The drying process requires a large amount of heat energy. In order to save energy, some materials with high moisture content, suspensions or solutions containing solid substances are generally first mechanically dehydrated or heated to evaporate, and then dried in a dryer to obtain a dry solid.
In the drying process, heat and mass (moisture) transfer must be completed at the same time to ensure that the moisture partial pressure (concentration) of the surface of the material is higher than the moisture partial pressure in the external space to ensure that the heat source temperature is higher than the material temperature.
Heat is transferred from the high-temperature heat source to the wet material in various ways, so that the surface of the material is vaporized and vaporized to the external space, so that the difference in moisture content occurs on the surface and inside of the material. The internal moisture distribution diffuses and vaporizes to the surface, so that the moisture content of the material is continuously reduced, and the overall drying of the material is gradually completed.
The rate of drying of the material depends on the rate of surface vaporization and the rate of diffusion of the internal moisture. Generally, the drying rate in the early stage of drying is controlled by the surface vaporization rate; then, as long as the external conditions of drying are constant, the drying rate and surface temperature of the material remain stable. This stage is called the constant-speed drying stage; when the moisture content of the material is reduced to a certain To the extent that the rate of diffusion of the internal moisture to the surface decreases and is less than the surface vaporization rate, the drying rate is mainly determined by the internal diffusion rate and decreases with the decrease of the moisture content. This stage is called the slow-down drying stage.
Ferro Tungsten belongs to ferroalloy series (containing tungsten: 70%-80%), an alloy composed of tungsten and iron, used as an alloy additive for steelmaking. The commonly used tungsten iron is tungsten containing 70% and 80%.
Tungsten and iron are the main components of the iron alloy. It also contains manganese, silicon, Carbon, phosphorus, sulfur, copper, tin and other impurities, and is an alloying agent for steelmaking. According to different amounts of tungsten, the tungsten and iron are divided into: FeW75 (including W70% ~ 80%, C ≤ 0.20%, P ≤ 0.04%, S ≤ 0.08%, Si ≤ 0.5%, Mn ≤ 0.25%) and FeW80 (including W75.0%~85.0%, C≤0.20%, P≤O.04%, S≤0.08%, Si≤0.7% and Mn≤0.25%).
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