Sulpher

Sulphur – Only in hell you say? Pity
© Bert Ellison  1999 - 2002

Well, if Hell be "down there", there certainly is lots of it, mostly in the earth’s core, combined with metals as iron and nickel. It is less common in the crust – the outer skin – but has a presence of 260 ppm (parts per million). Seawater has 870 ppm and the human body contains 2000 ppm. Sulphur is chemically versatile and combines with many other elements in sulphides, such as pyrite (FeS2), as sulphates like celestite (SrSO4) and in the uncombined element (S).

As brimstone, the fiery fate of evildoers, sulphur is mentioned at least six times in the bible.

We are quite familiar with the bright yellow color and the common orthorhombic crystals. It is soft at H2 and very light, SG about 2. It ignites easily – one reason it’s used in matches – and burns with a blue flame, giving off very pungent fumes.

Elements which combine with sulphur are chalcophiles (sulphur loving) and many useful elements – iron, nickel, copper, lead etc. are tied up with it. And we are all familiar with the results of tearing these compounds apart -–sulphur dioxide – which combines with moisture in the air to yield acid rain.

So depending on how we treat it, sulphur is a blessing or a curse. When tamed, most of it goes into making sulphuric acid, one of the most important industrial chemicals.

Hydrogen sulfide gas (H2S) is lethal at concentrations as low as .08 percent, is very corrosive to metals and doesn’t endear itself with its "rotten egg" odor. Oddly this stink of sulphur in mercaptans is used to save us from leaky gas lines and propane – it’s added to our fuel to warn of leaks.

Sulphur in H2S gas is a devil for the petroleum industry. Crude oil almost always has some S – after all petroleum comes from organisms – from about 2% by weight to common 5%. One deep well known to this writer in the Alberta foothills came in with 90% H2S – so much that as the gas reached the surface and expanded, raw sulphur soon plugged the well shut.

Hydrogen sulphide, therefore, must be removed before natural gas can be used and it is, in vast amounts. There are over twenty gas plants in western Canada each removing sulphur; seeing has to be believing. Visualize a block of sulphur one city block (or more) wide by two city blocks long (or more) and perhaps 10 storeys high at many plants and one can readily see why Alberta is the world’s greatest producer of sulphur from natural gas.

The United States is the greatest producer of sulphur, in this case from buried salt domes where it accumulates in the cap-rock. Hot water is pumped down one pipe to dissolve the sulphur, and returned up another, the Frasch process.

Much is also produced by volcanoes and in the smelting of sulphide ores. There are also huge amounts tied up in sedimentary rocks like gypsum (CaSO4.2H2O) and anhydrite (CaSO4).

And don’t forget gunpowder, fireworks, paper, rubber, insecticides and medicines. Sulphur has its good sides too.

 

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