It would appear that this is a mechanism for converting kinetic motion of the aqueous solution into electrical energy. This is essentially the same thing that a water wheel does, with the associated issues of being able to supply sufficient flow of water in order to get any serious amounts of energy out.
Hamil - like submarines and high rise buildings there is nowhere to easily run to if a fire does break out so safety is definitely another key point in VRFB's favour. Do we know anyone who builds ships ?
That ferry uses a 4.3MWh battery (from Leclanche not Lechanche as stated in the article) - compare this with our 450kWh battery at Eskom - that is a 20 foot container size. So roughly 4.5 container sizes if you use VRFBs. Obviously it would be smaller if you built it into the ship instead of packaged it within containers. I'm not sure the same approach can be used with Lithium-ion batteries, not without risking that a fire might not be containable.
Personally I don't think that many mobile applications suit VRFBs (historical golf carts excepted). The weight is not the issue per se, as if you use regenerative braking then the extra energy you have to put into getting the battery moving is offset by the extra energy you can put back into it when you slow down. Also the size is not so much the issue, in eg the train situation, as having to have 1 full carriage stuck on the back of the train is not significantly worse than having to put half an extra carriage on the back of the train. No I think it is actually the vibration that is the VRFB killer for trains.
Sloppy - no doubt they are but it will be a long slog for them and the question is how much work do they have to do before they can get to that material. I'm struggling to see where they get their x30 upgrade factor from.
Following on from this - if they mine 500,000 tonnes of ore per annum, grading 0.2% Tin, and recover 70% of this in processing you end up with 700 tonnes of tin a year.
Assuming a tin sale price of USD 16,000 per tonne, normal production cost of $15,000 per tonne and Tantalum credits of USD 10,000 per tonne you get USD 11,000 per tonne gross profit. That works out at 7.7 Million USD per annum - for a company currently valued at only GBP 22M
SoTRR and ojt333 - you are correct that Tantalum is quoted as being priced around $150,000 per tonne. What is not immediately clear is whether this price is for the Tantalum contained in Tantalum oxide ores or if it is for a tonne of Tantalite (Ta2O6 - 79% by weight Tantalum) in which case you only get 0.79 Tonnes of Tantalum for your 150 grands worth of Tantalite.
[I have some doubt about whether the company is referring to Tantalite, mentioned in their presentations, which is apparently an old name for (Mn,Fe)Ta2O6 or Ta2O5, or tantalum pentoxide, which is the formula shown in their presentations.]
The first mention of Tantalum was in connection with the other original sites ML133 and ML129 which both quoted 0.015% Ta2O5 - this is 150 parts per million (PPM).
More recent drilling of the V1,V2 zones at ML134 show Ta levels of between 77ppm and 129ppm - again the issue is are these figures directly comparable with each other or is ML133 and ML129 the ppm by weight of Ta2O5 whilst the newer figures might be actually the ppm weight of Ta (Ta2O5 is 82% by weight of Tantalum) - if so then the 150ppm and 129ppm figures work out very similar to one another.
The bottom line is if Tin is 0.2% and Tantalum is 0.015% then there will be approximately 1/13th as much Tantalum recovered as the tin. This could effectively knock 10,000 USD per tonne off the production price of the Tin.