Comparative study for determination of nitrogen in ferrovanadium and ferrotitanitum

Abstract

For the determination of nitrogen in ferrovanadium and ferrotitanium, a vacuum fusion method, two inert gas fusion methods and a modified Kjeldahl method were compared. The effect of Pt, Pt-Ce, Ni and Ni-Ce as bath metal was investigated for vacuum fusion and inert gas fusion methods, and best results were obtained for nitrogen when the ratio of bath metal to sample was 45 in inert gas fusion method with the Pt bath. Kjeldahl method was a modified JIS method involving 40 ml sulfuric acid (1+4) as solvent {Bunseki Kagaku, 19, 1278 (1970)}. In ferrovanadium analysis the highest value of nitrogen was obtained by inert gas fusion method with heat and extraction time for 30 s (Leco TC-36) when platinum was used as a bath metal (A). The determination values of nitrogen with vacuum fusion method with Pt-Ce bath using graphite capsule and with Kjeldahl method (B) were 10% lower than those by (A). Inert gas fusion result by heat and extraction time for 15 s (Leco TC-30) was lower than other methods. In ferrotitanium analysis, nitrogen values of (A) and (B) were in good agreement while other methods gave inferior results to those. A high fusion temperature for certain time duration and a quick heating-up for sample in inert gas fusion method were inferred to give better nitrogen decomposition and extraction from such samples as ferrovanadium and ferrotitanium.