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

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

-----

Rusting of bricks that have high iron content

Q. It has been suggested that Queenland bricks of light colour should be cleaned with HCl at 20:1 ratio due to the high iron content in the brick. Bricks are usually recommended at 10:1
My question is what pH level would be required to minimise rust stains in the bricks, and wouldn't they rust regardless due to rain water?

Gary Stephenson
- Sydney NSW Australia
June 11, 2012

A. Dear Gary,

Bricks have a high iron content, but they have iron salts and iron oxide, not iron metal. They don't rust anymore, as they are composed by some oxides. With hydrochloric acid you "clean" from the surface some of the excess ferric oxide.

At pH 2 you may be able to dissolve some iron oxide, but you must maintain that pH level through the immersion of the brick... A 1:10 is somehow a good choice, try 1:20 if the first is too aggressive.

The bricks will not rust with rainwater or any other rusting agent!

Hope you can solve your issue. Best regards,

Daniel Montañés
- Cañuelas, Buenos Aires, Argentina
September 19, 2012

(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: