Accelerating Future Transhumanism, AI, nanotech, the Singularity, and extinction risk.

8Jan/1056

Our Friend Gadolinium

Brian Wang directs our attention to one important part of Rob Freitas' radionuclide page:

The mass of the alpha-particle is ~7000 times greater than that of an electron, so the velocity and hence the range of a-particles in matter is considerably less than for beta-particles of equal energy. Consequently the optimum radionuclide for medical nanorobots is predominantly an alpha emitter.

Among all gamma-free alpha-only emitters with t1/2 > 106 sec, the highest volumetric power density is available using Gd148 (gadolinium) which a-decays directly to Sm144 (samarium), a stable rare-earth isotope. A solid sphere of pure Gd148 (~7900 kg/m3) of radius r = 95 microns surrounded by a 5-micron thick platinum shield (total device radius R = 100 microns) and a thin polished silver coating of emissivity er = 0.02 suspended in vacuo would initially maintain a constant temperature T2 (far from a surface held at T1 = 310 K)

75-year half-life, initially generating 17 microwatts of thermal power which can be converted to 8 microwatts of mechanical power by a Stirling engine operating at ~50% efficiency. (Smaller spheres of Gd148 run cooler.) While probably too large for most individual nanorobot designs, such spheres could be an ideal long-term energy source for a swallowable or implantable "power pill" (Chapter 26) or dedicated energy organ (Section 6.4.4). A ~0.2 kg block of pure Gd148 (~1 inch3) initially yields ~120 watts, sufficient in theory to meet the complete basal power needs of an entire human body for ~1 century (given suitable nucleochemical energy conversion and load buffering mechanisms, and a sufficiently well-divided structure).

The last part is the punchline, of course. Freitas acknowledges future design challenges such as energy conversion, load buffering, and division of structure. If these challenges are overcome, a large block of Gd148 (or simply gadolinite ready to be processed into pure gadolinium) could supply nutrition to millions of people for millennia. Gadolinium has a half-life of 75 years, so you'd need double as much for each 75-year period you wish to avoiding refueling for, but storing gadolinium in its stable gadolinite form seems avoid this problem. Unfortunately, gadolinite is fairly rare and gadolinium itself is only found in the Earth's crust at a 6.2 ppm level. By comparison, the abundance of gold in the Earth's crust is only 0.0011 ppm. According to this page, annual production of gadolinium is 200 tons.

Just to throw some numbers out there, if one cubic inch is enough per person per century, a million people would require a million cubic inches. That can fit in a cube 9 x 9 x 9 ft large. According to Freitas' numbers, this would weigh about 200,000 kg, or 200 metric tonnes, which is on par with today's annual production. If demand for gadolinium grew, it seems plausible that its cost would fall greatly -- after all, gold is about 6,000 times rarer and our annual production is 2,800 tons. Feeding ten billion people with gadolinium, if that were possible, would require about 2,000,000 metric tonnes for the first century. At an extraction rate of 200,000 metric tonnes per year, it could be done in a decade. This would require increasing current production by a factor of 1,000. According to this book, gadolinite can contain 40% rare earth oxides, 5% of which consists of gadolinium itself. That means that gadolinium makes up about 2% of the total. (Wrong: see comments.) Processing ten million metric tonnes of the ore annually would yield the required amount. For comparison, we extract 1.2 billion tons of iron from the Earth's crust annually.

Update: all of the above is wrong for one reason or another, as pointed out in the comments, but at least I had fun. I was confusing chemical stability with nuclear stability and made the mistake that I thought gadolinium-148 would be nuclear-stable in its gadolinite form, which is wrong. The atomic number of gadolinium is 64 meaning that gadolinium-148 contains 20 extra neutrons above neutron-proton parity. It seems to me that we'd eventually have to find a less safe and cheaper isotope to make this work on a large level if it's suitable in practice and we ever want to.

Comments (56) Trackbacks (0)
  1. From WP: “Gadolinium is never found in nature as the free element, but is contained in many rare minerals such as monazite and bastnäsite. It occurs only in trace amounts in the mineral gadolinite, which was also named after Johan Gadolin. The abundance in the earth crust is about 6.2 mg/kg.[2]”

    “Monazite sand deposits are inevitably of the monazite-(Ce) composition. Typically the lanthanides in such monazites contain about 45 – 48 % cerium, about 24% lanthanum, about 17% neodymium, about 5% praseodymium, and minor quantities of samarium, gadolinium, and yttrium.”

    On Bastnasite: “The composition of the lanthanides was about 49% cerium, 33% lanthanum, 12% neodymium, and 5% praseodymium, with some samarium and gadolinium.”

    The main economic issue would appear to be refining Gd, since it exists in such trace amounts. Uranium is much more abundant and more abundantly mined than Gd (“The worldwide production of uranium in 2006 amounted to 39 655 tonnes”), but “[i]n nature, uranium atoms exist as uranium-238 (99.284%), uranium-235 (0.711%), and a very small amount of uranium-234 (0.0058%),” and 235-U is what it needs to be purified down to. That would be the expensive and difficult part. Gold is cheaper and easier to refine, even though we only mine 2800 tons (compared to 40,000 tons of uranium) because it’s much more pure when it comes out of the ground.

    Michael says: “If demand for gadolinium grew, it seems plausible that its cost would fall greatly”

    Not sure what economics you’re using there.

  2. MZ, ceteris paribus, increased demand leads to increased price. Importantly, increased demand does not necessarily lead to increased cost. Economies of scale and technological innovation (due to industry growth) can mitigate cost and counteract the price increase. However, there’s the supply problem too! If there isn’t much gadolinium or it becomes increasingly hard to obtain, price will increase.

    Anyway, this is all very strange for other reasons. First, this idea does not eliminate eating, because nutrition is still necessary. Second, to do this for one person is very expensive, even for a futuristic idea. Using Michael’s numbers, it’d have cost the entire world GDP in 2006 to obtain the gadolinium for one person. That’s not including the as yet unknown costs of the nanorobots, the surgery, etc… Furthermore, not only must total cost be considered but also relative cost- that is how this procedure compares to simply eating and paying for groceries. New futurist technologies are likely to make food cheaper at a fast rate too, so the “future technologies will make this cheaper” wildcard does not automatically help. It’s hard to say when or if this procedure would be competitive, even were it not so costly. From my standpoint, there’s too many variables.

    At any rate, this is highly speculative but very interesting.

  3. Michael, this is all very interesting, but the gadolinium one mines from the ground doesn’t contain any of the nuclide Ga148 at all (for the obvious reason that it is radioactive with a rather short half-life). I believe that you make Ga148 by spallation, by hitting a tungsten block with a proton beam from an accelerator (such as the advanced neutron source at Oak Ridge). I doubt if you could make more than a few grams a year, even if you did nothing else with your accelerator.

  4. I am usually to blogging and i really admire your content. The article has actually peaks my interest. I am going to bookmark your web site and preserve checking for new information.

  5. This really is precisely what I was searching for, thanks

  6. Greetings! Quick question that’s entirely off topic. Do you know how to make your site mobile friendly? My website looks weird when browsing from my apple iphone. I’m trying to find a template or plugin that might be able to correct this problem. If you have any recommendations, please share. With thanks!

  7. Just to inform you about your web site looks a bit bit unusual in Firefox on my small notebook using Linux .

  8. Great goods from you, man. I’ve understand your stuff previous to and you’re just too great. I actually like what you’ve acquired here, really like what you are stating and the way in which you say it. You make it enjoyable and you still care for to keep it wise. I can’t wait to read much more from you. This is actually a wonderful site.

  9. My spouse and I stumbled over here from a different website and thought I might as well check things out. I like what I see so now i am following you. Look forward to finding out about your web page repeatedly.

  10. You should take part in a contest for among the finest blogs on the web. I’ll recommend this web site!

  11. You will get so significantly terrific specifics with this unique web-site. It is fun to discover a service which may please a lot of people today. Carry around the good work!

  12. Just wish to say your article is as surprising. The clarity on your post is simply excellent and i can suppose you’re an expert in this subject. Well together with your permission allow me to take hold of your RSS feed to keep up to date with coming near near post. Thank you 1,000,000 and please carry on the enjoyable work.

  13. What’s up, all right brother there are certainly multiple blogging web pages, but I recommend you to use Google’s without charge blogging services.

  14. Nearly all women want to have greater, tighter along with fuller bosoms. Still, not almost all girls are blessed with these breasts this is exactly why they look for ways to realize their desired breasts. Instead associated with undergoing those costly along with high-risk breasts enlargement surgery, why not make use of natural busts enhancement? This requires consuming products, using lotions, or maybe performing exercises that will help you attain greater, tighter along with fuller bosoms the better way.

  15. Amazing! Its really amazing paragraph, I have got much clear idea concerning from this post.

  16. I’m impressed, I have to admit. Seldom do I encounter a blog that’s both equally educative and engaging, and without a doubt, you have hit the nail on the head. The issue is something which not enough people are speaking intelligently about. I’m very happy that I found this during my hunt for something concerning this.

  17. Interessantes Thema. Bin aber nicht ganz deiner Meinung, aber das ist ja auch kein Forum hier. Bleib am Ball.

  18. You’ve got noted extremely fascinating details ! ps decent web site.

  19. I appreciate you taking the time to create this post. It has been really valuable to me surely. Value it.

  20. Hey there, or perhaps may well be away from problem rather regardless, i surfing surrounding your internet-site also seems essentially truly expert. I’m also creating a new-found blogging internet site because trying to cope to create it bode effectively, each i’ve addition couple of items since i mess it up. In which way painful was 1st the internet site to develop your site? Could maybe one as i am without the suffer from do it appropriate, to fit cherished ones modify documents without having to wrecking the application training?

  21. I did however expertise some technical issues using this website, since I experienced to reload the website lots of times previous to I could get it to load properly. I had been wondering if your hosting is OK? Not that I’m complaining, but sluggish loading instances times will often affect your placement in google and could damage your quality score if advertising and marketing with Adwords. Anyway I’m adding this RSS to my e-mail and could look out for a lot more of your respective exciting content. Ensure that you update this again soon..

  22. The Twitter application page will open. This really is great if you’ve got some thousand followers, but as you get far more and much more the usefulness of this tool is downgraded.

  23. An intriguing discussion is definitely worth comment. There’s no doubt that that you need to write more about this topic, it may not be a taboo matter but generally folks don’t speak about these subjects. To the next! All the best!!|

  24. Whats rough now is how the programmed appear to ones life will not be modified. This may sound confusing? It’s virtually as if we blitz by means of our lives with blinders on, not accepting the accurate which means of our own existence.

  25. hey there and thanks to your information – I have certainly picked up anything new from proper here. I did on the other hand experience a few technical points the usage of this web site, since I experienced to reload the web site many instances previous to I could get it to load correctly. I were thinking about if your web host is OK? No longer that I’m complaining, but slow loading cases times will often have an effect on your placement in google and could damage your high-quality ranking if ads and ***********|advertising|advertising|advertising and *********** with Adwords. Anyway I’m adding this RSS to my e-mail and could glance out for a lot extra of your respective exciting content. Ensure that you replace this once more soon..

  26. Superb learn, I only passed this onto a colleague who was in search of this info. Ive you bookmarked on Digg.

  27. Outstanding post, I believe blog owners should larn a lot from this blog its very user pleasant.

  28. I’ve recently started a web site, the information you offer on this site has helped me greatly. Thanks for all of your time & work. “The word ‘genius’ isn’t applicable in football. A genius is a guy like Norman Einstein.” by Joe Theismann.

  29. Nice read, I just passed this onto a friend who was doing some research on that. And he actually bought me lunch since I found it for him smile Thus let me rephrase that: Thank you for lunch! “Without friends no one would choose to live, though he had all other goods.” by Aristotle.

  30. Greetings! I’ve been reading your web site for a long time now and finally got the bravery to go ahead and give you a shout out from New Caney Tx! Just wanted to mention keep up the excellent job!

  31. Whenever that got to games, in excess of your few of my own gamer buddies admitted to acquiring slept up all day playing texas holdem. Several owned or operated high-end holdem poker chip sets and additionally planned their routines all-around their monthly online poker video games.

  32. Thanks for the tips on credit repair on this particular site. A few things i would advice people will be to give up the actual mentality they will buy today and shell out later. As being a society many of us tend to make this happen for many things. This includes getaways, furniture, in addition to items we wish. However, you need to separate your wants from all the needs. When you are working to boost your credit score make some trade-offs. For example you’ll be able to shop online to economize or you can visit second hand suppliers instead of costly department stores intended for clothing.

  33. Nice post. I learn one thing tougher on completely different blogs everyday. It can always be stimulating to learn content from other writers and apply a little one thing from their store. I’d want to make use of some with the content on my blog whether or not you don’t mind. Natually I’ll provide you with a hyperlink on your web blog. Thanks for sharing.

  34. Presently there weren’t almost any bridge online players in the set, however , several brought up learning old-time games off their parents and even grandpa and grandma. The adoringly reminisced about trying to play card games with cesta, rummy, paper hearts, together with spades because they were being when i was youn.

  35. You will need to consider 2 stuff for you to figure out the very advantages regarding carpet cleaning fitness equipment.

  36. Car port home replacing possesses at the same time also been scored as the leading house developments by just typically the 2010-11 Charge vs .. Benefits Record. This unique statement programs some superb 84 percentage go back in financial commitment, getting this the particular inside and second status for those dwelling development work, minute simply to top gate renewal within RETURN ON YOUR INVESTMENT.

  37. Hey there! This is kind of off topic but I need some help from an established blog. Is it hard to set up your own blog? I’m not very techincal but I can figure things out pretty fast. I’m thinking about making my own but I’m not sure where to begin. Do you have any tips or suggestions? Many thanks

  38. I’m not sure where you are getting your info, but great topic. I needs to spend some time learning more or understanding more. Thanks for magnificent information I was looking for this information for my mission.

  39. Have you ever thought about including a little bit more than just your articles? I mean, what you say is valuable and everything. Nevertheless think about if you added some great visuals or video clips to give your posts more, “pop”! Your content is excellent but with images and video clips, this website could undeniably be one of the greatest in its field. Very good blog!

  40. Thanks for the auspicious writeup. It in truth was a leisure account it. Look complicated to far delivered agreeable from you! By the way, how can we keep up a correspondence?

  41. After research a couple of of the weblog posts on your web site now, and I really like your means of blogging. I bookmarked it to my bookmark website record and might be checking again soon. Pls check out my site as properly and let me know what you think.

  42. Hey! I simply wish to give a huge thumbs up for the nice info you will have here on this post. I shall be coming back to your blog for extra soon.some tips here!

  43. I’m impressed, I must say. Really hardly ever do I encounter a blog that’s each educative and entertaining, and let me let you know, you may have hit the nail on the head. Your concept is outstanding; the problem is one thing that not enough persons are speaking intelligently about. I am very comfortable that I stumbled across this in my search for one thing relating to this.some tips here!

  44. Can I simply say what a aid to search out someone who actually is aware of what theyre talking about on the internet. You undoubtedly know methods to bring a difficulty to mild and make it important. More folks need to read this and understand this side of the story. I cant believe youre no more widespread since you definitely have the gift.Useful info!

  45. Good post. I study something tougher on different blogs everyday. It should all the time be stimulating to read content from other writers and observe slightly something from their store. I’d choose to use some with the content on my blog whether or not you don’t mind. Natually I’ll offer you a link in your net blog. Thanks for sharing.Useful info!

  46. An fascinating dialogue is worth comment. I think that you must write extra on this subject, it may not be a taboo topic but typically people are not sufficient to speak on such topics. To the next. Cheers

  47. That is the appropriate blog for anybody who needs to search out out about this topic. You understand so much its almost laborious to argue with you (not that I really would want…HaHa). You undoubtedly put a new spin on a topic thats been written about for years. Great stuff, simply nice!some tips here!

  48. There are actually a whole lot of details like that to take into consideration. That could be a great point to carry up. I provide the ideas above as common inspiration however clearly there are questions just like the one you carry up the place an important factor can be working in trustworthy good faith. I don?t know if greatest practices have emerged around issues like that, however I am positive that your job is clearly recognized as a good game. Both boys and girls really feel the affect of only a moment’s pleasure, for the rest of their lives.

  49. It’s exhausting to search out knowledgeable people on this matter, however you sound like you understand what you’re speaking about! Thanks

  50. Unquestionably believe that which you said. Your favorite justification appeared to be on the web the easiest thing to be aware of. I say to you, I certainly get annoyed while people think about worries that they plainly don’t know about. You managed to hit the nail upon the top and defined out the whole thing without having side-effects , people can take a signal. Will likely be back to get more. Thanks

  51. Enormously educational many thanks, I do believe your visitors will most likely want further blog posts similar to this maintain the excellent effort.

  52. I’ve learn a few excellent stuff here. Definitely price bookmarking for revisiting. I wonder how a lot effort you put to create any such wonderful informative site.

  53. Dr. Pollack has practiced general & cosmetic dentistry in New Jersey for over 35 years, having helped thousands of patients regain confidence in their smile. “I like to say that while my patients smile more after seeing me, I smile more because of my patients.” Dr. Pollack is committed to modern, eco-friendly dental care for patients of all ages, tailoring his approach and treatment accordingly to each patient. “We invest in the best dental equipment possible, equipment which we’ve seen can deliver reliable results for our patients.”

  54. Dr. Pollack has practiced general & cosmetic dentistry in New Jersey for over 35 years, having helped thousands of patients regain confidence in their smile. “I like to say that while my patients smile more after seeing me, I smile more because of my patients.” Dr. Pollack is committed to modern, eco-friendly dental care for patients of all ages, tailoring his approach and treatment accordingly to each patient. “We invest in the best dental equipment possible, equipment which we’ve seen can deliver reliable results for our patients.”


Leave a comment

No trackbacks yet.