Sugar-Making 265 



when enough sirup is thrown off to permit crumbling. 

 From the centrifugal machine the sugar is sent to the 

 driers, where any excess moisture is removed by a 

 current of warm air. The sugar is then ready to be 

 sacked and sent to the market. 



The sirup thrown from the centrifugal machines goes 

 to the second vacuum-pan, where it is further concen- 

 trated ; a second yield of sugar smaller than the first is 

 taken from it in the centrifugal machine. The molasses 

 is sometimes carried to tanks, where it is used in a manner 

 discussed in Chapter XII. If the factory is equipped with 

 the Steffen process, a third yield of sugar is secured. This 

 yield is small and represents only that part which would 

 remain as molasses or be partly saved, if the ordinary 

 processes are used instead of the Steffen. 



THE STEFFEN PROCESS 



Regarding this process Rolph 1 has the following to 

 say : " In some of the beet factories the sugar left in the 

 final molasses is extracted by what is known as the Steffen 

 process. The final low-purity molasses is diluted with 

 water and cooled to a very low temperature, after which 

 finely powdered lime is constantly added to the solution 

 at a uniform and slow rate. The sugar combines with the 

 lime and a saccharage of lime is formed which is insoluble 

 in the liquid. The suspended matter, or saccharate, is 

 then separated and washed in filter presses. 



"The cake from these filter presses, which is the sac- 



1 Rolph, G. M., "Something about Sugar" (1917), pp. 115- 

 116. 



