Preparation of porous slag-based geopolymer spheres by direct template route for pH buffering applications

Abstract

• Porous spheroidal slag-based geopolymer spheres were fabricated by a facile direct template route. • 100wt% (slag) as the mineral material was used for the porous geopolymer spheres fabrication. • High ratio of the open porosity to the total porosity and high OH − leaching (0.029 mol/dm 3 g) were achieved. • This study proposed a viable high value-added route to upcycling slag. Porous slag-based geopolymer spheres with a high degree of sphericity were produced by a facile direct template route. The porosity, cellular morphology, chemical structure, specific surface area, mechanical properties as well as pH buffering capacity of the obtained spheres was investigated. The obtained slag-based geopolymer spheres with high porosity and high degree of sphericity as well as acceptable strength have potential application as pH regulators.