CaF_2 沈殿分離-原子吸光分析による低水素用溶接棒被覆剤ならびに同原料中の F の間接定量

概要

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An indirect determination of F by atomic absorption spectrophotometry was studied. F was precipitated as CaF_2, and Ca in CaF_2 which was separated by filtering was determined by atomic absorption analysis. The results are as follows : (1) The addition of excess CaCl_2 as a reagent for precipitation decreased the solubility of CaF_2 in the solution. (2) The solution was boiled for formation of CaF_2, and CeCl_3 was added to the solution, after cooling to room temperature F^- dissolved in the solution was precipitated as CeF_3. (3) When absorbance of Ca^<2+> was measured after HClO_4 dryness of CaF_2 and CeF_3, the presence of Ce^<3+> in CeF_3 increased absorbance of Ca^<2+>. (4) The amount of F, when 20mg or over, recovered by both Ca^<2+> and Ce^<3+> was about 96.5% actually, and the amount of F obtained from the absorbance of Ca^<2+>, which was increased by Ce^<3+>, was indicated twice as much as F (about 1.5%) recovered by Ce^<3+>, but the amount of F recovered as CaF_2 was about 95%, and as CeF_3 was about 1.5%. These values were nearly constant so that the effect of the increase of the absorbance was used in that condition for increase of value of F, and F could be determined as the recovery of about 98%. (5) The method was successfully applied to the determination of F in the coating of the low hydrogen type of electrode, fluorides of alkaline earth metals, and cryolite.
社団法人日本鉄鋼協会の論文
1975-03-01