INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

sludge formed while attempting to neutralise caustic

sludge formed while attempting to neutralise caustic

(OP)
while washing plastic scrap grinding I tried to neutralize the caustic present in it with HCl.The addition of HCl caused a grey sludge which would float to the top leaving clear water below.I had thought that the resulting NaCl would be soluble in water and not create a problem but the floating sludge is problematic.When the water turns basic the sludge mixes with the water again.Has any one faced any similar difficulties? What is this floating sludge? How does one handle it?

RE: sludge formed while attempting to neutralise caustic

Would suspect it is oil, but with knowing so little, somewhat hard to say. You have not supplied any information on the water quality, plastic, or why the plastic scrap has sodium hydroxide or anything else mixed into it. If you drop the pH, if there is emulsified oil present, it will break the emulsion and cause the oil to release.

RE: sludge formed while attempting to neutralise caustic

(OP)
The Plastic grinding was of bottle cap coming from a plant which crushes and washes and reclaims PET from PET bottles.The caustic was a remnant.I was trying to reclaim the plastic.The water used was tap water.The sludge did not seem to be oily.

RE: sludge formed while attempting to neutralise caustic

Hi there,

You might want to consider dissolved air flotation to remove this unsettling sludge. Dissolved air helps float the sludge so that the floating sludge can be removed from the surface as scum by a mechanical skimmer.

Cheers,
Wan

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close