Abstract: The composition of high-speed iron sphalerite is complex, and there are many interference fac-tors in the determination of low-content indium. The paper made a study of the experimental conditions olthe instrument working conditions , acid medium and its concentration , etc. for the determination of indium content in high iron content sphalerite by flame atomic absorption spectrometry. The research resultsshow that at a wavelength of 303. 94 nm , an air-acetylene flame , a burner slit length of 100 mm , a widthof 0. 4 mm, and a test solution injection volume of 6mL / min , the optimal working conditions of the in-strument are: lamp current 5 A; burner height 7 cm; acetylene flow rate 1.8 ~ 2.0 L / min: air flowrate 6. 0L / min; the best acidic medium for the sample to be tested is nitric acid medium with concen-tration ( V / V)% =10% .

Key words: flame atomic absorption method, high iron content sphalerite, indium, measurement conditions