鉄鋼中の微量ホウ素の抽出光度定量法

抄録

The micro-amount of boron in iron and steel was determined rapidly by a solvent extraction method. The sample was dissolved with sulfuric acid and hydrogen-peroxide in a soft-glass test tube. After boiling out the excess hydrogen peroxide by gentle heating, the solution was filtered through filter paper into a polyethylen separating funnel. Hydrofluoric acid was added and then allowed to stand for an hour at room temperature. Then methylene blue solution was added, the solution was extracted with dichloroethane, and the soluble boron was determined by measuring the absorbance of organic layer at 660 mμ against dichloroethane. The residue on the filter paper was ashed and fused with anhydrous sodium carbonate in a platinum crucible. The content was dissolved with sulfuric acid,transfered into a polyethlene separating funnel, and spectrophotometric determination of insoluble boron was carried out with the same procedure as in the case of the soluble boron after addition of hydrofluoric acid. Other common constituents contained in iron and steel did not interfere. The time required for this method was two hours.