Cement

Cement is a binding agent and is a key ingredient of the most used man-made material: concrete. The demand for cement is strongly correlated to the rate of economic development. Cement manufacturing is the third largest energy consuming and CO2 emitting sector, with an estimated 1.9 Gt of CO2 emissions from thermal energy consumption and production processes in 2006.1 If Best Available Technologies can be adopted in all cement plants, global energy intensity can be reduced by 1.1 GJ/t-cement, from its current average value of 3.5 GJ/t-cement. This would result in CO2 savings of around 119 Mt.2

Dry, semi-dry, semi-wet and wet processes are the four main process routes that are used for the production of cement. Dry processes are considerably more energy efficient but the choice of technology mainly depends on the state of raw materials.  Thanks to the availability of dry materials a great share of production in the developed world is today converted to dry processes. Dry processes are also the choice for new plants or for those looking for expansions or upgrades. The energy-intensive wet process is still used in some countries (and is a considerable share of production in the Former Soviet Union, Australia, and New Zealand), but is being phased out in many countries.

Most of the energy use and CO2 emissions of the cement industry is linked to the production of clinker, which is the main component of cement and produced by sintering limestone and clay. Electricity needed for crushing and grinding raw materials, fuel, and the finished products represents another important energy demand.  Proven technical options with potential to enable considerable reductions in energy use and CO2 emissions can be categorized into: use of energy efficient technologies; use of alternative raw materials and fuels, and reducing the clinker content of cement via increased use of other blends.  There are also emerging options in the form of alternative cementitious materials and carbon capture and storage.   

CementSchematic

Raw material preperation alternative-raw-materials Automated process control Mechanical Transport System Gravity type blending silos High Efficiency Classifiers Clinker Making Addition of Mineralizers Heat Recovery for Power Generation Kiln Shell heat reduction combustion system improvements Energy Management and Process control Low Pressure Drop Cyclones Additon of Precalciner Clinker Cooling Optimized Heat Recovery Fuel Preperation High Efficiency Mills for Fuel Grinding High Efficiency Classifiers for Fuel Grinding Use of Alternative fuels Finish Grinding VRM for Finish Grinding High Efficiency Classifiers Process Control in Finish Grinding Grinding Aids in Ball Mills Blended Cement Alternatives Improved Grinding Media in Ball Mills Optimizing Fuel Properties VSDs for Cooler Fans Low and Negative Carbon Cement Alternatives Carbon Capture and Storage Cement Plant General Measures Preventative Maintenance High Efficiency Motors and drives Variable Speed Drives

Cement Publications

Energy Efficiency Improvement Opportunities for the Cement Industry

The U.S. Environmental Protection Agency’s (EPA) energy guide, Energy Efficiency Improvement and Cost Saving Opportunities for Cement Making, discusses energy efficiency practices and technologies that can be implemented in cement manufacturing plants. This ENERGY STAR guide provides current real world examples of cement plants saving energy and reducing cost and carbon dioxide emissions.

Development of State of the Art Techniques in Cement Manufacturing: Trying to Look Ahead

The report represents the independent research efforts of the European Cement Research Academy (ECRA) to identify, describe and evaluate technologies which may contribute to increase energy efficiency and to reduce greenhouse gas emissions from global cement production today as well as in the medium and long-term future. 

Energy Efficiency and Resource Saving Technologies in Cement Industry

 

This Cement technologies booklet was compiled by the APP Cement Task Force (CTF) through one of its activities to help its member countries share information on all available energy efficient technologies generally used in the world’s cement industry. The document offers a comprehensive compilation of commercially-available energy efficient technologies used in the cement industry.

International Best Practices for Pre- Processing and Co-Processing Municipal Solid Waste and Sewage Sludge in the Cement Industry

This report describes international best practices for pre-processing and co-processing of municipal solid waste and sewage sludge in cement plants, for the benefit of countries that wish to develop co-processing capacity. The report is divided into three main sections, concentrating on: a) fundamentals of co-processing; b) examples of international regulatory and institutional frameworks for co-processing, and; c) international best practices related to the technological aspects of co-processing.

Cement Tools

Cement Manufacturing Energy Performance Indicator Tool

US Flag Developed by the United States Environmental Protection Agency, the ENERGY STAR Cement Plant Energy Performance Indicator (EPI) is a statistical model that allows cement manufacturing plants located in the US to benchmark their energy performance against the industry. Annual plant energy and operating data is entered into the model to receive an energy efficiency score on a scale of 1 to 100.

Sewage Sludge Use in Cement Companies as an Energy Source (SUCCESS) Tool

Chinese Flag This Excel-based tool serves to assist decision makers in implementing sludge-end-use-in-cement schemes with optimal economic and environmental outcomes. The environmental and economic costs and benefits associated with burning sewage sludge in cement kilns will vary based on the energy content of the sludge (lower heating value) and the transportation distance between the wastewater treatment plant and proposed cement plant.

Depending on the employed production technology, characteristics of raw materials, and the composition of final products cement manufacturing can show significant variations in energy consumption and CO2 emissions. In the following, best attainable values for different production processes and for different cement products are presented.

CementBenchmarks

International Benchmarks for Thermal Energy Consumption in Clinker Making with Different Technologies1
Production Process Energy Consumption (GJ/t Clinker)
Min Max
Dry, multistage cyclone pre-heater and pre-calciner kilns 2.85 3.0
Dry process rotary kilns with cyclone pre-heaters 3.1 4.2
Semi-dry/semi-wet processes (Lepol kiln) 3.3 4.5
Dry process long kilns   5.0
Wet process long kilns 5.0 6.0
Shaft kilns (up to 100 t/d capacity) 3.1 4.2

World Best Practice Final Energy Intensity Values for Portland Cement2
Process Energy carrier Product unit kWh/t product GJ/t prduct kWh/t clinker GJ/t clinker kWh/t cement GJ/t cement
Raw materials preparation Electricity t raw meal 12.05 0.04 21.3 0.08 20.3 0.07
Solid fuels preparation Electricity t coal 10 0.04 0.97   0.92  
Clinker making Fuel t clinker       2.85   2.71
  Electricity t clinker     22.5 0.08 21.4 0.08
Additives preparation Fuel t additive            
  Electricity t additive            
Finish grinding                
325 cement Electricity t cement         16 0.06
425 cement Electricity t cement         17.3 0.06
525 cement Electricity t cement         19.2 0.07
625 cement Electricity t cement         19.8 0.07
Total                
325 cement             59 2.92
425 cement             60 2.92
525 cement             62 2.93
625 cement             62 2.93
Assumptions: Ratio of "t of raw materials per t of clinker "is 1.77; ratio of "t of coal per ton of clinker" is 0.97;  clinker to cement ratio in Portland cement is 0.95; additives to cement ratio in Portland cement is 0.05. 

 

World Best Practice Final Energy Intensity Values for Fly Ash Cement2
Process Energy carrier Product unit kWh/t product GJ/t prduct kWh/t clinker GJ/t clinker kWh/t cement GJ/t cement
Raw materials preparation Electricity t raw meal 12.05 0.04 21.3 0.08 13.9 0.05
Solid fuels preparation Electricity t coal 10 0.04 0.97   0.92  
Clinker making Fuel t clinker       2.85   1.9
  Electricity t clinker     22.5 0.08 14.6 0.05
Additives preparation Fuel t additive            
  Electricity t additive         7 0.03
Finish grinding                
325 cement Electricity t cement         23 0.08
425 cement Electricity t cement         25 0.09
525 cement Electricity t cement         28 0.10
625 cement Electricity t cement         28 0.10
Total                
325 cement             52 2.04
425 cement             54 2.05
525 cement             57 2.06
625 cement             na na
Assumptions: Ratio of "t of raw materials per t of clinker "is 1.77; ratio of "t of coal per ton of clinker" is 0.97;  clinker to cement ratio in fly ash cement is 0.65; additives to cement ratio in fly ash cement is 0.35 (5% gypsum, 30% fly ash). 

 

World Best Practice Final Energy Intensity Values for Blast Furnace Slag Cement2
Process Energy carrier Product unit kWh/t product GJ/t prduct kWh/t clinker GJ/t clinker kWh/t cement GJ/t cement
Raw materials preparation Electricity t raw meal 12.05 0.04 21.33 0.08 7.5 0.03
Solid fuels preparation Electricity t coal 10 0.04 0.97   0.34  
Clinker making Fuel t clinker       2.85   1.0
  Electricity t clinker     22.5 0.08 7.9 0.03
Additives preparation Fuel t additive            
  Electricity t additive         25 0.09
Finish grinding                
325 cement Electricity t cement         41 0.15
425 cement Electricity t cement         44 0.16
525 cement Electricity t cement         49 0.18
625 cement Electricity t cement         51 0.18
Total                
325 cement             57 1.65
425 cement             60 1.66
525 cement             65 1.68
625 cement             na na
Assumptions: Ratio of "t of raw materials per t of clinker "is 1.77; ratio of "t of coal per ton of clinker" is 0.97;  clinker to cement ratio in blast furnace slag cement is 0.35; additives to cement ratio in blast furnace slag cement is 0.65 (5% gypsum or anhydrites, 60% fly ash). 

Footnotes

Benchmark Footnotes: 

[1]

EU-China Energy and Environment Programme (2009) Cement - A reference guide for the industry.

[2]

Worrell, E., Price, L., Neelis, M., Galitsky, C., Nan, Z. (2008) "World Best Practice Energy Intensity Values for Selected Industrial Sectors", Lawrence Berkeley National Laboratory. p.24 (Available here)

Globally, more than 3.3 billion tons of cement was produced in 2010.  Graphs below show the global distribution of production and the shares of top 10 cement producing nations. 

Globally, the cement sector is dominated by a small number of large companies.  Largest cement companies, and their capacities and sales are also provided below.

Cement production is an energy intensive process, with energy costs representing 20-40% of production costs (IEA, 2007. p. 145).

Since 1990s, globally there has been a gradual reduction in the "clinker ratio" – the ratio of clinker to cement in the final product – which reflects in reduced specific energy consumption. China is believed to have the lowest clinker ratio in 2010, due to extensive use of granulated blast furnace slag, fly-ash, boiler bottom-ash and a variety of other substitutes.

The table below provides an overview of the availability of materials that can be used as clinker substitutes and their current consumption levels.

Current Use and Availability of Clinker Substitutes (IEA, 2007. p150)
Clinker Substitute Use in 2004 (Mt) Availability (Mt)
Total blast furnace slag n.a. 180 – 220
Granulated blast furnace slag 90 110
Fly ash 222 445
Pozzolona  50 n.a

 

General Industry Characteristics

Global Cement Consumption

See Source Data

2011 [1]

Name Million tons
2006 2568
2007 2763
2008 2830
2009 2998
2010 3294
TOTAL 14453
Back to Chart

2011 [1]

Global Cement Consumption by Region in 2010

See Source Data

2010 [2]

Name %
North Asia 60
South Asia 5
Australasia 0.5
North America 3
South America 3
Central America 0.5
Western Europe 7
Eastern Europe 3
Central Europe 1
North & West Africa 4
Central & South Africa 1
Indian Sub-continent 8
Middle East 5
TOTAL 101
Back to Chart

2010 [2]

Top ten cement producing nations in 2010

See Source Data

2010 [3]

Name Mt
China 1868
India 216
USA 65
Turkey 62
Iran 61
Brazil 58
Vietnam 55
Japan 54
Russia 50
Egypt 48
TOTAL 2537
Back to Chart

2010 [3]

Capacities of leading cement companies

See Source Data

2010 [4]

Name Mt
Lafarge 199
Holcim 212
HeidelbergCement 112
Cemex 97
Italcementi 81
TOTAL 701
Back to Chart

2010 [4]

Cement sales of leading companies (2010)

See Source Data

2010 [5]

Name Mt
Lafarge 141
Holcim 137
Heidelberg Cement 78
Cemex 66
Italcementi 54
Buzzi Unicem 27
TOTAL 503
Back to Chart

2010 [5]

Footnotes

There are numerous organizations working at global, regional, national levels with improving the resource productivity and reducing the environmental impact of cement manufactuing. Some of the major ones are listed below:
Original research for this section is performed by Lawrence Berkeley National Laboratory's China Energy Group.

Cement Organizations Global

Cement Organizations Asia-Pacific

Cement Organizations Australia

Cement Organizations Brazil

Cement Organizations China

Cement Organizations Europe

Cement Organizations European Union

Cement Organizations India

Cement Organizations United States

Cement Organizations Iran

Cement Organizations Japan

Cement Organizations South Korea

Cement Organizations Turkey

Programs Description: 

There are a number of organizations working at global, regional, national levels with improving the resource productivity and reducing the environmental impact of cement manufacturing. Information on some of the major programs can be found below:

Cement Programs Global

Cement Programs Australia

Cement Programs China

Cement Programs European Union

Cement Programs India

Cement Programs Iran

Cement Programs Japan

Cement Programs Turkey

Cement Programs United States

Industrial energy efficiency can be greatly enhanced by effective management of the energy use of operations and processes. Experience shows that companies and sites with stronger energy management programs gain greater improvements in energy efficiency than those that lack procedures and management practices focused on continuous improvement of energy performance. An Energy Management Systems (EnMS), which is a collection of procedures and practices to ensure the systematic tracking, analysis and planning of energy use in industry, provides such a framework to manage energy and promote continuous improvement. They establish assessment, planning, and evaluation procedures which are critical for actually realizing and sustaining the potential energy efficiency gains of new technologies or operational changes.

There are a number of guidelines aimed at helping companies to establish an effective EnMS - including those from United States Environmental Protection Agency (US EPA) and the recent ISO 50000 series of the International Standards Organization.

Although they may differ in their details, these guidelines promote continuous improvement of energy efficiency through: 

  • Organizational practices and policies;
  • Team development;
  • Planning and evaluation;
  • Tracking and measurement;
  • Communication and employee engagement; and;
  • Evaluation and corrective measures (US EPA, 2010)

While EnMSs can help organizations achieve greater savings through a focus on continuous improvement, they do not guarantee energy savings or carbon dioxide reductions alone. Combined with effective plant energy benchmarking and appropriate plant improvements, EnMSs can help achieve greater savings. 

[1]

International Energy Agency (2009) Energy Technology Transitions for Industry.  p. 78

[2]

International Energy Agency (2012) Tracking Clean Energy Progress. p.34