Coming up with solutions and new sustainable products for the construction industry by turning waste into new materials
The cement industry within the framework of the circular economy
How does the cement industry fit into the circular economy?
1. Increasing the efficiency of the resources by recycling
For decades, the cement sector has been one of the great recyclers of the economy where the volume of waste coming from other industrial activities used in the manufacture of its products is concerned. Examples of this practice include fly ash, slag, construction and demolition waste, sludge from paper or sugar manufacturing processes, etc.
2. Developing comprehensive solutions for waste reutilisation: responsible use of the resources
The cement industry acts responsibly, invariably seeking different ways to mitigate the environmental impact of its operations. To reduce this impact we turn waste into alternative and more environmentally-friendly fuels for our manufacturing plants, complying with the current environmental legislation, and with all the safety guarantees.
By using alternative fuels we are reducing our fossil fuel consumption, ensuring that the waste does not go to the dump and cutting down on our CO2 emissions.
This saving on the use of fossil fuels is equivalent to the annual energy consumption in over 500.000 homes.
“In 2015, the cement industry used more than 763,000 tonnes of recovered fuels, which is tantamount to over 361,000 tonnes of petroleum, 21.5% of the energy consumed by the clinker furnaces”.
What does co-processing mean?
It is the use of waste either as raw materials or an energy source, or both, instead of using natural mineral resources (recycled material) and fossil fuels (energy valorisation), when that waste would otherwise have to be disposed of at a disposal site.
Co-processing offers a safe and sound solution for society, the environment and the cement industry, replacing non-renewable resources with waste that is subjected to strict control measures.
Waste as fuels
Some waste can be used at cement plants to replace the coke from oil or coal (non-renewable fossil fuels) that is generally utilised in these facilities. We are thus using the energy contained in an infinite resource, such as waste, instead of using a fuel derived from petroleum, which is a finite resource that tends to run out. This process is known by a variety of names, depending on whether it is from a legal or a technical perspective: “energy valorisation”, “co-incineration” or “energy recovery”.
It must also be pointed out that we are referring to waste that it has not been possible to reuse or recycle and that is currently being dumped at disposal sites.
Advantages of using waste at cement plants
Valorisation at cement manufacturing plants:
- It is no longer necessary to dump waste at disposal sites with the negative impact associated with this practice. That is to say, dumped waste releases methane on fermenting, and it is a “greenhouse effect” gas that pollutes 20 times more than CO2.
- It provides society with an additional tool for managing its waste, and reduces the investment needed, because it utilises existing facilities, such as cement plants.
- It recovers the energy contained in the waste that cannot be reused or recycled and that would otherwise end up at the disposal site.
- It reduces the emissions of greenhouse-effect gases by replacing fossil fuels with materials that would otherwise have been incinerated or dumped as landfill. Furthermore, some waste can be used to replace the limestone needed to manufacture cement and thus prevent the release of the CO2 that is produced in the lime decarbonation process.
- It cuts down on the use of raw materials because it replaces some of those materials that are required to manufacture cement, utilising instead waste with similar characteristics in its composition.
- It reduces the consumption of fossil fuels because it takes advantage of the calorific value of the waste and no longer uses other fossil fuels and finite fuels. It makes the cement industry more competitive by cutting down on manufacturing costs. Energy costs amount to an average of 40% of the total costs.
- It is a suitable environmental treatment guarantee because the combustion takes place at very high temperatures, which guarantees the destruction of the organic compounds in the waste.
- No waste is generated at the end of the valorisation process. Co-incineration or valorisation does not generate slag or ash, because these are permanently or irreversibly incorporated into the clinker (the intermediate material needed to manufacture cement), while conserving the environmental and product quality guarantees.
Health and Safety Guarantees
The recovered waste is subjected to all the health and safety analyses required, in the same way as this is done with traditional fossil fuels, natural raw materials and other components. These tests are conducted with suitable procedures that include personnel prevention and protection equipment and specific storage facilities that are safer for each material.
Scientific evidence is overwhelming and shows, without any doubt, that the use of fuels prepared from waste does not increase emissions from the plants, and neither does it cause any further risks to personal health and safety, while at the same time guaranteeing the same quality for the product.