Abstract:The traditional silver ingot casting process had some problems such as high labor intensity, high risk coefficient, unstable quality of silver ingot products, and large silver loss, so a new automatic production line for silver ingots using nitrogen to protect molten silver was introduced. By introducing its principle, structure, process flow and advantages, it can be seen that as the new automatic production line of silver ingot used nitrogen to isolate the contact between silver and oxygen, and the whole process was controlled by PLC, it had the characteristics of automatic, green and environmental protection, no casting loss, and few defects in silver ingot.