PROCESS

Iron Oxide production begins when waste acid is pumped to a venturi scrubber where it is concentrated by hot gases from the spray roaster. The concentrated waste acid undergoes the following chemical reaction:

4FeCl₂ + 4H₂O + O₂ → 2Fe₂O₃ + 8HCl
Iron Oxide is discharged from the bottom of the spray roaster while the hot HCl gases leave from the top.

The hot HCl gases pass through the venturi scrubber, and flow to the absorber. HCl is then absorbed preferentially in recirculated water from the scrubber to produce recycled hydrochloric acid. Exhaust gases are scrubbed before being discharged to the stack by the exhaust fan.

Normally, 1 - 1.5 pounds of iron oxide are produced from each gallon of waste acid processed. Iron oxide is produced in the form of hollow spherical granules, which when crushed, have sub-micron range primary particles.