All/hg Stall, AI question

[Gale]

All test runs have worked OK but scale-up with Ai "Sheet" has been weird. First off on a big reduction I used magnetic metal and.didn't realized this until near the end if the rxn.. So now on redo rxn I think the ai "sheet" I chose is much too thick. It came from an Ai broom/pole. It was thick, but I managed to cut it up with scissors. The reaction went very slow, heated to 45-60c for like 6 hours with vigorous agitation/ swirling. Didn't seem to do much, maybe very very slowly. Over time and mostly at the 10 hour mark naoh solution was added and the reaction started heating up, and kept itself at around 35-50c for a few hours now.

 

[WillD]

In some cases, we can use aluminum granules, but this also takes more time.

 

[Gale]

Ya I tried with baking pans and exothermic reaction took place it went up to 65c, with improvised stirring by swirling bucket most of the time... Seems like this doesn't do anything but it seems like everything is mixing and can hear the All scraping along.. Problem is there was tons of unreacted aluminum using osmiums calculations plus 10% excess. I think I have to downgrade to foil for these 2-300g reductions or cut my pie pans finer or maybe get some good CNC shavings.

The foil mostly went away after basifying but idk if that matters. Lyk how it goes.

 

[WillD]

You must use an excess of mercury salts in water and not decant it from the reaction, then aluminum will react (but for a long time). Try it.

 

[Gale]

I used excess mercury. I use osm method by amalgamating in methanol. I waited like 45-60 mins and it was all silvery and methanol had a grey/silvery appearance. I used osmiums mercury calculations plus excess. Maybe 1.5x what osmium reccomended. Seems to work OK by the looks of the Al mixture, tiny bubbles and solution turns silvery/grey. Only noticed a few small pieces of pie pan floating

On the latest reaction the mixture went to 65c on its own in a large vessel, if it was appropriate size, maybe would have gone to 70-75 without cooling. The exothermic reaction lasted around 90 mins, then gradually the temps fell.. brought to 55c for 4 more hours.. a large amount of Al pie pan was left over osmium calculation + 10% excess...still way to much Al left over. I think its mainly due to terrible stirring procedure..so I will get on top of that. Osmium did mention a few times how important it is to have proper stirring is, especially for larger reactions..

 

[WillD]

Can you tell you more about this method?

 

[dark_side_of_chemistry]

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