Hi, http://www.daughtersoftiresias.org/greenwiki/Peak_lithium makes clear that there is ample Lithium in the Earth's crust. The minimum figure given is 20 ppm by weight, which results in a total quantity of 3.3E18 kg. It may not be economical to extract this for batteries, but if we consider the fusion energy that it represents, then that works out to 1260 kWh/kg of "dirt", which compares very favourably to 8.2 kWh/kg for anthracite and 14 kWh/kg for gasoline, and we consider both of these to be very worth while "mining" for their energy. However the latter are already "pure" when extracted. Therefore let the cost of chemical extraction of the Li be e.g. 3 eV / atom of dross that needs to be thrown away (probably a gross overestimate). Because Lithium is one of the lightest elements, we can be fairly safe in assuming that the atomic % will be at least 20 ppm. Therefore the ratio of dross atoms to Li atoms is at most 50000:1. 50000 * 3 eV is 150000 eV which is less than 1% of the 16.3 MeV fusion energy / Li atom. This means that less than 1% of the energy content is required to extract the Li from dirt. Even if we assume electrical energy is required for the separation, and the conversion rate is 33%, this only rises to less than 3%.
In short ordinary dirt is about 87 times more energy dense than gasoline, and about 150 times more energy dense than anthracite (only considering the Li content). The Lithium reactions are particularly interesting for several reasons:- 1) They use ordinary Hydrogen (not deuterium), so no neutrons are produced. 2) The only end product is harmless Helium. 3) In both reactions, the products are "slow", heavy, doubly charged particles with a very short range (microns) in solids or liquids. This makes for a very safe energy source. i.e. Li7 + H -> 2 He4 + 17.3 MeV Li6 + H -> He4 + He3 + 4 MeV Li7 is 92.6%, Li6 is 7.4% of natural Lithium. This yields an average of about 16.3 MeV / atom of natural Lithium. These are clean reactions, which produce no radioisotopes, and no neutron contamination of the equipment (unless the H is contaminated by D). Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/Project.html
