What is Lime?
Lime is a calcium-containing mineral. It is primarily composed of calcium oxides, carbonates and hydroxides. Lime is a very important mineral that is used in a wide variety of industries. It is a major component of concrete and mortar. It is used in livestock feed, in treating wastewater, and in refining sugar. It is used in the manufacturing of plastics, paper and glass. It might be easier to list the industries that it is NOT used in than to list all of the industries that use lime.
Where Does Lime Come From?
Lime is mined from deposits of limestone or chalk, which are composed primarily of calcium carbonates. After the materials are mined, they are crushed and chemically converted. Burning or heating the crushed rock converts the limestone into a highly caustic chemical referred to as quicklime, or calcium oxide. Quicklime can be “quenched” by reacting it with water to form slaked lime (calcium hydroxide), which is not caustic. Confusingly, both forms are often just called lime. Quicklime is a dry powder. Slaked lime can exist as wet slurry or as a dry powder. Slaked lime is mixed with sand and water to form mortar. The calcium hydroxide in the slaked lime reacts with carbon dioxide in the air to convert back into solid limestone, namely calcium carbonate, completing what is called the “lime cycle.”
How is Lime Transported?
Lime transportation from its origin to one of its many industrial uses can be tricky. The fine powdered quicklime is extremely caustic and can burn skin, eyes and lungs; it is also highly reactive with water, and has to be kept as dry as possible. Dehydrated slaked lime is perhaps the easiest form of lime to transport – it is also a fine powder, but it isn’t caustic and it isn’t highly reactive with water. Most uses of slaked lime require that it be converted to slurry by adding water, so it’s also possible to transport slurries of slaked lime as long as they are constantly agitated.
Fine powders, particularly caustic ones, have to be transported sealed inside airtight plastic containers, or for bulk transport, poured into specially designed trailers or railway cars. Slurries, being liquid and requiring agitation, need to be transported in trucks designed to carry liquid cement. Due to their water content slurries are heavier and occupy a larger volume than dry powders, making transport more expensive. When powders arrive at their destination, they are pumped out of the special dry bulk trailers into silos. When slurries arrive at their destination, they are pumped into a special slurry storage tank. Clearly, safe and efficient transport of lime in its many different forms requires specialized equipment and experienced operators. That’s where CCC Transportation can help.