\ 



PHOSPHATES 75 



ped to Europe the remainder being used in this country. The 

 output of Tennessee phosphate has amounted to 5,315,422 tons 

 from 1893 to 1908. The Tennessee rock phosphates are not in 

 favor in Europe because of their high content of iron and alumina 

 oxides, which run from 2 to 4.5 per cent. 



The brown rock has been sold more than the blue or white 

 rock.* 



Canadian Apatite, — This is rock where the phosphate has be- 

 come crystalline and is known as apatite and is found principally 

 in the provinces of Ontario and Quebec. It is not mined very 

 extensively, only 748 tons being produced for 1907. It is a 

 variable product and contains impurities. The Canadian apatite 

 carries from 75 to 90 per cent, of tricalcium phosphate, which is 

 equivalent to 34 to 41 per cent, of phosphoric acid. Preparing 

 Canadian apatite for the market is a more expensive operation 

 than mining the American phosphates. Apatite is usually con- 

 sidered one of the purest forms of tricalcium phosphate for 

 manufacturing fertilizers.* 



Rodunda Phosphate. — This phosphate is found on the Rodunda 

 Island. It is not a phosphate of lime but a phosphate of iron 

 and alumina. Although the per cent, of phosphoric acid is high, 

 (20-38 per cent.) this material cannot be used to manufacture 

 into acid phosphate because of the absence of lime. The gypsum 

 (sulphate of lime) formed in the manufacture of acid phosphate 

 from phosphate of lime acts as a drier. Rodunda phosphate may 

 be used for crops provided it is well pulverized but it must be 

 considered as slow acting. This product is sometimes called 

 iron and alumina phosphate rock. 



Basic Slag. — This is known by several names as iron phosphate. 

 Thomas phosphate powder, odorless phosphate, and phosphate 

 slag. When phosphatic iron ores are used for the manufacture of 

 steel by the basic process, an excess of lime is used which unites 

 with the phosphoric acid and iron and forms a product known as 

 basic slag. There is not much of this product manufactured in 

 this country but the production is large in England, France and 

 Germany. According to Wiley: The quantity of basic slag 



