In Switzerland, in some Cantons, there is a trash tax. You pay roughly 1-2 USD the small taxed trash bag. So at the current trend it will literally become cost efficient to send our trash to space in a few years.
The advantage of re-using slag isn’t that it’s richer in metal, iron oxides being pretty easy to get, it’s that it would take less energy or Oxygen to finish refining.
Recommended reading: Bret Devereaux’s blog series about iron & steel production. https://acoup.blog/2020/09/18/collections-iron-how-did-they-...
That or slag is much lighter per lb of refined product, reducing the transit cost. Iron ores are incredibly common, but they’re also very heavy, what with them being literally rocks.
If you search on YouTube for "deskulling slag pot", you'll find a bunch of videos showing slag trains going maybe a couple miles from the mill to a pit to deskull?
Only about a quarter of « new » silver comes from silver mines. The rest as a byproduct of other mineral mining where they separate out the silver.
My understanding for why we don't use those for spacecraft is because people and fine machinery can't take the Gs.
Trash could.
Rockets have a huge advantage in that they go slow near the ground, where the atmosphere is thick. They're not dealing with as much air resistance. As they reach altitudes with less atmosphere, they can throttle up. This saves a lot of fuel, mass, energy.
A rail gun, however, can only add velocity, energy, at the beginning, and will slow down every moment for the rest of the launch. This is the worst possible condition. You're at your highest velocity while you're in the thickest part of the atmosphere. You'd need to put an incredible amount of extra energy into the system because of that.
So maybe you put the end of your rail gun on the top of a very high mountain. But the construction costs, the transportation costs, all of this, probably makes it simpler to just use rockets instead.
https://en.wikipedia.org/wiki/Project_HARP
https://en.wikipedia.org/wiki/Project_Babylon
[Edit] Also the German V-3. An important note is that the V3 and Babylon (unsure of HARP) were designed to have multiple charges go off as the projectile proceeded down the barrel, which gives an acceleration profile more like a railgun than a traditional cannon.
https://en.wikipedia.org/wiki/V-3_cannon
Solid-fuel rocket boosters were used instead of explosive charges because of their greater suitability and ease of use. These were arranged in symmetrical pairs along the length of the barrel, angled to project their thrust against the base of the projectile as it passed. This layout spawned the German codename Tausendfüßler ("millipede").
1: https://en.wikipedia.org/wiki/Asteroid_mining#Proposed_minin...
It might happen for other reasons like remediation or whatever.
In a modern landfill it already gets recovered (there's a liner underneath, so they have to have a way of dealing with water).
Trash disposal here is great; free unlimited household trash disposal if you drive it to a dump, with only larger things like tires and mattresses costing money (but a very reasonable amount, like $2/tire).
Hold up.. This not only varies by state, but by county and city. Some places have this built in to special assessments on property taxes, some contract with a trash company that collects fees directly, and some are a bit of a free for all with multiple trash companies providing pickup and or/dumpster service (this is more common in rural areas).
I had a place up in the mountains where we had to buy special $6 trash bags and haul it to a central dumpster ourselves, and there are those in large cities who have to deal with mob-run collection companies who bribe local politicians for monopoly rights.
TLDR; To generalize "In the USA" for something like this is impossible.
One approach is to capture a number of related issues in one fee at a natural point of contact that is easy to measure. It's not a crazy idea.