Extra fine milk of lime

Abstract

Extra fine Milk of Lime The present invention relates to an extra fine milk of lime having superior flowability and pumpability, more particularly concerns a milk of lime comprising a dry solid content of fine lime particles higher or equal to 30 wt% and lower or equal to 70 wt% based on weight of the milk of lime, in aqueous phase, said milk of lime comprising at least a polymer dispersant at an amount of 01 to 2.0 wt% of active polymer dispersant relative to said total dry solid content of said milk of lime, and at least a stabilizer at an amount of 0.5 to 4.0 wt% of active stabilizer relative to said total dry solid content of said milk of lime. The present invention also relates to a process for manufacturing a milk of lime having a superior flowability and pumpability.

Description

[0001] Extra fine Milk of Lime

[0002] The present invention relates to an extra fine milk of lime having a superior flowability and pumpability. This milk of lime can be used for the treatment of water and / or sludge, neutralization of acidic waste, pH adjustment in chemical and nonferrous metal industries, paper and PCC industries, depolluting acid flue gases. Milk of lime can also be used in civil engineering, or in the building or agriculture sectors.

[0003] More particularly the present invention concerns a milk of lime comprising a dry solid content of fine lime particles higher or equal to 30 wt% and lower or equal to 70 wt% based on weight of the milk of lime, in aqueous phase, said milk of lime comprising at least a polymer dispersant at an amount of 0.1 to 2.0 wt% of active polymer dispersant relative to said total dry solid content of said milk of lime, and at least a stabilizer at an amount of 0.5 to 4.0 wt% of active stabilizer relative to said total dry solid content of said milk of lime.

[0004] The present invention also relates to a process for manufacturing a milk of lime having a superior flowability and pumpability.

[0005] High-reactive, concentrated, ready-to-use milk of lime or lime slurry (like Neutralac® SLS45) has become the reagent of choice for many applications in the aforementioned industries.

[0006] Next to the high reactivity, high solid content (higher or equal to 30 wt%) and improved rheological properties, the customers also appreciate a milk of lime with further improved rheological properties like a low viscosity, a low settling rate and an extended shelf-life, further improving said rheological properties.

[0007] Standard high solid content milks-of-lime produced either by slaking of quicklime or slurrying "dry" hydrated lime powder generally show a solid content typically below 50 wt%, for example between 30 and 40 wt%, a dissolution reactivity of 3 sec to 30 sec according to EN12485, but unfortunately, they have a viscosity around 300 mPa.s to 1500 mPa.s and settle within a day, thereby having a reduced shelf life.

[0008] Suspensions of 40 wt% or greater in solid content cannot be industrially produced by direct slaking of quicklime, as the exothermic reaction of quicklime slaking will let the suspension boil, creating thus highly unstable and even hazardous reaction conditions. Conventional cooling is typically not efficient to reduce the reaction temperature below the boiling point. Either the quicklime has to be partially pre-hydrated or the quicklime mixed with hydrated lime (either in the form of lime slurry or dry hydrate) to achieve >40 wt% solids content, see for example W02022 / 234008. In practice, this is rarely done due to the relative complexity of the process compared to slurrying.

[0009] Regarding slurrying dry hydrated lime to achieve 40 wt% solid content or greater, the viscosity of such suspensions tends to be quite high, aggravated by the shear thinning & thixotropic rheology of concentrated lime slurry. Additionally, the viscosity of lime slurry is typically instable, i.e. increasing over time. This effect can be so severe, that well-flowable lime slurry can turn into a thick paste within days or even just hours. It is known that the viscosity can be reduced by polymeric dispersants, typically polycarboxylate dispersants, especially polycarboxy late-ethers (PCE) dispersants, in which typically the polycarboxylate backbone is modified by polyether side chains, often in a comb co-polymer structure, see e.g. US2014 / 0140907.

[0010] However these dispersants typically do not prevent a viscosity increase to a paste-like state over time. For stabilizing viscosity over time, it is further known to add poly-alcohol additives, notably carbohydrates, including mono-, di-, oligo- and poly-saccharides, hydrogenated saccharides or sugar alcohols, sugar acids, e.g. so- called aldonic or uronic acids, such as e.g. gluconic acid or glucuronic acid, or their respective salts, or functionalized saccharides, such as N-acetyl-glucosamine or D- glucosamine, either alone, see e.g. W02007 / 1 1040, or in combination with a polycarboxylate dispersant, see e.g. W02006 / 050557 giving an additional benefit of reducing the viscosity.

[0011] Furthermore, it is known from the state of the art and particularly from document W02020 / 094607 that the combination of carbohydrate additive, notably sucrose, and a polycarboxylate polyether comb co-polymer dispersant such as certain Rheosperse dispersants available from CoatexSAS, can achieve low viscosity and limited viscosity increase over time, i.e. 14 days of storage under intermittent agitation (5min / h), even for milk of lime with low particle size.

[0012] Moreover, document W02022 / 234008 is also known from the state of the art and discloses a milk of lime having a low particle size with a combination of carbohydrate stabilizer and a polymer dispersant such as Chryso Neomere® Tech 646 for 45 wt% of solid content, this milk of lime can achieve a low viscosity around 45 mPa.s stable at 28 days (see Example 3). Unfortunately, the milk of lime disclosed in the prior art would benefit from improvement.

[0013] Indeed, calcium hydroxide slurries are characterized by their dry solid content (wt%) and fineness (fine particle size distribution under the notation dso and / or d9s). Increase in dry solid contents brings significant economic advantages, particularly in terms of transport and handling costs. Furthermore, the selection of the particle size distribution allows for several benefits in industrial applications (fast dissolution, higher effectiveness of certain industrial reactions).

[0014] As explained above, when the solids content and particle size distribution are selected / engineered, the viscosity of the slurry must be corrected using additives / stabilizers, because milks of lime are non-Newtonian fluids having variable viscosity dependent of stress. More precisely, calcium hydroxide slurries are shear-thinning or pseudoplastic fluids that can also exhibit thixotropy, especially at high solid contents and fine particle sizes. As clearly explained in cited documents, dispersants / additives / stabilizers improve the dispersion state of calcium hydroxide particles and induce a decrease in viscosity.

[0015] The shear thinning behavior imposes challenges in handling said milks of lime, as the higher viscosity (typically by a factor of magnitude xlO) in the resting state forces users / customers / manipulators to either maintain constant agitation in storage containers and constant circulation in dosing and distribution lines or face very high resistance, when restarting said agitation or circulation. This leads to significantly increased power consumption, over-dimensioned and thus more costly pumps, agitation motors and similar equipment. Despite the high viscosity at the resting state, the suspension is still susceptible to settle generally within a day, forming sedimentary deposits of increased solid content and resultingly also increased viscosity. The shear thinning nature will further increase the viscosity of such sediments at resting state, leading to pasty sediments and deposits in poorly agitated sections of transport or storage containers or piping or similar equipment. Such thickened deposits impede operation, leading to reduce flow rates from or even complete blocking of dosing and transfer lines as well as outlets of said transport and storage containers. Unfortunately, cleaning and / or removal of said deposits and settlings is typically onerous, requires special equipment and incurs notable costs, what needs to be improved.

[0016] Additionally, this non-Newtonian rheology provides notable challenges to the operators of storage and dosing installations. For example, milks of lime might very often (in a typical storage tank with the stirrer's impeller positioned close to the bottom outlet) not show any movement on the surface of the milk of lime during agitation. It is thus often difficult to impossible to homogenize the whole tank volume by agitation or even to evaluate visually, whether the agitation is sufficient to fluidize the milk of lime for distribution from the tank and for dosing into the application.

[0017] Another challenge to be solved is the pumping of the milk of lime from said storage tank. As the product will be massively reduced in viscosity by the shearing action of the pump, the viscosity of the milk of lime in the pump and at its outlet will be much lower than the one at the inlet. This can lead to the milk of lime exiting the pump at a faster rate than it is entering, risking cavitation and damage to the pump.

[0018] A conventional solution, as provided in state of the art, might seem to add copious amounts of additives / dispersants / stabilizers to reduce viscosity to water / cow milk-like fluidity, but this would also decrease the viscosity at the resting state. As such a low viscosity would massively facilitate and accelerate settling, such a product becomes unmanageable, as it becomes challenging to keep the particles in suspension.

[0019] The other extreme solution would be to add only very little dispersant or possibly only a viscosity stabilizer to reduce settling by accepting a very high viscosity at a resting state. Evidently, this high viscosity, even reduced under agitation or under circulation makes such products problematic to dose and pump, generate pasty and difficulties to remove deposits and thus in general difficulties to handling.

[0020] There is therefore a need to provide a milk of lime which endeavors to solve at least a part of these drawbacks.

[0021] There is a need to provide a milk of lime which manages to combine two contradictory and absolutely opposite worlds as abovementioned, namely a milk of lime having : a slow settling at resting state corresponding to a high viscosity at resting state, i.e. a high stress / force is required to transition the product from a solid-like resting state to a flowing (fluid) state, and a low, preferably very low, viscosity under stress, i.e. agitation or flow. Moreover, there is o need to provide o milk of lime having reduction or elimination of settling to reduce the inhomogeneity of the slurry under extended storage and avoid thickened, difficult to disperse sediment deposits.

[0022] Finally, there is a need to provide a milk of lime which facilitates manipulation, storage, pumping, dosing as well as the emptying and cleaning of tanks and lines, in order to save time and costs in processes using said milk of lime.

[0023] To solve these problems, it is provided according to the present invention, a milk of lime as previously presented, wherein said fine lime particles of said milk of lime having a particle size distribution with a characteristic diameter dso comprised between 1.0 and 3.5 m and d?8 lower than or equal to 15 pm as measured by laser diffraction (with a Beckman-Coulter LSI 3 320 equipment using methanol as carrier solvent and ultrasound sonication pretreatment 4min at 100W), and wherein said milk of lime having a viscosity above 2000 cP at 1 s-1shear rate and a viscosity lower than 200 cP at 100 S’1shear rate measured with a Anton Paar MCR102 Rheometer using cone & plate geometry at room temperature of ca. 20°C.

[0024] Measurements of particle size distribution according to the present invention are expressed in volume, for example dso is the diameter for which 50%vol of particles are smaller, d?o is the particle diameter for which 90%vol are smaller.

[0025] According to the present invention, Anton Paar MCR102 Rheometer is using cone & plate geometry.

[0026] In another embodiment of the present invention, the Anton Paar MCR102 Rheometer is using cup & cylinder geometry or cup & vane geometry.

[0027] Measurement of viscosity over a range of shear rates (i.e. from 1 s-1 to 100 s-1 ) are done with an Anton Paar MCR102 Rheometer using cone & plate geometry or cup & cylinder geometry or cup & vane geometry.

[0028] Measurement of viscosity at 100 rpm are done using a Brookfield DV-3 Rheometer with spindle 63 if viscosity is > 300 cP or with spindle 62 if viscosity is < 300 cP.

[0029] As can be seen, the milk of lime of the present invention is characterized by the combination of : its amount of dry solid content of fine lime particles higher or equal to 30 wt% and lower or equal to 70 wt% based on weight of the milk of lime, at least a polymer dispersant at an amount of 0.1 to 2.0 wt% of active polymer dispersant relative to said total dry solid content of said milk of lime, at least a stabilizer at an amount of 0.5 to 4.0 wt% of active stabilizer relative to said total dry solid content of said milk of lime, a particle size distribution with a characteristic diameter dso comprised between 1 .0 and 3.5 pm, a particle size distribution with a characteristic diameter d?8 lower than or equal to 15 pm, allowing according to the present invention to provide a milk of lime achieving a high viscosity at rest (above 2000 cP at 1 s-1shear rate), thereby reducing settling and a very low viscosity under stress (lower than 200 cP at 100 S’1shear rate).

[0030] In order to better understand how these contradictory and opposite features are met by the milk of lime according to the present invention, it is necessary to consider the following rheological model :

[0031] Every material can be considered to have elastic as well as viscous properties, meaning that a force exerted onto an elastic object would result in an elastic deformation, which is reversible as the deforming force is removed. A viscous material will start flowing under exertion of a force. The study of rheology finds that any fluid can be described by and thus attributed elastic as well as viscous properties, and that shear thinning fluids show a higher degree of elastic behavior at rest or at low force

[0032] Moreover, in rheology : the elastic properties of a fluid are quantified by the "Storage Modulus" G' (G prime), the viscous properties of a fluid are quantified by the "Loss Modulus" G" (G double prime).

[0033] Like the viscosity, G' and G" change with applied shear rate or shear force and in a conventional manner, if G' is significantly greater than G", a material will behave like solid (no sedimentation should occur as the fluid should be too stiff for particles to move). As shear force / deformation is applied, G' decreases in a shear thinning fluid as will G" . But, if G' decreases faster than G" , G" can become significantly greater than G', and the material fluidity increases, which is typically the case for many highly concentrated and fine lime slurries or milk of lime according to the prior art. In a particularly surprising manner, the inventors have succeeded, in the milk of lime according to the present invention and by the combination of the features presented above, in controlling the point where G' becomes equal to G" in order to provide the milk of lime of the invention having a low settling or even no settling with a low viscosity under moderate shear stress.

[0034] Advantageously the milk of lime of the present invention with the reduction or elimination of settling, reduces the inhomogeneity of the slurry under extended storage and avoids thickened, difficult to disperse sediment deposits, and the low, preferably very low, viscosity in the flowing state facilitates the pumping, dosing as well as the emptying and cleaning of tanks and lines.

[0035] Contrary to milk of limes provided in the state of the art, the milk of lime of the present invention stabilizes the viscosity overtime, but also the storage modulus G' and the loss modulus G", which result in increasing of the shelf-life and ease-of- use of the product.

[0036] Moreover, the present invention with said low, preferably very low, and more stable viscosity over time at different agitation and pumping rates, allows to eliminate or at very least reduce the risk of cavitation in pumps, the need of constant agitation in tanks or circulation in dosing and transfer lines and facilitate homogenization by tank agitation.

[0037] In a preferably and advantageous embodiment of the milk of lime of the present invention, the transition point of G" becoming equal to G1is at greater than 0,1% deformation and / or greater than 1 Pa shear force with G1being greater than 2x G" at some stage before the transition point as well as G" being greater than 2x G1at some stage after the transition point.

[0038] In other words, the present invention provides a milk of lime having an increased decrease, thus a faster transition from the stiff (solid-like) resting state to the liquid agitated one.

[0039] Furthermore, the milk of lime of the invention strongly reduce to largely eliminate the risk of formation of stiff sediment deposits, but as also the formation of clear supernatant is notably reduced, and the need for homogenization by mixing is massively reduced. This is especially beneficial and particularly advantageous, if a large number of containers (industrial bulk containers, IBCs or tanker trucks) are used for transport, for which homogenization would be labor intensive and challenging to perform due to an unfavorable geometry and / or lack of a suitable agitation equipment. In addition, the milk of lime of the present invention, in a particularly advantageous manner, allows to reduce the need for cleaning of tanks and lines of such deposits, resulting in significant time and costs savings.

[0040] In a preferred embodiment of the milk of lime according the present invention, said lime particles present a specific surface area < 12 m2 / g, preferably < 10 m2 / g, more preferably < 9 m2 / g, ideally < 8 m2 / g (as measured by a Micromeritics Tristar equipment using the BET nitrogen adsorption-desorption method as described in standard DIN 66134).

[0041] Indeed and in an preferably manner, obtaining said milk of lime according to the present invention comprising said advantageously features is difficult with lime particles presenting high specific surface area.

[0042] Furthermore, said lime particles according to the present invention are chosen presenting a specific surface area < 12 m2 / g, preferably < 10 m2 / g, more preferably < 9 m2 / g, ideally < 8 m2 / g.

[0043] The objective of the milk of lime of the present invention, with said specific lime particles with specific surface area is to limit interactions between neighboring particles, which are all the more important the higher the concentration. So, if the specific surface area is high, the particles can create more interactions because the surface area available for them to be created is greater, so it is intended to prefer to use lime particles with a low specific surface area such as.

[0044] Other embodiments of said milk of lime according to the invention are mentioned below.

[0045] Preferably, the milk of lime according to the present invention produces a decantation of less than 5 wt% bottom solid residues measured during 28 days, more preferably measured during 42 days, even more preferably measured during 56 days.

[0046] In a preferred embodiment, the milk of lime according to the present invention produces a decantation of less than 20 vol% supernatant measured during 28 days, more preferably measured during 42 days, even more preferably measured during 56 days.

[0047] In a particularly advantageous manner, the milk of lime of the present invention producing a decantation of less than 5 wt% bottom solid residues and / or of less than 20 vol% supernatant, stable over time during 28 days, preferably 42 days and even more preferably 56 days, allows to avoid the loss of flow rates in dosing and transfer lines as well as outlets, (transport and storage) and avoid or at very least reduce the cleaning, removal of such deposits.

[0048] Preferably, the fine lime particles of said milk of lime according to the present invention having a particle size distribution with a characteristic diameter d25 higher than or equal to 0.4 m when said characteristic diameter dsoof said fine lime particles of said milk of lime is higher than or equal to 1 .0 pm.

[0049] In an advantageous embodiment, the fine lime particles of said milk of lime according to the present invention having a particle size distribution with a characteristic diameter dso comprised between 1 .0 and 3.4 pm, preferably between 1.0 and 3.3 pm, more preferably between 1.0 and 3.2 pm, even more preferably between 1 .0 and 3.1 pm, in particular between 1 .1 and 3.0 pm, preferably between 1.2 and 3.0 pm, more preferably between 1.3 and 3.0 pm, even more preferably between 1.4 and 3.0 pm, advantageously between 1.5 and 3.0 pm, more advantageously between 1 .6 and 3.0 pm, even more advantageously between 1 .7 and 3.0 pm, in particular between 1 .8 and 3.0 pm, more particularly between 1 .9 and 3.0 pm, preferably between 2.0 and 3.0 pm, more preferably between 2.1 and 3.0 pm, even more preferably between 2.1 and 2.9 pm, in particular between 2.2 and 2.9 pm, advantageously between 2.2 and 2.8 pm, for example 2.3 pm, 2.4 pm, 2.5 pm, 2.6 pm, 2.7 pm.

[0050] More preferably, the fine lime particles of said milk of lime according to the present invention having a particle size distribution with a characteristic diameter d?8 lower than or equal to 14 pm, advantageously lower than or equal to 13 pm, preferably lower than or equal to 12 pm, more preferably lower than or equal 1 1 pm, even more preferably lower than or equal 10 pm.

[0051] Advantageously, the amount of solid content of fine lime particles in the milk of lime according to the present invention is higher or equal to 35 wt% and lower or equal to 65 wt%, preferably higher or equal to 40 wt% and lower or equal to 60 wt%, even more preferably higher or equal to 40 wt% and lower or equal to 55 wt%, advantageously higher or equal to 40 wt% and lower or equal to 50 wt%, for example 41 wt%, 42 wt%, 43 wt%, 44 wt%, 45 wt%, 46 wt%, 47 wt%, 48 wt%, 49 wt%.

[0052] Even more preferably, the at least one polymer dispersant in the milk of lime according to the present invention is a polycarboxylate polyether comb copolymer.

[0053] In a further embodiment, the at least one polymer dispersant in the milk of lime according to the present invention, preferably the polycarboxylate polyether comb copolymer, has a main chain containing (meth)acrylate units and lateral chains comprising oxyethylene or oxypropylene groups.

[0054] In another embodiment, it should be noted that the oxyethylene and oxypropylene groups of the copolymer side chains can be arranged randomly, on a regular basis or in a block. To be more precise, an example of polymer dispersant according to the present invention consists of methacrylic acid monomers and / or any of its salts, possibly of acrylic acid monomers and / or any of its salts, monomers with the formula (I) : R — X — R' according to which :

[0055] R represents a polymerizable unsaturated group, notably acrylate, methacrylate, methacrylurethane, vinyl or allyl,

[0056] R' represents hydrogen or an alkyl group with from 1 to 4 carbon atoms,

[0057] X represents a structure with "n" unit(s) of ethylene oxide EO and "m" unit(s) of propylene oxide PO, arranged randomly or regularly, "m" and "n" abovementioned are 2 non-zero integers and are between 1 and 150.

[0058] Thus, an example of dispersant copolymer according to the invention has a skeleton consisting of methacrylic acid monomers, and possibly acrylic acid monomers, preferably the dispersant copolymer has a skeleton consisting of methacrylic acid monomers exclusively or has a skeleton consisting of methacrylic acid monomers and acrylic acid monomers.

[0059] For example, a suitable polymer dispersant in the milk of lime according to the present invention is Rheosperse 4050 (Coatex SAS).

[0060] In another embodiment, examples of dispersant copolymer according to the invention are disclosed in document FR2776285 hereby incorporated by reference.

[0061] For example, a suitable polymer dispersant in the milk of lime according to the present invention is Neomere® Tech 646 (Chryso SAS).

[0062] Other examples of suitable polymer dispersant in the milk of lime according to the present invention are Neomere® Tech 757 and / or Neomere® Tech 868 (Chryso SAS) and / or dispersant from EPB1442049 (Chryso SAS).

[0063] Another further example of suitable polymer dispersant in the milk of lime according to the present invention is from Viscocrete family, more preferably Viscocrete 3027 (SIKA). In an advantageous embodiment of the milk of lime of the present invention, the at least stabilizer is present at an amount of 0.6 to 3.9 wt%, preferably at an amount of 0.7 to 3.8 wt%, more preferably at an amount of 0.8 to 3.7 wt%, even more preferably at an amount of 0.9 to 3.6 wt%, in particular at an amount of 1 .0 to 3.5 wt%, particularly at an amount of 1 .0 to 3.4 wt%, advantageously at an amount of 1 .0 to 3.3 wt%, more advantageously at an amount of 1 .0 to 3.2 wt%, even more advantageously at an amount of 1 .0 to 3.1 wt%, in particular at an amount of 1 .0 to 3.0 wt%, more particular at an amount of 1 .0 to 2.9 wt%, preferably at an amount of 1 .0 to 2.8 wt%, more preferably at an amount of 1 .0 to 2.7 wt%, advantageously at an amount of 1 .0 to 2.6 wt%, even more preferably at an amount of 1 .0 to 2.5 wt%, for example 1 .1 wt%, 1 .2 wt%, 1 .3 wt%, 1 .4 wt%, 1 .5 wt%, 1 .6 wt%, 1 .7 wt%, 1 .8 wt%, 1 .9 wt%, 2.0 wt%, 2.1 wt%, 2.2 wt%, 2.3 wt%, 2.4 wt%.

[0064] More particularly, the at least stabilizer of the milk of lime of the present invention is chosen in the group comprising carbohydrate, polyalcohol, carbohydrate-acid, polyalcohol-acid, small molecule organic di-acid, small molecule organic poly-acid, and their mixture, more preferably said at least stabilizer is chosen in the group comprising xylitol, sodium gluconate or gluconic acid, a mixture of sugar comprising at least glucose and fructose, and their mixture.

[0065] Other embodiments of the milk of lime according to the present invention are mentioned in the appended claims.

[0066] The present invention also concerns a process for manufacturing a milk of lime comprising the step of : milling of lime particles, in suspension in an aqueous phase, said lime particles having an initial particle size distribution with a characteristic diameter d?8 lower than or equal to 200 pm, preferably lower than or equal to 150 pm, more preferably lower than or equal to 100 pm, as measured by laser diffraction (with a Beckman-Coulter LSI 3 320 equipment using methanol as carrier solvent and ultrasound sonication pretreatment 4min at 100W) to obtain a particle size distribution with a characteristic diameter dso comprised between 1 .0 and 3.5 pm and d?8 lower than or equal to 15 pm, adding, in said aqueous phase, a first dose of at least a polymer dispersant at an amount of 0.1 to 2.0 wt% of active polymer dispersant based on weight of the solid content of fine lime particles, adding, in said aqueous phase, at least a stabilizer at an amount of 0.5 to 4.0 wt% of active stabilizer based on weight of the solid content of fine lime particles, collecting a milk of lime having an amount of solid content of fine lime particles higher or equal to 30 wt% and lower or equal to 70 wt% based on weight of the milk of lime and a particle size distribution with a characteristic diameter dso comprised between 1 .0 and 3.5 m and d?8 lower than or equal to 15 m, and a viscosity above 2000 cP at 1 s-1shear rate and a viscosity lower than 200 cP at 100 S’1shear rate measured with a Anton Paar MCR102 Rheometer using cone & plate geometry at room temperature of ca. 20°C.

[0067] In a preferred embodiment, the step of adding said first dose of at least a polymer dispersant in said aqueous phase and / or said step of adding said at least a stabilizer in said aqueous phase of said process for manufacturing a milk of lime according to the present invention, is before said step of milling said lime particles.

[0068] Preferably, the step of adding said first dose of at least a polymer dispersant in said aqueous phase and / or said step of adding said at least a stabilizer in said aqueous phase of said process for manufacturing a milk of lime according to the present invention, is after said step of milling said lime particles.

[0069] In a preferred embodiment of the process for manufacturing a milk of lime according to the present invention, the first dose of at least a polymer dispersant in said aqueous phase is added before and / or after and / or simultaneously and / or in sequence to said addition of said at least a stabilizer.

[0070] In another preferred embodiment of the process for manufacturing a milk of lime according to the present invention, the lime particles are dry hydrated lime and / or wet slaked quicklime.

[0071] Even more preferably, the step of adding said first dose of at least a polymer dispersant in said aqueous phase and said step of adding said at least a stabilizer in said aqueous phase of said process for manufacturing a milk of lime according to the present invention, are before said step of milling said lime particles, preferably said addition of at least a stabilizer is realized before and / or after and / or simultaneously and / or in sequence to said addition of said at least a polymer dispersant.

[0072] In another embodiment, the step of adding said first dose of at least a polymer dispersant in said aqueous phase and said step of adding said at least a stabilizer in said aqueous phase of said process for manufacturing a milk of lime according to the present invention, are after said step of milling said lime particles, preferably said addition of at least a stabilizer is realized before and / or after and / or simultaneously and / or in sequence to said addition of said at least a polymer dispersant.

[0073] In another preferred embodiment of the process for manufacturing a milk of lime according to the present invention, the step of adding said at least a stabilizer in said aqueous phase is before said step of milling said lime particles, and said step of adding said first dose of at least a polymer dispersant in said aqueous phase is after said step of milling said lime particles.

[0074] In a preferred embodiment of the process for manufacturing a milk of lime according to the present invention, the step of adding said first dose of at least a polymer dispersant in said aqueous phase is before said step of milling said lime particles, and said step of adding said at least a stabilizer in said aqueous phase is after said step of milling said lime particles.

[0075] Preferably the process for manufacturing a milk of lime according to the present invention, comprises an additional step of concentration of said formed milk of lime before said step of collection, preferably by filtration, high pressure filtration, centrifugation, forced and / or accelerated settling.

[0076] More preferably the process for manufacturing a milk of lime according to the present invention, comprises an additional step of dispersion, in said formed milk of lime, a second dose of at least a polymer dispersant at an amount of 0.1 to 1 .0 wt% of active polymer dispersant based on weight of a solid content of fine lime particles, preferably with a combination with mechanical agitation.

[0077] Other embodiments of the process for manufacturing a milk of lime according to the present invention are mentioned in the appended claims.

[0078] The present invention further concerns an utilization of the milk of lime according to the invention or said milk of lime manufactured by the process according to the invention, for the treatment of water, sludge, neutralization of acid waste, pH adjustment in chemical and nonferrous metal industries, paper and PCC industries, depolluting acid flue gases, or in the building and agriculture sectors. Other embodiments of the utilization of the milk of lime according to the present invention are mentioned in the appended claims.

[0079] Other characteristics and advantages of the present invention will be derived from the non-limitative following description, and by making reference to the examples.

[0080] Examples. -

[0081] The particle size distribution in the following examples and comparative examples were measured with a Beckman-Coulter LSI 3320 equipment using methanol as carrier solvent and ultrasound sonication pretreatment 4min at 100W.

[0082] Measurement of viscosity over a range of shear rates (i.e. from 1 s-1 to 100 s-1 ) are done with an Anton Paar MCR102 Rheometer using cone & plate geometry or cup & cylinder geometry or cup & vane geometry.

[0083] Measurement of viscosity at 100 rpm are done using a Brookfield DV-3 Rheometer with spindle 63, if viscosity is > 300 cP, or with spindle 62, if viscosity is < 300 cP.

[0084] According to the present invention, measuring the height (& thus volume for a bottle with constant diameter) of clear supernatant on a 1 dm3bottle of ca. 18cm liquid height. It is found that, this surprisingly corresponds reasonably well to the level of clear supernatant on a I m3IBC of ca. 1 m3liquid height.

[0085] Example 1. - Preparation of a milk of lime having a particle size distribution with a characteristic diameter d25 of 1 .41 m, dso of 2.5 m and d?8 of 1 1 .7 pm, a viscosity of above 2000 cP at 1 s-1shear rate, 500 cP at 5 s-1shear rate and a viscosity of 35 cP at 100 S’1shear rate.

[0086] A milk of lime containing 45.5 wt% of dry solid content of fine lime particles based on weight of the milk of lime,

[0087] 0.1 wt% of ViscoCrete® 3027 from Sika® (active polycarboxylate polyether comb copolymer as active dispersant) relative to said total dry solid content of said milk of lime,

[0088] 0.7 wt% of EPB 1442049 dispersant from Chryso (active polycarboxylate polyether comb copolymer as active polymer dispersant) relative to said total dry solid content of said milk of lime, 1.0 wt% of active stabilizer (Xylitol) relative to said total dry solid content of said milk of lime, with a particle size distribution with a characteristic diameter d25 of 1 .41 pm, dso of 2.5 pm and d?8 of 1 1 .7 pm, is prepared.

[0089] 5.5 metric tons of potable water are added to a 20 m3container with 2 agitators with 800 mm impellers, each driven by a 4 kW motor and operated a rotation speed of 60 rpm. 40 kg of dry xylitol and 12 kg of ViscoCrete® 3027 dispersant supplied by Sika® are added to the water & dispersed during 10 min of agitation. Then 4.5 metric tons of dry hydrate with a specific surface area of 7.5m2 / g as measured according to the BET method are added and dispersed during 15 min under agitation.

[0090] The obtained suspension has a viscosity of 140 mPa.s as measured with a Brookfield DV-3 Rheometer and Dso of 5.9 pm and a D?8 of 87.5 pm. Its solid content was found to be 45.5 wt% by weight loss measurement by IR thermobalance.

[0091] It is then milled with a Bachofen KD190 industrial rotary bead mill using 1 .2-1 .4 mm zircon oxide beads with a filling level of ca. 60 % of the free volume of the mill chamber and operating at maximum rotor speed for the mill (= speed controller at 100%) at a throughput of 1.6 m3 / h. At the mill exit, the suspension was found to have a viscosity of 444 mPa.s. After the mill, 0.7wt% of EPB1442049 dispersant of Chryso per wt dry hydrate were added by a dosing pump into the product transfer line before a static mixer. This yielded a viscosity of ca. 120 mPa.s on the final milk of lime with a d25 of 1 .41 pm, dso of 2.5 pm and a d?8 of 1 1 .7 pm.

[0092] Results over 28 days are given in Figure 1.

[0093] We observe a drop in viscosity over the 1stday of storage to a viscosity of 25 to 40cP. Despite this very low viscosity, this suspension showed low settling. Stored in an IBC for 3 months, we observe 180mm of clear supernatant over a height of 1 m3(= 18 vol% height) thus < 20 cm and < 20 vol% height clear supernatant. It was observed that even after 3 months, the suspension flowed readily & with low viscosity from the bottom valve.

[0094] A sample was taken from the bottom valve after 3 months, adjusted to 45 wt% by water addition & its viscosity as well as the storage & loss moduli measured over a range of shear rates from 1 to 100 sec-1 with an Anton-Paar MCR102 Rheometer with a cone & plate geometry. While it shows pseudoplastic (shear thinning) behavior, the decrease of viscosity with increasing shear rate is stronger than for typical lime slurries with an exponent (n-1 ) for a power law fit of ca. -0.85.

[0095] The viscosity observed here is ca. 500 mPa.s for a shear rate of 5 sec-1 and ca. 35 mPa.s for a shear rate of 100 sec-1 .

[0096] Storage modulus G' and loss modulus G" vs Deformation (%) for Example 1 according to the invention is shown in Figure 2.

[0097] Storage modulus G' and loss modulus G" vs Shear stress (Pa) for Example 1 according to the invention is shown in Figure 3.

[0098] The results on the storage modulus G' and loss modulus G" explain the comparatively low settling but high flowability even under extended storage. At their transition point the deformation is slightly greater 0.1 % and the (critical) shear stress is greater than 1 Pa, while G' is greater than 2x G" before the transition point & G" becoming greater than 2x G' after it. This is providing resistance to settling at rest as well as high fluidity under flow to this formulation - even after 3 months of storage.

[0099] Example 2. - Preparation of a milk of lime having a particle size distribution with a characteristic diameter d25 of 1 .33 m, dso of 2.2 pm and d?8 of 9.1 pm, a viscosity of 8000 cP at 1 S’1, 2000 cP at 5 S’1shear rate and a viscosity of 160 cP at 100 S’1shear rate.

[0100] A milk of lime containing 45.4 wt% of dry solid content of fine lime particles based on weight of the milk of lime,

[0101] 0.23 wt% of NeomereOTech 646 from Chryso (active polycarboxylate polyether comb copolymer as active polymer dispersant) relative to said total dry solid content of said milk of lime,

[0102] 0.99 wt% of active stabilizer (Xylitol) relative to said total dry solid content of said milk of lime, with a particle size distribution with a characteristic diameter d25 of 1 .33 pm, dso of 2.2 pm and d?8 of 9.1 pm, is prepared.

[0103] 40,9 g of dry xylitol (stabilizer) and 7.07 g of NeomereOTech 646 dispersant (dispersant by Chryso SAS with ca. 20 wt% active content) are added to 5000 g of tap water and dissolved by mixing with an anchor type stirrer at 200 rpm. Then 4090 g of a dry hydrate powder with a Dso of 9.4 m and a D?8 of 88.4 pm and a specific surface area of 1 1 .5 m2 / g (as measured by a Micromeritics Tristar equipment using the BET nitrogen adsorption-desorption method) is added & dispersed by agitation with the same stirrer at 300 rpm during 30 min. The obtained suspension has a viscosity of 525 mPa.s as measured with a Brookfield DV-3 Rheometer at a rotation speed of 100 rpm using the suitable spindle (spindle 63). A solid content of 45.4 wt% is measured on a Sartorius Infrared Thermobalance after drying at 1 10°C.

[0104] The obtained suspension is then milled with a Dynomill 1.4 dm3laboratory rotary bead mill at a rotor speed of 1500 rpm using 0.8 mm avg diameter zircon oxide beads at a ca. 75 %vol filling level (relative to mill chamber free volume) at a throughput of 24 dm3 / h, to obtain a fineness of Dso of 2.2 pm and a D?8 of 9.1 pm - measured using the same equipment & procedure as described above.

[0105] 41 .0 g of NeomereOTech 646 dispersant (dispersant by Chryso SAS with ca. 20 wt% active content) are added under agitation with the anchor stirrer as described. The formulation at this stage has a viscosity of 456 mPa.s as measured with the abovementioned Brookfield @100rpm.

[0106] Viscosity and decantation are monitored weekly on samples stored at rest for 28 days. For the viscosity measurement, the sample is shaken by hand before measurement.

[0107] The viscosity as well as the storage & loss moduli of the fresh formulation are measured over a range of shear rates from 1 to 100 sec-1 with an Anton-Paar MORI 02 Rheometer with a cone & plate geometry.

[0108] As can be observed in the Figure 4, the exponent (n-1 ) of a power law fit is -0.86, allowing for a faster than typical transition from a stiff resting state to a fluid state under flow or agitation.

[0109] The viscosity observed here is ca. around 8000 cP / mPa.s at 1 sec-1 shear rate, 2000 mPa.s for a shear rate of 5 sec-1 and ca. 160 mPa.s for a shear rate of 100 sec-1. This milk of lime proves readily flowable and readily pumpable. Sedimentation is low with 6 vol% clear supernatant after 28 days of storage.

[0110] Storage modulus G' and loss modulus G" vs Deformation (%) for Example 2 according to the invention is shown in Figure 5.

[0111] Storage modulus G' and loss modulus G" vs Shear stress (Pa) for Example 2 according to the invention is shown in Figure 6. The results on the storage modulus G' and loss modulus G" explain the comparatively low settling but high flowability for this slightly more viscous product. At their transition point the deformation is notably greater 0.1% and the (critical) shear stress is ca. 8 Pa, while G' is greater than 2x G" before the transition point & G" becoming greater than 2x G' after it. This is providing resistance to settling at rest as well as high fluidity under flow to this milk of lime according to the invention.

[0112] Example Comparative 1. - Preparation of a milk of lime having a particle size distribution with a characteristic diameter dso of 3.5 m and d?8 of 19.3 pm.

[0113] A milk of lime containing 45.4 wt% of dry solid content of fine lime particles based on weight of the milk of lime,

[0114] 0.08 wt% of NeomereOTech 646 from Chryso (active polycarboxylate polyether comb copolymer as active dispersant) relative to said total dry solid content of said milk of lime,

[0115] 0.75 wt% of active stabilizer (Sucrose) relative to said total dry solid content of said milk of lime, with a particle size distribution with a characteristic diameter dso of 3.5 pm and d?8 of 1 .3 pm, is prepared.

[0116] 30.7 g sucrose (crystalline table sugar) is added to 5000 g of water and dissolved by mixing with an anchor type stirrer at 200 rpm. Then 4090 g of the same dry hydrate powder as in the previous with a Dso of 6.1 pm and a D98 of 77.6 pm is added & dispersed by agitation w the same stirrer at 300 rpm during 30 min. A solid content of 45.6 wt% is measured on a Sartorius Infrared Thermobalance after drying at 1 10 °C.

[0117] The obtained suspension is then milled with a Dynomill 1.4 dm3laboratory rotary bead mill at a rotor speed of 1200 rpm using 1 .25 mm avg diameter zircon oxide beads at a ca. 60 %vol filling level (relative to mill chamber free volume), to obtain a fineness of Dso of 3.5 pm and a D98 of 19.3 pm - using the same equipment & procedure as described above. The obtained suspension has a viscosity of ca. 1000 mPa.s as measured with a Brookfield DV-3 Rheometer at a rotation speed of 100 rpm using the suitable spindle (spindle 63) . 16.4g of NeomereOtech 646 dispersant (dispersant by Chryso SAS with ca. 20 wt% active content) is added to the suspension under agitation with the said anchor stirrer at 300 rpm for 10 minutes. The obtained viscosity is 82 mPa.s - same equipment & procedure as above.

[0118] Viscosity and decantation are monitored weekly on samples stored at rest for 28 days. For the viscosity measurement, the sample is shaken by hand before measurement. It is observed that the viscosity increases on the first day to 522 mPa.s and stabilizes at ca. 700 mPa.s after ca. 1 week. The sample for the decantation test is not moved at all & after 28 days 12 vol% in height in clear supernatant over a sample height of ca. 16 cm is noted.

[0119] Results over 28 days are given in Figure 7.

[0120] This comparative milk-of-lime out of the present invention is far less stable over time in viscosity than the formulations of Example 1 & Example 2 (milks of lime according to the present invention) and as a result far less easily flowable. And still despite of its high viscosity of ca. 700 mPa.s measured with the abovementioned Brookfield, it shows 10% of clear supernatant after just 1 week. More critically, upon gently emptying the sample bottle after 1 month of storage, more than 40% by weight of the product remained as bottom residue in the bottle.

[0121] The viscosity as well as the loss & storage moduli of this suspension are measured over a range of shear rates from 1 to 100 sec-1 with an Anton-Paar MORI 02 Rheometer with a cup & cylinder geometry.

[0122] It is found to decrease with increasing shear rate and shear stress as is typical for shear-thinning / pseudoplastic suspensions like typical lime hydrate suspensions. While at very high shear rates like 60 to 100 sec-1 , it displays a similar low viscosity level (ca. 90 mPa.s at 100 sec-1 ) as the suspensions in Examples 1 & 2, at low shear rate of 5 sec-1 , we observe viscosities of ca. 720 mPa.s, which is too low to prevent the formation of a bottom residue.

[0123] The exponent (n-1 ) for the power law fit of viscosity vs shear rate is -0.73 (see graphic above) - which is a typical value for unformulated as well as typical formulated lime hydrate suspension.

[0124] The results on the storage modulus G' and loss modulus G" explain the high bottom residue formation due to settling for this notably more viscous product. At their transition point the deformation is notably lower than 0.1 % and the (critical) shear stress is spread over a range of ca. 0.4 to 0.8 Pa, thus notably less than 1 Pa, while G' is greater than 2x G" before the transition point & G" becoming greater than 2x G' after it. This provides reduced resistance to settling at rest. Combined with the lower shear thinning effect, resulting in practice in a product more viscous at common, moderate flow rates (see above: 2500 cP / mPa.s at 1 sec-1 shear rate, 720 mPa.s at 5 sec-1 shear rate), this makes this formulation less easy to handle (i.e. store, homogenize by agitation, pump & dose) than those of example 1 & 2.

[0125] Storage modulus G' and loss modulus G" vs Shear force (Pa) for Example Comparative 1 out of the invention is shown in Figure 8.

[0126] Storage modulus G' and loss modulus G" vs Deformation (%) for Example Comparative 1 out of the invention is shown in Figure 9. It should be understood that the present invention is not limited to the described embodiments and that variations can be applied without going outside of the scope of the claims.

Claims

CLAIMS1 . Milk of lime comprising on amount of dry solid content of fine lime particles higher or equal to 30 wt% and lower or equal to 70 wt% based on weight of the milk of lime, in aqueous phase, said milk of lime comprising at least a polymer dispersant at an amount of 0.1 to 2.0 wt% of active polymer dispersant relative to said total dry solid content of said milk of lime, and at least a stabilizer at an amount of 0.5 to 4.0 wt% of active stabilizer relative to said total dry solid content of said milk of lime, wherein said fine lime particles of said milk of lime having a particle size distribution with a characteristic diameter dso comprised between 1.0 and 3.5 m and d?8 lower than or equal to 15 pm as measured by laser diffraction (with a Beckman-Coulter LSI 3 320 equipment using methanol as carrier solvent and ultrasound sonication pretreatment 4min at 100W), and wherein said milk of lime having a viscosity above 2000 cP at 1 s-1shear rate and a viscosity lower than 200 cP at 100 S’1shear rate measured with a Anton Paar MCR102 Rheometer using cone & plate geometry at room temperature of ca. 20°C.

2. Milk of lime according to claim 1 , wherein said lime particles present a specific surface area < 12 m2 / g, preferably < 10 m2 / g, more preferably < 9 m2 / g, ideally < 8 m2 / g (as measured by a Micromeritics Tristar equipment using the BET nitrogen adsorption-desorption method as described in standard DIN 66134).

3. Milk of lime according to claim 1 or claim 2, producing a decantation of less than 5 wt% bottom solid residues measured during 28 days, more preferably measured during 42 days, even more preferably measured during 56 days.

4. Milk of lime according to any one of claims 1 to 3, producing a decantation of less than 20 vol% supernatant measured during 28 days, more preferably measured during 42 days, even more preferably measured during 56 days.

5. Milk of lime according to any one of claims 1 to 4, wherein said fine lime particles of said milk of lime having a particle size distribution with a characteristic diameter d25 higher than or equal to 0.4 pm when said characteristic diameter dso of said fine lime particles of said milk of lime is higher than or equal to 1 .0 pm.

6. Milk of lime according to any one of claims 1 to 5, wherein said fine lime particles of said milk of lime having a particle size distribution with a characteristic diameter dso comprised between 1 .0 and 3.4 pm, preferably between 1.0 and 3.3 pm, more preferably between 1.0 and 3.2 pm, even more preferably between 1 .0 and 3.1 pm, in particular between 1 .1 and 3.0 pm, preferably between 1.2 and 3.0 pm, more preferably between 1.3 and 3.0 pm, even more preferably between 1.4 and 3.0 pm, advantageously between 1.5 and 3.0 pm, more advantageously between 1 .6 and 3.0 pm, even more advantageously between 1 .7 and 3.0 pm, in particular between 1 .8 and 3.0 pm, more particularly between 1 .9 and 3.0 pm, preferably between 2.0 and 3.0 pm, more preferably between 2.1 and 3.0 pm, even more preferably between 2.1 and 2.9 pm, in particular between 2.2 and 2.9 pm, advantageously between 2.2 and 2.8 pm, for example 2.3 pm, 2.4 pm, 2.5 pm, 2.6 pm, 2.7 pm.

7. Milk of lime according to any one of claims 1 to 6, wherein said fine lime particles of said milk of lime having a particle size distribution with a characteristic diameter d?8 lower than or equal to 14 pm, advantageously lower than or equal to 13 pm, preferably lower than or equal to 12 pm, more preferably lower than or equal 1 1 pm, even more preferably lower than or equal 10 pm.

8. Milk of lime according to any one of preceding claims, wherein said amount of solid content of fine lime particles is higher or equal to 35 wt% and lower or equal to 65 wt%, preferably higher or equal to 40 wt% and lower or equal to 60 wt%, even more preferably higher or equal to 40 wt% and lower or equal to 55 wt%, advantageously higher or equal to 40 wt% and lower or equal to 50 wt%.

9. Milk of lime according to any one of preceding claims, wherein said at least polymer dispersant is a polycarboxylate polyether comb copolymer, preferably the polycarboxylate polyether comb copolymer presents a main chain containing (meth)acrylate units and lateral chains comprising oxyethylene or oxypropylene groups.

10. Milk of lime according to any one of preceding claims, wherein said at least stabilizer is present at an amount of 0.6 to 3.9 wt%, preferably at an amount of 0.7 to 3.8 wt%, more preferably at an amount of 0.8 to 3.7 wt%, even more preferably at an amount of 0.9 to 3.6 wt%, in particular at an amount of 1 .0 to 3.5 wt%, particularly at an amount of 1 .0 to 3.4 wt%, advantageously at an amount of 1.0 to 3.3 wt%, more advantageously at an amount of 1.0 to 3.2 wt%, even more advantageously at an amount of 1 .0 to 3.1 wt%, in particular at an amount of 1 .0 to3.0 wt%, more particular at an amount of 1 .0 to 2.9 wt%, preferably at an amount of 1 .0 to 2.8 wt%, more preferably at an amount of 1 .0 to 2.7 wt%, advantageously at an amount of 1 .0 to 2.6 wt%, even more preferably at an amount of 1 .0 to 2.5 wt%.1 1 . Milk of lime according to any one of preceding claims, wherein said at least stabilizer is chosen in the group comprising carbohydrate, polyalcohol, carbohydrate-acid, polyalcohol-acid, small molecule organic di-acid, small molecule organic poly-acid, and their mixture, more preferably said at least stabilizer is chosen in the group comprising xylitol, sodium gluconate or gluconic acid, a mixture of sugar comprising at least glucose and fructose, and their mixture.

12. Process for manufacturing a milk of lime comprising the step of: Milling of lime particles, in suspension in an aqueous phase, said lime particles having an initial particle size distribution with a characteristic diameter d?8 lower than or equal to 200 pm, preferably lower than or equal to 150 pm, more preferably lower than or equal to 100 pm, as measured by laser diffraction (with a Beckman-Coulter LSI 3 320 equipment using methanol as carrier solvent and ultrasound sonication pretreatment 4min at 100W) to obtain a particle size distribution with a characteristic diameter dso comprised between 1 .0 and 3.5 pm and d?8 lower than or equal to 15 pm, adding, in said aqueous phase, a first dose of at least a polymer dispersant at an amount of 0.1 to 2.0 wt% of active polymer dispersant based on weight of the solid content of fine lime particles, adding, in said aqueous phase, at least a stabilizer at an amount of 0.5 to 4.0 wt% of active stabilizer based on weight of the solid content of fine lime particles, collecting a milk of lime having an amount of solid content of fine lime particles higher or equal to 30 wt% and lower or equal to 70 wt% based on weight of the milk of lime and a particle size distribution with a characteristic diameter dso comprised between 1 .0 and 3.5 pm and d?8 lower than or equal to 15 m, and a viscosity above 2000 cP at 1 s-1shear rate and a viscosity lower than 200 cP at 100 S’1shear rate measured with a Anton Paar MCR102Rheometer using cone & plate geometry at room temperature of ca. 20°C.

13. Process for manufacturing a milk of lime according to claim 12, wherein said step of adding said first dose of at least a polymer dispersant in said aqueous phase and / or said step of adding said at least a stabilizer in said aqueous phase, is before said step of milling said lime particles.

14. Process for manufacturing a milk of lime according to claim 12, wherein said step of adding said first dose of at least a polymer dispersant in said aqueous phase and / or said step of adding said at least a stabilizer in said aqueous phase, is after said step of milling said lime particles.

15. Process for manufacturing a milk of lime according to any one of claims 12 to 14, wherein said first dose of at least a polymer dispersant in said aqueous phase is added before and / or after and / or simultaneously and / or in sequence to said addition of said at least a stabilizer.

16. Process for manufacturing a milk of lime according to any one of claims 12 to 15, wherein said lime particles are dry hydrated lime and / or wet slaked quicklime.

17. Process for manufacturing a milk of lime according to any one of claims 12 to 16, wherein said step of adding said first dose of at least a polymer dispersant in said aqueous phase and said step of adding said at least a stabilizer in said aqueous phase, are before said step of milling said lime particles, preferably said addition of at least a stabilizer is realized before and / or after and / or simultaneously and / or in sequence to said addition of said at least a polymer dispersant.

18. Process for manufacturing a milk of lime according to any one of claims 12 to 16, wherein said step of adding said first dose of at least a polymer dispersant in said aqueous phase and said step of adding said at least a stabilizer in said aqueous phase, are after said step of milling said lime particles, preferably said addition of at least a stabilizer is realized before and / or after and / or simultaneously and / or in sequence to said addition of said at least a polymer dispersant.

19. Process for manufacturing a milk of lime according to any one of claims 12 to 16, wherein said step of adding said at least a stabilizer in said aqueous phase is before said step of milling said lime particles, and said step of adding said first dose of at least a polymer dispersant in said aqueous phase is after said step of milling said lime particles.

20. Process for manufacturing a milk of lime according to any one of claims 12 to 16, wherein said step of adding said first dose of at least a polymer dispersant in said aqueous phase is before said step of milling said lime particles, and said step of adding said at least a stabilizer in said aqueous phase is after said step of milling said lime particles.21 . Process for manufacturing a milk of lime according to any one of claims 12 to 20, comprising an additional step of concentration of said formed milk of lime before said step of collection, preferably by filtration, high pressure filtration, centrifugation, forced and / or accelerated settling.

22. Process for manufacturing a milk of lime according to any one of claims 12 to 21 , comprising an additional step of dispersion, in said formed milk of lime, a second dose of at least a polymer dispersant at an amount of 0.1 to 1 .0 wt% of active polymer dispersant based on weight of a solid content of fine lime particles, preferably with a combination with mechanical agitation.

23. Process for manufacturing a milk of lime according to any one of the claims 12 to 22, wherein said lime particles present a specific surface area < 12 m2 / g, preferably < 10 m2 / g, more preferably < 9 m2 / g, ideally < 8 m2 / g (as measured by a Micromeritics Tristar equipment using the BET nitrogen adsorptiondesorption method as described in standard DIN 66134).

24. Utilization of said milk of lime according to claims 1 to 1 1 or said milk of lime manufactured by the process according to claims 12 to 23, for the treatment of water, sludge, neutralization of acid waste, pH adjustment in chemical and nonferrous metal industries, paper and PCC industries, depolluting acid flue gases, or in the building and agriculture sectors.

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