Study on the process and mechanism of unburned bricks from vanadium tailings

The storage of acid leaching vanadium tailings in Southern Shaanxi is large, and there are hidden problems in safety and environment. In order to promote the utilize of vanadium tailings and reduce its harm to the mine and society, vanadium tailings and cement are used as the main raw materials to prepare unburned bricks. The basic properties and environmental safety of vanadium tailings are analyzed, and the material ratio, types and amounts of additives, water consumption and external pressure in the process of preparing unburned bricks are systematically studied. Furthermore, the formation mechanism of unburned bricks are analyzed by X-ray diffraction and SEM. The results show that the vanadium tailings contain high quartz and gypsum content, and the toxicity leaching and radioactivity meet the requirements of building materials standards, and can be used to prepare unburned bricks. And when the ratio of vanadium tailings and cement is 85∶15, the incorporation amount of triethanolamine is 7.5‰, the water-solid ratio is 15%, and the external pressure is 12.5 MPa, the MU15 grade unburned brick can be prepared. The gypsum in vanadium tailings can promote the hydration of silicate minerals in cement under the excitation of triethanolamine. In the process of forming hydrated calcium silicate and hydrated calcium silicate, the minerals are crosslinked into a dense structure, which ensures the strength of unburned bricks. Using vanadium tailings to prepare unburned bricks has high utilization rate of vanadium tailings, which is an effective way to realize vanadium tailings reduction and bulk utilization.