No cost, no registration, no passwords -- just aloha, fun & authoritative answers
(as an eBay Partner & Amazon Affiliate we earn from qualifying purchases)

Where the
world gathers for metal finishing
Q&As since 1989

-----

Demineralizer

Please explain why cation exchanger is located before anion exchanger and whether they can be swapped.

Regards,

Abdulghani
- Jubail, Saudi Arabia
2002

You do the cation exchange first because the anions are more universally soluble than the cations. If the sulphate or nitrate or chloride was soluble in the original incoming stream it will probably remain soluble when you replace the cations with hydrogen, acidifying the stream. If you remove the anions first, the cations are quite likely to precipitate as an hydroxide and make a mess.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2002

(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories: