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Wet process of cement manufacture

Short answer

Chalk and clay are wet-ground into a slurry with 35-40% water, corrected for composition, and fed into a rotary kiln. After drying, calcination, and burning at 1400-1500°C, clinker forms, then cooled, ground with 3-5% gypsum. It ensures uniform mixing but requires more fuel.

Draw a flow chart and explain the manufacture of cement by the wet process.

In the wet process, the raw materials are ground with water into a slurry (35-40% water), which is fed to the rotary kiln. It is suitable when the raw materials are soft and wet, such as chalk and clay.

Flow chart

  Limestone/Chalk        Clay
        |                  |
   Crushing          Washing in wash mill
        |                  |
        +-----> Wash mill / Ball mill <--- water
                     |
               Slurry (35-40% water)
                     |
             Slurry tanks (correction)
                     |
           Rotary kiln (1400-1500 C)
                     |
                  CLINKER
                     |
              Cooler, then mix
              with 3-5% gypsum
                     |
                Ball/tube mill
                     |
               Cement silo
                     |
                Packing/bags

Explanation

  1. Preparation of slurry: limestone is crushed and fed to the wash mill/ball mill along with clay and water. Grinding gives a creamy slurry containing about 35-40% water.
  2. Correction: the slurry is stored in tanks, tested for CaCO3 (about 75-78%) and corrected by adding limestone or clay until the composition is right. Compressed air keeps it agitated.
  3. Burning: the slurry enters the upper end of an inclined rotary kiln (diameter 2.5-3.5 m, length about 90-150 m or more). In the drying zone the water evaporates (up to about 400 C); in the calcination zone CaCO3 breaks down into CaO and CO2 (about 900 C); and in the burning zone (1400-1500 C) the materials partly fuse into clinker nodules of 5-10 mm.
  4. Cooling and grinding: the hot clinker is cooled, mixed with gypsum (about 3-5%) and ground to a fine powder in tube mills.
  5. Storage and packing: the cement is stored in silos and packed into 50 kg bags.

Merits: easy mixing and uniform composition; less dust. Demerits: higher fuel consumption, a longer kiln, and a slower, costlier process.

✓ Answer checked by Claude Opus 5.5 (high effort)

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