Carbonation.— The purification of the sugar solution as above extracted consists of the ap plication of lime, carbon dioxide and sulphur, together with settling and filtering. The use of the lime followed by that of carbon dioxide is termed carbonation. These two materials, lime and carbon dioxide, are obtained by burning limestone in a kiln constructed for that pur pose at the factory. The limestone is decom posed and the lime, mixed with water, is added to the sugar solution in a quantity equal to 2 or 3 percent. The gas is led from the lime kiln through water to wash it and admitted into a large cell from five to six feet in diameter, with a capacity of from 4,000 to 6,000 gallons. These cells are provided with steam coils so the solution may be heated. The temperature at which the carbonation is carried on is 80° to 90° C. This process of adding lime, then charging with carbonic acid gas, is repeated two or three times, depending upon the quality of the juice, but after the first treatment the juice is filtered each time before repeating the carbonation. Finally the juice is treated with sulphur dioxide, which is used to bleach the solution, and then the excess of this gas or acid is removed by the addition of lime and the juice is again treated with carbonic acid. Be fore filtering the juice it is allowed to settle so that the impurities may collect at the bottom of the settling tank. The clear liquid is drawn off and filtered by gravity through bags. These bags are arranged in pairs, a large bag with a diameter of three or four feet is partially folded and put into one of thicker and stronger material, with a diameter of not more than 12 to 18 inches. When the bags become filled with impurities they are steamed and washed and made ready for another operation. That por tion of the solution containing the bulk of im purities is also filtered through bags which are i placed in a filter press and much of the liquid removed. The press cake is scattered over the field and used as a fertilizer. The clarified juice is treated the same as under cane sugar.
Molasses.-- The molasses, containing 40 to 50 per cent of sugar, discharged by the centri fugal, must be treated for the sugar which it contains, though some of it in Louisiana is sold to merchants for direct consumption as table molasses, to confectioners and to glucose mixers for the preparation of glucose syrup. Generally, this molasses is recooked over and over again until all of the crystallizable sugar has been separated. The first reboiling yields "second sugar" and 'second molasses," the second reboiling "'third sugar" and molasses," etc. The reboiling may be done directly in the vacuum pan without previous treatment, in which case 5 to 10 per cent of water is evaporated, the boiled mass put into hot-room cars and kept at a temperature suffi cient to maintain the masse cuite in rather loose or limpid state for from one to three weeks, or put into large cylindrical, slowly revolving drums provided with a proper supply of heat and kept in these for three to four days trOpermit crystal lization to take place in motion. in either case i the masse cuite is returned to,tit „ centrifugal and the crystals separated frbit ,molasses. The practice at some factories—is, 'mix the t Molasses with hot juice before rebo while others put it into glithinating pans, ' rge it with steam, dilute and redianfi. Th econd sugar may be sold to the refineries, but as it falls below the 96-test sugar (probably the most profitable grade) it is melted in the hot juice and turned out as first sugar of the test above mentioned. The second molasses is re
boiled to "string proof," put into large magma tanks or hot-room cars (about five by five feet and three to four feet deep) and allowed to remain at rest from four to six months, when the crystallized mass is subjected to centrifugal ing. The third molasses usually contains a large portion of impurities which may make it unprofitable to further reboil it, though some work this molasses for fourth sugar. All the above grades of sugar recovered by reboiling may be worked back into a first sugar or sold to the refineries. The refuse or exhausted molasses, which amounts to from four to five gallons per ton of cane crushed and carries 25 to 40 per cent sugar, has increased very much in value in recent years, selling at 6 to 10 cents per gallon. Some of it is fed to stock and some consumed by distillers.
The molasses from the beet is worked over again and finally, in some factories, diluted, treated with powdered quicklime, which forms a sucrate of lime at low temperatures, and this sucrate is decomposed, with carbon dioxide, filtered and evaporated to obtain sugar. The final disposition of the beet molasses is also unprofitable.
Refining.— The refining of sugar consists in washing, melting, purifying, evaporating and recrystallizing. Some factories in Louisiana turn out two or three grades of refined sugar or sugar that is sold direct to the trades, but as the process used by them for refining con sists chiefly in washing with water, with a solution of tin chloride, ultramarine or phos phoric acid, it is expensive because of the large portion of the sugar that is dissolved while washing in the centrifugal machine. "White clarified,z' °yellow clarified" and granulated sugars are the grades referred to, but the amount of these turned out is decreasing every year. The chief difference between refining and manufacturing of sugar is in the method of clarification. This is similar in almost every respect, except in the refinery, the sugar solu tion, after melting and chemical treatment and filtering, is filtered through ebone black') or bone charcoal. This substance has the property of decolorizing the sugar solution which leaves these filters in an almost colorless condition.
The evannratinn and crwctallizatinn are carried 5 to 25 years. The sugar season is from No vember to February. The sugar is obtained by tapping the tree. The tapping consists in mak ing a triangular hole in the tree, into which the sap is collected. The sap is withdrawn from the tree by means of a spile in a hole bored beneath and inclined upward to the sap recep tacle. Through this spile the sap runs out and is collected in earthenware vessels. The spile is generally made of bamboo cane. The flow of sap is more rapid at night than in the day and the curler the night the oreater the limn A out in the same way as in manufacturing. The bone charcoal soon loses its power to decolorize and is then revivified by burning out the absorbed material in specially constructed re torts. The bone black will finally be exhausted of its valuable property of decolorizing and it is then sold to the fertilizer manufacturer for the manufacture of acid phosphates. The refuse molasses is used for making alcohol, for cul inary purposes and to some extent for making lampblack and shoe polish.