| 摘要 |
A method of removing cadmium from raw phosphate material in an apparatus comprising a preheater section (2,13) a reactor section (3,4,5), a cooler section (7) and an exit gas cleaning section having a cadmium condenser (6,20,21), where the reactors (3,5) work in series and are formed as suspension reactors, or alternatively as a suspension reactor and a fluid-bed reactor, and where the treated raw phosphate in the first reactor having a short material retention time is suspended in a gas/fuel mixture and through a flash-process heated to a reaction temperature of 750 DEG -1050 DEG C. to be further heated subsequently in a reducing or neutral atmosphere in the second reactor which has a strongly reduced gas supply as compared with the first reactor and has at least three times as long a material retention time, by which the cadmium content is substantially expelled from the raw phosphate and carried away with the exit gas from the second reactor, while the cleaned phosphate is passed to the cooler section of the plant for further treatment.
|
