Aluminum Fluoride AlF3 dry production process
1. Crude acid drying method: The gas generated after the high temperature reaction of sulfuric acid and fluorite enters the fluidized bed after rough washing, and reacts with the dried aluminum hydroxide to generate Aluminum Fluoride AlF3 at high temperature. Because the hydrogen fluoride content after rough washing is about 96% and the impurities are high, the impurities of the Aluminum Fluoride AlF3 product are relatively high; especially without desiliconization, the silicon dioxide content of the Aluminum Fluoride AlF3 product reaches 0.25%. These impurities will affect the quality of electrolytic aluminum and add electricity consumption during electrolysis.
2. Fine acid dry method: the gas generated after the high-temperature reaction of sulfuric acid and fluorite enters the evaporator after rough washing, freezing, degassing, and rectification. At this time, the content of hydrogen fluoride is usually 99.5%; % hydrogen fluoride gas enters the fluidized bed and reacts with wet aluminum hydroxide to generate Aluminum Fluoride AlF3 at high temperature. Because of the high purity of hydrogen fluoride, the aluminum Fluoride AlF3 produced in this way has good quality and low impurities, especially the content of silicon dioxide is only 0.02%, and the content of phosphorus pentoxide is only 0.007%, which is very beneficial to the production of electrolytic aluminum.