Bags of crushed limestone has an important position in the market and is used in many industries. This article mainly introduces the use of bags of crushed limestone and its production process, as well as its main role in cement.
What are the uses of bags of crushed limestone?
Application in agriculture: Limestone can be used in pesticides, slaked lime can change the acidity and alkalinity of the soil, improve the internal composition of the soil, and supplement the calcium in the soil. At the same time, lime mortar can be used to paint the trunk, which can protect the tree.
Construction of houses and decoration: Limestone is the main raw material for making cement, and it is also used for building the exterior walls and floors of houses.
Manufacture of glass: The materials for making glass are limestone, quartz sand and soda ash, which can be obtained by melting these materials at high temperatures.
Iron and steel smelting: In industrial production, limestone is also a solvent for iron smelting. Quicklime can be used as a slagging material to filter out harmful substances such as sulfur and phosphorus.
Making table salt: Limestone can be made into table salt after chemical processing.
Hard water softener: Slaked lime can temporarily remove the hardness of water, so it is used as a hard water softener in the industry.
How is bags of crushed limestone produced?
The production of bags of crushed limestone is mainly divided into 4 steps:
The first step of crushing: the limestone is evenly fed into the crusher by the vibrating feeder, after multiple crushing and shaping, after being screened by the vibrating screen, the bulk materials with different particle sizes pass through the conveyor belt and are crushed again. The finished products are sent to the finished product area by the belt conveyor.
The second step of calcination: the crushed limestone is heated to partially decompose the limestone, and finally the limestone is put into the cooler, and the material is cooled to below 60 degrees before being discharged from the cooler.
The third step is grinding: after crushing and calcining, the material should be ground, and the material is ground by a grinder, which can meet the requirements of bagged limestone and daily grinding requirements.
The fourth step is delivery of finished products: the finished limestone is transported to the finished limestone silo after being transported, and finally packed into bags of crushed limestone.
What is the role of bags of crushed limestone in concrete?
Limestone, whose main chemical component is calcium carbonate, is generally considered an inert material that acts as a filler in concrete. In order to make limestone powder better used in concrete, many studies have shown that limestone powder is not only used as an inert filler in concrete, but a series of reactions will also occur in bags of crushed limestone in concrete. The hydration process plays a certain role.
At the same time, bags of crushed limestone can also be used as a nucleation collective of calcium silicate hydrate, lowering the nucleation barrier and accelerating cement hydration. At present, the more recognized mechanism of bags of crushed limestone on the performance of concrete is mainly the following four aspects.
The particle gradation and particle size distribution of materials are often neglected in the process of concrete research, especially the particle size distribution of powder materials. Due to the unreasonable particle size distribution and poor gradation of concrete, the internal structure of concrete has large pores.
The specific surface area of the bags of crushed limestone powder is larger than that of cement, and the particle size is smaller than that of cement. The bags of crushed limestone powder is filled in the gap between the cement slurry matrix and the interface transition zone, making the cement structure and interface structure more compact, reducing the The porosity and pore diameter can improve the pore structure, thereby increasing the strength and interface strength of cement.
The bags of crushed limestone powder distributed between the cement particles has a smooth surface and can play a “ball” effect similar to fly ash, which can dilute the cement particles to make them more dispersed, thereby increasing the distance between particles and increasing the fluidity of concrete. At the same time, the bags of crushed limestone powder with a smooth surface is dispersed among the cement particles, which can replace the water filled between the particles, increase the interval water layer between the particles, and open the “flocculation structure” formed during the concrete hydration process.
When the amount of crushed limestone powder in the bag is appropriate, the calcium carbonate in the limestone powder can absorb the calcium ions generated during the cement hydration process, making calcium hydroxide nucleate preferentially, avoiding the local growth of calcium hydroxide into large crystals, and small bags Crushed limestone powder acts as the nucleation matrix of CSH, which can reduce the nucleation barrier and accelerate the hydration reaction rate, thereby improving the distribution of cement hydration products.
Chemical activity effect
The bags of crushed limestone powder is mainly calcium carbonate. In cement-based materials, its chemical activity is low but not completely inert, and it will continue to react with the hydration reaction. This hydration product overlaps with other hydration products, increasing The compactness of concrete, thereby improving the strength and durability of concrete.
How to choose bags of crushed limestone?
- When buying bags of crushed limestone, you should carefully look at the surface of the bags of crushed limestone. If there are many magazines on the surface, it is best not to buy it. Because if there are magazines, the content of limestone will be reduced, which will affect the use.
- When choosing quicklime, you can take some and put it in water to see if it dissolves in water. If it is not easy to dissolve in water, it is not a good material.
- In addition to looking at the meltability, it also depends on the degree of coagulation. If it is difficult to coagulate, it will not work.
- When purchasing crushed limestone in bags, be sure to choose ones that are easy to store.
- It is also necessary to choose environmentally safe bags of crushed limestone to reduce environmental pollution.
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