View source for Synthesis of precious metals

{{Short description|Production of rare lustrous high-conductivity elements}}
The '''synthesis of [[precious metals]]''' involves the use of either [[nuclear reactor]]s or [[particle accelerator]]s to produce these elements.

==Precious metals occurring as fission products==

[[Ruthenium]] and [[rhodium]] are precious metals produced as a small percentage of the fission products from the [[nuclear fission]] of [[uranium]]. The longest [[half-life|half-live]]s of the [[radioisotope]]s of these elements generated by nuclear fission are 373.59 days for ruthenium and 45 days for rhodium{{clarify|does not match what is said later for each element|date=July 2020}}. This makes the extraction of the non-radioactive isotope from spent nuclear fuel possible after a few years of storage, although the extract must be checked for radioactivity from trace quantities of other elements before use.<ref name="Bush">{{cite journal  | title =  Recovery of Platinum Group Metals from High Level Radioactive Waste | first = R. P. | last = Bush  |  journal = Platinum Metals Review | volume = 35 | issue = 4 | year = 1991 | pages = 202–208 | doi = 10.1595/003214091X354202208 | url = http://www.platinummetalsreview.com/pdf/pmr-v35-i4-202-208.pdf |archive-url=https://web.archive.org/web/20070927144045/www.platinummetalsreview.com/pdf/pmr-v35-i4-202-208.pdf |archive-date=2007-09-27 |url-status=dead}}</ref>

[[Image:Activity of pt group metals from uranium fission.png|thumb|450px|right|The radioactivity in MBq per gram of each of the platinum group metals which are formed by the fission of uranium.  Of the metals shown, ruthenium is the most radioactive.  Palladium has an almost constant activity, due to the very long half-life of the synthesized <sup>107</sup>Pd, while rhodium is the least radioactive.]]

=== Ruthenium ===
{{See also|Airborne radioactivity increase in Europe in autumn 2017}}
Each kilogram of the fission products of <sup>235</sup>U will contain 63.44&nbsp;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&nbsp;kg of ruthenium. The <sup>103</sup>Ru and <sup>106</sup>Ru will render the fission ruthenium very radioactive.  If the fission occurs in an instant then the ruthenium thus formed will have an activity due to <sup>103</sup>Ru of {{nowrap|109 [[Becquerel (unit)|TBq]] g<sup>−1</sup>}} and <sup>106</sup>Ru of {{nowrap|1.52 TBq g<sup>−1</sup>}}. <sup>103</sup>Ru has a half-life of about 39 days meaning that within 390 days it will have effectively decayed to the only stable isotope of rhodium, <sup>103</sup>Rh, well before any reprocessing is likely to occur. <sup>106</sup>Ru has a half-life of about 373 days, meaning that if the fuel is left to cool for 5 years before reprocessing only about 3% of the original quantity will remain; the rest will have decayed.<ref name="Bush"/> For comparison, the activity in natural [[potassium]] (due to naturally occurring {{chem|40|K|link=potassium-40}}) is about 30&nbsp;Bq per gram.<ref name=Samat>{{cite journal |last1=Bin Samat |first1=S. |last2=Green |first2=S. |last3=Beddoe |first3=A. H. |year=1997 |title=The <sup>40</sup>K activity of one gram of potassium |journal=[[Physics in Medicine and Biology]] |volume=42 |issue=2 |pages=407–413 |bibcode=1997PMB....42..407S |doi=10.1088/0031-9155/42/2/012 |pmid=9044422 |s2cid=250778838}}</ref>

=== Rhodium ===

It is possible to extract rhodium from [[used nuclear fuel]]: 1&nbsp;kg of [[fission products]] of <sup>235</sup>U contains 13.3&nbsp;grams of <sup>103</sup>Rh.  At 3% fission products by weight, one ton of used fuel will contain about 400&nbsp;grams of rhodium. The longest lived radioisotope of rhodium is <sup>102m</sup>Rh with a half-life of 2.9 years, while the ground state (<sup>102</sup>Rh) has a half-life of 207 days.<ref name="Bush"/>

Each kilogram of fission rhodium will contain 6.62&nbsp;ng of <sup>102</sup>Rh and 3.68&nbsp;ng of <sup>102m</sup>Rh. As <sup>102</sup>Rh decays by [[beta decay]] to either <sup>102</sup>Ru (80%) (some [[positron emission]] will occur) or <sup>102</sup>Pd (20%) (some [[gamma ray]] photons with about 500 keV are generated) and the excited state decays by beta decay (electron capture) to <sup>102</sup>Ru (some [[gamma ray]] photons with about 1 MeV are generated). If the fission occurs in an instant then 13.3&nbsp;grams of rhodium will contain 67.1 MBq (1.81 mCi) of <sup>102</sup>Rh and 10.8 MBq (291 μCi) of <sup>102m</sup>Rh. As it is normal to allow used nuclear fuel to stand for about five years before reprocessing, much of this activity will decay away leaving 4.7 MBq of <sup>102</sup>Rh and 5.0 MBq of <sup>102m</sup>Rh. If the rhodium metal was then left for 20 years after fission, the 13.3&nbsp;grams of rhodium metal would contain 1.3 kBq of <sup>102</sup>Rh and 500 kBq of <sup>102m</sup>Rh. Rhodium has the highest price of these precious metals ($440,000/kg in 2022<ref>{{Cite web |title=Rhodium Spot Prices Per Ounce Today, Live Bullion Price Chart USD |url=https://www.moneymetals.com/precious-metals-charts/rhodium-price |access-date=2022-06-23 |website=Money Metals Exchange |language=en}}</ref>), but the cost of the separation of the rhodium from the other metals needs to be considered{{Editorializing|date=May 2023}}, although recent high prices may create opportunity for consideration.<ref name="Bush"/>

==Precious metals produced via irradiation==

===Gold===
[[Chrysopoeia]], the artificial production of [[gold]], is the traditional goal of [[alchemy]]. Such transmutation is possible in particle accelerators or nuclear reactors, although the production cost is estimated to be a trillion times the market price of gold. Since there is only one stable gold isotope, <sup>197</sup>Au, nuclear reactions must create this isotope in order to produce usable gold.<ref name=Au-SI>{{cite web |url=https://www.scientificamerican.com/article/fact-or-fiction-lead-can-be-turned-into-gold/ |title=Fact or Fiction?: Lead Can Be Turned Into Gold |work=Scientific American |date=January 31, 2014 |first=John |last=Matson |access-date=June 21, 2024}}</ref>

Gold was synthesized from [[Mercury (element)|mercury]] by neutron bombardment in 1941, but the [[isotopes of gold]] produced were all [[radioactive]].<ref>{{cite journal |author1=R. Sherr |author2=K. T. Bainbridge |author3=H. H. Anderson  |name-list-style=amp | title=Transmutation of Mercury by Fast Neutrons | year=1941 | journal = [[Physical Review]]| volume = 60| issue = 7| pages=473–479| doi =10.1103/PhysRev.60.473  |bibcode = 1941PhRv...60..473S }}</ref> In 1924, a German scientist, [[Adolf Miethe]], reported achieving the same feat, but after various replication attempts around the world, it was deemed an experimental error.<ref>A.Miethe, "Der Zerfall des Quecksilberatoms", Naturwissenschaften, 12(1924): 597-598</ref><ref>{{cite news |url=https://www.nytimes.com/1925/10/20/archives/gold-from-mercury-impossible-new-york-university-tests-show-that.html|newspaper=[[The New York Times]] |title=
GOLD FROM MERCURY IMPOSSIBLE; New York University Tests Show That Transmutation Method Does Not Work. MIETHE PROCESS USED His Discovery of Gold Traces Laid to Use of Spanish Mercury, Which Contains Gold. |date=October 20, 1925 |access-date=September 9, 2023}}</ref><ref>{{cite web |last=Nelson |first=Robert A. |url=http://www.rexresearch.com/adept/aa7hgau.htm |title=Adept Alchemy. Part II. Chapter 7. Transmutations of Mercury |access-date=September 9, 2023}}</ref>

In 1980, [[Glenn_T._Seaborg|Glenn Seaborg]], K. Aleklett, and the [[Bevatron]] team transmuted several thousand atoms of [[bismuth]] into gold at the [[Lawrence Berkeley National Laboratory]]. His experimental technique using [[carbon-12]] and [[Isotopes of neon|neon-20]] nuclei was able to remove protons and neutrons from the bismuth atoms. [[Glenn T. Seaborg#Return to California|Seaborg's technique]] was far too expensive to enable the routine manufacture of gold but his work was then the closest yet to emulating an aspect of the mythical [[Philosopher's stone]].<ref>
{{Cite journal
 |last1=Aleklett |first1=K.
 |last2=Morrissey |first2=D.
 |last3=Loveland |first3=W.
 |last4=McGaughey |first4=P.
 |last5=Seaborg |first5=G.
 |year=1981
 |title=Energy dependence of <sup>209</sup>Bi fragmentation in relativistic nuclear collisions
 |journal=[[Physical Review C]]
 |volume=23 |issue=3 |page=1044
 |bibcode=1981PhRvC..23.1044A
 |doi=10.1103/PhysRevC.23.1044
}}</ref><ref>{{cite news |url=https://www.telegraph.co.uk/education/4791069/The-Philosophers-Stone.html |newspaper=[[The Daily Telegraph]] |first=Robert |last=Matthews |title=The Philosopher's Stone |date=December 2, 2001 |access-date=September 22, 2020 }}</ref>

In 2002 and 2004, [[CERN]] scientists at the [[Super Proton Synchrotron]] reported producing a minuscule amount of gold nuclei from induced photon emissions within deliberate near-miss collisions of lead nuclei.<ref name="Cecchini et al 2002">{{cite journal | last=Cecchini | first=S. | last2=Giacomelli | first2=G. | last3=Giorgini | first3=M. | last4=Mandrioli | first4=G. | last5=Patrizii | first5=L. | last6=Popa | first6=V. | last7=Serra | first7=P. | last8=Sirri | first8=G. | last9=Spurio | first9=M. | title=Fragmentation cross sections of 158AGeV Pb ions in various targets measured with CR39 nuclear track detectors | journal=Nuclear Physics A | volume=707 | issue=3-4 | date=2002 | doi=10.1016/S0375-9474(02)00962-4 | doi-access=free | pages=513–524 | url=https://arxiv.org/pdf/hep-ex/0201039 | access-date=May 13, 2025| arxiv=hep-ex/0201039 }}</ref><ref name="Scheidenberger et al 2004">{{cite journal | last=Scheidenberger | first=C. | last2=Pshenichnov | first2=I. A. | last3=Sümmerer | first3=K. | last4=Ventura | first4=A. | last5=Bondorf | first5=J. P. | last6=Botvina | first6=A. S. | last7=Mishustin | first7=I. N. | last8=Boutin | first8=D. | last9=Datz | first9=S. | last10=Geissel | first10=H. | last11=Grafström | first11=P. | last12=Knudsen | first12=H. | last13=Krause | first13=H. F. | last14=Lommel | first14=B. | last15=Møller | first15=S. P. | last16=Münzenberg | first16=G. | last17=Schuch | first17=R. H. | last18=Uggerhøj | first18=E. | last19=Uggerhøj | first19=U. | last20=Vane | first20=C. R. | last21=Vilakazi | first21=Z. Z. | last22=Weick | first22=H. | title=Charge-changing interactions of ultrarelativistic Pb nuclei | journal=Physical Review C | volume=70 | issue=1 | date=July 29, 2004 | issn=0556-2813 | doi=10.1103/PhysRevC.70.014902 | doi-access=free | url=http://cds.cern.ch/record/971196/files/PhysRevC.70.014902.pdf | access-date=May 13, 2025 }}</ref> In 2022, CERN's [[ISOLDE]] team reported producing 18 gold nuclei from proton bombardment of a uranium target.<ref name="Barzakh et al 2022">{{cite journal | last=Barzakh | first=A.E. | last2=Andreyev | first2=A.N. | last3=Atanasov | first3=D. | last4=43 other members | first4=Isolde collaboration | title=Producing gold at ISOLDE-CERN | journal=Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms | volume=513 | date=2022 | doi=10.1016/j.nimb.2021.12.011 | doi-access=free | pages=26–32 | url=https://hal.science/hal-03536891/document | access-date=May 13, 2025}}</ref> In 2025, CERN's [[ALICE experiment]] team announced that over the previous decade, they had used the [[Large Hadron Collider]] to replicate the 2002 SPS mechanisms at higher energies. A total of roughly 260 billion gold nuclei were created over three experiment runs, a miniscule amount massing about 90 picograms.<ref name="CERN press release 2025">{{cite web | title=ALICE detects the conversion of lead into gold at the LHC | website=CERN | date=May 8, 2025 | url=https://home.cern/news/news/physics/alice-detects-conversion-lead-gold-lhc | access-date=May 13, 2025}}</ref><ref name="CERN 2025">{{cite journal | last1=Acharya | first1=S. | last2=Agarwal | first2=A. | last3=Aglieri Rinella | first3=G. |first4=ALICE Collaboration|last4=One thousand sixty-four other members | title=Proton emission in ultraperipheral Pb-Pb collisions at √(sNN) = 5.02 TeV | journal=Physical Review C | volume=111 | issue=5 | date=May 7, 2025 | issn=2469-9985 | doi=10.1103/PhysRevC.111.054906 | doi-access=free | arxiv=2411.07058 }}</ref>

==See also==
*[[Nuclear transmutation]]

==References==
{{reflist}}

==External links==
*[https://web.archive.org/web/20060419010807/http://www.sns.gov/ Spallation Neutron Source]
*[http://www.nndc.bnl.gov/nudat2/reCenter.jsp?z=80&n=117 Mercury 197]
*[http://www.nndc.bnl.gov/nudat2/decaysearchdirect.jsp?nuc=197HG Mercury 197 decays to Gold 197]
*{{cite journal | title = Recovery of Value Fission Platinoids from Spent Nuclear Fuel. Part I PART I: General Considerations and Basic Chemistry | url =http://www.platinummetalsreview.com/pdf/pmr-v47-i2-074-087.pdf| first1 =Zdenek | last1 =Kolarik | first2 =Edouard V. | last2 =Renard| journal = Platinum Metals Review | volume = 47 | issue = 2 | year =  2003 | pages = 74–87 | doi =10.1595/003214003X4727487|archive-url=https://web.archive.org/web/20110609174756/www.platinummetalsreview.com/pdf/pmr-v47-i2-074-087.pdf |archive-date=2011-06-09 |url-status=dead}}
*{{cite journal | title = Recovery of Value Fission Platinoids from Spent Nuclear Fuel. Part II: Separation Process| url =http://www.platinummetalsreview.com/pdf/pmr-v47-i3-123-131.pdf | first1 =Zdenek | last1 =Kolarik | first2 =Edouard V. | last2 =Renard| journal = Platinum Metals Review | volume = 47 | issue = 2 | year =  2003 | pages = 123–131 | doi =10.1595/003214003X473123131 |archive-url=https://web.archive.org/web/20110609213648/http://www.platinummetalsreview.com/pdf/pmr-v47-i3-123-131.pdf |archive-date=2011-06-09 |url-status=dead}}
*{{cite journal | doi =  10.1595/147106705X35263 | title = Potential Applications of Fission Platinoids in Industry| year =  2005 | last1 =  Kolarik | first1 =  Zdenek | last2 =  Renard | first2 =  Edouard V. | journal =  Platinum Metals Review | volume =  49 | pages =  79 | issue =  2| doi-access =  free }}

[[Category:Nuclear physics]]
[[Category:Precious metals]]

[[de:Edelmetallsynthese]]