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Comment by justinator | Hacker News Reader

Glass is a terrible material in a recycling sense, as it's weight makes transport costly and wasteful (fuel). The raw material is essentially sand (silica) which we're not going to run out of, soon. Burying it in a landfill won't make a worst landfill - it's essentially inert.

It's literally better to NOT recycle glass than to recycle it. Reuse it.

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The #1 ingredient in glass isn't sand, it's previously manufactured glass. You can pretend it's sand, but it's not.

The economics of all this is very geographically dependent.

In many parts of the country, the transport cost isn't a big deal because there are glass manufacturers who use cullet nearby. It's not clearly superior to transport glass to a landfill instead of a place that can recycle it.

Glass recycling isn't economical enough to reuse brown bottles in Montana? Understandable - so it's not collected.

Saying that glass recycling is economically and ecologically unsustainable everywhere is a bold statement.

I don't understand why it's better to not recycle glass. Yes transporting used glass is costly, but isn't collecting and transporting sand even more costly? And while we won't run out of sand, good sand is limited. Or can you use any sort of sand to produce glass instead of a specific type of sand? Doesn't refining sand into glass take additional energy compared to melting existing glass?

For one truck load, how much sand can you carry per volume, vs. old glass bottles? For the latter, aren't you mostly transporting air?

You don't want to BREAK the glass bottles, since they still need to be sorted, and cleaned.

Do you know what you are talking about?

I am far from an expert, but here in germany glas gets recycled in 3 bins, brown, green, white - and get usually smashed by people throwing those bottles in. So not much air. And cleaned they still can get (and should)

Germany is quite ahead of the curve when it comes to recycling.

Here in Boulder, CO, USA, recycling goes only into one bin. It then needs to get sorted at the recycling center. We're told not to smash bottles. Glass has to first be sorted by color.

Also we have nothing at all like the Pfand system. I pay for the privilege to have recycling taken away, not the other way around. What Germany has is awesome.

It's easier to sort broken glass cullet than bottles.[1]

The actual sorting step scans each small piece of glass cullet individually, and air jets kick different types into different outlets. This is very fast - 30 metric tons an hour.

[1] https://www.youtube.com/watch?v=GkILrp11Jq0

Depending on which kind is used to make glass, we actually are running out of sand.

https://www.newyorker.com/magazine/2017/05/29/the-world-is-r...

http://www.businessinsider.com/world-running-out-sand-resour...

From the first article, "In some applications, natural aggregate can be replaced by or supplemented with recycled materials, but the possibilities are limited. "

It doesn't go on to why that is, but the conclusion is that recyclable glass won't work(?).

The problem, if i remember correctly, is that you cannot control the purity of recycled glass very well. The last time I checked it was mostly used to lower the temperature needed for the furnace.

But if you want to make pure boro-silicate glass, you cannot tolerate much contamination of oxides, lime, lead, dolomite, salt, etc. or your glass will be tinted, full of bubbles, and possibly even cracks while cooling.

Even with the recycling system in Germany where you separate glass by color, people will not distinguish a soda-lime, boro-silicate, or lead glass. And I don't know a process that could extract the pure SiO2 from old glass (though I'd love for someone to jump in and tell me about a cheap method)

That's surprising to me. By not recycling glass you pay the fuel costs to move that glass to a landfill and you pay the fuel costs to move sand to your glass production facility.

Is the final cost lower just because landfills and sand are everywhere, but recycling facilities are farther away?

I think there's a lot of things to juggle around when trying to figure it out. Here's one situation, though:

What's more dense in material: a 10" by 4' by 4' pallet of old jugs, or a 10" by 4' by 4' pallet of sand?

I'm saying the latter - we're essentially shipping air as the majority of the material. So, more trucks need to ship the same amount of material.

That's just one example.

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