Synthesis of High-Purity Copper(II) Fluoride Dihydrate for Carrier-Distillation Emission Spectroscopy

Abstract

The preparation and analysis of high-purity copper fluoride dihydrate for use as a carrier in emission spectroscopy is described. Copper metal was oxidized with hydrogen peroxide or nitric acid in the presence of an excess of different grades of hydrofluoric acid. The resulting copper fluoride was analyzed to determine the effect of different factors on the levels of impurities. The quality of the hydrofluoric acid was the main factor affecting the purity of the product. The order of appearance of contaminants during crystallization of copper fluoride is described. Iron, nickel, and manganese gradually appear as the mother liquor is concentrated, while silicon, tin, aluminum, and lead usually contaminate only the lots immediately preceding evaporation of the solution to dryness. Magnesium, regardless of its concentration in the mother liquor, coprecipitates with all lots of copper fluoride.