Silver Science - Hydrogen from Waste

    • Official Post

    Triethanolaminme (TEA) is used in some processes with this material. But I have found something that seems more effective and is also less able to bind to the hydroxide. Here you see two very similar samples -the one on the left is relatively pure aluminium, the one on the right is aluminium alloy with around 2.5% Cu - see how the copper is being solubilised giving a greenish tinge to the contents of the beaker.


  • Alan Smith i understood that impurities inside hydroxides were especially from another metals unexpected.

    Why only few of these impurities could disturb the mix because aluminium or copper, what is the difference ?

    Is there a market for some hydroxides which aren't focused on these impurities ? At other side, what are customer who need a very pure product, for example ?

    • Official Post

    The market for aluminium hydroxide is huge, over 70M tonnes/yr. It embraces all levels of purity too, from very impure 'brown hydroxide' with higher levels of Iron which are used for making Abrasives to 99,999% purity which is used in the process of making artificial gemstones. In between various purity and particle size types are used in catalysts, ceramics, refractories, dielectrics fireproofing, water treatment and cosmetics. The most valuable is 99.999% pure nano-hydroxide which can cost between €50 and €5000/kg depending on the exact crystalline structure..

  • Nothing about aluminium is actually clean as its production inherently consumes lotta carbon by itself. It makes it different from alternative processes, which recommend to make fuel from surplus of solar + wind plant production. In addition, production of hydrogen from aluminium is very wasteful because lotta additional heat gets produced and wasted during it. At third, resulting voluminous aluminium hydrate slurry is way more difficult to recycle than common aluminium scrap. At forth, the usage of rare metal silver as catalyst would not improve the economy of this process definitely.

  • Zephir_AWT AWT.

    You don't really get it. But not to worry, many people don't.

    1. Additional heat (or 'process heat' as it is correctly called) is not wasted if you design a plant to make use of it.

    2. Aluminium Hydroxide is not difficult to recycle, because it does not need to be recycled into aluminium, instead it gets sold into a multi-million ton market for hydroxide - used in fireproofing, ceramics etc. And used that way it actually reduces the need to mine and refine more.

    3. The USA and EU combined landfill 5 Million tonnes a year of scrap aluminium because (amongst other reasons) nobody wants to resmelt the small stuff. Too hard, too expensive, too polluting. The process I developed is aimed at using that 5M tonnes to displace the mining and refining of 40M tonnes of bauxite clay dug up just to serve the hydroxide market. The hydrogen is a bonus.

    4. Silver metal? I don't use it.

  • How green is blue hydrogen? Far from being low carbon, greenhouse gas emissions from the production of blue hydrogen are quite high, particularly due to the release of fugitive methane.

    For our default assumptions (3.5% emission rate of methane from natural gas and a 20-year global warming potential), total carbon dioxide equivalent emissions for blue hydrogen are only 9%-12% less than for gray hydrogen. While carbon dioxide emissions are lower, fugitive methane emissions for blue hydrogen are higher than for gray hydrogen because of an increased use of natural gas to power the carbon capture.

    Perhaps surprisingly, the greenhouse gas footprint of blue hydrogen is more than 20% greater than burning natural gas or coal for heat and some 60% greater than burning diesel oil for heat, again with our default assumptions. In a sensitivity analysis in which the methane emission rate from natural gas is reduced to a low value of 1.54%, greenhouse gas emissions from blue hydrogen are still greater than from simply burning natural gas, and are only 18%-25% less than for gray hydrogen. This analysis assumes that captured carbon dioxide can be stored indefinitely, an optimistic and unproven assumption. Even if true though, the use of blue hydrogen appears difficult to justify on climate grounds. See also:

    Carbon tax and "renewables" only make impact of climatic changes worse 1, 2, 3, 4, 5, 6...

  • Aluminium Hydroxide is not difficult to recycle, because it does not need to be recycled into aluminium, instead it gets sold into a multi-million ton market for hydroxide - used in fireproofing, ceramics etc.

    Communal aluminium scrap contains lotta iron, copper: Al 3004 (0.7% Fe, 0.25% Cu) / Al 5182 (0.3 Mn). Another copper comes as an dissolution catalyst. Fireproofing maybe, but how this mess can be used in ceramics?

  • I see... How expensive are these? Removing iron, copper, manganese from ceramic raw materials isn't cheap neither easy.

    The answer is, they are non-toxic, green - being derived from low-energy fermentation processes, and since they are already manufactured in bulk inexpensive. Amazing what you find out when you spend some years studying it.