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Some simple knowledge of phosphorus powder

wallpapers News 2021-01-29
Phosphorus powder preparation method
The first is the transformation method (closed steel pot device). Put yellow phosphorus into a closed cast iron pot or steel pot, and keep it under 420℃ for several hours with gas or electric heating under the isolation of air to transform into red phosphorus. After cooling, the material in the transformation pot will be dark red to purple solid of. This fashion contains a small amount of yellow phosphorus. After being crushed, the yellow phosphorus is removed by boiling with a dilute caustic soda solution, and then sieved by wet method. It is filtered and washed in a rotary filter, and dried in a vacuum to obtain a red phosphorus product. The second is the conversion method (ball mill converter device). Before adding yellow phosphorus, the ball mill is replaced with inert gas. Before the temperature reaches 180-190°C, the converter is connected to the water seal, which takes about 2 hours to remove all water vapor.
 
Then, under sealed conditions, the yellow phosphorus was heated to 270°C for about 20 hours. The exothermic reaction began at this time, and the temperature rose to 290°C within 4 hours. When the exotherm ceases, reheat the temperature to 360°C, which lasts about 5 hours. The yellow phosphorus in red phosphorus is less than 0.1%, and it is removed by boiling with dilute caustic soda solution after cooling. Then 1% magnesium oxide was added to stabilize the red phosphorus. After filtering, washing with water, and vacuum drying, the red phosphorus product is obtained.
Properties of phosphor powder
Purple red or slightly brown amorphous powder, non-toxic, tasteless and shiny. Easy to absorb moisture. It can be heated to 416°C for sublimation and melted at 43kPa to 590°C. After gasification and condensation, white phosphorus is obtained. Insoluble in water and carbon disulfide, ether, ammonia, etc., slightly soluble in absolute ethanol. The stability is better than that of white phosphorous. It is stable at room temperature without phosphorescence and hard to react with oxygen. Fire above 200℃. It is mainly reducible, and it is a reducing agent when reacting with halogen and sulfur. 

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