7 cement industries

• cement - A finely ground powder, usually gray, that acts as a binding agent when mixed with water and aggregates, forming concrete or mortar.
• cement is Primarily made from limestone and clay, with the addition of other materials such as iron ore, sand, or shale.
• in cement industry

  1. Chemical Reaction: Hydration
  2. Essential for construction projects, including buildings, bridges, roads, dams, and residential homes, due to its strength, durability, and versatility.
• in cement industry:

  1. The sector of the economy that specializes in the production, distribution, and sale of cement, one of the most critical materials in construction.
  2. This industry involves a complex, energy-intensive process of extracting and processing raw materials (primarily limestone and clay), heating them to high temperatures to produce clinker, and then grinding this clinker into a fine powder and mixing it with additives to produce cement.
• • Variations of cement were used up to 12,000 years ago, with the earliest archaeological discovery of consolidated whitewashed floor made from burned limestone and clay found in modern-day Turkey.
  • .The Industrial Revolution in Europe in the late 18th century saw a flurry of new developments in cement and concrete, with important contributions made by John Smeaton, who discovered that the hydraulicity of lime was directly related to the limestone’s clay content
• • In 1824, an Englishman, Joseph Aspdin, patented an artificial cement made by the calcination of some argillaceous limestone.
  • In 1845, Isaac Johnson fired chalk and clay at much higher temperatures than the Aspdins.
  • From 1850, the use of concrete made from Portland cement increased considerably.
  • By the end of the 19th century, hollow concrete blocks for housing construction became mainstream.
  • The first cement standard for Portland cement was approved in Germany in 1878.
• raw materials in cement

  1. limestone
  2. gypsum
  3. shale
  4. clay
  5. iron ore
  6. blast furnace slag
  7. sand
  8. marl
• limestone - A sedimentary rock which composed mainly of calcium carbonate (CaCO3), usually in the form of calcite or aragonite.
• gypsum - A soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO 4·2H2O. It is commonly found in layered sedimentary deposits in association with halite, anhydrite, sulfur, calcite, and dolomite.
• shale - A fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite.
• clay - A finely milled, air separated clay used as a plasticizer in mortar and render applications where sands are low in clay content.
• iron ore - Are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red.
• blast furnace slag - A calcium-silicate-based product removed from the top of molten iron during its extraction from ore in a blast furnace.
• sand - A mixture of small grains of rock and granular materials which is mainly defined by size, being finer than gravel and coarser than silt.
• marl - A fine-grained sedimentary rock consisting of clay minerals, calcite or aragonite, and silt. It is soft, light-coloured mud-like sediment seen in shallow waters of some small lakes or ponds, or under swamp lands, where it typically is covered by black organic sediment.
• In cement manufacturing, both wet and dry processes are employed to produce the final product.
• raw material preparation

  • In the dry process, raw materials such as limestone, clay, shale, iron ore, and sand are crushed and ground into fine powder. This grinding is typcally done in ball or roller mills. The finely ground raw materials are then stored in silos or storage tanks.
• Formation of Clicker

  • The powdered raw materials are fed into a rotary kiln where they are heated to temperatures ranging from 1400°C to 1450°C. The intense heat causes chemical reactions to occur, resulting in the formation of clinker nodules.
  • These nodules are essentially small, marble-sized balls composed of various minerals including calcium silicates, calcium aluminates, and calcium ferrites. The clinker nodules are then cooled and stored.
• Grinding of Clicker

  • After cooling, the clinker nodules are ground into a fine powder to produce cement. This grinding process is usually done in ball mills, which are cylindrical rotating drums filled with steel balls that grind the clinker into the desired fineness. Gypsum is sometimes added during the grinding process to control the setting time of the cement.
• Packaging and Distribution

  • The final cement product is then stored in silos before being packaged into bags or bulk containers for distribution to consumers.
  • Quality control measures are implemented throughout the process to ensure that the cement meets the required specifications.
• Wet Process Slurry Formation

  • In the wet process, the raw materials are first crushed and then mixed with water to form a slurry.
  • This slurry typically contains 30% to 40% water by mass.
  • The slurry is then pumped into a rotary kiln where it is heated to temperatures of around 1400°C.
  • The water in the slurry evaporates, and the raw materials undergo chemical reactions to form clinker.
• Clinker Formation and Cooling

  • Similar to the dry process, the high temperatures in the kiln lead to the formation of clinker nodules.
  • These nodules are then cooled and stored.
• Grinding and Packaging

  • After cooling, the clinker nodules are ground into cement powder. This grinding process may involve the use of ball mills or other types of grinding equipment.
  • Gypsum is often added during the grinding process to control the setting time of the cement.
  • The final cement product is packaged and distributed to consumers, with quality control measures in place to ensure consistency and compliance with standards.
• Portland cement

  • It has been defined as “ the product obtained by pulverizing clinker consisting essentially of hydraulic calcium silicates,
  • to which no additions have been made after calcination other than water and/or untreated calcium sulfates,
  • except that additions not to exceed 1.0 percent of other materials may be interground with the clinker at the option of the manufacturer
• Major product in cement industry

  1. portland cement
  2. pozzoulana cement
  3. calcium aluminate cement
  4. special or corrosion resisting cement
• Pozzoulana cement is a material which is not cementitious in itself but which becomes so upon admixture with lime
• Calcium aluminate cement is manufactured by fusing mixture of limestone and bauxite, the latter usually containing iron oxide, silica, magnesia and other impurities.
• Special or corrosion resisting cements are used in large quantities for the fabrication of corrosion proof linings for chemical equipment such as brick-lined reactors and others.
• Types of Portland Cement

  • type I
  • type II
  • type III
  • type IV
  • type V
• TYPE I: Regular Portland Cements - Are usual products for general concrete construction.
• TYPE II: Moderate Heat of Hardening Portland Cement -

  • Are used where moderate heat of hydration is required. -
  • Also used for general concrete construction exposed to moderate sulfate action.
• TYPE III: High Early Strength Cements -

  • Are made from raw material with high lime o silica ration. -
  • Frequently burned twice and very finely ground
• TYPE IV: Low Heat Portland Cements -

  Contain a higher percentage of tetracalcium aluminoferrite and dicalcium silicate and hence set with the evolution of much less heat.
• TYPE V: Sulfate Resisting Portland Cements -

  Are those which by their composition or processing resist chemicals better than the four other types
• Ancient Roots: Cement-like materials have been used since ancient times, with the Romans famously using a form of lime mortar
• Modern Cement: The modern cement industry began in the 19th century with the development of Portland cement by Joseph Aspdin in England in 1824.
• Industrial Growth: The industry saw significant growth during the Industrial Revolution due to increased demand for construction materials.
• Basic Raw materials

  • Limestone: Primary source of calcium, which is essential for cement production.
  • Clay or Shale: Provides silica, alumina, and iron oxide necessary for cement formation.
  • Gypsum: Regulates setting time and gives cement its final strength.
• Limestone: Primary source of calcium, which is essential for cement production
• Clay or Shale: Provides silica, alumina, and iron oxide necessary for cement formation.