Monday, 16 March 2015

Dolomite

Dolomite

Dolomite is a sedimentary rock composed primarily of calcium magnesium carbonate. The word dolomite is also referred to dolomite mineral so sometimes being confused between rock and mineral. Limestone is composed of calcium carbonate and dolomite is composed of calcium magnesium carbonate so it is thought to be originated by the post depositional alteration of limestone via magnesium rich ground water. Dolomite consist all the properties of limestone, have same hardness, reacts with hydrochloric acid and bears the same colour (white to grey or white to light brown).

Dolomitization

As limestone and dolomite shares the same depositional environment as shallow marine, warm water where organism can accumulate which in turn when deposits form carbonate. So in formation of dolomite it is thought to be the alteration of carbonate by magnesium rich water, Magnesium in the water converts calcite into dolomite, This alteration is the chemical change in the limestone which is called dolomitization. This can turn limestone into complete dolomite or can be partial alteration of the rock and is dolomitic limestone.

Metamorphism of Dolomite

When dolomite is subjected to heat and pressure it behaves the same way as limestone. The heat recrystallizes the dolomite crystals which grows into larger crystal form. 

Uses

Dolomite and limestone have similar uses as used in the construction purposes after being crushed into pebbles and cobbles size. These can also be used into dimension stone after cutting into regular size. Dolomite is the preference in the construction industry than that of the limestone because of its greater hardness and less chemical reactivity to acids which makes it perfect for construction uses.
Dolomitization is a process where limestone is converted, it provides opportunity for a reservoir in oil and gas industry because of the reduction in size of limestone which leaves pore spaces that are often filled by oil and gas. These are also host rock for lead, zinc and copper deposits.
Other uses of dolomite are in the chemical industry used to extract magnesia where it is served as the source rock. Steel industry use it in processing iron ore and is also used in the agriculture industry as a feed additive for live stock aiding in the egg shells which are made of calcium. It is also used in the production of glass and ceramics.

0 comments:

Post a Comment