| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for treating a waste acid, with which corrosion of equipment on the downstream side of a roasting furnace caused by gaseous hydrochloric acid produced in the roasting furnace is prevented while suppressing increase in the cost of equipment.SOLUTION: A method for treating a waste acid: which includes a waste acid spraying step to conduct a roasting reaction by spraying the inside of a roasting furnace with a waste hydrochloric acid solution, and a water spraying step to spray the inside of the roasting furnace with water after the waste acid spraying step and before extinction of the roasting furnace; and in which temperature of a surface in contact with exhaust gas on the downstream side of the roasting furnace is kept at 140°C or more by controlling temperature of the exhaust gas from the roasting furnace in the water spraying step; or which includes, in addition to the mentioned respective steps, a waste-heat recovery step to recover thermal energy from the exhaust gas by using a heat exchanger installed on the downstream side of the roasting furnace in the waste acid spraying step and in the water spraying step; and in which temperature of a surface of the outlet side of the heat exchanger is kept at 140°C or more by controlling the temperature of the exhaust gas from the roasting furnace in the water spraying step; is provided. |
