About cement industry
What is Cement?
Cement is a binder, a substance used for construction. It sets, hardens, and adheres to other materials to bind them together. Cement is a fine powder that acts as the glue holding concrete together when mixed with water, sand and aggregates
How is Cement Produced?
The cement manufacturing process involves three phases: • The mining and preparation of inputs. • The chemical reactions that produce clinker. • The grinding of clinker with other additives to produce cement.
Mining the raw material
Limestone and clay are extracted from rock quarries thanks to the modern technology employed.
- Transporting the raw material: Once the materials have been fragmented, they are transported to the plant in dump trucks or by conveyor belts.
- Crushing: The quarry stone is delivered through chutes to the crushers, where it is reduced by crushing or pounding to chunks approximately 1 1/2 inches in size.
- Pre-homogenization: Pre-homogenization is the proportional mix of the different types of clay, limestones, or any other required material.
- Raw material storage: Each of the raw materials is transported separately to silos, where it later will be added in specific amounts according to the particular type of cement being produced.
- Raw material mill: This process takes places in horizontal ball mills, the raw material (Limestone, Clay & correction material) is ground by different-size steel balls while it works its way through the mill’s chamber.
- Raw meal homogenization: This process takes place in silos fully equipped to obtain a homogenous mix of the material.
- Calcination: Calcination is the core portion of the process, in which huge rotary kilns come into play. Inside, at 1400 degrees C, the raw material is transformed into clinker: small, dark grey nodules 3-4 centimetres in diameter.
- Cement milling: The clinker is ground by different-sized steel balls while it works its way through the mill’s two chambers, with gypsum being added to extend cement setting times.
- Cement packaging and shipping: The cement is then housed in storage silos, from where it is hydraulically or mechanically extracted and transported to facilities where it will be packaged in sacks or supplied in bulk. In either case, it can be shipped by rail car, freighter truck or ship.
Limestone+ sand+clay
Mixed in rotating kiln at 1450ºc
Cement clinker cooled+grounded = cement
Cement & the Environment
- The fuels combusted to heat the kiln account for about 40% of total cement manufacturing emissions.
- The remaining 60% are “process emissions” — i.e. when limestone is superheated, it releases CO2 in the kiln — that are effectively irreducible.
- The Cement Division of the Federation of Egyptian Industries is pursuing a variety of innovative measures to further reduce its carbon footprint, notably working with the Egyptian government, as well as regional and international institutions to create Egypt’s road map for CO2 reduction.
- The Industry’s implementation of the road map -in cooperation with the EBRD for the use of alternative fuel from solid waste- will reduce the cost of production as well as reducing carbon emissions and the consequent positive effects on the environment.
- It requires a change in the system of waste management at the state level, requiring new legislation and amendments to existing legislation.