Limestone is a sedimentary rock composed primarily of calcium carbonate (CaCO3) in the form of the mineral calcite. It most commonly forms in clear, warm, shallow marine waters. It is usually an organic sedimentary rock that forms from the accumulation of shell, coral, algal and fecal debris. It can also be a chemical sedimentary rock formed by the precipitation of calcium carbonate from lake or ocean water. Most limestones form in shallow, calm, warm marine waters. That type of environment is where organisms capable of forming calcium carbonate shells and skeletons can easily extract the needed ingredients from ocean water. When these animals die their shell and skeletal debris accumulate as a sediment that might be lithified into limestone. Their waste products can also contribute to the sediment mass. Limestones formed from this type of sediment are biological sedimentary rocks. Their biological origin is often revealed in the rock by the presence of fossils. Some limestones can form by direct precipitation of calcium carbonate from marine or fresh water. Limestones formed this way are chemical sedimentary rocks. They are thought to be less abundant than biological limestones.
Physical Property
Physically, Limestone are Quite impervious, Hard, Compact, fine to very fine grained calcareous rocks of sedimentary nature
Chemical Property
Chemically, limestone is siliceous calcium carbonate rocks.
Dimension Stone
Limestone is often cut into blocks and slabs of specific dimensions for use in construction and in architecture. It is used for facing stone, floor tiles, stair treads, window sills and many other purposes.
Roofing Granules
Crushed to a fine particle size, crushed limestone is used as a weather and heat-resistant coating on asphalt impregnated shingles and roofing. It is also used as a top coat on built-up roofs.
Flux Stone
Crushed limestone is used in smelting and other metal refining processes. In the heat of smelting, limestone combines with impurities and can be removed from the process as a slag.
Portland Cement
Limestone is heated in a kiln with shale, sand and other materials and ground to a powder that will harden after being mixed with water.
AgLime
Calcium carbonate is one of the most cost-effective acid neutralizing agents. When crushed to sand-size or smaller particles limestone becomes an effective material for treating acidic soils. It is widely used on farms throughout the world.
Lime
If calcium carbonate (CaC03 is heated to high temperature in a kiln the products will be a release of carbon dioxide gas (CO2) and calcium oxide (CaO). The calcium oxide is a powerful acid neutralization agent. It is widely used as a soil treatment agent (faster acting than aglime) in agriculture and as an acid neutralization agent by the chemical industry.
Animal Feed Filler
Chickens need calcium carbonate to produce strong egg shells so calcium carbonate is often offered to them as a dietary supplement in the form of "chicken grits". It is also added to the feed of some dairy cattle who must replace large amounts of calcium lost when the animal is milked.
Mine Safety Dust
Also known as "rock dust". Pulverized limestone is a white powder that can be sprayed onto exposed coal surfaces in an underground mine. This coating improves illumination and reduces the amount of coal dust that activity stirs up and releases into the air. This improves the air for breathing and it also reduces the explosion hazard produced by suspended particles of flammable coal dust in the air.
Limestone has many other uses. Powdered limestone is used as a filler in paper, paint, rubber and plastics. Crushed limestone is used as a filter stone in on-site sewage disposal systems. Powdered limestone is also used as a sorbent (a substance that absorbs pollutants) at many coal-burning facilities.
