THE CLARIFICATION OR DEFECATION OF THE JUICE. 



, 2. Phosphoric acid and soluble phosphates and acid phosphates of the 

 alkalies and alkaline earths and of aluminium. 



3. Salts of aluminium in combination with bodies designed to produce a 

 precipitate of alumina, and including the aluminates of the alkalies and of the 

 alkaline earths ; the precipitation of alumina within a sugar solution whether 

 from an alum or aluminate produces a notable clearing of the solution and the 

 carrying down of much colloid matter, but the writer is of the opinion that 

 the value of the amount of material required is greater than the benefit to be 

 obtained, in addition to the difficulty of handling the very bulky gelatinous 

 precipitate formed. 



4. Salts of the heavy metals, especially of lead, zinc and tin. All of 

 these produce copious precipitates, but their poisonous nature is an insuperable 

 obstacle to their use. 



5. Baryta and its salts, and in combination with other agents. Baryta is 

 certainly a powerful clarifying agent, but its poisonous nature, as well as the 

 expense involved, prevents its use. 



6. Agents designed to the removal of potash, including the use of 

 fluosilicic acid and its salts, and filtration through layers of calcium aluminium 

 silicates. 



7. Unclassified agents, including ozone, chlorine,, hypochlorous acid, 

 hydrofluoric acid, permanganate of potash, chromic acid, tannic acid often 

 suggested to be used in combination with aluminum salts, oxalic acid in com- 

 bination with lime, clay, brick dust, oils, kieselguhr, albumen. 



8. Electrical processes. 



Of later processes that have been proposed may be cited those of Hanson 7 , 

 which include the use of zinc, tin, hydrosulphurous acid, hydrogen peroxide, 

 and aims at a decoloration of the juice and direct manufacture of white sugar 

 by alternate oxidations and reductions. Gans 8 proposes the use of artificial 

 zeolites or calcium aluminium silicates as a filtering material, whereby the 

 potash of the juices is replaced by lime ; this material was placed on the 

 market under the name of ' Permutit,' but Claassen 9 , who examined its action, 

 found that, although the potash could be thus removed, the viscosity of the 

 resulting material due to the substituted lime salts was much increased, and 

 he was unable to recommend its use. Hlavati 10 proposes the removal of 

 potash by means of fluosilicic acid, and Besson 11 employs powdered aluminium 

 alloys in an alkaline juice to obtain a precipitation of alumina and decoloration 

 through the agency of the hydrogen evolved. When this plan is used in the 

 juice in the evaporation, a diminution of the deposit of scale and an increased 

 transmission of heat is claimed. 



A detailed list of the various proposals has been given by von 

 Lippmann 12 . 



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