Metal smelting generally contains two large content, namely mineral extraction and purification of metals.Mineral extraction and purification typically require high temperature heating, the process will use a lot of fuel, and the exhaust gas need to meet the national standards.The standard of testing will need gas analyzer.Similarly, in this process, because of the high temperature, general temperature measurement method cannot be used, then we will need special instruments such as infrared thermometer for the accuracy of temperature control.The content of purification material also need to use ultrasonic or other scientific testing method to determine.