There are many classification methods of cement, commonly it can classify according to 1.Usage.It can be divided into oil well cement, dam cement, jet cement, maritime works cement. 2. The main chemical composition in the cement. It can be divided into Portland cement, sulphate aluminum cement, aluminium cement (high aluminium cement) and phosphate cement etc. Although the varieties of cement is various, but more than 95% of them is belong to silicate cement class. They are just product by changing chemical composition according to the requirement of the project, or joining some regulation performance substance when be used. The production technology of Portland cement is representative in the cement production process. It uses limestone and clay as the main raw materials. The raw materials treated through breaking, distribution, fine grinding and burning in the cement kiln and become the clinker. The clinker added proper quantity gypsum (sometimes added mixed material or additives) grinded finely and become the Portland cement.