Sulfuric acid waste recycling by regenerative process

A pollution control process for recycling a sulfuric acid waste stream comprising the steps of:

• a. reacting ferrous hydroxide with said sulfuric acid waste stream to neutralize acid values and to form ferrous sulfate crystals;
• b. separating said ferrous sulfate crystals;
• c. retorting said ferrous sulfate crystals at a temperature ranging from 550 degrees Celsius to 750 degrees Celsius to produce sulfuric acid or sulfur trioxide, iron oxide and sulfur dioxide;
• d. separating the sulfuric acid, sulfur trioxide and sulfur dioxide from the iron oxide leaving an iron oxide as a residue, said iron oxide being recovered;
• e. separating the sulfur dioxide from the sulfuric acid and sulfur trioxide;
• f. reducing said iron oxide to ferrous iron using the sulfur dioxide separated in step (e);
• g. wherein said sulfur dioxide both reduces said iron oxide and provides substantially pure sulfuric acid;
• h. slurrying said iron oxide with ferrous hydroxide to form a iron oxide/hydroxide slurry providing the ferrous hydroxide for step (a) and reacting said slurry with said sulfuric acid waste stream to neutralize acid values and to form ferrous sulfate crystals;
• and
• i. repeating steps (b) through (h).