system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why can't we recycle styrofoam? Seems like it's just a bunch of tiny balls molded together that could easily be reshaped over and over.
gpt
We can recycle styrofoam. There are many producers of styrofoam and other polystyrene products that do accept recycled styrofoam. But there are issues both of transportation and sorting. Firstly sorting different plastics from each other is a very difficult job. Most consumers will just mix different plastics together and even producers will use different plastics in their product making it impossible for consumers to sort on their own. And because different plastics can look so similar it is not something that humans can be able to sort either. This requires dedicated robotic sorting machines that can use various different sensors to differentiate between different plastics and sort it. And although they are coming onto the market now they are very expensive. You might imagine that styrofoam is an exception but there are various different plastics that can be expanded into foam to make something similar to styrofoam but which is made of different plastics then polystyrene. As a twist of fate the recycling efforts of styrofoam have a lot of issues with companies using starch based foams in their packing and promoting it as biodegradable as this will mess up styrofoam recycling when these two very different products gets mixed up.

The other problem is that styrofoam have very low density. So in order to transport it from the sorting plants to the factories that use them you need to use a lot of big trucks which would end up carrying almost no weight. This in itself costs more money then making polystyrene from scratch and releases more green house gasses as well. So by recycling styrofoam you might end up increasing your carbon footprint compared to just burning it for energy. There are some cases where big compacting machines can get the density high enough that transporting it to the factories does make sense but that too is very situational and depends on the distance and the cost of transporting the materials for new polystyrene.