Determination of P, Mg, Al and Fe in Phosphate Ores by Inductively Coupled Plasma-Atomic Emission Spectrometry
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摘要: 运用电感耦合等离子体发射光谱法(ICP-AES)分析磷矿石样品中的多元素,通常采用氢氟酸+盐酸+硝酸混合酸分解石样品,其中的氢氟酸是为了彻底分解地质样品中以硅酸盐形式存在的待测元素,但赶除氢氟酸的程序繁琐。本文在实际工作中发现,仅需测定磷矿石中的磷、镁、铝、铁元素时,可不加氢氟酸,四种元素的分析结果已能满足要求,这可能是与样品处理过程中生成的少量氢氟酸有关。为了验证不加氢氟酸的样品分解能力,采用浓硝酸-浓盐酸混合酸(体积比1:1)加热分解试样,稀酸浸取,溶液冷却定容后直接用ICP-AES测定。分析结果显示溶样酸中是否含有氢氟酸,对磷、镁、铝、铁的测定结果不存在显著影响。方法检出限为磷100 μg/g、镁0.3 μg/g、铝20 μg/g和铁6 μg/g。经国家一级标准物质分析验证,方法精密度( RSD)小于5.0%,相对误差小于1.5%。本方法针对性强,分析快速准确,适用于实际工作中不包括钙和硅元素在内的磷矿石简项测定。Abstract: The traditional method for determining multiple elements in phosphate ores is to decompose the phosphate ore samples with a mixture of HNO3, HCl and HF, and take measurements using Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). The addition of HF thoroughly decomposes silicates in which the target elements are found. However, the process of HF removal is very complicated. A rapid sample processing method has been determined to simplify the method. If only four elements of P, Mg, Al and Fe need to be determined, the addition of HF is unnecessary, which may be related to a small amount of HF introduced during the samples processing by HNO3 and HCl. In order to verify the decomposition capacity of the mixed acids, phosphate ores samples were decomposed in a conical flask with mixed acids of HNO3 and HCl (HNO3:HCl=1:1) without HF, and dissolved with dilute acid solution, then the sample solution was determined directly by inductively coupled plasma-atomic emission spectrometry. Analysis results show that there is no significant impact on the results of P, Mg, Al and Fe, and the detection limits of the method were 100 μg/g (P), 0.3 μg/g (Mg), 20 μg/g (Al) and 6 μg/g (Fe), respectively. The presented method has been applied to the determination of P, Mg, Al and Fe in the national standard reference materials. The results show that the determination precision (RSD) is better than 5% (n=12) and the relative error is less than 1.5%. The method has advantages of high accuracy, simplicity and rapidity, and can meet the demands of practical analysis for phosphate ores without Ca and Si elements.
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表 1 ICP-AES仪器工作条件
Table 1. Working parameters of the ICP-AES instrument
工作参数 设定条件 载气(Ar)流量 0.5 L/min 辅助气(Ar)流量 0.6 L/min 冷却气(Ar)流量 16 L/min 功率 1200 W 雾化气压力 0.2 MPa 光室温度 (38±0.1)℃ 表 2 混合标准溶液系列浓度
Table 2. The concentration of mixed standard solution series
元素 浓度(μg/mL) 空白溶液 标准系列1 标准系列2 标准系列3 标准系列4 P 0 50 100 200 500 Mg 0 10 50 100 200 Al 0 10 20 50 100 Fe 0 10 20 50 100 表 3 两种混合酸溶解标准物质GBW 07212的分析结果
Table 3. The analytical results of elements in standard sample GBW 07212 with two mixed acid systems
标准物质编号 待测元素 标准值(%) 测定值(%) 浓硝酸+浓盐酸(1:1) 氢氟酸+盐酸+硝酸(1:1:1) GBW 07212(磷矿石) P2O5 6.06 6.09 6.03 MgO 7.12 7.13 7.14 Al2O3 4.06 4.08 4.06 Fe2O3 3.08 3.12 3.07 CaO 19.42 17.33 19.44 SiO2 38.8 2.11 - K2O 2.63 2.44 2.64 Na2O 0.14 0.12 0.13 表 4 方法精密度与准确度
Table 4. Precision and accuracy tests of the method
标准物质编号 待测元素 含量(%) 相对误差(%) RSD(%) 标准值 测定值 GBW 07212(磷矿石) P2O5 6.06 6.09 0.50 0.4 MgO 7.12 7.13 0.14 0.8 Al2O3 4.06 4.08 0.50 0.7 Fe2O3 3.08 3.12 1.30 1.7 GBW 07211(磷矿石) P2O5 20.86 20.82 -0.19 0.3 MgO 8.19 8.20 0.12 0.7 Al2O3 2.28 2.27 -0.44 4.2 Fe2O3 1.08 1.09 0.93 3.7 -
[1] 岩石矿物分析编委会.岩石矿物分析(第四版 第二分册)[M].北京:地质出版社,2011:206-262.
[2] GB/T 1871.1—1995,磷精矿和磷矿石中磷铁铝钙镁含量的分析方法[S].
[3] 朱祯彪.比色法连续测定磷酸中铁、铝的含量[J].云南化工,2001,28(2):27-29. http://www.cnki.com.cn/Article/CJFDTOTAL-YNHG200102014.htm
[4] 彭桦,沈潜.3,5-diBr-PADAP作指示剂连续测定磷矿石中铁和铝[J].磷肥与复肥,2004,19(6):70.
[5] 潘旭.比色法连续测定磷矿石中铁、铝的含量[J].磷肥与复肥,1999,14(6):62-63,79. http://www.cnki.com.cn/Article/CJFDTOTAL-LFYF199906029.htm
[6] 陈万明.磷矿石中磷的测定方法探讨[J].广州化工,2011,39(14):102-104. doi: 10.3969/j.issn.1001-9677.2011.14.037
[7] 孙琳.磷矿石中磷、钙、镁、锶、氟测定方法评述[J].贵州地质,2007,24(4):322-324. http://www.cnki.com.cn/Article/CJFDTOTAL-GZDZ200704022.htm
[8] 李明来,王良士,彭新林,杨桂林,黄小卫,龙志奇.电感耦合等离子体原子发射光谱法测定磷矿中微量稀土元素[J].冶金分析,2010,30(1):47-50. http://www.cnki.com.cn/Article/CJFDTOTAL-YJFX201001011.htm
[9] 郭振华.电感耦合等离子体发射光谱法测定磷矿石中常量元素硅磷硫钙镁铝铁钛锰[J].岩矿测试,2012,31(6):446-449. http://www.cnki.com.cn/Article/CJFDTOTAL-YKCS201203014.htm
[10] 冯晓军,罗廉明,陈晶亮,姜威.电感耦合等离子体发射光谱法快速测定磷矿石中主次量组分[J].岩矿测试,2009,28(4): 399-400. http://www.cnki.com.cn/Article/CJFDTOTAL-YKCS200904026.htm
[11] 罗晓光,郭惫娴,朱丹兮.电感耦合等离子体发射光谱法同时测定磷矿和磷肥样品中高含量磷及其他常量元素[J].分析化学,1992,20(7): 866. http://www.cnki.com.cn/Article/CJFDTOTAL-FXHX199207036.htm
[12] 陈加希.ICP-AES法同时测定磷矿石中钙、镁、铁、铝、锰、铅、锌、钒和铬[J].云南冶金,1992(4):54-59.
[13] 彭桦,王燕敏,李翠英,李北宣,王云华.采用微波封闭溶样电感耦合等离子体法测定磷矿组成[J].磷肥与复肥,2010,25(3): 71-72. http://www.cnki.com.cn/Article/CJFDTOTAL-LFYF201003034.htm
[14] 陈名樑.磷矿中七种金属元素的光谱法测定[J].山西冶金,2004,93(1):36-37. http://www.cnki.com.cn/Article/CJFDTOTAL-SDYZ200401016.htm
[15] 冯晓军,薛菁.ICP-AES法测定磷矿中的氧化锶[J].磷肥与复肥,2012,27(9):84-85. http://www.cnki.com.cn/Article/CJFDTOTAL-LFYF201205034.htm
[16] 黎香荣,韦万兴,崔翔,罗明贵,陈永欣,马丽方.电感耦合等离子体发射光谱法测定磷矿石中微量有毒元素铅砷镉[J].岩矿测试,2009,28(4):370-372. http://www.cnki.com.cn/Article/CJFDTOTAL-YKCS200904015.htm
[17] 刘国文,王旭刚,崔东胜,龚福忠.微波消解-火焰原子吸收光谱法测定磷矿石中铅[J].冶金分析,2010,30(10):54-57. doi: 10.3969/j.issn.1000-7571.2010.10.012
[18] 熊言林,董吉溪,程立.用盐酸分解磷矿石的试验[J].安徽师大学报(自然科学版),1993,16(4):37-40. http://www.cnki.com.cn/Article/CJFDTOTAL-AHSZ199304008.htm
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