2l8 DAIRY TECHNOLOGY 



dred pounds. The largest factory of this kind in the 

 world is located in Illinois and has a capacity of one and 

 a half tons of milk sugar per day. They get on an average 

 3.4 pounds of sugar from 100 pounds of whey. At this 

 factory the whey from casein making as well as the whey 

 from cheese factories is used, the sugar from the former 

 source being of just as high quality as that from the latter. 



The Process of Manufacture. Whey, acidified to 

 about one per cent of hydrochloric acid, is heated in large 

 vats to the boiling-point with steam. This precipitates 

 the albumen. The solution is then made neutral with 

 calcium hydroxide, evaporated in a vacuum pan to a 

 syrupy consistency (22 to 25 Baume), and filtered 

 through a series of cloths in a high-pressure filter press. 

 When sufficient syrup has accumulated, it is again run 

 into the vacuum pan and evaporated, at about noF., 

 to a much richer syrup. This latter is drawn out into 

 shallow boxes, where it cools and crystallizes, in 24 to 48 

 hours, into what appears to be a yellow sand. This is 

 crude sugar, and must be passed through several proc- 

 esses of purification. 



This mass is first washed with cold water in a centrifuge. 

 The centrifuge is a combination of drums with perforated 

 walls and fine sieves. The syrup is thrown out through 

 the sieves and the sugar crystals are retained within 

 them. The crystals are here washed with cold water 

 to remove calcium chloride and other soluble impurities. 

 The washings and the syrup thrown out by the centri- 

 fuge are saved and the contained sugar recovered. The 

 sugar crystals are redissolved in hot water, certain chem- 

 icals are added and the solution is allowed to stand over 

 night. In the morning the clear liquid is siphoned off. 

 The settlings in the bottom of the tank are filtered and 



