| 摘要 |
In the treatment of liq. effluent from metal cleaning (pickling) processes, (a) the water is passed over a cation exchange resin, (b) the water from (a) is passed over an anion exchange resin, (c) the purified water is passed to the washing installation, and (d) the cation exchange resin from stage (a) is regenerated by elution with a strong mineral acid moving in the opposite direction to that of stage (a). The process is simple and economical to carry out. It may be varied in order to comply with changes in effluent regulations. In opt. further stages (e) the anion exchange resin is eluted with a strong soluble base, such as an alkaline hydroxide or ammonia; (f) the eluate from (e) is passed over a cation exchange resin to regenerate the acid used in the pickling process; and (g) the cation exchange resin from stage (f) is regenerated using sulphuric, nitric, or phosphoric acid which is circulated in the opposite direction to that used in stage (e). If this last stage is carried out an effluent is obtd. contg. fertiliser salts such as ammonium and potassium nitrate, ammonium and potassium phosphate and ammonium sulphate. |
