Limestone is quarried primarily from open pits. The most economical method of recovering the limestone has been through blasting, followed by mechanical crushing and screening.
Particulate emissions arise from limestone crushing and screening operations. Based on the type of technologies employed for limestone mining and processing, it is assumed that the release of other air emissions or water effluents is negligible.
It is assumed that negligible solid wastes are produced from limestone mining and processing. Any overburden or tailings produced from limestone mining and processing are returned to the mine site.
Limestone Production Line
Lime is never found in a natural state, but is manufactured by calcining (burning) high purity calcitic or dolomitic limestone at high temperatures. The calcination process drives off carbon dioxide, forming calcium oxide (quicklime). The subsequent addition of water creates calcium hydroxide (hydrated or slaked lime).
Lime is a class of various chemical and physical forms of quicklime and hydrated lime. The majority of lime produced in the United States is quicklime. The data in this module represent the calcining of limestone to produce calcium oxide (quicklime); the subsequent production of calcium hydroxide is not included in this module.
Solid wastes generated during the production of lime include impurities removed from the limestone, tailings collected in the lime production process, and lime kiln dust collected from particulate control devices on the lime kilns. Based on lengthy discussions with a confidential industry representative, it was assumed that all collected lime dust and tailings from lime production are either sold for various useful purposes, injected back into mines, replaced in quaries, or land applied on site. Packaging and other industrial wastes from lime production are disposed in a municipal landfill.
