Determination of calcium,magnesium,aluminium, iron and manganese in wollastonite by inductively coupled plasma atomic emission spectrometry

The content of five elements in wollastonite, including calcium, magnesium, aluminum, iron and manganese, was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) with Ca 317.933 nm, Mg 285.213 nm, Al 396.153 nm, Fe 238.204 nm and Mn 257.610 nm as analytical lines under the following experimental conditions: power of 1.2 kW, plasma cooling gas flow rate of 15 L/min, auxiliary gas flow rate of 0.2 L/min, atomizing gas flow rate of 0.8 L/min and sample uptake amount of 1.5 mL/min. The dissolution of sample was discussed. The results showed that some samples could not be directly dissolved in acid. Therefore, two sample treatment methods, direct acid dissolution and acid dissolution-alkali fusion, were proposed. When the sample was directly dissolved by hydrochloric acid, nitric acid and hydrofluoric acid, the matrix effect had no influence on the determination of Ca, Mg, Al, Fe and Mn. The matrix effect existed when the sample was treated by acid dissolution-alkali fusion. However, it could be eliminated by matrix matching method. In order to improve the precision and accuracy of the determination of high content Ca in wollastonite, the yttrium was used as internal standard. The proposed method was applied to the determination of standard and actual wollastonite samples, and the results were consistent with the certified values and those obtained by wet method. The relative standard deviations (RSD, n=8) were less than 2.5 %.