Can metals be seperated by distillation?

Question

Was probably looking at mixture of copper, zinc, and aluminium.

Answer 1

Yes, it can be done, no question.  The trick to make it easier is to use vacuum, as you noted in your additional details.  Not to prevent oxidation, but to take advantage of the differing vapor pressures of different metals.

The boiling point in the standard tables that you’ll find are based on boiling at 1 atmosphere pressure.  Yet if you heat the metal under vacuum, you can get “boiling” points far lower, and at greater separations.  In fact you have to be careful when heat treating chromium containing alloys at above 1900F in vacuums of better than 10-4 torr, as you’ll lose metal from the surface of the alloys.  After a while, you can see the buildup in your vacuum furnace shielding and cold zones.  It’s really pretty neat, to see the science in action, and to realize THAT’S what the crumbly metal flakes are that are coating the fixtures in the furnace.

To answer the next, unstated question, it would be a VERY unusual occasion for this to be economical.  If I had a mixture of copper, zinc, and aluminum, it’d be far cheaper to throw it away and buy new metal than to separate it out by distillation.

And while it’s not technically distillation, zone refining is a commercially profitable analogue.  In that process you have a molten alloy, and you cool it s-l-o-w-l-y.  The first stuff to solidify is far purer than the average of the melt, containing the highest melting point element.

Answer 2

The process is feasible but not practical.

Zinc boils at 910°C, Aluminium at 2,467°C and, Copper at 2,567°C.

If you can find the boiling points at a high vacuum, these temperatures will be greatly reduced.

Careful control of the Vacuum (pressure) and Temperature in a Vacuum Distillation Unit, if it can withstand the low pressure),  would be a possibility. Taking off the lighter component (Zinc) as an overhead vapour, the Aluminium as a liquid Side-stream, and the Copper as the bottom liquid product.

The Zinc vapour will need to be cooled to its Condensing (boiling) point.

The Aluminium and Copper will come off at their boiling points and run into specially constructed 'lakes' to solidify and be 'mined' as pure metals.

The Zinc vapour will need to be cooled to its boiling point and treated in the same fashion.

(A very fanciful concept).

Answer 3

The 49ers used mercury to draw gold from crushed ore, then boiled off the mercury.  They condensed the mercury again by holding a cold skillet upside down over the process, and draining the mercury back into its container.

As has been pointed out, mercury fumes are dangerous.

Answer 4

The only pair I'm certain of is mercury from gold.This was used extensively in producing silver gilt.Lots of poor workers were badly injured by the process which involved dipping silverware into mercury which contained gold and then heating the workpiece to drive of the mecury and leave a coat of pure gold on top of the silver.The mercury fumes were vented in the open air.There is also in my memory a process whereby, in the blast furnace production of zinc, metals like cadmium, germanium and some others were collected in prolongs of the zinc condenser;the details are pretty hazy with me nowadays.I would add that native gold can be removed from crushed rock by mixing the rock dust with mercury,the mecury gold amalgam sinks to the bottom and after separation the amagam is heated to remove gold and the mercury is recirculated

Answer 5

Very few metals are volatile enough for this to be feasible. Mercury can be distilled (but the vapour is extremely poisonous).  The alkali metals can also be distilled, but only in an inert atmosphere. Zn and a very few other metals can also be distilled at temperatures that are easily reached.

Answer 6

Distillation is the process of purifying &/or separating into fractions a liquid by boiling it and condensing its vapors. So, if you are willing to boil metals to temperatures high enough to get them to melt than I think it would be possible.

Answer 7

no metals cant be seprated by this process

Answer 8

In theory it sounds possible, but operates at too high temperatures. And also nobody has ever bothered to find out though because its so much easier just to get metals from ore or by segregation in the melt (basically two metals not mixing). Usually you wouldn't need high temperature refractory ceramics.

Alloys are so complicated that metallurgists spend all their time dealing with getting the microstructure right that they don't have time for anything else.

Answer 9

some metals can be absorbed into fluids but not all so complete decomposition could be difficult to achieve. Especially if you wish to have the separate metals as metals .

Answer 10

I think you might be able to use fractional distillation, but i've only heard of that being used to seperate the components of crude oil.