SUGAR-BEET 



SUGAR-BEET 



597 



has shown that unless it is added and the juice then 

 treated according to established rules, the final 

 yield of sugar is affected, both as to color and 

 amount. 



The effect of the lime on the raw juice is both 

 mechanical and chemical. Mechanically, it clears 

 the juice by causing those particles held in sus- 

 pension to settle with the precipitate. In the 

 chemical action, the lime has the power to decom- 

 pose the non- sugars, neutralizing the free acids 

 and acid salts, forming insoluble salts with the 

 oxalic and phosphoric acids present, as well as 

 many other compounds with the organic substances 

 present. By the carrying down of the impurities 

 with the lime a large number of bacteria and fer- 

 ments are separated and sink to the bottom of the 

 tank on standing, leaving the juice clear, of a light 

 amber color and perfectly sterilized, thus reducing 

 , the tendency of sugar inversion. 



The lime. — The lime required for 

 the purification of the juice is se- 

 cured from the purest' grade of 

 limestone. This stone is burned in 

 specially constructed kilns in the 

 presence of coke. The limestone is 

 composed of a lime - carbonate 

 which is broken up into lime and 

 the carbonic acid gas which is 

 used in the treatment of the juice 

 in the first and second carbonata- 

 tion. Impure limestone often 

 causes much trouble. 



While the operation of running 

 a lime kiln is simple in itself, there 

 are few persons who know how to 

 do it to produce the best results, 

 and it is important to dwell a little 

 on that point. In loading the kiln, 

 start at the bottom, using consid- 

 erable oily waste, some shavings, 

 small sticks, and the like, — enough 

 in one's judgment to start a good fire. Then work 

 up for some distance with gradually larger pieces 

 of wood, until just below the damper holes proper. 

 Beginning at that point, start loading again with 

 fine material, as below, arching over the space in 

 front of the holes, filling with more oily waste 

 directly in front of the holes. Then continue, as 

 below, gradually putting in heavier stuff and work- 

 ing in wood to a distance of six or seven feet above 

 the damper holes. Then loading about one foot of 

 pure coke on top. Above that, for a distance of five 

 to seven feet, loading with coke and rock, using 20 

 per cent coke to rock. Now fill the kiln about 

 three-fourths full with 105 per cent coke to rock. 



In touching off the kiln, always light the fires at 

 the damper holes, thus beginning at once to burn 

 the coke and the rock, and continue burning as the 

 wood burns downward. This has a twofold advan- 

 tage, as, should the fire go out for any reason, the 

 kiln can be lit again at the bottom. Never use 

 the gas-pump in starting the kiln, if it is possible 

 to avoid it, as the tar coming over causes a great 

 deal of trouble in the pump ; but use the draft 

 pipe in the top of the kiln for giving the draft 



until most of the wood has been burned, when the 

 pump can be put on to produce a forced draft. 



Always draw enough and only enough lime to 

 last the factory until about the time of the next 

 draw. In this way the lime will be drawn cold, 

 which is much to be preferred to the drawing of 

 the hot lime, as it will then be in the form of cold 

 ashes and be burned thoroughly. It is only in extra- 

 ordinary cases that more than 10 per cent coke 

 to rock is necessary, and more than that amount 

 is dangerous, as it often culminates in fuzing 

 the rock too much, and a consequent bridging of 

 the kiln. 



About half an hour before charging the kiln, the 

 kiln-boss should look in at the peek holes above the 

 top of the rock, and see whether the fire is coming 

 through. If so, half an hour afterward would be 

 the time for charging the kiln ; but, should the fire 



Fig. 824. Sugar-beet pulp at sugar factory. 



not have broken through, the time for charging 

 should be delayed until the fire shows. On the con- 

 trary, should the top of the rock be red hot, the kiln 

 should be charged at once. If, in looking into the 

 kiln, one side be found hot and the other dark, the 

 lower charging doors on the dark side should be 

 opened, while the others should be closed, thus 

 forcing the draft up through the dark side and 

 producing an even fire. 



The kiln should always be charged and run in 

 conjunction with the gas analysis. Should the gas 

 by analysis show a large percentage of oxygen, the 

 pumps should be allowed to slow down ; should the 

 analysis show a large quantity of carbonic oxid, 

 the pumps should be speeded up. In drawing in this 

 way, — that is, drawing simply enough lime to keep 

 the house running,— one will find that the amount 

 of gas will always take care of itself. 



A rock having over one per cent of magnesium 

 should be carefully watched, as it causes great 

 trouble in the juices ; and a rock containing a large 

 percentage of silica should be avoided, as it fluxes 

 and helps to bridge in the kiln. A rock of 96 per 

 cent carbonates, as a rule, is considered excellent. 



