Non-Chemical Incineration/pyrolysis question

[bswartzwelder]

When incinerating/pyrolyzing, does it make any difference if I mix filter papers in with the chips I'll be pyrolyzing or should the items be kept separate? I don't see how mixing items to be incinerated/pyrolyzed would make any difference but just wanted to make sure before I screw something up. To me, it would be like eating cake and ice cream, it's all going to the same place in the end.

 

[patnor1011]

I do not understand. You need to separate incinerated ash from chips from material you want to leach. If you incinerate IC with papers how do you catch that super fine powder from incinerated filter papers.
If you intend to leach incinerated material without reducing it to at least one tenth you are going to lose values.

 

[bswartzwelder]

Now, I'm confused. What I had intended on doing was pyrolyze the chips and filter papers in an oxygen deprived atmosphere. Then incinerate what was left in the same vessel in the presence of atmospheric air. After having done this, separate out any pins or metals left behind. Process the metals according to their composition (electrolytic cell where there is no solder, boiling HCl OR hot Nitric to get rid of solder). Pan the leftover ashes and then put into poorman's AR or HCl/Chlorox for the initial treatment, followed by true AR dissolution in AR followed by an Oxalic Acid drop. I can see no reason to exclude the filter papers from the pyrolysis/incineration, nor can I see any reason why I would need to do them separately. Am I wrong?

 

[rickbb]

Any PM trapped in the filter paper may be too fine to fall out with gold plated parts and get washed away with the ash. Most people float/wash the ash off the plated metal parts after pyro/incineration. Doing that with filter paper may lose the values in them.

 

[maynman1751]

The values from the incinerated filters would be lost in the ash. There would be no way to separate your filter values from the regular ashes. Do your filters separately.

 

[FrugalRefiner]

Pan the leftover ashes and then put into poorman's AR or HCl/Chlorox for the initial treatment, followed by true AR dissolution in AR followed by an Oxalic Acid drop.

Bert, as the others have said, the filters will be a problem in that panning step. The gold from the chips will be in the form of bonding wires. As small as these are, they are probably hundreds or perhaps thousands of times larger that the gold trapped in your filters. During panning, the wires will settle to the bottom of your pan, but the tiny bits of gold from your filters will likely float away with the ash.

With chips, there is a lot of ash left after incineration, so it is in your best interest to reduce the quantity of ash through panning prior to chemical treatment. With the filters, there is very little ash left so it can be taken directly to the acid of your choice.

Hope that makes sense.

Dave

 

[bswartzwelder]

Thanks to all who have responded. I wasn't thinking about the size of the particles of gold in my filter papers as being that small and the differences in the size of the ash from the chips and paper. The filter paper I had in mind has a lot of larger pieces of gold which were trapped after I ran my used AP solution through the filter paper. The gold there is highly visible, and much of it is fairly large, but it is stuck tightly to the filter paper.

My plans have changed, and I will soak all my filter papers in either poorman's AR or most likely, HCl/Chlorox to put the gold into solution. Then I can drop it with SMB. The filter papers will be sprayed down with good old H2O to wash out and remaining chemicals which may hold PM's, then be dried and incinerated at a later date (no need for pyrolization).

When I mentioned pyrolization in my first post, I was just planning on making things as simple as possible by throwing everything together into one process. I knew there would not be enough toxic gasses generated by the filter paper to warrant pyrolysis, but in actuality, either the pyrolysis or the incineration would have generated enough heat to turn the papers to ash.

Again, thank you for not letting me make a mistake where I could have lost exactly what I was trying to keep.

 

[patnor1011]

I think you complicate things. Why additional steps leaching filters, washing, saving for later.
Simply incinerate them and process ash in AR.
Job done.

 

[Geo]

i hold my filters until i have at least a garbage bag full dry. ive only had to process my filters twice so far.

 

[butcher]

carbon (even from burning the filter paper) can cause problems with PGM's.

 

[bswartzwelder]

Patnor,

I am not trying to complicate things, just the opposite. If it would have been feasible to process the filter papers with the chips, it would have solved two problems in one process. Since that approach looks like it could introduce problems of losing values, I will not be using it.

I do have some very large filter papers which have a huge amount of gold on them. I would guess in the range of a gram or maybe more. I also have some filter papers where the gold was in the form of a solution that had dried when the filter paper dried. Probably not enough there to collect unless I have a trash bag full of the papers. The idea of using a leech is to prevent valuables in the form of micron size gold particles from being blown away in the smoke produced by incineration. You have to use a leech on the ashes anyway, why not use it up front and collect your values before the ashes get swept away in the wind?

 

[butcher]

Just thoughts on leaching filter paper instead of incinerating them first:
Remaining paper would hold some liquid containing value.
If tin (or base metals) could cause problems later.
Silver would not be leached with gold, although nitric could be used to leach silver, but tin again can give problems.
Filters can contain organics like bugs...

Values from filter papers could be collected in a furnace melt, possibly with other values being collected in a melt with a metal collector and flux.