碱熔-电感耦合等离子体原子发射光谱法测定钒钛磁铁矿中钒和钛

钒钛磁铁矿是重要的炼钢原料,其中的钒、钛元素具有极高的综合利用价值。钒、钛元素的测定方法多样,其中化学湿法手段繁琐,而先采用微波消解法处理样品,再使用电感耦合等离子体原子发射光谱法(ICP-AES)测定需附加溶样设备,成本较高。样品采用硼酸-碳酸钠混合熔剂在1 000 ℃熔融、盐酸浸出的方法溶解样品,选择V 309.311 nm、Ti 334.941 nm为分析谱线,采用基体匹配法绘制校准曲线消除基体效应的影响,采用电感耦合等离子体原子发射光谱法(ICP-AES)测定钒钛磁铁矿中钒和钛。钒和钛的校准曲线线性相关系数均大于0.999,方法检出限均为0.000 5%。按照实验方法测定钒钛磁铁矿国家标准样品GBW07225、GBW07226a、GBW07227中钒、钛,结果的相对标准偏差(RSD,n=7)小于4%,测定值与认定值相一致。选择3个钒钛磁铁矿实际样品,分别按照实验方法和国家标准方法GB/T 6730.31—2017(分光光度法测定钒)及GB/T 6730.23—2006(滴定法测定钛)测定钒和钛,结果相一致。

Determination of vanadium and titanium in vanadium-titanium magnetite by alkali fusion-inductively coupled plasma atomic emission spectrometry

Vanadium-titanium magnetite is an important raw material for steel making. The vanadium and titanium elements have very high comprehensive utilization value. There are many methods for the detection of vanadium and titanium, wherein chemical wet method is complicated. The additional sample dissolving equipment is required for the determination by inductively coupled plasma atomic emission spectrometry (ICP-AES) after sample treatment by microwave digestion, so the cost is high. The sample was firstly fused with boric acid-sodium carbonate mixed flux at 1 000 ℃ followed by leaching with hydrochloric acid. V 309.311 nm and Ti 334.941 nm were selected as the analytical lines. The matrix matching method was used to prepare the calibration curve to eliminate the influence of matrix effect. The contents of vanadium and titanium in vanadium-titanium magnetite were determined by ICP-AES. The linear correlation coefficients of calibration curves for vanadium and titanium were both higher than 0.999. The limits of detection of method were both 0.000 5%. The contents of vanadium and titanium in national standard samples of vanadium-titanium magnetite (GBW07225, GBW07226a and GBW07227) were determined according to the experimental method. The relative standard deviations (RSD, n=7) of measurement results were less than 4%. The found results were consistent with the certified values. Three actual samples of vanadium-titanium magnetite were determined according to the experimental method, and the results were consistent with those obtained by national standard methods (GB/T 6730.31-2017 Determination of vanadium by spectrophotometry, and GB/T 6730.23-2006 Determination of titanium by titration).