Vol. IX. No. 225. 



THE AGRICULTURAL NEWS. 



387 



tluce the alkalinity necessary for the removal of the larger 

 proportion of the phosphates, there is always then an excess 

 of lime sufliciect to produce trouble in juices similar to that 

 under consideration, i.e., the formation of lime sulphate. 

 When sodium carbonate is ailded to -.i solution of the lime 

 sulphate, a double reaction takes place, calcium carbonate 

 and sodium sulphate resulting. When juice with lime in 

 excess for clarification, and a liigh content of sulphuric acid, 

 is treated with the sodium carbonate, the insoluble calcium 

 carbonate will settle out in the claritiers, only an unimportant 

 amount l)eing retained in solution in the juice. The sodium 

 sulphate, being very soluble, will continue through the course 

 of manufacture into the final molasses. Whilst the unnectss- 

 ary introduction of foreign soluble salts into the juice is 

 usually to be avoided, it is not thought that sodium sulphate 

 will have any serious effects. Koehler is quoted as finding 

 that ' certain salts, notably sulphate of soda, chloride of 

 calcium, and sulphate of magnesia, even possess the jiroperty 

 of causing the precipitation of a considerable proportion of 

 the sugar in solution in the liquid.' 



The use of sodium carbonate in addition to lime has 

 been advised, although not as a corrective for scale. 

 Geerligs writes: ' It happens in many cases that cane juice 

 has an acid reaction, although sufficient lime has been added 

 to precipitate all impurities. It is not advisable to evaporate 

 such acid juices, and they should therefore be neutralized, 

 which may be effected during ^defecation, or afterwards on 

 elimination of the settled juice. Until a few years ago, lime 

 was exclusively used for this neutralization, but as lime salts 

 always cause more trouble during the subsequent operations 

 than soda salts, soda has been adopted for this purpose. For 

 purifying purposes lime is, of course, the indispensable 

 agent.' 



Tlie resitilts obtained in the investigations Irad to 

 the following eonclnsinns: — 



Sodium carbonate clarification is indicated where a juice 

 contains excessive quantities of sulphuric acid, and tends 

 to form troublesome incrustations of calcium sulphate. 

 Lime should be added to neutrality or faint acidity, and 

 the juice made akaline Ijy sodium carbonate. This latter 

 reagent completes the precipitation of the phosphoric acid 

 and further, depending on the extent to which it is sui)plied, 

 removes calcic salts from the juice. The removal of these 

 salts lessens the extent of possible scale formation. It has 

 a further advantage, as much of the trouble found in the 

 working and handling of low grade products is ascribed to 

 the presence of lime, and the decomposition products of non- 

 sugars due to the action of lime at high temperatures. 

 Amongst others is the froth fermentation of molasses, which 

 is most frequently found where the juices have been over- 

 limed. Further, the increase in acidity of the molasses from 

 successive boilings is due to the decomposition of the lime 

 glucose compounds, lime glucinate, etc., at high temperatures. 



The addition of sodium carbonate will proliably increase 

 the work of the filter presses, but as it will produce a sedi- 

 ment, which by its nature should permit of easy and complete 

 washing of the scums, this objection may be only apparent. 

 The prime objection is the cost of clarification, which will be 

 materially increa.sed. Whether this increase of cost will be 

 more than compensated for by the saving in labour, wear and 

 delays due to incrustations on the tubes of the evaporators is 

 a questir n which can be answered only by trial in the mills 

 presented with this problem. 



The general conclusions may be summarized as follows : — 



The use of sodium carbonate in addition to lime in clari- 

 fying juices : — 



(1) Decreases the amount of insoluble ash in the filtered 

 juice. 



(2) Decreases the amount of phosphoric acid. 



(3) Decreases the amount of lime, 



(i) Increases the amount of mineral matter removed by 

 filtration, or the equivalent of the work of the filter pre.sses 

 in factory operations. 



(5) In juices of high sulphuric acid content, not enough 

 lime will be left to form a serious lime sulphate scale. 



(()) Effects a partial removal of magnesia from the juice. 



(7) Effects a slight increase in organic impurities remov- 

 ed from the juice. 



(8) Improves the working of after products by the 

 removal of calcium salts. 



(9) On account of the cost of the material, the expense 

 of clarification will be materially increased. 



CENTRAL SUGAR FACTORIES 



IN LOUISIANA. 



Though the number of active sugar houses in the State 

 has fallen off to a degree where the.se days it is getting to be 

 only the fittest that survive in the tight for life, the quantity 

 of cane disposed of at the lesser number of factories is in no 

 way reduced, and we see the situation in a much improved 

 light for the cane grower selling his crops. The planter who 

 runs his field as a feeder to mills owned by other parties is 

 finding that not only is he alile to command better prices for 

 his cane than formerly (when the more inefficient sugar houses 

 were unable to pay what the owners of the economically run 

 are able to do with cheaper cost of manufacture), but he also 

 finds that modern facilities for the removal of crops from 

 field to factory, and the rapidity with which the large mills 

 dispose of vast quantities of raw material, are benefits such 

 as the lack of in daj's past cost many a cane seller the loss 

 of portions of his crops in occasional bad harvesting seasons. 



To day, we see in Louisiana about fifty central factories 

 capable of grinding around 50,000 tons, or over, in a season 

 of sixty days or les.s, and some of these have facilities for 

 handling considerably over that amount. There are, in fact, 

 at least a dozen of these centrals equal to the disposing of 

 around 100,000 tons of cane in a .season, and about half that 

 number are scheduled to pass the mark this season, while of 

 the remainder upwards of twenty are due to go beyond 

 50,000 tons. Uanging below these are considerable numbers 

 which will grind from 30,000 to 40,000 tons, and through 

 the way aflairs are progresssing in the enlargement of equip- 

 ment in the Louisiana sugar houses, the better fitted and 

 bigger factories are soon to be even more decided in majority. 



The effect of having such manufacturing resources to 

 rely on has stimulated cane-growing efforts on the part of 

 numerous land-owners who would not have continued in the 

 business but for the advantage offered by the central factor- 

 ies. With the changes that were made in developing great 

 capacity plants from smaller ones, the cane grower was 

 encouraged by keener competition for his cane, and had the 

 advantage offered him of short hauls to place the cane on 

 either standard or narrow gauge railroad; the greatest advan- 

 tage, though, rests with the knowledge that the big mill is 

 ready to take his cane about as fast as he can get it off the 

 field, and taken altogether, it is olivious that the central 

 factory system as developed within the past two decades, and 

 increased to a larger extent within the past ten years, is the 

 very life and salvation of the Louisiana sugar industry, (The 

 Modern Sugar Planter, October 22, 1910.) 



