微波消解-磺基水杨酸光度法测定磷矿石中铁

发布时间：2018-06-23 01:08

本文选题：微波消解 + 磺基水杨酸　；参考：《冶金分析》2017年01期

【摘要】：磺基水杨酸光度法测定铁是比较经典的方法,但对于磷矿石,采用敞口聚四氟乙烯烧杯在电热板上溶矿过程中溶液易喷溅,且显色时在pH 8~11溶液中,PO_4~(3-)会跟磷矿石中的Ca~(2+)、Mg~(2+)反应生成沉淀而影响铁的测定,同时含锰高的磷矿石中的Mn~(2+)也会对铁的测定产生干扰。因此实验在HNO_3-HF-SSA(磺基水杨酸)混合酸里采用密闭高压微波消解技术快速消解各种磷矿石,并通过磺基水杨酸光度法在六次甲基四胺介质中测定磷矿石中铁(以Fe_2O_3形式表示)。考察确定了微波消解条件(功率400 W、压力0.5 MPa、消解时间10min)和混合酸的最佳用量(2mL HNO_3-5mL HF-2mL 200g/L SSA溶液),并对磷矿石国家标准物质和实际样品分析,结果表明,实验方法与国家标准方法(GB/T 1871.2—1995)以及电感耦合等离子体原子发射光谱法(ICP-AES)测定结果一致,测定值与认定值一致,相对标准偏差(RSD,n=5)在2%以内,可满足磷矿石中0.05%~10%三氧化二铁的测定要求。
[Abstract]:The spectrophotometric determination of iron with sulfosalicylic acid is a classical method, but for phosphate rock, the solution is easy to spatter in the process of dissolving ore with open PTFE beaker on the electrothermal plate. Moreover, the reaction of PO4- 3- with Ca ~ (2) and mg ~ (2) in phosphate rock in pH 8 ~ (11) solution will result in precipitation, which will influence the determination of iron. Meanwhile, mn ~ (2) in phosphate rock with high manganese content will also interfere with the determination of iron. Therefore, in the HNO3-HF-SSA mixed acid, all kinds of phosphate rock were rapidly digested by closed high pressure microwave digestion, and the iron in phosphate ore was determined by sulfosalicylic acid spectrophotometry in hexomethylenetetramine medium (expressed as Fe _ 2O _ 3 / S _ 2O _ 3). The conditions of microwave digestion (power 400W, pressure 0.5MPa, digestion time 10min) and the optimum dosage of mixed acid (2mL HNO3-5mL HF-2mL 200g / L SSA solution) were determined. The experimental method is consistent with the national standard method (GB / T 1871.2-1995) and the inductively coupled plasma atomic emission spectrometry (ICP-AES). The measured value is in agreement with the determined value, and the relative standard deviation (RSDN) is less than 2%. It can meet the requirement of determination of 0. 05% iron trioxide in phosphate rock.
【作者单位】：河北地勘局唐山实验测试所;
【分类号】：P575;O657.3

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