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Newsgroups: sci.environment,talk.environment,aus.politics,
Subject: Re: If it take more energy to mine
From: (Paul D. Farrar)
Date: Tue, 04 Mar 1997 07:37:00 GMT

On Mon, 03 Mar 1997 03:18:35 GMT, (Paul F.
Dietz) wrote:

>JoshuaHalpern <jbh@IDT.NET> wrote:
>>: I believe there is a net energy gain in extracting uranium from
>>: seawater even if breeder reactors are not used.
>>That I would seriously doubt.  At best this should be
>>sensitive to the extraction method, and/or the ability
>>to concentrate the sea water into a mineral rich
>Uranium would not be extracted from seawater by concentration
>of the seawater into a brine.  Rather, it would involve suspension
>of special resins in the ocean in a region of strong currents.  The
>resins in question (polyamidoximes) strongly bind uranyl ions in
>preference to other positive ions.  After several months, the resin
>would be recovered, the uranium eluted with bicarbonate or acid
>solution, and the resin returned to the ocean.  The resins in question
>can accumulate a significant fraction of their own mass in uranium
>while in the ocean.

How much can it accumulate if it, all its pores, and its supporting
structure are covered with algae, barnacles, bryozoans, sponges, with
little crabs running around on top? Most of the Boundless Energy
[Minerals] from the Sea scenarios I've heard of -- wave energy, OTEC
etc -- run afoul, ... literally,  of the actual marine environment. My
friends sit around swapping stories of the gear lost; smashed by
waves; trawled up by fisherman; vandalized by trawlermen mad about the
last net they lost; shot up by drunken rednecks; stolen for the
floats, anchors and cables; you name it. (Just don't try it, several
thieves have gotten caught because they didn't know the telemetry
devices would lead the owners right to them.)

Ship time for putting out and recovery runs about $20,000/day, but
that depends, in part, on low petroleum prices for the fuel. It's
fairly dangerous work, too. Unless it's very expensive, most moored
equipment just gets left out when it malfunctions, until a
ship-of-opportunity can stop by.

Nonetheless, the chemical oceanography literature I've seen does
dangle the possibility of an energy break-even (though I haven't seen
that for moored collectors), with breeding and with absorption of
other valuable ions, like gold.

>This technique is not currently competitive with conventionally
>mined uranium.
>	Paul

Another Paul
Paul D. Farrar

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