Preparation

Sulfur

1. The Frash method (from the minerals of free sulfur) is based on the sulfur fusibleness and its relatively low specific density. Overheated water steam (at 170⁰) and compressed air is pumped on pipes under earth (see figure below). Molten sulfur forms foam and is darted out on a surface. So elemental sulfur is obtained with a purity up to 99,5%, which is suitable for the direct use.

The Frasch process

2. Klaus method (from industrial and natural gases which contain H₂S and SO₂):

SO₂ + 2H₂S = 2H₂O + 3S (a catalyst is traces of water)

3. Decomposition of pyrite:

FeS₂ FeS + S (without access of air)

(reaction of selfoxidation-selfreduction, or disproportionation):

Industrial uses of sulfur

Selenium, Tellurium, Polonium

In industry. Se and Te can be isolated from wastes of copper, iron, and lead processing where selenium and tellurium are by-products:

- at FeS₂ oxidising annealing next to SO₂ having special applications SеO₂ and ТеO₂ are also formed. They are separated, concentrated, and then reduced by SO₂ in concentrated HCl to elemental chalcogens:

EO₂ + SO₂ + H₂O = E + 2H₂SO₄.

Sеlenium is separated at first and Tе can be isolated after the strong dilution of a solution (the content of tellurides in sulfide ores is considerably lower than selenides).

- at electrorefining of metallurgical copper from anode slime(mud) in considerable amounts.

content of the method: metallurgical copper is used as a soluble anode, copper of high purity (99,9% Cu) is formed during the cathode process on a cathode. Se and Te pass to anode slime that is accumulated on the bottom of electrolysis bath and serve as a raw material for production of elemental chalcogens Se and Te (oxidation of raw material to ЕO₂ and its subsequent reduction by SO₂).

Polonium (²¹⁰Ро) is produced (in kilogram amounts) in atomic reactors at bombardment of bismuth (²⁰⁹Ві) by neutrons:

²⁰⁹Ві (n, ) ²¹⁰Ві ²¹⁰Po

and also from wastes of uranium ores processing.

1 interplace between one another переплітаються між собою

2 to boil down — випарювати

3 ca – abbreviation meaning circa (приблизно)

4 ppm — abbreviation parts per million

5 селенових випрямлячів