Abstract
A rapid method of determination of a small amount of carbon (less than 0.05%) in steel has been developed, in which carbon is absorbed in barium hydroxide as carbon dioxide and excess barium is titrated with EDTA.
The carbon dioxide produced by combustion of the sample is absorbed in a barium hydroxide solution in 0.1N sodium hydroxide, to which is added a definite amount of alcohol to assure the complete precipitation by reducing the solubility of barium carbonate. The excess of barium ion in the solution retaining the precipitate is titrated with a standard solution of EDTA using Eriochrome Black T as an indicator and the amount of carbon is calculated. While the conventional method based on the acid-base titration is usually accompanied with a certain difficulty in the complete recovery of carbon dioxide owing to the limited concentration of the alkali, the proposed method by EDTA chelate titration has effectuated the rapid and simple absorption of carbon dioxide by increasing the alkalinity of absorbing solution and by introducing a porous glass absorption tube. The time required for an analysis of the steel sample was about 13min. and D4(2)R was 0.0028%.
