Geopolymers are changing the world

Concrete can be substituted with geopolymers, which are manufactured from industry waste or side products. Geopolymers are also suitable for binding hazardous chemical waste, or, for example, as construction material for playgrounds.

Main image: A more porous geopolymer can be used for insulant matter, among other things. Composition of the matter can be regulated by altering the manufacturing conditions.

 

The Fibre and Particle Engineering research group in the University of Oulu do groundbraking research in spurring on bio- and circular economy.  They aim to find ways to utilize industrial waste, and simultaneously decrease the stress that industry causes to the environment. Their newest research subject is geopolymers.

Geopolymer is a concrete-like substance. It is produced, for example, in the steel and mining industry from waste material high in silicon and aluminum in certain alkaline ie. high pH conditions. The composition of the substance can be regulated by changing the conditions.

 

Professor Mirja Illikainen believes that factory production of geopolymer to substitute for concrete can be demonstrated on a large scale in the near future. This new construction material that utilizes the gigantic waste flows of industry could be on the market in five to ten years.

 

Geopolymer forming this way could be used, among other things, to substitute for concrete. Geopolymer endures very high temperatures, and it can therefore be used in catalyst support structures and in fireplaces and ovens. A more porous geopolymer is can be used as insulant matter.

The substance can also be used for stabilizing harmful chemicals, and in water purification. With the use of moulds, geopolymer can be cast into almost anything, from folders to noise barriers.

”I believe that geopolymers will change the world”, says Professor Mirja Illikainen from the University of Oulu. “With this method we can even process large by-product flows from industry, and in addition, we can still discover many new small application opportunities.”

Manufacture of geopolymer strains nature as much as 80 per cent less than manufacture of concrete

Geopolymer technology has existed for a long time - some claim that even the Egyptian pyramids were made by casting geopolymer. The term was coined by a French researcher in the 1970’s. The substance is being commercially utilized at least in Australia.

”Right now geopolymers are a rising field of research”, says Illikainen. The first research project in the University of Oulu started in 2012. Researchers in Oulu focus on finding out if geopolymer could substitute concrete.

”We are hoping to get an EU project where we demonstrate large-scale factory production of a substance to substitute concrete. If our project application is accepted, this new construction material could then be launched in perhaps five or ten years.”

Concrete manufactured with geopolymer technology is also competitive cost-wise against traditional concrete.

The University of Oulu studies and develops many application opportunities for geopolymers. In addition to studying concrete, researchers in Oulu look into how geopolymer could be used in stabilizing heavy metals, in processing concentrated sands produced in the mining industry, and in the manufacture of insulator materials.

”In addition, we have small research projects run by international exchange students. One of them is looking into the applicability of geopolymer in 3D printing.”

”We are doing research from the angle of the Finnish industry in order to discover advisable uses for industrial waste”

There are approximately 30 researchers working in the Fibre and Particle Engineering research unit in the University of Oulu, of which one third works on geopolymers.

”Even though we are still much in the early stages of our research, we have good networks”, says Illikainen. Geopolymers are studied in collaboration with, for example, universities in Italy, Poland, Portugal, England and the Netherlands. Illikainen praises his Italian colleagues as the best in the world in applying geopolymers in the binding of heavy metals.

”Our specialty is the use of ashes produced by fluidized bed combustion as building material for geopolymer. Another of our specialities is research of insulant wool waste produced by the construction industry.”

”We are doing research from the angle of the Finnish industry in order to discover advisable uses for industrial waste. In addition, we have one Academy project, which allows us to go deeper in understanding geopolymer structure.”

 

Steel and mining industry waste material containing silicon and aluminum can be processed into very durable geopolymer, which can be cast in any kind of shape, into bars, or even into a 3D print.

 

Researchers in Oulu started the Tekes-funded Geodesign project together with the University of Lapland at the start of this year. The goal of the project is to find a way to utilize industrial waste by using geopolymer material, and to strengthen the positive attitude that Finns already have towards recycling. At the same time, the project aims to find meaningful and aesthetically beautiful uses for geopolymers manufactured from waste, such as environmental art.

The project is funded by the mineral wool manufacturer Paroc Group, the metal industry company Boliden Harjavalta, the glass wool manufacturer Saint-Gobain Rakennustuotteet, the energy company Fortum Power, and the waste incineration impurities processing Suomen Erityisjäte. Another company involved in the project is Destaclean, which utilizes construction waste in its production.

The Challenge Finland project is utilized in seeking new companies to use geopolymer in their production.

Circular economy is about large-scale recycling and sustainable use of natural resources

The research focus in the Fibre and Particle Engineering unit has moved over the years from mining and paper industry process engineering into bio and circular economy research. This change follows the changing needs of the surrounding society, and it has been speeded up by the renewal of waste tax in 2011.

In addition to geopolymers, the research unit is developing new and valuable biomaterials and biochemicals from wood and cellulose. Utilizing waste and side products is at center stage in this field of research as well.

“Circular economy is forcefully promoted through both legislature and incentives: 650 million euros have been allocated from the European Union Horizon 2020 program for themes of circular economy. By utilizing by-product flows of industry, we can decrease the use of our limited natural resources and hold back climate change. This is important so that new generations could share the good living conditions we are now enjoying.”

 

Text: Raija Tuominen
Pictures: Joel Karppanen and the Fibre and Particle Engineering research unit

 

Last updated: 8.9.2016