cement making process and how the energy from the fuel is transferred to the process

8/10/2019 Cement Making Process and How the Energy From the Fuel is Transferred to the Process

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1.0 INTRODUCTION

INTRODUCTION TO INDUSTRIAL PROCESS

Industrial processes are procedures that involve either chemical or

mechanical steps to assist a manufacturer / producer in the manufacture/

production of items; these are usually carried out in large or very large scale.

Industrial processes are the key component of heavy industry. Some

industrial processes make the production of different non-common material(physical substance) very much cheaper in price therefore changing it into a

commodity. It therefore makes the process economically convenient to

manufacture materials on a large scale for the society.

Most industrial processes end in desired output(s)/product(s) and by-

products as many of these are hazardous/ dangerous and are difficult to

handle toxic.

The industrial process that would be discussed in this report iscement

making/ processing.


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1.1 INTRODUCTION TO CEMENT PRODUCTION

HISTORICAL BACKGROUND

The word cement commonly refers to a powdered material which usually

develops strong adhesive qualities when it is combined with water. These

materials are more properly known as hydraulic cements. Gypsum plaster,

common lime, hydraulic limes, natural pozzolana, and Portland cements are

the more common hydraulic cements, with Portland cement being the mostimportant in construction.

The Egyptians were the first to invent cement. Cement was later reinvented

by the Greeks and the Babylonians who made their mortar out of lime.

Later, the Romans manufactured cement from pozzolana, the pozzolana is

an ash found in all of the volcanic areas of Italy, by mixing the ash with lime.

Cement is a fine grey coloured powder which, when mixed with water

always forms a thick paste. When the paste is mixed with sand and gravel

and allowed to dry it is called concrete.

About ninety-nine percent of cement consumed today is the Portland

cement. This name is not a brand name. This name was given to the cement

by Joseph Aspdin of Leeds, England who received a patent for his product in

the year 1824. The concrete made from the cement looked like the colour of

the natural limestone quarried on the Isle of Portland in the English Channel.

The balance of cement consumed today consists of masonry cement, which

consist of fifty percent Portland cement and fifty percent ground lime rock.


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In 1871 The United States manufactured its first cement by David Saylor of

Coplay, Pennsylvania.

Two types of raw materials come together to form cement:

Lime-containing materials, such as limestone, marble, oyster shells, marl,

chalk, etc.

Clay and clay-like materials, such as shale, slag from blast furnaces,

bauxite, iron ore, silica, sand, etc.

It takes approximately 3,400 lbs. of raw materials to make one ton (2,000

lbs.) of Portland cement. The mixture of materials is finely ground in a raw

mill. The product of the raw mix is burned in a rotary kiln at temperatures of

about 4482 degrees Celsius to form clinker. The clinker nodules are then

ground with about 3 % gypsum to produce cement with a fineness typically

of less than 90 micrometres.

PRODUCTION PROCESSES

The production of cement takes place with several steps:

Quarrying of limestone and shale

Dredging the ocean floor for shells

Digging for clay and marl

Grinding

Blending of components

Fine grinding


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BURNING

Burning the blended materials is the key in the process of making cement.

The wet or dry mix is then transferred into the kiln, which is one of thelargest pieces of moving machinery in the industry. It is generally has a

diameter of twelve feet or more and a length of 500 feet or more, made of

steel and lined with firebrick. It revolves on large roller bearings and is

gradually slanted with the intake end higher than the output end.

As the kiln revolves, the materials roll and slide downward for a period of

four hours. In the burning zone, the heat can reach 3,000 degrees

Fahrenheit; the materials become incandescent and there would be change

in colour from purple to violet to orange. Here, the gases are driven from

the raw materials, which actually change the properties of the raw

materials. What emerges is clinker which is round, marble-sized, glass-

hard balls which are harder than the quarried rock. The clinker is then

transferred into a cooler where it is allowed cool for the purpose of storage.

FINISH GRINDING

The cooled clinker is mixed with a small amount of gypsum, this usually

helps to regulate the setting time when the cement is mixed with other

materials and becomes concrete. Here again there are primary and

secondary grinders. The primary grinders leave the clinker, ground to the

fineness of sand, and the secondary grinders leave the clinker ground to the

fineness of flour and is the final product that would be marketed.


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PACKAGING/SHIPPING

The final product is shipped either in bulk (ships, barges, tanker trucks,

railroad cars, etc.) or in strong paper bags which are filled by machine. In the

United States, a bag of Portland cement usually contains 94 pounds of

cement, and a barrel weighs four times that amount, or 376 pounds. In

Canada, a bag weighs 87 1/2 pounds and a barrel weighs 350 pounds.

Masonry cement bags contain only seventy pounds of cement.

When cement is shipped, the shipping documents may include sack

weights. This must be verified by the auditor since only the cement is

taxable. Sack weights are always excluded.

FLOW CHARTS OF MANUFACTURING PROCESS

The following pages contain flowcharts of the manufacturing process of

Portland cement. The first chart represents the process in approximately

ninety percent of the plants currently in operation. The second chart

represents the process being used in approximately ten percent of the

plants currently in operations. However, the second process is the one being

used for virtually all new cement plants.(W.O.S.G, 2005)


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FIG 1.TYPICAL MANUFACTURING PROCESSING FLOW CHART (W.O.S.G,

2005)


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FIG 2.NEWER MANUFACTURING PROCESS FLOW CHART (W.O.S.G, 2005)


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2.0 ENERGY FROM FUEL TRANSFERRED TO STEEL MAKING

There are several forms of energy from the fuel that is been transferred to

the cement making process. One of which will be discussed. This form is;

Blast furnace

2.1 BLAST FURNACE

A blastfurnace is a vertical shaftfurnace which produces liquid metals by

the reaction of a flow ofair introduced under pressure into the bottom of

the furnace with a mixture of metallicore,coke, andflux fed into the

top. Blast-furnaces are also used for the production of pig iron from iron ore

for subsequent processing intosteel and in the processing of lead, copper,

and other metals. By the help of the current of air under pressure rapid

combustion is always maintained. (Blast furnace, 2014)

GROUND-GRANULATED BLAST-FURNACE SLAG (GGBS OR GGBFS)

Ground-granulated blast-furnace slag (GGBS or GGBFS) is gotten by

quenching molten ironslag which is a by-product of iron and steel-making

from theblast furnace in water or steam to form/ produce aglassy,it is this

granular product that is then dried and ground into a fine powder.

2.2 HEAT TRANSFER THROUGH THE BLAST FURNACE

The chemical composition of a slag varies considerably depending on the

composition of the raw materials to be used in the process of cement

production. Silicate and aluminate impurities from theore andcoke are

added in theblast furnace with aflux which helps in the reduction of

viscosity of the slag. In the case of producing pigiron the flux will consist

mostly of a mixture oflimestone andforsterite or in other cases consist of
http://www.britannica.com/EBchecked/topic/222589/furnacehttp://www.britannica.com/EBchecked/topic/10582/airhttp://www.britannica.com/EBchecked/topic/431610/orehttp://www.britannica.com/EBchecked/topic/211548/fluxhttp://www.britannica.com/EBchecked/topic/564627/steelhttp://en.wikipedia.org/wiki/Slaghttp://en.wikipedia.org/wiki/Blast_furnacehttp://en.wikipedia.org/wiki/Glassyhttp://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Coke_(fuel)http://en.wikipedia.org/wiki/Blast_furnacehttp://en.wikipedia.org/wiki/Flux_(metallurgy)http://en.wikipedia.org/wiki/Viscosityhttp://en.wikipedia.org/wiki/Iron_productionhttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Forsteritehttp://en.wikipedia.org/wiki/Forsteritehttp://en.wikipedia.org/wiki/Limestonehttp://en.wikipedia.org/wiki/Iron_productionhttp://en.wikipedia.org/wiki/Viscosityhttp://en.wikipedia.org/wiki/Flux_(metallurgy)http://en.wikipedia.org/wiki/Blast_furnacehttp://en.wikipedia.org/wiki/Coke_(fuel)http://en.wikipedia.org/wiki/Orehttp://en.wikipedia.org/wiki/Glassyhttp://en.wikipedia.org/wiki/Blast_furnacehttp://en.wikipedia.org/wiki/Slaghttp://www.britannica.com/EBchecked/topic/564627/steelhttp://www.britannica.com/EBchecked/topic/211548/fluxhttp://www.britannica.com/EBchecked/topic/431610/orehttp://www.britannica.com/EBchecked/topic/10582/airhttp://www.britannica.com/EBchecked/topic/222589/furnace


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dolomite.In theblast furnace the slag will float on top of theiron and it is

decanted for separation. A process where cooling is slow the slag melts

results in an unreactive crystalline material consisting of an assemblage of

Ca-Al-Mg silicates. To obtain a good slag reactivity or hydraulicity, the slag

melt will need to be cooled rapidly or quenched below 800 C to help

prevent the crystallization ofmerwinite andmelilite.To cool and fragment

the slag a process known as the granulation process can be applied; in this

process the molten slag is subjected to jet streams of water or air under

pressure. Alternatively, in the palletisation process the liquid slag is partially

cooled with water and subsequently projected into the air by a rotating

drum. To obtain a suitable reaction, the obtained fragments are ground to

reach the same fineness asPortland cement.

The main components of blast furnace slag are CaO (30-50%), SiO2(28-38%),

Al2O3(8-24%), and MgO (1-18%). In general increasing the CaO content of the

slag will result in raised slagbasicity and an increase incompressive

strength.The MgO and Al2O3content show the same trend up to

respectively 10-12% and 14%, beyond which no further improvement can be

reached. Several compositional ratios have been used to correlate slag

composition withhydraulic activity;the latter being mostly expressed as the

bindercompressive strength.

The glass content of slags suitable for blending withPortland cement varies

from 90-100% and this also depends on the cooling method and the

temperature at which cooling starts. Theglass structure of the quenched

glass largely depends on the proportions of network-forming elements such

as Si and Al over network-modifiers such as Ca, Mg and to a lesser extent Al.

an Increasing amount of network-modifiers will lead to high degree of

network depolymerization and reactivity.
http://en.wikipedia.org/wiki/Dolomitehttp://en.wikipedia.org/wiki/Blast_furnacehttp://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/w/index.php?title=Merwinite&action=edit&redlink=1http://en.wikipedia.org/wiki/Melilitehttp://en.wikipedia.org/wiki/Portland_cementhttp://en.wikipedia.org/wiki/Basicityhttp://en.wikipedia.org/wiki/Compressive_strengthhttp://en.wikipedia.org/wiki/Compressive_strengthhttp://en.wikipedia.org/wiki/Mineral_hydrationhttp://en.wikipedia.org/wiki/Compressive_strengthhttp://en.wikipedia.org/wiki/Portland_cementhttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Glasshttp://en.wikipedia.org/wiki/Portland_cementhttp://en.wikipedia.org/wiki/Compressive_strengthhttp://en.wikipedia.org/wiki/Mineral_hydrationhttp://en.wikipedia.org/wiki/Compressive_strengthhttp://en.wikipedia.org/wiki/Compressive_strengthhttp://en.wikipedia.org/wiki/Basicityhttp://en.wikipedia.org/wiki/Portland_cementhttp://en.wikipedia.org/wiki/Melilitehttp://en.wikipedia.org/w/index.php?title=Merwinite&action=edit&redlink=1http://en.wikipedia.org/wiki/Ironhttp://en.wikipedia.org/wiki/Blast_furnacehttp://en.wikipedia.org/wiki/Dolomite


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Common crystalline constituents of blast-furnace slags

aremerwinite andmelilite.Other minor components which can form during

progressive crystallization arebelite,

monticellite,rankinite,wollastonite andforsterite.Minor amounts of

reduced sulphur are commonly encountered asoldhamite

TABLE 1.PHYSICAL PROPERTIES OF A BLAST FURNACE SLAG (BLAST

FURNACE SLAG, 2014)
http://en.wikipedia.org/w/index.php?title=Merwinite&action=edit&redlink=1http://en.wikipedia.org/wiki/Melilitehttp://en.wikipedia.org/wiki/Belitehttp://en.wikipedia.org/wiki/Monticellitehttp://en.wikipedia.org/w/index.php?title=Rankinite&action=edit&redlink=1http://en.wikipedia.org/wiki/Wollastonitehttp://en.wikipedia.org/wiki/Forsteritehttp://en.wikipedia.org/wiki/Oldhamitehttp://en.wikipedia.org/wiki/Oldhamitehttp://en.wikipedia.org/wiki/Forsteritehttp://en.wikipedia.org/wiki/Wollastonitehttp://en.wikipedia.org/w/index.php?title=Rankinite&action=edit&redlink=1http://en.wikipedia.org/wiki/Monticellitehttp://en.wikipedia.org/wiki/Belitehttp://en.wikipedia.org/wiki/Melilitehttp://en.wikipedia.org/w/index.php?title=Merwinite&action=edit&redlink=1


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TABLE 2.TYPICAL CHEMICAL PROPERTIES OF A BLAST FURNACE

SLAG (BLAST FURNACE SLAG, 2014)


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FIG 3.PROCESS OF CEMENT MANUFACTURING (CEMENT PRODUCTION, 2009)


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FIG 4.COMPARISON OF PORTLAND CEMENT AND BLAST-FURNACE

SLAG CEMENT (JISF, 2014)


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FIG 5. TOP GAS RECYCLING BLAST FURNACE(GLOBALCCSINSTITUTE, 2014)


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FIG 6. A CEMENT PLANT (CEMENT KILN, 2007)


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FIG 7. A GENERAL ROTARY KILN LAYOUT (CEMENT KILN, 2007)


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FIG 8. A PAIR OF KILNS WITH SATELLITE COOLERS IN ASHAKA, NIGERIA

SYSY (CEMENT KILN, 2007)


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FIG 9. A UNIT OF CEMENT CLINKER GRINDING PLANT (ZENITH, 2014)


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FIG 10. CAPACITY OF CEMENT (CEMENT CAPACITY, 2010)

3.0 THE CEMENT INDUSTRY MARKET

In 2010, the world production of hydraulic cement was 3,300 million tonnes.

The top three manufacturers of cement in 2010 were China with 1,800 India


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with 220 and USA with 63.5 million tonnes respectively, a combined total of

over half the world total by the world's three most populated states.

For the world capacity to produce cement in 2010, the case was the same

with the top three states (China, India, and USA) accounting for a capacity

just under half the world total capacity.

Over 2011 and 2012, global usage continued to increase rising to about

3585Mt in 2011 and 3736Mt in 2012, while the annual growth rates eased to

8.3% and 4.2% respectively.

China, representing a growing share of worlds cement consumption,

continued to be the main engine of global growth. By 2012, Chinese demand

had a record of 2160 Mt, which represented 58% of the worlds consumption.

Annual growth rates, which reached 16% in 2010, appear to have softened,

slowing to 56% over 2011 and 2012, as Chinas economy targeted a more

sustainable growth rate.

Outside of China, worldwide consumption went up by about 4.4% to 1462 Mt

in 2010, 5% to 1535 Mt in 2011, and finally 2.7% to 1576 Mt in 2012.

Iran is now the 3rd largest cement manufacturer in the world and has grown

its output by over 10% from 2008 to 2011. Due to the climbing energy costs in

Pakistan and other major cement-producing countries, Iran is in a unique

position as a trading partner, utilizing its own surplus petroleum to power

clinker plants. Now a top producer in the Middle-East, Iran is further

increasing its dominant position in local and international markets.

The performance in North America and Europe over the 20102012 periods

contrasted strikingly with that of China, as the global financial crisis

developed into a sovereign debt crisis for many countries in this region and

recession. Cement consumption/ usage levels for this region fell by about


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1.9% in 2010 to 445 Mt, recovered by 4.9% in 2011, and then dipped again by

1.1% in 2012.

The performance in the rest of the world, which includes many emerging

economies in Asia, Africa and Latin America and representing some 1020 Mt

cement demand in 2010, was positive and more than counter balanced the

declines in North America and Europe. Annual consumption growth was

recorded at about 7.4% in 2010, moderating to 5.1% and 4.3% in 2011 and 2012,

respectively.

As at year-end 2012, the global cement industry consisted of 5673 cement

production facilities, which included both integrated and grinding, of which

3900 were located in China and 1773 in the rest of the world.

Total cement capacity worldwide was recorded at 5245 Mt in 2012, with

2950 Mt located in China and 2295Mt in the rest of the world (Cement, 2014)

METHODS OF ENERGY EFFICIENCY AND EMISSION REDUCTION IN CEMENT

MAKING.

4.1 ENERGY EFFICIENCY REDUCTION IN CEMENT MAKING


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EFFICIENCY IN CEMENT MAKING

The cost of energy as part of the total production costs in the cement

industry is of great significance, warranting attention for energy efficiencyto improve the bottom line. Historically, energy intensity has dropped,

although more recently energy intensity shows to stability with the gains.

The primary fuels in this sector are Coal and coke currently, supplanting the

dominance of the natural gas in the 1970s. Most recently, there was a slight

increase in the use of waste fuels, including tires. Between 1970 and 1999,

Primary physical energy intensity for cement production went down by

about 1% per year from 7.3 MBtu per short ton to 5.3 MBtu per short ton.

Carbon dioxide intensity due to fuel consumption and raw material

calcination also went down by about 16% from 609 lb. C per ton of cement

(0.31 tC per tonne) to 510 lb. C per ton cement (0.26 tC per tonne).

Despite the historic progress, there is still adequate room for energyefficiency improvement. The relatively high share of wet-process plants (25%

of clinker production in 1999 in the U.S.) suggests the occurrence of a

considerable potential, when measured to other industrialized economies.

Over 40 energy efficient technologies and measures and estimated energy

savings, carbon dioxide savings.

The substantial potential for the energy efficiency improvement exists in the

cement industry and in individual plants. A section of this potential will be

achieved as part of (natural) modernization and expansion of existing

facilities, as well as construction of new plants in some regions. Still, a very

large potential to improve energy management practices still exists.

(Climate vision, 2014)


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RECYCLED CONTENT

Cement is produced by heating common materials typically crushed

limestone, clay, iron ore and sand to temperatures of about 2700F(temperature of molten iron). To achieve these high temperatures it is

required to have large volumes of fuels, mainly coal, petroleum coke and

natural gas, waste materials are usually of high energy value and thus be

used as fuel. Common waste such as spent solvents, printing inks, paint

residues and cleaning fluids often are often pointed out as hazardous

because they are flammable and have high fuel value. These and some other

high energy waste like used motor oil and scrap tyres cannot be disposed of

in landfills. However they can be safely burned to destruction by using them

as fuel in cement kiln while reducing the need to use fossil fuels. The

chemistry of cement making enables the kiln ideal for waste destruction.in

this case, energy is not only recovered but many waste also contain

essential materials used for the production of cement.

The cement industry has greatly grown its use of waste materials to fuel the

cement kiln. It also depends currently on the burning of waste materials to

satisfy about 10% of these energy requirements. Cement plants also burns

many industrial waste like sludge from the petroleum industry and

agricultural waste like almond shells.

Cement manufacturers also include non-hazardous by-products generated

from other industries in the raw ingredients used for the manufacturing of

new cement. By-products like fly-ash which is gotten from the production of

electricity, mill scale from steel making and foundry sand from metal

casting. This practice does not only recycle waste but also helps to reduce


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the amount of raw materials taken from quarries. Cement producers even

re-use cement kiln dust a primary by-product of cement production by

recycling it back to the kiln as an ingredient for new cement. (Concrete

thinker, 2014)

EFFICIENCY TO REDUCE ENVIRONMENTAL IMPACT

Portland cement is produced by heating limestone or chalk with clay in a

rotary kiln to at a high temperature say about 1450C to produce hard

nodules of clinker which are then ground with a little amount of gypsum in a

ball mill. The firing process makes use of significant fuel, usually coal or

petroleum coke. Reduced fuel use is a fundamental objective of the cement

industry. The major environmental concerns of cement manufacture are

outlined in the Table 3.0.

The manufacturers have taken steps to minimise the impacts by:

Reducing primary raw material needs by increasing the use of by-

products from other industries, along with dust suppression measures

and landscaping after quarrying.

Use of waste products as alternative fuels (oil, solvents, and tyres)

along with greater emissions control and investment in more efficient

plant (heat exchangers, pre-heaters, insulation). Reducing cement

clinker by replacing during the grinding process with cementitious

materials from by-products from other industries e.g. pfa, ggbs

Use of grinding aids to reduce clinker milling time and improved

equipment efficiency.


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Overnight deliveries, increased rail use, fuel efficient vehicles,

reduction of empty truck movements by making use of returned

concrete loads instead of dumping on site.

STAGES IN THE CEMENT MAKING

PROCESSMAJOR ENVIRONMENTAL CONCERNS

1) Quarrying and processing raw

material

Scarring of landscape, transport

produces dust and noise

2) Burning raw material to make

cement clinker

Carbon dioxide emission from heating

limestone and burning fuel

Gas emissions, such as nitrogen and

sulphur oxides

High energy use

Dust

3) Grinding clinker Electrical energy

4) Delivery to mixing plant, precast

works, builders merchantsFuel, noise and traffic

TABLE 3.ENVIRONMENTAL CONCERNS OF PRODUCING CEMENT

(CONCRETE, 2014)

RECOMMENDATIONS/CONCLUSIONS


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I recommend a world-wide cement emission regulation because next to

water, concrete is the second most consumed substance on planet earth. I

also would like investors to encourage research that would help in the

processing of green cement; environmentally friendly both in processing

and consuming.

REFERENCES


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W.O.S.G, 2005 retrieved on 19 March, 2014, from

http://www.window.state.tx.us/taxinfo/audit/cement/ch1.htm

Blastfurnace,2014. Encyclopdia Britannica Online. Retrieved 19 March,

2014, from http://www.britannica.com/EBchecked/topic/69019/blast-furnace

JISF, 2014 retrieved 20 March, 2014, from

http://www.jisf.or.jp/en/activity/warm/commit/slag.html

Cement production, 2009, retrieved 20 March, 2014, from

http://www.pavementinteractive.org/article/cement-production/

Blast furnace slag, 2014, retrieved 20 March 2014, from

http://www.alf-cemind.com/cd/AF_and_ARM_waste_slag.htm

Global ccs institute, 2014 retrieved on 23 March 2014, from

http://www.globalccsinstitute.com/publications/global-status-ccs-2012/online/48286

Cement kiln, 2007 retrieved on 23March 2014, from

http://en.wikipedia.org/wiki/cement_kiln
http://www.window.state.tx.us/taxinfo/audit/cement/ch1.htmhttp://www.britannica.com/EBchecked/topic/69019/blast-furnacehttp://www.jisf.or.jp/en/activity/warm/commit/slag.htmlhttp://www.pavementinteractive.org/article/cement-production/http://www.alf-cemind.com/cd/AF_and_ARM_waste_slag.htmhttp://www.globalccsinstitute.com/publications/global-status-ccs-2012/online/48286http://www.globalccsinstitute.com/publications/global-status-ccs-2012/online/48286http://en.wikipedia.org/wiki/Cement_kilnhttp://en.wikipedia.org/wiki/Cement_kilnhttp://www.globalccsinstitute.com/publications/global-status-ccs-2012/online/48286http://www.globalccsinstitute.com/publications/global-status-ccs-2012/online/48286http://www.alf-cemind.com/cd/AF_and_ARM_waste_slag.htmhttp://www.pavementinteractive.org/article/cement-production/http://www.jisf.or.jp/en/activity/warm/commit/slag.htmlhttp://www.britannica.com/EBchecked/topic/69019/blast-furnacehttp://www.window.state.tx.us/taxinfo/audit/cement/ch1.htm


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Zenith, 2014 retrieved on 23 March 2014, from

http://www.zenithcrusher.net/quarry-plant/cement-clinker-grinding-plant-

unit.html

Cement capacity, 2010 retrieved on 23 March 2014, from

http://en.wikipedia.org/wiki/File:Cement_Capacity_2010.png

Cement, 2014 retrieved on 23 March 2014, from

http://en.wikipedia.org/wiki/Cement

Climate vision, 2014 retrieved on 24 March 2014, from

http://www.climatevision.gov/sectors/cement/pdfs/final_lbnl.pdf

Concrete thinker, 2014 retrieved on 24 March 2014, from

http://www.concretethinker.com/solutions/Recycled-Content.aspx

Concrete, 2014 retrieved on 24 March 2014, fromhttp://www.concrete.org.uk/fingertips_nuggets.asp?cmd=display&id=141

UNEP, 2010 retrieved on 24 March 2014, from

http://na.unep.net/geas/getUNEPPageWithArticleIDScript.php?article_id=57
http://www.zenithcrusher.net/quarry-plant/cement-clinker-grinding-plant-unit.htmlhttp://www.zenithcrusher.net/quarry-plant/cement-clinker-grinding-plant-unit.htmlhttp://en.wikipedia.org/wiki/File:Cement_Capacity_2010.pnghttp://en.wikipedia.org/wiki/Cementhttp://www.climatevision.gov/sectors/cement/pdfs/final_lbnl.pdfhttp://www.concretethinker.com/solutions/Recycled-Content.aspxhttp://www.concretethinker.com/solutions/Recycled-Content.aspxhttp://www.climatevision.gov/sectors/cement/pdfs/final_lbnl.pdfhttp://en.wikipedia.org/wiki/Cementhttp://en.wikipedia.org/wiki/File:Cement_Capacity_2010.pnghttp://www.zenithcrusher.net/quarry-plant/cement-clinker-grinding-plant-unit.htmlhttp://www.zenithcrusher.net/quarry-plant/cement-clinker-grinding-plant-unit.html

cement making process and how the energy from the fuel is transferred to the process

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