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Q77 (NDA-II/2012) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Applied everyday chemistry Answer Verified

The most important raw materials used in the manufacture of cement are

Result
Your answer: —  Â·  Correct: B
Explanation

The manufacture of cement primarily relies on three essential raw materials: limestone, clay, and gypsum. Limestone serves as the primary calcareous material, providing calcium carbonate which is the cornerstone of cement production [1]. Clay (or shale) acts as the argillaceous component, supplying necessary silica, alumina, and iron oxides. These materials are crushed and heated in a rotary kiln at temperatures between 1400-1600°C to form cement clinker. Finally, approximately 2-5% gypsum (hydrous calcium sulphate) is added during the grinding process to act as a retarder, controlling the setting time of the cement [2]. Other options like potassium nitrate, charcoal, and sulphur are components of gunpowder, while sodium carbonate is used in glass manufacturing, making option 2 the only accurate description of cement's core constituents.

Sources

  1. [1] Geography of India ,Majid Husain, (McGrawHill 9th ed.) > Chapter 7: Resources > Natural Resources of India > p. 24
  2. [2] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 13: Types of Rocks & Rock Cycle > 13.5. Some Rock-Forming Minerals > p. 175
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SIMILAR QUESTIONS

NDA-I · 2011 · Q25 Relevance score: 0.89

Which one among the following is the main ingredient in cement ?

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Gypsum (CaSO4.2H2O) is added to clinker during cement manufacturing to

NDA-I · 2008 · Q34 Relevance score: 0.33

What is a mixture of potassium natrate, powdered charcoal and sulphur called?

IAS · 2025 · Q31 Relevance score: -1.27

Consider the following statements : Statement I : Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions. Statement II : Silica-bearing clay is mixed with limestone while manufacturing cement. Statement III : Limestone is converted into lime during clinker production for cement manufacturing. Which one of the following is correct in respect of the above statements?

NDA-I · 2021 · Q43 Relevance score: -1.68

Which one of the following is not used as a raw material in the manufacture of glass?