Concrete is the world's most used building material. It is a strong substance, which is also of great importance in emission reduction bars. In order to reduce emissions, industrial side streams, old car tires and carbon dioxide recovery are needed.
Concrete production accounts for up to seven percent of the world's greenhouse gases, in Finland the share is two and a half percent.
Due to its properties, concrete is widely used not only in the frame structures of houses, but also, for example, in the foundations of buildings and infrastructure, such as bridges. Since concrete cannot be replaced on a large scale with other materials, the solution to reducing emissions must be found in concrete itself.
The good news is that low-carbon work has been done in concrete manufacturing in Finland for a long time. Carbon dioxide emissions have been significantly reduced.
Finnsement has a big responsibility as the only cement manufacturer in the country
Carbon dioxide emissions mainly come from the production of cement, the main raw material of concrete.
Finland's only cement manufacturer, Finnsementi, has cut emissions by, among other things, replacing cement ingredients that cause a lot of carbon dioxide emissions with less emitting ones and by using waste as fuel in the incineration process.
The company has also actively explored the possibilities of capturing and storing the carbon dioxide generated in production using new technology.
Finnsement's director of responsibility Ulla Leveelahten according to the company is already aiming for a reduction of no less than 30 percent of direct carbon dioxide emissions during this decade compared to the level of 2021.
The goal is tough already because more than half of the process's carbon dioxide emissions come from the limestone used as raw material, and there is no technical substitute for limestone.
However, much can be done. Leveelahti names the development of mixed cements as one of the successes.
"We have introduced more environmentally friendly alternatives to the market, which use blast furnace slag and limestone, a side stream of the steel industry, as additives. The carbon dioxide emissions of these cements are clearly lower than those of traditional building cements," Leveelahti says.
The cement kiln is hot with tire grit
Leveelahti emphasizes that the current focus on reducing emissions is primarily on low-carbon fuels.
"The share of fossil fuels in the combustion process can be further reduced by replacing them with bio and recycled fuels. Even energy efficiency can still be improved."
The use of recycled fuels is a continuation of the long history of the cement manufacturing industry as a user of industrial side streams. Today, at Finnsement's production plant, it is possible on the best days to replace up to 90 percent of coal with recycled fuel.
"All recycled fuels for the cement kiln are sorted by place of origin, separately collected, processed, and their uniformity is ensured before they arrive at the cement factory. These wastes are unfit for other reuse", states Leveelahti.
As an example, Leveelahti mentions scrap tires from vehicles, the tire scrap made from them can be used 100% in the cement kiln. No waste is left at all.
Adding recycled fuel has required investment in addition to innovation. Among other things, Finnsement's grate cooler investment in the Parainen production facility reduces carbon dioxide emissions by 40 tons per year.
"Emissions reduction is equivalent to replacing no less than 18 gasoline cars with fully electric cars," Leveelahti explains, using Ilmastopanel's calculator in the calculation.
Emissions are reduced to zero with the help of carbon dioxide recovery
Ulla Leveelahti looks to the future and talks about carbon dioxide capture and storage. Research work is being done on it and the technology is developing, but an exact timetable for the implementation of the solutions cannot be given at this stage.
Next year, the first industrial facility enabling the capture and storage of carbon dioxide will be opened in Norway. The opening of the facility is an important milestone for the entire industry.
According to Leveelahti, there are no technical obstacles to the capture of carbon dioxide in Finland, but the logistical challenges are considerable.
"The carbon dioxide should be transported to the oil and gas fields in the Norwegian Sea. The ship's journey to Norway takes ten days. With current production volumes, it would mean that a ship carrying carbon dioxide would leave Parais approximately every three days."
Leveelahti reminds that the development of technology is already fast and will accelerate in the coming years.
"I believe that the cement industry's goal of being carbon neutral in 2050 is realistic. Not all countries will be at the same point at the same time, but the change will proceed in stages. In the Nordic countries, the goal may already be between 2030 and 2040."
Finnsementti has been actively involved in preparing and updating the emission reduction road map for the construction industry.
Leveelahti chaired the Vähähiilinen construction industry 2035 roadmap working group. He is happy that companies in the construction industry clearly have a genuine desire to cut the industry's emissions - and to do significant environmental work.
Photos: Finncementi