Project nominated for the Excellence in sustainability Steelie Award 2020
In October 2019, Gerdau launched the Sustainable House project in Brazil, where the company’s main operations are located, and where 7 million new homes are estimated to be needed to house people in precarious situations.
The project aims to build houses using recycled materials and sustainable technologies. A 45 m² pilot house was built with around 20 tonnes of iron ore tailings and mining co-products, and used sustainable technologies, such as solar and wind power generation, biodigesters (which reuse waste to produce gas and fertiliser), composting tanks, rainwater storage systems and water recycling.
The Engineering Department of the Federal University of Minas Gerais (UFMGa) developed a pioneering technology (called flash calcination) in partnership with Gerdau to make:
- construction blocks that contain 40% tailings from iron ore mining, which give the home thermal and acoustic comfort
- permeable flooring with 60% tailings, which is designed to reduce soil impermeability, helping to reduce impacts from flooding mortar with 60% tailings
- the material was also used to make the countertops in the kitchen and service area
Unprecedented in Brazil, the procedure enables the calcination of microparticles, which can be carried out in conventional ovens. This makes it possible to transform some mineral compounds from raw materials, such as rock waste and tailings, into high-strength ligands.
The Sustainable House shows that investments and technology can transform one of the industry’s biggest challenges into new opportunities for companies, society and the environment. It is a powerful example of developing new applications that are sustainable as well as value-added for mining waste and tailings. As a result, the disposal of these materials in dams and piles is reduced, while reducing the use of natural resources.