The authoritative public forum
  for Metal Finishing since 1989
-----

LOOKING FOR A WAY TO CLEAN AND FILTER RINSE WATER

GREETINGS:

I WAS WONDERING IF ANY ONE OUT THERE KNOWS OF A WAY OR KNOWS OF A PRODUCT AVAILABLE TO FILTER RINSE WATER FROM A HARD CHROMIUM PLATING OPERATION. CURRENTLY HAVE 4 RINSE AFTER PLATING TANKS ON EACH OF THREE PLATING LINES AND AM LOOKING FOR A WAY TO FILTER THE RINSE WATER TO KEEP IT CLEAN LOOKING AND "FRESH". CURRENTLY BEING CLEANED BY EMPTYING OUT THE ENTIRE CONTENTS OF THE RINSE TANK AND HAVING TO DISPOSE OF IT AND REFILLING WITH CLEAN DE-IONIZED WATER. JUST WONDER IF THERE IS A FILTER SYSTEM BEING MARKETED OUT THERE THAT WOULD MAKE THIS PROCESS MUCH EASIER WITHOUT ALL THE WASTE GENERATED. THANKS FOR ANY HELP OR COMMENTS GIVEN.

GARY LAPE JR.
- GREENWOOD, INDIANA, U.S.A.
2003

---

That all depends on how much money you want to spend. Are these rinses stagnant or counter flowed? If not counter flowed, modify them. See Ted's Article on rinsing in the Metal Finishing Guidebook. You can get to it from the main page. Do you use any of the chrome water from the first tank for make up of the plating tank? For some help, you could filter the first tank with fiberglass filters in an appropriate plastic filter housing and pump. Polypropylene filters will only last a week or so then break down causing a lot of trivalent and a yellow scum.

James Watts
- Navarre, Florida
2003

---

Most hard chromium platers try to return the rinsewater to the plating tank to replace evaporation. With as many rinses as you have, most of it should go back in. If not, then supplemental evaporation can close the loop. The only problem with this approach is the build-up of contaminants, and this is usually handled by a purification system. There are both ion exchange and membrane electrolysis types of systems on the market that can remove iron and other impurities.

Lyle Kirman
consultant - Cleveland Heights, Ohio
2003