What is the normal activity level of limestone after calcination
Limestone, as an important mineral resource, can be converted into lime after calcination, and the activity of lime is an important indicator to measure its quality. So, what is the normal activity level of limestone after calcination?
The activity of lime is usually determined by acid-base titration, which involves reacting a certain amount of lime with hydrochloric acid and determining the activity of lime based on the volume of hydrochloric acid consumed during the reaction. Generally speaking, lime with an activity level of over 300mL (4N HCl) is called active lime, which has a wide range of applications in industrial fields such as steelmaking.
During the calcination process of lime, various factors can affect its activity. Firstly, the raw material characteristics of limestone include purity, particle size, and mineral composition. Limestone with high purity and small particle size is more prone to decomposition during calcination, and the resulting lime has relatively high activity. In addition, certain minerals in limestone, such as silica, can also affect the activity of calcined products. When the silica content is high, the activity of lime will significantly decrease after high-temperature rapid calcination.
The calcination process is also a key factor affecting the activity of lime. The selection of calcination temperature is crucial, as high activity can generally be achieved between 850 ℃ and 1000 ℃. However, different limestone raw materials may require different calcination temperatures, so adjustments need to be made according to the characteristics of the raw materials in practical operations. In addition, calcination time can also have an impact on the activity level. Prolonged calcination time may lead to overburning of lime, thereby reducing its activity level.
In addition to the above factors, atmospheric conditions also have a significant impact on the activity of lime. Lime calcined in a reducing atmosphere has higher activity because the reducing atmosphere is conducive to the decomposition of limestone and the generation of calcium oxide.
What is the normal activity level of limestone after calcination? In fact, this value is not fixed, but is influenced by various factors. Generally speaking, if appropriate raw materials and process conditions are used, the activity of the obtained lime should be able to reach over 300mL (4N HCl), or even higher. In certain specific applications, such as converter steelmaking, higher requirements are placed on the activity of lime, which may require a concentration of 370ml/4N-HCI or higher.
The activity of limestone after calcination is influenced by various factors, and the normal range also varies depending on the application scenario. In practical operation, it is necessary to adjust according to the characteristics of raw materials and process conditions to obtain active lime that meets the requirements.
