Analytical Sciences

Determination of Silicon in High-Silicon Electrical Steel by ICP-AES with On-line Sample Electrolytic Dissolution

Michihiro AIMOTO,* Hiroyuki KONDO,* and Akihiro ONO**

*Advanced Technology Research Laboratories, Nippon Steel Corp., 20-1 Shintomi, Futtsu, Chiba 293-8511, Japan
**The Japan Society for Analytical Chemistry, Gotanda Sanhaitsu No. 305, 1-26-2 Nishi-gotanda, Shinagawa, Tokyo 141-0031, Japan

A flow-injection procedure combining electrolytic sample decomposition and inductively coupled plasma atomic emission spectrometry (ICP-AES) is proposed in order to rapidly determine the content of silicon in high-silicon electrical steel. This system is characterized by sample decomposition through electrolysis directly coupled to ICP-AES. A steel sample is dissolved by electrolysis using a 6 mol L^-1 HCl solution as an electrolyte with a flow rate of 5 mL min^-1; the electrolyte containing a dissolved sample is subsequently introduced into ICP-AES via a nebulizer. The effects of the electrolysis current and the temperature on the decomposition of the sample were studied. Samples were electrolyzed under the condition of a 1.5 A constant current, at room temperature (25°C) to avoid the hydrolysis of silicon to precipitate. Comparing the analytical results of steel samples obtained by this analytical system with those obtained by the gravimetric method, determined values agreed well quantitatively. The RSD of silicon at approximately 3% was 0.3% (n = 6).

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