Cement industry

This is about brief introduction of the cement manufacturing and processing in industry

1. Cement industry An industry for producing a material of ever increasing demand

2. Contents Introduction to cement industry Raw materials Location of cement industry(In Pakistan) Manufacturing of cement Setting of cement Applications of cement Advantages and Disadvantages of cement

3. GROUP MEMBERS NAME HAFIZ MUHAMMAD UBAID ARIF ALI ZIA ALI HAIDER RIZI WAJID HUSSAIN MUHAMMAD TAHIR MEHMOOD

4. INTRODUCTION DEFINITION: A material obtained by burning a mixture of calcarious and argillaceous material at sufficiently high temperature to produce clinkers. These clinkers are then ground to a fine powder Important building material Applied everywhere in the construction of houses ,public buildings ,roads, industrial plant ,dams ,bridges and many other structures .

5. HISTORY A building material which was firstly introduce by English scientist Mason joseph Aspdin . He found it when strongly heated mixture of limestone and clay was mixed with water and allowed to stand. It hardened to stone like mass which resembled Portland rock(a famous building stone of England. The name of Portland cement is given to mixture of lime(obtained from limestone), silica, iron, alumina.

6. RAW MATERIAL Important raw material used for the manufacturing of cement are: ( i ) calcarious material (ii) argillaceous material CALCARIOUS MATERIAL Limestone Marble Chalks Marine shell These are the source of calcium oxide

7. Argillaceous material Clay Shale Stale Slag Aluminate Silicate

8. AVERAGE COMPOSITION OF GOOD CEMENT

9. Location of cement industries Currently many cement industries are located in Pakistan in different areas, however some of the obvious ones are: Bestway LTD (two in KPK and one in Punjab) Nishat Group (Two in Punjab and one in Baluchistan) Fauji Foundation( Two in Islamabad and one in Peshawar) Askari cement limited( Nizampur and wah) Pioneer Cement limited(Punjab)

10. Manufacturing of cement Manufacturing of cerement by two ways Dry process wet process Most industries use wet process for cement manufacturing involving following steps: Crushing and grinding of raw material Mixing of material in correct proportion Grinding the heated product known as clinker Mixing and grinding of cement clinker with gypsum

11. Crushing and grinding In the presence of water in rotating cylindrical balls and tube mills 2. Mixing of Raw material Limestone 75%, Clay25% Homogenized by using air compressed arrangement Water content is reduced from 45% to 30%

12. 3. Heating the slurry in rotary kiln Three different zones Pre-heating zone : The clay is broken down into Al 2 O 3, SiO 2 and Fe 2 O 3. Decomposition zone : lime stone decomposes into lime and CO 2 CaCO 3 CaO + CO 2 Burning zone : Oxide combine with silica to form silicates CaO + SiO 2 CaSiO 3 Cooling zone : The charge of silicates is cooled up. Greyish black clinkers are obtained

13. Grinding the clinkers with gypsum Cement Clinkers are air-cooled. 2% gypsum is first ground and then mixed with clinkers. 5. Storage and bagging Finished cement is pumped to storage silos where it is packed into paper bags and dispatched for bulk containers.

14. Setting of cement

15. Setting of Cement The conversion of a paste of cement to a rigid mass is known as Setting of cement.

16. Hydration Cement is mixed with water C 3 A + 6H 2 O C 3 A . 6H 2 O E= -880 kJ/Kg Hyderated Tricalcium Aluminate To avoid early setting of C 3 A , Gypsum is added which acts as retarding agent. C 3 A + 3CaSO 4 . 2H 2 O C 3 A . 3CaSO 4 . 2H 2 O Caclium Sulpho Aluminate

17. Hydrolysis After hydration, Hydrolysis of C 3 A, C 3 S starts to give tobermonite gel and crystalline Ca(OH) 2 , which is responsible for initial strength of the cement . The Hydrolysis of C 3 S gets completed within 7 days 2C 3 S + 6H 2 O C 3 S 2 . 3H 2 O + 3Ca(OH) 2 Reaction:

18. Setting Time of Cement Initial Setting Time The initial time refers to the time that cement turns into paste by mixing with water and begins to lose its plasticity. 30≥45 Final Setting Time The time that cement completely loses its plasticity by mixing with water and begins to have a certain structural strength is known as the final setting time. ≤10hrs

19. Factors Affecting the Setting Time Of Cement Composition of cement. Amount of gypsum in cement Fineness of cement Water Cement Ratio Type of admixture used Storage of cement

20. To prepare cement mortar To prepare cement concrete To build fire proof and thermal proof structures To build hydrographic and frost resistant structures To construct Cement concrete roads For aesthetic concrete construction Application of Cement

21. Mortar is a workable paste which hardens to bind building blocks such as stones, bricks, and concrete masonry units, to fill and seal the irregular gaps between them, spread the weight of them evenly, and sometimes to add decorative colors or patterns to masonry walls Cement As Mortar

22. In its simplest form,  concrete  is a mixture of paste and aggregates.  Cement  is actually an ingredient of  concrete . It is the fine powder that, when mixed with water, sand, and gravel or crushed stone (fine and coarse aggregate), forms the rock-like mass known as  concrete . Cement As Concrete

23.   To with stand against high temperatures and to prevent fire accidents structures should be built with great fire-resistant materials like cement. High alumina cement is more suitable material to make concrete for the structures in high temperature regions. To Build Fire Proof or Heat Proof Structures

24. Most of the hydrographic structures in the world are built using concrete with cement as binding material. The structures built in water or in contact with water should be very strong against moisture and they should be water tight. To Build Hydrographic and Frost Resistant Structures

25. Cement concrete roads are more famous as high standard roads which are stronger than all other types of roads. They are also called as rigid pavements because of their rigid nature. C.C roads have long life span even without proper maintenance. Load wise also they are much capable than all other types. To Construct Cement Concrete Roads

26. Now a days cement is available in many colors. This is done by adding coloring agent while manufacturing cement but the percentage of coloring agent should be below 10%. Some of the coloring agents are iron oxide which gives red or brown, cobalt which gives blue etc. The colored cement makes the structure beautiful without any painting. Colored cements generally used for floor finishing, stair treads, window sill slabs, external wall surfaces etc.. For Aesthetic Structures

27. A dvantages and Disadvantages of Cement Presented By: M Tahir Mehmood Roll No: Bsf-1702589 Semester: 7 th (Morning)

28. A dvantages Of Cement 1. The cement has good plasticity before coagulation and can be poured into various shapes and sizes of components or structures . 2.Fire Resistance Cement has a slow rate of heat transfer, which means that concrete walls in a home act as a fire shield. 3. Durability Durability of cement is ability to resist weathering action and chemical attack. Types of durability: Physical Durability is against freezing and thawing action, permeability of water, temperature stress. Chemical Durability is against alkali aggregate reaction, sulphate attack, chloride ingress etc .

29. A dvantages Of Cement (Cont.) 4. Cement is resistant to wind and water. Therefore, it is very useful in storm shelters. 5. cement is free from defects and flaws. 6. It has high thermal mass(moderates' temperature) 7. Materials used in the production of concrete are easily available. 8. It can be sprayed and can be used to rectify small cracks. 9 . It can be pumped and placed even in very difficult locations. 10. It provides quickness and ease in the construction of monolithic members of the structures.

30. Disa dvantages Of Cement 1.C racking: Shrinkage is a main cause of cracking. As concrete hardens and dries it shrinks. This is due to the evaporation of excess mixing water. This shrinkage causes forces in the concrete which literally pull the slab apart. Cracks are the result of these forces. To avoid the development of cracks, steel is used as reinforcement. 2. Cement is less ductile. 3. Compared to other binding materials, the tensile strength of cement is relatively low.

31. Disa dvantages Of Cement (Cont.) 4. It contains soluble salts. Soluble salts cause efflorescence. 5. Cement is not fully impermeable material. 6. It is not ideal for situation when settlement is expected. 7. Due to the more weight of concrete, more reinforcement is needed, which increases the cost of the structure. 8. It is very sensitive with water content in the mixture. 9. Long curing time( Cure time is the time that determines how long things take to fully cure ).  

32. References www.apcma.com/data_productioncapacity.html www.cmaindia.org/blogs/the-cement-manufacturing-process/