Coke cans?
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Coke cans?
This is meant as a serious "tech" question from an ancient engineer, but if a mod sees it needs moving, so be it.
Over the years, watching tired and ancient airframes being reduced to shreds (and yes, sometimes with a lump in one's throat):
What happens to the scrap?
- A lot of it is some variety of aluminium alloy, but it must be full of other "stuff", like fasteners, fuel lines, hydraulic lines, wiring, seals, plastic, etc.
- But, things like Coke cans and tooth paste tubes are extruded from nearly pure aluminium.
- AU2GN (RR58) as used on Concorde, and I suspect most modern aircraft construction alloys as well, are anything but pure aluminium.
So my question is...
Is a certain amount of alloy recoverable for re-use as base material for manufacturing aviation-grade alloy ingots, or is it all just melted down and separated, and only the aluminium as such is used (with maybe some of the other constituents skimmed off and re-used) ?
CJ
Over the years, watching tired and ancient airframes being reduced to shreds (and yes, sometimes with a lump in one's throat):
What happens to the scrap?
- A lot of it is some variety of aluminium alloy, but it must be full of other "stuff", like fasteners, fuel lines, hydraulic lines, wiring, seals, plastic, etc.
- But, things like Coke cans and tooth paste tubes are extruded from nearly pure aluminium.
- AU2GN (RR58) as used on Concorde, and I suspect most modern aircraft construction alloys as well, are anything but pure aluminium.
So my question is...
Is a certain amount of alloy recoverable for re-use as base material for manufacturing aviation-grade alloy ingots, or is it all just melted down and separated, and only the aluminium as such is used (with maybe some of the other constituents skimmed off and re-used) ?
CJ
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Anything of value is melted down and sold on by the company who 'trash' the aircraft. Key fluids are recycled. I believe airlines have a recycling method as well for maintenance aka anything which is expensive to buy, but can be reused will be given back to them for use in the future.
The alloys etc are sold onto whoever needs it. There are many rare metals in modern aircraft that are put to use in the making and maintenance of craft.
This is my limited knowledge.
The alloys etc are sold onto whoever needs it. There are many rare metals in modern aircraft that are put to use in the making and maintenance of craft.
This is my limited knowledge.
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Not being an engineer, I read a few articles (not written by engineers) that said that reclycled aluminium goes into articles of less quality, i.e. it goes from aircraft, then scrapped, then to cans, or consumer products or wires aso.
If my memory is correct, I lately read that you can use now reclycled aluminium also for aircraft again. I guess because of sophisticated melting technology, allowing higher metal purity. Maybe they mix new and old alu together.
Dani
If my memory is correct, I lately read that you can use now reclycled aluminium also for aircraft again. I guess because of sophisticated melting technology, allowing higher metal purity. Maybe they mix new and old alu together.
Dani
Just how much and how quickly the aluminium gets back in the sky depends on a few things.
Fairly large parts from aircraft which have very distinct alloy usages in distinct parts of the airframe are easily sorted at the break down stage so these can be meletd & recycled into a new batch of their given alloy as soon as there is a melt of that grade.
What helps is this instance as well is that most parts are designed to have a serial number always visible on them, which makes tracing the alloy grade dead easy. What doesn't help is when the tear down splits parts into two or more pieces.
When the parts aren't easily identified as any given alloy, then it's into the general melt. If the foundry is a specialist producer of aviation grade alloys, then they'll melt a batch of material to see which grade the resulting mix is closest to and then add either more scrap where the grade is known, or they'll add relatively pure ingredients into the melt to bring the overall balance of chemical elements into the ranges for each one within the alloy grade, or to bring the alloy mix into the range for a specific grade if they have an oder for that grade.
If they don't have a specific need then they'll often melt the scrap into batches and take an analysis of each one before casting it into ingots. In that way they can put material into stock, knowing then just what they need to add into the mix to take each "stock-melt" into a given alloy.
This doesn't just happen with aluminium, or aluminum to our US colleagues, but with the vast majority of metals currently in service. Sometimes of course, it actually takes an addition of a compound maybe limestone and maybe oxygen blown through to remove undesirable elements from a melted alloy to meet the specified limits.
Metal recycling is nothing new - I recall from my college days our metallurgy lecturer telling us that most modern steel has been recycled between 5 and 10 times and that aluminium was fast catching up, despite the increasing exploitation of reserves and increasing volume of these materials being produced annually.
Hope this helps.
Fairly large parts from aircraft which have very distinct alloy usages in distinct parts of the airframe are easily sorted at the break down stage so these can be meletd & recycled into a new batch of their given alloy as soon as there is a melt of that grade.
What helps is this instance as well is that most parts are designed to have a serial number always visible on them, which makes tracing the alloy grade dead easy. What doesn't help is when the tear down splits parts into two or more pieces.
When the parts aren't easily identified as any given alloy, then it's into the general melt. If the foundry is a specialist producer of aviation grade alloys, then they'll melt a batch of material to see which grade the resulting mix is closest to and then add either more scrap where the grade is known, or they'll add relatively pure ingredients into the melt to bring the overall balance of chemical elements into the ranges for each one within the alloy grade, or to bring the alloy mix into the range for a specific grade if they have an oder for that grade.
If they don't have a specific need then they'll often melt the scrap into batches and take an analysis of each one before casting it into ingots. In that way they can put material into stock, knowing then just what they need to add into the mix to take each "stock-melt" into a given alloy.
This doesn't just happen with aluminium, or aluminum to our US colleagues, but with the vast majority of metals currently in service. Sometimes of course, it actually takes an addition of a compound maybe limestone and maybe oxygen blown through to remove undesirable elements from a melted alloy to meet the specified limits.
Metal recycling is nothing new - I recall from my college days our metallurgy lecturer telling us that most modern steel has been recycled between 5 and 10 times and that aluminium was fast catching up, despite the increasing exploitation of reserves and increasing volume of these materials being produced annually.
Hope this helps.
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Originally Posted by Donkey497
Just how much and how quickly the aluminium gets back in the sky depends on a few things.....
The rest of your post answered exactly all I was asking!
Apart from anything else, that is a nice thing about PPRUNe. Ask a question, and you promptly get an answer!
As to the Coke and Tesco and Tennant cans.... and alu toothpaste tubes (do they still exist?) they're extruded from near-pure alu pellets. Too much other metals in there ruin the extrusion process (my Dad worked in that business, which, I admit, partially triggered my question
).So, among other things, from what Donkey497 explained...
Not that much of F-BVFD (the one Concorde that was scrapped) ended up as Stella beer cans. Some of it even may still be flying around somewhere. Pleasing thought somehow.
CJ
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Originally Posted by colsie
May i then ask what occurs with the composite aircraft when and if they are retired?
You certainly can't turn them into beercans, or even into base material for new aircraft.
They may turn out to be the same kind of albatrosses as the "hybrid" cars, seemingly a good idea, but overall more of a problem to manufacture, and far more of a problem to dispose of.
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Have heard but can't confirm the recycled alloy from aircraft is hight prized as the metal to make alloy engine blocks ....
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colsie:
May i then ask what occurs with the composite aircraft when and if they are retired?
May i then ask what occurs with the composite aircraft when and if they are retired?
This is nothing new, since already todays aircraft have considerable percentages of non-reusable materials. Think about the seat tissue, the cabine covers, but also heavy structurs like the vertical stabilizer of an A300 (of which the first ones are slowly being retired) are non-reusable (stabilizer: composite material).
You also have to forget the notion that composite aircraft are made of fibers/resin only. Modern heavy duty composites like on the 787 partly consist of light weight metals. They first have to be extracted from the composite and can then be recycled.
Dani
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This is meant as a serious "tech" question from an ancient engineer
(a) I have an affinity with that class of folk who might be described as ancient engineers .. (olde pharts between ourselves ....)
(b) it doesn't have to be terribly related to flying to be OK for tech log .. main thing is it needs to be of interest to (at least some of) the assembled folk ...
(c) my favourite not terribly related to flying thread had to do with Chinese cryptography ... I guess that we could figure out some relevance to flying over an ale ... perhaps ... and I figure that's enough justification to leave it run ....
... I thought that the thread was fascinating .... it really is amazing what one can learn from the incredibly catholic wealth of knowledge represented by the assembled PPRuNe fraternity ...
(d) coke cans ? .. some pilots drink Coke ... close enough for me ...
(a) I have an affinity with that class of folk who might be described as ancient engineers .. (olde pharts between ourselves ....)
(b) it doesn't have to be terribly related to flying to be OK for tech log .. main thing is it needs to be of interest to (at least some of) the assembled folk ...
(c) my favourite not terribly related to flying thread had to do with Chinese cryptography ... I guess that we could figure out some relevance to flying over an ale ... perhaps ... and I figure that's enough justification to leave it run ....
... I thought that the thread was fascinating .... it really is amazing what one can learn from the incredibly catholic wealth of knowledge represented by the assembled PPRuNe fraternity ...
(d) coke cans ? .. some pilots drink Coke ... close enough for me ...
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Thanks, John !
This olde phart hails from the days when glueing, and chemical and numerically controlled milling for large structural parts, were still relatively new techniques....
Quite likely, although I would have thought the first source would be... old engine blocks ! Easier to strip of extraneous bits and pieces, and already pretty much the right composition.
Are those a part of the composite itself (as in fibers, strands, mats, etc.) ? Or are they structural items embedded in or attached to the composite (such as, e.g., hinges) ?
This olde phart hails from the days when glueing, and chemical and numerically controlled milling for large structural parts, were still relatively new techniques....
Originally Posted by Bolty McBolt
Have heard that recycled alloy from aircraft is highly prized as the metal to make alloy engine blocks ...
Originally Posted by Dani
Modern heavy duty composites like on the 787 partly consist of light weight metals. They first have to be extracted from the composite and can then be recycled.
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as I said, I'm no specialist. The only thing I know is from aviation magazines and the aircraft I made conversion training on.
As I remember, composite structures are made in layers. Depending on the technology, the use and the strenght, they include metals like Aluminium, Magnesium and Titanium. Or any blend of it.
I also remember in an old Mirage III where the honeycomb structure was made of metals, i.e. the comb itself was made of very thin metal sheets.
On the 787 you have additional technologies: Bolts, hinges and any sort of conections are put into the resin structures. On the A350 they want to have similar sandwich structures, but with more metals in it. I can imagine that they will just include more layers of metal instead of kevlar/fibreglass/other fibres. They are mainly talking about Magnesium, but so far design is not yet freezed.
If you want to know more, try Wikipedia, e.g. under "Glare" ("GLAss-REinforced" Fibre Metal Laminate).
As I remember, composite structures are made in layers. Depending on the technology, the use and the strenght, they include metals like Aluminium, Magnesium and Titanium. Or any blend of it.
I also remember in an old Mirage III where the honeycomb structure was made of metals, i.e. the comb itself was made of very thin metal sheets.
On the 787 you have additional technologies: Bolts, hinges and any sort of conections are put into the resin structures. On the A350 they want to have similar sandwich structures, but with more metals in it. I can imagine that they will just include more layers of metal instead of kevlar/fibreglass/other fibres. They are mainly talking about Magnesium, but so far design is not yet freezed.
If you want to know more, try Wikipedia, e.g. under "Glare" ("GLAss-REinforced" Fibre Metal Laminate).
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Thanks, Dani !
Metal-metal honeycomb is not really a "composite", and it's well over 40 years old.
The Mirage III you mentioned is an example, so are aircraft floors on too many aircraft to list, so are the Concorde elevons and rudders, and the nozzle/reverser buckets.
Metal-metal honeycomb is not really a "composite", and it's well over 40 years old.
The Mirage III you mentioned is an example, so are aircraft floors on too many aircraft to list, so are the Concorde elevons and rudders, and the nozzle/reverser buckets.
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Perhaps someone could answer this little tag question. Why is it that many ships (my dad's old ship HMCS McKennzie as example) and even old NY subway trains are sunk as artificial reefs instead of being melted down? I know they are mostly iron, not much more expensive Al, but still would think they would be cut up and melted before being sunk.
As to why your dad's old ship & new york sub way cars are being sunk rather than recycled. there's a few considerations, some green, some not so.
Considering your old man's ship first. If it had been a comercial cargo carrier the odds are that it would have been run up a beach in India or Pakistan years ago & would have been scrapped, cut up and recycled that way. As it was a warship "of a certain age" its a bit more murky. The odds are that in its construction specialist (military) steel grades (specifically armour plate) were used in specific parts of its construction. Even although that happened 50 years ago there are still probably some alloying secrets which would be revealed by normal scrapping & that may still be prevented by either government edict or by a commercial contract.
FYI - Modern warships are pretty woossy in comparison to historical warships. WWII design vintage frigates, cruisers & battleships used high strength steel plates up to and heavier than 12" or 300mm thick. Modern ships do use high strength steels, but they are not generally armour plate and are nowhere near as thick. If you get a chance, compare the view along the waterline of say the USS Iowa (WWII Battleship) with say HMS Illustrious (1970's designed Through-Deck Cruiser/ very Light Carrier). On a sunny day, the battleship has a nice smooth waterline look, but on the newer boat, you can see every frame and rib stand out as a high point along the waterline in the reflected light. All this is because the plates used in modern ships are so much thinner (& hence more flexible) than was used even recently.
Secondly, even altough the ship was decommissioned over 10 years ago, the actual layout of the ship may reveal operational specifications of current naval equipment which may be undesirable to give away, on the open market, if the ship were offered for commercial scrapping.
Thirdly, by the time sensitive equipment, ancillary parts and cabling is removed, it may actually be uneconomical to a commercial scrapper to take the ship on as the material that remains may not be economically viable to cut up & recycle.
Similarly with the new york sub way cars, once the motors, cabling & mandatory or easily recycled stuff comes off it might not be economic to recycle the rest.
However, using these redundant vehicles for the creation of artificial reefs has distinct attractions:-
Where there are reefs, fish are able to breed and multiply hence improving commercial and recreational fisheries.
Where there are shallow accessible reefs in diving areas, dive tourism increases.
Where the artificial reefs are composed of semi-familiar objects used in unfamiliar arrangements such as the sub way cars, this has a secondary boost to the dive tourism. There are people sad enough to don rubber head to toe, strap air tanks to their back and spend hours in cold seawater, just to get one of their freinds to take a photgraph of them sitting ina subway car looking as if they are reading a paper. If this opinion offends some, tough, it's actually a quote from my cousin who used to run a dive shool in the Caymans.
Establishing an artificial reef also has benefits in land reclamation as it establishes an offshore hard edge to mitigate erosion of material between the reef and the existing shore.
Finally, an offshore reef has a dramatic effect in reducing the effects of offshore storms on beach front areas, which especially along parts of the US atlantic coast and Gulf of Mexico is a serious concern.
Hope this helps.
Considering your old man's ship first. If it had been a comercial cargo carrier the odds are that it would have been run up a beach in India or Pakistan years ago & would have been scrapped, cut up and recycled that way. As it was a warship "of a certain age" its a bit more murky. The odds are that in its construction specialist (military) steel grades (specifically armour plate) were used in specific parts of its construction. Even although that happened 50 years ago there are still probably some alloying secrets which would be revealed by normal scrapping & that may still be prevented by either government edict or by a commercial contract.
FYI - Modern warships are pretty woossy in comparison to historical warships. WWII design vintage frigates, cruisers & battleships used high strength steel plates up to and heavier than 12" or 300mm thick. Modern ships do use high strength steels, but they are not generally armour plate and are nowhere near as thick. If you get a chance, compare the view along the waterline of say the USS Iowa (WWII Battleship) with say HMS Illustrious (1970's designed Through-Deck Cruiser/ very Light Carrier). On a sunny day, the battleship has a nice smooth waterline look, but on the newer boat, you can see every frame and rib stand out as a high point along the waterline in the reflected light. All this is because the plates used in modern ships are so much thinner (& hence more flexible) than was used even recently.
Secondly, even altough the ship was decommissioned over 10 years ago, the actual layout of the ship may reveal operational specifications of current naval equipment which may be undesirable to give away, on the open market, if the ship were offered for commercial scrapping.
Thirdly, by the time sensitive equipment, ancillary parts and cabling is removed, it may actually be uneconomical to a commercial scrapper to take the ship on as the material that remains may not be economically viable to cut up & recycle.
Similarly with the new york sub way cars, once the motors, cabling & mandatory or easily recycled stuff comes off it might not be economic to recycle the rest.
However, using these redundant vehicles for the creation of artificial reefs has distinct attractions:-
Where there are reefs, fish are able to breed and multiply hence improving commercial and recreational fisheries.
Where there are shallow accessible reefs in diving areas, dive tourism increases.
Where the artificial reefs are composed of semi-familiar objects used in unfamiliar arrangements such as the sub way cars, this has a secondary boost to the dive tourism. There are people sad enough to don rubber head to toe, strap air tanks to their back and spend hours in cold seawater, just to get one of their freinds to take a photgraph of them sitting ina subway car looking as if they are reading a paper. If this opinion offends some, tough, it's actually a quote from my cousin who used to run a dive shool in the Caymans.
Establishing an artificial reef also has benefits in land reclamation as it establishes an offshore hard edge to mitigate erosion of material between the reef and the existing shore.
Finally, an offshore reef has a dramatic effect in reducing the effects of offshore storms on beach front areas, which especially along parts of the US atlantic coast and Gulf of Mexico is a serious concern.
Hope this helps.
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TeachMe,
I may be wrong, but I thing often the main reason is the amount of asbestos in those old ships and subway cars.
That makes dismantling them such a hazardous, hence expensive, undertaking, that it's no longer economical.
Underwater the asbestos in its various forms becomes just a wet cakey mess that does not really disperse in the environment.
CJ
Edit:
Donkey497 got ahead of me, and also gives some perfectly valid reasons, IMHO.
Asbestos is an issue though: you should read up on the saga of the French aircraft carrier Clémenceau....
I may be wrong, but I thing often the main reason is the amount of asbestos in those old ships and subway cars.
That makes dismantling them such a hazardous, hence expensive, undertaking, that it's no longer economical.
Underwater the asbestos in its various forms becomes just a wet cakey mess that does not really disperse in the environment.
CJ
Edit:
Donkey497 got ahead of me, and also gives some perfectly valid reasons, IMHO.
Asbestos is an issue though: you should read up on the saga of the French aircraft carrier Clémenceau....
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And after Dani's post about recycling composites..... a thought....
How soon before we will see nearly-all-composite aircraft, such as the Boeing 797 and Airbus A390, being added to those artificial reefs?
After stripping out ... what? engines, electronics, landing gear, some pumps and generators and flying control actuators, burning the rest is hardly worth the trouble and the pollution and the landfill residue you end up with.
Oh, and what about a photo in seat 4B, with an FA bending over you... "coffee, tea, or me?" all in scuba gear?
Priceless, as they say.
How soon before we will see nearly-all-composite aircraft, such as the Boeing 797 and Airbus A390, being added to those artificial reefs?
After stripping out ... what? engines, electronics, landing gear, some pumps and generators and flying control actuators, burning the rest is hardly worth the trouble and the pollution and the landfill residue you end up with.
Oh, and what about a photo in seat 4B, with an FA bending over you... "coffee, tea, or me?" all in scuba gear?
Priceless, as they say.