As we know the nature pit crusher was replaced with something more effective in a previous update with the pit itself moved to the outside of the facility. The same should be done with the volcano pit, not removing it entirely it will be relocated and put in a new small volcano added to the island.
The recycler will be basically a giant furnace, the vehicles rolls down the conveyor into the furnace which is full of lava that will instantly burn up the vehicle and melt it and then gets pumped back out on a small conveyor next to the furnace as small bricks of aluminum, steel and other metals.
images of incinerators and furnaces for concept
