| 摘要 |
PURPOSE:To reuse an aqueous solution of phosphate containing Cr as a solution for producing single crystal of KH2PO4, by bringing the aqueous solution into contact with a specific chelate resin so that Cr is adsorbed and removed. CONSTITUTION:A resin (e.g., PVC, or polyacrylonitrile) having an amine reactive group such as halogen atom, nitrile group, epoxy group, etc., any shape and >=50 polymerization degree is reacted with a chelate-forming resin (e.g. diethylenetriamine) consisting of a polyalkylenepolyamine (derivative), to give a chelate resin containing a polyalkylenepolyamino group. Then, an aqueous solution of phosphate containing Cr (aqueous solution of KH2PO4) with high concentration of with the chelate resin, at <=90 deg.C at 50-10,000 volume times solution passing ratio, brought into contact with the resin, Cr is adsorbed and removed, the aqueous solution of phosphate is purified and reused. On the other hand, the chelate resin is brought into contact with an eluent (e.g., hydrochloric acid), eluted, optionally treated with an alkali aqueous solution, washed with water and reused. |
