Here are my references, in chronological order:
[1] The thermal decomposition of lithium aluminum hydride, Garner & Haycock
(1951)
http://rspa.royalsocietypublishing.org/content/royprsa/211/1106/335.full.pdf
[2] PRELIMINARY INVESTIGATION OF LITHIUM HYDRIDE AS A HIGH-TEMPERATURE INTERNAL
COOLANT, Modisette (1957)
http://naca.central.cranfield.ac.uk/reports/1957/naca-rm-l57f12a.pdf
[3] INVESTIGATION OF LITHIUM HYDRIDE AND MAGNESIUM AS HIGH-TEMPERATURE INTERNAL
COOLANTS WITH SEVERAL SKIN MATERIALS, Modisette (1958)
http://digital.library.unt.edu/ark:/67531/metadc53069/m2/1/high_res_d/19660024045.pdf
[4] The Thermal Decomposition of Lithium Aluminum Hydride, Block & Gray (1964)
http://pubs.acs.org/doi/pdf/10.1021/ic50025a009
[5] Desorption of LiAlH4 with Ti- and V-based additives, Blanchard, Brinks,
Hauback & Norby (2004)
http://www.sciencedirect.com/science/article/pii/S0921510703005415
[6] Hydrogen, lithium, and lithium hydride production, US 20130047789 A1 (2013)
http://www.google.com/patents/US20130047789
Notes
- [1] is the classic paper (1951) everyone seems to refer to.
- [2] is prelim of [3], with slightly different content, describing the
reversible LiH decomposition reaction
- [4] if this isn’t referenced in any paper regarding LiAlH4 Thermal
Decomposition, the paper is suspect (1964, 2 pages, but unfortunately behind a
pay wall, maybe if someone searches hard enough, they’ll find it; I’ll look
after I post this. Has DSC Plots, breaking down the H2 Evolution at various
temps, but at standard pressures)
- [5] Behind a pay wall, but what you see on the page is good enough... The do
NOT reference [4]!
- [6] Some nice Vapor Pressure curves in here!
- I also came across this book via the Internet (as well as Axil), but I do not
have it (looks very useful):
http://www.bookmantraa.com/thermophysical-properties-lithium-hydride-deuteride-tritide-their-solutions-with-lithium-book-72683.html
- Mark Jurich
From: Mark Jurich
Sent: Saturday, January 03, 2015 11:56 AM
To: [email protected]
Subject: Re: [Vo]:Right-on AGP
Hi Jones:
Without going into all the details, your calculations are in line with the
language-translated Parkhomov information. At the point of estimating the
corrected pressure due to heating, he simply multiplies the 50 bar/atmosphere
pressure by 2, to obtain 100 atmospheres. I’m not sure where you obtained the
900 °K value for the temperature, but all current estimates are that the
internal temperature for the Parkhomov Cell is no more than about 1000 °C
(probably lower than this), based on where his thermocouple was located. His
plots approach 1300 °C where he was measuring at...
... Crunching through all the possible numbers, I get a top end of 3425psi
using all the “extreme” values. Since the MFMP DogBone has Stainless Steel
extension on it, the volume has now increased and I would be making a wild
guess at the added volume, but I would say 30% more (perhaps Bob H./MFMP can
give us some more accurate estimate)?
I believe Parkhomov is assuming [virtual] loss/leaking of H2 when obtaining
his factor of 2 pressure increase with temperature (and perhaps it has
something to do with the equilibrium conditions that will be obtained when the
2LiH <> 2Li + H2 reversible reaction occurs at the temperatures/pressures
involved. But this is all pure speculation on my part, since there are no
remarks that I can find. Please note that Parkhomov had no way of knowing the
actual pressures, since he did not measure them, as far as I know...
... He does refer to “> 850 °C” for the above reversible reaction, but I
believe he obtained this value from the Boiling Point of LiH (850 °C) at
Standard Pressure. Actually LiH starts to decompose before it boils (according
to some literature), so for anyone to mention the Boiling Point of LiH (as I
have just did), is highly questionable. Other sources say that decomposition
occurs from 900 – 1000 °C, with no solid reference that I can find to back it
up...
... I have about 5 references here concerning all this, and will try to post
them when I get more time...
- Mark Jurich
From: Jones Beene
Sent: Saturday, January 03, 2015 9:40 AM
To: [email protected]
Subject: [Vo]:Right-on AGP
Has anyone determined that the high internal pressure claimed by Parkhomov is
even possible? Did he claim 500 psi? I cannot find the reference today, but the
numbers are probably out there and at first glance – score one for AGP.
Btw – in a search of Vortex, it turns out Parkhomov was mention by Rothwell way
back in 2012: Author: Y. Bazhutov … A. Parkhomov et al, Year of Conference:
2012 Title: “Investigation of Radiation Effects at Loading Ni, Be and LaNi5 by
Hydrogen”. Very appropriate.
Just in case no one else has done it– here are back of envelope calcs –
rounding off slightly: molar volume of hydrogen gas (assuming ideal gas at 1
atmosphere of pressure) is 24.5 liters (or dm3/mol) at 300 °K, and the weight
of a mole is two grams, so this gives 12 cc/mg for H2 at one bar and ambient -
or 36 cc/mg at 900 °K elevated temperature.
The “fuel” of Parkhomov was said to be 1/10 gram of LiAlH4 which is about 10%
by weight hydrogen. This means that the weight of hydrogen, if none escapes is
about 10 milligrams at the start. This means that the expanded gas would occupy
about ~120 cc at STP, if released from the hydride - correct?
OK. The interior volume of the reactor appears to be about 2.4 cc. so cramming
120 cc into 2.4 means that would require about 50-1 ratio... or 50 bar BUT if
the reactor and gas is at 900 °K, then 150 bar or 2,175 pounds per square inch
is possible. So the bottom line is yes, even with slight diffusion into the
alumina and no leaks, 500 psi is not only possible but on the low side. The
important detail is what is the pressure at 10,20,30 hours and so on?
Apologies if this has been covered, or is not accurate but a lot of folks seem
to second-guessing AGP, at least on a few points, and there appears to be no
problem on this one.
As of now, in terms of “trustworthiness” of reported data, based on past work,
openness, and freedom from an agenda which would cause one to fudge data or
salt the ash to be tested - I would give AGP a much higher ranking than AR.
Let’s hope we get isotope data. This reaction is nearing the level of
understanding.
Jones
