Systems and methods to treat flue gas desulfurization and metal-bearing waste streams to recover value-added materials

A method for processing a waste stream, the method comprising:

• configuring a processor to operate a process comprising:
• loading a first powder feedstock into a first reactor, wherein the first powder feedstock comprises a calcium sulfate component;
• introducing an ammonium carbonate reagent to the first reactor to produce ammonium sulfate and calcium carbonate in a reaction slurry;
• pumping the reaction slurry to a second reactor when a reaction to produce ammonium sulfate and calcium carbonate is complete thereby forming a reacted slurry;
• filtering the reacted slurry resulting in a calcium carbonate residue and ammonium sulfate filtrate liquor;
• loading a second powder feedstock into a third reactor, wherein the second powder feedstock comprises a metal-bearing component, a silica component, and an aluminosilicate component;
• leaching the second powder feedstock by at least one of contacting, passing, and percolating an acid and hydrogen peroxide through the second powder feedstock and collecting a metal-bearing leachate formed in the third reactor, wherein after collecting the metal bearing leachate, the third reactor comprises dried solids comprising silicates;
• responsive to collecting the metal-bearing leachate, adjusting a pH value of the metal-bearing leachate to a first predetermined pH value to precipitate a first component from the metal-bearing leachate, wherein the first predetermined pH value is 4, and wherein the first component comprises iron and aluminum;
• responsive to precipitating the first component, separating by filtration the first component, and collecting a first filtrate in a fourth reactor;
• and
• responsive to collecting the first filtrate, adjusting the first filtrate to a second predetermined pH value to precipitate a second component from the first filtrate, separating by filtration the second component to result in a second filtrate, and collecting the second filtrate in a fifth reactor.