초록 ▼

The process will recover sulfuric acid on the 90-95% concentration range by roasting of ferrous sulfate hydrate crystals at high temperature under retort conditions. In the first step of the recovery process 6 (see FIG. 1) hydroxide slurry is reacted with the waste stream, and ferrous sulfate crysta

The process will recover sulfuric acid on the 90-95% concentration range by roasting of ferrous sulfate hydrate crystals at high temperature under retort conditions. In the first step of the recovery process 6 (see FIG. 1) hydroxide slurry is reacted with the waste stream, and ferrous sulfate crystals obtained. In the second step 9 iron sulfate crystals are roasted and water of hydration reacts with sulfate and sulfur trioxide to produce sulfuric acid in a retort operation. The sulfuric acid and sulfur trioxide are condensed or absorbed in water or dilute sulfuric acid and are of a high purity, leaving iron oxide as a recovered carrier. In the third step, this iron oxide/hydroxide is reduced 13 and used to produce a slurry, which is pumped back to react with the entering sulfuric acid waste stream. The process has the following advantages:

대표청구항 ▼

[ What is claimed is:] [1.] A pollution control process for recycling a sulfuric acid waste stream comprising the steps of:a. forming an iron oxide/hydroxide slurry and reacting said slurry with said sulfuric acid waste stream to neutralize acid values and to form ferrous sulfate crystals;b. separat

[ What is claimed is:] [1.] A pollution control process for recycling a sulfuric acid waste stream comprising the steps of:a. forming an iron oxide/hydroxide slurry and reacting said slurry 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 approximately 550 degrees Celsius to 750 degrees Celsius to produce sulfuric acid or sulfur trioxide, ferric oxide and sulfur dioxide;d. separating the sulfuric acid, sulfur trioxide and sulfur dioxide from the ferric oxide leaving a ferric oxide as a residue, said ferric oxide being recovered;e. separating the sulfur dioxide from the sulfuric acid and sulfur trioxide;f. reducing said ferric oxide to ferrous iron using the sulfur dioxide separated in step (e);g. wherein said recycle of sulfur dioxide both reduces said ferric oxide and provides a substantially pure sulfuric acid; andh. recycling said ferrous iron for reaction in step (a).