Published December 2014
Lime, or calcium oxide (CaO), is derived through the decarbonation of limestone. The primary product of limestone decarbonation is called quicklime; it can be hydrated to form hydrated lime or calcium hydroxide (Ca[OH]2). Limestone, a sedimentary rock composed mainly of calcium carbonate (CaCO3), is the precursor in the manufacture of lime and precipitated calcium carbonate.
Production of lime increased strongly during 2008–2014, spurred by recovery following the economic downturn, as demand for steel and construction uses grew. China continues to lead production and consumption of lime, at about 70% of world totals. In developed regions, such as North America, Western Europe, and Japan, production of lime is a mature industry characterized by consolidation among regional producers, each servicing its regional markets. There is relatively very little trade worldwide, primarily because lime is readily available in all parts of the world and transportation costs can account for a significant portion of the product value.
The following pie chart shows world consumption of lime:
The major use for lime is in metallurgy, including steel production, accounting for nearly half of total lime consumption in 2014. Consumption for construction uses, primarily for soil stabilization, accounts for more than 20%. Environmental uses, including flue gas desulfurization, water treatment and waste treatment, are expected to be some of the fastest-growing applications through the forecast period. The majority of the remaining consumption is for various chemical and industrial uses, such as production of precipitated calcium carbonate (PCC), aluminum oxide, calcium carbide and soda ash. World consumption of lime is expected to grow at an average annual rate of 4–5% in 2014–2019, led by demand growth in China; lime consumption in developed regions is expected to increase at a modest 1% per year.
Quicklime is primarily used in metallurgy (steel) and flue gas desulfurization, while hydrated lime (also known as slaked lime) is used in construction (soil stabilization) and water treatment. Limestone is an important raw material with a wide range of applications, but its primary use is in the construction industry, where it is the principal source of crushed rock aggregate. It is also an essential raw material for cement manufacture, and a source of building stone.