The Phosphates of America. 125 



endless chain. Each bucket holds a known weight of material and 

 -each empties itself into the hopper of the mixer. Where there is 

 no convenience for establishing an endless chain, the material can 

 be carried to the hopper in sacks direct from the mill. When 

 this hopper contains 1000 pounds of the powder, the acid tap 

 underneath it is turned on, the agitators of the mixer are set in 

 motion, arid then the powder is allowed to run in a steady stream 

 from the hopper. 



When all the acid and the phosphate are in the mixer, the 

 agitators are made to revolve with swiftness and energy for about 

 two minutes, after which the trap of the mixer is opened and its 



SUPERPHOSPHATE MIXER. 



contents, a thick mud or mortar-like mass, are shot from it into 

 one of the " dens " at its either extremity. 



These operations are repeated until the "den" is full, care 

 being taken to keep the gas-flues open and to see that the acid 

 always runs into the mixer in advance of the powder. A neglect 

 of the latter precaution invariably results in serious difficulties 

 from clogging. 



Each charge should be equal to an average of about 1900 

 pounds, and each "den" should hold about 120 tons. Assuming, 

 therefore, the length of time required for running a charge to be 

 five minutes, it is an easy matter to fill up a " den " each day of ten 

 working hours. 



-The mixed mass enters the " dens " in a semi-liquid state and 



