| 摘要 |
PROBLEM TO BE SOLVED: To measure concentration of strong acid in a mixed acid solution containing hydrofluoric acid being used for pickling descaling of a metallic material and removing surface deposit and containing ions of Fe or Ti or both and strong acid with a larger dissociation constant than hydrofluoric acid. SOLUTION: In this electric potential difference measurement, when Fe is contained, a mixed acid solution as a test solution and a mixed solution of acetylacetone and an organic solvent for dilution are prepared and base is dropped onto it. If necessary, acetyleacetone with 50 times of entire Fe moles is added, an organic solvent with permittivity of 21.0-30.0 is used for dilution, and ethanol is used for dilution. In this electric potential difference measurement, when Ti is contained, a mixed solution is prepared by diluting a mixed acid solution as a test solution with methanol or ethanol containing water of 5-30% and base is dropped onto it. If necessary, a solution mixed with an organic solvent is prepared after hydrogen peroxide is added and mixed with a mixed acid solution as a test solution. COPYRIGHT: (C)2004,JPO
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