A company is use Sulphuric Acid instead of HCl in Zinc Phospate coating process however, over time, iron oxide particles accumulate on the bottom of the bath and it makes is less usable. I am looking for a method to clean this accumulated particles. Is there any method of way to do this?
One possible method to remove iron oxide particles from the zinc phosphate bath is to use a filter press or paper to separate the sludge from the solution. This might help to improve the quality and performance of the bath.
Another possible method is to use an acid dipping step after the alkaline cleaning step to remove any tarnish or oxide films formed on the metal surface. This might help to prevent the accumulation of iron oxide particles in the bath.
A third possible method is to use phosphoric acid instead of sulfuric acid in the zinc phosphate coating process. Phosphoric acid is a rust converter that turns iron oxide into ferric phosphate, a black coating that can be easily scraped off. This might help reduce the amount of iron oxide particles in the bath and provide a protective layer on the metal surface.