Abstract: The invention discloses a method of making waterproof magnesium oxychloride refractory brick using fly ash from municipal solid waste incineration (MSWFA). The solidification and stabilization of heavy metals in MSWFA is achieved by the chemical action of a sulfur-containing compound and a physical wrapping of a geopolymer. The large amount of chloride ions in MSWFA is also reused in the manufacture of magnesium oxychloride refractory brick, which requires a high chlorine environment. This method, with the inclusion of the geopolymer, also produces refractory brick exhibiting improved water resistance relative to traditional magnesium oxychloride refractory brick, thereby allowing the improved magnesium oxychloride refractory brick to be used in a wider range of applications.

Abstract: The invention discloses a method of making waterproof magnesium oxychloride refractory brick by fly ash from municipal solid waste incineration. The method comprises the following steps: (1) sulfur-containing compound and water are mixed into the fly ash and stirred evenly to make stabilized slurry, the heavy metals are stabilized and CaO is turned to Ca(OH)2 during this process. (2) The aqueous solution of MgO and MgCl2 is added into the stabilized slurry to make magnesium oxychloride slurry by being stirred evenly. (3) The magnesium oxychloride slurry is cured to make magnesium oxychloride gel, (4) and the magnesium oxychloride aggregate is prepared by crushing the magnesium oxychloride gel. (5) The blended slurry is prepared by mixing metastable material, alkali metal hydroxide, Na2SiO3, magnesium oxychloride aggregate and water, (6) after being stirred, molded and cured, the waterproof magnesium oxychloride refractory brick is obtained.