| 摘要 |
<P>PROBLEM TO BE SOLVED: To use the forcibly caused variation of a liquid property like pH value as an index of the variation of concentration of dissolved calcium. <P>SOLUTION: When removing dissolved calcium in a treating object liquid by aeration with carbon dioxide, addition of alkali is started or stopped within a given pH range, to forcibly raise or lower pH of the treating object liquid. Lowering time of pH in this operation is checked in a Step 100, aeration with carbon dioxide is appropriately controlled in a Step 200 or a Step 300, to correctly determine stopping. <P>COPYRIGHT: (C)2012,JPO&INPIT |
