3D Printing Geopolymers Recycled from Coal Byproducts

Fly ash from coal

Research into 3D printing consistently yields new methods and materials for additive manufacturing to make use of. Among the most exciting recent material advances was produced by a research team from Nanyang Technological University in Singapore. By experimenting with fly ash, a byproduct of coal combustion, scientists at NTU were able to produce a 3D printable geopolymer that is strong enough to be used in construction.


The process pioneered by the NTU team, though revolutionary in its ability to convert fly ash into a usable material, is actually fairly simple. The fly ash is combined with potassium hydroxide and potassium silicate, making a cement-like material. This mixture can set and cure at room temperature, a fact which allows it to be used in 3D printing. With the correct loading direction, this geopolymer actually proved to be stronger than traditional cement.


Much of the two years that the research team spent on the project was dedicated to optimizing techniques that would allow the new geopolymer to be used in a 3D printer. Though the material readily lends itself to additive manufacturing, the scientists at NTU still had to determine the proper flow rate for printing and make adjustments for the time it takes the geopolymer to set.


The ability to turn fly ash into a functional construction material has immense potential when it comes to reducing the carbon footprint of the construction industry. Though it isn’t hazardous, fly ash is an incredibly common waste material for which few uses have been found up to now. Each year, some 112 million tons of fly ash is produced by India, the world’s leading coal-burning country, with another 100 million tons produced by China and 75 million by the United States. In tandem with 3D printing’s ability to reduce material waste, this type of recycling can make the future of construction as an industry much greener.


This is just one of the many ways in which new research into 3D printing is expanding the potential of the technology to revolutionize the ways in which everything from consumer products to buildings are created. Owing to the wide range of different uses that 3D printing will have in the manufacturing and building processes of the future, it’s important that today’s students are introduced to it at a young age. Me3D’s classroom 3D printers are an excellent choice for getting students started with 3D printing and helping them explore the vast potentials of the next generation of manufacturing technology.