The determination of the amount of silver present in a concentrate is a crucial process in the mining industry. Various analytical techniques, such as fire assay, atomic absorption spectroscopy, and inductively coupled plasma mass spectrometry, are employed to determine the silver content in concentrates. The working range of these methods can vary depending on the complexity of the sample and can range from parts per million to percent level. The precision and accuracy of the assay results are essential to determine the economic viability of a mining project and are critical for effective decision-making. Therefore, it is essential to choose an appropriate assay method that meets the required level of sensitivity, selectivity, and precision for a particular sample. The determination of the silver content in concentrates can be challenging due to potential interferences from other elements present in the sample. Therefore, a thorough understanding of the sample matrix and appropriate sample preparation techniques are crucial to ensure accurate and reliable results.

To XERTEK, the best method for a particular sample depends on factors such as the expected silver content, the accuracy and the precision required.
A few of the silver assay methods for concentrates applied in Xertek are:

Fire Assay: This method is a popular choice for concentrates containing high levels of silver, above 300 ppm (parts per million or 100 g/t). The sample is mixed with lead and other reagents, and heated to high temperatures to separate the silver from other elements. The silver is then weighed to determine its concentration. The main advantage of this method is its high precision and accuracy.

Atomic Absorption Spectroscopy (AAS): This method involves vaporizing the sample and measuring the amount of light absorbed by the silver atoms in the sample. The amount of absorbed light is proportional to the concentration of silver in the sample. This method is fast, sensitive, and provides good accuracy and precision. The working range for this assay is from 10 g/t to 300 g/t

Inductively Coupled Plasma Mass Spectrometry (ICP-MS): This method involves atomizing the sample in a plasma torch and measuring the mass of individual silver atoms. This method is highly sensitive and provides accurate and precise results for a wide range of sample matrices. However, it is expensive and requires specialized equipment and expertise to operate. The working range for this technician is from 0.1 g to 10 g.