Research Of Determination For Boron Sulphur And Phosphorus

Determination of boron,sulphur and phosphorus in steel was investigated.Determination of Boron in steel by spectrometric method was used.In a media of formic acid-sodium format buffer solution of pH 3.6,borax,phenylhydroxyacetic acid and[Fe(phen)₃]²⁺form a hydrophobic associate extractable with 1,2-dichloroethane.The content of boron in steel samples is determined by determining that of iron in the organic phase by a UV-spectrophotometer.This method demonstrates satisfactory selectivity for boron.A system of 4.0 mL 1,2 -dichloroethane was applied to extraction for shaking 5 min and laying 10min.The detecting was not affected by excessive phenylhydroxyacetic acid, ammonium iron sulfate and 1.10-phenanthroline.The dynamic calibration curve was obtained under the range of 0.07～3.2μg/mL,the equation of calibration curve was A=0.301c-0.007 and the correlative coefficient was 0.9988.The detection limit is 0.03μg/mL and has the advantages of simple operation,good selectivity and low detection limit to determine boron in steel,an excellent agreement between the analytical results and certified values were found with a relative standard deviation between 1.0%and 6.3%.A new method with microwave decomposing sample and active alumina adsorption column separation was established,then race sulphur was detected by ion chromatogram.Steel sample was dissolved by aqua regia and decomposed by microwave,so the sulfur translated into sulfate ion.The deco-mposed liquid was flowed through adsorption column and sulfate ion was separated with other metal ions,detected by ion chromatogram after sulfate anion was washed away.Under optimizing working condition of microwave digestion,active alumina adsorption column and ion chromatogram,the following results for the new method were obtained,the dynamic calibration curve was obtained under the range of 0.02-150μg/mL,the equation of calib -ration curve was G=1.32c -0.08 and the correlative coefficient was 0.9992.The detection limit was 0.014μg/mL.the new method has more advantages than national standard method. However,a large amount of bromine water,high chloric acid can be avoided to use,so reduced the pollution of the environment and the danger of operation,etc. It is suitable for the determination of large quantities of samples.The method showed a satisfactory result when certified steel samples were determined. With the advantages of simple operation,good selectivity and low detection limit, this method shows a potential application to determine trace amount sulphur in steel.The relative standard deviation of samples was in the range of 1.4%～2.8%.Union nature of the heteropoly acid may be extracted by the polar organic reagent and the indirect flame atom absorption.Determination of trace of phos -phorus in steel by the Flame Atom Absorbance SpectropHotometry(FAAS) was investigated.After the steel sample digestion,phosphorus is converted to pposphate.Then,poospoate reacts with molybdic acid producing phosphormol ybdate complex extractable by methyl isobutyl ketone.Phosphorus is determined in a quantitative relationship with the molybdenum in the complex when molybdenum is detected by FAAS.A system of 5.0 mL methyl isobutyl ketone was appolied to extraction for shaking 3 min and laying 10 min.The dynamic calibration curve equation was A=0.0419c+0.0007 and the correlative coefficient was 0.9973 within the range of 0.04～1.00μg/mL of phosphorus.The detection limit was 0.015μg/mL,The method showed a satisfactory result when certified steel samples were determined with 0.7%～10%of RSD.With the advantages of simple operation,good selectivity and low detection limit,this method shows a potential application to determine trace amount phosphorus in steel.