Cold extraction of mercury with copper

For an introduction to the recipes that have been replicated, see the section on Cold Extraction of Mercury: Sources

Greek recipe

Theophrastus, On Stones, chap. 60

Mercury is produced by grinding cinnabar with vinegar in a copper mortar with a copper pestle.

ποιεῖται (scil. χυτὸν ἄργυρον) δὲ ὃταν <κιννάβαρι> τριφῇ μετ’ ὂξους ἐν ἀγγείῳ χαλκῷ καὶ δοίδυκι χαλκῷ.

Syriac recipe

Zosimus of Panopolis (Syriac tradition), Ninth treatise on the letter ṭet. The letter ṭet includes the full discourse that speaks about the work of mercury

Another (recipe). Take copper scrapings and grind (cinnabar) with water. Little by little you will collect the mercury (lit. cloud) that floats on the surface with a sponge, until all (the ingredients) have been exhausted and consumed. Then put (what is left) in a vessel without a lid; you will cover it with another vessel and place this vessel on a fire of sawdust. You will find mercury in the upper (vessel).

ܣܝܪ. ܣܒ ܫܘܦܐ ܕܒܠܬ<ܝ>. ܘܫܚܘܩ ܒܡܝ̈ܐ. ܒܐܝܕܐ ܒܐܝܕܐ ܗܘܝܬ ܫ̇ܩܠ ܥܢܢܐ. ܗܝ ܕܛܝܦܐ ܡܢ ܠܥܠ ܒܐܣܦܘܓܐ ܥܕܡܐ ܕܟܠܗ ܡܬܛܠܩ ܘܝܒܫ. ܘܐܪܡܝܗܝ ܒܙܒܘܪܐ ܕܠܝܬ ܠܗ ܟܣܝܐ. ܘܟܣܝܗ̇ ܒܐܚܪܬܐ. ܘܣܝܡ ܥܠ ܢܘܪܐ ܕܢܣܪܬܐ. ܘܡܫܟܚ ܐܢܬ ܠܥܠ ܐܝܟ ܥܢܢܐ

Replicating the procedure

 

Modern chemists immediately recognize copper—that is, the metal from which pestles and mortars are made—as a key reagent. We ground mineral cinnabar in a mortar along with copper powder. While grinding, the powder gradually turns black (chalcocite, Cu2S) and, after several hours, we obtained some clear droplets of mercury.

The vinegar mentioned in the sources actually catalizes the reaction: HgS + 2Cu → Cu2S + Hg.

Cinnabar (Hg) and copper powder in a ceramic mortar
Fig. 1. Cinnabar (Hg) and copper powder in a ceramic mortar
Grinding of cinnabar, copper powder and vinegar in a ceramic mortar
Fig. 2. Grinding of cinnabar, copper powder and vinegar in a ceramic mortar
Droplets of mercury after grinding
Fig. 3. Droplets of mercury after grinding

In order to reach a complete reaction -and frankly, make it less exhausting- we used a ball mill to grind the ingredients.

Ball mill used to grind the ingredients more efficently
Fig. 4. Ball mill used to grind the ingredients more efficently