Upgrading the glassy slag from waste disposal by thermal plasma treatment

The glassy slag is then adopted as a raw material in the production of porous materials intended for various architectural applications, thus eliminating the necessity for its further disposal. The formation of a porous glass-ceramic matrix, using the vitrified slag containing CaSO4 as the pore-forming agent, is described in detail. A glass-ceramic foam with 66% porosity is formed by the rapid heating of the mixture of glassy slag and a 1 wt% of CaSO4, consisting of crystallised calcium aluminosilicate (Ca2Al2SiO7, Ca0.88Al1.77Si2.23O8). The thermal conductivity of the prepared porous material, measured by a laser flash thermal analysis, is 0.22 W·m−1·K−1.