To highly efficiently recover an adipic acid component and an ammonium component by adding a calcium source to an ammonium adipate-containing waste soln. to make the waste soln. weak alkaline and separating generated ammonia gas while subjecting calcium adipate crystallized in a reaction soln. to solid-liquid separation.
Waste solns. containing ammonium adipate are collected in waste soln. storage tanks 1, 2 to be respectively taken out in a predetermined ratio. The taken-out waste solns. are supplied to an RO apparatus 3 to concentrate ammonium adipate and the conc. ammonium adipate waste soln. is guided to a calcium adipate forming tank 4. Cream of lime obtained by emulsifying calcium hydroxide by industrial water or the like is added to the tank 4 and air is blown in the tank 4 from the lower part thereof. By this treatment, ammonia is separated and recovered and calcium adipate hydrate is precipitated in the tank 4. The overflow slurry is sent to a sedimentation tank 5 to be subjected to sedimentation treatment and calcium adipate is separated and recovered from a condensing part by a centrifugal separator 6.
SUGIYAMA NOBORU
EGAMI YASUSHI
OZAWA HIROSHI
NIPPON CHIKUDENKI KOGYO KK
NIKKEI SANGYO KK