| 摘要 |
The present invention relates to a method for preparing poly-ferric sulfate in order to treat sewage by using a waste sulfuric acid generated in a semiconductor process. The method can prevent environmental pollution by recycling the waste sulfuric acid and iron oxide disposed of as byproducts of the process, reduce the amount of residual heavy metals, and obtain high-purity poly-ferric sulfate. According to the present invention, the method includes: a ferric sulfate preparing step of mixing the sulfuric acid and iron oxide disposed of as byproducts of the process in a first reaction tank (10) at a temperature of 80-110°C for one to three hours to prepare ferric sulfate (ST 1); a solution mixing step of mixing the prepared ferric sulfate with a solution of NaFeO_2 and Na_2CO_3 by using a high-speed emulsifier (ST 2); and a heat polymerization step of aging the mixture mixed in the previous step in a second heat polymerization tank (30) at a temperature of 30-80°C for one to four hours (ST 3). |
