subject: How To Make Portland Cement More Efficient [print this page] Portland cement (often referred to as OPC, from Ordinary Portland Cement) is the most common type of cement in general use around the world because it is a basic ingredient of concrete, mortar, stucco and most non-specialty grout. It is a fine powder produced by grinding Portland cement clinker (more than 90%), a limited amount of calcium sulfate (which controls the set time) and up to 5% minor constituents as allowed by various standards such as the European Standard EN197-1.
The Portland cement productive technology is representative in the cement production, it use limestone and clay as raw materials, after crushing, dosing and levigating the raw material was fed to cement rotary kiln , calcined into clinker, then levigate into cement by add moderate gypsum( sometimes add some mix material or admixture) .
ASTM C 150 defines portland cement as "hydraulic cement (cement that not only hardens by reacting with water but also forms a water-resistant product) produced by pulverizing clinkers consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an inter ground addition." Clinkers are nodules (diameters, 0.2-1.0 inch [525 mm]) of a sintered material that is produced when a raw mixture of predetermined composition is heated to high temperature. The low cost and widespread availability of the limestone, shales, and other naturally occurring materials make portland cement one of the lowest-cost materials widely used over the last century throughout the world. Concrete becomes one of the most versatile construction materials available in the world.
The Portland cement productive technology is representative in the cement production, it use limestone and clay as raw materials, after crushing, dosing and levigating the raw material was fed to cement rotary kiln , calcined into clinker, then levigate into cement by add moderate gypsum( sometimes add some mix material or admixture) .
For the preparation methods of raw material are different, cement production can be dry (include semi-dry) process and wet (include semi-wet) process. Portland cement dry process. Drying all materials at the same time then grinding the material or first drying the grinded raw material powder then feed to the dry kiln and calcine into clinker. However, there is another way, add some water into the raw material powder to make the raw material ball, and then feed to kiln to calcined to clinker, this is called semi-wet process, also belongs to the dry process.
Wet process, which is generally conducted by filling water into the raw material, grinding the wet raw material into raw slurry, and then feeding it into kiln to burn into clinker. Or dehydrate the wet processed prepared raw slurry into raw lump and then feed it into kiln to burn into clinker, which is semi-wet process, still remaining kind methods of wet process.Portland cement clinker is made by heating, in a kiln, a homogeneous mixture of raw materials to a sintering temperature, which is about 1450 C for modern cements. The aluminium oxide and iron oxide are present as a flux and contribute little to the strength.
For improving the efficiency of production line, hardware facility is the key point. Cement mill, cement rotary kiln and other auxiliary equipments must be reliable in quality. Cement production line shall be installed according to the actual landform with the site guidance from the experts. The requirement to raw material for cement mill is quite high, so that it is quite wrong to grind the raw material with the same mill, for which would reduce the service life of mill.
