174 



NEW YORK STATE MUSEUM 



Alundum and carborundum 

 Alundum 



In 1902 the Norton EmeTy Wheel Co. of Worcester Mass., 

 established a plant at Niagara Falls for the production of arti- 

 ficial corundum from the mineral bauxite. This artificial product 

 is called " alundum " by the manufacturers, who have not as yet 

 made public the process of manufacture. 



From figures kindly furnished by the Norton Emery Wheel Co., 

 the following table showing the relative amounts of pure crystal- 

 line corundum in the natural ore and manufactured product, has 

 been prepared. 



AVERAGE ANALYSES OF CORUNDUM 



Best Turkish emery 

 ' ' Naxos emery . . 

 ' ' India emery . . . 



Alundum. 



A1203 



FesOs 



S1O2 



67.89% 

 69.13% 

 90.06% 

 97.99% 



26.72% 



25.46% 



4.25% 



1.50% 



5.37% 



2.57% 



5.17% 



.95% 



Loss 



2.19% 

 .77% 



At present the entire output of the factory at Niagara Falls is 

 consumed by the home company. It is expected by the manage- 

 ment that it will soon be in condition to place large quantities on 

 the market. Large demand for this product has already been 

 made, and it bids fair to prove a powerful competitor of car- 

 borundum. 



Carhorundum 

 Process of manufacture and refinement 



Carborundum is a carbid of silicon, in its crude state, a lustrous 

 irridescent mass of tabular hexagonal crystals. Its chemical 

 formula is CSi, and it closely approaches the diamond in hardness. 

 Absolutely pure carborundum is white. In commercial manufac- 

 ture the crystals are produced in many colors and shades, partly 

 as a result of impurities, and partly owing to surface oxidation. 

 The prevailing colors are green, black and blue. 



Sand, coke, sawdust and salt are the raw materials from which 

 carborundum is made. In early experiments clay was used instead 



