Time:2023.08.03Browse:1
The flotation method is one of the conventional mineral purification methods that consumes less energy and reagents, and has lower costs. This is a major advantage of the flotation method for purifying graphite. However, when using the flotation method to purify graphite, it can only achieve a limited improvement in the grade of graphite. For flake graphite, using multi-stage grinding not only cannot completely dissociate its monomers, but also is not conducive to protecting the large flakes of graphite. Therefore, using flotation to further improve the graphite grade is not economical or scientific. To obtain high carbon graphite with a carbon content of over 99%, it is necessary to use chemical methods to purify the graphite.
(1) Chlorination roasting method
The low roasting temperature and low chlorine consumption of the chlorination roasting method greatly reduce the production cost of graphite. At the same time, the carbon content of graphite products is equivalent to that after treatment with hydrofluoric acid method. Compared to the chlorination roasting method, the recovery rate is higher. However, due to the toxicity and strong corrosiveness of chlorine gas, equipment operation requirements are high, strict sealing is required, and tail gas must be properly treated, which to some extent limits its promotion and application.
(2) Alkali acid purification method
The carbon content of graphite purified by alkaline acid method can reach over 99%, which has the characteristics of low one-time investment, high product grade, strong process adaptability, and also has the advantages of conventional equipment and strong universality (except for graphite, many non-metallic ores can be purified by alkaline acid method). Alkali acid method is a widely used method in China today, but its disadvantages include high energy consumption, long reaction time, large graphite loss, and severe wastewater pollution.