Basic chemistry

What is cement and an example of how cement is made?

Cement types?

What is cement and an example how it is made?

Contents:

1 .Cement

2 .How cement is made

3. Crushing and grinding of raw materials

4.Mixing of materials

5.Combustion

6. Types of cements

 

1.Cement:

Before answering the question: “How to make cement?”, The concept of cement will be discussed, as it is considered a binder and one of the materials used in construction.

It collects other building materials and works to harden them and adhere to them to tie them together, and one of the concepts associated with it is concrete, which is a mixture of cement, gravel and sand that dries up and adheres to each other, and it is the most consumed resource on the planet after water, and it is considered an inorganic substance that forms

It is made of calcium silicate and can be described as hydraulic or non-hydraulic, and the word cement comes from the Romanian term meaning a building material made of crushed rocks with burning lime, and from the most countries that produce it are China and the United States of America.

[2] How to make cement:

Cement manufacturing processes are known as wet, dry and semi-dry processes.

When the raw materials are wet they are called mortar.Accurately, a number of steps must be mentioned, as follows

[3] : Crushing and grinding of raw materials

The process of crushing and grinding takes place in two basic stages, namely: crushing and grinding of dry materials, where the raw materials are dried in cylindrical rotary dryers and then they are ground in a cylindrical or circular mill containing a group of steel grinding balls , and the second stage is the crushing and grinding of soft materials by stirring

The force is used by the water in the washing mills, so that slurry is produced, and to remove large particles, it is passed through filters to obtain a fine slurry.

[4] Mix materials:

Also at this stage, two processes are carried out, one for dry materials and the other for wet materials. In the dry materials process, a preliminary plan is drawn up for the cement to be produced by controlling the amount of raw materials obtained from the crushing and grinding plant, and the resulting mixture is stored in silos so that it is ensured

Good mixing of dry materials by strong air pressure, while in the wet phase they are stored in slurry tanks, and these materials are mixed by mechanical means or compressed air or both together, and this mixture usually contains 35-45% of water and to reduce the ratio of water to 20-30% of the mixture is passed through filters; This is to reduce the amount of fuel combustion consumed.

[5] Combustion:

The predominant furnace in the incineration stage is the rotary kiln, but garbage furnaces are still used in some countries, as the rotary kilns are 200 meters long and 6 meters in diameter and are present in the wet processing plants and in the dry process.

They are lined with heat-resistant materials, and it is called the rotary because it rotates slowly on An axis inclined by a few degrees horizontally, where raw materials are added from the upper end and move downward towards the fire,

And fuel is supplied through pipes, which includes natural gas , coal or oil, as temperatures range between 1350-1550 degrees Celsius, and raw materials that have been burned .

They come out of the oven in the form of small nodules, and then they are transferred to the coolers, which process through the air.

After the burning process in the rotary kiln, the materials are transferred to the shorter rotary kiln, where the nodules come out and contain 10-15% water and when they enter the shorter rotary kiln, the water is absorbed by hot gases, and these gases may be a source of pollution to the environment and a source of inconvenience to the population, especially in populated areas. ;

Therefore sealing devices, filtration systems or electrostatic dust deposition devices are placed between the chimney and the oven outlet.

Milling after burning Raw materials pass at this stage through horizontal mills to obtain fine powder from gypsum and cement components and may pass directly through the mill, or coarse materials can be separated and returned to the mill to ensure a fine powder, and sometimes small amounts of grinding aids are added to the feeding material. .

At the end of the cement making process, it is supplied to silos for storage or placed in vacuum bags and sent in large containers for later use.

[6] Cement types:

There are many types for different uses, as there are two basic types  which are ordinary Portland cement and Portland cement.

It quickly hardens, and it is used in the event that faster hardening is required; Because it contains less water.

1.Refractory cement:

It is used in concrete buildings.

2.Expanded cement:

Expanded cement, used in the construction of prestressed concrete channels and for fixing filler bolts.

3.White cement:

White cement used for plumbing.

4.Sulfate resistant cement:

Sulfate-resistant cement, this type is used in the construction of foundations of buildings constructed on soils containing a high percentage of sulfates.

5.Portland cement:

It is mainly used in large concrete buildings, in contact buildings and hydraulic structures.

Read more:

Cement production?

Also read it:

Hydrogen is a gas and first element on periodic table?

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