Use of anti-oxidants when milling to reduce chance of runaway redox?

[jeffreyschultz]

I know the rule is to never mill metals, but Im sitting here at work with my mind running off in its own direction. So for the sake of a good academic/hypothetical argument...

 

Would it be plausible that you could introduce an anti-oxidant into the mill with another risky reducer, such as Al or Mg, that could potentially take the brunt of a limited amount of oxidation, that otherwise could have potentially resulted in a runaway redox across the material and the possibility of injury. Anti-oxidants are often reducers themselves that more easily oxidize, and act as sacrificial components, such as the sacrificial anode on boats to protect the propellor. This is assuming there is also a coating compound, such as stearin, being milled alongside the material to further reduce the chances of oxidation. One such anti-oxidant that comes to mind is ascorbic acid. I know this addition would hinder its subsequent usage, but I am guessing this technique is probably applied when adding stabilizers to compositions.

 

I am new to the scene, so appease my curiousity.

Edited August 29, 2013 by jeffreyschultz

[Mumbles]

I doubt that would work. Industrially, they just mill in an inert gas environment. There are two factors at play here. Kinetics, how fast something will reduce, and thermodynamics, how favorable it is to reduce. While ascorbic acid will oxidize relatively easily, it does not react with atmospheric oxygen and it is not nearly as strong of a reductant as magnesium or aluminum. What you actually need is something that would preferentially oxidize and eat up the oxygen quickly as opposed to the metal you're trying to mill. I assure you there are only a few things that reduce more strongly than magnesium and aluminum, and most of them are not viable options.

 

The real danger isn't really in the milling process. The exposed metal will quickly oxidize and make a highly reduced environment inside the jar. The biggest issue, at least on the hobbyist scale, is when the mill is opened and all that freshly exposed metal is allowed to react with the air. If too much air is allowed into the container, it can easily have a runaway reaction and light on fire.

[boule]

The whole point of "antioxidants" is to catch free radicals that are generated in different biochemical processes and will also intercept low quantities of oxidizing agents. Unfortunately as mumbles pointed out, the issue in pyro is not oxidizing agents causing the runaway reaction but rather oxygen coming in contact with a very reactive surface. You would need to change the surface of the freshly broken up metal by slow oxidation in order to avoid accidents and - as mumbles pointed out - using an inert gas with just a tiny bit of oxgen left in the mix will suffice for that.

[ollie1016]

I've heard that if you mill Al , with charcoal powder , it stops/ reduces the Al oxidising?