Infrared carbon sulfur instrument (with high frequency combustion furnace) is suitable for burning steel, alloys, non-ferrous metals, cement, ore, glass, ceramics and other materials, and can quickly and accurately determine the content of C and S in materials. When the high-frequency burner works, it is necessary to add a flux to the combustion sample to make it fully burn. The selected flux should be a conductive and magnetically permeable material. It must be an exothermic reaction during the combustion process. It forms a fluid when the sample is oxidized and melted. The volatiles do not adsorb carbon dioxide and sulfur dioxide. The carbon and sulfur content of the flux should be low, the carbon should be less than 0.0008%, and the sulfur should be less than 0.0003%. When the flux and the sample are oxidized and melted, there is no erosion effect on the crucible to prevent the crucible from cracking and leaking during the combustion process.
The main role of the flux is to provide the sample with oxidation heat, change the melting characteristics, stabilize the combustion, and cover the sample to prevent splashing. The proper selection of the flux, the proper amount will accelerate the sample's oxidation and melting, and can improve the carbon and sulfur release rate and measurement accuracy.
At present, most of the infrared carbon and sulfur analyzers are high-frequency induction furnaces. When measured by the combustion method, the applicable metal fluxes are: tungsten, tin, pure iron and copper. The temperature of the high-frequency furnace is between 1600 ° C and 2000 ° C. The flux can be used in the following methods: pure tungsten particles, tungsten + tin, tungsten + pure iron, tungsten + tin + pure iron. The last three are mostly used for melting and refractory. Metal and non-metal samples.
Tungsten is the most difficult metal to melt. It has a melting point of 3380 ° C and is easily oxidized. Tungsten begins to oxidize and emit a lot of heat when oxygen is passed at 650 ° C. The infrared carbon and sulfur analyzer
has the characteristics of high instantaneous heating value and fast reaction speed, so tungsten particles are needed as additives. Tungsten particles are not only used for fluxing, but also for multiple functions such as heating, adjusting the acidity and alkalinity of the medium, stirring, catalysis, flame stabilization, and anti-interference. Tungsten particles in the infrared carbon and sulfur analyzer play such multiple analysis functions. Generally, tungsten particles and tin particles are used in the instrument
in combination. The main role of tin is to promote the flux. The infrared carbon and sulfur analyzer reduces the effect of insufficient flux of tungsten.
When tungsten + tin, copper, and tin flux are used, the measured value of carbon is close to the standard value and the accuracy is high. The effect of copper flux is the best. Therefore, when measuring carbon, all three fluxes are suitable. With tungsten + tin mixed flux, the measured value of sulfur is close to the standard. When copper or tin flux is used, the measured value of sulfur is significantly lower, so copper and tin flux are not suitable for measuring sulfur value.
Tungsten flux has high heating value, low oxidation temperature (650 ° C), and good melting state, so that the carbon and sulfur in the sample are fully oxidized and released completely. The obtained results have the smallest deviation compared with the standard value and high accuracy. It can be said that tungsten is a high frequency induction Furnace good flux.