United States Statistical Data
According to the United States Geological Survey, 1.72 billion tonnes of crushed stone worth $13.8 billion was sold or used in 2006, of which 1.44 billion tonnes was used as construction aggregate, 74.9 million tonnes used for cement manufacture, and 18.1 million tonnes used to make lime. Crushed marble sold or used totaled 11.8 million tonnes, the majority of which was ground very fine and used as calcium carbonate.
In 2006, 9.40 million tonnes of crushed stone (almost all limestone or dolomite) was used for soil treatment, primarily to reduce soil acidity. Soils tend to become acidic from heavy use of nitrogen-containing fertilizers, unless a soil conditioner is used. Using aglime or agricultural lime, a finely-ground limestone or dolomite, to change the soil from acidic to nearly neutral particularly benefits crops by maximizing availability of plant nutrients, and also by reducing aluminum or manganese toxicity, promoting soil microbe activity, and improving the soil structure.
In 2006, 5.29 million tonnes of crushed stone (mostly limestone or dolomite) was used as a flux in blast furnaces and in certain steel furnaces to react with gangue minerals (i.e. silica and silicate impurities) to produce liquid slag that floats and can be poured off from the much denser molten metal (i.e., iron). The slag cools to become a stone-like material that is commonly crushed and recycled as construction aggregate.
In addition, 4.53 million tonnes of crushed stone was used for fillers and extenders (including asphalt fillers or extenders), 2.71 million tonnes for sulfur oxide removal-mine dusting-acid water treatment, and 1.45 million tonnes sold or used for poultry grit or mineral food.
Crushed stone is recycled primarily as construction aggregate or concrete.
Read more about this topic: Crushed Stone
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