This document discusses energy efficient technologies for the cement industry in India. It provides background on types of cement and the cement production process. The cement production process is energy intensive, consuming around 80% of its energy during the clinker production stage. The document outlines statistics on cement production and energy consumption in India. It then discusses various energy efficient equipment, management practices, and alternative fuels that can reduce energy usage. These include waste heat recovery systems, improved kiln insulation, and use of biomass and industrial wastes as fuels. The document also discusses using fly ash and rice husk ash as supplementary cementitious materials in blended cements, as well as synthesizing nano silica from rice husk ash to improve cement properties.

2. Techno economically viable new
energy efficient technologies for
cement industries
Dr. Kanagamani Thangavel
Chief Scientist
Corrosion Science & Engineering Division
CSIR- Central Electrochemcial Research Institute, Karaikudi.

3. Types of cement
Ordinary Portland cement (OPC)
Portland pozzolana cement (PPC)
Portland slag cement (PSC)
White Portland cement (WPC)
Sulphate resistance cement (SRC)
Chemical composition of cements Wt%
Compound OPC PPC PSC
Silicon-di-oxide (SiO ) 20–21 28–32 26–30Silicon-di-oxide (SiO2) 20–21 28–32 26–30
Aluminium oxide (Al2O3) 5.2–5.6 5.0–8.0 9.0–11.0
Ferric oxide ( Fe2O3) 4.4–4.8 4.9–6.0 2.5–3.0
Calcium oxide (CaO) 62–63 41–43 44–46
Magnesium oxide (MgO) 0.5–0.7 1.0–2.0 3.5–4.0
Sulphur-tri-oxide (SO3) 2.4–2.8 2.4–2.8 2.4–2.8
Loss on ignition (LOI) 1.5–2.5 3.0–3.5 1.5–2.5
ASTM C150 / C150M - 12 specify the Standard Specification for Portland Cement

4. Cement production – 1.0 ton
- 1.5 tons earth minerals
- 1.0 ton of CO2
CaCO3 --------------- CaO + CO2
Global warming
3 2
Calcium Calcium Carbon
carbonate oxide -di-oxide
The greenhouse gas effect leads to the ozone layer
depletion and global warming.

5. Cement manufacturing process

6. Cement Production Processes
Raw materials preparation
Primary and secondary crushing of quarry
materials
Drying the materials
Grinding through either wet or dry process
Energy consumption <5%
Clinker productionClinker production
Energy intensive step
Energy consumption 80%
Wet or dry process
Finish Grinding
Mixed with additives
(Gypsum, anhydrite, pozzolona, fly ash, blast
furnace slag)

7. Cement Production in India
India – Second largest producers of cement
2003 - 115 million metric tons
Average annual growth rate 8% (1981 – 2003)
2020 - 425 million metric tons2020 - 425 million metric tons
Energy consumption – Primary energy 1100 to 1700 PJ
-- Final energy 1500 to 2100 PJ

8. List of Popular Cement Plants in India
India Cement
JK Cement Limited
Jaypee Group
Century Cement
L & T CementL & T Cement
ACC Limited
CCI Cement Plants
Gujarat Ambuja Cement Plants

9. 700000
800000
900000
1000000
1100000
1200000
1300000
1400000
Statistical comparison of cement production in India
from 1991 to 2008 - Line ChartCementProduction
Thousand Tons
A B C D E F G H I J K L M N O P Q R
0
100000
200000
300000
400000
500000
600000
080706050403020100999897969594939291
CementProduction
Year

10. Average and best practice energy consumption
values for Indian cement plants by process

11. Top Contributor States in Cement Production
States No. of cement plants Production million
tons
Madhyapradesh 19 26.23
Andrapradesh 20 17.00
Rajasthan 16 35.79
Gujarat 12
Tamilnadu 10
Countries
Export quality Bangaledesh
Nepal
Sri Lanka
Myanmar
UAE
Singapore

12. Cement industry energy consumption
Year Cement
production
(million metric
tons)
Energy consumption
Primary
energy
PJ
Final energy
PJ
1992 58 261 195
2002 110 466 352

13. NCCBM : National Council for Cement and Building
Materials
Energy Consumption - 25 to 30%
Savings upto - 164 k.cal/kg of clinker
16.4 kWh/ton of cement
Potential cost savings - 4.40 million to 66.20
million annually

14. Energy Efficient Equipment
Slip power recovery system
Variable voltage and frequency drives
Grid rotor resistance
High efficiency separator
High efficiency grate coolers
Energy Efficient Management and process
control optimization
Plugging of leakages in Kiln and pre-heater circuitPlugging of leakages in Kiln and pre-heater circuit
Raw mill and coal mill circuits
Installation of improved insulating bricks
Effective utilization of hot exit gases
Optimization of Kiln operation
4.8 to 4.2 GJ/t (P.E)
3.6 to 3.1 GJ/t (F.E)
Utilization of waste heat – Generation of electricity
3 to 5.5 MW in 20 surveyed cement plants
200 MW - 45 plants (1 million tons per year)
Alternate and waste fuels – lignite, pet coke, tyres, rice husk,
groundnut shell,

15. Energy efficient technologies
• Alternate materials for cement
• Activated fly ash cements
• Use of composite cements – binary / ternary• Use of composite cements – binary / ternary
Cements
• Production of nano silica from rice husk ash

16. Blended cements are produced by the addition of
supplementary cementitious materials:
Blended cements : Supplementary cementitious materials
S.No Supplementary materials Source industry
1 Fly ash Thermal power station
2 Rice husk ash Rice Industries
3 Blast Furnace slag Iron and steel
IndustriesIndustries
4 Silica fume Ferro silicon industries
5 Bagasse ash Sugar industries
6 Metakaolin Natural clay material
These supplementary cementitious materials possess properties which impart
certain desirable characteristics to the concrete mix which can enhance the
strength and durability of concrete structures

17. No of thermal power stations in India : approx. 72
Fly ash production in India : 100 – 150 million tons/ year
Fly ash utilization in India : 2 million tons per year
Statistical data on Fly ash
Advantages :
Larger savings in cement
Reduced heat of hydration
Greater durability

18. Activation of fly ash : to improve the reactivity
Physical activation
Thermal activation
Blended cements
Thermal activation
Chemical activation

19. n =2
n > 3
OPC
ACTIVATED FLY ASH
Activation Mechanism
Cement
Fly ash
n =1FLY
ASH

20. MECHANISM OF ACTION BY CHEMICALLY ACTIVATED FLY ASH
Neutralization of surface silanol group
Si OH + NaOH = Si ONa + H2O ------ (1)
The solubility of Na+ is more than that of Ca2+
This neutralisation repeats on new surfaces, known as corrosion of fly ash.
Gradual destroying of inside silane chain, resulting in [(Si,Al)O4]n disintegration
Si O Si + 2NaOH = 2( Si ONa) + H2O ------ (2)
Si ONa is replaced by Ca2+ , forming sedimentary calcium silicate hydrate.Si ONa is replaced by Ca2+ , forming sedimentary calcium silicate hydrate.
Si ONa + Ca2+ = Si O Ca + Na+
or (CSH) ------- (3)
2( Si ONa)+ Ca2+ = 2( Si O Ca) + Na+
or (CSH) ------ (4)
Repeating the above reactions, it can accelerate fly ash activation.

21. Parameters RHA BA
Production in India /
year
35 million tons 300 million tons
Quantity of ash
produced / 1000 kg
200 kg 150 kg
SiO2 content 93% (87%) 73 % (64%)
Carbon content for
processed ash
2.1% 4.9%
Critical parameters for processed RHA and BA
processed ash
Grain size 3.8 microns 5.4 microns
Specific surface area 36.47 m2/gm 10.50 m2/gm
Improved properties for 30% RHA and 20% BA
Water permeability 35% reduction 40% reduction
Sorptivity 45% reduction 20% reduction
Chloride diffusion 30% reduction 50% reduction
Chloride permeability 75% reduction 55% reduction

22. OPC
OPC+PPC
50%
50%
PPC OPC+PSCOPC+PPC
50%
50%
25%
Flow chart for preparation of
Binary & Ternary Cements
PSC
PPC
PPC+PSC
OPC+PSCOPC+PPC
+PSC
50%
50%
50%
25%

23. All the cements are commercially available
Ternary system showed improved
mechanical properties and better
protection for steel in concrete.
Binary and Ternary cements
protection for steel in concrete.
Ternary cements are not cost effective but
effectively durable

24. Synthesis and Properties on
nano silica concrete
• NS – RHA – Precipitation method
Mechanical Properties…..
Physical properties……
Corrosion resistant properties…..

25. Ten grams of RHA samples were stirred in 80 ml
distilled 2.0, 2.5 and 3.0 N sodium hydroxide solution,
respectively.
RHA was boiled in a covered 250 ml Erlenmeyer
flask for 3 h.
The solution was filtered and the residue was
Synthesis of pure silica from rice husk ash
The solution was filtered and the residue was
washed with 20 ml boiling water.
The filtrate was allowed to cool down to room
temperature and added 5 N H2SO4 until pH 2 and
then added NH4OH until pH 8.5 allowed to room
temperature for 3.5 h.
The filtrate was then dried at 120oC for 12 h.

26. Pure silica was extracted by refluxing with 6 N HCI for
4 h and then washed repeatedly using deionised water
to make it acid free.
It was then dissolved in 2, 2.5 and 3.0 N NaOH by
continuous stirring for 10 h on a magnetic stirrer and
then concentrated H SO was added to adjust pH in
Preparation of nanosilica
then concentrated H2SO4 was added to adjust pH in
the range of 7.5-8.5.
The precipitated silica was washed repeatedly with
warm deionised water until the filtrate became
completely alkali free.
The washing process continued by deionised water
repeatedly and dried at 50oC for 48 h in the oven.

27. SEM micrograph for Nano
silica

28. 40
45
50
55
60
65
CompressiveStrength,MPa
3 days
7 days
14 days
28 days
Compressive strength of NS cement mortar
Mix design : 1:2.75
w/c ratio : 0.52
Size : 50 x 50 x 50 mm
0.0 0.5 1.0 1.5
0
5
10
15
20
25
30
35
CompressiveStrength,MPa
% of Nano Silica

29. SYSTEM Strength (N/mm2)
3 days 7 days 14 days 28 days
Split Tensile Strength of NS admixed
cylinders (ASTM C496-90)
Mix design : 1:2.75
w/c ratio : 0.52
Size : 60 mm dia. x 100 mm height
3 days 7 days 14 days 28 days
CONTROL 1.908 2.76 2.76 2.76
NS1 (0.5 % NS) 1.908 2.97 2.97 2.97
NS2 (1.0 % NS) 2.12 2.97 3.18 3.18
NS3 (1.5 % NS) 1.802 2.97 2.97 2.97

30. Synthesis of nano silica
Nano silica is synthesized from Rice Husk Ash
(RHA- an industrial waste) by precipitation method.
Nano Silica
Compressive strength (N/mm2)
Compressive strength of NS cement mortar
SYSTEM 3Days 7 days 14 days 28 days
CONTROL 9 10.8 13.6 24.9
NS1(0.5%NS) 13.2 15.6 21.2 45.3
NS2(1.0%NS) 18.3 20.4 24 61.6
NS3(1.5%NS) 20.1 22.0 23.2 40.8

31. The compressive strength of mortar is increased by 2.5 times
after 28 days of curing at 1% NS level. More over irrespective of the
period of curing (3, 7 and 14 days) the compressive strength of
mortar actually doubled at 1.0% NS level.
The split tensile strength of mortars showed a marginal increase
at 1.0% NS level.
Nano Silica
The bulk and apparent density of cement mortars also showed a
marginal increase at 0.5%, 1.0% and 1.5 % NS levels.
Sorptivity results indicated that a considerable decrease (50%)
observed at 1.0% NS level when compared to 0.5% NS level.
RCPT test results showed that a considerable decrease in charge
passed (6%, 8% and 15% for 0.5%, 1% and 1.5 % NS level
respectively).

32. Conclusions
Cement task force
Energy Audits
Identification of best practices – cogeneration of
electricity from waste heat
Increased promotion of blended cements
Effective utilization of above energy efficient
materials will enhance the economical growth of
our country.

34. CECRI is there
Not for the PRODUCTION of bridges
But for the PROTECTION of bridges
Not for the inspection of BARS in hotels
But for the inspection of REBARS in bridges
Not for the DISINTEGRATION of materials
But for the INTEGRATION of National Assets
Not for the DOWNFALL of structures
But for the UPLIFTMENT of economy

35. When we build, let us think that
We build for ever
Let it not be, for the present delight
Nor for the present use aloneNor for the present use alone
Let it be such work as our
descendants will thank us for