| 摘要 |
Ion exchange columns containing a layer of weak resin and a layer of strong resin are regenerated by passing partially spent regenerant through the column to regenerate the weak resin and then passing fresh regenerant through the column to regenerate the strong resin. Efficient regeneration is achieved in a downflow regeneration process and silica and calcium sulphate precipitation problems are reduced. In some cases, it is desirable to soak the strong resin in regenerant after the weak regenerant as been passed through the column in order to improve separation of the resins, shorten the total regeneration time and remove additional silica ions. The processes are preferably practiced on systems of three or more columns in which the columns are sequentially exhausted and regenerated, with at least two columns being regenerated in series. |
