Development of a Rapid Determination System for Phosphorus and Sulfur in Iron.

Abstract

In order to determine the contents of phosphorus and sulfur rapidly in the iron-making process, a new determination system has been developed. This system is characterized by the rapid extraction of phosphorus and sulfur from a solid sample by the wet chemical reaction, and simple detection using a paper-tape detector. Hydrochloric acid is sprayed onto the surface of an iron sample, and about 5mg of the sample is dissolved. Phosphorus and sulfur in the sample are extracted as phosphine and hydrogen sulfide, respectively, during the supply of hydrochloric acid. These gases are transferred to a paper-tape detector with an inert-gas carrier. In the detector, phosphine and hydrogen sulfide are reacted with silver nitrate and lead acetate, respectively, on the paper tapes; the resulting stain is measured by reflectance photometry. As the result of analyzing pig iron, ranges of 0.01-0.1% phosphorus and 0.003-0.03% sulfur are determined simultaneously with relative standard deviations of 15% or less. The time required to analyze one sample is less than 2min. This system is expected to be used at production sites of the iron-making process.