(1) Limestone contains effective components to meet the raw mix. The ingredients in the raw material are mainly CaCO3, SiO2, Al2O3, Fe2O3, each occupying a certain proportion, as long as the content of silicon, aluminum and iron in the limestone ore does not exceed the specified value in the raw material ingredients, you can realize the high and low materials proportioning. And most of the impurities in limestone ore are these three substances, as long as the content of the components in the impurities does not exceed the highest requirements of raw material ingredients, it can be used as raw materials, and the insufficient SiO2, Al2O3, Fe2O3 can be completed during the raw mixing.
(2) The downhill limestone should form a relatively composition stable material flow. The production of cement is continuous, and the fluctuation of its composition often brings various changes, making the production unstable. So the optimization of limestone mine materials, is to have a relatively stable source of materials, that is, according to the productivity, to combine shot-term and long-term plan. Make sure not only small fluctuation of main component CaCO3, but also control the fluctuations of other ingredients, so that the fluctuations in the composition of the material are as small as possible, so as to stabilize the production of the plant.
(3) Harmful components must be effectively controlled. The harmful components in cement mines are mainly magnesium, alkali and sulfur. Magnesium oxide is more common in limestone mines, its content varies greatly, because in the clinker calcination, part of magnesium oxide combines with clinker minerals and fused in the liquid phase. Therefore, when the clinker contains a small amount of magnesium oxide, it will reduce the clinker liquid phase generation temperature to increase the number of liquid phase, reduce the viscosity of the liquid phase, which is beneficial to the formation of clinker, and also improve the color. In clinker, the total solid solution of magnesium oxide can reach 2%, and the rest is magnesite which exists in free state. This mineral can be slowed in hydration and expand in volume, which can lead to poor stability, and therefore must be controlled at source. Alkali chloride sulfur, more or less present in limestone mines, is present in one or several forms. During production process, their own physical phase and its physical and chemical properties will change with different temperatures. Volatilization by heat in the high-temperature zone and goes into the back of the smoke chamber, decomposition furnace and pre-heater system by smoke, it will become cohesion on the surface of raw material and forms low-temperature eutectic. These powder particles containing liquid phase which are very easy to bond on the inner wall of the pre-heater. These eutectic material`s content needs to be strictly controlled, especially make sure the magnesium oxide and sulfur content must not be high at the same time. The general requirements are raw material in the alkali content <1.5%, chlorine content <0.02%, sulfur content <1.3%. After comprehensive consideration of the harmful components in the auxiliary materials, the control of harmful components in limestone mines is clear.