Quite a bit of paper / cardboard as well for much the same reason.
What waste is actually recycled in Australia?Aluminum
Only a fraction of energy goes Into melting down waste aluminum (to make new products) compared to manufacturing aluminum from raw minerals.
But how much aluminium ends up In landfill due to people discarding It without a thought of recycling It ?
As already mentioned by other posters there is quite a bit of plastic recycling done here for things like Tomato stakes, part benches, decking etc but no where near enough to make a dent in the plastic mountain.
Glass packaging (i.e soda-lime glass) is recycled in Australia, but the glass making process can't use 100% recycled glass as feedstock - 70% is about the limit, the balance being new materials (sand, soda ash, limestone etc). The mountains of glass issue that was on 4 Corners last year is partly a result of how heavily contaminated the glass waste-stream is.
Scrap steel is domestically recycled as well. Electric arc furnace mini-mills use scrap steel as their primary feedstock. It's a reasonably large part
of Liberty OneSteel's business, for instance - they have 4 mini-mills in Australia.
All things considered, plastic recycling is a small niche at the moment compared to aluminium, steel, paper and glass recycling. With enough end-product demand and a good clean feedstock stream it could get much, much larger - but it costs money. Recycled sleeper production could absolutely dwarf other recycled plastic production if there was good take-up from the rail industry - but the rail industry needs a really high quality product (and probably some direction, regulation, subsidies etc from Governments) to justify that.