Uncertainty Evaluation for Iodometric Determination of Gold in Gold Ores with Activated Carbon Adsorption

According to the evaluation method to measure uncertainty, we evaluated the uncertainty of the gold determination in ore by using activated carbon adsorption-iodimertric. The experimental samples were calcined from room temperature to 650℃ for 2 h to remove sulphur, then dissolved by the 50% (volume fraction) aqua regia for 1 h. The gold was absorbed from the solution by activated carbon dynamic adsorption suction filter. The carried gold carbon cineration was dissolved again before the gold was titrated by sodium hyposulfite standard solution. This method is simple, rapid and strong practicability. The uncertainties of measurement consist of the consumed volumes and titer of sodium hyposulfite standard solution to gold, sample weight, duplications and so on. The standard uncertainty was obtained by quantifing and synthesizing each branch of uncertainties measurement results, then converted into the expansion uncertainty. The result indicates that the main uncertainty is from the titer of sodium hyposulfite standard solution.