aluminium + sodium hydroxide + water = aluminium hydroxide???? help please

[Hydro-Cell]

hi
hopefully someone with more brains than me can answer this question more scientifically.

basically i have built a rector that uses aluminium powder, sodium hydroxide and water to produce vast amounts of hydrogen.

now heres the problem, i am told that unless the aluminium and sodium hydroxide are mixed in the correct proportions there are a few problems.

1: far too much heat is produced.
2: aluminium salts are produced (not sure which)
3: the geatinous aluminium hydroxide that should be produced is redisolved by excess sodium hydroxide  (too many reactions for my liking)

now then for the question,

can anyone use the chemical formula for this reaction to determine what amounts of aluminium and sodium hydroxide should be mixed. im guessing you can add as much water as you like...

also i have always wondered, if you mix aluminium with sodium hydroxide you get aluminium hydroxide, where does the sodium go??? the chemical formula iirc shows the sodium bonded with the aluminium hydroxide but its not mentioned in the name (so to speak)

any help would be great guys

[hansvonlieven]

G'day Hydro-Cell,

Send a personal message to Dave ( ResinRat2 ), He is our resident research chemist. He will explain the chemical reaction to you.

Hans von Lieven

[Dave45]

If you got this working how long would it take before aluminum got too scarce and expensive to use.

[ramset]

DAVE
A lot of towns in the USA have started land filling recyclables [no longer cost effective]
Chet

[Creativity]

nothing will happen in this mixture at all.Sodium is more rective than aluminium and won't give out OH to it.

uppps,i was wrong to some extent there will happen some things but i was correct that Na won't give its OH group away

ok i took my dust chemistry book from the shelf..

NaOH will uncover the Al surface so it can react with water:

1) Al2O3+2NaOH+3H2O====>2Na[Al(OH)4] (salt solvable in water)

Water reacting with Al:

2) 2Al+6H2O===>2Al(OH)3+3H2


as next step Al(OH)3 is further bond into salt:

3) Al(OH)3+NaOH===>Na[Al(OH)4]

The thing to accent is than Al is always covered by its oxide,so if u have Al powder it is in fact Al surrounded by Al2O3.
So in first step NaOH solves the Al2O3,then Al under it reacts with water to produce Al(OH)3.The latest one gets again turned into salt by NaOH.
The finer the powder the more NaOH will go to eat the Al2O3.So this part of the reaction depends on the surface area and the tickness of the Al2O2.If we consider this powder as sphere-like formation,the Al wil make most of its mass,so i would negate the first reaction needs.U can also take the experimental value like +5% of what u need for reaction 3 to be completed.

Without the first reaction in the consideration,for ideal reaction u need for every 54 gram of Al ,80g of NaOH.

In first reaction for every 102g of Al2O3 u need 80g of NaOH.

i see resinrat was faster by 2 minutes