336 • Marine Minerals: Exploring Our New Ocean Frontier 



ilmenite and rutile (both rutile and anatase "grades" 

 are manufactured). 



Titanium Slag: High titanium dioxide (Ti02) slag made 

 by electric furnace smelting of ilmenite with carbon, 

 wherein a large fraction of the iron oxide is reduced 

 to a saleable iron metal product. 



Titanium Sponge: The primary metal form of titanium 

 obtained by reduction of titanium tetrachloride va- 

 por with magnesium or sodium metal. It is called 

 sponge because of its appearance and high porosity. 



Transponder: A radio or radar device that upon receiv- 

 ing a designated signal emits a signal of its own. Used 

 for detection, identification, and location of objects, 

 as on the seafloor. 



Turbidity: cloudiness in water due to the presence of 

 suspended matter. 



Zooplankton: animal forms of plankton. 



