| 摘要 |
PURPOSE:To enable the freezing point to be furthermore lowered by adding more than two kinds of various additives effective in lowering the freezing point into strong phosphoric acid. CONSTITUTION:A mixed substance composed of at least more than two kinds of compounds which are selected out of phosphoric acid, non-conjugated non- organic salt, acid different in kind with proton conductivity and non-ionic substances, are added to strong phosphoric acid. This permits the freezing point to be furthermore lowered than the case when each compound is independently added to said acid. This constitution can prevent freezing even when operations are suspended under a low temperature environment. In this case, the non-ionic substances to be used shall, if desirable, be alcohol fluoride. strong phosphoric acid to be used shall be, if desirable, usually in the amount of 80 to 105% in terms of ortho phosphoric acid. Furthermore, the additive amount of the mixed substance shall, if desirable, be less than 60% strong phorphoric acid by weight. |
