PURIFICATION AND ESTIMATION OF RAW-MATERIALS FOR FLUORIDE OPTICAL FIBER

Zirconium fluoride and barium hydrogen fluoride were purified by diethyldithiocarbamate extraction and sublimation. Purity of the materials was estimated by NAA for transition elements and by charged particle activation analysis for oxygen. The impurity concentrations in purified zirconium fluoride were 2.6 ng/g iron, 0.018 ng/g for cobalt, 4.6 ng/g for nickel and 1.1 ng/g for copper. Trace amounts of iron and cobalt could be determined in the zirconium fluoride by irradiation for 265 h, followed by chemical separation. The concentrations of iron, cobalt, nickel and copper in the purified barium hydrogen fluoride were 17 ng/g, 0.044 ng/g, 1.41 ng/g and 0.2 ng/g, respectively. Trace amounts of nickel were determined using the Ni-58(n,p)Co-58 nuclear reaction. The analytical results for the transition elements in the prepared zirconium and barium hydrogen fluorides show that solvent extraction and sublimation are the best methods for the preparation of high-purity raw materials for fluoride optical fiber.