Cement Manufacturers Association (CMA)

39 Refractories in the cement industry Cement has played a very crucial role in the journey of mankind right from caves to skyscrapers. It has a lion’s share in the development and progression of modern civilization as a material for the construction of tall structures, tunnels, bridges, schools, hospitals, dams, and buildings of utmost importance such as the parliament of the country. Almost every human-made structure that is used in different domains of life can be attributed to cement. Cement is manufactured by a high-temperature reaction of shale with calcium oxide of limestone or chalk to frame solidifying stages like dicalcium silicate and tricalcium silicate. This reaction happens inside a reactor which is known as kiln. Refractories play a crucial role when it comes to containing high temperatures inside the furnace and different types of other equipment, and consistently making manufacturing possible on a large scale. A refractory lining inside the reactor keeps up with the temperature range of the reactor within a moderate limit. The refractory covering likewise restrains the heat flow from within the reactor to the outside and consequently helps save energy, which offers cost-effectiveness to the process. Without the availability of proper refractory solutions, it is almost impossible to produce cement on a large scale, in a cost-effective manner. Effective usage of refractory in cement industry Specialized Refractories for Cement Manufacturing The cement industry has unique demands that require specialized refractories. As more alternative fuels are used, refractory solutions become even more critical. Various National and Multinational organizations, excel in delivering refractory products that enhance the profitability for cement manufacturers worldwide. Their refractories perform better, last longer, and offer lower refractory costs per ton of clinker produced. Kiln Lining Considerations When it comes to kiln lining, both standard and alternative fuels need careful attention: • Brick or Monolithic?: Except for the inlet cone and the nose ring, kilns should primarily be lined with bricks. The choice of brick heights depends on the kiln diameter, typically ranging from 200 mm and above. • Fuel Efficiency and Waste Fuels: Modern kilns are shorter but maintain high production capacity. Many producers use kilns to burn waste materials, which provide low-cost energy. However, widespread use of alternative fuels poses challenges for refractories. High- temperature areas, usually lined with basic bricks, require higher refractoriness, alkali-and thermal shock resistance, and better resistance to clinker liquid phase corrosion. • Tire Rings: During kiln startup, allow time for the tire rings to expand in pace with the kiln shell. Rapid heat-up can cause shell deformation, potentially damaging refractories. Later, when the tire rings expand to full operating dimensions, they can lead to “rolling ovality” in the kiln shell, resulting in radial abrasion and lining loss. Energy Conservation and Productivity Refractories contribute significantly to energy conservation in cement manufacturing. By insulating the reactors and minimizing heat flow from inside to outside, refractory linings help maintain optimal temperatures. This energy conservation enhances productivity and overall profitability. Common Applications of Refractories in Cement Industry Refractory materials find extensive use in various areas within the cement industry: • Cement Kilns: These high-temperature zones are critical for clinker production. • Rotary Kilns: Used for calcination and sintering of raw materials. • Cement Plants: Refractories line various equipment and structures. • High-Temperature Furnaces: Essential for cement production. • Roads & Highways: Refractories are used in road construction. • Preheater Systems: Optimize heat exchange and energy efficiency. Choosing the right refractories is essential for efficient cement production. Whether you’re