why marble is not used for cement than limestone?
what are the physiscal,chemical or other properties which selects limestone for cement than marble
what is the bond index / grindiability of marble than limestone
thanks
dot
Ted Krapkat
Hello Dot,
Although marble is simply limestone which has been metamorphosed geologically by heat and pressure, both rocks are chemically and mineralogically the same (Calcite or CaCO3).
However, because of its aesthetic appeal, marble is generally more valuable as a building and construction material in its own right. Also, marble occurs far less commonly in nature than limestone, so large enough deposits for cement manufacture are less likely to be available. But, apart from such economical considerations, there is no other reason why marble cannot be used to make cement.
In fact, many 'limestone' deposits used for cement manufacture are really low-grade marble. This is especially evident if the deposit contains significant volcanic intrusions or other signs of volcanic activity. Also, some cement plants use waste from marble mines as a secondary raw material. This waste may consist of smaller unusable pieces from marble block mining, or off-cuts and dust from marble slab processing.
To answer your last question, the hardness and grindability of both limestone and marble vary widely, depending on their geological origin and history, so marble can be sometimes harder and more difficult to grind than limestone and sometimes the opposite is true.
Ted.
Silastman
Dear Dot !
Our region has a lot of marble deposits. Marble has many varieties. More valuable varieties of marble with beautiful color and high hardness. They are used for the manufacture of decorative products.
http://freemarket.kiev.ua/images_message/663/125957/425868/346181.jpg
But there is a field in which marble has low strength and contains some impurities, while the total contents of CaCO3 is 99.5%. The marble is very soft and easily crushed. But its use for the manufacture of cement to businessmen not profitable, because simply crushing the marble, they have a good product that is bought at the market producers of dry construction mixtures and fiberglass. The price for this product is close to the price of cement.
While I on the basis of such marble received normal Portland cement. Moreover, as the clayey components I used clay, they remove the overburden works the same career. If you have a number of deposit of marble, I don't see any problems that would be used for the manufacture of cement.