Man's physical universe

xanabras

OXYGEN AND SULFUR, CARBON AND SILICON 625

crust. It is an essential element in the molecules of some proteins.

Sulfur occurs in large quantities in the form of sulfides of iron, copper,

zinc, and lead and sulfates of calcium and magnesium. It is estimated

that the oceans contain eleven hundred trillion tons of dissolved sulfates.

In the uncombined state sulfur occurs in the vicinities of hot

springs and volcanoes, where it was probably deposited by the interaction

of the sulfurous gases of these regions as follows:

2H2S + SO2 —>- 2H2O + 2S

hydrogen sulfide sulfur dioxide water sulfur

or by the decomposition or oxidation of the hydrogen sulfide formed

from underground deposits of metallic sulfides by still different reactions.

Large sedimentary beds of sulfur, which are always closely associated

with gypsum and limestone, are thought to have been formed by the

action of carbon compounds on gypsum, CaS04, to form limestone,

CaCOs, and sulfur. Over 95 per cent of the world's production of

sulfur comes from these sedimentary deposits, the most important of

which occur in Sicily and the Gulf Coast of the United States.

It is estimated that over 30,000,000 tons of sulfur have been mined

in Sicily, which supplied the world with sulfur for five hundred years.

Today the Sicilian deposits account for only 12 per cent of the world's

production of sulfur because Herman Frasch devised an economical

process to obtain sulfur from the world's largest sulfur deposits in the

Gulf States, which occur in beds lying from 500 to 1500 feet below the

surface. Shaft mining failed here because of the nature of the ground

and the presence of the poisonous gas, hydrogen sulfide.

In 1891 Herman Frasch patented his process to remove sulfur from

these deposits by forcing superheated water into the sulfur beds to melt

the sulfur, which is then raised to the surface by compressed air.

Since 1903, when the Frasch process was finally perfected, 45,000,000

tons of sulfur have been produced in the United States.

This economical process produces sulfur of a purity of 99.5 per cent,

which can be stored in the open without loss.

Sulfur Is One of the Five Basic Raw Materials of Chemical Industry.

Salt, coal, limestone, sulfur, and water have long been considered to

be the five basic raw materials of chemical industry. Eight per cent

of the sulfur mined is burned with air to produce sulfur dioxide, which

is used extensively for producing wood pulp, for bleaching, for the

treatment of fruits to prevent oxidation and bacterial action, as a

refrigerant, and for the preparation of sulfuric acid.

In the preparation of sulfuric acid, sulfur dioxide must be changed

More magazines by this user
Similar magazines