What is the chemical composition of cement?

The quality of cement mainly determines the quality of clinker. High-quality clinker should have suitable mineral composition and petrographic structure. Therefore, controlling the chemical composition of clinker is one of the central links in cement production. 1. Chemical composition of clinker The main chemical composition of Portland cement clinker is calcium oxide, generally ranging from 62-67; silicon dioxide, generally The range is 20-24, the general range of aluminum trioxide is 4-7, the general range of iron trioxide is 2.5-6. These four oxides usually account for more than 95% of the clinker, and also contain less than 5% of a few oxides, such as magnesium oxide, sulfur anhydride, titanium oxide, phosphorus oxide and alkali. These four oxides constitute the main chemical components of cement clinker. In the production of cement clinker, they focus on proportioning production according to a certain content and a certain proportion. Improper proportioning will directly affect the quality of clinker and thus the quality of cement. For example, if the calcium oxide content in the clinker is too high, the calcium oxide cannot fully combine with the silicic acid oxides, and some of the calcium oxide exists in a free state in the clinker, forming a "dead burnt state". This "dead burnt state" of calcium oxide , its hydration is very slow and often occurs in the cement stone after the cement setting process, causing the cement stone to expand, deform, and crack. Such as alumina and iron oxide, they are the main oxides that produce liquid phase during the clinker firing process. If their content is too high, too much liquid phase will be produced, which will easily form large pieces and affect the operation; if If the content is too low, too little liquid phase will be produced, making firing difficult and the clinker easy to "powder". Therefore, heavy laboratory personnel in clinker production must conduct certification analysis and calculations on raw materials to make scientific and reasonable batching plans. Know about clinker production.