水蒸气蒸馏-离子色谱法测定湿法炼锌溶液中氟和氯

将水蒸气蒸馏和离子色谱法相结合建立了湿法炼锌溶液中氟和氯的测定方法。在硫酸(2+1)介质中,于165~175 ℃的温度下将样品蒸馏25 min,蒸馏过程中生成的氟化氢和氯化氢随着水蒸气通过冷凝管冷却,然后流入接收瓶,被氢氧化钠碱液吸收。吸收液通过直径为0.22 μm水系滤膜,进入离子色谱仪,氟和氯离子被测定。样品中的基体及与氟、氯离子共存的其他离子对测定没有干扰。氟离子和氯离子的质量浓度分别在0.2~2 mg/L和0.5~5 mg/L范围内与其对应的峰面积呈良好的线性关系,线性回归方程分别为y=0.661 x-0.398和y=0.827 x,检出限分别为0.006 mg/L和0.01 mg/L。方法用于湿法炼锌溶液的合成液和预上清液中氟和氯的测定,合成液的测定值与参考值相符合,相对标准偏差(n=11)分别为3.2%(F)和4.0%(Cl);预上清液中氟和氯的测定值分别为40.0 mg/L和371 mg/L,回收率分别为91%和88%。

Determination of fluorine and chlorine in solution of wet zinc hydrometallurgy by steam distillation-ion chromatography

The determination method of fluorine and chlorine in solution of wet zinc hydrometallurgy by steam distillation-ion chromatography was established. The sample was distilled in steam at 165-175°C for 25 min in sulfuric acid (2+1) medium. The hydrogen fluoride and hydrogen chloride generated in distillation process with steam passed through condenser pipe to cool, and flowed into the receiving bottle to be absorbed by sodium hydroxide solution. The absorption solution was filtered with microfiltration membrane with pore size of 0.22 μm. Then, the content of fluorine and chlorine irons in filtrate was determined by ion chromatography. The matrix and coexisting ions in sample had no interference in the determination of fluorine and chlorine. The mass concentration of fluorine and chlorine ions in range of 0.2-2 mg/L and 0.5-5 mg/L showed good linear relationship to the corresponding peak area. The equation of linear regression was y=0.661 x-0.398 and y=0.827 x, respectively. The detection limit was 0.006 mg/L and 0.01 mg/L, respectively. The proposed method was applied to the determination of fluorine and chlorine in synthetic fluid and pre-supernatant liquid of solution of wet zinc hydrometallurgy. The found results of synthetic fluid were consistent with the reference values, and the relative standard deviation (RSD, n=11) was 3.2% (F) and 4.0% (Cl). The determined results of fluorine and chlorine in pre-supernatant liquid were 40.0 mg/L and 371 mg/L, and the recoveries were 91 % and 88 %, respectively.