One of the most important stations in the sugar house is the diffusion battery, and when that is in good working order, with everything moving smoothly, it can safely be said that the entire house is working all right. Starting the operations. — In starting the factory at the be ginning of the season, it is neces sary to fill eight or nine cells of the battery before making the first draw of juice that is to be sent to the first carbonatation station for treatment. When the proper number of diffusors have been filled, a certain num ber of hectoliters of the juice, containing sugar extracted from the beets, are measured off and sent to the first carbonatation station, for the purpose of clari fying and thus rendering the juice in a condition more easily to be treated for the process of boiling, when the sugar is se cured by crystallization from a highly concentrated syrup.
As the juice is drawn off and the cossettes be come more and more exhausted of their sugar con tent, it becomes necessary to replace them with fresh cassettes. This is done by shutting off the circulation in the cell to be refilled, emptying it by opening the door at the bottom of the cell, clos ing this door and refilling as at the beginning. This is continued at regular intervals in order that the process of diffusion may be continuous and that the best results may be secured. The beets remain in contact with the water at the temperature of 70° to 80° for one hour, when nearly the entire amount of the sugar has been extracted. The ex tracted cossettes are carried to the pulp pile and can be used to good advantage in the feeding of stock.
First carbonatation.—The first carbonatation sta tion consists of several tanks into which the juice is pumped and milk of lime added, having the den sity of 18° to 22° Bourne, the amount being figured at the rate of 3 per cent of dry lime to each ton of beets, and in terms of liters of juice. The addition of the lime to the diffusion juice is the most impor tant operation in the sugar mill, and experience 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.