Not seen this with titrated acid wash before.

[Julian]

Just finished an ASM batch that didn't go solid ... god I'm good!

The sequence of samples below are wash water ...



From left to right ...

1)  First wash with conc. sulfuric acid.  Mix about 45 mins settle about 120 mins.
2)  Second wash with added acetone. Mix about 45 mins settle about 120 mins.
3)  Third wash water only.  Mix about 45 mins settle about 120 mins.
4)   Fourth wash water only. Mix about 45 mins settle over night.
5)   Fifth wash water only.  Mix about 45 mins settle about 120 mins.

On doing a careful drain of the fifth wash this brown gunk came out as an intermediate layer between water and bio.  In the photo I separated the gunk as best I could and let it settle, resulting in bio and water dropping out.



Is this stuff what the soap turns into during the acid wash (can't remember the chemical name Paul called it)?  I can't say I've noticed it on previous batches and can't remember seeing it in the wash water until I left it overnight to separate.

[Head Womble]

For a start, well done on compleating an ASM batch.

It's interesting to see results of further washing after the acetone wash,
it's something I haven't done as yet and I'm quite surprised at the resulting colour of the wash water.

I have however had a smiler brown gunk layer from one of my acid wash batches (without acetone),
but from memory I think it was one I didn't settle overnight.

[Jamesrl]

Fank gawd for that, I thought I was the only one getting that crap at the split level only mines a little creamier.

[Julian]

It's not a good photo, Jim.  The gunk is a really dark brown.

[K.H]

First soap now a well known degreaser, proper little cottager industry

[Julian]

Weird thing is, I have my suspicions it only appeared after leaving the 4th wash to settle over night, coinciding with the yellowing colour change.

On early washes I tend not to drain every last drop of water, knowing I'm going to be sticking more back in, so I can be sure it's there from the first wash.

Wish I could remember the chemical name Paul gave it.

[Julian]

I'm trolling through the acid wash thread and found this photo I posted of an early acid wash I did ...


Compaired to the last batch ...


Only difference I can remember is leaving one wash to settle over night.

[jgs600]

i get that crap too when i acid wash

[Carrington]

Weird thing is, I have my suspicions it only appeared after leaving the 4th wash to settle over night, coinciding with the yellowing colour change.

On early washes I tend not to drain every last drop of water, knowing I'm going to be sticking more back in, so I can be sure it's there from the first wash.

Wish I could remember the chemical name Paul gave it.

Hi all
The chemical produced in nutralising is sodium sulphate  or potasium sulphate depending which base was used for the transeterification and sulphuric acid used in the nutralising.

If your using hydrochloric acid then you are producing
Sodium chloride or potasium chloride.


Paul

[Head Womble]

Weird thing is, I have my suspicions it only appeared after leaving the 4th wash to settle over night, coinciding with the yellowing colour change.

On early washes I tend not to drain every last drop of water, knowing I'm going to be sticking more back in, so I can be sure it's there from the first wash.

Wish I could remember the chemical name Paul gave it.

Hi all
The chemical produced in nutralising is sodium sulphate  or potasium sulphate depending which base was used for the transeterification and sulphuric acid used in the nutralising.

If your using hydrochloric acid then you are producing
Sodium chloride or potasium chloride.


Paul

Paul, can you verify something for me,
it was posted on another forum that when doing an acid wash the soaps were being converted back to FFA's,
now from what I've read this does seem to be the case if using iron exchange resins and if adding acid to bio without water,
but is it the same when adding acid and water ?

[Julian]

Weird thing is, I have my suspicions it only appeared after leaving the 4th wash to settle over night, coinciding with the yellowing colour change.

On early washes I tend not to drain every last drop of water, knowing I'm going to be sticking more back in, so I can be sure it's there from the first wash.

Wish I could remember the chemical name Paul gave it.

Hi all
The chemical produced in nutralising is sodium sulphate  or potasium sulphate depending which base was used for the transeterification and sulphuric acid used in the nutralising.

If your using hydrochloric acid then you are producing
Sodium chloride or potasium chloride.


Paul

Thanks Paul.

So if this gunk is the product of converting soaps to, in my case, to sodium sulphate, am I right in saying it should be present, to a greater or lesser extent (depending on the titration value), each time we acid wash.

I ask because I'm not convinced I'm getting it each time I acid wash.  That said I haven't specifically looked for it in the past.

I assume the long settling period (over night in this case) allows it to settle where previously it may have remained in suspension.  Have you any idea why the wash water would turn yellow for the latter washes?

[Julian]

jgs600,  Jim and Mark ...


Do you get the gunk every time?

If not, what circumstances make it appear?

[K.H]

What about testing the pH of the wash water?

[Julian]

What about testing the pH of the wash water?

To see if it changes as it goes yellow?

[Head Womble]

I've only seen it once, but I do tend to just look for the colour change in my flexable pipe.

I recently emptied my settling / bio storage drum (my takeoff leaves 25L in the bottom of the drum) and didn't see any at the bottom, as I still have that 25L sat in a drum I'll see if anything has settled out.