Abstract:Gold ore is a critically valuable mineral resource, in which silver serves as an important associated element. When evaluating the economic value of gold ore, it is essential to accurately determine not only the gold content but also the silver content. Existing national standard methods for gold ore analysis require separate determination of gold and silver, primarily due to differences in their pretreatment procedures. The conventional process for gold determination involves roasting to remove carbon and sulfur, digestion with aqua regia, enrichment, and final measurement after elution. In contrast, silver is typically determined via digestion with a mixture of four acids. However, the roasting step leads to the loss of silver, and the enrichment process further contributes to silver loss, making simultaneous determination of gold and silver unachievable.This study introduces the use of hypochlorous acid in a nitric acid medium to oxidize carbonaceous matter and sulfides, thereby replacing the roasting step. Subsequently, 50 mL of aqua regia (1+1) is added to continue sample digestion. After dilution to a final volume of 100 mL, a 5 mL aliquot of the sample solution is further diluted to 25 mL. To address the interference of iron in the determination of gold by ICP-OES, D401 dry-state chelating resin is employed to remove iron, enabling the simultaneous determination of gold and silver in gold ore.In this study, activated carbon and graphite carbon were used to validate the optimal amount of hypochlorous acid and digestion time. Standard solutions of gold and iron were prepared, and the interference magnitude of iron on gold determination was investigated using ICP-OES. Experiments were conducted using standard solutions of gold, silver, and iron, along with certified reference materials for gold ore—GBW07803a (with TFe2O3 content of approximately 14.86%) and GBW(E)070236 (with TFe2O3 content of 15.75% ± 0.19%)—to determine the optimal amount of D401 macroporous polystyrene-based chelating resin and shaking time for iron adsorption, as well as the impact of iron adsorption on the determination of gold and silver.The results indicate that the addition of 7 mL of hypochlorous acid effectively replaces roasting, eliminating carbonaceous matter and sulfides in the sample. When the iron content exceeds 25 times that of gold, it significantly interferes with the determination. The optimal conditions for removing iron interference were achieved with 10 g of D401 macroporous polystyrene-based chelating resin and a shaking time of 10 minutes, which eliminated the interference of iron on gold determination without affecting the determination of silver.The proposed method was applied to the analysis of three gold ore certified reference materials—GBW(E)070264, GBW(E)070268, and GBW(E)070269. The relative errors (RE) between the measured values and the certified values ranged from 0.54% to 1.40%, and the relative standard deviations (RSD, n=7) ranged from 1.01% to 2.38%. These results meet the accuracy and precision quality control requirements specified in the "Quality Management Regulation for Geological and Mineral Laboratory Testing" (DZ/T 0130-2006). Additionally, a method comparison was conducted between the proposed method and the national standard method "Chemical Analysis Methods for Gold Ores" (GB/T 20899-2019) using two practical gold ore samples. The RSDs of the proposed method (n=7) ranged from 0.50% to 0.92%, and the relative errors between the measured values and those obtained by the standard method were all ≤0.68%, confirming the accuracy of the proposed method.This method resolves the challenge of simultaneous determination of gold and silver in gold ore, offering a simplified procedure that saves time and labor.