MOLASSES. 



in the form of cakes and the latter as grains. In both cases denaturated 

 alcohol (duty free) is used, the alcohol being recovered for use. Over 90 per 

 cent, of the sugar in the molasses is extracted at an average cost of 2s. for 

 every 100 Ibs. of molasses treated. 



The original substitution process of Steffen eliminates the use of alcohol 

 and is based on the behaviour on boiling of the mono- and bibasic lime 

 saccharates. The five operations in the process are : 



1 . Formation of a soluble bibasic saccharate in the cold. 



2. Transformation of the bibasic saccharate into sugar and insoluble 

 tribasic saccharate by boiling. 



3. Separation by filtration of the tribasic saccharate. 



4. Regeneration of the mother liquors by the addition of fresh molasses. 



5. Periodic reduction of the mother liquors. 



In outline the different processes are worked as follows : 



1. Molasses diluted to 11- 12 Balling are mixed with continual agitation 

 with powdered quicklime in the proportion of one part sugar to one of lime ; 

 the mixture is then filtered to remove scums. 



2. The filtrate is heated for ten minutes in autoclaves to a temperature of 

 105C. 



3. The tribasic saccharate formed in (2) is filtered, the cakes washed with 

 boiling water, and the saccharate employed in place of lime in treating the 

 raw juice. 



4. The mother liquors coming from (3) are used to dilute a further 

 quantity of molasses to a sugar content of 6 per cent. 



5. After a time the mother liquors are so charged with impurities as to 

 render them too impure to return ; they are then treated separately, two 

 operations sufficing to almost completely exhaust them. The mother liquors 

 are returned about 25-30 times, after which the process commences afresh. 



The cost of this process is only about Is. per 100 Ibs. of molasses, a 

 recovery of over 90 per cent, of the sugar in molasses being obtained. 



The second more recent process of Steffen considerably modifies and 

 simplifies the above process. 



It consists of three parts : 



1 . Preparation of a very pure finely divided quicklime. 



2. Formation of a tribasic saccharate insoluble in the cold. 



3. Extraction and purification of the saccharate. 



In preparing the quicklime, a very pure non-siliceous limestone is selected 

 which is burned out of contact with the fuel (see Chapter XI ) ; the burnt 

 lime is broken up in a stone-breaker and passed through a series of sieves to 

 obtain it in the necessary fine state of sub-division. 



399 



