LAFARGE
Cement manufacturing process

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Extraction of raw materials

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The raw materials required to manufacture cement are limestone and clay. Rocks extracted from the quarry are routed to the nearby cement plant on a conveyor belt.
Each quarry is subject to a rehabilitation plan adapted to its situation, including promotion of local biodiversity (animal and plant species), creation of a touristic and environmental park, residential or agricultural redevelopment, etc.

[Safety]

Did you know?
The use of mobile equipment (fork-lifts, trucks, mechanical loaders, power shovels, etc.) is a major part of cement plant operations. The Group has established precise recommendations to achieve and maintain a zero-accident rate. These include compulsory traffic plans, defining the operations and movements of all types of mobile equipment throughout the site (quarry, warehouses, internal rooms, etc.).

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Grinding and storage of raw materials

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The minerals from the quarry are routed to the grinding plant where they undergo initial milling before being reduced to a fine powder. The raw materials (80% limestone and 20% clay) are then stored in the pre-homogenization pile. This mixture is called the “raw mix”.
A proportion of extracted rock can be replaced by other materials (slag, fly ash, pozzolan, etc.) with a chemical composition similar to that of limestone and clay. Using these alternatives helps preserve natural resources.

[Safety]

Did you know?
Storing materials on the ground is intrinsically unstable. No pedestrian access is permitted to the piles of materials. Pedestrians are restricted and must not come within a minimum safe distance of the piles and the mobile equipment. Operators and truck drivers are also obliged to stay in their cabs during loading work.

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The firing of raw materials

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The raw mix is fed into a preheating tower at 800°C before returning to the vertical rotary kiln where it is heated to a temperature of 1450°C. Combustion causes a chemical reaction called “decarbonation” which released the CO2 contained in the limestone. The fired materials take the form of hard granules called “clinker”. By its very nature cement production has a large environmental footprint. That is why, with WWF, Lafarge has committed to reducing its global CO2 emissions.
Alternative fuels are increasingly being used to heat the kiln, for instance. These fuels, comprising waste or residues from industrial or agricultural activities, vary depending on local resources: used tires, palm kernel shells, bio-fuels, etc.

[Safety]

Did you know?
The wearing of Personal Protective Equipment (PPE) is compulsory in all areas of the site, apart from the control room. This equipment includes a hard hat, a high-visibility vest, protective goggles and reinforced boots. The wearing of a safety harness, an anti-dust mask and gloves is also required for some jobs.

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Storage and grinding of cement

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Following re-cooling, the clinker is stored in silos, then transformed into cement according to production requirements. During the final manufacturing stage, gypsum is added to the clinker, in a proportion of 3-5%, and the mixture finely ground.
Various substitute materials, such as fly ash (residue from thermal power plant activity) and slag (from blast furnaces), can also be used in the composition of cement. Their use has the dual advantage of reducing the quantity of clinker required (and so CO2 emissions linked to the manufacturing process) and creating a wider range of cements, with qualities corresponding to customers’ specific needs.

[Safety]

Did you know?
All repair work carried out on machines is subject to a decommissioning procedure. Firstly, proper preparations must be made for the repair work, identifying those responsible for the operation. Then, to isolate power, the “LOTOTO” sequence must be followed, which breaks down as “LO” (“lock out”) “physically locking away the controls using a padlock”, “TO” (“tag out”) “labeling with information about who has placed the padlock, when and why” and “TO” (“try out”) “testing to ensure that the power supply has been properly shut off without risk of reconnection”. The machines can now be inspected without danger!

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Packaging and shipment

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The cement is stored in silos before being delivered in bulk using tanker trucks or packaged into 25-35kg bags and stacked on pallets. Various means of transport may be used according to the local infrastructure and topography.
The use of transportation methods with a low carbon footprint (in particular river or rail) is given preference wherever possible. Since the market for construction materials is a local market, transportation distances are relatively short.

[Safety]

Did you know?
Road transport is among the activities with the highest accident rate. But the majority of these accidents can be avoided by following simple rules. Numerous awareness-raising campaigns and training courses are carried out in every plant aimed at employees and subcontractors, in order to improve driving safety.

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