Feasability of plasma based garbage recycling into pure constituent elements

Is it possible to build a garbage recycler that turns residues into its constituent elements using plasma and accelerating it through a magnetic field?

The technology level is around that of the typical space opera: starfaring civilizations. Physics and chemistry are the same as ours.

Energy input and disposal is not a concern (we could include a fusion plant or ten to the project, but we do not have unlimited power!).
This is a space based recycler, so hard vacuum is easy to access, but there can be atmosphere artificially provided if necessary. Resting frame of reference.

The material to be recycled is frozen (few Kelvins) compacted heterogeneous mixes of waste in 10m sided cubes (in the order of tens of thousands of tons). The cubes are covered in a film that prevents out-gassing and keeps any elements or composites that manage to be liquid at the said temperature. Encompassing everything from paper sheets and fish poo to shredded nuclear reactors, cars and solid blocks of reinforced concrete. The blocks can have any element of the periodic table, and all of them are to be expected in any proportion, including all useful alloys, compounds, organics and textiles ever known.

The film can be of any material, though it's planned to be a carbon-based polymer of some sorts. It can be removed from the cube prior to process if necessary. The cube can be made smaller or even shredded if required by the process, but bigger chunks are never going to be provided. If it needs to be made into dust/fine particles, the "atomization" process should be part of the recycler. If the mix needs to be preheated, it will also be part of the process.

There should be no expectation that the mixture has the same proportions of element rarity present in the universe or Earth's crust.

Noble gasses and the most heavy and radioactive elements can be mixed at the end of the process, if it's too hard to differentiate them. PREFERABLY NOT!

It can be an expensive piece of infrastructure: it's meant as a one of a kind per heavy populated star system (in the order of 10^7 citizens). Its purpose is to be the end step of traditional recycling process leftovers.

It's located in space, it can be near the main star or well past the ice giant portion of a star system, wherever you need it.

Size is also not a concern. Single structure designs are preferred over "distributed" infrastructure, for defense purposes, but will do what's necessary. Should be less massive than a little moon (10^19kg).

It does not need to be practical. It's meant as a "safeguard" against interstellar resource blockades (like subsidized agriculture in some countries).

It need outputs in the magnitudes proposed to be able to keep up with demand during wartime on systems whose planets do not have enough tectonic activity to produce veins of vital heavy metals and elements.

During peacetime it's used to just simply complete a loop of resources in space where necessary, maintained by deep space dwellers to avoid being captives of planet surface inhabitants.

As strategic infrastructure, its existence comes first. More productivity and more efficiency are the secondary really important points, and economic sense is the third concern, but some systems need one to be anything else than colonies.

Previous research and ideas

http://www.inentec.com/pem-facilities/

https://www.explainthatstuff.com/plasma-arc-recycling.html

I've envisioned a toroidal fusion power plant that is fed a stream of fine grained garbage along with the usual fusion fuel. The stream would get turned into plasma and then ejected to a magnetic accelerator that uses atomic weight and magnetic fields on the curves of a loop to separate the stream into its constituent atoms in separate receptors.

Is this or another design feasible?

How does it work?

Synchrotron, the shape that resembles the proposed design

Bonus points:

• Approximate volumetric size of the plant (capable of processing 1 cube per day)
• The order of magnitude of energy or fuel consumed or produced (for any fusion or other kind of reaction(s) you choose for the process)
• How well does it scale (up and/or down)
• Containment method for the elemental outputs

EDIT

Based on answers, it seems clear that mass is really relevant to the segregation process. Please, feel free to include a centrifuge or whatever you come up with to use mass to your advantage.