Continuous treatment of spent ion exchange resins - by treating resin in a column and periodically removing top fraction and introducing new fraction at the bottom

摘要

The top fraction is removed by a strong current of water and then the remaining resin in the column is displaced upwards through an equiv. distance by a short surge of liq e.g. at least 10 m3/m2/h. for about 60s. The new fraction pref. 12-15% of total vol. of resin, is then driven in under pressure. The top fraction passes from the regeneration column into a washing column and thence back to the fixation column where the ion exchange process occurs. The spent resin is drawn from the bottom of the fixation column. Where several treatment liqs. are required, a number of regeneration columns. in series of parallel as appropriate are used, the displacement of the top fraction taking place in the same manner. Any types of ion exchange resins can be treated with the appts. and method described, examples mentioned including demineralisation of boiler feed water and treatment of rinsing water used in electroplating. Moving the resin through the appts. in batches using short surges of liq. avoids fluidising the resin, which would lead to a reduction in regeneration efficiency.