[meteorite-list] EBAY Slag for sale

[Randy Korotev]

Sterling:

I didn't know about millerite, and I'm glad to 
know more than I did.  I talked to a colleague 
who knows a lot about Missouri caves.  He's seen 
millerite, but he thinks it's volumetrically 
rare.  His reaction was the same as mine - it's a 
mass-balance problem.  In smelting iron ore a 
given volume of metal would never be exposed to 
enough limestone for the metal get pumped up to 
600 ppm Ni.  Geochemically, nickel is a 
"siderophile" (iron-loving) element, so iron 
metal would take all the nickel from the 
limestone and the millerite it contained.  But 
the limestone would not likely contain more than 
1 ppm Ni, perhaps all carried by millerite.  So 
the metal reduced from the ore would have to be 
exposed to 600+ times its mass in limestone.  I 
don't think that happens.  If the operation was 
also deliberately roasting sulfides, however, it 
probably wouldn't be a problem.

Another colleague asked, tongue in cheek, "How 
much Ni would there be in the metal puddle left 
if you melted a car?"  His point (I think; this 
was over Friday evening beer) was that even a 
modern metal recycling operation would 
occasionally get some nickel-rich metals.

Randy Korotev





At 14:07 06-07-07 Friday, you wrote:

>Hi, Randy, List,

>

>     Starting out with a big disclaimer that this is

>all inexpert speculation, of course, I believe the

>source of nickel in Missouri slag meteor-wrongs

>could be the mineral millerite.

>

>     Smelting is the reduction of iron ores with carbon

>as the reducing agent. Impurities in the ores are

>removed by the addition of a flux, usually limestone.

>In rural Missouri (and anywhere in the Midwest), it's

>pretty safe to say the flux is always limestone.

>

>     The resulting slag will, of course, contain whatever

>was in the limestone, particularly if the material likes

>to combine with iron. Millerite is nickel sulfide, NiS.

>

>     Quoting the Peterson's Rock and Mineral Guide:

>"Millerite is sometimes valued as an ore of nickel

>when present in minor quantities in association with

>other metallic sulfides in middle-temperature veins,

>as in Germany and the massive Sudbury, Ontario,

>sulfide complex. Locally it is sparsely distributed

>through limestones in central Mississippi Valley

>limestone quarries, particularly near St. Louis,

>Missouri, and Keokuk, Iowa. At these places

>long millerite hairs are found in cavities lined

>with crystals of calcite, dolomite, and fluorite. (An

>interesting, if improbable, speculation suggests the

>original source of this nickel might be a heavy

>Paleozoic meteor shower.) Coarser millerite needles

>have been found with hematite in Antwerp, New York,

>and in Alamos, Mexico."

>

>     The use of limestone flux would likely concentrate

>all its nickel in the slag, and you would use more flux

>with poor ores, which are the ones likely to be used

>in a "backwoods" operation.

>

>     Missouri has a lot of  lead/zinc/copper/cobalt/iron

>sulfide ore belts, very extensive but low-grade localized

>deposits, called Olympic Dam deposits. The iron mine

>at Pea Ridge, Missouri, is a known Olympic Dam-type

>ore deposit. It would appear that rural Missouri would

>supply many low-grade local ores with mixed contents.

>(I found lots of references, all far too "geological" for

>me!)

>

>     My half-cent's worth.

>

>

>Sterling K. Webb

>-------------------------------------------------------------------

>----- Original Message -----

>From: "Randy Korotev" <korotev at wustl.edu>

>To: <meteorite-list at meteoritecentral.com>

>Sent: Friday, July 06, 2007 9:52 AM

>Subject: Re: [meteorite-list] EBAY Slag for sale

>

>

>At 14:59 05-07-07 Thursday, STARSANDSCOPES at aol.com wrote:

> >I don't  know why this slag tests positive for nickel, but it does!

>

>

>People have been making iron and disposing of the

>waste for several hundred years in this area and

>much of the US.  The most common kinds of local

>meteorwrong I encounter are hematite nodules -

>iron ore - that weather out of the local

>limestone.  This stuff has been used as feed

>stock for mom-and-pop iron smelting operations in

>the Ozarks since the 1800's.  As Tom Phillips

>said, the processes were not as efficient as

>today, so a lot of iron metal was left

>behind.  People have brought us all kinds of

>glassy stuff with metal in it, one of which even had the imprint of a bolt:

>

>http://meteorites.wustl.edu/meteorwrongs/m026.htm

>

>

>Two months ago a fellow came to my office with

>the ugliest 60-lb chunk of iron I've ever

>seen.  He'd dug it up while "grub hoeing" in

>south St. Louis Co.  There was no smooth surface,

>it was very rusty, and it was full of

>cavities.  It didn't "look like" an iron

>meteorites to me, but I have no experience with

>iron meteorites that have been in the ground for

>100's to 1000's of years, so I really don't know

>what to expect.  In a post 2 months ago, Eric

>Twelker said "Those of us who are lucky enough to

>have hundreds or thousands of meteorites pass

>through our hands possess a store of knowledge

>that has real value to academics that haven¹t had

>this experience."  I agree, and I wish I had that knowledge!

>

>I neglected to get a photo of the thing.  I did a

>quick nickel test, though, with one of those

>nickel allergy test kits and got a positive

>result*.  So, I cut a piece off and analyzed it

>for the Fe, Ni, Co, Au, and Ir.  Strange results:

>

> >Fe   89%

> >Ni  600 ppm

> >Co   62 ppm

> >Ir    1 ppb

> >Au   12 ppb

>

>The object cannot be a meteorite because the

>concentrations of Ni and Co are 100x too low for

>metal in any kind of meteorite.  Yet, the

>concentrations of Ni, Co, Ir, and Au are all

>higher that I would expect for iron smelted from

>iron ore.  More weird is that the relative

>concentrations of those elements (ratios) are not

>out of line for an iron meteorite.  It's as

>though the metal is 1% iron meteorite and 99%

>pure iron.  I don't know what this thing is.

>

>Similarly, a fellow from Colorado sent this photo

>and a small sample a couple of years ago:

>

>http://meteorites.wustl.edu/meteorwrongs/m122.htm

>

>It is also a a man-made piece of iron, but one

>with far more Ni and Co than in any iron oxide ore I've ever analyzed.

>

> >Fe   90%

> >Ni 2590 ppm

> >Co  131 ppm

> >Ir  <14 ppb

> >Au   85 ppb

>

>I don't get it.

>

>Randy Korotev

>

>

>* Note that the dimethyl glyoxime [DMG] test for

>Ni is very sensitive.  If it gives a positive

>result for 600 ppm Ni, then it is too sensitive

>to really be of much use in distinguishing

>meteoritic metal from terrestrial metal. A

>negative result should be helpful, however, if the test is done correctly.)

>

>

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