Cement is a finely ground mineral powder that is typically grey. Calcium, silica, aluminum, iron, and other elements are combined chemically under strict control to create cement. Limestone, shells, chalk, or marl are frequently combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore to make cement. This guide is all about the Cement mining process.

Steps in the Cement mining process:

The mining process for cement consists of six main steps.

Step 1: Raw Material Extraction:

Limestone (calcium), sand and clay (silicon, aluminum, iron), shale, fly ash, mill scale, and bauxite are the raw materials required to make cement. The ore rocks are mined and reduced to bits no larger than 6 inches. They are subsequently reduced to the even smaller size, 3 inches, by secondary crushers or hammer mills. The ingredients are then ready for processing after that.

Step 2: Grinding, Proportioning, and Blending:

By blending them with additives and grinding them to achieve a fine homogenous mixture, the crushed raw materials are ready for the Cement mining process in the kiln. According to the desired qualities of the cement, the proportions of the cement are adjusted there. Typically, 20% of a substance is clay, and 80% is limestone. The raw mix is dried (the moisture content is decreased to less than 1%) at the cement factory. The raw mix is then blended and crushed to a fine powder, which is then stored in silos and fed into the kiln using heavy wheel-type rollers and rotating tables.

Step 3: Heating the Raw Material:

A pre-heating chamber, which consists of a series of cyclones, uses the hot gases created by the kiln. It reduces energy use and makes the cement mining process more environmentally friendly. The raw materials are moved there and converted into oxides for burning in the kiln.

Step 4: Kiln stage

The main step in the process of making cement is the kilning phase. Here, calcium and silicon dioxide compounds undergo a series of chemical reactions to create clinker from the raw mixture. Although the process is intricate, the following is the order in which the events of clinker production occur:

  1. Free water evaporates
  2. The combined water’s evolution in the argillaceous components
  3. The transformation of calcium carbonate (CaCO3) into calcium oxide (CaO)
  4. Formation of dicalcium silicate by the reaction of CaO with silica
  5. Formation of the liquid phase through the reaction of CaO with the components containing aluminum and iron.
  6. The clinker nodules’ formation
  7. Volatile substances evaporating (e. g., sodium, potassium, chlorides, and sulfates)
  8. Excess CaO reacts with dicalcium silicate to form tricalcium silicate

Based on the temperature change inside the kiln, the events above can be divided into four main stages:

  • Free water evaporates at 100°C (212°F).
  • Dehydration and the creation of silicon, aluminum, and iron oxides occur between 100°C (212°F) and 430°C (800°F).
  • The calcination process occurs between 900°C (1650°F) and 982°C (1800°F), releasing CO2 and forming CaO.
  • Creating cement clinker at 1510 °C (2750 °F).

It takes the material 20 to 30 minutes to flow through the kiln, which is tilted 3 degrees toward the horizontal. When the raw mixture reaches the bottom of the kiln, the clinker has already formed and emerges from the kiln as nodules the size of marbles.

Step 5: Cooling and Final grinding:

After leaving the kiln, the clinker is cooled by airflow from 2000°C to 100°C-200°C. To create the finished product, cement, and various additives are now mixed with the clinker that will be pulverized. Gypsum, combined with clinker and ground, controls the setting time and contributes to the compressive strength of cement, which is its most significant necessity. 

Additionally, it stops the powder from adhering to and covering the mill wall and ball surface. Several organic compounds, such as triethanolamine (used at 0.1 wt.%), help grind and prevent powder agglomeration. There are a few more ingredients that you can occasionally use, including:

  • Ethylene glycol
  • Oleic acid
  • Dodecylbenzene sulphonate

To conserve energy, the clinker’s heat is returned to the kiln. The final grinding process is the last step in creating the Cement mining process. There are rotating drums containing steel balls in the cement mill. After cooling, the clinker is moved into these spinning drums, where it is ground into a powder with 150 billion grains per pound. The finished product, cement, is this powder.

Step 6: Packing and shipping

From cement grinding mills, cement is transported to silos (huge storage tanks), bagged in 20–40 kg amounts. Only a tiny portion of the product is packaged for consumers who need small quantities. In the Cement mining process, most of the cement is carried in bulk via trucks, trains, or ships.

Supply chain and engineering solutions for cement mining

Keep your operations profitable by reducing downtime and increasing productivity. Failures are indeed all too common in the cement industry. Given the high risk of downtime, it’s essential to choose a partner who understands this industry’s unique operational and financial rhythms and maintenance. 

Prismecs has a large workforce in the Chinese and African markets, ready to minimize downtime and increase throughput in your cement mining operations. As mining becomes more data-intensive, operators need partners to help bridge the technology and productivity gaps. Prismecs is your agile, one-stop partner with a robust supply chain and experience in the Boots on the Ground field. 

So, call us today at 18887747632, or you can also write us an email at sales@prismecs.com for more information!

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