Feasibility of pyrohydrolysis and extended-steam distillation method for the extraction of two halides from zinc and lead concentrate samples followed by ion chromatography analysis

Abstract

This study illustrates the feasibility of two digestion methods namely pyrohydrolysis (PH) and extended-steam distillation (E-SD) for the effective extraction of two halides (F− & Cl−) from six complex inorganic zinc and lead concentrate samples, followed by their determination with ion chromatography (IC). Although both digestion methods appeared feasible, but E-SD exhibited slightly better spiked-recovery values for both analytes at two concentration levels (0.25 mg/L, 0.50 mg/L). Various parameters of pH such as sample mass, temperature, flow rate of water vapor, concentration, and volume of absorption solution were optimized in order to achieve the optimum extraction recovery of both halides from six complex inorganic zinc and lead concentrate samples. Both methods exhibited satisfactory analytical figures of merit viz. excellent linearity with a determination coefficient (R2) greater than 0.9997, better LODs and LOQs (0.0002–0.0011 mg/kg), satisfactory recoveries (80.21–98.87%), negligible or no matrix effect (97.89%−104.45%), and intra- and inter-day precision values of less than 3.28%. Hence, both methods appeared feasible as no statistical discrepancies (p > 0.05) were observed among the obtained results except for few chlorides. Besides, the results of both methods were in good agreement with certified reference values of the “Zn-Australia” sample (ANOVA/t-test, the confidence level of 95%). Thus proposed study provides two simple, efficient, and cost-effective choices for the sensitive and selective determination of both halides in complex inorganic samples.