mercury-sodium amalgam

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I am a newbee, so here it goes:

What is the purpose of the mercury in the standard aluminum amalgam? Is it just to expose non-oxidised material as it is consumed? What happens to the mercury?

I hear sodium makes a nice reducer. I first learned of the electrolytic amalgamation with sodium metal on a gold mining website (!), where they used it to make "activated mercury" to strip oxide coatings off gold chips and keep mercury nice and clean. The beauty of the process seems to be that the mercury can be reused. I like the mercury reduction, except for the mercury part! If the mercury can be reused, I can deal with it. If it can't, I have a hard time justifying the heavy metal waste to myself. On the mining website, they talked about regenerating the mercury in the electrolysis cell whenever it "lost its magic". Could the same be done?
And where does the oxygen go? The sodium/aluminum/lithium grabs it?

Let me know if this should be in stimulants....

[Rhodium]

https://www.thevespiary.org/rhodium/Rhodium/chemistry/alhg.osmium.html

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2You meant "the other FSE"...
So let me see:
Mercury reduces aluminum
Aluminum reduces MP2P/P2P/whatever

this right?

So Hg02 or something is formed, I guess.

Would it be possible to make an electrochemical cell to electrically reduce the aluminum, avoiding the need for mercury?

Can another metal be substituted for mercury, stealing oxygen from the aluminum, like the anticorrosion sacrificial anode described in the link you gave me?

In a sodium cell, does the mercury serve the same function, or is it needed? If the mercury can be reused, or is unnecesary, I can imagine this to be verrry useful.

Is mercury soluble in NH₃? If not, could a sodium amalgam be made by electrolysis of NaOH, then dropped in a birch cell, then the undissolved mercury picked out afterwards to be reused?

The reference you pointed me to says that electrolysis of NaCl gives very little hydrogen production. I assume this means it only liberates chlorine. I see a good use for this in generating chlorine for bubblers.

Thanks for taking the time to answer the silly questions of a dreamy bee...

[Rhodium]

You meant "the other FSE"

No, the document on my page is an old Hive Post, it's just that the formatting is better in the document at my page.

Mercury reduces aluminum
Aluminum reduces MP2P/P2P/whatever

this right?

No. Rather that the Aluminum reduces the Hg²⁺ to Hg, which dissolves in the outer aluminum layers, forming a mercury alloy (amalgam), which is superior as electron transfer medium.

So Hg02 or something is formed, I guess.

No, elemental mercury is formed. HgO₂ does not exist.

Would it be possible to make an electrochemical cell to electrically reduce the aluminum, avoiding the need for mercury?

Yes, but when when doing this, you can even take the aluminum out of the equation, making a current-powered electrolytic reductive amination cell:

An Electrochemical Reductive Amination Method

(https://www.thevespiary.org/rhodium/Rhodium/chemistry/electroreductive.amination.html)

With Hg, but without Al:

Electrochemical Reductive Amination of P2P's over a Mercury Cathode (PDF)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/redamin.hg-cathode.pdf)

Can another metal be substituted for mercury, stealing oxygen from the aluminum, like the anticorrosion sacrificial anode described in the link you gave me?

No.

In a sodium cell, does the mercury serve the same function, or is it needed? If the mercury can be reused, or is unnecesary, I can imagine this to be verrry useful.

Yes, it is needed, that's why it is used (duh). The mercury from any amalgam reduction can be re-used (after purification).