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Norlite Corporation 628 S. Saratoga Street Cohoes, NY 12047 Phone (518) 235-0030 Fax (518) 235-0233 E-mail: farchambault@norliteagg.com |
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 Introduction |
Natural Resources
The raw material for Norlite is a thick sequence of shale, approximately 450 million years old, known as the Normanskill Shale. The rock is an exceptionally uniform, dark gray to black, very fine-grained shale with occasional thin, discontinuous beds of mudstone and siltstone. Extensive drilling as well as regional geologic relationships demonstrate the uniformity of the shale and its extreme thickness, estimated to exceed 3,000 feet. The quarry is assured of a long-term supply of uniform quality raw material to maintain the feed for high quality lightweight aggregate.
The Manufacturing Process
Norlite is produced from shale located in a quarry immediately adjacent to the plant. The shale is removed by drilling and blasting and transported by dump vehicles to a closed circuit double roll impact crusher. The primary crushings are conveyed to a double deck screen for sizing to minus 2 inch and plus 1/2 inch material. The sized raw shale is then conveyed to a storage silo where it is discharged by controlled feed into the kiln. The shale is expanded in an 11' by 175' oil fired rotary kiln where temperatures in the burning zone are maintained from 2000 to 2100 Fahrenheit. At this temperature the shale reaches what is known as the point of incipient fusion where the shale is in a semiplastic state. At this point, entrapped gases are formed and expansion results creating individual non-connecting air cells. The expanded shale is discharged from the kiln onto an air quenched grate cooler. The cooled vitreous clinker is conveyed on an 18 inch belt for stockpile storage. The clinker is conveyed to a crusher and finish mill. The crushed and ground material is again moved by covered conveyors to properly sized screens atop totally enclosed storage silos, and there sized to the desired gradations. The aggregate is drawn from the silos by vibrating and belt feeders to a conveyor for truck or rail loading. On isolated jobs or in plants with limited space, Norlite can be shipped as an accurately proportioned customized blend from the calibrated silo feeders. Norlite is available for shipment in bulk by rail or truck and barge, in the following sizes: (Structural) 3/4" and 3/8", (Fines) 3/16" - 0 and (Block Mix) 3/8" - 0.
Thermal Insulation
In an age of energy conservation, the thermal insulation properties of lightweight concrete and concrete masonry units are of growing importance. Because Norlite is a Rotary Kiln expanded shale the manufacturing process creates an insulating material. Within each aggregate there are millions of minute separated air cells which greatly enhance the thermal resistance (R) of the concrete. Norlite concrete has the capability of providing more than double the thermal insulation value of normal weight concrete.
Fire Resistance
All combustible material is burned out in the manufacturing process therefore the fire resistance of Norlite concrete is greater than that of natural aggregate concretes.
Chemical Inertness
Norlite is a chemically inert manufactured lightweight aggregate which causes no staining, popouts, disintegration or adverse reaction to metal or steel in construction.
Abrasion Resistance
Laboratory tests have indicated that rotary kiln expanded shale concrete has superior abrasion resistance to natural aggregate concrete.