Determination of calcium oxide and magnesium oxide in converter patching refractory by EDTA titration combined with inductively coupled plasma atomic emission spectrometry
Abstract：The maintenance of feeding side, bottom and steel side of the converter using converter patching refractory could increase the lining life of the converter and reduce the environmental pollution. Wherein MgO content affects the service life of furnace lining, while CaO content affects the accuracy of MgO determination. Therefore, it is necessary to accurately determine the contents of CaO and MgO in converter patching refractory. The sample was first burned in muffle furnace for 10 min, and fused with mixed flux of Na2CO3-H3BO3 (mass ratio of 2∶1) at high temperature. Then it was leached and acidified with diluted hydrochloric acid. The corresponding solution was diluted to the mark to obtain test solution. After 5 mL of triethanolamine (1+1) was added in one part of test solution for masking the interference of Cu2+, Ti(Ⅵ), Al3+ and Fe3+, the total content of CaO and MgO was titrated by EDTA standard titration solution in ammonia buffer solution (pH=10) with acid chromium blue K-naphthol green B as indicator. Another part of solution was transferred into 100 mL volumetric flask and diluted to the mark. Then the content of CaO was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) with Ca 317.933 nm as analytical line. The difference between the two above was the content of MgO. Consequently, a method for determination of CaO and MgO in converter patching refractory by EDTA titration combined with inductively coupled plasma atomic emission spectrometry was established. The contents of CaO and MgO in converter patching refractory samples were determined by the proposed method. The relative standard deviations (RSD, n=6) of determination results were 3.5%-4.2% and 0.22%-0.46%, respectively. The recoveries of CaO were between 98% and 101%. The contents of CaO and MgO in certified reference material of magnesia sample with similar composition to converter patching refractory was determined by the proposed method, and the results were consistent with the standard values.
[1] 高华.转炉维护用耐火材料的应用技术及展望[J].耐火材料,2018,12(6):470-474. GAO Hua.Application technology and prospect of refractories for converter maintenance[J].Refractories,2018,12(6):470-474. [2] 李凌云,张寒,马芳,等.炼钢除尘灰中SiO2、P、CaO、MgO、A12O3联合快速测定[J].山东冶金,2016,38(2):42-44. LI Lingyun,ZHANG Han,MA Fang,et al.Joint rapid determination of SiO2,P,CaO,MgO and Al2O3 in steelmaking dust[J].Shandong Metallurgy,2016,38(2):42-44. [3] 王艳红,张瑞峰.EDTA滴定法测定白云石中氧化钙和氧化镁含量方法的改进[J].有色矿冶,2017,33(2):53-56. WANG Yanhong,ZHANG Ruifeng.Method improvement on the determination of calcium oxide and magnesium oxide in dolomite by EDTA titrimetry[J].Non-Ferrous Mining and Metallurgy,2017,33(2):53-56. [4] 张育新.X射线荧光光谱法测定炉渣中主次成分[J].河北冶金,2016(9):17-20. ZHANG Yuxin.Determintion of primary and secondary composition in slag with X-ray fluorescence spectrometry[J].Hebei Metallurgy,2016(9):17-20. [5] 崔宏利.熔融制样-X射线荧光光谱法测定硅质、铝质、镁质和铬质耐火材料中15种组分[J].冶金分析,2019,39(2):71-76. CUI Hongli.Determination of fifteen components in siliceous,aluminum,magnesia and chrome refractory materials by X-ray fluorescence spectrometry with fusion sample preparation[J].Metallurgical Analysis,2019,39(2):71-76. [6] 王显,王文焱.ICP-AES测定锌铝镁板镀层中镁、铝、硅、锑的含量[J].河北冶金,2020(3):76-79. WANG Xian,WANG Wenyan.Determination of Mg, Al, Si and Sb content in Zn-Al-Mg plate coating by ICP-AES[J].Hebei Metallurgy,2020(3):76-79. [7] 袁润蕾,于亚辉,刘军,等.电感耦合等离子体原子发射光谱法测定土壤中8种组分[J].冶金分析,2019,39(11):50-56. YUAN Runlei,YU Yahui,LIU Jun,et al.Determination of eight components in soil by inductively coupled plasma atomic emission spectrometry[J].Metallurgical Analysis,2019,39(11):50-56. [8] 中国国家标准化管理委员会.GB/T 5069—2015 镁铝系耐火材料化学分析方法[S].北京:中国标准出版社,2015. [9] 孟丽丽.酸溶ICP-AES法测定铝硅系耐火材料中8种次量元素[J].山东冶金,2021,43(6):21-23. MENG Lili.Determination of eight minor elements in Al Si refractories by acid melting ICP-AES[J].Shandong Metallurgy,2021,43(6):21-23. [10] 刘建华,戴文杰,常欢.EDTA滴定联测硅钙钡镁中钙钡镁指示剂的选择[J].包钢科技,2015,41(3):55-59. LIU Jianhua,DAI Wenjie,CHANG Huan.Selection of indicator for simultaneous determination of calcium,barium and magnesium in silicon-calcium-barium-magnesium alloy with EDTA compleximetry[J].Science and Technology of Baotou Steel,2015,41(3):55-59.
