Alkaline earth metal oxide and carbonate compositions for sugar beet treatment

Abstract

The present invention relates to a kit for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets, said kit comprising or consist in: - a first particle composition having quicklime, wherein the weight fraction of said first composition relative to the weight of said kit is greater than 30%, preferably greater than 50%, in particular greater than 70%; and - a second particle composition having a CaCOs content or a CaCOs and MgCOs content of at least 90% in weight, in particular at least 95% in weight relative to said second composition, a d10 greater than 0.8 µm and a d50 greater than 2 µm and a Carr's index lower than 50%, wherein the weight fraction of said second composition relative to the weight of said kit is greater than 15% but less than 70%.

Description

Technical Field

[0001] The present invention relates to a kit for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets, a process for treating an aqueous composition comprising saccharose, in particular a juice from sugar beets, a use of said kit for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets, as well as a alkaline earth metal carbonate particle composition for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets and its use.Background Art

[0002] Typically, the purification of raw sugar juice relies on a quicklime-based calco-carbonic treatment, as shown in Figure 1. In this process, quicklime is generated in a lime kiln located on a site where the sugar juice treatment takes place. Calibrated limestone is calcinated in the lime kiln using preferably coke or anthracite as fuel. Both the limestone and certain fuel (solid fuel) require pre-screening to remove undesirable components that require specific treatment, forming a first waste stream.

[0003] During the lime calcination in step S1, the lime kiln produces fumes containing carbon dioxide (CO 2 ). These fumes are washed through a water scrubber to remove dust and other types of particles. The captured dusts and particles are then settled in a water pond (forming a second waste stream) before recirculating the water. A portion of the CO 2 -containing fume flow is then transferred to carbonation vessels of the sugar juice purification process where CO 2 injected in the sugar juice re-carbonates hydrated lime therein. Another part of the fume flow is released into the atmosphere.

[0004] The quicklime produced in the kiln is then preferably mixed typically in a trommel with an aqueous solution, in particular a de-sweetening juice leading to a suspension of hydrated lime also designated as milk of lime or MOL. The de-sweetening juice stems from the sludge treatment, wherein the sludge being essentially composed of calcium carbonate (resulting from the re-carbonation of the hydrated quicklime) separated in the filtration stages in steps S6 and optionally S8. Typically, the de-sweetening juice comprises a residual amount of saccharose. The milk of lime is essentially a calcium hydroxide suspension. The duration of the completion of the hydration reaction (a.k.a. slaking) depends for instance on the calcination level, particle size distribution (PSD), fuel used for the calcination, and homogeneity of the quicklime resulting from the calcination in the kiln in step S1. Generally, the lime is produced with a single shaft kiln located on the site where the sugar juice treatment takes place. The lime availability is limited by the maximum kiln capacity and potentially impacted by any breakdown or productivity issue of this single lime kiln. The quality and uniformity of calcination can drastically fluctuate and is usually not measured between the kiln outlet and the inlet of the milk of lime preparation unit. This potential heterogeneity of calcination creates fluctuating amount of unburnt or overburnt material which can impact the milk of lime quality, the process efficiency and the net energy consumption per ton of reactive lime. The amount of unburnt and overburnt material (a.k.a. sintered quicklime) is sorted out through further separation equipment such as classifier, decanter, screeners, cyclone, or sand screws at the outlet of the milk of lime unit and generates a third flow of wastes.

[0005] Linked to the lime calcination fluctuations, the slaking process necessary to hydrate the lime can widely fluctuate and can reach a very long time as around 30 minutes and even much more. To enable enough reaction time for the slaking process, several maturation tanks are provided downstream from the trommel.

[0006] In step S3, the milk of lime is added into the raw juice in the preliming stage to increase smoothly the pH to a pH around 11.5 (measured at the reference temperature at 20°C) and initiate several chemical reactions producing precipitation, coagulation and flocculation of several non-sugar compounds present in the raw juice.

[0007] The pre-limed juice is then mixed with a second amount of milk of lime in the main liming vessel(s) in step S4.

[0008] After the main liming in step S4, the limed juice enters the carbonation vessels in step S5 where CO 2 is injected causing the carbonation of the hydrated lime, leading to the nucleation and growth of carbonated lime. This precipitate allows to remove impurities of the juice by adsorption or trapping. The CO 2 injection also causes a pH reduction of the limed juice generating several other reactions of precipitation, coagulation and flocculation. The carbonated lime generated is also used as filter aid for the subsequent filtration step.

[0009] The carbonated lime suspension is then filtered and / or decanted in step S6, allowing the separation of the precipitated materials primarily composed of calcium carbonate, and all non-sugar particles and impurities captured during the previous steps of the process.

[0010] A second carbonation in step S7 and a second filtration in step S8 occur to further remove residual calcium and remaining impurities to reach a sufficiently purified sugar juice before evaporation and crystallization.

[0011] Limitations related to this known process are: the generation of three waste streams: separated limestone fines, coke, anthracite fines associated with the calcination process in step S1 and unburned limestones and over burned lime in step S2, wastes captured by the water fumes treatment; atmospheric CO 2 emissions generated that are not concentrated enough to be captured and sequestered; water consumption used for fume treatment; fluctuating milk of lime quality and concentration linked to fluctuating conditions of calcination; long maturation for the slaking process; fluctuation and uncontrolled carbonated lime properties linked to sugar process parameters.

[0012] These drawbacks limit the efficacy of the sugar purification process shown in Figure 1. In particular, one cause of concern is the clogging occurring in the filtration stages in steps S6 and S8 due to uncontrolled and the too fine CaCO 3 particles produced in situ, or weak decantation.

[0013] To overcome these filtration weaknesses, it has been proposed to add filter aids such as organic or inorganic materials. However, such an approach is expensive.

[0014] US5480490A teaches to reuse the sludge generated during the sugar juice treatment. On one hand, the recycled sludge is reactivated (via calcination) and then serves as a source of CaO for the liming. On the other, the activated recycled sludge is injected in the preliming vessel as a separate stream to that of CaO source. In addition, such known measures do not allow to control the precipitated CaCO 3 properties, as well as the impurities, notwithstanding the fact that heavy investment are necessary for the sludge recirculation and regeneration. A poor control of the CaCO 3 recirculated particle characteristics and quantity can lead to a degradation of the purity of the filtered juice to the point that the result is worse with recirculated CaCO 3 than without. Likewise, Other prior art discloses sugar beet purification using a filter membrane and an introduction of CaCO 3 for the pre-liming stage, where CaCO 3 stems from raw limestone or recycled sludge. Nevertheless, these publications do not disclose the characteristics of the CaCOs, the measures to improve the filtration, a particle composition, nor milk of lime with predefined proportion of CaO and CaCO 3 .

[0015] The sugar purification process shown in Figure 1 is also not efficient in terms of CO 2 emissions. To overcome this issue, it has been proposed to replace a portion of the CaO source with a calcium carbonate particle composition to reduce the CO 2 footprint. However, the prior art is silent on the fact that CaO and that calcium carbonate sources are introduced simultaneously into the sugar beet suspension to be treated, both in the pre-liming stage and in the liming stage.Aims of the Invention

[0016] The invention aims to provide a solution to overcome at least one drawback of the teaching provided by the prior art.Summary of the Invention

[0017] For the above purpose, the invention is directed to a kit for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets, said kit comprising or consist in: a first particle composition having quicklime, wherein the weight fraction of said first composition relative to the weight of said kit is greater than 30%, preferably greater than 50%, in particular greater than 70% and wherein the first particle composition has a CaO content of at least 70% in weight, preferably at least 80% in weight, in particular at least 90% in weight relative to said first composition, and optionally a d 99 lower than 2 mm, preferably such as measured by sieve analysis; and a second particle composition having a CaCO 3 content or a CaCO 3 and MgCO 3 content of at least 90% in weight, in particular at least 95% in weight, preferably at least 97% in weight relative to said second composition, a d 10 greater than 0.8 µm, preferably such as measured by laser diffraction analysis, and a d 50 greater than 2 µm, such as measured by laser diffraction analysis and optionally a Carr's index lower than 50%, and optionally a d 99 lower than 2 mm, preferably such as measured by sieve analysis, wherein the weight fraction of said second composition relative to the weight of said kit is greater than 15%, preferably greater than 30%, in particular greater than 40%, but less than 70%.

[0018] According to specific embodiments of the invention, the kit comprises one or more of the following technical features, taken in isolation, or any combination thereof: the first particle composition has a t60 lower than 10 minutes, preferably lower than 8 minutes, more preferably lower than 5 minutes, in particular lower than 2 minutes; the d50 of the second particle composition is lower than 60 µm, preferably lower than 30 µm, in particular lower than 25 µm; the second particle composition has a specific surface BET higher than 0.5 m2 / g but lower than 3 m2 / g and / or a porous volume higher than or equal to 0.002 cm3 / g but lower than 0.01 cm3 / g; the cumulative content of Mn3O4, Al2O3, Fe3O4 and SiO2 is less than 5%, preferably less than 4%, preferably less than 3 % by weight relative to the second particle composition; the second particle composition has a MgCO3 content of less than 10% by weight relative to second particle composition; the CaCO3 of the second particle composition comprises aragonite and / or calcite, wherein the content of aragonite and / or calcite is higher than 95.5% in weight, preferably more than 99% in weight of said CaCO3 in a crystallized form; the kit is in the form of a ready-to-use particle composition, in particular the ready-to-use particle composition comprising or consisting of a mixed particle composition of the first and second particle compositions; the first and second particle compositions are separated from each other.

[0019] The invention is also related to a particle mixture for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets, said composition comprising or consisting in: a first particle composition having quicklime, wherein the weight fraction of said first composition relative to the weight of said mixture is greater than 30%, preferably greater than 50%, in particular greater than 70% and wherein the first particle composition has a CaO content of at least 70% in weight, preferably at least 80% in weight, in particular at least 90% in weight relative to said first composition, and optionally a d99 lower than 2 mm, preferably such as measured by sieve analysis; and a second particle composition having a CaCO3 content or a CaCO3 and MgCO3 content of at least 90% in weight, in particular at least 95% in weight, preferably at least 97% in weight relative to said second composition, a d10 greater than 0.8 µm, preferably such as measured by laser diffraction analysis, and a d50 greater than 2 µm, such as measured by laser diffraction analysis and optionally a Carr's index lower than 50%, and optionally a d99 lower than 2 mm, preferably such as measured by sieve analysis, wherein the weight fraction of said second composition relative to the weight of said mixture is greater than 15%, preferably greater than 30%, in particular greater than 40%, but less than 70%.

[0020] According to specific embodiments of the invention, the particle mixture comprises one or more of the following technical features, taken in isolation, or any combination thereof: the first particle composition has a t60 lower than 10 minutes, preferably lower than 8 minutes, more preferably lower than 5 minutes, in particular lower than 2 minutes; the d50 of the second particle composition is lower than 60 µm, preferably lower than 30 µm, preferably lower than 25 µm; the second particle composition has a specific surface BET higher than 0.5 m2 / g but lower than 3 m2 / g and / or a porous volume higher than or equal to 0.002 cm3 / g but lower than 0.01 cm3 / g; the cumulative content of Mn3O4, Al2O3, Fe3O4 and SiO2 is less than 5%, preferably less than 4%, preferably less than 3% by weight relative to the second particle composition; the second particle composition has a MgCO3 content of less than 10% by weight relative to the second particle composition; the CaCO3 of the second particle composition comprises in the form of aragonite and / or calcite, wherein the content of aragonite and / or calcite is higher than 95.5% in weight, preferably more than 99% in weight of said CaCO3 in a crystallized form; the particle mixture is a mixed particle mixture of the first and second particle compositions; the first and second particle compositions are separated from each other.

[0021] The invention also relates to process for treating, in particular purifying, an aqueous composition comprising saccharose , comprising: a) contacting the kit or the particle mixture with an aqueous solution, in particular a water used to clean filtrated sludges generated in step e) during a prior cycle or from another sugar beets purification process, thereby forming a milk of lime (MOL') and generating heat; b) alkalising and nucleating the aqueous composition by adding a first portion of said milk of lime, to a pH ranging from 8.5 to 11.4, leading to a pre-limed juice, preferably said pH being measured at 20°C; c) further alkalizing and nucleating the pre-limed juice by adding a second portion of said milk of lime, to a pH ranging from 11.0 to 13.0, leading to a limed juice, preferably said pH being measured at 20°C; d) at least one carbonation step consisting of introducing carbon dioxide (and optionally a portion of the second particle composition of the kit or particle mixture, or the particle composition) into the limed juice, leading to a carbonated limed juice, and e) at least one of filtering and / or decantation step consisting of removing particles in suspension in the limed juice or carbonated limed juice.

[0022] According to specific embodiments of the invention, the process comprises one or more of the following technical features, taken in isolation, or any combination thereof: the aqueous composition consists in or comprises a juice from sugar beets and wherein the aqueous composition comprises saccharose compounds and non-saccharose compounds; at least one of the first and / or second portion of the milk of lime is not filtered before being added to the aqueous composition and the pre-limed juice, respectively; recovering the heat, in particular at least some heat in stream generated in step a); the milk of lime has a fraction of dry matters of at least 5% by but less than of 75% preferably less than 50%, relative to the weight of said milk of lime, said dry matters comprising: at least 37% but less than 94% of Ca(OH) 2 by weight relative to said dry matters, and at least 14 % but less than 66% of CaCO 3 or CaCO 3 and MgCO 3 by weight relative to said dry matters, and optionally at least 2% but less than 30% of saccharose and non-saccharose compounds relative to said dry matters.

[0023] The invention also relates to process for treating, in particular purifying, an aqueous composition comprising saccharose , comprising: a1) contacting at least one particle composition with an aqueous solution, in particular water used to clean filtrated sludges generated in step e) during a prior cycle or from another sugar beets purification process, thereby forming a milk of lime and generating heat, wherein the at least one particle composition comprises a first particle composition and optionally a second particle composition, wherein the first particle composition comprises quicklime, the first particle composition having a t 60 lower than 10 minutes, preferably lower than 8 minutes, more preferably lower than 5 minutes, in particular lower than 2 minutes, wherein the second particle composition has a CaCO 3 content or a CaCO 3 and MgCO 3 content of at least 90% in weight relative to said second particle composition; a2) optionally recovering the heat, in particular at least some heat in stream generated in the previous step; b) alkalising and nucleating the aqueous composition by adding a first portion of said milk of lime, to a pH ranging from 8.5 to 11.4, leading to a pre-limed juice, preferably said pH being measured at 20°C; c) further alkalizing and nucleating the pre-limed juice by adding a second portion of said milk of lime, to a pH ranging from 11.0 to 13.0, preferably said pH being measured at 20°C, leading to a limed juice; d) at least one carbonation step consisting of introducing carbon dioxide into the limed juice, leading to a carbonated limed juice, and e) at least one of filtering and / or decantation step consisting of removing particles in suspension in the limed juice or carbonated limed juice.

[0024] The invention also relates to the use of the kit or the particle mixture for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets.

[0025] The invention also relates to a particle composition for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets, said composition having a CaCO 3 content or a CaCO 3 and MgCO 3 content of at least 90% in weight, in particular at least 95% in weight, preferably at least 97% in weight, a d10 greater than 0.8 µm, preferably such as measured by laser diffraction analysis, a d 50 greater than 2 µm, preferably such as measured by laser diffraction analysis, a d 99 lower than 2 mm, preferably such as measured by sieve analysis, and Carr's index lower than 50%.

[0026] According to specific embodiments of the invention, the particle composition comprises one or more of the following technical features, taken in isolation, or any combination thereof: the d50 of the particle composition is lower than 60 µm, preferably lower than 30 µm, preferably lower than 25 µm; the particle composition has a specific surface BET higher than 0.5 m2 / g but lower than 3 m2 / g and / or a porous volume higher than or equal to 0.002 cm3 / g but lower than 0.01 cm3 / g; the cumulative content of Mn3O4, Al2O3, Fe3O4 and SiO2 is less than 5%, preferably less than 4%, preferably less than 3% by weight relative to the particle composition; the particle composition has a MgCO3 content of less than 10% by weight relative to second particle composition; the CaCO3 of the particle composition comprises aragonite and / or calcite, wherein the content of aragonite and / or calcite is higher than 95.5% in weight, preferably more than 99% in weight of said CaCO3 in a crystallized form.

[0027] The invention also relates to the use of the particle composition for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets.

[0028] The invention also relates to process for treating, in particular purifying, an aqueous composition comprising saccharose, preferably said aqueous composition being a juice from sugar beets, in particular said aqueous composition comprising saccharose compounds and non-saccharose compounds, said process comprising: a) contacting quicklime with an aqueous solution, in particular a water used to clean the filtrated sludges, thereby forming a milk of lime and generating heat; b) alkalising and nucleating the aqueous composition by adding a first portion of said milk of lime and a first portion the particle composition, to a pH ranging from 8.5 to 11.4, leading to a pre-limed juice, preferably said pH being measured at 20°C; c) further alkalizing and nucleating the pre-limed juice by adding a second portion of said milk of lime and a second portion of the particle composition, to a pH ranging from 11.0 to 13.0, leading to a limed juice, preferably said pH being measured at 20°C; d) at least one carbonation step consisting of introducing carbon dioxide (and optionally a third portion of the particle composition) into the limed juice, leading to a carbonated limed juice; and e) at least one of filtering and / or decantation step consisting of removing particles in suspension in the limed juice or carbonated limed juice.

[0029] The measures of the invention allow an accurate and ponderal dosage of liming product which enables potential consumption reduction, especially when the milk of lime MOL' is prepared in batch.

[0030] Furthermore, they permit a faster reaction time with regard to pH action.

[0031] Also, thanks to these measures, the CO 2 injection amount in the carbonation vessels is reduced, as the composition according to the invention achieves the same efficacy as the known compositions with a lower amount of calcium, thereby a lower amount of CO 2 is required to neutralize the treated juice composition. This has an impact on energy consumption (less energy to condition the CO 2 in the carbonation vessels and to calcine limestone) and investment requirement as the carbonation vessel capacity can be reduced, notwithstanding the resulting process time gain.

[0032] Equally, they permit to reduce the amount of sludge produced.

[0033] Moreover, these measures allow to adjust the ratio of components on site depending on the current need.

[0034] Furthermore, with these measures, an improved filtration aid action is achieved with the supply of controlled grounded calcium carbonate particles. Equally, a lower consumption of lime and stable quality are possible, with a lower CO 2 impact.

[0035] The production lead time can be reduced. The slaking process requires a lower maturation retention time because of an optimized calcination of the limestone.

[0036] Likewise, the measures of the invention improve the CaO usage in the process, as up to 70%, preferably up to 30% of quicklime (CaO) can be replaced by an equivalent weight of calcium carbonated (CaCOs) without impacting negatively the filtration efficacy. This reduction causes a reduction in the raw geological material usage, a reduction of fuel consumption, and a reduction of CO 2 emissions.

[0037] Moreover, these measures require few or no modification in the existing hardware of an existing sugar beet juice purification process and allow a better filtration (e.g. less clogging).

[0038] Advantageously, the sludge generated in the filtration is a valuable product that can be easily recycled in several applications such as agricultural purpose or as a CaCO 3 source for CaO production.

[0039] Furthermore, the measures of the invention may simplify the purification process by reducing or eliminating certain wastes on site such as limestone fines, fuel rests, water treatment residues, overburnt and unburnt materials resulting from the slaking process. In other words, the preparation of the quicklime is handed over to lime producers that can ensure high quality quicklime through controlled processes (e.g., calcination in parallel flow regenerative kiln) with a low CO 2 emission (possibility to capture or sequester CO 2 ).

[0040] The kit or the particle mixture described above or a milk of lime produced with said kit or the particle mixture can be used for CO 2 capture in air or in flue gas.Brief Description of Drawings

[0041] Aspects of the invention will now be described in more detail with reference to the appended drawings, wherein same references illustrate same features. Figure 1 depicts a purification process of raw sugar juice according to the state of the art. Figure 2 represents a purification process of raw sugar juice according to the invention. Detailed description

[0042] The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may however be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness.

[0043] Figure 1 depicts a purification process of raw sugar juice, in particular beet juice, according to the state of the art. The steps of this process are described in the background art section of the present disclosure.

[0044] Figure 2 illustrates a purification process of raw sugar juice, in particular beet juice, according to the invention. Compared to the purification process of Figure 1, the quicklime production unit in step S1 and the milk of lime production and filtration stages in step S2 are replaced by a step of supplying an adapted composition as a mix or a combination of two compositions (step S1') and a simplified slaking process (step S2') in order to produce a milk of lime formed with a calcium containing absorbent composition according to the invention. The two compositions can be mixed before the mixture is contacted with water or desweetening juice during the slaking process for forming the milk of lime MOL'. Alternatively, the two compositions can be added separately to the water or desweetening juice for forming the milk of lime MOL'. The slaking process is simplified in terms of needs for filtering and size of the installation. As the particles used for the process fulfilled certain quality standards, no further screening and filtering are needed, thereby eliminating certain waste streams. The source of CO 2 produced in Step S1 and then used in Step S5 and Step S7 is replaced by another source of CO 2 , for instance a CO 2 source available inside the plant where the purification process of raw sugar takes place. The other source of CO 2 is then used in step S5' and step S7' as discussed below. Compared to Figure 1, Figure 2 shows a slaking process performed in batches. The preparation of the milk of lime MOL' in batches allows an accurate and ponderal dosage. Even if the use of a batch process is preferable, a continuous slaking process can be also used as an alternative to or in combination with the batch process.

[0045] As for the purification process of raw sugar juice of Figure 1, the milk of lime MOL' in Figure 2, is mixed with the raw juice in the prelimer in Step S3' to increase smoothly the pH to a pH comprised in the range 8.5 to 11.5 (measured at 20°C) and to initiate several chemical reactions producing precipitation, flocculation of several non-sugar compounds present in the raw juice. It has been discovered that during the contacting of the milk of lime MOL' with the raw juice, a portion of the alkaline earth carbonates (e.g. CaCO 3 ) particles present in the milk of lime MOL', dissolves in said juice because of its low pH value (below 7), besides the further dilution induced by the injection of given volume of milk of lime MOL' in a comparatively large volume of raw juice. In other words, the alkaline earth carbonates are used not only as a filter aid but also to induce an indirect pH increase due to its dissolution.

[0046] The pre-limed juice is then mixed with a second amount of milk of lime MOL' in the main limer in Step S4'. Optionally, as for the known purification process of raw sugar juice of Figure 1, an intermediate cold liming step (not illustrated in Figure 2) takes place before the (hot) main liming in step S4'.

[0047] After main liming in step S4', the limed juice enters the carbonation vessel(s) in Step S5' where CO 2 is injected causing the carbonation of the lime solution, leading to the formation (nucleation and growth) of carbonated lime. CO 2 injection causes a pH reduction of the limed juice. This carbonation step (CO 2 reaction and pH reduction) induces a precipitation, coagulation and flocculation of the particles in the intermediate juice.

[0048] The (solid) particles of intermediate juice are filtered or decanted in the filtration stage in step S6', where the precipitated alkaline earth carbonate (e.g. CaCOs), and non-sugar components and impurities are separated from the aqueous suspension (intermediate juice).

[0049] Preferably, a second carbonation stage in step S7' and a second filtration stage in Step S8' occur to further remove remaining impurities to reach a sufficiently purified sugar juice before evaporation and crystallization.

[0050] One embodiment according to the process illustrated in Figure 2, is further detailed. The system for purifying an aqueous composition that comprises or consists of a first particle composition, in particular quicklime particles, and a second particle composition, in particular alkaline earth metal carbonate (e.g. CaCO 3 ) particles, is provided in step S1'. The weight fraction of said first composition relative to the weight of said system is greater than 30%, preferably greater than 50%, in particular greater than 70%. The weight fraction of the second composition relative to the weight of said system is greater than 15%, preferably greater than 30%, in particular greater than 40% but less than 70%.First particle composition (quicklime) characteristics

[0051] The first particle composition has a CaO content of at least 70%, preferably at least 80% in weight, more preferably at least 90% in weight. The first particle composition preferably has a d 99 lower than 2 mm, preferably such as measured by sieve analysis.

[0052] Several parameters of the first particle composition are characterized.

[0053] The particle size distribution is preferably measured by sieve analysis. The sieve analysis is an analysis technique known in the field, and uses sieves with different mesh sizes to determine the weight fraction of the initial weight of the test sample that is passing the sieve with a given mesh size. The sieving can be performed by means of vibrating sieves, wherein the sieve vibrating is controlled by the equipment used. Alternatively, the sieving may be performed manually. Components of the test sample that pass through a sieve with a certain mesh size have at least two dimensions that is smaller than the mesh size of a reference sieve. The mesh sizes used in the reference sieve analysis depend on the expected dimensions of the particles under investigation. The result is the cumulative particle size distribution. The d 99 is expressed in metric unit (µm) and means that 99% of the sample in weight has a size equal or below this reference d 99 .

[0054] The reactivity of the first particle composition is characterized by t 60 that it is the time to reach 60°C when 150 g of product, crushed below 5 mm, is added to 600 mL of water (20°C), according to EN459-2.

[0055] The CaO content is measured with the CaO available measurement according the EN459-2. The available CaO content is determined using the quantity of acid consumed during a "controlled" reaction, in which the OH -< ions released during the dispersion of quicklime and hydrated lime products in a sugar containing water are neutralized.Second particle composition (alkaline earth metal carbonate) characteristics

[0056] The second particle composition has a CaCO 3 content or a CaCO 3 and MgCO 3 content of at least 90% in weight, preferably at least 95% of CaCO 3 in weight, preferably at least 97% in weight, in particular around 99% of CaCO 3 in weight, a d 10 greater than 0.8 µm, preferably such as measured by laser diffraction analysis, a d 50 greater than 2 µm, preferably such as measured by laser diffraction analysis, optionally a d 99 lower than 2 mm, preferably such as measured by sieve analysis, and a Carr's (compressibility) index lower than 50%.

[0057] CaCO 3 content in weight percent is measured from a calculation:         CaCO 3 = 100 - Al 2 O 3 - Fe 2 O 3 - SiO 2 - Mn 3 O 4 - S * 2.497 - MgCO 3 - 0.3 Where Al 2 O 3 , Fe 2 O 3 , SiO 2 , Mn 3 O 4 and MgO are expressed in weight percent. These impurities are estimated by X-ray fluorescence. When the MgCO 3 content is lower than 5% in weight, XRF analysis can be used to determine the amount of MgCO 3 . As the XRF measurements are expressed under the MgO equivalent form, the MgCO 3 calculated using the atomic mass ratio, namely MgCO 3 percent in weight being equal to MgO percent in weight measured times 2.082. When the MgCO 3 content is higher or equal to 5% in weight, a Mg EDTA determination method is used. First, an acid reaction is performed with HCl 30% in weight to release all Ca and Mg from compound sensible to acid in the solution. Then, a Ca / Mg complexing agent EDTA (Ethylenediaminetetraacetic acid) is gradually added. A Ca / Mg specific electrode is used to detect the equivalent point where no more Ca 2+< and Mg 2+< ions are available (all complexed by EDTA). By this way, Ca 2+< + Mg 2+< are determined. A second titration is then performed where a specific Mg 2+< sequestrant agent is added to a new sample. Then a titration with EDTA is performed to evaluate the amount of Ca 2+< ions in the new sample. The difference between the 2 titrations allows to determine the amount of Mg 2+< ions. The Mg percent in weight is so first evaluated with a sample. The MgCO 3 percent in weight is equal to Mg percent in weight times 3.47.

[0058] Several parameters of the second particle composition are characterized.

[0059] The particle size distribution (PSD) of the second particle composition is measured with a laser diffraction particle size analyzer (e.g. Sympatec Helos / BR multiranges with a wet dispersion - water for alkaline earth metal carbonate - Quixel equipment using ultrasound). If this analysis is used for quicklime, methanol is used as solvent for this analysis. The result is a volume or weight cumulative curve between 0.5 to 350 µm. From this curve is defined the d 10 and d 50 : d 10 is the size of the particle for which 10% in weight of the particles have a size equal to or lower than the d 10 ; d 50 is the size of the particle for which 50% in weight of the particles have a size equal to or lower than the d 50 . Measurement in performed in volume but could be used in weight with hypothesis of the same particle density:vol%=vol / totalvol*100=weight / particledensity / totalweight / particledensity*100=weight / totalweight*100=weight%

[0060] As for the d 99 of the first particle composition, the d 99 of the second particle composition is determined with sieves. The result is the cumulative particle size distribution. The d 99 is expressed in metric unit (µm) and means that 99% of the sample in weight has a size equal or below this reference d 99 .

[0061] The bulk density (ρ B ) is the density calculated from the weight of particles that fill a given volume, for example 300 cm 3< . The bulk density is measured according to ASTM D5004, performing the measurement three times and calculating the average bulk density.

[0062] The tapped density (ρ T ) according to ISO787 (part 11) defines a density of tapped particles. For this purpose, a known amount / weight of particles is put in a graduated recipient. Then, 1250 chocks are applied with an automatic vibrating table. The determination of the volume allows to determine the tapped density.

[0063] The particle compressibility is defined by the Carr's index (C) calculated as follows: C = 100 % 1 − ρ B ρ T . Carr's index is used in the present disclosure to express the particles compressibility and the cohesion. The lower the ratio is the lower the compressibility is.

[0064] The textural characteristics are defined surface BET (S BET ) and the porous volume (Vp).

[0065] The surface BET and porous volume are determined with N 2 adsorption-desorption isotherm measurement, performed e.g. in a TriStar II 3020 from Micromeritics, where N 2 is slowly injected during the measurement and measured, by pressure, the amount that it is adsorbed. The surface area is estimated by applying the BET (Brunauer, Emmett et Teller) theory on the isotherm. It covers micropores and mesopores (pore diameter range between 0 and 50 nm). The porous volume, or Vp single point, is the amount of adsorbed N 2 when P / P 0 is equal to 0.98 (pore diameter range from 2 to 100 nm).

[0066] In step S1' of Figure 2, the first and second particle compositions can be supplied separately and then mixed on site, or alternatively a mixture of said first and second compositions can be supplied on site. The mixture is then contacted with a water-based liquid to form a milk of lime MOL'. Alternatively, the milk of lime can be prepared with first and second particle compositions added separately. Advantageously, the water-based liquid used for the slaking is a water used to clean filtrated sludges generated during a sugar beets purification process, in particular an aqueous solution that has been used to wash the sludges formed in the filtration process in steps S6' and S8'. The milk of lime MOL' has a pH in the range 9.5-11.5 and a temperature range between 15 to 80°C, preferably around 42°C. Preferably, the milk of lime MOL' after contacting said first and second compositions with the water based liquid has a viscosity lower than 1500 cP and preferably below 300 cP at 20°C (dynamic viscosity measured with a rotational viscosimeter, e.g. Anton Paar ViscoQC ™< 100, or a rheometer, at a shear rate of 5 s -1< with a concentric cylinder spindle - 65 mm height ad 18 mm diameter - according to DIN 53019). The content of Ca(OH) 2 typically is comprised in the range 170 to 660 g / l, in particular 190 g / l. The dry matter can be evaluated. It represents the CaO under Ca(OH) 2 and alkaline metal earth carbonate but also the solid content of the desweetening juice. It is measured by heating 10 g of MOL with an IR thermobalance at 150°C.

[0067] As the reactivity of the quicklime present in the first particle composition is advantageously predefined via t 60 , it is possible to control the heat release during the slaking process and therefore optimize the heat recovery, especially via the extraction of the heat of the milk of lime MOL' produced. As the process lead time for forming the milk of lime MOL' (residence time of the products in the slaking vessel) is considerably reduced with the measures of the present invention, there are fewer uncontrolled heat losses via the slaking vessel walls. Instead of recovering heat in the steam, the walls of the hydrator can comprise heat exchanger to absorb the heat generated during the slaking.

[0068] As the particle size of the first and second particle compositions are precisely controlled, a filtering of the milk of lime MOL' is not required, further enhancing the efficacy of the process according to the present invention.

[0069] A portion of the milk of lime MOL' produced is used for the preliming step S3' where the milk of lime MOL' is injected steadily in a raw sugar beet juice stream. Typically, the raw juice typically has a pH (measured at 20°C as 20°C is the reference temperature) between 5.9 and 6.5 and a temperature between 68 to 75°C, in particular 72°C. The milk of lime MOL' is injected in the raw juice to reach a pH (standardized at 20°C) between 8.5 to 12, in particular 11.4.

[0070] Another portion of the milk of lime MOL' produced is used for the main liming in step S4'. Before the main liming stage, the prelimed juice is heated to a temperature preferably between 80 and 90°C, in particular 83°C. The total amount Ca(OH) 2 coming from the quicklime injected during the preliming and liming stages typically corresponds to an equivalent of CaO comprised in the range 1.8 to 12 g / l, in particular 9.5 g / l. The pH (as standardized at 20°C) is controlled, preferably in the range from 11 to 13, preferably 12.5. CaO is measured by a titration with a concentrated HCl solution (e.g. 1 N).

[0071] A first carbonation in step S5' consisting of introducing CO 2 into the limed juice, leading to a carbonated limed juice, is performed at a temperature between 80 and 90°C, preferably 85°C, to decrease the pH (as measured at 20°C, as 20°C is the reference temperature) to a target between 9 to 12, preferably 11.2 at 20°C.

[0072] A first filtering and decantation step (S6') consisting of removing particles in suspension in the carbonated limed juice takes place.

[0073] A second carbonation step S7' consisting of introducing CO 2 into the filtered juice, leading to a further carbonated limed juice, is performed at a temperature between 85 and 100°C, preferably 92°C, to decrease the pH to a target between 7.5 and 9.8 (measured at 20°C), in particular 9.2.

[0074] A second filtering and / or decanting step (S8') consisting of or comprising removing particles in suspension in the limed juice or carbonated limed juice is performed.

[0075] To illustrate the invention, various compositions are assessed. Manipulations are carried out to reproduce a sugar juice purification process in a laboratory configuration. For this purpose, several mixtures of quicklime (t 60 = 114 sec, d 99 = 70 µm, CaO = 90.3%) and the second particle composition are prepared. Their characteristics are illustrated in table 1. For each preparation, a MOL' is prepared by adding 115 g of product, namely mixed mixture of quicklime and alkaline earth metal carbonate, with a rate of 11.5 g / min to 800 ml desweetening juice coming from a sugar beets purification plant, said juice having a pH between 9.5 and11.5, a dry matter at 150°C ranging from 10 to 16 % in weight, Ca EDTA below 1400 mg / l and a temperature of 42°C. Each preparation leads to a MOL' with a viscosity < 150 cP at 25°C (a pause of 15 minutes is foreseen after all the material additions, before the resulting MOL' is used).

[0076] For the preliming, the milk of lime MOL' is added with a rate of 1 ml / min in 850 ml of raw juice with a pH from 5.9 to 6.5 and a temperature of 72°C to reach a pH 10.5. The volume used for the preliming is measured and is defined as Vpre. (a pause of 10 minutes is foreseen after all the milk of lime MOL' addition before the liming stage). The raw juice is a juice taken from a sugar beets plant and presents a density of 0.8 kg / l.

[0077] For the main liming, the prelimed juice is heated to T = 83°C before adding the milk of lime MOL' with a volume VMOL= [60 - Vpre] ml (a pause of 20 minutes is foreseen before the next step).

[0078] Before the first carbonation step, an anti-foaming agent: Breviol D107KP is added to limed juice. Then, the limed juice is heated to a temperature of 85°C. A pure CO 2 composition (100% by volume from Nippon Gas) is injected in the limed juice at a rate of 100 ml / min (25°C and 1.6 bar). A spreading system is used to have a homogeneous distribution. The first carbonation step has a pH target of 9.9 (measured at 85°C).

[0079] Then, a first filtration by gravity takes place using a paper filter (filter paper - Wet strengthened qualitative - 16.5 cm - 91 - 10 µm - Cytiva - Whatman). The liquid filtered is designated JC1.

[0080] For the second carbonation step, the filtered liquid JC1 is heated to a temperature of 92°C. Then, a pure CO 2 composition (100% by volume from Nippon Gas) is injected in the limed juice at a rate of 100 ml / min (25° and 1.6 bar). A spreading system is used to have a homogeneous distribution. The second carbonation has a pH target of 8.1 (measured at 92°C).

[0081] Then, a second filtration by gravity takes place using a paper filter (Filter paper - Wet strengthened qualitative - 16.5 cm - 91 - 10 µm - Cytiva - Whatman). The liquid filtered is designated JC2.

[0082] The first and second juice treatment efficiencies are characterized by the absorbance measurement and Ca content of the first clear juice JC1 and second clear juice JC2, respectively. Analyses are performed on a juice kept in a fridge. Analysis is performed at the latest 24 h after production. Two parameters of the juice are determined: Juice color (Absorbance) and Ca content (Ca EDTA).

[0083] The absorbance test allows to determine the content of remaining impurities in the filtered juice. The absorbance is measured as recommended by I.C.U.M.S.A. method. The absorbance measurements at 420 nm with a UV-Vis spectrophotometer. A clear juice is sought to comply with the manufacturing specifications.

[0084] The Ca EDTA test allows to determine the content of Ca in the filtered juice. An excessive level would cause damage to the production installations, especially during the evaporation phase of the filtered juice. Moreover, residual calcium means an inefficient use of the Ca source, meaning CaO or CaCO 3 .

[0085] The Ca content is defined through a Ca EDTA titration. First, an acid reaction is performed with HCl 30% in weight to release all Ca from compound sensible to acid in the solution. Then, a Ca complexing agent EDTA (Ethylenediaminetetraacetic acid) is gradually added. A Ca / Mg specific electrode is used to detect the equivalent point where no more Ca 2+< ions are available (all complexed by EDTA). When Mg 2+< is present, it is possible also to evaluate the amount at the same time than Ca 2+< (see above).Examples

[0086] Seven product compositions are evaluated having the following characteristics: TABLE 1 (Second particle composition)SampleCaCO 3 contentd 10 (µm)d 50 (µm)bulk density (kg / l)tapped density (kg / l)Carr's Index (%)S-BET (m 2< / g)Vp (cm 3< / g)197.9920.4876.621.271.8230.20.590.002298.721.156.970.851.5645.51.390.005398.450.812.260.561.149.12.210.005498.461.075.470.811.5146.41.830.0065--------698.690.691.440.490.9246.77.370.02798.841.238.220.952.0553.71.120.004 TABLE 2 (Compositions and results) Sample1 st< particle composition (weight %)2 nd< particle composition (weight %)JC1 absorbanceJC1 - Ca EDTA mg / LJC2 absorbanceJC2 - Ca EDTA mg / LJC absorbance average mg / LJC - Ca EDTA average mg / L170300.57480.445960.47672270300.566180.493860.53502370300.757100.54340.63572440600.697710.574140.63593510000.759060.584370.67672670300.878550.615940.74725770301.3413701.259441.301157

[0087] Samples N° 1 to 4 are examples that improve the juice purification process as the absorbance of the clear juices JC1 and JC2 are at least decreased compared to the reference sample N° 5 where no filter aid in the form of alkaline earth metal carbonates is introduced. To compare the sample, the average of the JC1 Absorbance and the JC2 Absorbance, as well as the average of the JC1 - Ca EDTA and the average of the JC2 - Ca EDTA is taken into account. By using the average, a win on first filtration and / or second filtration could be compared with only one parameter.

[0088] Samples N° 6 to 7 define comparative examples.

[0089] Sample N° 6 highlights that the presence of a high fines amount (with a diameter d 10 bellow 0.8 µm) deteriorates the efficacy of the purification treatment as these fines tend to clog the small pores of the filtering elements, leading to a reduction of the flow to be washed.

[0090] Sample N° 7 shows that the Carr's index plays a role in the filtration efficiency. Indeed, a filtered layer composed of a bed of alkaline earth carbonate materials are formed over a filter element. Said layer takes over the filtration process that was initiated by the filter element. The formation of the filtering layers is critical. A filtered layer that can be easily compacted under the filtering pressure leads to filter clogging. It has been discovered that alkaline earth metal carbonate particles with a Carr's (compressibility) index inferior to 50% leads to an improved filtering and therefore a clearer filtered juice because they are less incline to compaction and structural heterogeneity.

[0091] The Carr's index is dependent on the ratio between a tapped density and bulk density, and it allows to qualify the compaction ability of a particle matter and the formation of a heterogenous filter bed (a.k.a. filtered layer). In another words, the Carr's index allows to evaluate how a filter bed formed with particles could be cohesive / compacted. A bed that is too compacted will not be able to fully utilize the filtration potential. Indeed, the filtration is reduced as the liquid takes preferential paths. Conversely, a bed whose compaction is controlled will allow for the optimal utilization of the entire filtering volume through a network of distributed passages. The higher the Carr's (compressibility) index, the higher the particle matter is cohesive, inducing a more compacted bed. A combination of small particles and large particles tend to form cohesive layer as the small particles tend to occupy the spaces left by the large particles. Therefore, the Carr's index is at least linked to the particle size distribution of the particles forming the filter bed.

[0092] Besides the Carr's index, an important parameter of the particle size distribution curve to considered is the d 50 , for instance of at least 2 µm. This parameter prevents a too narrow distribution in the fine section. Furthermore, the alkaline earth metal carbonate particles serve as a nucleation source and their predefined particle size distribution is used to control the separation of several non-sugar compounds present in the raw juice, the limed juice and the carbonated juice. In this context, a too small d 50 reduces the control of the size of the precipitate particles. On the other side, d 50 should not be too high (preferably lower than 60 µm, more preferably lower than 30 µm, in particular lower than 25 µm). Indeed, the external porosity of the particles is reduced with the increase of the d 50 , leading to a lower score in terms of Ca-EDTA.

[0093] Furthermore, a low d 50 improves the dissolution of CaCO 3 . The dissolution of a portion of CaCO 3 is sought, so that the CaCO 3 acts as a substitute to the CaO in the solution. The solubility of the CaCO 3 in a neutral aqueous solution is small but the solubility of the CaCO 3 can be increased in an acid aqueous solution. The raw juice, in which the milk of lime MOL' is injected, is a typical acid solution. Therefore, the acid nature of the raw juice would favor the dissolution of some of the CaCO 3 present in the milk of lime MOL'. Therefore, there is an optimum in the particle size distribution. Too small alkaline earth metal carbonate particles (e.g. CaCO 3 ) would enhance the efficiency of the alkaline earth metal carbonate (e.g. CaCO 3 ) as a substitute for the alkaline earth metal oxide (e.g. CaO) at the cost of a lower filtration capability and separation capability. To the contrary, larger alkaline earth metal carbonate (e.g. CaCO 3 ) particles would enhance the filtration and separation capability at the cost of an efficient substitution of alkaline earth metal oxide (e.g. CaO) by the alkaline earth metal carbonate (e.g. CaCO 3 ).

[0094] The top cut is also important to be compatible for blending with the lime. The maximum size of the first composition should be comparable to that of the second particle composition.

[0095] A second particle composition with a high surface area allows to absorb the impurities of a certain size. Advantageously, porous particles implying a high specific surface BET and a high porous volume Vp tend to form rapidly a bed to ensure filtering, if these particles are not too small. However, the specific surface BET should not be too high otherwise the particles are not dense enough to ensure the formation of an effective filter bed. Advantageously a specific surface BET higher than 0.5 m 2< / g but lower than 3 m 2< / g and / or a porous volume higher than or equal to 0.002 cm 3< / g but lower than 0.01 cm 3< / g can be selected.

[0096] Thanks to the measures of the invention, samples N°1 to 3 and sample N°4 allow to substitute 30% and 40% by weight, respectively, of the quicklime while having the same efficacy as the reference composition according to Sample N°5. This substitution allows to reduce the CaO consumption, and the associated CO 2 emission produced during the calcination.

[0097] The present invention preferably relies on a milled quicklime forming the first particle composition that allows a better control of the grit formation and dissolution rate. The quicklime reactivity directly impacts the milk of lime MOL' properties. To obtain a proper particle size distribution in the milk of lime MOL', the reactivity of the quicklime source must be controlled. In addition, when the quicklime presents a t 60 that is too high, the lime slaking could take more time reducing the production efficacy. The examples N°1 to N°4 show that a satisfactory result can be reached with a 30% or 60% substitution. An optimum must be found in the lime substitution. The higher the ratio, the more economical it becomes because quicklime is more expensive to produce than calcium carbonate. A CaO source is still necessary in the purification process. In other words, the alternate source of Ca cations (CaCO 3 ) cannot compensate entirely the CaO. A substitution of CaO by CaCO 3 can be increased to 80% by weight. However, approaching the 60% conversion a lower purification is expected. A lower purification observed with a higher substitution rate can however be accepted for certain markets if costs are considered.

[0098] Contrary to usual filter aids that can be used, CaCO 3 is the best candidate. Indeed, first, a part could be dissolved and substitute CaO. Second, the compatibility with the sugar process is warrantied as the CaCO 3 is already used / produced in this process. Another advantage is the lower cost of CaCO 3 compared to organic additive or other inorganic filter aids such as zeolite. Finally, from a process and handling point of view, the blending of quicklime and second particle composition is easier. Fresh CaCO 3 has the advantage to not bring too much impurities compared to recycled sludges.

[0099] CaCO 3 used does not require to present certain crystallographic properties. Preferably, the crystalline CaCO 3 part is in the form of aragonite and / or calcite, wherein the content of aragonite and / or calcite is higher than 95.5%, preferably more than 99%, relative to the CaCO 3 in its crystallized form. The amorphous part of CaCO 3 is generally comprised in the range 5-10% by weight relative to the CaCO 3 content.

[0100] The first and second particle compositions must comply with food processing aid regulations. Moreover, it is mandatory to avoid interference in the sugar process as deposit on the filter, scale in the evaporator, abrasiveness, equipment clogging induced by the major impurities. The main impurities of the second particle composition are (expressed under oxide form) Mn 3 O 4 , Al 2 O 3 , Fe 3 O 4 , SiO 2 .

[0101] In the present disclosure, the term limestone should be understood as encompassing dolomitic limestone or dolomite. Equally, the term quicklime should be understood as encompassing dolomitic quicklime and burnt dolime.

[0102] By burnt dolime or dolomite is meant a dolomitic quicklime or dolomitic limestone composition respectively, in which the amount of Mg in moles is substantially equal to the amount in moles of Ca.

[0103] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.

[0104] The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention may be practiced in many ways, and is therefore not limited to the embodiments disclosed. It should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to include any specific characteristics of the features or aspects of the invention with which that terminology is associated.

Claims

1. Kit for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets, said kit comprising or consist in: - a first particle composition having quicklime, wherein the weight fraction of said first composition relative to the weight of said kit is greater than 30%, preferably greater than 50%, in particular greater than 70% and wherein the first particle composition has a CaO content of at least 70% in weight, preferably at least 80% in weight, in particular at least 90% in weight relative to said first composition, and optionally a d99 lower than 2 mm, preferably such as measured by sieve analysis; and - a second particle composition having a CaCO3 content or a CaCO3 and MgCO3 content of at least 90% in weight, in particular at least 95% in weight, preferably at least 97% in weight relative to said second composition, a d10 greater than 0.8 µm, preferably such as measured by laser diffraction analysis, and a d50 greater than 2 µm, preferably such as measured by laser diffraction analysis and a Carr's index lower than 50%, and optionally a d99 lower than 2 mm, preferably such as measured by sieve analysis, , wherein the weight fraction of said second composition relative to the weight of said kit is greater than 15%, preferably greater than 30%, in particular greater than 40%, but less than 70%.

2. The kit according to Claim 1, wherein the first particle composition has a t60 lower than 10 minutes, preferably lower than 8 minutes, more preferably lower than 5 minutes, in particular lower than 2 minutes.

3. The kit according to Claim 1 or 2, wherein the d50 of the second particle composition is lower than 60 µm, preferably lower than 30 µm, in particular lower than 25 µm.

4. The kit according to any of the preceding claims, wherein the second particle composition has a specific surface BET higher than 0.5 m2 / g but lower than 3 m2 / g and / or a porous volume higher than or equal to 0.002 cm3 / g but lower than 0.01 cm3 / g.

5. The kit according to any of the preceding claims, wherein the cumulative content of Mn3O4, Al2O3, Fe3O4 and SiO2 is less than 5%, preferably less than 4%, preferably less than 3% by weight relative to the second particle composition.

6. The kit according to any of the preceding claims, wherein the second particle composition has a MgCO3 content of less than 10% by weight relative to second particle composition.

7. The kit according to any of the preceding claims, wherein the kit is in the form of a ready-to-use particle composition, the ready-to-use particle composition comprising or consisting of a mixed particle composition of the first and second particle compositions.

8. A process for treating, in particular purifying, an aqueous composition comprising saccharose, comprising: a) contacting the kit according to any of the preceding claims with an aqueous solution, thereby forming a milk of lime (MOL') and generating heat; b) alkalizing and nucleating the aqueous composition by adding a first portion of said milk of lime, to a pH ranging from 8.5 to 11.4, leading to a pre-limed juice, preferably said pH being measured at 20°C; c) further alkalizing and nucleating the pre-limed juice by adding a second portion of said milk of lime, to a pH ranging from 11.0 to 13.0, leading to a limed juice, preferably said pH being measured at 20°C; d) at least one carbonation step consisting of or comprising introducing carbon dioxide into the limed juice, leading to a carbonated limed juice, and e) at least one of filtering and / or decantation step consisting of or comprising removing particles in suspension in the limed juice or carbonated limed juice.

9. The process according to the preceding claim, wherein the aqueous composition consists in or comprises a juice from sugar beets and wherein the aqueous composition comprises saccharose compounds and non-saccharose compounds.

10. The process according to Claim 8 or 9, wherein at least one of the first and / or second portion of the milk of lime is not filtered before being added to the aqueous composition and / or the pre-limed juice, respectively.

11. The process according to any of Claims 8 to 10, further comprising recovering the heat, in particular at least some heat in stream generated in step a).

12. The process according to any of Claims 8 to 11, preferably in combination with claim 9, wherein the milk of lime has a fraction of dry matters of at least 5% by but less than of 75%, preferably less than 50%, relative to the weight of said milk of lime, said dry matters comprising: - at least 37% but less than 94% of Ca(OH)2 by weight relative to said dry matters, and - at least 14% but less than 66% of CaCO3 or CaCO3 and MgCO3 by weight relative to said dry matters, and - optionally at least 2% but less than 30% of the saccharose and non-saccharose compounds, relative to said dry matters.

13. Use of a kit according to any of Claims 1 to 7, for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets.

14. A particle composition for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets, said composition having a CaCO3 content or a CaCO3 and MgCO3 content of at least 90% in weight, in particular at least 95% in weight, a d10 greater than 0.8 µm, preferably such as measured by laser diffraction analysis, a d50 greater than 2 µm, preferably such as measured by laser diffraction analysis, a d99 lower than 2 mm, preferably such as measured by sieve analysis, and Carr's index lower than 50%.

15. Use a particle composition according to the preceding claim for purifying an aqueous composition comprising saccharose, in particular a juice from sugar beets.

Images