Summary for chromate content in dichromate solution Discussion
Chromate content in dichromate solution is the thread’s focus keyphrase, and the practical advice given is to monitor the bath by titration. Abdul Baseer Siddiqui asked how to test chromate content after deposition on zinc-plated free-cutting steel seemed to disturb the bath balance and possibly contribute to white rust in a 96-hour salt spray test. Aimee Longacre first said a simple titration would likely be the easiest way to check chromium concentration, but asked for more details about the tank, temperature, metals, and the white rust appearance so she could be more specific. After Abdul clarified that the tank is 2 ft x 2 ft x 2 ft, runs at room temperature, and is used for cyanide zinc plating, Jose Morales added that he personally uses titrations to monitor all his tanks, from dichromate to nitric acid, calling it the simplest and highly effective method. No conflicting method was offered; the discussion points toward titration as the recommended approach.
Q. Initially we make a standard bath of dichromate solution with two ingredients water and chromate solution but after use the ratio of water and chromate solution getting disturb because of deposition of chromate on parts, my question is what is the method for the testing of chromate content in solution
If chromate poorly deposited than there is chance of white rust appearance
Abdul Baseer Siddiqui
– Karachi, Pakistan
December 22, 2011
December 28, 2011
I believe a simple titration could be the easiest way to test the chromium concentration, but before I make a suggestion, I would like some more information about the tank.
What are you using this tank for or what is its purpose? The tank you described kind of sounds like a hot seal tank but I am not entirely sure based on the information you provided.
How big is the tank and what is the tolerance on the concentration?
Does the tank operate at a certain temperature?
What types of metals are you processing through this tank?
Do you have a picture of the white rust on a part?
Any additional information you can provide, will provide you with better answers.
Aimee Longacre
– Savannah, Georgia, USA
January 3, 2012
Thanks Aimee for your reply
Answers of your questions are given below:
Q- How big is the tank and what is the tolerance on the
concentration?
A-Tank size is 2 ft x 2 ft x 2 ft and we have no any standard we are working only with experience (that is why I am asking this question)
Q- Does the tank operate at a certain temperature?
A-Room temperature
Q- What types of metals are you processing through this tank?
A-Free cutting steel with zinc plating (cyanide Zinc Plating)
Q- Do you have a picture of the white rust on a part?
A-It is normal white rust which
appears in Salt spray test (96 Hrs test)
Abdul Baseer
– Karachi, Pakistan
Personally, I use titrations to monitor all my tanks from Dichromate to Nitric acid. It is the simplest way to do it, not to mention is highly effective.
Jose Morales
– Berkeley, California, USA
February 11, 2012