Treating acid rinse water?
Treating acid rinse water?
(OP)
We evaporate about 200 gal a day of rinse water from an electropolish line. The untreated water has a ph of about 1. We have been adjusting ph to about 5 with caustic soda. it does not take to long to build up a sludge in the bottom of the evaporator that is a problem in a few ways.
Sludge built up to high in the last evaporator and caused the burn tube to buckle. $15,000-Pooffff!
My question. Is there another way to adjust ph that could at least create less sludge?
Thanks
Oak
Sludge built up to high in the last evaporator and caused the burn tube to buckle. $15,000-Pooffff!
My question. Is there another way to adjust ph that could at least create less sludge?
Thanks
Oak





RE: Treating acid rinse water?
Do some searching based on your requirements. Contact your supplier and see if they porvide soda ash instead of caustic soda.
Good Luck!!
Quote: "Its not what you know, its who you know"
Everythings a learning experience-Everything
RE: Treating acid rinse water?
RE: Treating acid rinse water?
Hope that helps.
RE: Treating acid rinse water?
We understand about the metals. We have delt with that with our waste hauler. There is not much but enough to classify the waste as hazardous.
I believe the sludge that we get is a result of the inert solid materials in the caustic soda. Our polishing process is not producing anywhere near the solid that we develop in the evaporator. I was hoping there would be a neutralizing agent that would not precipatate solids.
Thanks
Oak
RE: Treating acid rinse water?
I used to work in an electrochemical plant. It sounds like what you have is a mixed bag of 'cats and dogs' (thats what my boss used to call cations and anions). Metals (including alkali earths)plus caustic is a great recipe for sludge (precipitation). In fact this is intentionally done in the chlor-alkali industy.
You say you are developing solids in your evaporator...it sound like your evaporator is acting like a crystallizer ;)
Have you analyzed your sludge? This really should be the first thing that you do. A full ICP metals scan plus analysis for common anions (carbonates, sulphates, etc) would be a start. I would also include silica (silica tends to make any precipitation problem a bit more complicated).