PURPOSE: To produce odorless ammonium sulfate in improved yield and cost, by absorbing ammonia-containing coke oven gas in a part of ammonium sulfate mother liquor circulating in the system and returning the mother liquor after removing pyridine compound therefrom.
CONSTITUTION: Odorless crystal of ammonium sulfate obtained as a by-product in the coal carbonization process is produced by the following process. The crystal containing ammonium sulfate mother liquor is supplied from the crystal supplying tank 1 to the centrifugal separator 2 and the crystal is transferred to the drying stage by the belt conveyor 4. The filtrate is passed through the filtrate tank 3 to the mother liquor neutralizing column 5, in which ammonia in the coke oven gas is absorbed in the liquor to control the pH of the liquor to 7W8. The pH-controlled liquor is left stand in the separating tank 6 and separated into the upper layer consisting of a pyridine-rich oily substance 8 and the lower layer consisting of a debased mother liquor 9. The oily substance 8 is discharged from the system and the base-free mother liquor 9 is returned and recycled to the system. The ammonium sulfate produced by the above process is free from ill odor caused by tar base (especially pyridine) and has a pyridine-content of ≤60ppm.
| WO/2021/216600 | PROCESS TO PRODUCE AMMONIUM THIOSULFATE |
| JPS5281962 | METHOD OF TREATING ABSORPTION LIQUID FOR NITROGEN OXIDE |
IIZUKA YASUNOBU
NISHIMURA YOSHIHARU
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