Manufacturing of cement

the discussion on the manufacturing process of cement that how actually a portland cement is manufactured in cement industry

1. Concrete technology Name:Muhammad J unaid S hafi Sec:E Deptt:Civil Engg ; Roll No:168

2. Manufacturing of cement Cement is the basic ingredient of constuction and the most widely used constructing material. It is a very critical ingredient because only cement has t he capicity to enhance the viscosity in concrete. This viscocity provides an interlocking platform for all aggregates,water and admixtures.

3. Cont … Definition : The six step process by which Raw materials after a series of physical and chemical changes changes into a very fine powder like binding material is called manuf : of cement .

4. Flow chart

5. Before discussing the topic….

6. Cont …. There are manily two types of manufacturing processes: 1)Dry process(25%) 2)Wet process(75%) If we use water then it is Wet otherwise it will be Dry process.

7. Wet process

8. Wet Process(preferred to use) a)Easiest to controle chemistry and better for moist raw materials. b )Having high fuel requirements c)Pre-heater further enhance the fuel efficiency so increase the productions rates

9. Six steps;; 1)Raw materials extraction/Quarry 2) Grinding,Proportioning and Blending 3)Pre-heater phase 4)Kiln phase 5)Cooling and Final Grinding 6)Packing and Shipping

10. 1 st step) Raw materials Extraction Cement uses Raw materials that cover Ca,Si,Fe & Al. Limestone for Ca,Sand & Clay fulfills the need of Si.Fe & Al. Raw materials are extracted from the Quarry & by means of Conveyor belt materials are transported to the cement plant. There are also other Raw materials used in trace amounts,For ex;

11. Cont …. Shale(Si02,Al2O3,fe2O3) Fly Ash Mill scale Bauxite Before transportation to the plant,large size rocks are crushed into smaller size rocks with the help of crusher at Quarry. Crusher reduces large rocks to size of gravels.

12. Quarriyng

13. 2 nd step) proprtioning,blending & grinding The Raw materials from Quarry are now routed in plant where they are analyzed and proper proportioning of limestone & clay. At this stage lime stone is 80% and Clay is 20%.

14. Cont …. Now cement plant grind the raw mix with the help of heavy rollers and rotating table. Rotating table rotates continously under the roller and brought the raw mix with the roller. Roller crushes the materials to a fine powder & finishes the Job. Raw mix then is stored in a Pre-Homogenizer.

15. Crusher

16. 3 rd step) pre-heating raw materials After final grinding,the material is ready to face the pre-heating chamber. Pre-heater chamber consists of series of vertical cyclone from where the raw materials before entering into the kiln. Pre heating chamber utilizes the emitting hot gases from kiln.

17. Cont …

18. Cont …. Pre heating of the materials saves Energy and make plant environmental friendly.

19. 4 th step) kiln phase A rotary kiln is a huge rotating furnace having 7m diameter and 230m length and is slightly inclined. It is the most important and critical phase of the cement plant so it requires a proper controlling process which is the following; a)Critical parameters: Fuel,Feed b) Temprature c)Stability & Instrumentation

20. Kiln phase… a) Feeding of kiln:Delivery of a proper proportions of the Raw mix into the kiln alongwith water is called feeding of thr kiln. This raw mixture is fed ar the upper end of the kiln. b)Fuels: Kiln is heating up from the lower end or exit side by the use of natural gas and pulverized coal. The amount of coal used for manufacturing of

21. Kiln phase… Of 1 tonn (2200 lb ) cement is 100kg-350kg depreding upon the process used. The fuels can be any combustible hydrocarbons. TEMPRATURE: the temprature of the kiln is 1450*C-1500*C.

22. Kiln cont …

23. 5 th step) Clinker formation,cooling & cement making process Climker Formation:The Raw materials mixture moves down in kiln & due to high tempratures various ch ; changes occurs. a)Any water present is driven off b) Decarbonation of calcium carbonate. c)In the hottest(lower end) part of the kiln,some 20 to 30% materials become liquid & lime,silica & alumina recombine.

24. Clinker…. d) The mass fuses into balls 3-25mm in diameter is called clinker and the associated temprature is called clinkering temprature .

25. Clinker composition; A typical clinker has the following composition: CaO2=65% SiO2=20% AL2O3=10% Fe2O3=5%

26. Clinker… Cooling of the clinker:: After passing out from the kiln,clinkers are cooled by means of force air due to temprature exchange with that air. Clinker released the absorbed heat cool down o lower temprature . >>>>Released heat is reused by recirculating it back to the kiln saves ENERGY.

27. Clinker cooler

28. Clinker… Final Grinding(Rotating Ball Mill):: Final process of 5 th phase is the final grinding.There is horixental filled with steel balls.Clinker reach in this rotating drum after cooling.Here,steel balls tumble and crush the clinker to very fine powder. >>>During Grinding GYPSUM is also added t the mix in small % that controles the setting of cement.

29. Final Grinding… Rotating Ball Mill

30. Packaging and shipping The cement is then housed in storage silos,from where it is hydrualically extracted and transported to facilities where it will be packaged in sacks or supplied in bulk. In either caseit can be shipped by rail car,truck or ship.

31. Viscous paste raedy to use..