| 摘要 |
PROBLEM TO BE SOLVED: To recover gypsum with reduced moisture content. SOLUTION: A dewatering chamber 7 is provided at a lower side of the carrying face of a belt filter 18 circulatably stretched between rollers 17. A gypsum slurry supply part 20 is provided above the upstream end in the carrying direction of the belt filter 18, a cake washing apparatus 8 is provided above an intermediate part, and a dewatering zone 15 is provided above a downstream position. The dewatering zone 15 is provided with a plurality of infrared heaters 16 disposed in the carrying direction, and a fan 24 sending air to the surface of gypsum cake 5b positioned under the heaters 16. Mother liquid 21 in gypsum slurry 5 supplied to the belt filter 18 from the gypsum slurry supply part 20 is sucked into the dewatering chamber 7 to form the gypsum cake 5b, and contained salt is removed by a cake washing device 8. Then, the gypsum cake 5b is irradiated with infrared ray 22 from the infrared heaters 16 in the dewatering zone 15 to directly heat and evaporate moisture in the whole gypsum cake 5b, to reduce total moisture content. COPYRIGHT: (C)2006,JPO&NCIPI
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