Abstract:The total chlorine content is one of the important indicators for evaluating the quality of iron ore, so it is important to establish a method for determination of total chlorine content in iron ores. The difficulty for determination of total chlorine in iron ore by X-ray fluorescence spectrometry (XRF) lies in the fact that chlorine is easily polluted, lost at high temperature, and lack of certified reference materials containing chlorine with sufficient concentration span. The sample was pre-dried at 105 ℃ and then directly fused with the mixed flux (lithium tetraborate and lithium metaborate were mixed at mass ratio of 12∶22), avoiding the possible contamination of chlorine and loss of chlorine in pre-ignition oxidation process. The calibration sample series with certain concentration gradients were prepared with sodium chloride of primary reagent and ferric oxide of high purity reagent to draw the calibration curve. The matrix effects among elements were corrected by the theoretical α coefficient method. The determination of total chlorine in iron ore was realized by wavelength dispersion-XRF with fusion sample preparation. The linear correlation coefficient of calibration curves was 0.999 6. The detection limit was 0.003 2% (mass fraction, the same below), and the detection range was 0.016%-1.2%. Four iron ore samples were selected, and 11 sample sheets were prepared and determined in parallel according to the proposed method, respectively. The relative standard deviations (RSD, n=11) of determination results were between 0.28% and 3.9%. 7 certified reference materials and 4 synthetic samples of iron ore prepared with sodium chloride of primary reagent and ferric oxide of high purity reagent were determined according to the proposed method. The results showed that the average found (AVE) of 10 samples was within the expanded uncertainty scope of standard value/reference value (Ac). The difference of AVE and Ac for the other certified reference material was slightly higher than the expanded uncertainty, but AVE-Ac≤C, indicating that there was no significant statistical discrepancy between the determination result and standard value. The further t test showed that there was no significant difference between AVE and Ac for these 11 samples.
[1] 郭华楼, 胡宾生, 贵永亮.煤粉中的氯在高炉冶炼过程中的行为[J].中国冶金, 2010(11):12-15. GUO Hualou, HU Binsheng, GUI Yongliang.Behavior on blast furnace smelting process of chlorine in coal[J].China Metallurgy, 2010(11):12-15. [2] 李婷, 任丽萍, 闵红, 等.燃烧炉-离子色谱联用法测定铁矿石中的氯[J].冶金分析, 2018, 38(7):51-56. LI Ting, REN Liping, MIN Hong, et al.Determination of chlorine in iron ore by combustion furnace-ion chromatography[J].Metallurgical Analysis, 2018, 38(7):51-56. [3] 中华人民共和国国家质量监督检验检疫总局, 国家认证认可监督管理委员会.SN/T 3919—2014 铁矿石中水溶性氯化物含量的测定 离子色谱法[S].北京:中国标准出版社, 2014. [4] 中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会.GB/T 6730.69—2010 铁矿石 氟和氯含量的测定 离子色谱法[S].北京:中国标准出版社, 2010. [5] 中华人民共和国国家质量监督检验检疫总局, 国家认证认可监督管理委员会.SN/T 2261—2009 铁矿中水溶性氯化物的测定 电位滴定法[S].北京:中国标准出版社, 2009. [6] 国家市场监督管理总局, 国家标准化管理委员会.GB/T 6730.64—2022 铁矿石 水溶性氯化物含量的测定 离子选择电极法[S].北京:中国标准出版社, 2007. [7] 孟庆森, 谷博, 枫亚辉, 等.X射线荧光光谱法测定铁矿中的主次量元素[J].质量安全与检验检测, 2021(3):33-35. MENG Qingsen, GU Bo, FENG Yahui, et al.Determination of primary and secondary elements in iron ore by X-ray fluorescence spectrometry[J].Quality Safety Inspection and Testing, 2021(3):33-35. [8] 刘金, 陈燕波, 王迪民, 等.熔融制样-X射线荧光光谱法测定高磷铁矿中主量元素[J].华南地质与矿产, 2017, 33(2):193-197. LIU Jin, CHEN Yanbo, WANG Dimin, et al.Determination of major elements in high-phosphorus iron ore by X-ray fluorescence spectrometry with fusion sample preparation[J].Geology and Mineral Resources of South China, 2017, 33(2):193-197. [9] 张文宇, 许晓慧.熔融制样-X射线荧光光谱法测定铝矿、铁矿、钙矿、镁矿和锰矿中主要组分[J].冶金分析, 2022, 42(4):83-89. ZHANG Wenyu, XU Xiaohui.Determination of major components in aluminum ore, iron ore, calcium ore, magnesium ore and manganese ore by X-ray fluorescence spectrometry with fusion sample preparation[J].Metallurgical Analysis, 2022, 42(4):83-89. [10] 张涛, 陈朝阳, 陈景伟.粉末压片-能量色散X射线荧光光谱法测定多金属矿石中锡[J].冶金分析, 2023, 43(2):23-30. ZHANG Tao, CHEN Zhaoyang, CHEN Jingwei.Determination of tin in polymetallic ore by energy dispersive X-ray fluorescence spectrometry with powder pellet preparation[J].Metallurgical Analysis, 2023, 43(2):23-30. [11] 黄嘉庆, 仝晓玲, 李子权, 等.XRF滤纸片法测定镍铜锌铁氧体材料的主量成分[J].广东化工, 2016, 43(18):157-158. HUANG Jiaqing, TONG Xiaoling, LI Ziquan, et al.Determination of major components of the nickel-copper-zinc-ferrites by XRF filter paper thin piece method[J].Guangdong Chemical Industry, 2016, 43(18):157-158. [12] 彭桦, 张东云, 姜鸥, 等.X射线荧光光谱滤纸片法测定有机成分高的土壤中的总磷[J].磷肥与复肥, 2009, 24(3):66-67. PENG Hua, ZHANG Dongyun, JIANG Ou, et al.Determination of total phosphorus in the soil with highly organic components by X-ray fluorescence filter paper chromatographic method[J].Phosphate & Compound Fertilizer, 2009, 24(3):66-67. [13] 中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会.GB/T 6730.62—2005 铁矿石 钙、硅、镁、钛、磷、锰、铝和钡含量的测定 波长色散X射线荧光光谱法[S].北京:中国标准出版社, 2005. [14] 李强, 雷知生, 张学华, 等.熔融制样-X射线荧光光谱法测定珊瑚礁样品中15种主次和微量组分[J].冶金分析, 2022, 42(11):30-36. LI Qiang, LEI Zhisheng, ZHANG Xuehua, et al.Determination of fifteen major, minor and micro components in coral reef samples by X-ray fluorescence spectrometry with fusion sample preparation[J].Metallurgical Analysis, 2022, 42(11):30-36. [15] 万芒, 刘伟, 曾小平.熔融制样-X射线荧光光谱法测定稀土硅铁中11种主次元素[J].冶金分析, 2023, 43(1):54-61. WAN Mang, LIU Wei, ZENG Xiaoping.Determination of 11 major and minor elements in rare earth ferrosilicon by X-ray fluorescence spectrometry with fusion sample preparation[J].Metallurgical Analysis, 2023, 43(1):54-61. [16] The International Organization for Standardization.ISO/TR 16043:2015(E) Iron ores-Determination of chlorine content-X-ray fluorescence spectrometric method[R].Switzerland:ISO, 2015. [17] 中华人民共和国国家质量监督检验检疫总局, 中国国家标准化管理委员会.GB/T 27417—2017 合格评定 化学分析方法确认和验证指南[S].北京:中国标准出版社, 2017. [18] 周尊英.实用统计技术指南[M].北京:中国标准出版社, 2003:121-126.