Talk:Synthesis of precious metals

message: For gold, also one can start from 201Hg in theory. Check masses at http://conjeturas.blogia.com/2006/061601-mercurio.php   Arivero 16:24, 28 June 2006 (UTC)
replies: text: Iridium and platinum would likely replace it in that role. Of all the precious metals, Ir is the only one that cannot be recovered from spent nuclear fuel, nor can it be made from cheaper elements by neutron reactions (you could synthesize it from Os or Pt, both of which are as expensive, if not more so, than Ir). Pt can be synthesized, but the starting material must be Ir. So the price of Pt will drop until it is slightly higher than that of Ir (which is currently much cheaper than platinum). Thus, if the methods described in this article become widely used, the prices of all precious metals except iridium and platinum will likely plummet to "non-precious" levels, and platinum's price will drop until it stabilizes at slightly higher than that of Iridium, leaving iridium and platinum as the only two precious metals. Imagine Glenn Beck promoting Iridiumline on his show! ;-) Stonemason89 (talk) 18:36, 30 July 2010 (UTC)
thread_title: Gold from mercury

message: The two articles are similar. One just shows some specifics which would be a good addition to the other article.--71.102.144.27 04:43, 9 February 2007 (UTC)
replies: text: I'm deleting the mergeto tag because that's a disambiguation page now. — Randall Bart (talk) 18:22, 3 August 2007 (UTC)
thread_title: Transmutation

message: This article states that 1 kg of palladium is produced for every ton (imperial), could they mean every tonne (metric).  —Preceding unsigned comment added by 24.65.87.238 (talk) 02:58, 2 January 2008 (UTC)
replies: text: Probably not, the metric ton doesn't convert well into pounds and besides, is totally redundant in the first place, being equal to exactly one megagram. Sounds like something some wankers dreamed up just so they could keep saying "This weighs a ton!" after having converted to metric.Zaphraud (talk) 08:17, 2 January 2011 (UTC)
thread_title: Units

message: The caption for this nice picture says "Synthetic made gold crystals", but which of the processes mentioned in this article was used? --Palnatoke (talk) 07:06, 28 January 2010 (UTC)
replies: text: Please read: Chemical transport reaction Au powder in chlorine gas at ~300°C --Alchemist-hp (talk) 10:43, 19 February 2010 (UTC)
thread_title:  How was this made? 

message: Would a high precision concentrated solar (sun rays)  system reaching thousands of degrees Celsius do anything in this context? 
Has anybody researched the small scale atomic reactions in these systems where materials are reduced to helium and hydrogen (as in high energy plasma systems)? פשוט pashute ♫ (talk) 02:05, 3 July 2011 (UTC)
thread_title:  Concentrated solar synthesis 

message: The 'Gold synthesis from mercury' section starts with: "Gold obtained by mining has copper and silver impurities".  What has that paragraph got to do with the synthesis from ?  Astronaut (talk) 16:31, 25 February 2012 (UTC)
replies: text: Removed that irrelevancy as well as the redundant section - covered in nuclear reactor section below. Vsmith (talk) 16:48, 25 February 2012 (UTC)
thread_title:  Gold synthesis from mercury confusion 

message: Now I'm no fancy big-city scientist, but it seems to me that "neutron capture" has nothing to do with elemental transmutation. Protons are the particles that determine what element the atom is, not neutrons. Go easy on me, I know very little of nuclear physics.  — Preceding unsigned comment added by 96.48.41.161 (talk) 07:50, 3 June 2012 (UTC)
replies: text: When too many neutrons are captured, some of them beta decay into protons, which causes elemental transmutation. Double sharp (talk) 07:22, 18 June 2012 (UTC)
thread_title:  I do not understand. 

message: The rhodium, ruthenium, and palladium sections consider rather short-lived radioisotopes rather than stable isotopes created by nuclear fission. Because for most practical purposes radioactivity is unacceptable, why does the article mainly describe short-lived, and rather useless, radioisotopes, rather than stable isotopes created? In fact, the rhodium section should remark that 103Ru decays to rhodium's only stable isotope.--Jasper Deng (talk) 00:03, 25 November 2012 (UTC)
replies: text: That's a good question, and I don't know the answer. However, I did add that 103Ru decays to 103Rh. Double sharp (talk) 05:34, 25 November 2012 (UTC)
replies: text: OK, I think I see what is going on. The article is being structured by what element is created first as a fission product, and not what it decays into. For example, in the Rh section, 102Rh is mentioned, which decays to stable 102Ru (80%) and 102Pd (20%). 107Pd decays to stable 107Ag. 106Ru decays to 106Rh, which decays to stable 106Pd. However, I think the section would be more useful if organized by the end product (after decay), rather than what the fission products are originally. Double sharp (talk) 05:39, 25 November 2012 (UTC)
replies: text: Exactly. The main reason is that users come here for a usable end product.--Jasper Deng (talk) 05:46, 25 November 2012 (UTC)
replies: text: The only instance where the radioactivity may be acceptable is 107Pd, with its very low decay energy and long half-life. Double sharp (talk) 06:55, 3 November 2013 (UTC)
thread_title:  Why do we consider radioisotope synthesis? 

message: "Gold was synthesized from mercury by neutron bombardment in 1941, but the isotopes of gold produced were all radioactive.[3] In 1924, a Japanese physicist, Hantaro Nagaoka, accomplished the same feat."
Is the second statement accurate?  — Preceding unsigned comment added by TMBTC (talk • contribs) 19:28, 25 May 2013 (UTC)
thread_title:  Accuracy? 

message: There are serious errors in this article. Even just assuming what is written is true, it doesn't add up.
Starting in Ruthenium section.  The article appears to have egregiously misunderstood reference #1.  The amounts produced per ton or tonne can be far different (certainly far less) than claimed.   The claims don't even add up for a simple single error.
 
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"...  Each kilogram of the fission products of 235U will contain 63.44 grams of ruthenium isotopes with halflives longer than a day. Since a typical used nuclear fuel contains about 3% fission products, one ton of used fuel will contain about 1.9 kg of ruthenium. ..."   
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The first sentence is incorrect.  Fission daughters of u235 are less than 1% Ruthenium, not 6%. Here is a graph...https://www.google.com/search?q=decay+products+percentage&client=tablet-android-att-us&source=android-browser&prmd=inv&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiGsrvGiPrTAhXBzFQKHQ6FAyIQ_AUICSgB&biw=1024&bih=768#tbm=isch&q=fissionn+daughter+percentage+u235&imgrc=qaJogQbo2kwchM:
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One tonne of used fuel (a ton would be different) having 3% fission products  that came from u235 would yield 30 kilograms of fission products. Less than 1% or 300 grams would be ruthenium...before decay.
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There are several problems though.  Burn up is measured per tonne of fissionable elements.  Fuel is not just these elements. Most fuels are not metallic, but oxides or carbides (somethimes).  Additionally there is cladding and burn able poisons.  The percentage of fissionable elements in the fuel assemblies is much lower that the total mass of the fuel assemblies.
Beyond that the fission products are not just from u235, but from other actinides created at power.
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There are fundamental problems with this article and it should be taken down until it can be majorly revised.
BGriffin (talk) 19:11, 18 May 2017 (UTC)
thread_title:  This article should be taken down or severely cut back to just what is known fact. 

message: Many articles, including this one, make the dubious assertion that after 10 half-lives any arbitrary quantity of radioactive material will have decayed to the point of being essentially non-radioactive (or at least no more so than natural background radiation), without qualification regarding the amount of radioactivity present to begin with.  After 10 half-lives, the quantity of radioisotope present will have decreased by a factor of 2-10 = 1/1024 = about 0.001 (0.0009765625 exactly).  Some versions of this claim use wording like "substantially all" or "essentially all" of the radioisotope will have decayed, which suggests there is a fallacy of absolute vs. relative magnitude going on here; while a loss of 99.9% (or 99.90234375%) could certainly be described as "nearly all" of a quantity of a substance relative to the original amount, what really matters here is the absolute quantity of radioactivity remaining after a given period of time, not how it compares to the original amount.  If you start with 1 TBq/kg of radioactivity, then after 10 half-lives you will have about 1 GBq/kg, a thousand times less than you started with - but still very hot!  If you give it another 20 half-lives (total of 30 so far), then you get a little less than 1 kBq/kg, which is more reasonable though still a bit high.  Another 3 half-lives (total of 33) would bring it down to around 125 Bq/kg.
The ruthenium example started with 109 TBq/kg, so it would need about 40 half lives to get down to 109 Bq/kg.  For comparison, the typical banana, frequently used as an example of a commonly-encountered measurably but harmlessly radioactive object, registers around 130 Bq/kg.  A paper by NIH discussing radioactivity in tiles (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5771965/) mentions a recommended upper limit of 370 Bq/kg "Radium equivalent activity", a measure generally used in relation to external gamma radiation exposure hazard (e.g. from building materials).    This is not necessarily a strict upper limit for what is safe, and the absolute quantity of substance present (X Bq/kg * how many kg?) is also relevant; moderately higher levels might be acceptable for end uses involving gram-size or smaller quantities, or highly diluted forms (e.g. as a 0.1% alloying component).  In any case, 109 GBq/kg (or 109 MBq/g) is still far too hot for any reasonable use, other than purposely as a radiation source.
71.255.247.70 (talk) 14:04, 11 April 2020 (UTC)
thread_title:  10 Half-lives myth 

message: The main reason is almost certainly: economics. And it is quite possible that those who have done research into it are not particularly willing to tell the world, where the economic hurdles lie in detail. But could we still cover that a bit more? Thus far, it is only mentioned that Seaborg's gold production method was uneconomical by several orders of magnitude, but other pathways seem both simpler and to have better ratios of value of input / value of output... Hobbitschuster (talk) 16:29, 2 January 2022 (UTC)
replies: text: Having spent way too much time trying to find out more, one of the main problems seems to be "the price of neutrons". If we assume that spallation neutrons "cost" ~30 MeV per neutron (and we can't do much better than that currently) then none of the proposed reactions have enough of a mass defect to recoup the 30 MeV (most seem to range at ~10 MeV per neutron, some of which is lost via neutrinos, fission of course is at 200 MeV and itself produces neutrons, those numbers are the reason why the energy amplifier is a workable concept). And at current energy prices 30 MeV per neutron isn't worth it. Not remotely. The story of course changes if instead of specifically produced neutrons we use what could be called "waste neutrons". If for example a surface exposed to otherwise unwanted neutron radiation were clad in a suitable transmutation target, the economics would change. The most extreme proposal would be control rods made out of a transmutation targets inside a nuclear power plant. However, given that the neutron absorption cross section would decrease by orders of magnitude compared to current materials (often Hafnium which has too many stable isotopes to transmute much over a reactor lifetime), the whole design of nuclear power plants would have to be changed and that doesn't seem likely. Furthermore the "everything that comes from the 'hot' zone of a nuclear facility must be treated as hot no matter what" rule would have to be changed for transmutation products if any "non-hot" use is intended... Hobbitschuster (talk) 21:07, 5 February 2022 (UTC)
thread_title:  Why isn't any of this done? 

message: If Seaborg was able to achieve what may be the closest to-date equivalent of the Philosopher's Stone using nuclear fission, is it possible to achieve the same result using nuclear fusion by fusing the atoms of lighter elements into heavier ones such as gold, silver and the rare-earth metals?  — Preceding unsigned comment added by 2001:48F8:8:1C9D:50D3:6322:1BBB:D543 (talk) 18:28, 5 February 2022 (UTC)
replies: text: generally speaking the energy requirements for endothermic nuclear reactions aren't "worth it" at scale unless you are talking about very exotic, very expensive nuclei. Just multiply a few Megaelectronvolt with Avogadro's number on wolfram alpha to see what I mean. And all nuclei heavier than nickel/iron have binding energy in such ranges that fission is a more promising mode of releasing energy than fusion. The reverse is true for nuclei lighter than iron/nickel. Now what is possibly promising (in "first principles" theory at least) for the creation of gold from cheap original materials is this:  hit by a 10 MeV gamma ray has a non negligible chance of "shedding" a neutron.  is unstable and will relatively quickly decay to...  which is the only stable isotope of gold. Now there are a couple of problems with this...  itself has a non-negligible gamma ray cross section and if it "sheds" a neutron, it'll be converted to unstable  which will decay to stable . Another is that the cross section of all involved nuclei for neutron absorption is much higher than for interaction with gamma rays - and you're constantly producing neutrons from all your nuclear reactions to turn mercury into Gold or gold into platinum... and finally... Ten MeV gammas do not come for free... Hobbitschuster (talk) 20:55, 5 February 2022 (UTC)
thread_title:  Achievable via nuclear fusion? 

message: The link in the reference "Kolarik, Zdenek; Renard, Edouard V. (2003). "Recovery of Value Fission Platinoids from Spent Nuclear Fuel. Part II: Separation Process" (PDF). Platinum Metals Review. 47 (2): 123–131" actually points to part I.
None of the Kolarik et al references open automatically when clicked upon, but this maight be e.g. a firewall issue.150.227.15.253 (talk) 21:32, 7 February 2022 (UTC)
thread_title:  Reference error