Graphite crucible is often used in the production of metal and semiconductor materials. In order to make metal and semiconductor materials reach a certain purity and reduce the amount of impurities, graphite powder with high carbon content and low impurities is required. At this time, it is necessary to remove impurities from graphite powder during processing. Many customers don’t know how to deal with the impurities in graphite powder. Today, Furuite Graphite Editor will talk about the tips for removing impurities in graphite powder in detail:
When producing graphite powder, we should strictly control the content of impurities from the selection of raw materials, choose raw materials with low ash content, and prevent the increase of impurities in the process of processing graphite powder. The oxides of many impurity elements are constantly decomposed and evaporated at high temperature, thus ensuring the purity of the produced graphite powder.
When producing general graphitized products, the furnace core temperature reaches about 2300℃ and the residual impurity content is about 0.1%-0.3%. If the furnace core temperature is raised to 2500-3000℃, the content of residual impurities will be greatly reduced. When producing graphite powder products, petroleum coke with low ash content is usually used as resistance material and insulation material.
Even if the graphitization temperature is simply increased to 2800℃, some impurities are still difficult to remove. Some companies use methods such as shrinking furnace core and increasing current density to extract graphite powder, which reduces the output of graphite powder furnace and increases the power consumption. Therefore, when the temperature of graphite powder furnace reaches 1800℃, purified gas, such as chlorine, freon and other chlorides and fluorides, is introduced, and it continues to be added for several hours after the power failure. This is to prevent the vaporized impurities from diffusing into the furnace in the opposite direction, and to expel the remaining purified gas from the pores of graphite powder by introducing some nitrogen.
Post time: Jan-06-2023