US1486091A - Process for defecating sugar juice - Google Patents

Description

Patented Mar. d, 192%.

mam

WILLIAM DODGE HORNE, OF YONKERS, NEW YORK.

PROCESS FDR DEFECATING SUGAR JUICE.

fi o Drawing.

To all whom it may concern:

Be it known that 1, WILLIAM Dooon HORNE, a citizen of the United States, and a resident of the city of Yonkers county of S \Vestchester, and State of New York, have invented a new and Improved Process for Defecating Sugar Juice, lowing is a full, clear, and exact description.

This invention relates to a process for the w defecating of sugar juice and hasreference more particularly to a process of the class described, in which the sugar juice is first treated with lime to strong alkalinity. to litmus and after the removal of the precipi- 1 tate formed, a precipitant such as sodium phosphate is added to precipitate the excess of lime. v

Acomplete precipitation .of the precipitable impurities in cane. juice can only 29 attained by adding lime considerably beyond the point of a slight alkalinity to lit-. mus, but it is not always'necessa'ry to add lime to the point of alkalinity to phenolphthalein. The exact amount'may be de- $5 termined by experiment by testing the filtrate from any particular lime addition with more lime andheating to see if a vfurther precipitate is thrown down. In the case of burnt, fermented or unusually acid sugar so juice, soda, such as the hydroxide, carbonate or bicarbonate of sodium, may be added to make the precipitation more com lete. Only a moderate heat, 105450 degrees is necessary to complete the precipitation. e-

ficiency' of lime cannot be made up for by excessive heating. The practice heretofore has been to heat the sugar solution to 200 F. or over, after adding a quantity of lime which would not destroy the invert sugar at 40 the high temperature. owever, this quantity is insuflicient to precipitate all the impurities in the sugar solution. In any event the solution must be strongly alkaline to I litmus to insure the insolubility of the precipitate formed;

Any appreciable amount of lime leftin a sugar solution is very detrimental, as in the heatin of thet solution to evaporate and crystal ize, the lime combines chemically 5a with the reducing sugars, forming darkcol-v of which the fol- Application flied November 13,1919. Serial No. 387,823.

ored bodies which cannot be removed by crystallization, but remain in solution and prevent thecrystallization of sugar. Therefore in any satisfactory method of defecation some means must be provided for removing that portion of the added lime whichis not precipitated by the acids, gummy substances, nitrogenous bodies, etc.,' in the raw juice. If the excess of lime over that existing .in the precipitate be neutralized with phosphoric acid alone or a phosphate acid to litmus in the presence of the precipitate, the precipitate will immediately redissolve in large part, allowing the once separated impurities again-t0 enter into solution and so defeat'the object of. the defecation.)

The object ofthis invention therefore is to filter, settle out, or float off the precipitated impurities, resulting from the addiof large amounts tion of lime, from the clarified juice, and

then to remove the excess of lime so as to prevent the subsequent destruction of reduc:

ing sugars, formation of dark colored melassigenic substances, formation oi lime scales on the heating tubes and surfaces of the heating appliances, slow boiling, cloudy residual molasses, and a strong disagreeable taste in the-final sugar products.

The removal of the excess of lime is best accomplished by the addition of sufficient suitable lime precipitant, such as a soluble phosphate, carbonate, bicarbonate, sulphite, isulphite, oxalate, 'etc., preferably neutral or slightly alkaline to litmus, at a tempera-- ture of 175 F. or above. Phosphoric acid alone .or a is not suita le for this purpose. as such rea ent is far from thorough in its removal 0 lime. However, said phosphoric acid or acid phosphate may be mixed with the proper proportion of theoxide, hydrate, carbonate, and (or) bicarbonate of sodium, and on adding this mixture to the sugar-5 containing liquid, the lime. is practically phosphate, acid to litmus alone thoroughly precipitated. Themore basic soluble phosphate, etc., is far more efiicie'nt in its'lime removing power than phosphoric acid or a hosphate acid to litmus. A solue ble phosp ateofsoda-mfly be used to m cipitate the excess lime, and very good results are obtained thereby. Such a soluble phosphate or equivalent isadded in correct proportion, determined or checked, by experiment, and the solution is then heated to near the boiling point with safety, as neither sugar nor reducingv sugar is destroyed nor attacked, but the lime is almost table by lime.

completely precipitated immediately as an insoluble phosphate. or other compound. The separate ingredients for forming any of these precipitants may be' added separately to the juice with equally good effect. The resulting precipitate settles Very quickly in the solution, leaving it bright and clear as well as very light colored and suitable for making the very best grade of raw sugar or even a sugar for direct consumption. This second precipitation, with a phosphate neutral or alkaline to litmus, further removes the iron from the juice, which greatly improves the latter for making either direct consumption sugars or raw sugars for refining. It removes also the small pieces of cane fibre or bagasillo which escape the first efiort at clarification and which if left in the juice find .their way into the raw sugar, where they retain their moisture and become centers of infection by micro-organisms which ferment the sugar and cause large deterioration losses in storage and transportation.

'The precipitation with the llme and with the phosphate can be easily carried out without any special machinery or appliances as the sedimentations may take place in ordinary tanks.

The two precipitates, settled from their respective solutions, after once diluting and ecanting, may be combined and filterpressed. The efiicient fertilizer as it contains practically all of the nitrogenous matter of the raw juice and-all the phosphatic matter of the defecant. This hosphatic matter, further, is nearly all in t e form immediately available to plants as food, and the littlethat may not be immediately available will gradually become available in the'soil.

To the fresh cold cane juice, milk of lime or dry lime is added be beyond the point of alkalinity to litmus and sutficient to precipitate completely all those substances precipi- This' will be about 030% or 040% lime on the Weight of the juice. An average juice is acid and requires 02% lime to neutralize to litmus and .0a% lime to neutralize to phenol phthalein. It will require about 03% ,to 04% lime to precipitate fully all the precipitable matters. 'lhis limed juice is heated in Louisiana to about 105 F. to efiect complete precipitation; in Porto. Rico to about 150 18. At these moderate temperatures no invert sugar is destroyed. The juiee is settled and the clear press cake may be used as anjuice decanted or the juice is filtered. To the clear juice'is now added about 02% of actual acid calcium phosphate and enough sodium carbonate to insure a neutral or approximately neutral reaction to litmus in the sugar solution. Part of the acid phosphate precipitates the free lime and the remainder reacts with the sodium carbonate to produce phosphate of soda, which immediately combines with the lime of the dissolved lime salts in the solution, precipitating this lime. The amount of this sodium carbonate is about one-third of the acid phosphate used. Phosphoric acid can be used as a substitute for acid phosphate of lime; so also may one employ phosphate of soda directly instead of forming it in the sugar solution. After adding these re-agents the temperature is spirit of the invention as defined in the appended claims.

Having thus described my invention, 1 claim as new and desire to secure by Letters Patent z- 1. A process for defecating sugar containing liquids which consists in adding to said liquids sufficient lime to give a complete precipitation of all substances precipitable by lime and to impart a strong alkalinity to the sugar containing liquid, maintaining said liquid at a temperature ranging from F. to 150 F, separating the precipitate, subjecting the solution of strong alkalinity to the action of a mixture of phosphoric acid and sodium carbonate to pre cipitate both the free lime'and the lime contamed therein in the form of dissolved lime salts, and then raising the temperature of the liquid to a point above 150 l. to facilitate the last mentioned reactions.

2. A. process for defecating sugar contaming liquid which consists in adding to said liquid sufiicient lime to give a complete precipitation of all substances'precipitable by lime and leave the liquid in a state of strong alkalinity, maintaining said liquid at a degree of temperature between 105 F. and 150 F, and separating the precipitate, sub ecting the solution of strong alkalinity to the action of a mixture of an aci phosphate and a sodium salt to precipitate both the free lime and the lime remaining in the liquid in. the form of dissolved lime salts, the last mentioned reaction being carried out at a dgree of temperature in excess of 150 F.

3. A process for defecating sugar containtion of a. mixture of phosphoric acid and ing liquids which comprises adding to said sodium carbonate to precipitate the free liquid .03% to 04% of lime to cause prelime in solution and the lime contained in 10 cipitation of matter in the liquid and impart said solution in the form ofldissolved lime n a strong alkalinity to the'sugar containing salts, and raising'the temperature of the liquid, separating the precipitate subjecting solution in excess of 150 F. the solution of strong alkalinity to the ac- WILLIAM DODGE HORNE.