SULPHUR AND PYRITE 357 



utilization for the maniifaoture of pip; iron, thoro would n*sult 

 an annual saving of nuiny thousand tons from what is now a 

 waste product. As yet, howevor, the recovery of sult)hur and 

 iron from these ores is in an experimental state. 



Other experiments have recently l^een conducted for the 

 utilization of the l)y-product f^jases resulting from the roasting 

 of zinc l)lende ores, the practicability of which has been demon- 

 strated with financial profit at the zinc plants of Peru and 

 Lasalle, in Illinois, and of vVrgentine, in Kansas. It is feasil)le 

 to save from 25 to 28 per cent of the sulphur content of the 

 zinc ores during the roasting, which yields a product containing 

 not more than 2 per cent of sulphur. By subsequently roasting 

 this product — cinders, as it is called — in the Chase or other 

 t}^e of special roasting furnace, the remainder of the sulphur 

 will be expelled, and the dead roasted zinc ore will then ])e in 

 proper condition to permit of the extraction of the zinc at very 

 low cost. There is an immense supply of sulphur in the zinc- 

 iferous sidphide ores of Arkansas, Colorado, Kansas, Kentucky, 

 Missouri, and other states, and it is well within the range of 

 probabilit}^ that ere long the tonnage of sul})hur derived from 

 pyritiferous ores will l)e largely augmented by the utiHzation 

 of the suli)hur contained in these zinc sulphide ores. 



An important factor in the development of the pyrite 

 industry is the demand for sulphuric acid in the treatment of 

 phosphate rock, and in the refining of petroleum. Since a 

 chemically pure sulphuric acid is not essential for these pur- 

 poses, the acid made from pyrites serves quite as well as that 

 made from sulphur. Another field for the future extension of 

 the utilization of the pyiitiferous ores lies in the making of 

 sulphur dioxide gas for use in bleaching wood pulp, which is 

 the basis of the manufacture of paper by the sulphite process. 

 Heretofore American manufacturers of paper using this pro- 

 cess, with one or two exceptions, have been limited to the use 

 of sulphur for making sulphur dioxide gas, although in Europe 

 a considerable quantity of pyrite has been thus utilized. It is 

 quite probable that the difficulites that have heretofore existed 

 in the way of utilizing pyrite in the bleaching of pulp will be 

 overcome in the near future. When this becomes an ac- 

 complislied fact it will open up a large field for the consumption 



