The concept of a circular economy is growing in influence and as a result the cement production process has begun to evolve. As a large-scale cement producer, Turkey shows considerable potential for the adoption of this alternative economy.
Turkey has begun to adopt the concept of a circular economy, a waste-to-energy solution that is a high priority for European Union. The circular economy model is based on the principle that natural resources are finite and aims to protect the environment as well as reduce waste production.
A circular economy is an alternative to the linear economy, which is based upon the idea of ‘Take, Make and Dispose’, through which a huge amount of waste is produced. However, in a circular economy the cycle involves a step that converts waste back into a usable resource (see Figure 1), thereby greatly reducing waste.
The circular economy system relies on industrial symbiosis. Taking place in the last step of the circular economy cycle, the idea is that certain industries can work together to convert waste back into a raw material through co-processing. For example, fly ash from thermal power plants is commonly used as an alternative raw material in the cement manufacturing process.
Circular economy principles in cement production
Cement production is a unique process with regards to the recycling and recovery operations that take place within it. There are several ways in which the cement sector actively applies the principles of a circular economy.
Energy can be recovered from waste products and used as an alternative fuel in clinker production. Through the process of industrial symbiosis, wastes from other industries such as municipal waste and dried urban wastewater treatment sludge can be used as alternative fuels in the manufacturing process, replacing conventional fuels such as coal and petcoke.
The cement industry is also adapted for a circular economy through the application of alternative raw materials and clinker substitution. For instance, clinker can be easily replaced with materials generated as by-products of other industries such as fly ash from thermal power plants and blastfurnace slag. Waste streams that contain both calorific value and mineral value, such as end-of-life tyres, are ideally suited to co-processing.
The final stage of the circular economy of cement is its application in the production of concrete (see Figure 2). Providing it is of substantial quality and free of contaminants, concrete can be fully recycled. Once concrete has reached the end of its life it can be used as aggregate in subsequent concrete manufacture, completing a cycle of production.
Turkish potential
As set out by the Turkish Cement Manufacturers’ Association in its report ‘The role of the Turkish cement sector in circular economy’ (2017), Turkey has a considerable potential for alternative fuel usage. The country produces 28Mta of municipal waste which is enough to produce 7Mta of fuel. The Turkish cement sector has the capability to use 7Mta of solid waste-derived fuel, which could save the industry almost 3Mta of coal or solid fuel as well as 1.7Mta (seven per cent) of CO2 emissions. Energy recovery from waste would lead to a smaller landfill footprint and lower the volume of methane gas emitted from such sites.
In 2016, 19.5Mt of waste was generated in the country’s thermal power plants of which only 12,000t was hazardous, according to figures by the Turkish Statistical Institute. Ash and slag made up 87.8 per cent of the waste. A significant portion of the total waste, 83.3 per cent, was disposed of in ash disposal areas or controlled landfill sites. Only 16.7 per cent of the total was sent to licensed waste treatment facilities and mines or quarries. These figures highlight the significant potential for substitution of primary raw materials in cement production.
EU comparison
On average, Turkey uses one per cent (1.16Mt) of alternative raw material in cement manufacturing, in comparison to an average of 3.52 per cent (6.75Mt) across the EU.
The EU uses 41 per cent of alternative fuels to supply the thermal energy required during cement production. However, Turkey has a thermal substitution rate of just 3.86 per cent, amounting to 0.62Mt of fossil waste and biomass, which is considerably lower than the EU average.
Main action areas for Turkish cement industry
Turkey is a large-scale cement producer, with an output of 77Mt in 2016. Therefore, it has a significant potential to adopt the concept of a circular economy. To address the low thermal substitution rates, the country has begun to acknowledge that legislative action is necessary to meet the standards of other nations such as the EU member states.
To create an effective circular economy within Turkey, certain action areas need to be addressed. The waste management and recycling systems need to undergo legislative revisions and regularly hit recycling targets. Large-scale industrial symbiosis is needed, with industrial sectors regularly reusing the waste products of others. A revision of the amount of raw materials needed to create a particular product is required as well as an extension of product durability. Finally, energy efficiency and material consumption at the production and utilisation stage needs to be improved.
Major players in the Turkish cement industry intend to achieve these targets by increasing the use of alternative fuels and clinker substitution. In its 2014-15 sustainability report, Akçansa reported a clinker factor of 88.3 per cent in 2015. However, the company plans to reduce this to 79 per cent by 2020. Akçansa also expects to substitute 29 per cent of fuel with waste products by 2020. Çimsa, another subsidiary of the Sabanci Group, recorded an alternative fuel use of 8.67 per cent in 2016. On a positive note, across the Turkish cement industry, secondary fuel use rose by 567 per cent in 2015.
Furthermore, where a sufficient supply is available, the average secondary fuel substitution rate is 20 per cent.
Conclusion
The Turkish cement sector aims to achieve its potential to successfully implement the principles of the circular economy in its production facilities. The recovery of energy, industrial by-products and municipal and other wastes will be key. In addition, the sector plans to develop its cooperation with stakeholders, raise awareness and produce solutions.
References
1 European Commission (2017), ‘Circular Economy’ at: http://ec.europa.eu/environment/circular-economy/index_en.htm
2 Ellen MacArthur Foundation (2017), ‘Circular Economy Overview’ at: https://www.ellenmacarthurfoundation.org/circular-economy/overview/concept
3 European Commission, Circular Economy package – what’s in it? Pierre Henry DG Environment, Unit “Eco-innovation and Circular Economy”, at: http://ec.europa.eu/environment/circular-economy/pdf/seminar/1%20DG%20ENV_Circular%20Economy%20package.pdf
4 CEMBUREAU (2016), ‘Cement, Concrete and the Circular Economy’ at: https://cembureau.eu/media/1229/9062_cembureau_cementconcretecirculareconomy_coprocessing_2016-09-01-04.pdf
5 WBCSD-CSI ‘Getting the Numbers Right’(GNR) at: http://www.wbcsdcement.org/index.php/key-issues/climate-protection/gnr-database
6 Turkish Cement Manufacturers’ Association (2015), Renewable Energy General Directorate Cement Sector Energy Benchmark Study.
7 Turkish Cement Manufacturers’ Association (2017), The role of the Turkish cement sector in circular economy’.
8 CEMBUREAU Statistics
9 ECOFYS (2016), ‘Market opportunities for use of alternative fuels in cement plants across the EU’ at: https://www.ecofys.com/files/files/ecofys-2016-
10 Turkish Statistical Institute (2016), ‘Thermal Power Plants Water, Wastewater and Waste Statistics’, at: http://www.turkstat.gov.tr/PreHaberBultenleri
This article was first published in International Cement Review in February 2018.
