Determination of fluoride and chloride in sulfide ores by steam distillation ion chromatography
YANG Zhao-hong1,LI Hua-chang*2,YU Li2,SHI Ye-hong2
1.College of Chemistry and Biology Engineering,Guilin University of Technology,Guilin 541006, China; 2.Sub-institute of Analytical Chemistry,Beijing General Research Institute of Mining and Metallurgy,Beijing 100044,China
Abstract：Sulfide ores contain high content of sulfur which would be distilled in the form of hydrogen sulfide and elementary sulfur upon conventional steam distillation, rendering an incomplete purification of the to-be-tested sample. Meanwhile, as the distillation process was conducted in sulfuric acid, the distillate would introduce a certain amount of sulfuric acid. Excessive concentration of sulfate radical would increase the leaching time and get in the way of system maintenance. Therefore, the experiment improved the steam distillation method in this way: the sulfide ores samples were decomposed in sulfuric acid and subjected to distillation in steam within the temperature range of 160-180 ℃, with the involvement of potassium bichromate, an oxidant, to oxidize negative bivalent sulfur ion into sulfate radical and reduce the content of sulfur ion in the distillate. The distillate, upon the purification through D860 Barium type cation exchange resin and the removal of its sulfide radical and chromate radical, was subjected to the measurement of the content of fluorine ion and chloride ion by means of ion chromatography. With the mixture solution of 4.5 mmol/L NaHCO3 and 2.7 mmol/L Na2CO3 serving as the eluent, upon the separation through the SH-AG-1 guard column and SH-AC-1 separation column, fluorine ion and chloride ion showed a linear correlation with the peak area within the range of 0.2-2.0 and 0.5-5.0 mg/L with correlation coefficients of 0.999 5 and 0.999 2, respectively. The detection limit was 0.006 and 0.010 mg/L, respectively. The method was applied to the analysis on samples from copper sulfide concentrate and zinc sulfide concentrate, registering an addition standard recovery for fluorine ion and chloride ion at the range of 96.0%-98.0% and 96.0%-97.6%, and a range of relative standard deviation (RSD, n=11) at 1.3%-3.1% and 1.2%-4.0%, respectively.
阳兆鸿，李华昌，于力，史烨弘. 水蒸气蒸馏-离子色谱法测定硫化矿石中氟和氯[J]. 冶金分析, 2015, 35(4): 34-38.
YANG Zhao-hong,LI Hua-chang,YU Li,SHI Ye-hong. Determination of fluoride and chloride in sulfide ores by steam distillation ion chromatography. , 2015, 35(4): 34-38.
