高倍时时彩

Working across continents, 高倍时时彩 and the University of S茫o Paulo are unlocking the potential of using untreated bauxite residue to transform one of the world鈥檚 most carbon-intensive industries: cement production.

Bauxite residue is a byproduct of alumina refining, comprised of mud, residual caustic soda and, in some cases, a coarse sand fraction. Repurposing this waste in cement manufacturing can significantly reduce the amount of land required to store the material, so we have been researching opportunities for beneficial reuse of the material.

The project with the University of S茫o Paulo is funded by the 高倍时时彩 Foundation and it received a best paper award in October of 2022 at the International Committee for Study of Bauxite, Alumina & Aluminium Conference.

The traditional cement-making process begins by heating clay, limestone and other raw materials in a kiln to create a product known as clinker. This clinker is then combined with gypsum and supplementary cementitious materials (SCM), typically fly ash and/or slag, to produce cement. Finally, to make concrete, cement is mixed with water, sand and aggregate.

鈥淧roducing clinker is what generates the majority of carbon dioxide (CO₂) emissions in the cement industry,鈥� said Lance Myers, 高倍时时彩 research program manager and principal research scientist at our Continuous Improvement Center of Excellence. 鈥淥ur project is examining how we can use bauxite residue to replace the amount of cement, and therefore clinker, that鈥檚 required to produce concrete, reducing CO₂ emissions. What sets our research apart is that we鈥檝e developed a process that doesn鈥檛 require any treatment of the residue beyond adding traditional materials.鈥�

This process of eliminating the need for treatment is key, as these treatments often require heat that generates significant CO₂ emissions.

Our scientists in Australia and Brazil and researchers from the University of S茫o Paulo have developed and tested various blended cement pastes containing untreated bauxite residue. Exposure testing of various small-scale concrete products containing this blended cement confirms that they meet requirements for compressive strength, durability and sodium leaching.

鈥淲e hope to expand our testing to larger-scale items to further demonstrate the viability of concrete containing untreated bauxite residue,鈥� said Rafael Giuliano Pileggi, professor at the Polytechnic School of the University of S茫o Paulo and presenter of the award-winning paper. 鈥淲e believe we can replace up to 50 percent of the clinker in blended cement pastes with bauxite residue when making concrete. This potentially can translate into a significant opportunity for using the residue.鈥�