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282 points antidnan | 2 comments | | HN request time: 0.013s | source
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_heimdall ◴[] No.41919400[source]
Well I guess this is a good win for short term energy infrastructure, though I'm always pretty torn when its at the cost of ripping open huge swaths of earth to get at the raw material.

It is interesting to see how much of this data could be modelled based on wastewater brines from other industries in the area, assuming we go on to mine the lithium it will say a lot if the ML predictions prove accurate.

One thing I couldn't tell, and its probably just a limitation of how much time I could spend reading the source paper, is what method would be needed to extract the bulk of the lithium expected to be there. If processing brine water is sufficient that may be easier to control externalities than if they have to strip mine and get all the overburden out of the way first.

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jofer ◴[] No.41919627[source]
You physically can't remove the overburden for this. The Smackover is at a depth of multiple kilometers in most of these areas.

It's mining brine. I.e. the "mines" are basically deep water wells.

The limestone itself doesn't have any lithium. It's the water in the pores in the limestone that is relatively concentrated in lithium.

In most of these cases, you're already producing brines from the smackover formation as a part of existing oil and gas production, but the brine is being re-injecting after oil is separated from it. The idea is that it's better to keep those and evaporate them down for lithium production.

That does require large evaporation ponds, generally speaking, but it's not strip mining.

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_heimdall ◴[] No.41919842[source]
Extremely helpful, thanks for the extra detail here. I have a background in the oil industry and live in a region strip mined for coal (I actually can't tap a useful ground well because of it), but I don't know much about how lithium is actually extracted.

As far as evap ponds go, are there usually chemicals or elements in the same brine water as lithium that is important when evaporating into the atmosphere?

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1. jofer ◴[] No.41920767{3}[source]
There are a lot of things in deep subsurface brine. It really varies.

First and foremost, here are definitely lots of other salts. It is brine, after all. You produce a lot of halite (salt), gypsum, calcite, and all kinds of other evaporite minerals.

There are all kinds of things in smaller concentrations, though.

What comes out of a oil/water separator would need lots of additional processing before going to something like an evap pond. It's relatively hazardous stuff for a lot of reasons other than oil (e.g. it can be rather radioactive). It typically goes through quite a bit of additional processing unless it's being immediately reinjected.

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2. lazide ◴[] No.41921278[source]
Yeah, underground brine is rarely nice to be around, especially when concentrated, but does often have a lot of useful minerals. Related facts, I’m guessing.