#Earth's Top Elements
31 messages in this thread
What are the top ten *elements* found on the surface of the earth? Is aluminum
or silicon the most abundant?
By <<surface of the earth>>, I mean in the top 50 feet or so, of the land or
sea-floor.
Also, does anybody have the same data for the sea water? I recall, for example
that a cubic meter of sea water contains xx grams of gold, etc.
I am writting a book that holds that minerals are abundant; we need only be
clever enough to know how to extract them.
Dear Bill:
By *volume* percentage, the most common element in the earth's crust is
oxygen. (Believe it or not!)
"Top Ten" element lists are fairly common – you should be able to find
specific data in geochemistry textbooks by Krauskopf or Levinson. Silicon and
aluminum are going to be v. near the top of the column, just under oxygen.
Cheers,
Scott M.
Hi, Bill–
Welcome to the forum!
Numbers I had earlier jotted down from the Encyclopedia Brittanica tell me for
the continental crust (which should be much the same as the top 50 feet) that
the commonest by weight % of oxide (thus oxygen is high on the list, but I do
not know exactly where to place it) are silicon (57%), aluminum (16%),
iron(9%), calcium(7%), magnesium(5%), sodium(3%), potassium(1%), and
titanium(1%). For ocean crust, the order is the same, with silicon less in
proportion (but still 1st) and the others more, while calcium noses out iron
for 3rd.
Many of these are in tight chemical combinations that make them not easily
extracted. Titanium, for example, is common, but not used a lot because it
costs a lot of energy and effort to bust it out of even its best ores. But
given fusion power, dropping ordinary rock into a fusion torch and extracting
even the toughest customers may become easy someday.
–Doug
>> Numbers I had earlier jotted down from the Encyclopedia Brittanica
>> tell me for the continental crust. . . .
Do you remember what section you found that in the Brittanica? I have an
edition in my office and spent some time without success trying to find the
data you quote.
>> Titanium, for example, is common, but not used a lot because it
>> costs a lot of energy and effort to bust it out of even its best
>> ores. But given fusion power, dropping ordinary rock into a
>> fusion torch and extracting even the toughest customers may become
>> easy someday.
Is fusion significant because electricity will be cheap (as in for
electrolysis), or is it because fusion is so hot it decomposes everything? If
that is the case, would not fusion power be the cure-all for *all* mineral
extractions?
Hi, Bill–
Fusion power will almost certainly mean cheap electricity, which is the main
issue when extracting aluminum from its ores. But I was referring to plasma
torches, which can be constructed without fusion power, but require impractical
amounts of energy. They probably can be made via direct and efficient
bleed-off from a fusion reactor. I do not know what further research is needed
to use such torches effectively, but the basic idea is to drop raw rock in to
be vaporized, and use magnetic fields to sort out the elements from that rock.
Common basalt would become an ore of iron, magnesium, etc. This is also a
wonderful answer to waste problems if workable on a large enough scale – I
wonder how much of less common metals are waiting in old landfills? Old
nickel-cadmium batteries, mercury batteries, silver from photos…
Also, solar furnaces may allow much the same vaporize-and-sort treatment for
asteroids, Moon rock, etc.
–Doug
Doug,
You don't need fusion power, of course. ANY source of cheap energy will do for
the processes you mention. What you are pointing out is that the cost of
energy is a multiplier ontop of every single thing that is produced. Generate
energy cheaply enough, and EVERYTHING gets cheaper.
Think back to the Carter Inflation Years – what, exactly, went up in cost?
Energy, of course, dependant on OPEC petroleum. Poor Jimmie got the blame for
the whole mess, and it was only partly his fault.
— Norm
I managed to find the reference of the elemental composition of the earth's
crust in Enclycypaedia Britannica under "Elements, Geochemical Distributions
of."
It lists the parts per million (or percentage) as, for example, Cobolt (25
PPM), Titanium (4,400 PPM), Aluminum (8.1%), etc. Seawater is Gold (1.0x10E-5
PPM) and Silver (3.0x10E-4 PPM). Seawater is also listed at 10.7% Hydrogen and
85.7% Oxygen–which seems odd to me because if the other data is in PPM in the
same table, which would be the number of atoms out of million atoms, I presume;
but the Hydrogen-Oxygen data suggests its by weight or volume, not atom-counts.
Does anyone know how PPMs are defined in this regard?
Anyway, I took this data and wrote the following:
<< . . . the earth is rich in resources; the trick is to know how to get them
out. A cubic mile of backyard dirt, for example, contains enough aluminum to
make a solid cube over 2,200 feet on each edge, and half again as much pure
magnesium. As for "rare strategic metals," with the dirt left over one could
fashion nine Great Pyramids of Giza of pure titanium, and nearly two more of
cobolt. [NOTE: I calculated the Pyramid to be 96.3 million cubic feet.]
Every cubic mile of sea water contains a cubic foot of gold, and nearly four
[actually 3.5] of silver.>>
I'm not sure I agree with my own calculations–especially the one about the
aluminum as it seems pretty massive.
I wonder if there is an error in my intrepreting the PPM (and percentages) as
*by volume* whereas they were probabaly intended to mean *by weight*. If so,
how can I convert the weight data to volume terms?
I can probably look up the specific gravities of the metals somewhere, but it
seems to me that I need to also know the the specific gravity of the earth's
crust? Note that the earth's crust is primarily oxygen (47%), Silicon (28%),
Aluminum (8%), Iron (5%), Calcium (3.6%), Sodium (2.8%), Potassium (2.6%), and
Magnesium (2.1%).
Any thoughts?
Hi, Bill–
Quartz and feldspars have specific gravities around 2.6-2.7, while the darker
rock-forming minerals (more iron) tend to be above 3 – somewhere in between
(say 2.8?) is my guess for the specific gravity of common igneous rocks.
Limestone would be less dense, more like 2.3. "A cubic mile of backyard dirt"
would be somewhere in this ballpark except that it includes a lot of air space.
A cubic mile of solid rock, or a specific weight of dirt might be a more
determinate starting point.
All the percentages in EofB that I looked at were specified as weight
percentages in the table headers; PPM readings may have also been by weight,
and if found in a table specifying weight percentages I would assume as much.
10.7% H and 85.7% O is clearly by weight percent. Volume percentages would
depend on what chemical combination was involved, thus I would be somewhat
surprised to see it used in such a context. Atom counts could be used, but I
would not expect them to be mixed with weight percentages unless this was made
very clear.
–Doug
>> Quartz and feldspars have specific gravities around 2.6-2.7, while
>> the darker rock-forming minerals (more iron) tend to be above 3 –
>> somewhere in between (say 2.8?) is my guess for the specific gravity
>> of common igneous rocks.
Thanks for that important missing data. I think I can look up the specific
gravities of the metals involved, and work it out from this.
Excuse me for being a little abrupt here,
but if you are asking this type of basic question, just where is the rest of
your data/information coming from? I can't help but wonder if you really have
the knowledge to cover the subject.
But your, premise is correct. None (or at least not many) of the basic elements
we really need/use are in short supply in the earth's crust (or atmosphere).
They are just tied up so as to be difficult to gather economically and
ecologically safely. Continual growth in our knowledge does change this, i.e.
up until about the 1950s gold could only be mined if there was greater than
around a half ounce per ton of rock (+ or – depending on the deposit), but now
deposits are being mined that have less than 0.3 ounces per ton.
Lanny
Hi Lanny,
What's wrong with asking a question? I've got 15+ geology books sitting near
me and not one of them can answer that the question that Bill asked.
I was sorta waiting for someone to answer it, myself. I sure wasn't looking
for a put down to a simple question.
Dean
PS. I see you didn't answer his question.
>> I've got 15+ geology books sitting near me and not one of them can
>> answer that the question that Bill asked.
Thanks for the support. I know I've seen a table like the one I'm asking for
somewhere years ago. It's interesting that it's not on page one of typical
geology books, because when it comes down to geology as a tool to build wealth,
the elemental composition of the top layer of the earth is *the single most
important issue*. (O.k., my capitalism is showing.)
I think Lanny might've jumped on the deeper intellectual, procedural aspects of
Bill's question… I re-read his original message several times, tried to find
"the" question, thought he might have already answered it himself by jumping to
the open-ended "answer" of thinking that "all we need to do is figure out how
to extract them", etc. yet Bill said he was already writing a book about the
subject.
If we really want to help Bill and enlighten ourselves, we might have to dig
deeper and declare his first question invalid. What's so special about the top
fifty feet? Is that were oil comes from? No. Is that where most mineral
deposits come from? No. Is that where people of the future will be digging?
Probably not. Even if a nifty fusion torch and elemental mass spectrographic
extraction system were to be developed tomorrow, I'd think you'd get a higher
yield from "mining" a garbage dump than from filtering seawater.
Hi John,
My reading of Bill's original message was that he was looking to extract
commercially useful elements (or materials) without having to mine or "deface"
the Earth. I'm guessing his conjecture was that everything we need for an
advanced industrial society could be available without strip mining.
He may be right. All we need now is a power source.<g>
Dean
It's a common, popular "what if" theme, usually on the tips of the tongue of
fusion (cold or hot 🙂 advocates. It's true, as a "what if", I think…
there's a lot of problems that are solved by cheap energy. I've never heard of
them performing an analysis of how much excess heat would be radiated by these
processes, if everyone had a fusion-powered car-plane, a fusion
water/electricity/hydrogen reactor in every neighborhood, and massive fusion
plants for industry. There's no free lunch.
>> I've never heard of them performing an analysis of how much excess heat
would be radiated by these processes, if everyone had a fusion-powered
car-plane, a fusion water/electricity/hydrogen reactor in every neighborhood,
and massive fusion plants for industry. There's no free lunch.<<
But with "free" energy, we could also pump the heat into hyperhot rocks and
hurl them into space I suppose. I hadn't thought of the problem you pose, but
you're right.
>>What's so special about the top fifty feet? Is that were oil comes from? No.
Is that where most mineral deposits come from? No. Is that where people of
the future will be digging? Probably not. Even if a nifty fusion torch and
elemental mass spectrographic extraction system were to be developed tomorrow,
I'd think you'd get a higher yield from "mining" a garbage dump than from
filtering seawater.<<
Oh, I agree with you. I don't think that the top 50 feet is so special, nor
certainly not seawater. You're right that there are higher concentrations
elsewhere (like the garbage dump), but if I can make my case with standard
backyard dirt, then the case is quite strong that we have unlimited minerals.
To make the case on richer deposits, weakens the argument *somewhat* because it
presupposes unlimited garbage dumps, for example. We already know that the
quantity of seawater and dirt, on the other hand, is nearly unlimited. But
your point is well taken.
Presuming we've got an unlimited energy source for extracting all these
elements, we could be synthesizing them in nuclear reactions, too. 🙂
Doesn't that plan violate a law of thermodynamics? How could you "pump" heat
into rocks without generating more heat? Isn't that like using air conditioners
to cool the planet?
John,
Sure it is. But you -absolutely- can use refrigeration to cool the planet, and
you don't have to toss hot rocks, either. What you have to do is radiate heat
at night. And since radiative losses vary with the fourth power of T, it
doesn't take too awful high a temperature to effectively radiate a big load of
heat.
Of course, it takes energy to accomplish this, so right now, less energy
intensive ways are used, like evaporating water. Unfortunately, such
evaporative cooling towers do NOT take the heat off-planet, and sooner or later
we're going to have to go to a more active cooling cycle.
But there's no thermodynamic violation here – there is no reason at all you
can't use energy to pump more energy against a thermodynamic gradient. The
only requisite is that the -overall- gain of entropy in the waste heat system
is higher than the -overall- loss of energy in the system being cooled. So if
you pump 100 megajoules of heat off planet, the amount of heat actually leaving
has to be higher, say 150 megajoules. I suppose, in limit, you are raising the
temperature of the cosmic background radiation, but I for one am not going to
sweat it.
— norm
I wonder if all those radiators would do a good job of warming the air on
Earth, too, as well as heating deep space.
John,
Well, you have to radiate at a wavelength at which air is mostly transparent.
Moreover, you want to take precautions to insure that the cooling is largely
radiative, without a large convective part. Clearly any scheme will transfer
some heat to air, clouds, etc. However, the schemes we have now transfer heat
largely to air, soil, etc, from which it is reradiated as low entropy heat
radiation. By going to radiative cooling directly, lots less heat will stay on
Earth.
— Norm
>> Doesn't that plan violate a law of thermodynamics? How could you "pump"
heat into rocks without generating more heat? Isn't that like using air
conditioners to cool the planet?<<
Not really. When I want to cool my house I use an air conditioner that "pumps"
the heat to somewhere else. Why can't we pump into into rocks and then throw
away the rocks (into space)? I beleive an air conditioner would cool a house
even if the compressor were physically in the house. All that's important that
the heat radiator not be.
" When I want to cool my house I use an air conditioner that "pumps" the heat
to somewhere else. "
So that explains why it's soooo hot down South! I bet if everyone just would
turn off their air conditioner for a day, temps would return to normal.
<BG>
Michael
>> Excuse me for being a little abrupt here, but if you are asking this >> type
of basic question, just where is the rest of your
>> data/information coming from? I can't help but wonder if you really
>> have the knowledge to cover the subject.
Fair question. I simplified my introductory comments at the start of this
thread. I am actually writting about what I call a "placeless" world in the
21st century. One section on one chapter deals with resources. A number of
journal articles have discussed a popularized debate between Paul Ehrlich (a
population doomsdayer) and Julian Simon (an optimist). Simon posits that
resources are unlimited, and I'm trying to understand the dynamics of that
hypothesis.
>> . . .up until about the 1950s gold could only be mined if there
>> was greater than around a half ounce per ton of rock (+ or –
>> depending on the deposit), but now deposits are being mined that >> have
less than 0.3 ounces per ton.
Good data, thanks.
Hi Bill,
Interesting, good luck with it. Simon may be right about "unlimited" resources
actually existing, but it may be more a matter of semantics rather than
existing in the meaning of being available, which I guess is much of your
premise (hope that mades sense).
Be careful with that "good data" you quote of mine above. First, either you
missquoted it or I made a typo. That should be as low as 0.03 ounces now. Most
of these new low grade open pit gold mines can mine at 0.1 ounce and as low as
0.03 ounces per ton (as in around $10-11 per ton value), and there are a few
down below that. Also, the figure of around a half ounce up to about the 1950s
is very general. It depends on the decade (war time, worldwide recession,
etc.), as well as a lot of economic factors.
Lanny
<<First, either you missquoted it or I made a typo. That should be as low as
0.03 ounces now>>
Oh that's a *big* difference, and I'm glad you caught that. I thought before
that to go from .5 to .3 was *good*. But to go from .5 to .03 is *tremendous*.
What a difference; it makes the example even stronger.
>> . . . up until about the 1950s gold could only be mined if there >> was
greater than around a half ounce per ton of rock (+ or –
>> depending on the deposit), but now deposits are being mined that >> have
less than 0.3 ounces per ton.
Are there any other examples of such effecienciy gains that come to mind,
perhaps in other minerals?
Bill,
(for anyone reading this message and not the previous one: my figure for the
present day gold grade was as low as 0.03 ounces)
There are lots of them. Generally most metals can be mined at a lower grade
because of improvements in mining techniques and milling/metallurgy processes.
Of course this has to be balanced with the increasing costs of labor,
environmental concerns, etc. I am not a good source for statistics on these, I
don't work in mining geology anymore.
Contact the US Bureau of Mines.
Lanny
Lanny R. Ream:
Concerning your comments about the progress we've made on gold processing, I've
used your data in my book and would like to quote you as a reference. If you
are agreeable, I could make use of your title and professional affiliation
(which you can send by direct E-Mail if you prefer).
The book should come out in Fall '96 called THE PLACELESS SOCIETY.
For your interest, following is the full text (rough draft) of the relevant
section:
. . . . [Technology brings prices down.] For example, in the early
1800s, the primary lamp oil came from whale oil, which was relatively
expensive. Then in 1855, Benjamin Silliman, a Yale chemist, showed the world
how to distill oil rock into kerosene, which provided a much brighter flame at
a lower cost than whale oil. And more
importantly, Silliman's discovery converted what was formerly
just a black gunk that ruined farmland into a usable resource.
Within a decade, the first surface oil well was drilled in
Pennsylvania to 70 feet, but by the 1950s, rotary drills were
developing which today allow drilling to a depths of 25,000
feet or more. At the same time, we have made tremendous
strides in using seismographic echo, gravity-meter and
satellite data, hooked into supercomputers, to actually predict
where the oil can be found. With each development, our
ability to squeeze oil out of the earth expands. It is
technology that has allowed our known reserves of fossil fuels
to continually expand over the past century, despite ever-
increasing consumption.
[THIS IS YOUR PART:]
Another excellent example is gold. Until the 1950s
gold ore had to have greater than half an ounce of gold per
ton of ore to make mining worthwhile. Anything less was just
not "ore." Yet today we routinely mine ore at less than half
that concentration, considerably expanding both the our
known reserves and the world's output. And the gold rush
not anywhere but over. . .
We are just learning how to process pure gold from
pyrite–the legendary "fool's gold" that prospectors for
centuries learned to toss aside. Scientists have discovered a
bacteria that eats sulphur and iron like so many termites,
leaving behind a residue of concentrated gold dust. The
same process may also prove handy to convert acid-rain-
producing high-sulphur coal, into pure carbon cubes. In time,
"biometallurgists" may be able may be able to develop
designer-bacteria to make rare metals from raw dirt, just as
we use bacteria today to make cheese, beer and yogurt from
raw agricultural inputs.
Thanks.
Bill,
Quite interesting, and in general I like what you wrote here. One thing though,
I don't think the words "actually predict" are quite right in looking for oil,
or ore deposits either. There still are a lot more misses than hits.
Thanks for the interest in my stated facts, but as stated in the previous
question, I am not the best source of any of this information. (Also your
statement is not correct after you change my present day gold grade down to
less than 0.1 ounce and as low as 0.3 (and lower). That puts it commonly at
less than 1/10th of what was commonly mined in the past.
Anyway, try the US Bureau of Mines (Washington DC) for better statistics.
Lanny