What to consider with an ion exchanger / Safety instructions for ion exchangers
An ion exchanger is not a filter, but an exchanger and has some special features, which you will find summarized in the respective operating instructions for your application.
The most important rules and safety instructions for handling an ion exchanger must still be observed during planning and operation:
- Observe the respective product- and safety data sheets for the used ion exchangers.
- An ion exchanger is not a filter, but an exchanger, i.e. it always emits something, depending on its loading status and the selectivity series. The ion exchanger does also not absorb everything, but only according to its selectivity series. If the ion exchanger is operated beyond its capacity, i.e. if it is overrun, it releases unwanted substances that have already been bound back into the water in surges.
- The pH value and the temperature are important for an ion exchanger. As a rule, the inlet pH should be largely neutral (pH 6-9) (special applications may vary). In individal applications the pH value has a significant influence on the capacity and slip of the ion exchanger. If the pH is too low or too high, a regeneration can occur and all already bound substances are released again.
- The pre-loading of the ion exchanger influences the process, e.g. a pH-stable process is not possible with a selective ion exchanger in the Na form.
- When the capacity of an ion exchanger is exhausted, it is generally not replaced and discarded, but rather reprocessed via the (possibly external service) ion exchanger regeneration so that it is not overrun.
- The ion exchanger must not come into contact with oxidative substances (e.g. chemical cleaners), as this may cause an explosion in closed systems.
- Dry ion exchangers can generally still be used, but their volume increases abruptly when wetted with up to 400 bar pressure and can easily burst their containers.
- Dry ion exchangers burn very well.
- Ion exchanger balls on a smooth concrete floor are very slippery.
- Ion exchangers change their volume during operation between loading and regeneration. Therefore, do not fill an ion exchanger cartridge at “sight”.
- Ion exchangers react sensitively to particles, mineral oils and biology as well as to alkaline dissolved aluminum (Al), tin (Sn) and manganese (Mn). Therefore, avoid the entry as far as possible. Furthermore, avoid adding (semi-)concentrated acids and alkalis as well as alternative regeneration agents such as methanol, as these can trigger a regeneration.
- During operation, the pH value within a cartridge can shift by up to 4 points. This can lead to precipitation inside the cartridge or possibly to outgassing in the outlet of the cartridge.
- Ion exchangers are wear materials and have a typical service life of around 10 years for cation exchangers and 4-7 years for anion exchangers. During operation, individual resin balls can break (so-called ion exchanger grit or sludge) and pass through the outlet sieves (typically 0.2 mm). In some applications, a post-filtration of 10 µm is therefore required.
- Ion exchangers can build up electrical voltage fields. Therefore, make sure that you have the option of derivation in individual applications.
- Ion exchangers in the H+ form (e.g. cation exchangers in the mixed bed resin in a demineralization cartridge) can cause serious eye damage. Therefore, always ensure that you have the necessary PPE.
- Ion exchangers, especially strongly basic anion exchangers in the OH- form, give off an intense fishy odor or stench (trimethylamine). Make sure to remove it before use.
- Only send ion exchangers empty of residual water.
- Ion exchangers in a standing waterbed release substances that have already been bound due to osmotic effects. If you only operate an ion exchanger intermittently, secure this behavior in the system or discard the first bed volumes before taking them again.
- If the ion exchangers within an application have a predefined sequence (e.g. colour dots), do not mix them up under any circumstances, as this can result in undesirable chemical secondary reactions.
- Do not fill dry ion exchangers into ion exchanger cartridges or demineralization cartridges when changing the ion exchanger, as these can suddenly regain their original volume at up to 500 bar on contact with water and burst the ion exchanger cartridge even if there is sufficient freeboard. This is easily recognizable in the PE bags if the bag has collapsed. Otherwise, however, the exchangers are generally still usable.
- Ion exchanger cartridges should always be filled from below, as otherwise small air bubbles will form in the resin bed, which reduce the capacity and are difficult to remove during operation.
Depending on the industrial application, other aspects may be important for assessing the system design and operation and must be determined according to the application. It is therefore possible that other parameters are important for an individual application. Please contact our engineering team.