One of the materials you also often encounter in construction or life is limestone. So what is limestone? How are they applied and what types are there? This is not something that anyone can answer. So let's find out with us now.

1. What is limestone?
Before going to learn more about limestone, we need to know what limestone is? Limestone is considered a sedimentary rock. Components of limestone are mainly calcite minerals, ie calcium carbonate, denoted as CaCO3. This type of rock is often mixed with impurities, but very rarely they are in pure form. Some impurities mixed in limestone are clay, sand, mud, bitumen. The color of the limestone is also quite varied, from white to ash to light green, yellow, even dark pink and black.

2. Characteristics of limestone
According to the scientists measured, the limestone has:

Hardness: 3
Volumetric volume: 2,600 ÷ 2,800 kg / m3
Compressive strength: 1700 ÷ 2600 kg / cm2
Water absorption: 0.2 ÷ 0.5%
Limestone types with a high silicon content will have great hardness but are quite brittle and hard. Compared with ordinary limestone, dolomite limestone has better mechanical properties. Limestone types containing a clay content of more than 3% have poor water resistance.

Some places in Vietnam with a lot of limestone are: Tai Meo Mountain, Phong Nha Cave, Ha Long Bay, Karst Plain, Karst Caves, limestone erosion.

You can replace limestone formation through the formation of stalactites in caves.

The chemical formula of limestone occurs in two dimensions:

(1) CaCO3 + CO2 + H2O ↔ Ca (HCO3) 2 (2)

In the forward direction, ie from (1) -> (2) shows the process of limestone erosion. In the opposite direction, ie from (2) -> (1) shows the formation of stalactites in the caves.

3. What is limestone used for?
What is used for limestone is also something that many people are concerned about today. Although limestone is not as solid compared to granite granite, they are more commonly used. The reason is that limestone is easier to exploit and process. People often use limestone as aggregate for concrete or they can also be used to spread the surface of cars and railroads. In some irrigation structures they are also used. In addition, people also use limestone to make panels, paving or other architectural structures. In particular, limestone is used a lot in the production of lime and cement.

4. Classification of limestone
4.1. Classified by mineral composition
If classified according to the mineral composition, limestone has two main types: limestone and dolomite. In addition, there are also some other intermediate rocks such as transition between limestone and dolomite, transition between limestone and clay, transition between limestone and silite, transition between limestone and organic matter.

4.2. Classified according to mineral composition and insoluble composition
If classified according to this method, there will be 22 types of limestone belonging to this group, including: Clay, Limestone and dolomite, Macron - clay, Macron - dolomite clay, Macron - clay - dolomite - lime, Macron - dolomite, macron, dolomite, macron - dolomite, limestone, dolomite, clay lime, clay lime - dolomite, dolomite - clay limestone, limestone, dolomite limestone, limestone - dolomite, dolomite containing lime - clay, dolomite containing clay - lime, dolomite containing clay, dolomite containing lime, dolomite - lime and dolomite.

5. How to heat limestone with a rotary kiln?
You can perform limestone calcining with a rotary kiln according to the following process:

Stage 1: Crushing
Use an impact compressor or an impact machine to crush limestone. Although the crushing mill works slowly, there is a steady pressure when crushing the limestone. The impact machines are impacted with high intensity. People often use a crushing mill to crush large rocks and an impact machine uses a small limestone crushing machine. After the stone is crushed, it will be screened to have the desired size and stored in a reserve.

The crushed limestone is passed through the lifting machine, followed by the super fine powder mill above the hot box machine. There are 2 feeders located above the hot box. Next is through the powder feeding tube to the hot box steadily.

Stage 2: Burning limestone

There are 2 main types of lime kilns: rotary kilns and vertical kilns. The heat radiated from the kiln will move upwards to dry the limestone. When coming out of the kiln, the limestone will become activated limestone.

When the limestone in the crate machine reaches a temperature of about 900 degrees C, the boiler boiler 1150 degrees C, about 30% will be resolved. At this time the need to push the water will push back to the rotary kiln. The limestone inside the furnace decomposes to CaO and CO2. Put the dissolved limestone in a chiller and cool to 100 degrees Celsius. Heat-exchanged air is about 600 degrees Celsius into the mill. Exhaust gas and cold air push into the bag vacuum cleaner, through the exhaust valve to the chimney mill.

Limestone after cooling will pass through vibrating feeder, chain conveyor, then rubber conveyor and lime warehouse.

The information just recently has answered the questions about what limestone is as well as what types of limestone, how is the calcination process. If you need to use limestone you can seek out building materials suppliers d