The extraction of Antimony from its ore

The following photographic documentation of the process of extracting antimony from its ore made by one of my French correspondents and one of his colleagues. He says:-
"These pictures describe an experiment undertaken a few years ago related to the Dry path of antimony (or Stibnite Path) as followed by E. Canseliet and, I guess (but opinions could differ on this point !) by Fulcanelli. The first group concerns the "liquation", i.e. the preliminary purification of the antimony ore (stibinite). The second series shows the Separation. Except for the ore which came from Bolivia, we worked with commercial products coming from a local chemical dealer."


Liquation

The purpose of this operation is to purify the crude ore from the main part of its coating. Although the operation could be made with two super-posed crucibles, as was described in several old treatises of chemistry, my friend chose to build a small "multi-purpose" furnace which could be used for other operations.

This picture shows this furnace. He made two similar plates of refractory concrete. Both of them have a circular hole for the exhausting of fumes or for the running of the melted ore. The top plate was fitted with handles made with electric wire.

The main chamber of the furnace was built with standard refractory bricks. My friend decided to avoid cement in order to change molten of broken brick without any difficulty. My opinion is it would be possible to simplify the building of this furnace with four "L" plates fitted at each corner.
The whole furnace is installed on two large breeze blocks in order to have a second chamber where a can of water (or another required liquid ) will receive the purified ore.
The furnace is heated by two gas burners fitted tangentially to the crucible. These burners are not expensive and are available from the Swedish firm SIEVERT (ref 2943): they are widely used for burning old paint or fusing road tar.
My friend used propane as a fuel. Butane is not convenient because it tends to freeze-up the gas bottle, regulator, gas pipe and stop-cocks when used with powerful burners. Charcoal could be also used but such a fuel is more difficult to regulate, regardless of the dust and smoke.
REMEMBER ! Take great care of your safety !!!

The crucible will be installed on a hollow cylinder of refractory concrete. My friend used the bottom of a plastic bottle as a mould for making this support.

The crude ore (reduced to pieces of about the size of a nut but not into powder) is placed in a crucible having a hole of 5 mm of diameter at its bottom.

A metallic wire-netting is placed around the crucible. Acting as a screen, it will "break" the flames coming from the two burners. Thus reduces the risks of breaking the crucible and the heat will be more even.

A cover is fitted on the crucible in order to reduce the oxidation of the sulphur.
REMEMBER ! : all parts of the furnace, crucibles and covers ought to be perfectly dry before being used. Refractory products are very fragile and expensive. Due to the fact they tend to act as a sponge, stock them in a dry place. A low temperature pre-heating will certainly be required.

The upper piece is now fitted. You should check that is it not too tight. Each part of the furnace needs room to expand under heat.

The two burners are now installed and lit. The gas flow should be moderate during the first ten minutes in order to avoid thermal shock.

A can of water (or another required liquid) is now placed into the lower chamber, just beside the bottom hole. When the temperature reaches the melting point of the sulphur the liquid will flow into the can. At this moment, it will be necessary to reduce the power of the burners in order to avoid oxidation and sublimation of the sulphur. Remember: Liquation is a kind of "distilation per descensum" and not a "sublimation" or a "calcination" .
You will stop the operation when noises tend to reduce in intensity. Don't try to obtain more from your ore : you'll waste your time.

The gas is now turned off. You have to wait until the temperature drops to normal before removing the top of the furnace in order to avoid thermal shock (crucibles are so fragile !) You'll see some yellow traces of sulphur on the walls of the furnace.
REMEMBER ! : BEWARE OF TOXIC FUMES !

The purified ore is now ready for further operations : Levigation (remember: "alcohol" means " "a very subtle powder" in Arabic. Good for your eyes !) , Assation, Separation .