MXPA06010441A - Sugar cane juice clarification process - Google Patents

Abstract

A process to clarify raw sugar cane juice, which comprises adding a source of lime, adding an anionic inorganic colloid or polyacyrlamide, and carbonating.

Description

PROCESS OF CLARIFICATION OF JUICE OF CANA DE SUGAR Field of the Invention The invention relates to an improved process for clarifying sugarcane juice without purification through the use of an anionic inorganic colloid or polyacrylamide polymer, particularly together with a carbonation process. Background of the Invention Sugarcane juice is an extremely complex liquid medium, which contains many organic and inorganic constituents in suspended / decantable and suspended / colloidal, soluble form. Sugarcane for human consumption is produced by clarifying sugarcane juice using an extraction process, which is then processed and concentrated to obtain sugar. Clarification is therefore an essential step to obtain high yields and high quality sugar. The clarification process needs to remove components other than sucrose and, at the same time, minimize sucrose loss and color formation. The sulfation process is currently the most widely used process to clarify cane juice. It consists of absorption of S0 (sulfur dioxide) by the juice, Ref .: 174690 reducing its original pH to levels between 3.7 and 4.2. The use of the sulphation process involves: (a) inhibition reactions that cause color formation; (b) coagulation of suspended colloids; and (c) formation of a CaS03 precipitate (calcium sulfite). In addition, it also reduces the viscosity of the juice and consequently of the syrup, masecuitos and molasses, facilitating evaporation and baking operations. However, the sulphitation process has problems which the sugar / alcohol industry may wish to solve, including (a) inversion of sucrose due to the low pH during the process; (b) potential environmental problems and external corrosion in the area, caused by any emission of S02 / S03; (c) incrustation and corrosion of the evaporation equipment; and (d) presence of sulfite in the final sugar. Another method to clarify the juice of sugarcane is carbonation, which generally uses the treatment with lime and controlled addition of carbon dioxide (C02). However, this process results in (a) increased loss of inverted sugar in the juice (fructose and glucose) due to the high alkaline pH (generally pH of about 10) and the high temperatures used for the process, adversely affecting the yield of alcohol production from the final molasses, and (b) difficulty in filtering the precipitates from "clarifiers, which requires a higher investment in equipment, higher operational costs and a more complex operation." Therefore, there is a desire to have a clarification process which is superior to the sulphitation process, but which avoids problems with carbonation The present invention provides such a process Silicate microgels are used in water purification and water flow processes The application WO 99/61377 describes a process for clarifying water streams containing biosolids resulting from the food processing and organic waste, which involves contacting the stream with an anionic colloid, which can be r a silicate microgel and an organic polymer to flocculate the biosolids. For the clarification of sugarcane juice it is desired to minimize the accumulation of silica in the juice and in the production heating equipment. The process of the present invention solves this problem while avoiding the problems with the sulphitation of the prior art and carbonation processes. SUMMARY OF THE INVENTION The invention comprises a process for clarifying sugarcane juice which comprises at least the steps of addition of lime; addition of anionic inorganic colloid, a polyacrylamide polymer, or both the colloid and the polymer; and carbonation. More specifically, the invention comprises an improved process for clarifying sugarcane juice by carbonation, which comprises the addition of an anionic inorganic colloid or polyacrylamide polymer, according to the following steps: a) heating sugar cane juice without purify to be clarified; b) add a source of lime; c) adding an anionic inorganic colloid, a polyacrylamide polymer, both the colloid and the polymer sequentially, or a mixture thereof; d) carbonation by adding carbon dioxide; and e) decanting the formed precipitates to produce a supernatant which contains the juice of sugarcane. Optionally, the addition in step c) may then be, instead of before, the carbonation stage d), ie, current below the carbonation stage. The process optionally further comprises: a) heating the supernatant of step e) • above; b) Carbonate when adding carbon dioxide; and c) decanting any precipitates formed to produce an additional supernatant which contains sugar cane juice. Detailed Description of the Invention According to a specific embodiment of the invention, the clarification process of the present invention comprises the steps of: a) heating the sugarcane juice without purifying to be clarified; b) add a source of lime; c) adding an anionic inorganic colloid, or a polyacrylamide polymer, or both the colloid and the polymer sequentially, or a mixture of the colloid and the polymer; d) Carbonate when adding carbon dioxide; and e) decanting the precipitates formed to produce a supernatant which contains sugar cane juice. In particular, the present invention provides an improved process for clarifying sugarcane juice without purification using carbonation wherein the improvement comprises addition of an anionic inorganic colloid, and a polyacrylamide polymer, both the colloid and the polymer sequentially, or a mixture of colloid and polymer. The preferred anionic inorganic colloid is silicate microgel.

During step a), the unpurified sugarcane juice is heated to a temperature between about 45 ° C and about 90 ° C, preferably between about 50 ° C and about 85 ° C, and still more preferably between about 55 ° C C and approximately 80 ° C. The heating of the juice has the purpose of facilitating downstream processes by accelerating chemical reactions and improving the coagulation and sedimentation of colloids and other non-sugars. The limiting step b) is the addition of a source of lime (CaO) to the cane juice without purification. Any suitable source of lime can be used, but lime slurry (Ca (OH) 2) or calcium saccharate is preferred. The addition of the lime source increases the pH of the sugarcane juice. The lime is added to a maximum concentration of about 2% by weight of the solids content of the juice. This addition has the purpose of eliminating juice dyes, neutralizing organic acids, and forming calcium phosphate precipitate, which before sedimentation carries the impurities present in the liquid. Between steps b) and c), it is particularly advantageous that a time interval between about 0.5 and about 10 minutes is optionally observed. In step c) of the process of the present invention an inorganic anionic colloid is added. Such colloids useful in the process of this invention include silica-based anionic inorganic colloids and mixtures thereof. Inorganic anionic silica-based colloids include, but are not limited to, colloidal silica, aluminum-modified colloidal silica, polysilicate microgels, polyaluminosilicate microgels, polysilicic acid, and polysilicic acid microgels and mixtures thereof. For those colloids that contain aluminum, aluminum may be on the surface and / or inside the particles. The anionic inorganic colloids used in this The invention may be in the form of a colloidal silica having an S > 70%, generally > 75% and containing approximately 2 to 60% by weight of SiO2, preferably and approximately 4 to 30% by weight of SiO2. The colloid may have particles with at least one surface layer of aluminum silicate or it may be a silica sol modified in aluminum. The alumina content of the surface modified silica sol may be in the range of 2 to 25%. The colloidal silica particles in the sols commonly have a specific surface area of 50-1200 m2 / g, more preferably and approximately 200-1000 m2 / g. The silica sol can be stabilized with an alkali in a molar ratio of SiO2: M20 from 10: 1 to 300: 1, preferably 15: 1 to 100: 1 and more preferably 6: 1 to 12: 1 (M is Na, K, Li, or NH).

Preferred for use in the process of the present invention are the silicate microgels. The microgels are distinctive of colloidal silica since the icrogel particles usually have surface areas of 1000 m2 / g or more and the microgels are comprised of silica particles of 1-2 nm in diameter connected together in chains and three-dimensional networks. The polysilicate microgels, also known as active silicas, have ratios of Si02, Na20 from 4: 1 to about 25: 1, and are. discussed on pages 174-176 and 225-234 of "The Chemistry of Silica" by Ralph K. Ller, published by John Wiley and Sons, NY, 1979. Polysilicic acid generally refers to those silicic acids that have been formed and partially polymerized in the pH range of 1-4 and comprise silica particles generally smaller than a diameter of 4 nm, which after that polymerize in • chains and three-dimensional networks. The polysilicic acid can be prepared according to the methods described in Patents of the United States of North America 5,127,994 and 5,626,721. Polyaluminosilicates are polysilicate or polysilicic acid microgels in which aluminum has been incorporated into the particles, on the surface of the particles or both. The polysilicate microgels, polyaluminosilicate microgels and polysilicic acid can be prepared and stabilized at acidic pH. The microgel size can be increased by any of the known methods such as aging, microgel, changing the pH, changing the concentrations, or other methods, known to those skilled in the art. The use of silicate microgels provides the advantage in the process of the present invention of reducing oxidation in equipment and therefore problems of equipment cleaning and maintenance. The polysilicate microgels and polyaluminosilicate microgels useful in this invention are commonly formed by the activation of an alkali metal silicate under conditions described in United States of America 4,954,220 and 4,927,498. However, other methods can also be employed. For example, polyaluminosilicates can be formed by the acidification of silicate with mineral acids containing dissolved aluminum salts as described in U.S. Patent 5,482,693. The alumina / silica microgels can be formed by the silicate acidification with an excess of aluminum, as described in US Pat. No. 2,234,285. In addition to the conventional silica sols and silica microgels, the silica sols such as those described in European patents 491879 and 502089 can also be used for the anionic inorganic colloid in this invention. These are commonly referred to as suns of "low S value". European Patent 491879 describes a silica sol having an S value in the range of 8 to 45% where the silica particles have a specific surface area of 750 to 1000 m2 / g, which has been modified on the surface -with 2 to 25% alumina. European Patent 502089 discloses a silica sol having a molar ratio of Si02 to M20, wherein M is an alkali metal ion and / or an ammonium ion from 6: 1 to 12: 1 and containing silica particles having a specific surface area of 700 to 1200 m2 / g. Included within the scope of the colloidal silica sols useful in the present invention are colloidal silica sols having a low "S" value. The S value is defined by Iler and Dalton in J. Phys. Chem., 1956, vol. 60, p. 955-957. The S value is a measurement of the degree of aggregation or microgel formation and a lower S value indicates a higher microgel content and is determined by measuring the amount of the silica, in percent by weight, in the dispersed phase. The dispersed phase consists of anhydrous silica particles together with any water that is immobilized on the surface or inside the particles. In the process of the present invention the preferred silicate microgel is added to the mixture of sugar cane juice and lime source in step c), preferably in an amount of between about 50 ppm and about 500 ppm, more preferably about 50 ppm to about 200 ppm. Silicate microgels are commercially available, such as Particlear® manufactured by E. I du Pont de Nemours and Company of Wilmington DE and are produced by any method known in the art. U.S. Patent 6,060,523 and U.S. Patent 6,274,112 describe improved processes that allow reliable preparation of microgels. The silicate microgel is typically obtained from sodium silicate. It is also designated as silicon dioxide or active silica microgel, which comprises between about 0.5% and 2% of Si02, particular and about 1% of SiO2 solution. Alternatively, a polyacrylamide polymer is employed in step c) of the process of the present invention. An amount of about 1 ppm to about 10 ppm is employed, preferably from about 2 ppm to about 5 ppm. Polyacrylamide polymers suitable for use herein include primarily anionic polymers, which carry the same charge as the particles of the suspension in unpurified juice. Preferred are partially hydrolyzed polyacrylamides having a moderate degree of hydrolysis (between about 15% and about 40% hydrolyzate). Polymer molecular weights are usually above 1,000,000. Suitable polyacrylamides are commercially available for example from Kemwater Brasil S.A., Sao Paulo, Brazil. The silicate microgel and the polyacrylamide can both be used in the process of the present invention by sequentially adding them in any order or as a mixture. The use of the silicate microgel is preferred due to faster dewatering during filtration resulting in better filtration. The Applicant has developed an improved carbonation process for cane juices, comprising the addition of an anionic inorganic colloid, preferably silicate microgel, and adjusting it to the operating conditions of a modified and improved carbonation process, thereby solving the problems for its industrial implementation and allow higher yields of purer sugar. The process of the present invention recovers the waste C02 from fermenters and replaces S02 currently used in the sulphation process for clarification of juice with the recovered CO 2. It also decreases the formation of oxidation in evaporators and heat exchangers by removing oxidation-forming compounds from the juice through the improved clarification process. Additionally, the process of the present invention solves the problem of filtering the precipitation / sedimentation generated by the traditional carbonation processes, and does not increase the loss of inverted sugars. Additionally, the process of the present invention reduces the consumption of CaO compared to traditional carbonation processes. The process of the present invention reduces losses of sucrose by inversion, obtains better purification of cane juice by removal of more organic and inorganic impurities, reduces equipment corrosion due to the absence of S02, decreases oxidation in evaporators, and provides production improved sugar According to a preferred embodiment of the invention, the microgel is activated by an acid, particularly C02, because C02 is abundant in sugarcane processing facilities that produce ethanol by fermenting juice and / or molasses. A time interval between step c) and the subsequent one is advantageous and this time interval is typically between 0.5 and about 10 minutes. In step d), C02 is added, preferably in sufficient quantity to form calcium carbonate precipitates. The flow of C02 is regulated to control the foam and reaction time. In a preferred embodiment of the present invention, C02 is added through a carbonation column, counter flow with unpurified sugar juice with lime fed at the top of the column. Optionally the anionic inorganic colloid, or the polyacrylamide, or each of the first, or a mixture thereof, can be added after the carbonation step instead of adding to the carbonation step in the amounts previously described. After the carbonation step, the decanting step e) is undertaken. In step e), sugarcane juice is purified by removing impurities precipitated as solids. The decanted juice is removed from the top of the decanter and supplied to an evaporator, where it is concentrated. The precipitated and settled materials have a solid concentration of about 10 ° Be and are usually taken from the bottom of the decanter and sent to a filtration sector where the materials are subsequently filtered to recover the sugar. According to the invention, the required decant time is less than one hour, usually about 30 minutes. The pH of the supernatant, after this first carbonation, is usually between about 8 and 10, preferably about 9. The carbonation process of the present invention is particularly advantageous when driving using the final supernatant as the starting material in a second carbonation. In this way, the present invention further comprises a carbonation process which, in addition to the steps described above, additionally comprises the following steps: a) heating of the supernatant which results from the process described above; b) carbonation when adding carbon dioxide; and c) decanting any precipitated solids to produce a supernatant addition containing sugarcane juice. During step a), the supernatant is heated at temperatures between about 60 ° C and 90 ° C, preferably about 70 ° C. The heating is followed by a carbonation step. The operating conditions are employed which avoid excessive foaming and generate the expected neutral pH for the juice. In a preferred embodiment, C02 is added through a second carbonation column, against flow with clarified juice fed into the top of such a column. This column adjusts the pH of the treated juice. The final pH is typically from about 6.5 to about 8, preferably and about 7. Any precipitated solids are decanted to produce an additional supernatant which contains sugar cane juice. Often there are no precipitates formed during the second carbonation. The process of the present invention as described in the present invention makes use of carbonation to clarify sugarcane juice, presenting advantages over the sulfation process in higher yields with better quality product. The elimination of sulfur use in the process of the present invention has a remarkable advantage, not only in cost, but also results in higher process safety, less corrosion and / or oxidation of heating equipment, and less environmental degradation. The investment of sucrose in the process of the invention is reduced by between about 1.5% and 2.5%, or which represents an increase in yield. As a direct consequence of this aspect a superior yield in crystal sugar production is obtained using the same equipment, since sucrose forms sugar crystals and not reducing sugars. This simple standard demonstrates that the process of the present invention is significantly better than those of the prior art. The process of the present invention results not only in a lower loss of sucrose, but also in superior removal of non-sugars such as starches, proteins, suspended solids and dissolved solids. The protein and starch are surprisingly reduced, typically less than 3 ppm in the clarified juice. The process of the present invention produces a purer product with better characteristics such as color. Purity (Purity = POL / Brix) can be increased for two different reasons: (i) higher sucrose content (higher numerator) or (ii) lower content of non-sugars (lower denominator). The higher reduction in the sucrose inversion favors additional crystallization since the process will suffer less interference from the impurities. The lower amount of impurities is very desirable and benefits the total operation, since it reduces the total volume to be process throughout the system. Therefore, there is less fouling / oxidation in the heating equipment, especially the evaporator, which then does not need to be cleaned frequently. This reduces maintenance and steam energy costs and increases safety for employees who conduct such cleaning operations in the industrial facility. Additionally, the impurity reduction provided by the process of the present invention results in much higher sugar quality. The impurities and color (Icumsa standard (420 nm) are reduced by improving its market value.A color measurement of the clarified sugar juice having a maximum of 7100, preferably a maximum of 6000, and more preferably a maximum of 5000, is In addition to being a safer process with superior product, the process of the present invention provides a reduction in impurities in the juice between about 1.5% and 2.0% For all the above reasons, the process provides increased total efficiency. they are processed under the same installed capacity, thus increasing the production of sugar.This increase in sugar production does not affect the production of alcohol from molasses.The reducing sugars remain in the final molasses and can be converted to ethanol. Therefore, due to the reduction in sucrose investment, there will be less final molasses for alcohol production. to maintain the same desired levels, it is only required to divert more unpurified juice to the distillery, skipping the stages of clarification, evaporation and vacuum of the process. In addition to the above advantages, the process of the present invention improves the reduction of juice turbidity, reduction of organic colloids (for example starch), and improved coagulation and flocculation. In particular, the time to form flakes is reduced and the size of the flakes is reduced. In this way, the sedimentation time is totally reduced. An additional advantage is the optional removal of the addition of flocculation agents. The carbonation process of the present invention is especially advantageous for use at temperatures between about 70 ° C and about 80 ° C, thus avoiding a negative effect on alcohol production yield from the final molasses. Simultaneously, the energy cost and settling time are reduced. Keeping the juice at a high temperature leads to the degradation of reducing sugar and inversion to form organic acids, resulting in a decrease in purity and pH. The reduction in decanting time of the process of the invention reduces the loss of sugar by inversion. The fact that the new process generates precipitates / sediment with less filtration characteristics than traditional carbonation is exceptionally advantageous for the sugar / alcohol industry. The sediment that results from industrial carbonation is difficult to filter, requiring the installation of pressure filters, representing a large financial investment and a more complicated process. This is one of the main reasons why the carbonation process of the prior art is not more widely used. The process of the present invention generates precipitates / sediments which do not require the installation of press filters, since the vacuum rotation filters can be used. In addition to better filtration, the precipitates / sediments resulting from the process of the present invention comprise a minor amount of sucrose. The loss of sucrose represents less than 0.4% of the total sugar that enters the plant, thus representing approximately half of the current losses. Additionally, opposed to traditional carbonation processes, the consumption of lime is much lower. It is less than 2% by weight of solids present in the juice. In traditional carbonation processes, the consumption of lime is between 6 to 10% by weight of solids present in the juice. In this way, the process of the invention is a faster and safer process, which results in a significant increase in performance, generates superior quality and avoids problems in the conventional carbonation process. It is useful to clarify sugar cane juice more efficiently. As those skilled in the art will understand, numerous modifications and variations of the scope of the invention are possible in the light of the foregoing teachings. It should therefore be understood that the invention can be exemplified in other forms besides those specifically described herein.

EXAMPLES Unpurified sugar cane juice from the past growing season typically has the following properties: pH 5.2-5.8, turbidity 5000, color 10,000 to 12,000 using ICUMSA # 4, Brix 14 to 16, and total reducing sugars from 13 to 15. Example 1 The juice of sugarcane is heated without purifying (1 liter) slowly at 80 ° C in a 2 liter beaker, followed by the gradual addition of 33 ml of whitewash (calcium hydroxide, "Ca (0H) 2) to increase the pH to 8. 5. The solution is maintained for approximately one (1) minute, after which 160 ppm of available silica microgel is added as Particlear® from E.I. du Pont de Nemours and Company, Wilmington, DE. The solution is then maintained for approximately 2 minutes. The pH of the solution is maintained at 8.4 by the simultaneous addition of lime milk and carbon dioxide gas. Lime milk is added (105 ml) to reach a total of 2% CaO by weight in solids content. The carbon dioxide is introduced in a stationary proportion of 260 cc / minute. Finally, the pH of the solution is decreased to 7.0 by bubbling additional carbon dioxide into the solution. The total carbonation time is 15 minutes. During carbonation, foam formation is controlled by regulating the flow rate of C02 and due to the presence of microgel. The volume of precipitate (in the original carbonation beaker) is 160 ml, after 45 minutes of sedimentation. This is followed by a filtering stage, where 100 ml of the concentrated precipitate is filtered in a vacuum of 58 mm Hg (7733 Pa). The filtration time for a 75 ml sample is 6 minutes, with a dry time for the paste of 8 minutes. The final pH of both the filtrate and the supernatant liquid sugar juice is 7.9. The supernatant juice and juice filtered under vacuum are analyzed for pH, color, turbidity, Brix, and total reducing sugars. The excellent clarity and transparency of the juice is evident during the process. The turbidity of the final sugar juice is 16 NTU, and its color is 6436 using the ICUMSA # 4 method. He Brix is 17.8. The total reducing sugars are 16.7. Comparative Example A The sugarcane juice is processed in the milling using the sulphation process. The juice is put in contact with S02, and whitewash (calcium hydroxide, Ca (0H) 2) to form a precipitate of calcium sulfite (CaS03). The coagulated precipitate is then separated from the supernatant. The product has a pH of 6.5, color of 9030 using Method # 4 ICUMSA, Brix of 15.8. The total reducing sugars of 14.6, and sulphites of 150.

Example 2 Sugar cane juice is processed without purification as in Example 1. The final product has a pH of 8, turbidity of 54 NTU, color of 7096, using the method # 4 ICUMSA, Brix of 17.0 and total reducing sugars from 16.2 Example 3 Unpurified sugarcane juice is continuously processed in a pilot plant using 2 to 3 liters of juice per hour and runs of 3 to 4 hours per day using the process of the present invention. The sugar cane juice is heated without purifying at 55 ° C, followed by the addition of lime slurry (calcium hydroxide Ca (OH) 2) to increase the pH to 10.5. The consumption of milk of lime is approximately 1.2% of CaO by weight in solids content. The solution is maintained for approximately five (5) minutes. The solution is then carbonated in a counter flow column. The carbon dioxide is introduced from the lower part, in a steady flow rate, in order to obtain a final carbonated juice pH of 9.5, downstream of the column. In the column, the carbonation time is 10 minutes. After which 150 ppm of available silica microgel is added as Particlear® from E. I. Du Pont de Nemours and Company, Wilmington, DE. The solution is then maintained for approximately 5 minutes. The microgel carbonated juice is then sent to a decanter in order to separate the precipitate from clarified juice (supernatant). Finally, the supernatant is heated to 70 ° C and the pH of this hot solution is decreased to 7. 0 by bubbling additional carbon dioxide into the solution, in a second column of carbonation against flow. The precipitate from the decanter is sent for characterization and the results are given in Table 1 and 2 below. - Table 1 compares the properties of sugar juice made using the process of the present invention according to Field 3 to average results reported in the literature for carbonation processes by not washing silica microgel. Table 1 Table 1 shows the improvement in color, brix, purity, starch, and total reducing sugars using the process of the present invention. Table 2 compares the properties of the sugar juice made using the process of the present invention according to Example 3 to average results reported in the mills for sulphation processes. Table 2 Table 2 shows the improvement in color, brix, purity, starch, sucrose, and total reducing sugars using the process of the present invention. Example 4-12 and Comparative Examples AF Carbonate materials are filtered from the process of Example 3 using 200 ml of suspension volume at three different pressures as indicated in Table 3 using a Bo ela filter device, available from Bokela, Karlsruhe, Germany. The materials from a traditional sulphation process are filtered under the same conditions. The material using the process of the present invention shows solids which are similar fibers and form a filter cake of 16-27% solids, which is easier and faster to dewater. In contrast, material from the comparative sulphation process forming a gel-like filter paste of approximately 23% solids, which is more difficult to dewater. The turbidity of the resulting (filtered) sugar juice is approximately 11,000-12,000 NTU for the comparative sulphation process and approximately 4,000-5,000 NTU for the process of the present invention. The specific results are listed in Table 3 below. Table 3 The additional runs are performed as described above in order also to compare the carbonation method of the present invention using silicate microgel with (a) the carbonation process of the present invention using the polyacrylamide polymer instead of the silicate microgel , and (b) the traditional prior art carbonation process. The results are indicated later in Table 4. Table 4 Also in this case, according to the above results, the material using the process of the present invention shows percent solids in the paste similar to Examples 4-6 above. However, as regards the comparison with the sulphation process, the turbidity of the filtrate from the process of the present invention using silicate or polyacrylamide microgel is better and the filtration of the paste is easier. The process of the present invention using silicate microgel is faster to dewater. Further, in terms of operation of the filter, the paste from the carbonation process of the present invention using the silicate microgel is best released from the filter screen, as compared to the other processes. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (1)

Claims Having described the invention as above, the content of the following claims is claimed as property: 1. A process for clarifying unpurified sugar cane juice characterized in that it comprises the steps of adding a lime source; addition of a silicate microgel having a surface area of 1000 m2 / g; or higher; and carbonation. 2. The process in accordance with the claim 1, characterized in that it comprises the following steps: a) heating the sugarcane juice without purifying to be clarified, b) adding a lime source, c) adding a silicate microgel having a surface area of 1000 m2 / g. more, d) carbonation by adding a carbon dioxide, and e) decanting precipitates formed to precipitate a supernatant containing sugarcane juice 3. The process in accordance with the claim 2, characterized in that it also comprises the following additional steps: a) heating the supernatant; b) carbonation by adding carbon dioxide; and c) decanting any precipitates formed to produce an additional supernatant which contains sugar cane juice. -4. The process according to claim 2, characterized in that the silicate microgel is added after step d) instead of before step d). 5. The process according to claim 2, characterized in that the polyacrylamide or polyacrylamide polymer and silicate microgel are added after step d) instead of before step d). 6. The process according to claim 2, characterized in that the sugarcane juice is not purified. it is heated at a temperature between about 45 ° C and about 90 ° C. 7. The process according to claim 2, characterized in that the lime is added to the cane juice without purification to achieve a maximum concentration of 2% by weight solids of the cane juice without purifying. 8. The process according to claim 7, characterized in that the lime is in the form of whitewash (Ca (0H) 2) or calcium saccharate. 9. The process according to claim 2, characterized in that the silicate microgel is added in an amount of about 50 ppm to about 500 ppm. 10. The process according to claim 2, characterized in that the addition of silicate microgel is carried out after a period of approximately 0.5 to approximately 10 minutes after adding the lime 11. The process according to claim 2, characterized in that the carbon dioxide is added after a time interval of about 0.5 to about 10 minutes which has elapsed after the addition of the silicate microgel. The process according to claim 2, characterized in that the precipitates have a solid concentration of about 10 ° Baumé, and the precipitates are subsequently decanted to separate the juice of purified sugarcane from the precipitates. 13. The process according to claim 2, characterized in that the settling time is less than one hour. The process according to claim 2, characterized in that the final pH of the supernatant is from about 6.5 to about 8. 15. The process according to claim 3, characterized in that the supernatant is heated at temperatures between about 60 ° C. and approximately 90 ° C. 16. The process according to claim 16, characterized in that the carbon dioxide is added in an amount sufficient to lower the pH of the supernatant of the sugar cane juice to about 7.0. 17. The process according to claim 3, characterized in that the supernatant has a maximum color of 6000. 18. The juice of sugarcane characterized in that it is produced by the process according to claim

1.