Construction of layered double hydroxide composites derived from tungsten tailing particles for simultaneously enhancing fire protection and anti-ageing properties of intumescent fire-resistant coatings applied in wood surface

Tungsten tailing is a great deal of solid waste produced in the production process of tungsten metal, for which there is no simple and effective treatment method in the world. The success synthesis of layered double hydroxide composites (TTF-LDH) by co-precipitation method from tungsten tailing is a feasible way to solve this problem. The structure and properties of TTF-LDH were confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The obtained TTF-LDH was in combination with intumescent flame retardants (IFR) to achieve a series of intumescent fire resistance coatings. The effects of TTF-LDH on the fire protection, smoke suppression and anti-ageing performances of coatings were evaluated by fire resistance test, smoke density test, cone calorimeter test and accelerated ageing test, while the flame-retardant mechanism of TTF-LDH in coatings was revealed. The results illustrate that an appropriate amount of TTF-LDH can remarkably enhance smoke suppression and fire-resistant abilities of coatings, among which the coating containing 3 wt % TTF-LDH (IFRC-LDH3) exhibits the optimal synergistic effect, revealing a smoke density rating value of 17.3%, a total heat release of 7.0 MJ/m2 and an equilibrium backside temperature of 146.2 °C at 900 s. Meanwhile, the addition of TTF-LDH can strengthen the char formation and thermal stability abilities of the coatings, and the residual weight of IFRC-LDH3 rises to 35.7% at 800 °C, as supported by thermogravimetric (TG) analysis. The results of accelerated ageing test demonstrate that the presence of TTF-LDH can strengthen structural stability of coating, decrease migration and decomposition of IFR, thus giving the coating better integrity and durability of fire-resistant and smoke suppression properties.