| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method by which calcium ions and sulfuric ions can be recovered as solid components, and the chloride of alkali metal such as sodium chloride having a low content of impurities can be recovered without using chemicals such as sodium carbonate and barium chloride when a filtrate after the removal of heavy metals from slurry such as flying ash is treated. <P>SOLUTION: The method of recovering chloride comprises a first stage (A) wherein the temperature of a filtrate comprising calcium ions, alkali metal ions, sulfuric ions and chloride ions is controlled to≥50°C, and after stirring, solid-liquid separation is performed to obtain solid components comprising gypsum and liquid components comprising alkali metal ions and chloride ions; and a second stage (B) wherein the temperature of the liquid components obtained in the first stage is controlled to≤80°C (however, lower than the temperature controlled in the first stage), and after stirring, solid-liquid separation is performed to obtain solid components comprising the chloride of alkali metal and liquid components. <P>COPYRIGHT: (C)2004,JPO</p> |
