The cement is a fine mineral powder obtained after a very precise manufacturing process. Mixed with water, this powder forms a pulp that freezes and hardens, even under water. Depending on the composition and fineness of the powder, the properties of the cement are not the same.
The cement is the main component of concrete and lends it a number of properties, including strength. It is a high quality economical building material that is used in construction projects all over the world.
The cement is obtained by grinding and baking a mixture of limestone and clay at 1450 Celsius degrees. Called clinker, this granular material is essentially a combination of lime, silica, alumina and iron oxide.
Carthage Cement manufactures and commercialize various categories of cement, depending on the chemical composition of the raw materials, the possible additions of complementary components at the time of grinding and the fineness of the product.
Each category of products corresponds to specific purpose such as residential constructions, art works construction, underground works or even concretes submitted to aggressive environment.
The cement produced by Carthage Cement meets precise quality criteria and are subjected to regular and thorough controls at each stage of the manufacturing process. This allows it to guarantee the conformity of the end-product to the quality known standards.
Limestone and clay are extracted from quarries located near cement plants.
Blown off with rocks and boulders, limestone and clay are carried by large trucks to crushers in order to reduce their size and get stones with a diameter less than 10 cm. These raw materials are subject to rigorous selection. Their composition should include lime, silica, alumina and iron oxide in well-defined proportions.
Once crushed, the materials undergo a pre-mixing process in the pre-homogenization rooms, which make it possible to obtain a greater regularity of composition.
The materials are then dried and crushed in a grinder (ball or roller mill) in order to reduce their size to a few tens of microns. The crossing of the oven gases into the grinder allows the materials to dry. The fine powder then obtained is called raw meal, hence the expression of raw mill.
Throughout the process, features like sampling, transport and chemical analysis continuously check that the proportions of the material materials correspond to the desired chemical composition.
The meal introduced in a powder like form in a preheating tower where it is preliminarily heated by the gases produced in the rotating oven (pre-calcination phase).
Under the influence of the gravity, the flour thus goes down against the flow of the hot oven gases. The tower has several cyclone stages, which makes it possible to increase the temperature of the flour up to 850 Celsius degrees (dry-way process). The flour will then be fed into an inclined rotating oven that is packed with refractory bricks. The oven is supplied with heat thanks to a large capacity burner. The flame temperature reaches over 2000 Celsius degrees.
During this cooking process, there are many complex chemical reactions undergoing. Firstly, the limestone decarbonizes under a heat temperature close to 950 Celsius degrees and then transforms into lime, while the clays decompose into silicates and aluminates. The whole set is then recombined in silicates and aluminates of lime at a temperature of about 1450 Celsius degrees.
This chemical process leads to the production of a semi-finished product called clinker, which has the hydraulic binder properties.
The clinker is then conveyed through the cooler where it restores a good part of its thermal energy and is cooled by 100 Celsius degrees blowing air.
The chemical composition and homogeneity of the material at the oven entrance, as well as its regularity over time, are fundamental elements in the conduct of the production process. The oven has bag filters that filter dust that ensure limiting discharges to the environment.
The clinker is stored in halls (or silos) and then, in a new grinding stage, passes through ball mills. Its rotation causes, by shocks and crushing, the cut into very fine grains.
The obtained powder is cement.
Gypsum is added to regularize the setting time of the cement. Further additions can be made: limestone filler or flying ashes (issued from coal combustion in the thermal power plants) in order to improve workability and consistency, blast furnace slags (sub-products of steel mills), or even natural or artificial pozzolans to improve hydraulic properties.
The obtained cement is stored in silos of several thousand tons that are sometimes divided into compartments allowing the preservation of several cement qualities.
It is then delivered in bulk or bag.
Carthage Cement is equipped with state-of-the-art equipment, enabling it to ensure smooth processes, easy handling and a cost-effective production.
1. Crusher
The raw material is fed into a hammer and impact crusher (type EV) through two separate vane distributors in order to bring the two mixtures according to the predetermined set of instructions.
| Design / specifications | |
| Crusher | EV 200X300 |
| Production flow | 1300 t/h |
| Alimentation (dim max) | 1500 mm |
| Production (dim) | Max 5% +96 mm |
2. Raw crushing (ATOX)
For crushing raw materials, a Vertical ATOX vertical mill is used.
The ATOX raw material mill uses the pressure and the generated shear between the rollers and the turntable to crush and pound the raw materials. The feed material is directed onto the grinding table by the feed chute. The rotation of the grinding table accelerates the material towards the grinding track and passes it under the rollers.
The gas passing through the mill reaches the separator (type RAR-LVT) with very high separation performance.
| Design / specifications | |
| Broyeur | ATOX 50.0 |
| Séparateur | RAR-LVT 52.5 |
| Débit production | 455 t/h (sec) |
| Alimentation |
0% >175mm MAX. 2% >150mm Min. 30% >25mm |
| Finesse du Cru Max | 12% + 90µm |
3. Silo homo and Food Oven
| Design / specifications | |
| silo | CF 20 x 58 |
| Diamètre du Silo | 20 m |
| Section haute du silo | 58 m |
| Capacité silo (chaque) |
22,000 t ~ 2.4 jours consommation |
| Système alimentation four | Élévateur avec dépoussiéreur |
4. Oven and cooler
| Design / specifications | |
| Capacité Four | 5800 t/j |
| Préchauffeur | 2 lignes 5 étages ILC |
| Taux de calcination | 55-60% |
| Dimension four |
3-base Ø5.0m x 78m |
| Bruleur Principal | Duoflex pour petcoke et gas |
| refroidisseur | SF 4x6 cross-bar |
| température clinker | 65°C (+ ambiante) |
| Conception refroidisseur pour | 5800 t/d |
| Débit transport refroidisseur | >5800 t/d |
| Filtre de Dépoussiérage | A manches |
| Émissions refroidisseur | Max. 25 mg/Nm^3 |
5. Preheater, calciner and oven
Preheater :
The chosen configuration offers an energy-saving solution that takes into account the moisture content of the raw meal as well as the tower dimensions.
Online Calciner:
On-line calciners have lower NOx emissions than in-line calcination furnaces, since all exhaust gases from the furnace must pass through calcination.
Oven with three supports:
The 3-base oven is a high-quality rotary oven with three traditional supports.
Duoflex burner:
The DUOFLEX ™ burner triggers rotary ovens with pulverized pet-coke, natural gas or any mixture of these fuels.
The DUOFLEX burner is unique. It in fact carries a central duct for gaseous and liquid fuels placed inside an annular coal duct.
6. Clinker cooler. SF Cross-Bar
| Design / specifications | |
| type | SF 4 X 6 |
| Degré de chargement | 41.8 t/d/m² |
| Air soufflé | 1.96 Nm3 air/kg clinker |
| Nombre de ventilateurs |
9 |
| Inclinaison refroidisseur | 4° |
| Température clinker | 65° C (au dessus de l’ambient) |
7. Pet-Coke Shredder
For crushing of pet-coke, a TIRAX-type grinding is proposed. It is a fully ventilated system in a closed circuit.
| Design / specifications | ||
| Broyeur | TM 42x7.25+3.6 | |
| Séparateur | RTKM 25 | |
| Filter broyeur | Bag filter | |
| Limites alimentation (dim) | Max. 5% > 25 mm | |
| Type ppet-coke Pet coke | Pet coke | High volatile bituminous |
| Débit de Production | 33 t/h (sec) | 45 t/h (dry) |
| Finenesse produit | Max. 3% | Max. 12% + 90 um |
| Humidité alimentation | Max. 8.0% | Max. 8.0% |
| Max. Capacité séchage | de 8.0% to 1.0% humidité | de 8.0% to 1.0% humidité |
8. Atelier Crushing Cement
UMS Cement grinder:
| Design / specifications | |
| broyeur UMS | 50 x 15.0 |
| Séparateur | Sepax 425 |
| Débit production | 155 t/h |
| Finesse |
320 m² /kg (Blaine) |
| Product temperature | 105°C |
| Collecteur | Filter à manches |
| Filtre broyeur | Filter à manches |
Closed circuit:
The circuit includes a very high performance SEPAX 3rd generation separator.
9. Bagging Unit
Each bagging unit has the following characteristics:
