Separation of PVC from Aluminum

Coated with aluminum foil?

This phrase does not point to a coating but a lamination. If it is put together in a mechanical way, think of separation mechanically.

If it has been damped of put together in a galvanic way, you can reverse this by chemical means, with or without electric assistance.

Further, both materials have different characteristic as temperatures of plasticity and/or melting and also specific density.

On what you communicate we have about nothing specific to help you further, although there might be several ways out.

Start with the thickness of your aluminum and the nature of your products.

Scrap is about anything possible.

PVC is pretty good recyclable: one suggestion could be to feed the product in a thermo feeder (2 screw type), where the PVC melts and the aluminum can be stopped by a seeve (that you 'll need to clean).

You probably need to shred your stock to a usable size before.

Other processes will use a lot of heat and or chemicals and are more problematic to the environment.

Thanks. for apt guidance. I will try your formula n approach back. nice suggestion.

there may be no economic way to recover these materials. This is expecially true if they are thin = the juice box problem, in which several layers are laminated.

They mince those in water.

juice box recovery

Something similar might work for you. Sadly, with only 2 tons = not worth the effort.

The recovered plastic is worth 50 cents per pound. 90-95% of weight is plastic.

the aluminium is also worth about 50 cents.

You might look for companies who have solved this problem in your area who will buy your waste as their feedstock.

Dissolve the Al coating then recover it from solution.

Aluminum dissolves easily in caustic soda solution to form sodium aluminate plus hydrogen (care!). The PVC will be unaffected. So you can reclaim the PVC, but you have lost the aluminum.

The reaction between aluminium and caustic soda is highly exothermic, nay, explosive under the wrong circumstances!

Dissolution in some weak acid followed by electrolysis to recover the aluminium might be a better route, however, the economics of it would bear careful scrutiny before starting.

The original poster would do well to engage a Process Engineer to solve this problem.

I suspect that selective heat exposure might work if the aluminum is thick enough. Just heat up a local section (passing through the machine) and scrape off the aluminum from the softened plastic? Then you have a bigger mess to play with?

Seriously? Use the new aluminum battery technology with the aluminum side being an energy donor/anode. The charge carrier takes care of the rest. Use the energy produced to replate out the Aluminum (after transferring some of the AlCl4 anion) to another cell's anode in the charging cycle.

Result: clean metallic aluminum separated from cleaned PVC.

Maybe some sort of acid bath could strip the aluminum and precipitate it out in a recoverable way.

Al dissolves in HCl and H2SO4 giving the salts which could be recovered by evaporation or precipitated by adding a phosphate solution, Al phosphate being insoluble. Recovering Al metal from any of these salts would require the high temperature electrolysis of the molten salt, just as in the Al manufacturing process. The amount of energy would be ridiculously high, as would the cost of the apparatus required. You can forget that idea.

Sodium hydroxide(NaOH)known as Lye, will dissolve aluminum....producing hydrogen gas...

https://www.youtube.com/watch?v=6B6Q5fgE9qo

Wacko demo....

https://www.youtube.com/watch?v=AngMiOBrHnQ

I suspect this recovery will not be economic. It might have to be driven by environmental concerns, with money consumed and no product to sell.

It might be possible to mince to a fine state, then dilute with a solvent(which might be an exotoic solvet) to allow the minced aluminum to be filtered out. Afterwards the solvent is driven off by heat in a vaccuum and recoverd by condensation.

Odd spellings.

It was an exotic spelling...

If you want cheap, lay it out on the beach for a while....just not my beach...lol

First- Contact a plastics recycler and see if they are interested in it either as is or ground into small pieces. They may have a customer who wants exactly what you have. That would certainly be a cheaper way of handling the situation, even if you paid them to take it away. Don't stop with the local outfits, go nationwide with your search. If they must have it ground there a plenty of small plastics shops who will do it at a reasonable cost. Certainly a lot cheaper than the chemicals ways.

Problems with chemical are the size and configuration of the pieces. It they are large or have unusual dimensions it will take a big "tank, tub" to contain this process. The bigger the tub the larger the amount of chemicals needed to submerge the plastics to get them in contact with the chemicals.

If nothing else is possible: soak them in 20% sodium hydroxide with slow to moderate agitation of the solution; drain the solution and rinse the plastics with water; recover the water and place it in with the drained solution. Neutralize the solution with weak hydrochloric acid to a pH of 7.0. Filter out the metallic aluminum and discard the resultant sodium chloride (table salt) solution in an environmentally approved manner (probably put it down the sink).

Good Luck, Old Salt

"Filter out the metallic aluminum" There is no metallic aluminum after dissolving it in sodium hydroxide - it's all present as sodium aluminate (NaAlO2).

I have 'cleaned' a stainless steel sink by placing a sheet of aluminium foil in it overnight. I noticed that the Al foil was eaten up in the process. So it may be possible to simply put it all in a large stainless steel tank and fill with water and watch the Al strip away.

Any one else know what happens here? Is it safe?

Jim

You can try soaking the PVC with Al film in the chemicals used for chemical milling of Aluminium parts of aircraft called leaching. I think it is some strength of Sodium Hydroxide; you can establish the process in a lab in beakers and then apply by scaling up; PVC will get separated but aluminium is lost as compound in the solution

I once saw plans for a waste treatment using molten sodium carbonate. If you tried that you could rest assured a clean separation, and lots of off-gass to process and burn away.