Nitric Acid Based Solder Strip

Thread from IPC's ComplianceNet

Date: Fri, 24 Jul 1998 15:06:58 –0400
From: "Christopher J. Ford"
Organization: Massachusetts Toxics Use Reduction Institute
Subject: Nitric Acid based Solder Strip

Hi All:

I have a company that has asked me to find some information on disposal issues for nitric acid based solder strip. The TSDF to which they ship has found that the particular solder strip formulation they use contains ammonia, which is problematic for them to treat. The company would like to know if anyone else has run into this situation, and if so, what was the best treatment or disposal option.

Thanks,

Chris Ford

Date: Fri, 24 Jul 1998 14:57:08 +0000
Reply-To: brad@afiweb.com
Sender: ComplianceNet Mail Forum
Comments: Authenticated sender is
From: Brad Hoium
Organization: AFI
Subject: Re: Nitric Acid based Solder Strip
In-Reply-To: <35B8DB52.1B2E2A50@uml.edu>

The treatment facility that we use explained to me that ammonia is a by-product produced in the stripping process when using nitric acid based stripper. I think they said it was normal for up to around 1000 parts per million to be formed, although I do not remember the exactly what it was.

The level of ammonia in our spent stripper though is not enough to cause the treatment facility any difficulty.

Brad Hoium
Advanced Flex, Inc.

Date: Fri, 24 Jul 1998 18:11:23 –0400
Reply-To: "ComplianceNet E-Mail Forum." , lwilmot@HADCO.COM
Sender: ComplianceNet Mail Forum
From: Lee Wilmot
Subject: Re: Nitric Acid based Solder Strip
X-To: "Christopher J. Ford" Christopher_Ford@UML.EDU

Chris,

As far as I know, there are two types of solder strippers - either nitric acid based, or ammonium bifluoride (ABF) based. We use both types in different divisions. Both types are treated on-site. Nitric can be simply pH adjusted but ABF requires treatment for chelated metals. If you have a tight lead limit and don't have a good chelate treatment, Pb in your WW discharge can be an issue.

One of our divisions which used to use ABF recycled it off-site at Metal Recovery Industries,Inc (MRII) in Hamiltion, Ontario. Yes we had to obtain prior approval from regional EPA office, and then dual manifest each shipment. Switch to nitric based stripper allowed both on-site neutralization and eliminated recycling paperwork.

I'm confused by your inquiry saying that he's using a nitric stripper and TSDF saying they have problem treating ammonia? To my knowledge, nitric and ABF are not mixed.

Lee Wilmot
HADCO Corp

Date: Mon, 27 Jul 1998 09:07:56 –0400
Reply-To: "ComplianceNet E-Mail Forum." , "Christopher J. Ford"
Sender: ComplianceNet Mail Forum
From: "Christopher J. Ford"
Organization: Massachusetts Toxics Use Reduction Institute
Subject: Re: Nitric Acid based Solder Strip
X-To: lwilmot@HADCO.COM>

Hi Lee:

Thanks for your answer. We are confused as to the presence of ammonia in the nitric-based solder strip as well. After some pointed inquiries, the manufacturer has told us that there is a complexed ammonia salt in the solder strip. Apparently, when the pH is raised at the TSDF, there is enough free ammonia to cause a problem with their system (the company has had several tests performed, and ammonia concentration results range from 1,000 ppm to 5,000 ppm).

So, if anyone else has seen this situation at their TSDF, we would appreciate any additional information regarding how it was handled with them, or if another TSDF was found for which the ammonia did not represent a problem.

Again, thanks.

Chris