Determination of Chloride and Sulfate in Trona Ores by Ion Chromatography

Through the determination of chloride and sulfate, the contents of salt and sodium sulfate in natural trona ore can be obtained. At present analysis methods are inefficient, causing disadvantages, such as having a time-consuming process, easy pollution and low production efficiency. This study establishes the analysis method which detects chloride and sulfate in natural trona ore by the ion chromatography-suppression conductivity measurement. The anions were dissolved into the solution by hot water and the chloride and sulfate were separated by using AG-19 type anion protect column and AS-19 type anion separation column with 30 mmol/L KOH as the eluent. The interference from carbonate ion was eliminated by a Carbonate Removal Device (CRD). Under optimal conditions, the detection limits of chloride and sulfate were 0.01 and 0.02 mg/L, respectively. The recoveries were between 100.9%-104.1% and the precisions of the method (RSD, n=10) were less than 2.5%. The results for the actual samples were consistent with those obtained by the titration method. This method is simple and avoids interferences by the complicated components of the sample and the buffer solution system, while also being economical, accurate, giving good reproducibility and high sensitivity.