 

Drops of molten calcium falling on to hard asbestos cement sheeting caused a violent explosion which perforated the sheet. Interaction with sorbed water seems likely to have occurred. 

Asbestos fibers plus 30-45% special Flashing cement (hard setting) (asbestos)... 

The appatatus consists of a brass cup (See Fig F10), supported by a metal heating plate, XA inch thick and 6 inches in diameter (not shown here). In the center of the plate there is a plane depression l/32 inch in depth, and of just sufficient diameter to fit the cup. There is also a circular opening 2-3/16 inches in diam, cut thru the plate, centering with the center of die above-mentioned depression. The plate is covered with a sheet of hard asbestos board % inch thick, and of die same shape as the metal plate and with a hole cut in the center just to fit the cup. Heat may be supplied from any convenient source. The use of gas burner, electric heater, or alcohol lamp Is permitted, but under no circumstances are... 

As one might expect there is an approximate correlation between the solid state structure and the physical properties of a particular silicate. For instance, cement contains discrete 8104 units and is soft and crumbly asbestos minerals contain double chains of 8104 units and are characteristically fibrous mica contains infinite layers of 8104 units, the weak bonding between the layers is easily broken, and micas show cleavage parallel to the layers and granite contains feldspars that are based on three-dimensional 8104 frameworks and are very hard. 

This cement may be applied on cracks but not on joints because it becomes as hard as stone on standing. A litharge putty may be prepd by mixing 73 ps of litharge, 8 ps of flock asbestos and 19 ps linseed oil. The mixt sets in about 7 days and resists acids up to about 50% strength. The so-called "German putty consists of 70 ps quartz flour, 8.5 ps fluosilicate, 1.5 ps clay in 20 ps of water glass (NaaO 20, SiOa 60 and... 

CHRYSOTILE. A delicately llbrous variety of serpentine which separates easily into silky, flexible fibers of greenish or yellowish color, wrlh formula MgtSUOdGHlj. It crystallizes m the monoclinic system hardness. 2.5 sp gr, 2.55. Its name is derived from [he Greek words meaning gold and fibrous. Most of the common asbestos of commerce is chrysolile. It is mined in Thelford. Province of Quebec, and in the Republic of South Africa. See also Asbestos and Serpentine. 

CROCIDOLITE (Blue Asbestos). The mineral crocidolilc may be considered as u fibrous variety of the monoclinic amphibole. riebeckile. Ii is also known as a massive mineral. Iis hardness is 4 specific gravity, 3.2-3.3 luster, silky to dull color, blue or bluish-green. It is found in Austria, France. Bolivia, the Republic of South Africa (the variety known as tiger s-eye) and in the United States, in Massachusetts and Rhode Island. The name crocidolile is derived from the Greek, meaning to weave, in reference to its fibrous appearance. See also Uat s-Eye. 

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