Monday, March 24, 2008

A sulfur-free Silicon Thermite

Many a backyard scientist has experimented with thermite reactions, including one of the harder reactions, that of silicon dioxide (silica, SiO2) and aluminium (Al) to produce silicon metal(loid) and alumina. These reactions present great pyrotechnical displays and with a little luck leave you with some lumps of metal as a memento. Because of the metal produced, thermite reactions also find widespread use in aluminothermic metal extraction processes for the preparation of specialist high purity metals and alloys.

Although the reaction 3 SiO2 + 4 Al ---> 3 Si + 2 Al2O3 is thermodynamically favourable, this reaction does not propagate by itself, presumably because the heat of reaction isn't enough to overcome the activation energy it needs. Straight mixes of a silica source and aluminium powder therefore fizzle out or can't be ignited.

To make the reaction self-sustainable, the most used method by backyard scientists (and fellow travellers) is to add a booster mix of aluminium powder and sulfur, which reacts according to 2 Al + 3 S ---> Al2S3 with great development of heat with great development of heat (ΔH ≈ -5.3 kJ/g of stoichiometric mix). This heat provides the missing activation energy and makes the reduction of silica to silicon with Al self-sustaining.

A typical sulfur boosted silicon thermite mixture is silica/Al/S = 100/111/133 (9:10:12) but I've also successfully used mixes much lower in S, such as 100/72/21.

Apart from yielding a self-sustaining reaction, S-boosted silicon thermites have also other advantages:

• Quite easy to ignite, using magnesium (Mg) ribbon (e.g.).
• The resulting slag is a mix of alumina and aluminium sulfide (Al2S3). The much lower MP of the sulfide (around 1,100 C) causes the slag mix to be more fluid than pure alumina, which freezes at around 2,000 C. This greatly helps slag/metal separation, as the slag/metal mix remains liquid longer, allowing it to collect in the bottom of the crucible and the metal to coalesce out. And a mix of alumina and aluminium sulfide is also much softer than pure, fused alumina, making the slag easier to break up mechanically.
• The alumina/aluminium sulphide slag mix reacts readily with water through hydrolysis of the sulphide: Al
2S3 + 6 H2O ---> 2 Al(OH)3 + 3 H2S. This breaks up the slag into a (stinky) hydrated alumina slurry (or mud), giving easy access to the metal globules.

You can find an example of a 300 g S-boosted silicon thermite at this blog post of mine.

But that's the good news and there's some bad news too: the aluminium sulfide is so prone to hydrolysis, that even the newly fused slag positively reeks of H2S, in plain English: rotten eggs. Needless to say, adding water or a mineral acid to it, seriously aggravates the problem. Not only does H2S stink terribly, it's also toxic and it's perceptible even in trace amounts.

(Tip: if you're going to treat an alumina/aluminium sulfide slag mix with water, use copious amounts of bleach instead of pure water: the sodium hypochlorite in the bleach will convert much of the H2S to elemental sulfur, which is even recoverable).

In a nutshell, I got so fed up with the smell of rotten eggs, I decided to try and replace the S-booster mix with a sulfur-free system. I chose to investigate a potassium chlorate/Al mix, which reacts according to 2 Al + KClO3 ---> Al2O3 + KCl with an estimated ΔH ≈ 7.11 kJ/g (of stoichiometric mix) heat generated. I had used such mixes before for lighting thermites.

Initial tests with a silica/Al/KClO3 = 100/72/27 mix showed clearly that the reaction proceeded self-sustainingly and that Si metal was formed, in a hard, porous alumina matrix. I gradually stepped up the amount of booster mix to 100/84/57 and later to SiO2/Al/KClO3 = 100/96/81, to find that progressively more of the slag ends up at the bottom of the crucible (I used mostly 20 g mini batches for the development work) because of the increasingly high peak temperatures during the reactions.

Much of this development can be followed here and on subsequent pages at the ABYMC forum (where I post as Gert from England).

The main problem remains slag/metal separation, both in situ and after the reaction products have cooled down: the pure, fused alumina freezes up quickly into a very, very hard mass. 32 w% HCl doesn't even begin to dent it and forget about mechanical separation: this stuff is HARD!

I then proceeded to test calcium fluoride (Fluorite, CaF2, calcium fluoride) as a potential flux, at 20 w% added to the promising 100/96/81 formulation (this then became 100/96/81/55 - with 55 the CaF2) . Although it made a world of difference in the sense that much larger globules of Si metal form, the slag remains extremely hard and insensitive to HCl. Another test at 40 w% CaF2 showed that at that level the reaction was being slowed down, probably due to adding so much inert material, and hence slag metal separation deteriorated again due to lower peak temperatures.

The purpose of the CaF2 is essentially that of slag fluidiser. Fluorite is inert in these conditions and takes no part in any chemical reactions but has a much lower melting point than pure alumina: 1402 C (2555 F) for fluorite against 2054 C (3729 F) for alumina. Adding relatively small amounts of the lower melting fluorite to the thermite mix therefore helps keeping the slag as fluid as possible for as long as possible, thereby allowing the slag metal mix to collect at the bottom of the crucible and the metal and slag to separate out by gravity.

So far the best formulation has been found to be SiO2 / Al / KClO3 / CaF2 = 100 / 96 / 81 / 55 (all parts by weight), which has been tested in a 100 g thermite mix with good results, although there is room for improvement. Slag/metal separation is generally good with large blobs of pure silicon metal being formed but adhesion of the slag to the metal remains a problem. Further attempts at optimising will include increasing the portion of booster mix and flux to obtain a mix that runs even hotter and should by rights lead to even better slag/metal separation. Another possibility is to use a flux that is even lower melting, such as Cryolite (Na3AlF6, sodium hexafluoroaluminate). Expect updates!

The principle of chlorate-boosted thermite reactions has in the mean time also been successfully deployed on an even more notoriously difficult reaction, that of extracting titanium metal from titanium dioxide. And the production of ferrotitanium (60 w% iron - 40 w% titanium) without any booster has also been demonstrated separately.

A simple but effective thermodynamical model of what goes on thermally inside a thermite mix has also been developed and has been shown to be accurate in estimating the peak temperatures during reaction. More on that in a dedicated post to come soon.

Here's an example of a copper thermite reaction.

Related reading: Manganese thermite from manganese (II) oxide.

Sunday, March 23, 2008

Cold Easter Fusion

From Pharyngula (PZ Myers):

This is Easter, the day Christians everywhere set aside to celebrate the day they were hoaxed by a gang of Middle Eastern charlatans into believing a local mystic rose from the dead. Zeno finds that this year it's also a day to remember another flop: the cold fusion debacle.

It's been 19 years since Pons and Fleischmann announced their purported discovery of a mechanism for generating energy from a room-temperature fusion cell. Unlike the resurrection, I was actually there for that one. I was a post-doc at the University of Utah at that time, in the building right next door to where Pons and Fleischmann worked, and I attended the various events associated with the "discovery".

Even then, there was reason to doubt: I remember being mystified that they'd chosen to announce it via press release rather than a scientific publication (a strategy that you'll notice the Discovery Institute has expanded upon), and when I attended Pons lecture on the phenomenon, I was bothered by the lack of mechanism and the uncontrollable variability in the experiments — it was basically a laundry list of experiments done, some of which did nothing, some that got a trickle of excess energy output, and others that exploded. It was exciting and interesting, and we all hoped that this was real, but it wasn't science yet.

And it still isn't. I guess some people are still puttering away at it, but it's still an inconsistent phenomenological collection of anecdotes.

If only Pons and Fleischmann had thought to make a religion of it, that wouldn't be a problem.

Friday, March 14, 2008

Titanium metal from TiO2 thermite reaction

It's with some pride that I announce the fact that I've produced titanium metal from a homemade potassium chlorate-boosted Anatase thermite...

Titanium_metalEarlier, I had developed a sulfur-free potassium chlorate boosted formulation for SiO2 (silicon) thermites. You can find the rationale for this development on this forum here and on subsequent pages. More on the sulfur-free chlorate boosted formulation for SiO2 thermite in a separate post soon to come. [Edit: you can find the post on a sulfur-free silicon thermite here]. And here's a post on Manganese thermite from manganese (II) oxide.

A couple of weeks ago I had adjusted the best-so-far SiO2/Al/KClO3/CaF2 = 100/96/81/55 formulation to TiO2/Al/KClO3/CaF2 = 100/72/61/47 and tried it with my home brewed 'emulsion paint' TiO2 and it burned but somewhat sputteringly and of course no metal. The home made TiO2 undoubtedly contained residues of paint resin and possibly other white pigments. Without concentrated sulfuric acid, it is difficult to purify it.

But I recently bought a good grade of pure TiO2, Anatase "99 %", so I decided to stick that in there too, as well as in an adjusted formulation with magnalium (a 50/50 alloy of aluminium and magnesium - denoted MgAl) . The total charge in both cases was 20 g, contained in an egg cup and embedded in a sand-filled steel bucket. Materials used: very fine Anatase 99 %, 400 mesh Al powder, potassium chlorate reagent grade, ground Fluorite for CaF2. Ignition with a stoichiometric mix of Al/KClO3 mix and an Mg ribbon fuse. The experimental set-up is very similar to the silicon thermite described here.

The Anatase formulation burns like hell: very fast and furious, very regular: it's completely on a par with its SiO2 analog. Immediately after the reaction had finished I went over to look and saw three quite large, darker regions at the bottom of the white/yellow hot crucible (eggcup). Darker regions in the hot slag are an indication of materials with higher heat conductivity (such as metals), I've seen this happen many times before.

But at that point I didn't even dare to hope too much and decided to light the magnalium version (TiO2/MgAl/KClO3/CaF2 = 100/82/61/49). That basically exploded! I knew it was going to be fast, possibly too fast, so I ran away after lighting the Mg ribbon and the whole thing went "poof!" while I still had my back to it, throwing content as far as a meter away from the test point!

But after the straight Al test had cooled down it became clear that the darker regions were indeed titanium metal: oxidised (only slightly) on the outside on the top and lightly covered in dark slag at the bottom, a little buffing up with rough sanding paper revealed the hard, shiny metal. It has a slight golden tinge to it. I'm now the proud owner of three 4 - 6 mm blobs of home made titanium metal, total weight about 1.9 g.

Interestingly, slag/metal separation was simply exemplary: most of the metal neatly at the bottom, easily separable from the slag mix. It appears to me a lot of the slag had been blown off, covering the globules only in a slight oxide/slag coating. The metal had also passivated, like Al does.

Tonight I'll be running a larger test to confirm.

It may also prove difficult to get chemical confirmation of the metal's identity: Titanium only really dissolves in concentrated acids like sulfuric or nitric, also apparently HF. Nice one... I haven't got any of those...


Another test using the same formulation but this time with a larger batch size (92 g) also yielded good metal, including one blob of 11.5 g, the thickness of a pound coin but larger in surface. Some smaller globules were spewed out of the crucible, so it's probably running a little too hot.

While pure titanium is much more resistant to 32 w% HCl than say steel, it does dissolve slightly, given a bit of time and temperature. The resulting solution is a nice Amethyst type purple, due to aqueous Ti3+. The solution tests positive for Ti with hydrogen peroxide according to this test here. There is therefore no reasonable doubt left that the metal produced is in fact elemental titanium metal.

The reduction of titanium dioxide with Al powder has also been used twice to produce a ferrotitanium alloy (in my case approx. 60 w% Fe and 40 w% Ti) by co-reducing Fe2O3 (iron (III) oxide, Hematite) and TiO2 (here Anatase) with Al powder. The oxide mix was composed of 1 mol of TiO2 and 0.85 mol of Fe2O3. Here, no chlorate-booster is needed because the reduction of Fe2O3 to Fe metal provides the heat needed to sustain the reaction and to ensure the reaction products are obtained in molten form. CaF2 was used as a fluxing agent. Two 20 g reactions were carried out, both yielding exemplary slag/metal separation and clean 5 g reguli of the ferrotitanium alloy.

Without a shimmer of doubt this process can be applied to make other pure titanium alloys of precise composition.

And other heat booster systems besides the potassium chlorate/aluminium powder system have also been tested successfully. A booster system for thermites usually comprises of aluminium and an oxidiser. In the conditions of high temperature that exist inside an ignited thermite mixture, the oxidiser oxidises the aluminium to alumina and the formation of this oxide is accompanied by great release of heat, which is used to keep the thermite 'burning', as well as reach a sufficiently high end temperature. The latter is necessary to ensure the reaction products, the target metal and slag, are obtained in liquid form and can separate out, thereby obtaining the pure metal as a solid (after cooling).

Other well-known oxidisers for aluminium are nitrates and sulfates. For sodium nitrate the booster reaction is:

NaNO3 + 2 Al ----> Na + 1/2 N2 + Al2O3

This reaction produces about 700 kJ of reaction heat per mol of nitrate.

A typical sulfate is calcium sulfate, used extensively in plaster of Paris, wall fillers, writing chalks and other OTC products and it reacts with aluminium according to:

CaSO4 + 8/3 Al ---> CaS + 4/3 Al2O3

It releases nearly 1,300 kJ of heat per mol of sulfate.

I have used both sodium nitrate/aluminium and calcium sulfate/aluminium with success as heat boosters in titanium metal producing thermites (and I've got the metal to prove it!)

Thursday, March 13, 2008

Spitzer's answering phone messages...

And encore: Dunlap on $80,000 worth of crack whores:

Monday, March 10, 2008

Expelled: The Movie

Conservative blogger Ed Morrissey, from Captain's Quarters, reviewed a preview of Expelled, Ben Stein's latest brainchild and surprisingly didn't make a bad job of it. But there remain in his essay a number of simplifications, which I want to point out here. I need also to clarify that I haven't seen the movie.


Before discussing my feelings about the film, which is still in post-production and will not go into release until April, I should explain my approach to the ID/evolution debate. I believe evolution is demonstrably proven in enough examples to say that its effect on variation in species cannot be denied. The example I used tonight in discussing this with another viewer (certainly not the only example) is antibiotic effects on bacteria. Antibiotics that kill 99% of bacteria eventually promote the survival and the expansion of the 1% that resist them, created superbacteria that require another set of antibiotics to cure, and so on.

That said, evolution does not interfere with my faith in God. God certainly could have created the universe with a design that included life. The rational laws of nature would include evolution, as well as the myriad of other rational and mathematically provable mechanisms that undergird nature. In fact, the impulse of man to discover the rational laws of nature began with the belief in a rational God, as scientists understood nature's rationality to reveal an intelligent Creator.

I'd go deeper than that, but Dinesh D'Souza covers it nicely enough already in his book What's So Great About Christianity, and it's getting late enough as it is. Suffice it to say that evolution doesn't present a threat to my worldview.

So, we have at least one conservative blogger who doesn't have a problem with evolutionary biology. Good man...
Rationally, we have to admit that some use ID as an excuse to teach the more literal form of Creationism that has been used to argue against evolution entirely, especially against teaching evolution in primary-school classrooms. That admission does not appear in Expelled, which is a glaring omission. It tends to take out of context the frustration some scientists have about ID, and its place in polarizing the debate over its use. Properly framed, ID accepts all of the science without accepting its transformation into its own belief system.

Very magnanimous indeed, this admission of a glaring hole and the correct pointing to a lack of context provided by Stein. To ignore the genuine and justified frustration scientists feel when confronted with this pot pourri of religion, Young Earth Creationism and Intelligent Design, should not be left out of any debate on Stein's chosen subject matter.

But soon after Ed starts to go wrong:
What do I mean by that? In this, the film does an excellent job of demonstrating atheism as a belief system. Atheism as represented by Richard Dawkings and others in this film gets exposed as exactly the kind of belief system they claim to despise. They can't prove God exists -- and they can't prove God doesn't exist. They make the common fallacy of arguing that absence of evidence amounts to evidence of absence.

The old chestnut: atheism as a belief system. Absence of belief doesn't make belief (although certain brands of atheism could, on the face of things, easily be mistaken for some kind of faith). Ed, already in a hole, decided to keep digging by emphasising the word 'exactly'. As Dawkins himself pointed out (in a discussion with the philosopher A.C. Grayling, if I recall well), there is no such thing as 'positivist atheism': no one can prove or disprove the existence of G-d and in that sense we're all agnostics. Dawkins doesn't "make the common fallacy of arguing that absence of evidence amounts to evidence of absence", as Ed claims, instead he too accepts that he can't know and that at the end of the day the individual does need to go beyond the evidence to decide on theism or atheism. But in the absence of any positive evidence for the existence of a theistic G-d, believing in His existence requires a far greater leap of faith. Theism and atheism therefore do not mirror each other, at least not philosophically speaking.
But in a way, this is all secondary to the real issue of the film: academic intolerance. The debate over ID vs Darwinism sets the table for a truly disturbing look at academia. Science should be about the free debate and research of ideas and hypotheses for duplicable results and provable theorems. However, as the examples Stein and the film provide amply show, the Darwinist academic establishment will brook no dissent from the orthodoxy -- and scientists have to be shown with hidden faces to speak to the issue for the film.

Here Ed merely parrots the undoubtedly exaggerated message of the movie but clearly the thesis of suppression of dissent is a fallacy: ID proponents are vocal and can be heard loudly and clearly. T'inkerwebs are full of opinion on it, as well as commentary, columns, now a movie and more besides that, but it's short on actual empirical research to back up any claims.
Amusingly, Stein asks people how the first cell came to be. None of the scientists could give him a straight answer. Dawkins himself admits he doesn't know and that no one else does, either -- but postulates that aliens could have brought life to this planet, and then postulates that another alien civilization could have brought life to that planet, and so on. He then concedes that one entity could have been the original source ... but insists that entity could not possibly have been God. For this he gives absolutely no evidence at all, relegating it as a belief system somewhat akin to Scientology.

Amusingly (sigh). Here Ed shows a truly bewildering and rather puerile ignorance of how scientific processes work. It's the one thing creationists will always bring up: the theory [EB] can't explain everything (yet) ergo the rest must be incorrect. Funny how they never apply the same logic to other scientific paradigms, many of which (quantum physics, to name but one) are also incomplete and still in flux.

[snip] Less effective is the heavy references to the Nazis in the movie. Although emotionally affecting for some obvious reasons, the fact is that while the Nazis were mostly Darwinists (along with a lot of other things), the vast majority of Darwinists aren't Nazis. Certainly the eugenicists in Nazi Germany were mightily influenced by Darwinism, but America had its own eugenicists, which the film points out.

Thanks, Ed, but there's a lot more to the pernicious attempt at linking Darwin to Hitler than your rather half-hearted 'most Darwinists aren't Nazis' spiel.

This here article by Michael Ruse, Professor of Philosophy at FSU debunks the Hitler - Darwin connection in some detail and I'll only quote a short excerpt (I warmly recommend reading the whole article):

[...] whatever the initial approval, the Nazi ideologists quickly realized how completely antithetical the whole evolution idea was to their own ideology. Not only are we first cousins to the monkeys but, even worse, the Aryans are brothers and sisters with the Jews, the Slavs, the gypsies, and the rest of the world's riffraff and degenerates. The greatest German evolutionist of the 19th century was Ernst Haeckel — a man whose solution to the Jewish problem was to interbreed with them so they would no longer exist as a definite group. There was not much celebration of this man and his ideas in the upper levels of the Nazi hierarchy.

So, as always, be careful not to be seduced by the ideas and claims of the anti-evolutionists. They are not scientists and, to be perfectly honest, they are not very good historians either.

But there's much more too. For one, ideas about eugenics ('race hygiene') predate Darwin and WW II by centuries, if not thousands of years. Aristotle wrote about the superiority of the 'Greek race' and provided justifications for the enslavement of conquered people as 'inferiors'.

Most cultures and their nationalistic narratives contain an element of cultural supremacy, Nazi Germany wasn't unique in that respect.

Eugenics, through the pseudo-scientific work of Francis Galton, a cousin of Charles Darwin, did receive a boost from Darwin's theory, by means of hasty and self-serving interpretations of the then embryonic science now known as evolutionary biology. Racist ideas at the time were absolutely rife in Britain and it must come as no surprise that these ideas quickly made inroads into the British intelligentsia. Notably H.G. Wells was a great fan of this renewed pseudo-science of eugenics.

Christians have in the past endorsed their own eugenistic ideas, because after all 'G-d is white' and people of colour were believed to be the offspring of G-d's white children and primates. This provided a Christian justification for slavery. More recently, Eugène Terre'Blanche's South African Afrikaner Weerstands Beweging was literally littered with Christians whose claim on the land was based on the idea that 'G-d is white' and the earth belongs to white people.

One cannot help but wonder whether Stein's repeated references to the Nazis are borne out of ignorance or out of sensationalism, but I suspect the latter...
I should point out that the film has not finished production, and that changes will be made between now and its release in April. The filmmakers just completed an interview with Christopher Hitchens and will include it in the final cut. I believe other changes may be made which could address some of the criticisms I've written here.

Overall, though, the film presents a powerful argument not for intelligent design as much as for the freedom of scientific inquiry. If scientists get punished for challenging orthodoxy, we will not expand our learning but ossify it in concrete. Expelled: The Movie is entertaining, maddening, funny, and provocative. Keep an eye out for it in theaters in two months.

While the idea that ruling orthodoxies should always be challengeable is very much part of the scientific method, it's foolish to believe that all challengers are equal. Would we find it acceptable to provide tenure for a physics professor who wants to challenge the widely accepted orthodoxy that the earth is round and spherical, from a Flat Earth Society perspective? How about a historian wanting to challenge the proved and accepted wisdom of the Holocaust?

It may seem a long shot to link Flat Earth nuts, Holocaust denying "professors" and proponents of Intelligent Design and yet the analogy can be made easily. All three start from rigid assumptions about the world ('the Earth is flat, not round', 'the Holocaust is a Jewish lie' and 'G-d the Creator exists and had a dab hand in the origin and evolution of life on Earth') and then set out to seek evidence to prove that hypothesis. That's unscientific and can only lead to bias and forcing the hand of evidence.

I haven't seen the movie and therefore cannot judge Stein's case for claiming some academics were ostracised or denied tenure for their ideas on Intelligent Design. But I'm willing to believe it: academic freedom doesn't mean all opinions are equal and should be pursued with equal rigour: the Earth isn't flat, the Holocaust did happen and G-d's existence and his DNA handiwork cannot be proved or disproved by means of science. To believe otherwise is naive and unscientific to boot.

Sunday, March 09, 2008

Endgame in Megiddo?

Sam Kiley - The Observer

Faced with a doomsday scenario, Israel must sit down with Hamas

Quick to celebrate, and quick to erect the green flags of its movement outside the home of the Palestinian who murdered eight Jews in Jerusalem last week, Hamas is setting the agenda for politics in the region and a trap for Israel.

It is a doomsday scenario and goes like this: Hamas claims responsibility for the Jerusalem murders (which it apparently did on Friday), continues to rain rockets into the Israeli towns of Ashkelon and Sderot, Israel's government orders a massive invasion of Hamas-controlled Gaza to 'topple' Hamas. So far, so local.

But while Israel is flattening Gaza and carrying out Deputy Defence Minister Matan Vilna'i's threat of a shoah or (near) holocaust, Hizbollah launches a massive attack on Israel in the north with modern rockets supplied through Syria by Iran. The US navy, which recently moved three battleships close to Lebanon's shores, is ordered to help defend Israel and fires cruise missiles into Hizbollah and Syrian army positions. Iran retaliates. The rest is ashes.

A bit far-fetched? A narrative for one of Tim LaHaye's 'end time' Armageddon prophecy novels, which sell in their millions to America's Christian fundamentalist audience? Maybe.

Since Israel's disastrous invasion of Lebanon in 2006 in response to rocket attacks and the kidnapping of two Israeli soldiers by its fighters, Hizbollah has been itching for a rematch. When Imad Fayez Mugniyeh, Hizbollah's military chief and author of dozens of terrorist attacks, was assassinated last month, the Islamic movement promised bloody revenge.

Hizbollah has no doubt been flooded with military hardware from Iran, where Mahmoud Ahmadinejad has made no secret of his desire to destroy Israel. He also shares some of the fantasies of extremist Christians that the end is nigh, that this is desirable, and that a messiah (or mahdi) will rise out of the ashes of a final battle between good and evil at Armageddon (a real place, now called Megiddo, in northern Israel).

Even if Hamas and Hizbollah's ambitions remain more mundane, trapping Israel into a massive attack on Gaza remains a significant threat to the Jewish state, not least because in a US election year another Middle Eastern conflagration will strengthen growing American fears that Israel is not a strategic asset in the region but a liability.

Hamas remains popular on the West Bank, and dominant in Gaza, as much for what it stands for as for what it is not. It is not the Palestinian Authority or Fatah, the movement founded by Yasser Arafat, which has been in on-off talks with Israel since 1993. The negotiations, from a Palestinian perspective, have yielded nothing, but have produced a class of sharp-suited professional talkers, President Mahmoud Abbas, Prime Minister Ahmed Qurei, and chief negotiator Saeb Erekat among them.

Hamas, meanwhile, has been 'martyred'. Aid from the EU and the US intended to keep the administration of the Palestinian territories alive was cut the moment Hamas was elected in 2006, and is now only channelled to the West Bank, which is under PA/Fatah control.

Since Hamas took over from the PA/ Fatah in a civil war in Gaza last year, the enclave of 1.5 million people has been under a strangulating siege imposed by Israel in response to the Islamic movement's almost daily rocket attacks. Gazans feel collectively punished for the actions of Hamas and are often more likely to support the organisation.

Ahmed Yusef, senior adviser to the Hamas leader Ismail Haniyeh, (who is in hiding from Israeli attack) said Hamas wanted negotiations with Israel. Although it is committed to the destruction of the 'Zionist entity', he said 'we could put that to one side for five or 10 years and see how peace worked out'.

This is hardly an olive branch. Hamas has been labelled a terrorist organisation by the US, the UK, and most of Israel's backers. Yusef said: 'So what? Negotiations are between enemies, not friends.'

But Hamas's desire for negotiations does offer Israel a way out of Hamas's doomsday trap, and, according to a recent poll in Israel's leading daily newspaper Ha'aretz, 64 per cent of Israelis agree. They said what was until recently unthinkable - that Israel should talk to Hamas.

If Israel defied Washington and talked to Hamas, Palestinian support for its rocket attacks, which in any case cause much more suffering to Gazans than Israelis, would naturally wane and that could lead to the ceasefire the whole region so desperately needs.