| 摘要 |
PROBLEM TO BE SOLVED: To provide a waste liquid treating method which is capable of easily and efficiency taking out a component 1, such as sodium sulfate and a component 2, such as sodium formate, from the waste liquid generated in a manufacturing process step for printed circuit boards, etc. SOLUTION: The treating method of the waste liquid discharged from the manufacturing process step consists in heating the waste liquid essentially consisting of the component 1 which is constant in the solubility in water even if its temperature is elevated and the component 2 which is higher in the solubility in the water than the component 1 and is raised in the solubility in the water with an increase in the temperature to a high temperature to evaporate the moisture in the waste liquid, thereby first taking out the crystal above the saturated solubility in the component 1 attaining the saturated solubility as the crystal by a filtering means, then cooling the component 2 included in the waste liquid before attaining the saturated solubility at the heating temperature and taking out the crystallized component 2 attaining the saturated solubility at the cooling temperature as the crystal by the filtering means. |
