CHAPTER XIII 

 OTHER FORMS OF LIME 



Air-Slaked Lime. A pure limestone is a 

 carbonate, and the chemical formula is 

 CaCOs. When it is burned, the carbon 

 dioxide (CO2) is driven off, leaving CaO, 

 which is calcium oxide, called fresh burned 

 lime. In this process 44 pounds of a stone 

 weighing TOO pounds passes into the air, 

 and there remain 56 pounds of lime. 

 When it air-slakes, it takes back the carbon 

 dioxide from the air, and the new product 

 becomes CaCOs, or carbonate of lime, and 

 regains its original weight of 100 pounds. 

 This is what would happen if the process 

 were complete, and it is nearly so when the 

 exposure to the air is as perfect as possible. 



Fifty-six pounds of valuable material are 

 in the 100 pounds of air-slaked lime, just as 

 is the case with limestone, and there is no 

 difference in effectiveness except in so far as 

 the air-slaked material is absolutely fine and 

 available, while most pulverized limestone 

 is less so. In making purchase for use of 

 land the buyer cannot afford to make any 



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