SULPHUR AND PYRITE 359 



nearly trebled by the French firm who had purchased from the 

 Sicilian government the monoply of the sulphur exportation 

 from that island, that the use of pyrite by acid makers attained 

 any importance. In the United States, which leads the world 

 in the consimiption of sulphur, this substitution of pyrite for 

 sulphur in acid making has continued steadily during the past 

 twenty five years, and owing to its cheapness and widespread 

 occurrence, pyrite has almost completly replaced the crude 

 sulphur that was formerly used almost exclusively. This 

 change in acid making has resulted largely from the treatment 

 of phosphate rock by sulphuric acid, by which it is made into 

 valuable fertilizer, and also from the use of the acid in the re- 

 fining of crude petroleum. For these purposes the use of a 

 high grade, pure sulphuric acid is not essential. Unrefined 

 sulphuric acid made from pyrite is generally contaminated 

 with arsenic, and frequently with the additional impurities, 

 copper, zinc, and selenium, but not in sufficient quantities to 

 bar its use in preparing fertilizers or in refining the crude petro- 

 leum. The impuritieS; too, may be removed if desired, and a 

 pure acid produced. 



To give some idea of the large quantities of the acid con- 

 sumed in these industries, it may be stated that 1 pound of acid 

 of chamber strength is required to convert each pound of crude 

 phosphate rock into acid phosphate or commercial fertilizer, 

 and in one year 1,500,000 long tons of the crude phosphate rock 

 w^ere mined. In refining crude petroleum each gallon of com- 

 mercial petroleum (kerosene) requires 1 pound of sulphuric 

 acid of a strength of 66° B. for its production, and during 1902 

 the output of crude petroleum in the United States amounted 

 to over 89,000,000 barrels, each of 42 gallons capacity. In 

 estimating the quantity of acid consumed in these two industries 

 alone, any calculation based upon figures of production, less 

 imports, both of crude petroleum and phosphate rock, must 

 necessarily be tentative and not even closely approximate, 

 for the reason that it is impracticable to ascertain the exact 

 quantities of stock of crude material on hand at the beginning 

 and at the close of a year. For practical purposes, however, 

 it may be assumed that the consumption of sulphuric acid in 

 the United States at the present time is approximately in the 



