Vanadium-bearing shale tailing is a type of solid waste with high silicon content. Due to high storage capacity, high production capacity, and low utilization rate, Vanadium-bearing shale tailing needs to be thoroughly studied to achieve resource utilization. [1] Alkali activated two-part geopolymer is a new type of inorganic polymer material made from aluminosilicate minerals. Due to environmental-friendly, excellent mechanical properties, and advantages in immobilizing heavy metals, geopolymer is the most promising inorganic polymer material to replace traditional Portland cement. [2] However, two-part geopolymer synthetic raw materials include two parts: alkali activator solution and active aluminosilicate powder. [3] The potential safety risks and operational difficulties of high concentration and high alkalinity alkaline corrosive activator solutions may limit the application of geopolymer. Therefore, researchers propose using solid alkali activators to prepare one-part geopolymer. [4] The chemical composition of Vanadium-bearing shale tailing indicates that it is suitable for synthesizing silicate based solid alkali activator.

There has been extensive research on the preparation of alkali activators from industrial solid waste, and the preparation methods can be mainly divided into three categories: fusion, hydrothermal, and thermochemical. [5] This study used thermochemical method to treat Vanadium-bearing shale tailing to prepare solid alkali activator. Then, the solid alkaline activator activates the metakaolin to synthesize one-part geopolymer.

XRD, Raman, and pH tests were used to analyze the significant effects of reaction temperature and sodium hydroxide dosage on the phase composition and activation effect of solid alkali activators. When the thermochemical activation temperature are 1073.15 K ~ 1273.15 K, the ratio of sodium hydroxide to Vanadium-bearing shale tailing are 90% ~ 100%, and the ratio of solid alkali activator to metakaolin are 66.7% ~ 100%, the compressive strength of one-part geopolymer is above 40 MPa. The main silicate phases of solid alkali activators are sodium silicate. XRD, SEM-EDS, Raman and NMR analyses indicate that sodium silicate mainly plays a role in alkali activation, and sodium silicate can be used as one-part geopolymer silicate raw material. 

The one-part geopolymer synthesized by alkali activator from Vanadium-bearing shale tailing has excellent compressive performance. Solid alkali activator can replace commercial sodium silicate as a cost-effective and environmental-friendly to prepare one-part geopolymer.