Determination of Cr, Si and P in High-carbon Ferrochromium with Microwave Assisted Digestion of the Sample

Dissolution of high-carbon ferrochromium sample by microwave assisted digestion was proposed. The sample (0.200 0 g, with size<0.076 mm) was dissolved with HClO4 5 mL and HF 1 mL in a microwave digestor, and 5 mL of sat′d solution of boric acid were added to the digested solution, which after diluting to 200 mL was used for determination of the 3 elements. One hundred mL of the solution were taken for determination of chromium by oxidation with ammonium persulfate and potential titration with standard ammonium ferrous sulfate solution. Another aliquot of 50.00 mL was taken for determination of Si and P by ICP-AES. Analytical spectral lines selected for Si and P were 251.612 nm and 213.618 nm respectively. Three standard samples were analyzed by this method, giving results in consistency with the certified values, and values of average RSD′s (n=6) of 0.09% for Cr, 0.49% for Si and 2.2% for P.