Preparation of vanadium tailings based geopolymer by Mechano −alkali activation

In response to the increasing output and low utilization rate of stone−coal vanadium tailings, this experiment focused on vanadium tailings as the main material, activated the vanadium tailings first, and then mixed the activated tailings, metakaolin, and aluminate cement evenly according to the specific ratios, added a certain amount of alkali activator, stirred and mixed the mixed samples thoroughly, and then added standard sand to form mortar. The mortar was injected into a mold with dimensions of Φ40 mm × 40 mm × 160 mm, formed under curing conditions of 101.325 kPa air pressure, and then placed in an environment of 60 °C and 95% humidity for accelerated curing until the specified ages (3 days, 7 days, 28 days). In this experiment, the effects of mechanical activation, vanadium tailings incorporation and alkali excitation on the properties of vanadium tailings base polymers were investigated under the condition of fixing the amount of aluminum corrector (40% aluminate cement and 15% metakaolin) and the water−solid ratio (mass ratio)of 0.36. The study investigated the effects of mechanical activation, the proportion of vanadium tailings, and alkali activation on the properties of geopolymers derived from vanadium tailings. The results showed that the highest flexural and compressive strengths of 4.98 MPa and 32.1 MPa were obtained when the vanadium tailings were mechanically activated for 120 minutes, with a proportion of 45% vanadium tailings, 40% alumina cement, 15% metakaolin, a water−to−solid ratio (mass ratio) of 0.36, a cement−to−sand ratio (mass ratio) of 5, and an alkali activator consisting of NaOH (3%) and Na₂SiO₃ (3%). Microscopic characterization of the prepared geopolymer samples, such as XRD and SEM, revealed the formation of amorphous phase N−A−S−H gellable substance, indicating that vanadium tailings can be successfully used to prepare geopolymers with good properties, providing a new approach for the comprehensive utilization of vanadium tailings.