"Vol. XII. No. 299. 



THE AGRICULTURAL NEWS 



325 



SUGAR INDUSTRY. 



CLARIFICATION OP CANii: JUICE BY 



ELECTRICITY. 



One of the latest and most interesting topics in the 

 sugar industry is the clarification of cane.juice by electricity. 

 The following table of figures which, it is claimed, show the 

 changes which the electrolytic process* induces, are taken 

 from the Louisiana Planier (August 9, 1913): — 



After 

 treatment, 

 Before the liquid 



treatment. decanted. 



1040 



10-76 



' 18-50 



17-89 



81-50 



96-70 



0'.328 



0031 



In the issue of the same journal for September 9, 1913, 

 E W. Ludwig discusses the criteria of the industrial possi- 

 bility of the idea. The greater portion of this discussion 

 devolves upon the results tabulated above, which, it is stated, 

 have little bearing on the practical question as to whether 

 the process can be made an industrial success. 



The criticisms of the writer referred to above on the 

 figures quoted, may be summarized as follows: — 



(1) Owing to the fact that the electric current induces 

 precipitations, combinations and the evolution of gases, the 

 first three lines of figures which deal with specific gravity 

 show nothing definite. 



(2) In the fourth line, the highei percentage of sucrose 

 shown, is inconclusive, because the process leads to a loss of 

 water by evaporation. The higher percentage of sucrose in 

 the juice after treatment is not necessarily proof of this loss 

 of water, because some of the soluble constituents of the 

 original juice have been precipitated. 



(3) The extraordinarily great increase in purity is 

 regarded with suspicion on general grounds. 



(4) The glucose percentages have no significance 

 because the sucrose figures are unreliable. 



(5) The accuracy of the ash determinations is 

 questioned because (a) they are very abnormal, (b) other 

 investigators have found that the electrolytic process increases 

 the ash percentage. 



(6) Changes in regard to acidity, of considerable 

 importance, are not given. 



I'ROrER TECHNICAL WAY TO AI'I'RO.VCH THE Snii.JEi;T. 



The article under consideration then gives a list of the 

 data required before the industrial feasibility of electrical 

 clarification can be established:—^ 



■* It may be explained for the beiiotit of the ijeneral reader 

 that the electrolytic process consists, in principle, in passing 

 an electric current through a liquid in which aie immersed two 

 metal plates each of which is attached, respectively, to the two 

 poles of a generating plant. The cur.eiit passing through the 

 liciuid from one pl.-ite (or electrode) to the othei-, sets up 

 chemical changes between the material composing the plates 

 and the liquid, or tlie substances dissolved in tlie liquid. — 

 LBd. A.N.} 



(1) Operating expenses: (a; i^viiMiuiiiii.ju of electrode 

 per litre of juice treated; (b) consumption of electricity 

 per litre of juice treated; (o) extra supervision and labour; 

 (d) price of electrode material. 



(2) Time taken to clarify a certain volume with aa 

 apparatus of specified .size. 



(3) Percentage loss (if any ) of sucrose in treatment. 



(4) Decrease in acidity of 10 c.c. of juice by treatment. 



(5) Increase of true purity. 



To avoid experimental errors, 20,000 gallons of juice 

 should be employed to obtain data (1), (a), (b), (2), (4), and 

 (5), which should all be determined on the same juice whose 

 purity should be stated. 



LOSS Of ELEirrROUE AND Or .SUI-.AR. 



In elaborating these points it may be added that the 

 question of the consumption of electrodes is an important 

 one. Only electrodes constructed of material that can 

 undergo chemical changes have proved practicable in the 

 process, although it is stated by Warren {Louisiana Planter, 

 August 9, 1913) that Murphy has invented a metal (?alloy) 

 which undergoes no appreciable loss, whilst answering satis- 

 factorily requirements as regards clarification. This Ludwig 

 describes as 'downright, unblushing alchemy.' 



Recognizing the fact that the electrodes must undergo 

 some change, it is, to continue the main point at issue, 

 important that they should be constructed of a metal which 

 is cheap and readily available in l.irge quantities. Aluminium 

 answers this purpose satisfactorily from a chemical aspect, 

 but the fact that the metal is in the hands of a few corpora- 

 tions who may at any time combine to force the price up; 

 has to be taken into careful consideration. 



Finally, in regard to determinations concerning loss of 

 sugar, it is essential to work first with artificial juice contain- 

 ing no sucrose, in order to pr'ive definitely that there is no 

 destruction of glucose. This information' would enable the 

 glucose ratio to be used as a reliable test for sucrose. The 

 only other way to determine the sucrose would be to obtain 

 the weight of sucrose present in a certain weight of the juice. 

 This would be a longer process, but more preferable. 



It has already been noted that acidity figures have not 

 yet been given. Ludwig believes that the question of acidity 

 will be found to be of great importance, and that even if the 

 electrolytic process is introduced, as it probably will be, the 

 employment of lime for neutralization purposes will never be 

 entirely dispensed with. 



THE WORLD'S CANE SUGAR INDUSTRY. 



Recently the above book has been reviewed in consider- 

 able detail by Q. Clarke, F.I.C., Agricultural Chemist to the 

 Government of the United Provinces, in the Agriculturat 

 .Journal of India (July 1913). 



The general conclusion arrived at is that the most 

 valuable and interesting information from ditlerent countries 

 is given, in the book, on the following points: (1) the price 

 of cane; (2) the out-turn of sugar per hundred cane; (3) the 

 yield of sugar per acre. 



It is shown in the article acknowledged above that the 

 price of cane in Cuba is not high in spite of the scarcity of 

 labour, owing to ratooning. In Hawaii, however, because of 

 labour difticultie.s, the pric is high, but is somewhat com- 

 pensated by a big out-turn of sugar. 



In conclusion it is suggested that it might be found 

 desirable in a new edition to present a little more informa- 

 tion in regard to the working of the central factory system. 

 in the West Indies, — information which would be welcoma-^ 

 to East Indian readeijs. 



