Time：2023.11.07Browse：1
The chlorination roasting method involves adding a certain amount of reducing agent to graphite powder, roasting it at a certain temperature and under a specific atmosphere, and then introducing chlorine gas for a chemical reaction to transform valuable metals in the material into chlorides and complexes with lower melting and boiling points in the gas phase or condensed phase, and escape them, thereby separating them from their remaining components and achieving the goal of purifying graphite.
Impurities in graphite can be decomposed into simple oxides such as SiO2, Al2O3, Fe2O3, CaO, MgO, etc. under the action of reducing agents after being heated at high temperatures. These oxides have higher melting and boiling points, as shown in Table 1, while their chlorides or metal complexes formed with other trivalent metal chlorides (such as CaFeCl4, NaAlCl4, KMgCl3, etc.) have lower melting and boiling points, as shown in Table 2. The vaporization and escape of these chlorides improve the purity of graphite.
The metal complex discharged in a gaseous state quickly becomes a condensed phase due to temperature reduction, and this characteristic can be used for the treatment of escaped waste gas.
Test steps: Mix the graphite sample with a certain proportion of reducing agent coke and load it into a corundum tube. Install a ceramic sieve plate and ceramic ball at the lower part of the corundum tube to block the falling of the graphite material column, and seal both ends of the corundum tube without air leakage. Place the corundum tube in the furnace for heating, and first inject nitrogen to drive out the air inside the tube to prevent graphite oxidation at high temperatures. When the set temperature is reached, turn off the nitrogen gas and start introducing chlorine gas. The volatile chlorides or complexes generated by the chlorination reaction are filtered and discharged into the atmosphere through a condensate bottle. After a certain period of time in the chlorination reaction, turn off the chlorine gas and then inject nitrogen to drive out the residual chlorine gas and chloride gas.
The chlorination roasting method has the advantages of energy conservation, high purification efficiency (>98%), and high recovery rate. The toxicity, severe corrosiveness, and severe environmental pollution of chlorine gas to some extent limit the promotion and application of chlorination roasting technology. Of course, this process is difficult to produce graphite with extreme purity, and the process system is not stable enough, which also affects the application of the chlorination method in actual production. This method still needs further improvement and improvement.
Haifeiling owns domestic advanced technology, equipment and high-level R D team, and is committed to creating well-known brand trademarks of Haifeiling products
4008-168-001
2023-09-20
