History teaches that ...
 

LIME has been one of man's most vital chemicals from the earliest times. In one of the first manufacturing processes ever developed, early cultures learned to make lime by heating limestone (calcium carbonate) to high temperature, and it is still manufactured by this method today. This process, known as calcining, results in quicklime, or calcium oxide. Hydrated lime (calcium hydroxide) is produced by reacting quicklime with water. In addition to high calcium lime, dolomitic quicklime and dolomitic hydrated lime, containing magnesium as well as calcium compounds, are also produced. The uses of lime have increased and evolved over millennia. Lime's earliest uses were in building and agriculture. Indeed, it was used in building the pyramids of ancient Egypt, and in the many construction projects of imperial Rome. With the rapid growth of the chemical process industries at the turn of the twentieth century, progressively large, quantities of lime began to be used in industry as a chemical reagent until, today, more than 90 percent of the total amount of lime is sold or used as a chemical in its oxide and hydroxide form. Hence, lime is now regarded as a basic or industrial chemical, as well as a building and agricultural material. It is extensively used in steel manufacturing, mining, and glass manufacture, and has numerous and growing applications in the environmental sector, including use in air and water pollution control. Lime also plays a major and growing role in soil stabilization for highway and runway construction, as an asphalt additive, and as a precipitant in the paper and sugar industries.
Lime is used - directly or indirectly - in the manufacture of virtually every consumer or industrial product. Chemical and industrial processes require lime for purifying metals (as a flux), neutralization, causticization, coagulation, precipitation, hydrolysis, dehydration, high temperature processes, exothermic reactions, dissolution, gas absorption, and saponification. Lime ranks fifth among industrial chemicals in both tons shipped and tons consumed. Recent annual U.S. commercial lime production was more than 19 million metric ton (more than 21 million short-tons). This tonnage is exclusive of the significant consumption of regenerated lime, mainly at sulfate pulp plants and to a lesser extent at water treatment plant where waste calcium carbonate sludge is dewatered and recalcined in kilns for reuse along with some "make-up" lime.

The term “Lime”...
 

The term "lime" refers primarily to six chemicals produced by the calcination process and hydration, where necessary.

• CaO quicklime
• CaO + MgO dolomitic quicklime
• MgO dead burned dolomite
• Ca(OH)2 hydrated lime
• Ca(OH)2 + MgO type N dolomitic hydrate
• Ca(OH)2 + Mg(OH)2 type S dolomitic hydrate

The last 50 years have seen tremendous growth in lime output despite some significant decreases during poor economic times and some major market shifts.
Changing technology, economics and environmental regulations have played large roles in some lime markets. The steel industry is the best example of where a change in technology, the replacement of open-hearth furnaces with basic oxygen furnaces, resulted in a dramatic change in the quantity and kinds of lime used.

 Lime from A ... to Z

 The different uses
 

35%
 

 Metallurgy 
 

4%
 

 Pulp & Paper 
 

28%
 

 Environmental uses 
 

3%
 

 Sugar refining 
 

13%
 

 Construction & Building material 
 

<1%
 

 Glass products 
 

3%
 

 Chemicals 
 

<1%
 

 Agriculture, Food & Food by-products 
 

7%
 

 Precipitated Calcium Carbonate 
 

1%

 Miscellaneous uses 

Information update 2004 - Data, information and photos courtesy of:
National Lime Association ("Lime Facts" bulletin),
U.S. Geological Survey ("Mineral Commodity Summaries"),
the Ethnographic Museum of Serio Valley (Bergamo, Italy)