Scandium in several minerals { (0.0020.3) % Sc} was determined by the fluorometric method. The procedure is as follows : (0.050.1)g of mineral sample is treated with 30 ml of concentrated sulfuric acid for 3 hrs on a sand bath, and the solution is evaporated to dryness. The residue is dissolved in (35)ml of concentrated hydrochloric acid, and the solution is diluted to (7080)ml with water and filtered. Seventy milligrams of Ca²⁺ as a carrier and oxalic acid solution are added and the pH of the solution is adjusted to 2.0. After the solution has stood for ten minutes, the precipitate is centrifuged and decomposed by evaporating with perchloric acid to dryness. The residue is dissolved in 5 ml of 6M HCl. Scandium is separated by extracting at pH 1.6 with 10 ml of 0.2M TTA-benzene followed by backextracting with 10 ml of 1M HCl. The solution is made up to 25 ml, and an aliquot of the solution is taken. Two ml of 0.1% 2, 4-dihydroxybenzaldehyde-semicarbazone solution, 2 ml of 20% ammonium acetate solution are added, and the pH of the solution is adjusted to 6 with hydrochloric acid or ammonia, and the solution was diluted to 25 ml with water. The fluorescence intensity of the solution is measured (λ_excitation360nm, λ_emission 425 nm).
In this procedure, the recovery of scandium was found to be about 95%. Several mineral samples (naegite, allanite, yamaguchilite, lepidomelane, hokutolite) were analyzed.