# Is it possible to break any given matter down into protons, neutrons, and electrons and then reorganize those particles into any other form of matter?

I was reading about this somewhere but can't find the site now. It was talking about using 3d printers in the future that can intake any matter (dirt, garbage, etc..) and deconstruct it on the atomic level down to just electrons, protons, and neutrons and then use those left over subatomic particles to create anything by rearranging those particles into the needed formation for whatever it is you want to make. This would surely have a huge impact on the way we live since you'd be able to use your own human waste for example to make anything you'd want as long as there were enough particles. But is this theoretically possible?

• The universe started with hydrogen and some helium and has made everything else out of it, so yes, it is. Unfortunately in order to do this on large scales for heavy elements you really need supernovae, which are not very practical objects in engineering terms. – tfb May 5 '18 at 9:06

The nuclear case is exactly the same. You can photodissociate $^{56}$Fe into 13 alpha particles and 3 neutrons by hitting the nucleus with 124MeV photons; by heating matter nuclei to $10^{10}$ K it can hence be converted into free nucleons and alpha particles that can then in principle be separated, cooled, and fused into other isotopes with a total energy cost/gain depending on differences in binding energy. The thermodynamics looks the same: you will have to pay a minimum cost around 5 kJ/mole of nucleons just to separate the types and most likely pay a huge cost for the whole process.
If you have the wrong number of nucleons you could go even higher to the Hagedorn temperature $2\times 10^{12}$ K where baryonic matter "melts" and get newly minted particles out of the quark plasma, but this will likely waste a lot of it as uncatchable particles like neutrinos or anti-leptons left after pion decay (when you get antimatter as a waste product it is a hint that you are doing something wrong!)