The effect of alkali concentration on the properties of activated tungsten tailings

The 7d unconfined compressive strength tests of alkali-activated tungsten tailings and the microscopic characteristics tests of scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) were conducted to investigate the effect of alkali-solid ratio on the properties of alkali-activated tungsten tailings. The test results indicate that the unconfined compressive strength of alkali-activated tungsten tailings increased with the alkali-solid ratio. However, the strength decreases slightly when the alkali-solid ratio is 12%. The microstructures of the gels generated in the alkali-activated tungsten tailings are affected by the alkali-solid ratio. The details are as follows: the microstructure is honeycomb in low alkali-solid ratio (7%, 8% and 10%), with N-A-S–H as its primary form, and flocculation in high alkali-solid ratio (14% and 15%), mainly in the form of C-A-S–H. When the alkali-solid ratio is at the medium level (12%), the microstructure is a small round bead, and the N-A-S–H is equivalent to the C-A-S–H. The more C-A-S–H content, the greater the strength. This study can provide a scientific basis and technical reference for the resource utilization of tungsten tailings.