China and rare earth metals

 

RARE EARTH METALS.  I am not an astrophysicist but they rubs elbows with us nuclear physicsts.  And the nuclear reactions of stars tells why we get rare earths and why they are rare and where found. 

            In most normal type-M stars like the sun, hydrogen nuclei (only a proton) undergoes fusion into the element helium (2 protons, 2 neutrons).  Think of the process as the nucleons (protons and neutrons) sticking together and organizing themselves into a more stable configuration.  A proton can change itself into a neutron by spinning off a positron and a weird little particle that doesn’t react with hardly anything called a neutrino. The new neutron is lighter than the proton.  You still can’t account for all  the loss of mass by the positron and neutrino.  The excess loss is energy by mass conversion, E=mc². Forming Helium is the next  and even more stable step.  The result of a 3 part reaction  of 6 total protons in stages then yields a Helium nucleus (2 protons, 2 neutrons) and releases 2 free protons and a huge amount of energy in the way of gamma rays.  The rays smack around a lot of gas ions on the way out of the sun and so emerge as mostly visible light plus a few gammas and X-rays plus infrared and radio waves—all different wavelengths and energies of light.  The helium of the sun is like a bunch of ash left from this process.  The present sun is 20% helium and the rest mostly hydrogen. 

            So what happens when the hydrogen protons are all burned into helium nuclei? The helium-4’s all start smacking into each other and the star becomes a red giant.  Forming carbon-12, 3 Helium’s can become more stable and more energy is shot off.  Then Carbon undergoes a process that makes Oxygen-16. A further process takes O-16 nucleii into Ne-20.  Another takes Ne-20 into MG-24. Then another process takes Mg-24 into Fe-56.  Notice how all the numbers of nucleons is divisible by 4?  It’s like a periodic chart for nuclei where every 4 nucleons forms a more stable group.  Each successive  reaction gives off more gamma ray energy.  But when a star transforms totally into iron, it has arrived at the most stable kind of nucleus.  There are no further reactions.  But the star then condenses rapidly by gravity until the high pressure and density is unstable and it explodes into a supernova.  That ultra high-energy event causes a couple more reactions to take place jumping and jamming more nuclei together, but in less stable groups.  These are the heavy elements above iron in the periodic table and most are rare earth metals. The time for these formative reactions is minuscule as the star collapses to the max.  That’s why there are so few rare earths or the radioactive trans-bismuth elements (like uranium).  Once the explosion blasts out to about the size of the Sun,  temperatures fall to 4 X 10⁹ degrees Kelvin, and all this heavy element formation quickly stops.  The explosion sends the debris of iron and all the heavies out to the heavens and become raw material for new stars.

            When stars form, they start as a ball of gases under gravitational attraction, much of it hydrogen but also a bit of heavier elements,like iron left from supernovae. Mostly iron in fact.  Inner planets form as they capture of hydrogen, oxygen and this heavy stuff.  But the heat of their environment and the new star’s solar wind drive off a lot of the light gases, leaving a rocky planet.  Out farther, there are colder planets forming and the gases remain-- Jupiter, Saturn, Neptune and Uranus.  Gravity and radioactivity made earth hot and molten in the early days, and heavy elements sank towards the center core due to weight. Earth had the rare event of a Mars-sized planet that smacked into it very early when both planets were hot and molten.  The collision spewed out a molten blast of lighter, earth-crust elements (Si, Ca, Al), but the earth left over was heavy with excess iron as its core. (and surface of early earth was super iron-rich too)The moon collected from the explosive debris of lighter molten crust rocks.  Moon rocks look stunningly like very very old greenstone rocks of the Canadian Shield and thus show their common origin with earth. But Moon, has had no magnetic field from early on—no big iron core.  Earth got all the core iron. With circulation of molten iron, this yields a strong magnetic field which repels asteroids and other interplanetary debris.  Hence earth is protected from many collisions, but Moon is not, and has lots of craters to show for it. 

            Now how do we get rare earths out of the core?  Volcanoes often spew circulating molten magma that is 35 miles down from the crust. This cools and hardens in old volcanic dikes and tunnels which finally get exposed by erosion.  This is all the fun stuff like gold and silver and lead. So where would you go to find most of these deposits?  Himalayas. That’s the biggest upheaval mountain range. Hence China has most of the rare earth mines.  Africa is also a source, especially the ancient volcanics of South Africa.  But there are other places. That’s the dilemma of finding and using rare earths for making batteries—you have to deal with China who have made themselves the smelter/refiner of rare earths.  And it takes years to develop this industry. The mining waste is toxic and pollutes.  Lithium, on the other hand, is a light element but found almost exclusively in the Atacoma desert (s. America) which is extraordinarily dry.  Lithium reacts violently with water, so in a wet place it quickly reacts and dissipates into the earth.

        Much of the research into battery technology has gone into trying exotic materials, rare earths.  Batteries are needed for EVs.  Big batteries. If the world begins to use massive numbers of EVs it means the price of rare earths will skyrocket, perhaps as much as 20 X higher.  That would make an EV a rich man's toy and would make the price of all those gadgets and home tools which use batteries prohibitively expensive.  China has gone all over the world with their Belt and Road foreign aid which in turn demands a share of that country's production of any rare earths found.  It's the foreign policy equivalent of "cornering the market" in the commodities business. Of course, some third world country who is so taken advantage of will still be behind, using gasoline and diesel.  It also explains why, if you are a liberal who wants green energy vehicles, you are in bed with China they way the Biden syndicate is.