Average PM and metal content in RRU's

[andu]

So i'm wondering if anyone has any idea of metal content in Remote Radio Units? They are 4G 15k and 25kg models I got three pieces for now but I don't wanna overpay. I can share some pics if needed.

The kind of alu used would also be a plus, these are all huawei btw.
I opened them up a bit but they fairly complex and populated things, like silver coated copper and heavily flashed/plated boards, one of the two big boards is a thin pcb stuck into a aluminium plate, with some components being directly cooled by that plate (which btw upon googling they can get quite pricy and there are two on each plate-boards)

 

[Darkthirty]

So i'm wondering if anyone has any idea of metal content in Remote Radio Units? They are 4G 15k and 25kg models I got three pieces for now but I don't wanna overpay. I can share some pics if needed.

The kind of alu used would also be a plus, these are all huawei btw.
I opened them up a bit but they fairly complex and populated things, like silver coated copper and heavily flashed/plated boards, one of the two big boards is a thin pcb stuck into a aluminium plate, with some components being directly cooled by that plate (which btw upon googling they can get quite pricy and there are two on each plate-boards)

Scrapyard XRF will give you the aluminum alloy

 

[andu]

Scrapyard XRF will give you the aluminum alloy

I will have to go and ask, two times i ended up getting rid of a couple bunches i got paid less than for the lead, but it is as strong as steel. Id rather have my own xrf , will try this option once i gathered up some scrap i won't process.

 

[spectrumpainters]

mate be careful with this stuff.

(edit: to add after reading and not wanting to scare you but at same time you need a VERY healthy fear of this)


the components you are talking about that are fixed to cooling plates are LDMOS transisters. the white thing on the top is probably not, (depending on the date of manufacture), but also possibly, (and even manufacture date wont guarantee), Beryllium oxide. One of the most toxic substances known to man. do your research for many many months before you muck around. There's other stuff too to be aware of that is dangerous.
Dependind on the year, the alloy is likely AlSi9cu3 of some sort, die cast alu but silver plated and ammount of platimg again is by year. Plating gets more efficient in PM use, the rf cavity only requires enough silver plating that the signal sort of floats over the surface instead of conducting inside like electrical.
i would dispose of all of the plastic, make it all stackable and wait until you know what you are doing because by then you'll get more money for your stuff because you will know what it. gear looks pretty newish so prob Al oxide so prob ok but the other option is not vaguely ok risk management.

.0002ug is the daily occupational exposure limit for Beryllium. public exposure is 1/10th of that. it will accumulate in your clothes and you'll expose family/friends/neighbours etc

idea has gotta be be :

wait, learn everything, stack and when you know the score you get 10X more $ cause you know what you have

if you don't want to learn, bail now because new gear is slim pickings and you have to know your buyer so can sell some component/be creative with re-use


berylium copper is another thing in there, so no refining, probably ever, risk/reward is not even close to worth it

gl, find a buyer who specializes, this isn't mobile phones that are made with all the enviro/disposal considerations. aim was make it - fast/go hard/no matter the cost amd make $ and enviro laws exclude this sort of stuff on social/economics needs

take care

 

[andu]

These are 4/4.25g so i'd like to think beryllium shouldn't be present, there's not much plastic but i do get rid of it, I did open a couple of them but till i can melt the aluminum they take less space as they are. The white thing is grey and is thermal paste, the box itself is like a cooler.
You did make me be more careful with these, it taking a long while to learn what's in my hands. I think manufacturing year is written on somewhere.
The lasers seem pretty well stocked on gold if i were to raise them separately.

If i knew exactly what i have in my hands and tools/space to process it would be great as I could get plenty of these.

 

[kurtak]

the components you are talking about that are fixed to cooling plates are LDMOS transisters. the white thing on the top is probably not, (depending on the date of manufacture), but also possibly, (and even manufacture date wont guarantee), Beryllium oxide.

Per the bold print - you are talking about beryllium oxide that is in fact a ceramic

As a ceramic it will not dissolve in acids (nitric, HCl or AR) so is of NO concern !!!

Also - being ceramic - it ONLY becomes a concern if it is ground to a FINE powder that can become airborne & breathed in - other wise it is of no health risk !!!

berylium copper

That is a different story as the beryllium is actually alloyed with the copper & will go into solution along with the copper when dissolving the copper thereby creating a VERY toxic solution

I don't see ANY reason for beryllium copper being used in the components shown in this thread

Beryllium copper in electronic scrap is only used where the copper needs to act as a spring

Kurt

 

[kurtak]

If these are silver plated aluminum you can strip the silver plating with dilute nitric

Nitric does not react with aluminum (especially if diluted) so the nitric will dissolve the silver & leave the aluminum untouched

Kurt

 

[Martijn]

Beryllium copper in electronic scrap is only used where the copper needs to act as a spring

Kurt

In electronic scrap yes, but beware with copper tools from work, spark-free copper and bronze tools tend to have beryllium in them.
so spark free or springy copper things = do not dissolve!
https://www.weidinger.eu/en/tools/non-sparking-tools

 

[Martijn]

I don't see the use for a spark free welding hammer though... but it's also available

 

[Yggdrasil]

I don't see the use for a spark free welding hammer though... but it's also available

You know there are good sparks and bad sparks

 

[spectrumpainters]

Per the bold print - you are talking about beryllium oxide that is in fact a ceramic

As a ceramic it will not dissolve in acids (nitric, HCl or AR) so is of NO concern !!!

Also - being ceramic - it ONLY becomes a concern if it is ground to a FINE powder that can become airborne & breathed in - other wise it is of no health risk !!!


That is a different story as the beryllium is actually alloyed with the copper & will go into solution along with the copper when dissolving the copper thereby creating a VERY toxic solution

I don't see ANY reason for beryllium copper being used in the components shown in this thread

Beryllium copper in electronic scrap is only used where the copper needs to act as a spring

Kurt

 

[spectrumpainters]

guys, i understand the comments on specific points but i'm talking about a substance with a .0001ug daly public exposure limit with concerns for the safety of someone new to this who it turbs out was unaware so would it be a big thing if we avoided dismissing the concerns?

i didn't convey clearly re: the LDMOS so my bad but it is an issue and i'll explain that, it was a rushed response with the aim of alertimg OP so a wasnt going out of my way to be specific, when the risk is death, details aren't front and centre. also there are assumptions made about beryllium the are out right false so i would say safety first would be a good idea.

i'm happy firstly, because it's 4g gear, looks corect. there are issues with age of gear used to plan for safety that i might get into but if you read ROHS rules made in early 2000s + clauses/industrial use exclusions and the response/green washing by manufactures it becomes way too muddy and expecting the worse is a reasonable approach.

so the mosfets, sure it's a ceramic, i had in mind some models which had aswell, a paste of beo for heat sync between the mounting bar and the die. that is not a ceramic and that IS enough to kill you many many times over. but that is pretty specific and i will not say when every manufacture stopped doing that because imo it's reckless but should not be a thing in this case.

the main concern is this.


beryllium does NOT only add spring or non spark features to copper. that's the assumption that needs to be checked because it's used atleast to reduce thermal elongation.

pretty big deal when these mos are designed for use at ULTRA high frequency and it's design concept relies opun the gates being of a predetermined physical size.

but it goes way beyong that. in RF, physical shape changes effect signal and as such, designs for all manner or components will use metaps/alloys with extremely low elongation realtive to whatever else you think all this stuff is made of.

other basic general knowledge points would be that

- ceramics can shatter/be scratched/worn.

alloys can wear, especially those like beryllium copper which sacrifice maleablity, aka they are brittle! try to snap a piece of 2mm2 copper wire and record how many bends on one point it takes.

then find the same guage in becu and it will take 1 bend

but there's none in electronics so i guess wait till someone leaves some old golf clubs on the curb right?

 

[spectrumpainters]

These are 4/4.25g so i'd like to think beryllium shouldn't be present, there's not much plastic but i do get rid of it, I did open a couple of them but till i can melt the aluminum they take less space as they are. The white thing is grey and is thermal paste, the box itself is like a cooler.
You did make me be more careful with these, it taking a long while to learn what's in my hands. I think manufacturing year is written on somewhere.
The lasers seem pretty well stocked on gold if i were to raise them separately.

If i knew exactly what i have in my hands and tools/space to process it would be great as I could get plenty of these.

i think you and glad you understand my concerns. the paste you talkung about is likely nor beo at all but stay safe and dyor.all the best

 

[spectrumpainters]

i think you and glad you understand my concerns. the paste you talkung about is likely nor beo at all but stay safe and dyor.all the best

* i think you are ok, (walking dogs and typing ha)

 

[spectrumpainters]

guys, i understand the comments on specific points but i'm talking about a substance with a .0001ug daly public exposure limit with concerns for the safety of someone new to this who it turbs out was unaware so would it be a big thing if we avoided dismissing the concerns?

i didn't convey clearly re: the LDMOS so my bad but it is an issue and i'll explain that, it was a rushed response with the aim of alertimg OP so a wasnt going out of my way to be specific, when the risk is death, details aren't front and centre. also there are assumptions made about beryllium the are out right false so i would say safety first would be a good idea.

i'm happy firstly, because it's 4g gear, looks corect. there are issues with age of gear used to plan for safety that i might get into but if you read ROHS rules made in early 2000s + clauses/industrial use exclusions and the response/green washing by manufactures it becomes way too muddy and expecting the worse is a reasonable approach.

so the mosfets, sure it's a ceramic, i had in mind some models which had aswell, a paste of beo for heat sync between the mounting bar and the die. that is not a ceramic and that IS enough to kill you many many times over. but that is pretty specific and i will not say when every manufacture stopped doing that because imo it's reckless but should not be a thing in this case.

the main concern is this.


beryllium does NOT only add spring or non spark features to copper. that's the assumption that needs to be checked because it's used atleast to reduce thermal elongation.

pretty big deal when these mos are designed for use at ULTRA high frequency and it's design concept relies opun the gates being of a predetermined physical size.

but it goes way beyong that. in RF, physical shape changes effect signal and as such, designs for all manner or components will use metaps/alloys with extremely low elongation realtive to whatever else you think all this stuff is made of.

other basic general knowledge points would be that

- ceramics can shatter/be scratched/worn.

alloys can wear, especially those like beryllium copper which sacrifice maleablity, aka they are brittle! try to snap a piece of 2mm2 copper wire and record how many bends on one point it takes.

then find the same guage in becu and it will take 1 bend

but there's none in electronics so i guess wait till someone leaves some old golf clubs on the curb right?

and yes i know the alloy diff to oxide but i'm not about to dust my work bench and clothes with it

 

[Yggdrasil]

and yes i know the alloy diff to oxide but i'm not about to dust my work bench and clothes with it

Please use proper English, since many of our members use translators real English are needed.
Next, there are no such thing as beo in chemistry. It is BeO.

And that is in fact the ceramic component.
As other cerams it is basically an Oxide of their metals.
ZrO, MgO and AlO are some others.

 

[spectrumpainters]

from the largest ptoducer in the usa



"To remove heat, most Si power transistors are soldered to their substrate with gold/silicon solder. Since AuSi is a “hard” solder, the thermal expansion of the substrate should be between 3 and 10 x 10-6 /°C, in order to prevent cracking of the Si upon temperature cycling. The substrate can either be a dielectric or electrical conductor, depending on the type of transistor. Si VMOS and bipolar transistors must be soldered onto an electrically isolated pad on a thermally conductive dielectric. Materion’s BeO ceramic substrates, known as Thermalox™ BeO, offer a unique combination of high thermal conductivity, high electrical resistivity and low dielectric loss over a wide frequency range. Materion provides hot pressed BeO ceramic substrates, manufactured at its Tucson, AZ facility, to meet this requirement. Materion’s facility in Newburyport, MA then screen prints patterns of thick film MoMn paste that is fired onto the BeO, plated with Ni and then brazed into a package using braze alloys supplied by Materion’s facility in Buffalo, NY.

In the mid-1990’s Motorola invented a new type of RF transistor called LDMOS. LDMOS transistors could be soldered directly to an electrically grounded metal flange, thereby eliminating the need for BeO. The elimination of BeO reduced the cost of the package, as well as reduced the overall thermal resistance since most BeO packages contain a flange brazed beneath the BeO. LDMOS transistors ramped up in popularity by the end of the 1990’s. With the conversion from analog to digital cell phones in the early 2000’s LDMOS transistors dominated the market for amplifiers for cellular base stations.

Going forward, Materion is addressing other requirements of the RF transistor industry by manufacturing air cavity packages comprised of a ceramic frame brazed to a metal flange. The industry is demanding flanges with higher thermal conductivity and lower cost. Materion offers brazed ceramic packages with flanges made of CuW, CMC and CPC (Table 1). Various Materion locations are working with key customers to develop flanges made of copper, which will require an entirely new method to solder Si onto the flange due to the severe thermal expansion mismatch between Si and Cu."

but sure, nothing to see here.

except me not capitalizing a chem formula when i'm walking the dog

atleast now i know daily public exposure limit is for not using caps

me on the other hand, i can take 10X the exposure apparently, that helps because i've seen the non-hardened ceramic version of the stuff i was trying to warn OP about before i realized this is one of THOSE forum cultures where cred is more important than imfo

 

[Yggdrasil]

from the largest ptoducer in the usa



"To remove heat, most Si power transistors are soldered to their substrate with gold/silicon solder. Since AuSi is a “hard” solder, the thermal expansion of the substrate should be between 3 and 10 x 10-6 /°C, in order to prevent cracking of the Si upon temperature cycling. The substrate can either be a dielectric or electrical conductor, depending on the type of transistor. Si VMOS and bipolar transistors must be soldered onto an electrically isolated pad on a thermally conductive dielectric. Materion’s BeO ceramic substrates, known as Thermalox™ BeO, offer a unique combination of high thermal conductivity, high electrical resistivity and low dielectric loss over a wide frequency range. Materion provides hot pressed BeO ceramic substrates, manufactured at its Tucson, AZ facility, to meet this requirement. Materion’s facility in Newburyport, MA then screen prints patterns of thick film MoMn paste that is fired onto the BeO, plated with Ni and then brazed into a package using braze alloys supplied by Materion’s facility in Buffalo, NY.

In the mid-1990’s Motorola invented a new type of RF transistor called LDMOS. LDMOS transistors could be soldered directly to an electrically grounded metal flange, thereby eliminating the need for BeO. The elimination of BeO reduced the cost of the package, as well as reduced the overall thermal resistance since most BeO packages contain a flange brazed beneath the BeO. LDMOS transistors ramped up in popularity by the end of the 1990’s. With the conversion from analog to digital cell phones in the early 2000’s LDMOS transistors dominated the market for amplifiers for cellular base stations.

Going forward, Materion is addressing other requirements of the RF transistor industry by manufacturing air cavity packages comprised of a ceramic frame brazed to a metal flange. The industry is demanding flanges with higher thermal conductivity and lower cost. Materion offers brazed ceramic packages with flanges made of CuW, CMC and CPC (Table 1). Various Materion locations are working with key customers to develop flanges made of copper, which will require an entirely new method to solder Si onto the flange due to the severe thermal expansion mismatch between Si and Cu."

but sure, nothing to see here.

except me not capitalizing a chem formula when i'm walking the dog

atleast now i know daily public exposure limit is for not using caps

me on the other hand, i can take 10X the exposure apparently, that helps because i've seen the non-hardened ceramic version of the stuff i was trying to warn OP about before i realized this is one of THOSE forum cultures where cred is more important than imfo

Information is crucial in most respects, and in chemistry it actually has significance if it is in caps or not, so that is also a part of the information.
We do not care less of spelling in other respects other than with proper language for the non English speakers using translators.
Credits do not matter, proper information does!

Edit to add:
Thanks for the information by the way, there was much of interest here.

 

[spectrumpainters]

Information is crucial in most respects, and in chemistry it actually has significance if it is in caps or not, so that is also a part of the information.
We do not care less of spelling in other respects other than with proper language for the non English speakers using translators.
Credits do not matter, proper information does!

Edit to add:
Thanks for the information by the way, there was much of interest here.

i understand and that is not a problem.

i'll make the point without reactivity, (which can happen when health concerns are involved.)

so:

yes it's a ceramic. and the cap + substrate on die is a hardened form.

it is also a ceramic when added to a paste or something similar. pastes dry out, especially in one of our fields of interest, old electronics

 

[spectrumpainters]

BeO, a ceramic can be added in powdered form to other materials like heat paste etc

this is another thing that's endlessley important, (i haven't been around here long so i don't know how much it's been covered, but it bears repeating because I like most of the the ppl i've seen on yt doing this and would lile them to be around for longer than 1 bad exposure haha)

- when manufacturers have an exclusion for the use of a substance for reasons like national security/critical infrastructure/machinery/medical purposes, they aren't incentivised to give a shit about the consequences to human health - so given the track record of pretty much every large corporation ever:

Expect that they will continue to use BeO, (and anything else they spruk about ceasing to use in consumer goods), until they can find a cheaper method/material, or until the benefit is outweighed by the legal consequences of class actions.

there's endless examples

it even goes further like in the caee of asbestos being known by manufacturers to be a carcinogen, who continued it's use in even consumer goods

like cohen said "but everybody knows"

so lets be safe

if it's nasty, expecting it to be found in Industrial gear until you have DOYR, so you can eliminate the possibilty is beyond a wise approach

especially with quantities we want to source and the quantities that could nuke a whole suburb, or being caught on your clothes in the same washing machine as....

(Beryllium building up overtime in filters etc is why Be alloy foundaries - of which there are as few as few as 3 total in the whole of the USA because it's so dangerous, have safety measures for physical seperation between workplace and home),

...as the washing machine used used for your kids clothes