| 摘要 |
PROBLEM TO BE SOLVED: To accelerate the sedimentation of a solid when the solid is separated from a liquid to realize the rapid solid/liquid separation by first adding a polymer flocculating agent to water while it is stirred and keeping this state as it is under a non-stirring condition for a specified time. SOLUTION: In the treatment of a waste liquid containing oil or a flocculation treatment such as the separation of a bauxite residue or the like in a manufacturing process for the Bayer process alumina or the like, a first step to add the polymer flocculating agent to water while it is stirred and a second step to keep this state as it is under a non-stirring condition for 20-240 min. are performed. The polymer flocculating agent to be used is preferably an anionic polymer flocculating agent such as a polyacrylic soda, the partially hydrolytic product of polyacrylamide or a copolymer of acrylamide and a acrylate solt. For the addition amount of the polymer flocculating agent, it may be properly selected depending upon the molecular weight of the polymer flocculating agent, ionic properties, a treated water intended for or the like. In the case of the anionic polymer flocculating agent, its addition amount is normally to be decided so that an about 0.5-1% aqueous solution can be obtained.
|
