# Making elemental sulfur from pyrite FeS2

Has anyone done this or know of a good experiment that would allow someone to make elemental sulfur from $\ce{FeS2}$ (iron pyrite)?

• Please be aware that there's potential danger to liberate $\ce{H2S}$ which is highly toxic and at higher concetration has surprisingly pleasant smell. Also note that you can very quickly lose olfactory trace of it even though it is still present. I'm not trying to preach sermons here, but speaking from experience of a friend of mine who underestimate this danger and ended up in hospital severely intoxificated. – wuschi Oct 17 '15 at 18:14

## 1 Answer

You may just need to heat it.

$$\ce{FeS2 ->[\Delta] FeS + S}$$

In the wikipedia article of pyrite, it is written that:-

Thermal decomposition of pyrite into $\ce{FeS}$ (iron(II) sulfide) and elemental sulfur starts at 540 °C.

A good experiment for recovering sulfur from iron pyrite is called ' steam-pyrite interactions'. The following is an excerpt from the original journal:-

The reactions of natural iron pyrite with steam, hydrogen, and carbon monoxide have been studied in a fixed bed tubular reactor at 900-1 100°C. A new process has been developed for the recovery of elemental sulfur by the reaction of pyrite with steam. In this process, the yields of elemental sulfur and sulfur evolved as hydrogen sulfide and sulfur dioxide were, respectively, 84.5 and 13.7% of total sulfur under the following conditions: particle size, below 100 ASTM mesh; temperature, 1000°C; reaction period, 1 5 min; space velocity, 33.2 X lo4 cc/cc/hr; and partial pressure of steam, 1 atm. Under these conditions, the effluent gas also contained an appreciable amount of hydrogen. The calcine contained ferrous oxide, ferrosoferric oxide, silica, and 1.3% sulfur. The residual sulfur could be further brought down to a minimum of 0.2% in the calcine at 1 100°C using a 30-min reaction period. The incorporation of hydrogen in the steam-iron sulfides reactions at 1 100°C increased considerably the yield of hydrogen sulfide (59.5%), but only a small amount of metallic iron (1.6%) could be obtained.