水蒸气蒸馏/离子色谱法测定磷矿石中氟化物和氯化物

Simultaneous Determination of Fluoride and Chloride in Phosphorus Rock by Steam Distillation-Ion Chromatography

建立了离子色谱法同时测定磷矿石中氟化物和氯化物的检测方法.利用国产的YSA-8型分离柱和DZS电自生型抑制器将日本岛津LC-10A液相色谱仪改造为抑制型离子色谱仪,用4.3 mmol/L Na2O3-6.0mmol/L NaHCO3混合溶液作淋洗液.试样用稀硫酸溶解,以水蒸气蒸馏法将磷矿石中氟化物和氯化物从样品中分离,用0.45μm微孔滤膜过滤后,进样分析.方法的相关性好(r＞0.999),氟化物、氯化物测定的相对标准偏差分别为2.1%～2.6%、2.5%～3.8%,样品的加标回收率分别为93%～104%、95%～98%,与电位滴定法作对比测定的结果表明,方法的准确度较高.本方法线性范围宽、操作简便、快速,非常适合磷矿石中氟化物、氯化物的检测.

An ion chromatographic method for simuhaneous determination of fluoride and chloride in phosphorus rock using steam distillation for sample pretreatment was developed. The HPLC （Shimadzu LC-10A） was converted into a suppressor ion chromatograph by using the YSA-8 column（China made） for separation and the DZS self-electric suppressor for suppression. The eluent was a mixture of 4.3 mmol/L Na2CO3 and 6.0 mmol/L NaHCO3. After dissolving the sample with sulfuric acid, the fluoride and chloride were separated from the matrices by steam distillation. The distillate, after passing through the 0.45 μm filter membrane, was used for analysis. Under optimal conditions, the correlation coefficients of the calibration curves for fluoride and chloride were 0.9996 and 0.9994, respectively and the detection limits（ S/N = 3） were 2 mg/kg and 3 mg/kg, respectively. The relative standard deviations for fluoride and chloride were 2.1% - 2.6% and 2.5% -3.8%, respectively and the recoveries were 93% - 104%, and 95% -98%, respectively. The method has been applied to the determination of fluoride and chloride in phosphorus rock samples with satisfactory results.