PROCESSES FOR TREATING FLY ASHES

摘要

There are provided processes for treating fly ash. For example, the processes can comprise leaching fly ash with HCl so as to obtain a leachate comprising aluminum ions and a solid, and separating the solid from the leachate; reacting the leachate with HCl so as to obtain a liquid and a precipitate comprising the aluminum ions in the form of AlCl3, and separating the precipitate from the liquid; and heating the precipitate under conditions effective for converting AlCl3 into Al2O3 and optionally recovering gaseous HCl so-produced.

主权项

1. A process for treating raw fly ash, said process comprising:
optionally a pre-leaching treatment that consists of reducing the particle size of said raw fly ash; leaching said raw fly ash with HCl under conditions effective to obtain a leachate comprising aluminum ions and iron ions and a solid, and separating said solid from said leachate; reacting said leachate with HCl so as to increase concentration of HCl in said leachate under conditions effective to decrease solubility of AlCl3 and to substantially selectively precipitate aluminum ions, thereby obtaining a liquid comprising iron ions and a precipitate comprising said aluminum ions in the form of AlCl3, and separating said precipitate from said liquid; and heating said precipitate under conditions effective for converting AlCl3 into Al2O3 and optionally recovering gaseous HCl so-produced.