| 摘要 |
PURPOSE:To easily and quickly control the concn. of a rock crystal etching soln. by introducing a specified amt. of the rock crystal etching soln. contg. a desired concn. of a hydrofluoric acid by a pump into a flow cell mounted with a fluoride ion electrode and measuring the concn. of fluorine by an ion meter. CONSTITUTION:For example, 1l pure water is preliminarily put into a beaker 4 and 1ml rock crystal etching soln. contg. 250g/l hydrogen fluoride and 150g/l ammonium fluoride is put into the beaker 4 by a fixed displacement pump 3. After the soln. is stirred, the soln. is introduced by a peristal pump 8 into a flow cell 5. The concn. of the fluorine ions therein is measured with the fluoride ion electrode 6 and 300mg/l is obtd. The rock crystal etching is started by using such rock crystal etching soln. 1l pure water is put into the beaker 4 upon lapse of 3hr and 1ml rock crystal etching soln. is drawn by the pump 3 and is put into the beaker 4. The soln. is introduced by the pump 8 into the flow cell 5 and 250mg/l concn. of fluorine ions is obtd. with the electrode 6. The satisfactory etching is executed in the above-mentioned manner. |
