Calcium carbonate Museum

CaCO3 in our life field

You can find CaCO3 everywhere in your life stage and used for many things. It can be said CaCO3 is just like good supporting role of our contemporary life. Because limestone(CaCO3) is entirely harmless, white, not expensive and produced huge amount, CaCO3 is used every where. Let’s take a look how exist CaCO3 in nature and how used in our life.

CaCO3 in nature

1.Calcium carbonate was formed by inner energy of Earth.

CaCO3 is changed its shape by the diastrophism, heat, pressure, etc.
As mentioned previous chapter there are calcite, aragonite and low crystallinity marble and limestone as calcium carbonate mineral crystals. Calcite has high refractive index, so sliced calcite give a beautiful light same as jewels, but calcite is soft and its hardness is very low, so that calcite is no practical use as a jewel.
the source
1) Gunma Museum of Natural History (http://www.gmnh.pref.gunma.jp/)
2) Virtual Museum of Gems & Gem Crystals (http://www15.plala.or.jp/gemuseum/)

2.Life-form create calcium carbonate.

Almost calcium carbonate on present Earth is created by life-form such as coral, fusulina and sea lilies as a shell.
Let’s show another example. Right picture is a structure of Peal. 93% of pearl’s element is calcium carbonate. The surface is very thin layer of calcium carbonate (aragonite) and protein. These two layer are laminated regularly. One calcium carbonate layer thickness is about 400nm.  It can also be said this is a nanomaterial made by nature. Pearl surface layer thickness is a same size of visible rays wavelength(380~780nm), so it could be occurred the interfere with each other. As the result pearl has a deep fascinating brilliance.

CaCO3 from Mars

In 1993 Martian meteorite(ALH84001) was discovered in South Pole. NASA discovered the material which had shown a sign of existence of lives. That is calcium carbonate which involve magnetite that bacteria create in Earth. The Martian meteorite picture(left side) is taken by electron microscope. It is conceivable that he tube on the picture center is a trace mark of bacteria. The tube(bacteria) length is from 20 to 100 nm. These are also conceivable that this bacteria and CaCO3 was clung in from 3.6 to 4billion years ago on Mars.

CaCO3 for industry

The right figure indicate Japanese annual limestone output and items in 2002. The Japanese limestone output is the next largest after USA. Almost limestone is used for building stuffs.
Let’s take a look how CaCO3 is used with concrete examples.

1.Building materials

We the human beings had been using CaCO3 with the progress of civilization. One of the use is building materials. For examples. The pyramid of Egypt was build 5000 years ago. Big limestone its weight is more than 10 tons are well used for building the pyramid. At the present day, there is no need to say limestone and marble are used for building materials. Today, limestone is also a raw material of concrete(cement).

2.Steel

Steel and CaCO3. It seems there are no relations about two materials but both materials have deep relations. Iron ore is a raw material of steel. Iron ore contains only 60% iron, so it needs to remove other impurities from iron ore. CaCO3 react with theses impurities and easy to remove impurities from iron ore. 0.2tons of CaCO3 is used to make one ton of steel.

3.Other

CaCO3 is used in many fields. For example, plastics and rubber products needs CaCO3 to make it stronger and harder and hard to burn. Paper also need CaCO3 to improve surface complexion and prevent to ink sinking into the paper. Further more CaCO3 is employed for soil amelioration as a fertilizer in farming field. And CaCO3 is used for paint, tile, china, food additives, medicine, tooth paste, feed of domestic animals, pigment etc. so CaCO3 is an indispensable material for things familiar close to our life.
The source:
Japan Lime Association
“The story of limestone”p.40(1987)
  • Calcium carbonate Museum
  • Where CaCO3 came from?
  • CaCO3 Properties
  • CaCO3 in our life field
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  • 日本石灰協会
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