Removing resin from rare ceramic CPU base.

[MvK]

Dear members,

I have tried to process some weird telecom boards. I removed the CPU-like things. They are white ceramics, with gold tracings on them connecting up to 16 smaller CPU per ceramic.

I have already processed the smaller CPU. I twisted them off with a small wrench. What is left is the base with alot of gold tracings.

The problem im having right now, the ceramics are covered in 2 types (grey and invisible) resin. It looks and feels like silicon, but its super heat resistant.

When i torched a small batch of lids from the smaller CPU with my MAPP torch to try to burn the resin off, it came off in a white ash, but it made the lids hydrophobic. I just put them in nitric to disolve the base metals, but the acid didnt catch the lids. When i scooped them up from the bottom they were bone dry. Eventually i saved most of the batch by using brake cleaner...
The next batch i did without burning to avoid the trouble with the silicones(?) mixed with Kovar.

So now i want to recover the gold from the bases, but AR does not catch the gold under the resin so that stuff has got to go. I have tried household solvents like white spirit, brake cleaner etc but the layer is just too thick. I didnt try industrial stuff yet because i have to clue what this material is.

Any tips to remove the resin, or how to make this work without burning? I have alot of material to process, so i hope someone worked with this stuff before..

Thanks!

Mia

 

[war_child]

Hello there. I can't offer any help with your dilemma, but I can offer you a warning: I don't know what the material you are working with is made out of, but red flags come up whenever I hear about or see anything that resembles a "white ceramic substance" in E-waste/ gold recovery. You should make sure that white substance is NOT beryllium or beryllium oxide. I cannot identify it for you, because I just don't know what to look for, but I urge you to search beryllium in the search bar above before you proceed, or even handle it any further. From what I gather, it's some pretty nasty stuff. You certainly don't want to breathe any of it in.

 

[eaglekeeper]

Hello there. I can't offer any help with your dilemma, but I can offer you a warning: I don't know what the material you are working with is made out of, but red flags come up whenever I hear about or see anything that resembles a "white ceramic substance" in E-waste/ gold recovery. You should make sure that white substance is NOT beryllium or beryllium oxide. I cannot identify it for you, because I just don't know what to look for, but I urge you to search beryllium in the search bar above before you proceed, or even handle it any further. From what I gather, it's some pretty nasty stuff. You certainly don't want to breathe any of it in.

War_child warning is correct, there's a good possibility those maybe BeO. Do not crush or incinerate these unless you know for sure they are not.

As far as the coating, A warm concentrated sodium hydroxide solution may work, but I don't know how that would react with BeO. I hope someone with more experience the BeO will chime in on this topic.

Nice looking material though...

 

[nickrpotts]

I believe these are either thin or thick film hybrids, which is likely an alumina base. The traces are then co-fired precious metal and glass loaded inks. These are in simple terms a printed circuit board however which a much higher thermal characteristics than traditional PCB. Likely 800'c+ cure.

 

[MvK]

Hello there. I can't offer any help with your dilemma, but I can offer you a warning: I don't know what the material you are working with is made out of, but red flags come up whenever I hear about or see anything that resembles a "white ceramic substance" in E-waste/ gold recovery. You should make sure that white substance is NOT beryllium or beryllium oxide. I cannot identify it for you, because I just don't know what to look for, but I urge you to search beryllium in the search bar above before you proceed, or even handle it any further. From what I gather, it's some pretty nasty stuff. You certainly don't want to breathe any of it in.

Thank you for the warning, i will definitly abandon both inceneration and crushing methods just to be sure.

 

[MvK]

I believe these are either thin or thick film hybrids, which is likely an alumina base. The traces are then co-fired precious metal and glass loaded inks. These are in simple terms a printed circuit board however which a much higher thermal characteristics than traditional PCB. Likely 800'c+ cure.

I think you are right!

 

[MvK]

War_child warning is correct, there's a good possibility those maybe BeO. Do not crush or incinerate these unless you know for sure they are not.

As far as the coating, A warm concentrated sodium hydroxide solution may work, but I don't know how that would react with BeO. I hope someone with more experience the BeO will chime in on this topic.

Nice looking material though...

I will run a small scale experiment after i have found out if its BeO or not with sodium hydroxide. Will definitely look into the BeO risks first.

Thanks for the warnings and lessons! Helps alot.

 

[orvi]

It is very hard to precisely know if something is Be containing or not. XRF does not do the thing. You can measure Al, Si and bit heavier elements tho. I don´t know if Be is used in mixtures to form ceramics, and with what element.. But I do not recommend to pulverize them. If it isn´t high frequency stuff, probably only Al2O3 ceramics. BeO is used rarely, as it is very expensive - but risk shouldn´t be underestimated.
To the "resin" problem - if it leaves white ash, and resist heat quite a bit, it´s silicone. You cannot dissolve silicone in practically any solvent. You can do it either mechanically, or by means of burning it. And both options are probably quite dangerous. You can probably put the pieces into the furnance and burn them at low temperature (ca 450-500°C), but hard to say if the ceramic won´t emmit some dust or crack upon thermal shock.

 

[macfixer01]

I agree with what Orvi said. Beryllium Oxide is more expensive and normally only used only in high output devices which get hot during operation. For example high power RF transistors, high power vacuum tubes, or the purple or white ceramic insulator material in the magnetron tubes used in microwave ovens. It has a much higher heat transfer rate than ordinary alumina ceramic although both look pretty much the same visually. I did some experimenting with a cheap diamond tester since that’s how legitimate diamonds are detected, they have a very high heat transfer rate. BeO has a much higher heat transfer rate than plain alumina ceramic, but both are still significantly less than diamond, so they both fall in the lower half of the range and seemed hard to distinguish reliably. Maybe with a better quality diamond tester and known samples of alumina and BeO for comparison, you might be able to get more reliable readings. Aside from that, those look sort of similar to the way the old Western Electric hybrid chips were made. They were a thin ceramic wafer with pins sort of clipped over the edges. All the components and gold traces were on the bottom side, and covered over with a thin layer of gray rubber. At one time I used to just scrape it off. The last ones I had I experimented with burning it off with a 4 watt blue laser. It didn’t fully burn away but ashed part of it and thinned it/loosened it enough that it was easier to rub off.

 

[MvK]

Well the burning issue stays, because when i burn the silicones the ceramic stays intact. But i get this ashy mess that you cant wash off because it is hydrophobic ash.

Whenever i add brake cleaner it will temporarily scare the silcones away, but i dont know what adding solvents to my acid will produce chemicly wise..

The above was done in a small scale test, i cant imagine what kind of mess it will make when i have to burn them all.

Im starting to hate this silicone stuff, but i wont give up on the materials just yet, challenge accepted!

Perhaps i will just send it and just burn everything to a crisp, treat the ashes with silicone solvent, rinse and burn again. But not until i have the correct safety gear to do so. Im used to 'clean' materials like contacts and cpu so ive never messed with 'plastics' before.

Thanks everyone for your input, i appreciate all of it.

 

[macfixer01]

If you just physically remove the gray silicone rubber by picking or scraping it off is there still a problem? Is there actually a second transparent coating of some kind underneath that? Maybe you’re just not heating them enough to destroy it, have you tried heating one to a dull red hot? After incineration you could also try some sodium hydroxide (Lye) solution on it to see if that affects whatever the problem residue is? For some types of resin used for potting components I know some folks use DMSO which is an industrial solvent also sold and used as a treatment for arthritis pain. You have to wear gloves because it will absorb through your skin and would carry anything dissolved in it along with the solvent.

 

[MvK]

If you just physically remove the gray silicone rubber by picking or scraping it off is there still a problem? Is there actually a second transparent coating of some kind underneath that? Maybe you’re just not heating them enough to destroy it, have you tried heating one to a dull red hot? After incineration you could also try some sodium hydroxide (Lye) solution on it to see if that affects whatever the problem residue is? For some types of resin used for potting components I know some folks use DMSO which is an industrial solvent also sold and used as a treatment for arthritis pain. You have to wear gloves because it will absorb through your skin and would carry anything dissolved in it along with the solvent.

Thank you for your answer.

The problem with scraping is the lack of space, and parts of solder sticking out so you cannot move the blade over the surface.
You can compare it to a regular green fiber board, everything is printed on the top of the ceramics. Forcing my way trough is not an option because those things are so weak they will shatter..

For the heating part, i burnt it to a crisp. It was bright red, but the coating also turns red when you heat it. I used the same torch that i used to melt my gold buttons so it should be hot enough.
I ended up with a glowing piece, and after cooling down only the top part of 1 mm was turnt into ash. After blowing off the ash you can continue this for a while until its almost bare ceramics, but then i got the problem that the the ash and the ceramics will go hydrophopic.

Maybe when i burn it all and used a solvent or lye on it after, i would be able to dip it into acid.

I paused this project for a while because my new batch of acids were delayed, right now im cleaning up some old stuff.

This weekend i will continue to battle my silicones, will keep the thread updated.

Again thx for the help!

 

[MvK]

So, today i went on with my lovely ceramic mess.

I tried to torch it for a longer time, it finally worked but only when i blasted the thing for a longer time until it exploded.

It showed some bare parts after, as seen on this pic. (part on the left still has residue on it)

I will have to find a better way to incinerate this, a bunch of hot ceramics exploding in my face is not really the way i want to go.. Maybe with a decent inceneration oven where i can manage temperature my issues are solved, but im not on this level just yet.

I think this batch will have to wait a little longer, if not i will keep u updated!

 

[MvK]

One more picture of a part just for the heck of it.

 

[orvi]

One more picture of a part just for the heck of it.

Build small hot-air "furnance". Purchase a heatgun that will allow you to regulate the temperature and goes up to minimum 600°C. Take old, preferrably stainless steel bucket or small drum. Old beer KEGs are quite durable, from quality stainless steel, and they can be found sometimes in scrapyards and re-purchased for fraction of the price. Insulate the drum/bucket with mineral wool that withstand the temperature.

Purchase stainless flexible tubing or hose, that fits to the output of the heatgun. Bore a hole into the side of the drum and shove the stainless flexible tubing inside it. Cover the top with piece of mineral wool or some other suitable heat-resistant and insulating material.

Now, you place the material into some mesh/tray with holes that way, air can flow in between the pieces of ceramic. Cover the thing and crank the heatgun on maximum temperature and power. Insides will start to heat up. Soon, you will see first signs of "smoke" - then, you take some piece of towel soaked in oil or anything suitable to light the flamable pyrolyzing gasses on fire. The material will start to burn, and as you do not use burner to heating, there is plenty of oxygen to accomplish fairly clean burning.

When the material heats up to pyrolyzing temperature, it will start to rapidly heat up - now you will lower the temperature setting on heatgun to minimum necessary to sustain high heat in the furnance. Continue till you see the burning dying down. Then, you will again set the heatgun to max temperature and accomplish full incineration of leftover carbon.

As it is silicone, air-floaty, very fine silica particles will be evolved during the process, which will fly out from the furnance outgas - be aware of this in advance and do it somewhere far away from homes and people and WEAR QUALITY PARTICULATE RESPIRATOR.

Incinerated material should be then left to cool down and soaked in water to minimize dusting from remaining extremely fine silica powder created from silicone. You can help to wet it using JetDry, or any other surfactant like dish soap.

Be careful and aware of silicosis - because this is the stuff (floaty silica dust from burned silicone) that is the worst in terms of health hazard associated with this disease. Beryllium presence possibility is only the "cherry on top". But as long as you keep the temperature relatively low, risk of emitting some Be compounds to the air should be low. But not zero Stay safe.

 

[eaglekeeper]

So, today i went on with my lovely ceramic mess.

I tried to torch it for a longer time, it finally worked but only when i blasted the thing for a longer time until it exploded.

It showed some bare parts after, as seen on this pic. (part on the left still has residue on it)

I will have to find a better way to incinerate this, a bunch of hot ceramics exploding in my face is not really the way i want to go.. Maybe with a decent inceneration oven where i can manage temperature my issues are solved, but im not on this level just yet.

I think this batch will have to wait a little longer, if not i will keep u updated!

I could be wrong... but I would save all the gray stuff that chips off. There is a possibility that there are some gold bonding wires caught up in it.

 

[MvK]

I could be wrong... but I would save all the gray stuff that chips off. There is a possibility that there are some gold bonding wires caught up in it.

I try to process everything as much as i can, thanks!

 

[MvK]

Build small hot-air "furnance". Purchase a heatgun that will allow you to regulate the temperature and goes up to minimum 600°C. Take old, preferrably stainless steel bucket or small drum. Old beer KEGs are quite durable, from quality stainless steel, and they can be found sometimes in scrapyards and re-purchased for fraction of the price. Insulate the drum/bucket with mineral wool that withstand the temperature.

Purchase stainless flexible tubing or hose, that fits to the output of the heatgun. Bore a hole into the side of the drum and shove the stainless flexible tubing inside it. Cover the top with piece of mineral wool or some other suitable heat-resistant and insulating material.

Now, you place the material into some mesh/tray with holes that way, air can flow in between the pieces of ceramic. Cover the thing and crank the heatgun on maximum temperature and power. Insides will start to heat up. Soon, you will see first signs of "smoke" - then, you take some piece of towel soaked in oil or anything suitable to light the flamable pyrolyzing gasses on fire. The material will start to burn, and as you do not use burner to heating, there is plenty of oxygen to accomplish fairly clean burning.

When the material heats up to pyrolyzing temperature, it will start to rapidly heat up - now you will lower the temperature setting on heatgun to minimum necessary to sustain high heat in the furnance. Continue till you see the burning dying down. Then, you will again set the heatgun to max temperature and accomplish full incineration of leftover carbon.

As it is silicone, air-floaty, very fine silica particles will be evolved during the process, which will fly out from the furnance outgas - be aware of this in advance and do it somewhere far away from homes and people and WEAR QUALITY PARTICULATE RESPIRATOR.

Incinerated material should be then left to cool down and soaked in water to minimize dusting from remaining extremely fine silica powder created from silicone. You can help to wet it using JetDry, or any other surfactant like dish soap.

Be careful and aware of silicosis - because this is the stuff (floaty silica dust from burned silicone) that is the worst in terms of health hazard associated with this disease. Beryllium presence possibility is only the "cherry on top". But as long as you keep the temperature relatively low, risk of emitting some Be compounds to the air should be low. But not zero Stay safe.

I have purchaced some quality respirators so no silica or beryllium will enter me anytime soon! Because i process alot of different types of material in the future i will either build or buy an oven like you described.

I started in the garden with a stupid youtube video where everything went wrong, right now my garage is starting to look like a proper lab with glassware and a fumehood. Will expand with an oven soon.

Most of the problems im having is just lack of proper gear, but im making my way up there slowly.

Thanks for your input!

 

[Yggdrasil]

I have purchaced some quality respirators so no silica or beryllium will enter me anytime soon! Because i process alot of different types of material in the future i will either build or buy an oven like you described.

I started in the garden with a stupid youtube video where everything went wrong, right now my garage is starting to look like a proper lab with glassware and a fumehood. Will expand with an oven soon.

Most of the problems im having is just lack of proper gear, but im making my way up there slowly.

Thanks for your input!

Just make sure you have no open canisters of acid in the garage.
HCl and Nitric will eat any exposed metal in no time.
Nails and screws that hold it together also.

 

[orvi]

Just make sure you have no open canisters of acid in the garage.
HCl and Nitric will eat any exposed metal in no time.
Nails and screws that hold it together also.

Yeah. It is good to know, that chlorides espetially are catalyst for corrosion of ferrous alloys. So if it rust once from deposition of HCL onto ferrous surfaces, it will go with air humidity practically indefinitely, regardless of the fact you stop contamining with more HCL. Unless you wipe surface clean, corrosion does not stop

So, in the design of fume hood, try to make effort to use metal parts only where it is strictly necessary.