碱熔-水蒸气蒸馏-离子色谱法测定锌精矿中的氟

Determination of Fluoride in Zinc Concentrate by Alkali Melt-Water Vapor Distillation-Ion Chromatography

建立了一种测定锌精矿中氟含量的分析方法。通过碱熔半熔融方法，除去锌精矿中大量硫对样品前处理的影响，利用水蒸气蒸馏的方法分离了被测元素氟与矿石中其它大量重金属离子。通过碱熔-水蒸气蒸馏后离子色谱测定，最大限度排除干扰，降低测定检出限。以碳酸钠（2．5mmol／L）和碳酸氢钠（3．5mmol／L）混合溶液作为淋洗液，SH-AC-1（200mm×4．6mm ID）阴离子分析柱分离，抑制电导检测器检测。线性范围内相关系数为0．9996，加标回收率97％-102％，相对标准偏差小于4．0％，样品检出限0．0004％。有效拓展了锌精矿中氟含量的测定范围。

A method for determination of fluoride content in zinc concentrates was established. By alkali fusion together with semi-melting method, the influence of a large number of sulfur on sample pretreatment was removed. The floride that to be analyzed was separated from many other heavy metal ions in ores using water vapor distillation. After alkali fusion and water vapor distillation process, the interference in ion chromatographic determination was eliminated to the greatest extent and the detection limit was decreased. Sodium carbonate （2.5 mmol/L） and sodium bicarbonate （3.5 mmol/L） mixture solution was used as eluent and SH-AC-1 （200 mmX4.6 mm ID） was used as anion analytical column for separation. A suppressed conductivity detector was for detection. As a result, the linear ranges of the method for fluoride in the zinc concentrate were 0. 004% - 0.5% and the correlation coefficient was 0. 999 6. The standard addition recoveries were 97%-102%and the relative standard deviation was less than 4.0%. The sample detection limit was 0. 0004%. The method effectively expands the contents of fluoride in zinc concentrate that can be determined.