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CEMENT - Coggle Diagram

- - - - Portland Cement (OPC): The standard, most widely used type. Forms cement by hydration reactions. o Blended Cements (e.g., Portland-Limestone, Pozzolanic): Mix OPC with Supplementary Cementitious Materials (SCMs).
    - - Hardens only in dry conditions or through reaction with gases (e.g., lime, gypsum plaster).
- - - - Lime Sources (Calcium): Limestone, Chalk, Shells. (Provides CaO)
      - ∙ Silica Sources (Silicon): Clay, Sand, Shale. (Provides SiO2)
      - ∙ Alumina Sources (Aluminum): Bauxite, Clay. (Provides Al2O3)
      - ∙ Iron Sources (Iron): Iron Ore, Mill Scale. (Provides Fe2O3)
  - - - Quarrying & Crushing: Raw materials are extracted and reduced to small sizes.
      - Grinding & Homogenization: Materials are mixed and finely ground into a "raw mix." 3. Calcination & Clinkering (The Core Step):
      - o Raw mix is heated in a Kiln (rotary furnace) to about 1450∘C.
      - o Calcination (CaCO3→CaO+CO2): Limestone decomposes, releasing CO2 (major source of emissions). o Clinkering: Materials chemically react to form small, hard nodules called Clinker.
      - Finish Grinding: Clinker is cooled and then ground into a fine powder.
      - Gypsum Addition: A small amount of Gypsum (CaSO4⋅2H2O) is added during grinding to control the setting time (prevents flash set).
- - - - ∙ Carbon Dioxide (CO2) Emissions: Cement production is a major contributor to global CO2 (approx. 8% globally).
      - o Sources: Calcination (chemical process) and Fuel Combustion (to heat the kiln).
      - ∙ Energy Consumption: Kiln heating is highly energy-intensive (requires significant fuel, e.g., coal, petcoke). ∙ Resource Depletion: High volume use of limestone and other raw materials.
      - ∙ Dust & Air Pollution: Fine particulate emissions during grinding and handling.
  - - - Clinker Substitution: Maximizing the use of SCMs (Fly Ash, GGBS) to reduce the clinker-to-cement ratio. ∙ Alternative Fuels: Using municipal or industrial waste fuels to power the kiln.
      - ∙ Carbon Capture and Storage (CCS): Emerging technology to capture CO2 from the kiln exhaust. ∙ Novel Cements: Research into low-carbon alternatives (e.g., Geopolymer Cements, Alkali-Activated Materials). C. Economic Importance
      - ∙ Global Industry: Massive, multi-billion dollar global market.
      - ∙ Infrastructure Driver: Essential for construction and infrastructure development worldwide. ∙ Employment: Significant employer in manufacturing, quarrying, and construction sectors.
- - - - o Fly Ash: Byproduct from coal-fired power plants.
      - o Ground Granulated Blast Furnace Slag (GGBS): Byproduct from iron/steel production. o Silica Fume: Byproduct from silicon/ferrosilicon alloy production.
      - o Calcined Clay/Metakaolin: Clay heated to form a reactive pozzolan.