ESTIMATION OF BORON IN FERRO-ALLOYS USING ICP-OES BY MICRO-WAVE DIGESTION

In order to produce high grade plated steel sheets to be consumed at the automobile industry, blast furnace mills requires to ferro-alloys containing low boron. However, the content of boron differs largely depending on the sources to produce ore as raw material. Nowadays, the boron analysis in these ferro alloys are being carried out in our organization using the ICP-OES technique because of its wide elemental coverage, very low detection limit, fast analysis time, wide analytical working range (ppb to wt%), simple spectra of the constituents elements and high matrix tolerance. The solid sample is first digested in acid medium inside a sealed PTFE Micro-wave Digester vessel in order to avoid any chance of loss of boron.  After the solution is made at 800 W power using a high pressure of 40 K Bar, it is being analyzed using the ICP-OES. The axial mode of the wavelength 249.772 has been selected for the corresponding boron analysis in each case in order to remove any possible interference from any other elements present in the matrix. Fig.1 shows the calibration curves made for doing the analysis whereas Fig.2 shows the corresponding emission spectra of the B 249.772 analyte for a standard silico-manganese sample (SL01-04) along with unknown silico manganese, ferro manganese and Ferrochrome samples.

Boron

Till today, boron has been estimated for several ferro alloy samples using the above established method in ICP. In each case, the standard Silico manganese samples (SL01-04 and SL01-03) whose B content are known have been compared with the actual measurement of the standard using the above calibration curve. Table 1 shows the results of boron content for some of the ferro alloy samples determined using the above method. The good compatibility between the results declared for the standard sample with that obtained by the above method, and very low standard deviation during measurement justifies the precession and accuracy of the established method.

Boron Table

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