Proposition of geopolymers obtained through the acid activation of iron ore tailings with phosphoric acid

This study aims to develop a geopolymer using iron ore tailings (IOT) as a geopolymer precursor and phosphoric acid (H3PO4) as an activating agent. IOT was characterized according to Brazilian technical standards, milled and burned at 600 °C. The specimens were cured at 60 °C and 80 °C, undergoing physical, mechanical, and microstructural characterization. Specimens cured at 60 °C have higher density and compressive strength; and can be applied in bricks, precast panels, and in the manufacture of sidewalks. The interaction of an acid and IOT formed crystalline phases containing PO4, responsible for the resistance gain. So far, no research adopts IOT and H3PO4 to develop geopolymers.