Device and method for preparing cooling water on demand

Abstract

The invention relates to a preparation method for preparing cooling water which aims to reproduce a target cooling water by using at least two aqueous solutions selected from an industrial water solution, a cationic ion exchanger-treated water solution, a demineralised water solution and an aqueous solution containing Mg2+ and Ca2+ ions. The invention also relates to a casting method using the cooling water obtained according to the preparation method and to a casting device (100) comprising the preparation device.

Description

[0001] DESCRIPTION

[0002] Title of the invention: Device and method for preparing cooling water on demand

[0003] Technical field of the invention

[0004] The present invention relates to a method for preparing cooling water intended to cool a product during a metallurgical transformation operation and in particular for casting applications of foundry parts, for example in a process for casting a product, preferably made of aluminum alloy. The invention also relates to a casting device comprising a device for preparing cooling water.

[0005] State of the art

[0006] It is known from the state of the art (Gildemeister D., Light Metals 2014, pp885-891), that the composition of cooling water intended for a metallurgical transformation process can have an effect on the cooling process. In particular, when forming a plate in semi-continuous casting, the use of cooling water with an uncontrolled and / or unsuitable composition can generate negative effects on the formation of the plate such as: cracks, splits, excessive curvatures of the plate foot, swellings that can block the casting process, or cause breakthroughs of liquid metal, etc.Although the influence of each parameter constituting the cooling water is not yet fully known, it has already been demonstrated that alkalinity (characterized by the alkalimetric titer (TA) and the total alkalimetric titer (TAC)), hardness (characterized for example by the hydrotimetric titer (TH)), pH, conductivity, or turbidity, have an impact on heat transfer.

[0007] Thus, there is a need to be able to vary the cooling water parameters in order to study their effect and, if necessary, to be able to use optimized water. Indeed, there is a need to be able to control the quality of the water at the start of the semi-continuous casting and to be able to use cooling water different from the water available on the industrial site.

[0008] Furthermore, before implementing a metallurgical transformation process on an industrial scale, it is common to carry out cooling tests by simulation or real tests, to determine the cooling conditions adapted to a given industrial water. However, once these cooling conditions have been determined, they cannot generally be transposed to all industrial waters, which makes it difficult to transfer a metallurgical transformation process from one industrial site to another industrial site. Furthermore, given that the testing means for determining cooling conditions are not systematically present on the production site, one solution could be to carry out these tests on a site other than the production site and distant from it. However, this solution requires, on this other site, having a sufficient quantity of water from the production site available.The main problem with such a cooling water supply is that a large volume is required, which involves obvious logistical and cost problems. In addition, changes in the composition of the cooling water can occur during transport.

[0009] Thus, there is a need to be able to have cooling water on demand, for the tests carried out during the determination of the cooling conditions, which is a faithful reproduction of the cooling water which will then be used on the production site. Alternatively, there is also a need to be able to have casting cooling water with a particular composition allowing to have a constant thermal efficiency over time, in particular during the transient phase of start-up. However, this problem is difficult to solve because the control and modification of the composition of a water is not easy, in particular when it concerns the concentration of dissolved CaSO4 and MgSO4 salts.

[0010] Statement of the invention

[0011] The present invention aims to propose a solution which responds to all or part of the aforementioned problems.

[0012] This aim can be achieved by implementing a method for preparing cooling water to cool a product during a metallurgical transformation operation and in particular for semi-continuous casting applications of foundry products, the preparation method comprising the following steps:

[0013] - a step of analyzing the composition of a target cooling water so as to determine a target final composition (cfc). The analysis result is substantially identical to the target final composition (cfc). According to the invention, the term substantially must be understood as being able to give rise to a rounding of at least one useful parameter. Indeed, the analysis step makes it possible to determine at least one useful parameter chosen from the group comprising a calcium concentration (THCa), a magnesium concentration (THMg), a complete alkalimetric titer (TAC), an alkalimetric titer (TA), a hydrotimetric titer (TH), a concentration of chloride ions (CCI), sulfates (CS), bromides (CBr), sodium (CNa) and a pH. The target composition (cfc) can therefore be identical to the analysis result or equal to + / - 10%, preferably + / - 5% of the analysis result.- a step of providing at least one first aqueous solution characterized by a first composition and at least one second aqueous solution distinct from the first aqueous solution and characterized by a second composition, said first aqueous solution and said second aqueous solution being chosen from the group consisting of:.

[0014] . of an industrial water solution,

[0015] . of a water solution treated on a cationic ion exchanger,

[0016] . of a solution of demineralized water,

[0017] . of an aqueous solution containing Mg ions 2+ and that 2+ ,

[0018] - a mixing phase comprising a first mixing step in which a first volume of the first aqueous solution and a second volume of the second aqueous solution are mixed, so as to produce a mixing volume of a mixing solution characterized by a mixing composition, and constituting all or part of the cooling water, said first volume of the first aqueous solution and second volume of the second aqueous solution being determined by a calculation step (E7) as a function of said first composition and said second composition, each of the first composition (cl), the second composition (c2), the mixing composition (cml), and the target final composition (cfc), is defined by at least one useful parameter chosen from the group comprising a calcium concentration (THCa), a magnesium concentration (THMg), a total alkalimetric titer (TAC), an alkalimetric titer (TA),a hydrotimetric titer (TH), a concentration of chloride ions (CCI), sulfates (CS), bromides (CBr), sodium (CNa) and a pH,

[0019] - said calculation step (E7) in which the first volume (VI) of the first aqueous solution and the second volume (V2) of the second aqueous solution are determined as a function of said at least one useful parameter defining the first composition (cl), of said at least one useful parameter defining the second composition (c2), and so that said at least one useful parameter defining the mixture composition (cml) tends towards said at least one useful parameter defining the target final composition (cfc)

[0020] Industrial water solution means industrial water having a conductivity of less than or equal to 2000 pS / cm, preferably between 100 pS / cm and 2000 pS / cm. Preferably, the hydrotimetric strength of the industrial water is less than or equal to 80°f, preferably less than or equal to 50°f. Industrial water means water used for industrial purposes, as opposed to domestic water and agricultural water.

[0021] By cationic ion exchanger treated water solution is meant a solution with a conductivity greater than or equal to 100 pS / cm, which is either decarbonated water such as TH <TAC + 3°f, soit une eau permutée telle TH < 3°f, où TH et TAC sont respectivement le titre hydrotimétrique et le titre alcalimétrique de la solution d'eau traitée sur échangeur d'ions cationiques considérée exprimés en degré français.

[0022] A demineralized water solution is a solution with a conductivity of less than or equal to 100 pS / cm. Demineralized water is water that no longer contains any dissolved ions (such as Ca2+ or HCO3-...), nor any dissolved neutral mineral substances (aluminum hydroxides (AI(OH)3) or iron(III) hydroxides (Fe(OH)3), dissolved silica (Si(OH)4)...). The hydrotimetric strength of demineralized water is less than or equal to 1°f.

[0023] By "aqueous solution containing Mg ions 2+ and that 2+ ", means a solution whose conductivity is greater than or equal to 20 pS / cm, and such that its hydrometric titer TH is greater than 50 °f. Preferably, the hydrometric titer TH of the aqueous solution containing Mg ions 2+ and that 2+ is at least five (5) times greater than the hydrometric titer of the industrial water solution. By "aqueous solution containing Mg ions 2+ and that 2+", we mean a solution whose concentration of Mg ions 2+ and that 2+ is greater than the concentration of Mg ions 2+ and that 2+ industrial water solution, cationic ion exchange treated water solution, demineralized water solution. Furthermore, and advantageously, the use of the aqueous solution containing Mg ions 2+ and that 2+ makes it easier to produce, on demand, cooling water with a composition close to the target final composition. Indeed, the use of the aqueous solution containing Mg ions 2+ and that 2+ is particularly advantageous when water is needed that is harder than the industrial water available, or to stabilize a water composition in relation to seasonal variations.

[0024] The provisions described above make it possible to propose a method for preparing cooling water having a composition close to a target final composition.

[0025] The preparation process may further have one or more of the following characteristics, taken alone or in combination.

[0026] According to one embodiment, the providing step comprises providing a third or fourth aqueous solution chosen distinct from each other and distinct from the first aqueous solution and the second aqueous solution, said third or fourth aqueous solution being chosen from the group consisting of:

[0027] - the industrial water solution,

[0028] - the water solution treated on a cationic ion exchanger,

[0029] - demineralized water solution,

[0030] - the aqueous solution containing Mg ions 2+ and that 2+, In this case, the first mixing step comprises mixing the third and / or fourth aqueous solution with the first and second aqueous solutions. It is therefore understood that the phase of mixing the first volume of the first aqueous solution and the second volume of the second aqueous solution is not limiting and that it may also comprise mixing a number of volumes of distinct aqueous solutions greater than two.

[0031] According to one embodiment, the cooling water is obtained by a mixture of four volumes of aqueous solutions, each volume of aqueous solution coming respectively from the industrial water solution, the water solution treated on a cationic ion exchanger, the demineralized water solution, and the aqueous solution containing Mg ions. 2+ and that 2+ .

[0032] According to one embodiment, the target final composition corresponds to the composition of cooling water available on an industrial production site, for example a foundry parts production site.

[0033] According to one embodiment, the calculation step is implemented by a calculation unit configured to calculate the first volume of the first aqueous solution and the second volume of the second aqueous solution so as to minimize a difference between said at least one useful parameter defining the mixture composition and said at least one useful parameter defining the target final composition. Thus, and advantageously, the calculation unit makes it possible to make priority choices on the precision of one of the useful parameters compared to others. In this way, it is possible to implement the preparation method in the case where there is no unique or exact mathematical solution for the preparation of cooling water having a composition close to the target final composition.

[0034] According to one embodiment, each of the first composition, the second composition, the mixture composition, and the target final composition is defined by a plurality of useful parameters, the calculation step can then be implemented by weighting each useful parameter of said plurality of useful parameters by a weighting coefficient.

[0035] According to one embodiment, the mixing phase comprises:

[0036] - a step of controlling the mixture composition, in which an intermediate value of said at least one useful parameter defining the mixture composition is determined, so as to calculate an initial difference between said intermediate value and a target value of said at least one useful parameter defining the target final composition

[0037] - in the case where the initial deviation is greater than a threshold deviation, the mixing phase comprises a second mixing step in which at least one correction element chosen from the group consisting of a volume of the industrial water solution, a volume of the water solution treated on a cationic ion exchanger, a volume of the demineralized water solution, a volume of the aqueous solution containing Mg ions 2+ and that 2+ , a mass of salt, and a mass of pH correctors, is mixed with the mixing solution so as to produce a corrected mixing volume of a corrected mixing solution characterized by a corrected mixing composition which is defined by at least one useful parameter, said at least one correction element being chosen so that a corrected deviation between a corrected value of said at least one useful parameter defining the corrected mixing composition and said target value is less than the initial deviation.

[0038] According to one embodiment, the second mixing step is implemented as long as the corrected deviation is greater than the threshold deviation. According to one embodiment, the control step comprises determining the corrected deviation. According to one embodiment, the threshold deviation may be equal to 10% of the target value.

[0039] According to one embodiment, at least one mixing step among the first mixing step and the second mixing step is implemented so as to maintain the corrected mixing solution at a temperature between 10°C and 35°C, preferably between 12°C and 30°C.

[0040] According to one embodiment, the preparation method further comprises a step of providing at least one addition element chosen from the group comprising salts and pH correctors, the first mixing step further comprising mixing a mass of addition element, said mass of addition element being determined as a function of the first composition and the second composition, and of the target final composition.

[0041] According to one embodiment, the salts and pH adjusters comprise: sodium chloride NaCl, sodium bicarbonate NaHCOs, sodium carbonate Na2CO3, calcium chloride CaCL, magnesium sulfate MgSO4, magnesium chloride MgCL, and sodium bromide NaBr.

[0042] According to one embodiment, the mass of additive element is diluted in an aqueous solution before the first mixing step during a dilution step. For example, the mass of additive element may be diluted in a portion of the demineralized water solution.

[0043] According to one embodiment, the water solution treated on a cationic ion exchanger is decarbonated water obtained according to the following steps:

[0044] - a step of providing a cation exchanger comprising a weak cationic resin, said cation exchanger being configured to vary between a regenerated configuration in which said weak cationic resin is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg 2+ and a charged configuration in which said weak cationic resin constitutes a reserve of divalent calcium cations Ca 2+ or magnesium Mg 2+ ;

[0045] - a weak cationic resin loading step in which part of the industrial water solution circulates in the cation exchanger to vary it from the regenerated configuration to the loaded configuration;

[0046] - a degassing step in which water leaving the cation exchanger is degassed, so as to obtain decarbonated water.

[0047] According to one embodiment, said weak cationic resin is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg 2+bound to carbonate or bicarbonate ions. In this case, the degassing step comprises the degassing of water loaded with dissolved carbonic acid (originating from calcium and magnesium carbonates and bicarbonates) leaving the cation exchanger. According to one embodiment, the degassing step is carried out naturally, leaving the water leaving the cation exchanger in the open air. According to one embodiment, the degassing step is carried out in a degassing column. According to one embodiment, the degassing step is carried out by subjecting the water leaving the cation exchanger to successive cascades, or by stirring, agitation, bubbling, or by using a trickle degassing column into which air is injected in countercurrent.

[0048] According to one embodiment, the water solution treated on a cationic ion exchanger is a permuted water obtained according to the following steps:

[0049] - a step of providing a cation exchanger comprising a strong cationic resin, said cation exchanger being configured to vary between a regenerated configuration in which said strong cationic resin is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg 2+ and a charged configuration in which said strong cationic resin constitutes a reserve of divalent calcium cations Ca 2+ or magnesium Mg 2+ ;

[0050] - a loading step on strong cationic resin in which part of the industrial water solution circulates in the cation exchanger to vary it from the regenerated configuration to the loaded configuration, and so as to obtain the permuted water, free of Ca2+ and Mg2+ cations.

[0051] According to one embodiment, said strong cationic resin is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg2+bound to carbonate or bicarbonate ions. The use of strong cationic resin to obtain the water solution treated on a cationic ion exchanger is advantageous in the case where the industrial water solution is not very calcareous and of low alkalinity. It is possible to use a salt regeneration method (softener type) or a dilute strong acid regeneration method (cations completely exchanged by H3O+ ions). In the case where a salt regeneration method is used, such as NaCl or Na2SO4, the exchanged water can also be called "softened water". Softened water is water in which the Ca2+ and Mg2+ cations have been replaced by Na+ from the resin. In the case where a dilute strong acid regeneration method is used, the exchanged water can also be called "water whose cations are all exchanged by hydronium ions H^O+". This water is water in which the Ca2+ and Mg2+ cations have been replaced by hydronium ions H3O+ from the resin.

[0052] According to one embodiment, the step of charging on weak or strong cationic resin comprises a step of detecting the charge level, in which a measurement of the variation of the pH or of another parameter of the water present at the outlet of the cation exchanger is carried out, so as to deduce therefrom (for example for future cycles) the charge level of the cation exchanger at any time.

[0053] According to one embodiment, the demineralized water solution is obtained by a demineralization step in which a portion of the decarbonated water or permuted water solution is demineralized by a reverse osmosis or ion exchange process on a demineralization resin so as to obtain the demineralized water solution. The demineralization process conventionally comprises a permutation operation on a strong cationic resin, degassing and an anion permutation operation on one or two anionic resins (depending on the composition of the water and in particular its alkalinity). Preferably, if permuted water obtained by a dilute strong acid regeneration technique is used, the permutation step on a cationic resin is not necessary to obtain the demineralized water.

[0054] According to one embodiment, the aqueous solution containing Mg ions 2+ and that 2+is obtained during an elution step in which a strong acid is circulated in the cation exchanger, so that Mg ions 2+ and that 2+ captured by the weak cationic resin or by the strong cationic resin are dissolved, so as to produce the aqueous solution containing Mg ions 2+ and that 2+ .

[0055] According to one embodiment, the elution step comprises a measuring step in which a pH of the aqueous solution containing Mg ions 2+ and that 2+is measured, so as to optimize the quantity of acid used, and so as to optimize the regeneration of the cation exchanger. According to one embodiment, a quantity of strong acid added during the elution step is defined in relation to a volume of weak or strong cationic resin to be treated. Such a quantity of strong acid may for example be part of the technical data of the cationic resin used, said data specifying the volume and concentration of strong acid necessary to regenerate said cationic resin.

[0056] According to one embodiment, the aqueous solution containing Mg ions 2+ and that 2+is obtained by withdrawing a partial quantity of the solution obtained during the elution step. For example, such a partial quantity may correspond to a quantity of water produced at the beginning of the elution step. In this case, the remainder of the water produced during the elution step, necessary for the regeneration of the cation exchanger, is then treated and rejected. In this way, it is possible to control and limit the excess of strong acid with the aqueous solution containing Mg ions 2+ and that 2+ when the weak or strong cationic resin is completely regenerated. According to one embodiment, the strong acid is hydrochloric acid or sulfuric acid, preferably diluted between 2 and 10% in water. In the case where the strong acid is sulfuric acid, the aqueous solution containing Mg ions 2+ and that 2+ obtained in the elution step contains dissolved CaSO4 and MgSO4 salts.

[0057] According to one embodiment, the elution step is carried out after the loading step on weak cationic resin or after the loading step on strong cationic resin. It is therefore well understood that the elution and loading steps make it possible to alternately vary the cation exchanger between the regenerated configuration and the loaded configuration.

[0058] According to one embodiment, the preparation method further comprises a second analysis step in which at least one useful parameter of the industrial water solution selected from the group comprising a calcium concentration, a magnesium concentration, a complete alkalimetric titer, an alkalimetric titer, a hydrotimetric titer, and a pH is measured.

[0059] According to one embodiment, the second analysis step can be implemented to determine a useful parameter of the water solution treated on a cationic ion exchanger, or on the demineralized water solution, or on the aqueous solution containing Mg ions. 2+ and that 2+ .

[0060] The provisions previously described make it possible to choose the aqueous solution(s) having the most suitable composition to serve as a basis for the manufacture of a mixing solution having a mixing composition which tends towards the target final composition.

[0061] The aim of the invention can also be achieved by the use of cooling water obtained according to the preparation method described above, and characterized by said target final composition, to cool a product in a metallurgical transformation step, such as casting, quenching, or hot rolling.

[0062] The aim of the invention can also be achieved by implementing a method for casting a product, preferably made of aluminum alloy, comprising the following steps:

[0063] - (a) a bath of liquid metal is prepared, preferably made of an aluminium alloy comprising, in % by weight, Cu: 0 - 6.0; Mg: 0- 8; Si 0-12; Zn 0 - 12; others < 3 each and < 10 in total, remainder aluminium,

[0064] - (b) said liquid metal is cast, preferably by vertical semi-continuous casting in such a way that, during a casting start-up phase, a first cooling water characterized by a first mixture composition obtained according to the preparation method described above is used.

[0065] The casting method according to the invention comprises the preparation method defined above.

[0066] Said first cooling water characterized by a first mixture composition is obtained by a preparation process comprising the following steps:

[0067] - a step of analyzing the composition of a target cooling water so as to determine a target final composition,

[0068] - a step of providing at least one first aqueous solution characterized by a first composition and at least one second aqueous solution distinct from the first aqueous solution and characterized by a second composition, said first aqueous solution and said second aqueous solution being chosen from the group consisting of:

[0069] . of an industrial water solution,

[0070] . of a water solution treated on a cationic ion exchanger,

[0071] . of a solution of demineralized water,

[0072] . of an aqueous solution containing Mg ions 2+ and that2+ ,

[0073] - a mixing phase comprising a first mixing step in which a first volume of the first aqueous solution and a second volume of the second aqueous solution are mixed, so as to produce a mixing volume of a mixing solution characterized by a mixing composition, and constituting all or part of the cooling water, said first volume of the first aqueous solution and second volume of the second aqueous solution being determined as a function of said first composition and said second composition, each of the first composition (cl), the second composition (c2), the mixing composition (cml), and the target final composition (cfc), is defined by at least one useful parameter chosen from the group comprising a calcium concentration (THCa), a magnesium concentration (THMg), a total alkalimetric titer (TAC), an alkalimetric titer (TA), a hydrotimetric titer (TH),a concentration of chloride ions (CCI), sulfates (CS), bromides (CBr), sodium (CNa) and a pH,

[0074] - a calculation step (E7) in which the first volume (VI) of the first aqueous solution and the second volume (V2) of the second aqueous solution are determined as a function of said at least one useful parameter defining the first composition (cl), of said at least one useful parameter defining the second composition (c2), and so that said at least one useful parameter defining the mixture composition (cml) tends towards said at least one useful parameter defining the target final composition (cfc).

[0075] The preparation process may further have one or more characteristics presented previously.

[0076] The casting process may further have one or more of the following characteristics, taken alone or in combination.

[0077] According to one embodiment, the casting method comprises a steady-state casting phase at the end of the casting start-up phase, characterized in that during the steady-state casting phase, a second cooling water is used, characterized by a second composition, different from the first cooling water. Optionally, this second cooling water is obtained according to the preparation method. Optionally, this second composition is a second mixture composition obtained according to the preparation method. According to another embodiment, the second cooling water is not obtained according to the preparation method of the invention; it may be an industrial water solution.

[0078] Finally, the aim of the invention can also be achieved by implementing a casting device comprising a device for preparing cooling water, said preparation device comprising a mixing unit configured to receive a first aqueous solution characterized by a first composition and a second aqueous solution distinct from the first aqueous solution and characterized by a second composition, said first aqueous solution and said second aqueous solution being chosen from the group consisting of:

[0079] - an industrial water solution,

[0080] - a water solution treated on a cationic ion exchanger,

[0081] - a solution of demineralized water,

[0082] - an aqueous solution containing Mg ions 2+ and that 2+, said mixing unit being further configured to mix a first volume of said first aqueous solution and a second volume of said second aqueous solution, so as to manufacture a mixing volume of a mixing solution characterized by a mixing composition and constituting all or part of the cooling water, said first volume of the first aqueous solution and second volume of the second aqueous solution being determined as a function of said first composition and said second composition, and so that the mixing composition tends towards a predetermined target final composition.

[0083] The casting device may further have one or more of the following features, taken alone or in combination.

[0084] According to one embodiment, the mixing unit is configured to mix a number of volumes of aqueous solutions greater than or equal to two.

[0085] According to one embodiment, the preparation device comprises at least one reservoir chosen from:

[0086] - a first tank configured to receive the industrial water solution;

[0087] - a second tank configured to receive the water solution treated on a cationic ion exchanger;

[0088] - a third tank configured to receive the demineralized water solution;

[0089] - a fourth reservoir configured to receive the aqueous solution containing Mg ions 2+ and that 2+ .

[0090] According to one embodiment, the use of the first tank, the second tank, the third tank, and the fourth tank can be replaced by a continuous in-line mixing process. By continuous in-line mixing process is meant the possibility of carrying out the mixing of the aqueous solutions directly in a piping system, feed or by inserting a static mixer or low volume mixing reactor.

[0091] According to one embodiment, the mixing unit is further configured to receive at least one addition element selected from the group comprising salts and pH correctors, and to mix a mass of addition element with the mixing solution, said mass of addition element being determined as a function of the first composition, the second composition, and the target final composition.

[0092] According to one embodiment, the preparation device further comprises an addition element storage unit configured to store said at least one addition element. According to one embodiment, the casting device further comprises a calculation unit configured to determine the first volume of the first aqueous solution and the second volume of the second aqueous solution as a function of a useful parameter defining the first composition, a useful parameter defining the second composition, and such that a useful parameter defining the mixture composition tends towards a useful parameter defining the target final composition.

[0093] According to one embodiment, the casting device further comprises a cation exchanger comprising an active material, said cation exchanger being configured to vary between a charged configuration in which divalent calcium cations Ca 2+ or magnesium Mg2+ are bound to the active material, and a regenerated configuration in which the active material is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg 2+ , said cation exchanger comprising means for connecting it to the mixing unit. According to one embodiment, the cation exchanger comprises a weak cationic resin. According to one embodiment, the cation exchanger comprises a strong cationic resin.

[0094] According to one embodiment, the cation exchanger comprises means for connecting it to at least one reservoir, for example the first reservoir, the second reservoir, the third reservoir, or the fourth reservoir.

[0095] According to one embodiment, the casting device further comprises a reverse osmosis unit or an ion exchanger on demineralization resin, said reverse osmosis unit or said ion exchanger comprising means for connecting it to the mixing unit and to the cation exchanger.

[0096] According to one embodiment, said reverse osmosis system or said ion exchanger on demineralization resin comprises means allowing it to be connected to at least one tank, for example the first tank, the second tank, the third tank, or the fourth tank.

[0097] According to one embodiment, the preparation device comprises a strong acid supply, said strong acid supply being configured to be connected to the cation exchanger.

[0098] According to one embodiment, the casting device further comprises an analysis unit configured to measure at least one useful parameter selected from the group comprising: a calcium concentration, a magnesium concentration, a complete alkalimetric titer, an alkalimetric titer, a hydrotimetric titer, and pH.

[0099] According to one embodiment, the mixing unit comprises a temperature control system comprising a temperature sensor configured to measure a mixing temperature corresponding to the temperature of the mixing solution, said temperature control system being configured to maintain the mixing temperature between 10°C and 35°C, preferably between 12°C and 30°C. According to one embodiment, the temperature control system comprises heating means configured to heat the mixing unit, when the mixing temperature is less than or equal to 10°C, preferably less than 12°C.

[0100] According to one embodiment, the temperature control system comprises cooling means configured to cool the mixing unit, when the mixing temperature is greater than or equal to 35°C, preferably 30°C.

[0101] Description of figures

[0102] Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the appended drawings in which: [Fig. 1] Figure 1 is a schematic view of the casting device comprising a preparation device according to a particular embodiment of the invention.

[0103] [Fig. 2] Figure 2 is a schematic view of certain elements of the casting device for preparing aqueous solutions, according to a particular embodiment of the invention.

[0104] [Fig. 3] Figure 3 is a schematic view of the steps of the preparation method according to a particular embodiment of the invention.

[0105] Detailed description

[0106] In the figures and in the remainder of the description, the same references represent identical or similar elements. In addition, the different elements are not shown to scale so as to enhance the clarity of the figures. Furthermore, the different embodiments and variants are not mutually exclusive and can be combined with each other.

[0107] As illustrated in Figures 1 to 3, the present invention relates to a method for preparing cooling water 1 intended to cool a product during a metallurgical transformation operation and in particular for casting applications of foundry parts. The invention also relates to the use of cooling water 1 obtained according to this preparation method, to cool a product in a metallurgical transformation step, such as casting, quenching, or hot rolling. Unlike continuous casting, where the concept of a start-up step is not preponderant with regard to the quality of the final product because it is possible to trim the part of the product with defects, it is important to control the cooling during the start-up phase of a product obtained by semi-continuous casting at the risk of not being able to manufacture it.In semi-continuous casting, the difficulty lies in successfully transitioning from the zero speed at the start of product formation to the steady-state speed. This is called the start-up phase. This transition results in a deformation of the slab foot, known to those skilled in the art as camber. If it is too pronounced, which occurs when the foot is cooled too violently, the camber can cause what those skilled in the art call "creases", which can sometimes degenerate into "hanging", i.e. jamming of the slab in its mold. Camber combined with an unsuitable cooling regime can lead, less catastrophically, to breakage of the foot or cracks in the foot.These breaks or cracks are quite harmful because they can propagate in a steady state, thus leading to the rejection of the product. Otherwise, and at the very least, they prevent the hot rolling of the plate without sawing the foot to restore the integrity of the product. Finally, a camber that does not result in any casting rejects, however, results in variations in the product section that can prevent the rolling of products without sawing the foot.

[0108] Those skilled in the art know how to implement suitable casting conditions to minimize the occurrence of these defects. However, it is important that the conditions found are reproducible from one casting to the next. The inventors found that in particular it was important to have reproducible cooling water during all start-up phases in order to guarantee the same thermal efficiency. The inventors solved this problem by proposing a method for preparing cooling water that makes it possible to produce a target cooling water on demand.

[0109] For example, the target cooling water may correspond to industrial water available at a site where the casting process will be implemented on a large scale, this site being different from the production site envisaged for the implementation of the cooling water preparation. For example, the target cooling water may correspond to industrial water available during a certain period of the year. This is the case, for example, when the industrial water of a site is drawn from a river and its composition changes depending on the summer / winter seasonality. It may be interesting to choose to always have identical industrial water regardless of the season. The target cooling water may be water considered suitable for the start of casting due to its energy efficiency quality.

[0110] Figure 1 shows a process for casting a product, preferably made of aluminum alloy, which comprises the following steps:

[0111] - (a) a bath of liquid metal is prepared, preferably made of an aluminium alloy comprising, in % by weight, Cu: 0 - 6.0; Mg: 0- 8; Si 0-12; Zn 0 - 12; others < 3 each and < 10 in total, remainder aluminium, and

[0112] - (b) said liquid metal is cast, preferably by vertical semi-continuous casting in such a way that, during a solidification start-up phase, a first cooling water 1a is used, characterized by a first mixture composition cma obtained according to the preparation method according to the invention which will be described more precisely below.

[0113] Preferably, an aluminum alloy of the AAlxxx or AA2xxx or AA3xxx or AA4xxx or AA5xxx or AA6xxx or AA7xxx series is cast.

[0114] By way of non-limiting examples, examples of AAlxxx series aluminum alloys for use in the methods described herein may include AA1100, AA1100A, AA1200, AA1200A, AA1300, AA1110, AA1120, AA1230, AA1230A, AA1235, AA1435, AA1145, AA1345, AA1445, AA1150, AA1350, AA1350A, AA1450, AA1370, AA1275, AA1185, AA1285, AA1385, AA1188, AA1190, AA1290, AA1193, AA1198 or AA1199.

[0115] Non-limiting examples of AA2xxx series aluminum alloys for use in the methods described herein may include AA2001, A2002, AA2004, AA2005, AA2006, AA2007, AA2007A, AA2007B, AA2008, AA2009, AA2010, AA2011, AA2011A, AA2111, AA2111A, AA2111B, AA2012, AA2013, AA2014, AA2014A, AA2214, AA2015, AA2016, AA2017, AA2017A, AA2117, AA2018, AA2218, AA2618, AA2618A, AA2219, AA2319, AA2419, AA2422, AA2422A, AA2422B, AA2422C, AA2422D, AA2422E, AA2422F, AA2422G, AA2422H ... AA24,20 AA2124, AA2224, AA2224A, AA2324, AA2424, AA2524, AA2624, AA2724, AA2824, AA2025, AA2026, AA2027, AA2028, AA2028A, AA2028B, AA2028C, AA2029, AA2030, AA2031, AA2032, AA2034, AA2036, AA2037, AA2038, AA2039, AA2139, AA2040, AA2041, AA2044, AA2045, AA2050, AA2055, AA2056, AA2060, AA2065, AA2070, AA2076, AA2090, AA2091, AA2094, AA2095, AA2195, AA2295, AA2196, AA2296, AA2097, AA2197, AA2297, AA2397, AA2098, AA2198, AA2099, or AA2199.

[0116] Examples of non-limiting AA3xxx series aluminum alloys for use in the methods described herein may include AA3002, AA3102, AA3003, AA3103, AA3103A, AA3103B, AA3203, AA3403, AA3004, AA3004A, AA3104, AA3204, AA3304, AA3005, AA3005A, AA3105A, AA3105B, AA3007, AA3107, AA3207, AA3207A, AA3307, AA3009, AA3010, AA3110, AA3011, AA3012, AA3012A, AA3013, AA3014, AA3015, AA3016, AA3017, AA3018, AA3019, AA3020, AA3021, AA3022, AA3023, AA3024, AA3025, AA3026, AA3027, AA3028, AA3029, AA3030, AA3031, AA3032, AA3033, AA3034, AA3035, AA3036, AA3037, AA3038, AA3039, AA3040, AA3041, AA3042, AA3043, AA3044, AA3045, AA3046, AA3047, AA3048, AA3049, AA3050, AA3051, AA3052, AA3053, AA3054, AA3055, AA3056, AA3057, AA3058, AA3059, AA3060, AA3061, AA3062, AA3063, AA3064, AA30 or AA3065.

[0117] Non-limiting examples of AA4xxx series aluminum alloys for use in the methods described herein may include AA4004, AA4104, AA4006, AA4007, AA4008, AA4009, AA4010, AA4013, AA4014, AA4015, AA4015A, AA4115, AA4016, AA4017, AA4019, AA4020, AA4021, AA4026, AA4032, AA4043, AA4043A, AA4143, AA4343, AA4643, AA4943, AA4044, AA4045, AA4145, AA4145A, AA4046, AA4047, AA4047A, or AA44. Non-limiting examples of aluminum alloys of the AA5xxx series for use in the methods described herein may include AA5182, AA5183, AA5005, AA5005A, AA5205, AA5305, AA5505, AA5605, AA5006, AA5106, AA5010, AA5110, AA5110A, AA5210, AA5310, AA5016, AA5017, AA5018, AA5018A, AA5019, AA5019A, AA5119, AA5119A, AA5021, AA5022, AA5023, AA5024, AA5026, AA5027, AA5028, AA5040, AA5140, AA5041, AA5042, AA5043, AA5049, AA5149, AA5249, AA5349, AA5449, AA5449A, AA5050, AA5050A, AA5050C, AA5150, AA5051, AA5051A, AA5151, AA5251, AA5251A, AA5351, AA5451, AA5052, AA5252, AA5352, AA5154, AA5154A, AA5154B,AA5154C, AA5254, AA5354, AA5454, AA5554, AA5654, AA5654A, AA5754, AA5854, AA5954, AA5056, AA5356, AA5356A, AA5456, AA5456A, AA5456B, AA5556, AA5556A, AA5556B, AA5556C, AA5257, AA5457, AA5557, AA5657, AA5058, AA5059, AA5070, AA5180, AA5180A, AA5082, AA5182, AA5083, AA5183, AA5183A, AA5283, AA5283A, AA5283B, AA5383, AA5483, AA5086, AA5186, AA5087, AA5187, or AA5088.,

[0118] Non-limiting examples of AA6xxx series aluminum alloys for use in the methods described herein may include AA6101, AA6101 A, AA6101B, AA6201, AA6201A, AA6401, AA6501, AA6002, AA6003, AA6103, AA6005, AA6005A, AA6005B, AA6005C, AA6105, AA6205, AA6305, AA6006, AA6106, AA6206, AA6306, AA6008, AA6009, AA6010, AA6110, AA6110A, AA6011, AA6111, AA6012, AA6012A, AA6013, AA6113, AA6014, AA6015, AA6016, AA6016A, AA6116, AA6018, AA6019, AA6020, AA6021, AA6022, AA6023, AA6024, AA6025, AA6026, AA6027, AA6028, AA6031, AA6032, AA6033, AA6040, AA6041, AA6042, AA6043, AA6151, AA6351, AA6351A, AA6451, AA6951, AA6053, AA6055, AA6056, AA6156, AA6060, AA6160, AA6260, AA6360, AA6460, AA6460B, AA6560, AA6660, AA6061, AA6061A, AA6261, AA6361, AA6162, AA6262, AA6262A, AA6063, AA6063A, AA6463, AA6463A, AA6763, AA6963, AA6064, AA6064A, AA6065, AA6066, AA6068, AA6069, AA6070, AA6081, AA6181, AA6181A, AA6082, AA6082A, AA6182, AA6091, or AA6092.

[0119] Examples of non-limiting AA7xxx series aluminum alloys for use in the methods described herein may include AA7011, AA7019, AA7020, AA7021, AA7039, / K7O1 , AA7075, AA7085, AA7108, AA7108A, AA7015, AA7017, AA7018, AA7019A, AA7024, AA7025, AA7028, AA7030, AA7031, AA7033, AA7035, AA7035A, AA7046, AA7046A, AA7003, AA7004, AA7005, AA7009, AA7010, AA7011, AA7012, AA7014, AA7016, AA7116, AA7122, AA7023, AA7026, AA7029, AA7129, AA7229, AA7032, AA7033, AA7034, AA7036, AA7136, AA7037, AA7040, AA7140, AA7041, AA7049, AA7049A, AA7I49,72O4, AA7249, AA7349, AA7449, AA7050, AA7050A, AA7150, AA7250, AA7055, AA7155, AA7255, AA7056, AA7060, AA7064, AA7065, AA7068, AA7168, AA7175, AA7475, AA7076, AA7178, AA7278, AA7278A, AA7081, AA7181, AA7185, AA7090, AA7093, AA7095, or AA7099.As illustrated in the non-limiting example of Figure 1, the casting process may comprise a steady-state phase c at the end of the casting start-up phase, characterized in that during the steady-state casting phase c, a second cooling water is used. The second cooling water lb is characterized by a second target final composition cfb. For example, this second cooling water lb may also be obtained according to the preparation method which will be described in more detail below. Alternatively, the second cooling water lb may correspond to an industrial water solution 3.

[0120] Figures 1 to 3 represent a non-limiting example of a preparation method according to a particular embodiment of the invention.

[0121] The preparation method comprises a first step of analysis E1 of the composition of a target cooling water 1. This analysis step makes it possible to determine a final target composition CFC. Generally, according to the invention, the determination of a composition corresponds to the determination of at least one useful parameter chosen from the group comprising a calcium concentration THCa, a magnesium concentration THMg, a complete alkalimetric titer TAC, an alkalimetric titer TA, a hydrotimetric titer TH, a concentration of chloride ions CCI, sulfates CS, bromides CBr, sodium CNa, and a pH.Thus the final target CFC composition, determined by the first analysis step El, makes it possible to define at least one useful target parameter chosen from the group comprising a calcium concentration THCa, a magnesium concentration THMg, a complete alkalimetric titer TAC, an alkalimetric titer TA, a hydrotimetric titer TH, a concentration of chloride ions CCI, sulfates CS, bromides CBr, sodium CNa, and a pH.

[0122] The preparation method also comprises a step E6 of providing at least one first aqueous solution characterized by a first composition c1 and at least one second aqueous solution distinct from the first aqueous solution and characterized by a second composition c2, said first aqueous solution and said second aqueous solution being chosen from the group consisting of:

[0123] - an industrial water solution 3,

[0124] - a water solution treated on a cationic ion exchanger 5,

[0125] - a solution of demineralized water 7,

[0126] - an aqueous solution containing Mg ions 2+ and that 2+ 9.

[0127] In the same way as for the final target composition cfc, the first composition cl, and the second composition c2 are defined by at least one useful parameter pul and pu2 chosen from the group comprising a calcium concentration THCa, a magnesium concentration TH Mg, a complete alkalimetric titer TAC, an alkalimetric titer TA, a hydrotimetric titer TH, a concentration of chloride ions CCI, sulfates CS, bromides CBr, sodium CNa, and a pH. Said at least one useful parameter pul and pu2 defined are of the same nature as said at least one target useful parameter pue. The compositions cl and c2 are different.

[0128] Preferably, the industrial water solution 3 is characterized by a conductivity of between 100 pS / cm and 2000 pS / cm.

[0129] Preferably, the water solution treated on cationic ion exchangers 5 is decarbonated water, preferably decarbonated water with a conductivity greater than or equal to 100 pS / cm and a hydrotimetric title TH in French degrees (°f) and a complete alkalimetric title TAC in French degrees (°f) such as TH <TAC + 3°f. De manière préférée, la solution d'eau traitée sur échangeurs d'ions cationiques 5 est une eau permutée, de préférence une eau permutée avec une conductivité supérieure ou égale à 100 pS / cm et un titre hydrotimétrique TH en degré français (°f) tel que TH < 3°f.

[0130] Preferably, the demineralized water 7 has a conductivity of less than 100 pS / cm.

[0131] Preferably, the aqueous solution containing Mg ions 2+ and that 2+has a conductivity greater than or equal to 20 pS / cm and a hydrotimetric title TH in French degrees (°f) such that TH > 50 °f.

[0132] According to the invention, in one embodiment, the first aqueous solution and the second aqueous solution may both be an industrial water solution or a cationic ion exchanger treated water solution or an aqueous solution containing Mg ions. 2+ and that 2+ , the compositions cl and c2 being however different.

[0133] Figure 2 illustrates more specifically different ways of obtaining the four solutions mentioned above.

[0134] The industrial water solution 3 corresponds, for example, to water present on an industrial site on which the preparation process that is the subject of the invention is implemented. It is possible that this industrial site is a site separate from the industrial site on which the target cooling water is available. For example, the target cooling water may correspond to industrial water available on a site on which the casting process will be implemented on a large scale. The industrial water solution 3 may, for its part, correspond to industrial water present on an industrial site for developing the casting process. The industrial water solution 3 may also be derived from pumping from the water table, then treated by various steps such as iron removal, and / or filtration, and / or red-ox stabilization, to be stable and usable for the industrial needs of the site.The industrial water solution 3 may also come from a basin allowing the recycling of water by cooling (for example using a cooling tower or a refrigeration unit). Thus, it may therefore be advantageous for the preparation method to comprise a second analysis step E2 in which at least one useful parameter of said industrial water solution 3 chosen from the group comprising a calcium concentration THCa, a magnesium concentration THMg, a complete alkalimetric titer TAC, an alkalimetric titer TA, a hydrotimetric titer TH, a concentration of chloride ions CCI, sulfates CS, bromides CBr, sodium CNa, and a pH is measured. The useful parameter analyzed in the analysis step E2 is of the same nature as said at least one target useful parameter. By "of the same nature" is meant that if the hydrotimetric titer TH is chosen to define the final target CFC composition, the hydrotimetric titer TH of the industrial water 3 is determined.Such a second analysis step E2 can also be implemented to determine at least one useful parameter of the water solution treated on a cationic ion exchanger 5, and / or to determine at least one useful parameter of the demineralized water solution 7, and / or to determine at least one useful parameter of the aqueous solution containing Mg ions. 2+ and that 2+ 9. Thus, it is possible to choose the aqueous solution(s) having the most suitable composition to serve as a basis for the manufacture of a mixture solution having a cml mixture composition which tends towards the final target cfc composition.

[0135] In the remainder of the description, when reference is made to "aqueous solutions", this includes the group consisting of industrial water solution 3, cationic ion exchanger treated water solution 5, demineralized water solution 7, and aqueous solution containing Mg ions. 2+ and that2+ 9.

[0136] The water solution treated on cationic ion exchanger 5 can be obtained using two methods described below.

[0137] According to a first non-limiting variant, the water solution treated on a cationic ion exchanger 5 is decarbonated water obtained according to the following steps:

[0138] - a step E30 of providing a cation exchanger 20 comprising a weak cationic resin 21, said cation exchanger 20 being configured to vary between a regenerated configuration in which said weak cationic resin 21 is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg 2+ and a charged configuration in which said weak cationic resin 21 constitutes a reserve of divalent calcium cations Ca 2+ or magnesium Mg 2+ ;

[0139] - a loading step on weak cationic resin E32 in which a part of the industrial water solution 3 circulates in the cation exchanger 20 to vary it from the regenerated configuration to the loaded configuration;

[0140] - a degassing step E34 in which water leaving the cation exchanger 20 is degassed, so as to obtain decarbonated water. The degassing step E34 can for example be implemented naturally, by leaving the water leaving the cation exchanger 20 in the open air. Alternatively, the degassing step E34 can be implemented in a degassing column 24. According to a third possibility, the degassing step E34 can be implemented by subjecting the water leaving the cation exchanger 20 to successive cascades, or by mixing, stirring, bubbling, or by using a trickle degassing column 24 into which air is injected in countercurrent.

[0141] Preferably, the decarbonated water has a conductivity greater than or equal to 100 pS / cm and a hydrotimetric title TH in French degrees (°f) and a complete alkalimetric title TAC in French degrees (°f) such as TH <TAC + 3°f.

[0142] According to a second non-limiting variant, the water solution treated on a cationic ion exchanger 5 is an exchanged water obtained according to the following steps:

[0143] - a step E31 of providing a cation exchanger 20 comprising a strong cationic resin 23, said cation exchanger 20 being configured to vary between a regenerated configuration in which said strong cationic resin 23 is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg 2+ and a charged configuration in which said strong cationic resin 23 constitutes a reserve of divalent calcium cations Ca 2+ or magnesium Mg 2+ ;

[0144] - a strong cationic resin charging step E33 in which a portion of the industrial water solution 3 circulates in the cation exchanger 20 to vary it from the regenerated configuration to the charged configuration, and so as to obtain the permuted water. According to one embodiment, the charging step E32, E33 comprises a charging level detection step, in which a measurement of variation in the pH or another parameter of the water present at the outlet of the cation exchanger 20 is carried out, so as to deduce therefrom (for example for future cycles) the charging level of the cation exchanger 20 at any time.

[0145] Preferably, permuted water with a conductivity greater than or equal to 100 pS / cm and a hydrotimetric title TH in French degrees (°f) such that TH < 3°f.

[0146] In the case where the industrial water solution 3 is not very calcareous, it is advantageous to obtain the water solution treated on a cationic ion exchanger 5 by a cation exchanger 20 using an active material with strong cationic resin 23.

[0147] The demineralized water solution can be obtained by any method known from the state of the art. According to the principle of the invention, in a preferred embodiment, the demineralized water solution 7 can be obtained by a demineralization step E41 in which a portion of the decarbonated water or permuted water solution is demineralized by a reverse osmosis process T1 or ion exchange on a series of demineralization resins (cationic / anionic) 25 so as to obtain the demineralized water solution 7.

[0148] According to one embodiment, the demineralized water solution 7 can be obtained by a charging step E33 so as to exchange the cations with Hydronium ions H3O+ on the strong cationic resin, followed by a demineralization step E41 on resins 25 in which a portion of the water whose cations are already exchanged with H3O+ will be treated simply on a series of anionic resins 25. A preliminary degassing can be carried out before passing over anionic resins 25.

[0149] Preferably, the demineralized water 7 has a conductivity of less than 100 pS / cm. Finally, the aqueous solution containing Mg ions 2+ and that 2+ 9 is obtained during an elution step E43 in which a strong acid 11 is circulated in the cation exchanger 20, so that Mg ions 2+ and that 2+captured by the weak cationic resin 21 or by the strong cationic resin 23 are dissolved, so as to produce the aqueous solution containing Mg ions 2+ and that 2+ 9. Generally, strong acid 11 is hydrochloric acid or dilute sulfuric acid preferably at a concentration between 2 and 10% in water. In the particular case where strong acid 11 is sulfuric acid, the aqueous solution containing Mg ions 2+ and that 2+ 9 obtained in elution step E43 also contains dissolved CaSO4 and MgSO4 salts. These salts are particularly interesting to obtain because they avoid the use of addition elements containing sulfur. Indeed, this aqueous solution containing Mg ions 2+ and that 2+9 contains CaSO4 and MgSO4 salts and is obtained directly from industrial water and an acid. This avoids the need to supply salts such as calcium sulfate (CaSO4) or magnesium sulfate (MgSO4). On the other hand, we know in particular that calcium sulfate, commonly called "plaster" in everyday language, has very low solubility in water and its dissolution is complex and difficult.

[0150] Advantageously, the elution step E43 is carried out after the charging step E32, E33. It is therefore well understood that the elution steps E43, and the charging steps E32, E33, make it possible to alternately vary the cation exchanger 20 between the regenerated configuration and the charged configuration.

[0151] According to one embodiment, the elution step E43 may comprise a measurement step E45 in which a pH of the aqueous solution containing Mg ions 2+ and that 2+9 is measured. Indeed, the elution step E43 being implemented by the circulation of a strong acid in the cation exchanger 20, it is possible to find traces of strong acid 11 in the aqueous solution containing Mg ions 2+ and that 2+ 9, which can help lower its pH. In order to better control the composition of the aqueous solution containing Mg ions 2+ and that 2+9, it is therefore preferable to guarantee the absence of the strong acid 11 in this solution. To avoid this, it is possible to provide that a quantity of strong acid 11 added during the elution step E43 is defined in relation to a volume of weak 21 or strong 23 cationic resin to be treated. Such a quantity of strong acid 11 may for example be part of the technical data of the cationic resin 21, 23 used, said data specifying the volume and the concentration of strong acid 11 necessary to regenerate said cationic resin 21, 23. In this way, it is possible to prevent the mixing of the strong acid 11 with the aqueous solution containing Mg ions 2+ and that 2+9 when the weak cationic resin 21 or strong cationic resin 23 is completely regenerated. Alternatively, the measuring step E45 can be implemented by measuring a parameter other than the pH, such as for example the measurement of the conductivity. In this way, it is possible to know and control a possible excess of strong acid 11 during the elution step E43.

[0152] Preferably, the aqueous solution containing Mg ions 2+ and that 2+ has a conductivity greater than or equal to 20 pS / cm and a hydrotimetric title TH in French degrees (°f) such that TH > 50 °f.

[0153] With reference to Figure 1, the preparation method may further comprise a step E51 of providing at least one addition element chosen from the group comprising salts 13 and pH correctors 15. The salts 13 and pH correctors 15 may in particular comprise: sodium chloride NaCl, sodium bicarbonate NaHCOs, sodium carbonate Na2CO3, calcium chloride CaCL, magnesium sulfate MgSO4, magnesium chloride MgCL, and sodium bromide NaBr. A mass denoted “m” of addition elements may then be diluted in an aqueous solution during a dilution step E53 to form an addition solution. For example, the mass m of addition element may be diluted in a portion of the demineralized water solution 7. In the case where several addition elements are added, it is possible to produce several addition solutions, each corresponding to a diluted addition element.In this case, several masses mj corresponding to each addition element j are diluted in an aqueous solution.

[0154] Referring again to the providing step E6, it is understood that this step E6 of providing the first aqueous solution and the second aqueous solution is not limiting and that it may also comprise the provision of a number of volumes of distinct aqueous solutions greater than two. Thus, the providing step E6 may comprise the provision of a third or a fourth aqueous solution chosen distinct from each other and distinct from the first aqueous solution and the second aqueous solution, said third or fourth aqueous solutions being chosen from the group consisting of:

[0155] - industrial water solution 3, water solution treated on cationic ion exchanger 5, demineralized water solution 7, aqueous solution containing Mg ions 2+ and that2+ 9.

[0156] The preparation method may then comprise a calculation step E7 in which a first volume VI of the first aqueous solution and a second volume V2 of the second aqueous solution are determined as a function of said at least one useful parameter pul defining the first composition cl, and of said at least one useful parameter pu2 defining the second composition c2. In the case where salts 13 and pH correctors 15 are made available during step E51, the calculation step E7 also aims to determine the mass m of addition element as a function of the first composition cl, the second composition c2, and the final target composition cfc.As indicated previously, the determination of a first volume VI of a first aqueous solution, and of a second volume V2 of a second aqueous solution is not limiting, and the calculation step E7 can also comprise the determination of a third volume V3 of a third aqueous solution characterized by a third composition c3, and of a fourth volume V4 of a fourth aqueous solution characterized by a fourth composition c4.These volumes VI, V2, V3, and V4 of aqueous solutions, and this mass m are intended to be mixed during a mixing phase P3 which will be described later, and so as to produce a mixing volume Vml of a mixing solution characterized by a mixing composition cml which can also be defined by at least one useful parameter puml chosen from the group comprising a calcium concentration THCa, a magnesium concentration THMg, a complete alkalimetric titer TAC, an alkalimetric titer TA, a hydrotimetric titer TH, a concentration of chloride ions CCI, sulfates CS, bromides CBr, sodium CNa, and a pH.

[0157] The calculation step E7 therefore aims to determine the volumes of aqueous solution VI, V2, V3, and V4, and the mass m so that said at least one useful parameter puml defining the mixture composition cml tends towards said at least one useful parameter pue defining the target final composition cfc. It is therefore well understood that depending on the calculation step, the volumes VI, V2, V3, or V4 may be zero and that the mass m may be zero.

[0158] For example, according to a first non-limiting variant, the calculation step E7 makes it possible to determine the first volume VI of the first aqueous solution determined by at least one first useful parameter pul of the same nature as the at least one target useful parameter pue and the second volume V2 of the second aqueous solution determined by at least one second useful parameter pu2 of the same nature as the at least one target useful parameter pue. The calculation step may consist of solving the following equation system: pul*Vl +pu2*V2=puc*Vml

[0159] Vml=Vl+V2

[0160] In the case where several useful target parameters are determined for the final target CFC composition, the calculation method described consists of solving as many systems of equations as there are determined target useful parameters.

[0161] In this case, it is advantageous to use a 30 computing unit.

[0162] According to one embodiment, the calculation step E7 is implemented by a calculation unit 30 configured to calculate the first volume VI of the first aqueous solution and the second volume V2 of the second aqueous solution so as to minimize a difference between said at least one useful parameter defining the mixture composition cml and said at least one useful parameter defining the target final composition cfc. In the case where the target final composition cfc is defined by several parameters, there are sometimes no solutions for VI and V2 making it possible to solve the system. Advantageously, the calculation unit 30 makes it possible to make priority choices on the precision of one of the useful parameters compared to others.In this way, it is possible to implement the preparation method in the case where there is no unique or exact mathematical solution for the preparation of cooling water 1 having a composition close to the final target CFC composition.

[0163] According to one embodiment, each of the first composition cl, the second composition c2, the mixture composition cml, and the final target composition cfc, is defined by a plurality of useful parameters, the calculation step E7 can then be implemented by weighting each useful parameter of said plurality of useful parameters by a weighting coefficient.

[0164] According to one embodiment, the calculation step E7 can be implemented by comparing each useful parameter with another useful parameter of the same type. For example, according to another non-limiting variant, the calculation step E7 makes it possible to determine the first volume VI of the first aqueous solution and the second volume V2 of the second aqueous solution by comparing the complete alkalimetric titer TAC of the first aqueous solution, the complete alkalimetric titer TAC of the second aqueous solution, and the complete alkalimetric titer TAC of the cooling water 1. Thus, each useful parameter can be compared with another useful parameter of the same type during the calculation step E7.

[0165] The preparation method finally comprises the mixing phase P3 comprising a first mixing step E8 in which the first volume VI of the first aqueous solution and the second volume V2 of the second aqueous solution are mixed, so as to produce the mixing volume Vml of a mixing solution characterized by a mixing composition cml. This mixing solution then constitutes all or part of the cooling water 1.

[0166] It is well understood that said first volume VI of the first aqueous solution and second volume V2 of the second aqueous solution are determined during the calculation step E7, as a function of said first composition cl and said second composition c2, and so that the mixture composition cml tends towards the predetermined target final composition cfc.

[0167] As in the supply step E6, the mixing phase P3 is not limited to the first volume VI of the first aqueous solution and the second volume V2 of the second aqueous solution and may also comprise the mixing of a number of volumes of distinct aqueous solutions greater than two. For example, the supply step E6 may comprise the mixing of the third and / or the fourth aqueous solution with the first and the second aqueous solution. Furthermore, the first mixing step E8 may also comprise the mixing of the mass m of addition element, itself also determined during the calculation step E7.Thus, and according to a particular embodiment, the cooling water 1 can be obtained by a mixture of four volumes VI, V2, V3, V4 of aqueous solutions, each volume of aqueous solution coming respectively from the industrial water solution 3, the water solution treated on a cationic ion exchanger 5, the demineralized water solution 7, and the aqueous solution containing Mg ions. 2+ and that 2+ 9, and the mass m of addition element.

[0168] The mixing phase P3 may then comprise a step E9 of controlling the cml mixture composition, in which an intermediate value of said at least one useful parameter defining the cml mixture composition is determined, so as to calculate an initial difference between said intermediate value and a target value of said at least one useful parameter defining the final target composition cfc. The control step E9 therefore makes it possible to determine the difference between the useful parameters of the cml mixture composition and the corresponding useful parameters of the final target composition cfc. In other words, the control step E9 makes it possible to quantify whether the cml mixture composition is sufficiently close to the final target composition cfc.

[0169] In the case where the initial deviation is greater than a threshold deviation, i.e. when the mixture composition cml is too far from the target final composition cfc, the mixing phase may comprise a second mixing step E10 in which at least one correction element is mixed with the mixing solution so as to produce a corrected mixing volume Vm2 of a corrected mixing solution characterized by a corrected mixing composition cm2 which is defined by at least one useful parameter. This correction element is Tl chosen from the group consisting of a volume of the industrial water solution 3, a volume of the water solution treated on a cationic ion exchanger 5, a volume of the demineralized water solution 7, a volume of the aqueous solution containing Mg ions 2+ and that 2+ 9, of a mass ml of salt 13, and of a mass m2 of pH correctors 15.

[0170] Naturally, the correction element is chosen so that a corrected deviation between a corrected value of said at least one useful parameter defining the corrected mixture composition cm2 and said target value is less than the initial deviation.

[0171] According to one embodiment, it may be provided that the control step E9 comprises the determination of the corrected deviation, and that the second mixing step E10 is implemented iteratively as long as the corrected deviation is greater than the threshold deviation. For example, the threshold deviation may be equal to 10% or 5% or 3% of the target value.

[0172] Generally, it may also be provided that at least one mixing step among the first mixing step E8 and the second mixing step E10 is implemented so as to maintain the corrected mixing solution at a temperature between 10°C and 35°C, preferably between 12°C and 30°C.

[0173] The provisions previously described make it possible to propose a method for preparing cooling water 1 having a composition close to a final target CFC composition. Furthermore, and advantageously, the use of the aqueous solution containing Mg ions 2+ and that 2+ 9 makes it easier to produce, on demand, cooling water 1 having a composition close to the final target CFC composition.

[0174] According to the invention, the aqueous solution containing Mg ions 2+ and that 2+ is such that the concentration of Mg ions 2+ and that 2+ is greater than the concentration of Mg ions 2+ and that 2+ industrial water solution, cationic ion exchange treated water solution, or demineralized water solution.

[0175] As indicated previously, the preparation method and the casting method can be implemented by means of a casting device 100, the subject of the invention.

[0176] The casting device, shown in Figure 1, comprises a device 50 for preparing cooling water 1. The preparation device 50 may in particular comprise at least one reservoir chosen from:

[0177] - a first tank 33 configured to receive the industrial water solution 3;

[0178] - a second reservoir 35 configured to receive the water solution treated on a cationic ion exchanger 5;

[0179] - a third reservoir 37 configured to receive the demineralized water solution 7;

[0180] - a fourth reservoir 39 configured to receive the aqueous solution containing Mg ions 2+ and that 2+9. The embodiment of Figure 1 shows a preparation device 50 comprising four reservoirs.

[0181] According to an embodiment not shown, the use of the first reservoir 33, the second reservoir 35, the third reservoir 37, and the fourth reservoir 39 can be replaced by a continuous in-line mixing method. By continuous in-line mixing method is meant the possibility of carrying out the mixing of the aqueous solutions directly in a piping or supply system.

[0182] The casting device 100 may further comprise a cation exchanger 20 (FIG. 2) comprising an active material, said cation exchanger 20 being configured to vary between a charged configuration in which divalent calcium cations Ca 2+ or magnesium Mg 2+are bound to the active material, and a regenerated configuration in which the active material is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg 2+ , said cation exchanger 20 comprising means for connecting it to the mixing unit 31 not shown. The active material may comprise either a weak cationic resin 21 or a strong cationic resin 23. As illustrated in FIG. 2, the cation exchanger 20 is included in the preparation device 50. In order to be able to simply implement the preparation method, the cation exchanger 20 may comprise means for connecting it to at least one reservoir, for example the first reservoir 33, the second reservoir 35, the third reservoir 37, or the fourth reservoir 39. These means may for example comprise pipes for carrying out a fluid transfer to and from the cation exchanger 20.

[0183] The casting device 100 may also comprise a reverse osmosis unit 27 or an ion exchanger on demineralization resin 25, said reverse osmosis unit 27 or said ion exchanger comprising means for connecting it to a mixing unit 31 and to the cation exchanger 20, not shown. In general, the reverse osmosis unit T1 or said ion exchanger on demineralization resin 25 comprises means for connecting it to at least one reservoir, for example the first reservoir 33, the second reservoir 35, the third reservoir 37, or the fourth reservoir 39. In the variant illustrated in FIG. 2, the reverse osmosis unit T1 comprises means for connecting it fluidically to the second reservoir 35, and to the third reservoir 37.

[0184] The preparation device 50 may comprise a strong acid supply 41 configured to be connected to the cation exchanger 20, and an addition element storage unit 32 configured to store at least one addition element selected from the group comprising salts 13 and pH correctors 15. Referring again to FIG. 1, the first reservoir 33, the second reservoir 35, the third reservoir 37, the fourth reservoir, and the storage unit 32 are fluidically connected to a mixing unit 31.

[0185] The mixing unit 31 is configured to receive the first aqueous solution characterized by the first composition c1 and the second aqueous solution distinct from the first aqueous solution and characterized by the second composition c2, said first aqueous solution and said second aqueous solution being chosen from the group consisting of:

[0186] - industrial water solution 3,

[0187] - the water solution treated on a cationic ion exchanger 5,

[0188] - demineralized water solution 7,

[0189] - the aqueous solution containing Mg ions 2+ and that 2+ 9.

[0190] The mixing unit 31 is further configured to mix a first volume VI of said first aqueous solution and a second volume V2 of said second aqueous solution, so as to produce a mixing volume Vml of a mixing solution characterized by a mixing composition cml and constituting all or part of the cooling water 1.

[0191] Said first volume VI of the first aqueous solution and second volume V2 of the second aqueous solution being determined as a function of said first composition cl and said second composition c2, and so that the mixture composition cml tends towards a predetermined target final composition cfc. As shown in FIG. 1, the mixing unit 31 may be configured to mix a number of volumes of aqueous solutions greater than two. The mixing unit 31 is further configured to receive and to mix a mass m of addition element with the mixture solution, said mass m of addition element being determined as a function of the first composition cl, the second composition c2, and the target final composition cfc.

[0192] According to a particular embodiment, the mixing unit 31 comprises a temperature control system 61 comprising a temperature sensor 63 configured to measure a mixing temperature corresponding to the temperature of the mixing solution. The temperature control system 61 is then configured to maintain the mixing temperature between 10°C and 35°C, preferably between 12°C and 30°C. The temperature control system 61 may be provided with heating means 65 configured to heat the mixing unit 31, when the mixing temperature is less than or equal to 10°C or 12°C. The temperature control system 61 may also comprise cooling means 67 configured to cool the mixing unit 31, when the mixing temperature is greater than or equal to 35°C or 30°C.In addition, the casting device 100 may advantageously comprise an analysis unit 60 configured to measure at least one useful parameter chosen from the group comprising: a calcium concentration THCa, a magnesium concentration THMg, a complete alkalimetric titer TAC, an alkalimetric titer TA, a hydrotimetric titer TH, and the pH. The analysis unit 60 may in particular be used to implement the first analysis step E1 and the second analysis step E2 of the preparation method.

[0193] Finally, the casting device 100 may comprise a calculation unit 30 configured to determine the first volume VI of the first aqueous solution and the second volume V2 of the second aqueous solution as a function of a useful parameter defining the first composition cl, of a useful parameter defining the second composition c2, and so that a useful parameter defining the mixture composition cml tends towards a useful parameter defining the target final composition cfc. In general, the calculation unit is capable of implementing the calculation step E7 according to the embodiments described above and below. The preparation method and its implementation with the casting device 100 may be better understood on the basis of the examples given below, given as a non-limiting example.

[0194] Example 1:

[0195] In this example, a cooling water 1 is prepared based on a target industrial water. Table 1 below describes the composition of the industrial water solution 3 which may for example correspond to the first composition cl, and the final target composition cfc obtained during the first analysis step El, and the second analysis step E2.

[0196] ^Table 1]

[0197] In this example, the industrial water solution 3 characterized by the composition cl, has a high hardness, a high alkalinity and a high chloride ion content. This industrial water solution 3 can be stored in a first tank 33.

[0198] A portion of the industrial water solution 3 can then undergo a charging step E32 when it circulates in the cation exchanger comprising a weak cationic resin 21 (the RESINEX KW-H resin, from the company Jacobi Carbons, Sweden). During this charging step E32, the industrial water solution 3 circulates with a flow rate of 5m 3 / h, then on a degasser during the degassing step E34. The degasser comprises a trickle column with countercurrent air flow which is located above a second tank 35. In this second tank, the solution of water treated on a cationic ion exchanger 5 is thus obtained, which is then decarbonated water having, in this example, a second composition c2.

[0199] The second tank 35 may comprise means which allow it to be fluidically connected to a reverse osmosis unit T1, in order to be able to supply the third tank 37 with demineralized water. According to this example, the reverse osmosis unit T1 comprises nine membranes and operates with a purge rate of 25%. This reverse osmosis unit T1 is capable of producing between 1 m 3 / h and 2m 3 / h of the demineralized water solution 7 during the demineralization step E41. Said demineralized water solution then has a composition c3 which is stored in a third tank 37.

[0200] When the weak resin 21 of the cation exchanger 20 is sufficiently charged during the charging step E32, the elution step E43 is carried out so as to produce the aqueous solution containing Mg ions. 2+ and that 2+9 having a fourth composition c4, a part of which will be stored in a fourth reservoir 39. For example, the elution step E43 can be implemented when a percentage of charge of the low resin 21 compared to the theoretical saturation calculated for the cation exchanger is between 60% and 90% of the saturation.

[0201] According to one embodiment, the elution step E43 comprises:

[0202] - a backwashing step in which industrial water 3 is introduced counter-currently, this backwashing step making it possible to lift the resin grains and eliminate accumulated impurities, typically a water flow rate of at least 5 m3 / h is used

[0203] - an elution step with a 4% sulfuric acid solution, this solution itself being prepared by diluting a 20% commercial sulfuric acid solution with demineralized water using a metering pump. This step makes it possible to produce the aqueous solution containing Mg ions 2+ and that 2+ 9.

[0204] - a slow rinsing step (piston flow of the liquid) with demineralized water 7 in order to circulate part of the aqueous solution containing Mg ions 2+ and that 2+ 9 to tank 39, and

[0205] - a rapid rinsing step (turbulent flow of the liquid) with demineralized water solution 7, consisting of rapidly eliminating traces of acid 11 which would still be present.

[0206] In the particular case of this example, the use of weak cationic resins 21 makes it possible to obtain effluents of relatively low acidity which are simply neutralized by passing over a bed of calcium carbonate granules. Any water which is not used for the production of the tapping water (1, 1a or 1b), residues, part of the unused acid solution, rinsings) is considered to be acid effluent. As indicated previously, the industrial water solution 3 has a first composition cl determined during the second analysis step E2. This first composition cl of this industrial water solution 3 can be sufficiently stable over time so as not to require additional second analysis steps E2.

[0207] In the particular case of this first example, the second, third, and fourth compositions c2, c3, and c4 can be deduced knowing the first composition of cl, as follows:

[0208] The water solution treated on cationic ion exchanger 5 is obtained by decarbonation on a weak cationic resin 21. The Na cations + (sodium), Ca 2+ (calcium) and Mg 2+ (magnesium) bound to the salts of strong acids (sulfates and chlorides) are not retained and will end up in the water solution treated on cationic ion exchanger 5 by passing through cation exchanger 20, as well as all the anions (carbonates, bicarbonates). The cations retained by cation exchanger 20 (Mg 2+ and that 2+ bound to carbonates and bicarbonates) will be retained on the weak cationic resin 21 and replaced by hydronium ions HsO + (2 HsO ions + by Ca ion 2+ or by Mg ion 2+ ). We therefore calculate the second composition c2 in calcium and magnesium ions, in this case, from the total hydrotimetric TH title according to the following formula:

[0209] TH (of the second composition c2) = TH (of the first composition cl) - TAC (of the first composition cl).

[0210] We therefore obtain TH=3.1°f (41.1-38.0).

[0211] The calcium (THCa) and magnesium (THMg) values ​​are calculated assuming that the same ratio (here THCa / THMg=5) is maintained as in the industrial water solution. Therefore, THCa and THMg are calculated in the water solution treated on a cationic ion exchanger 5 by solving equations (1) and (2):

[0212] (1) THCa / THMg=5

[0213] (2) THCa + THMg = TH = 3.1

[0214] By solving this system, we then obtain the values ​​in table 2 below (THMg=0.5°f, and THCa=2.6°f, rounded values).

[0215] The TAC, obtained after the degasser, was measured at 0.5°f at the degasser outlet. This value is stable and is not measured at each mixture.

[0216] The demineralized water solution having the third composition c3 is produced by demineralizing the treated water solution on a cationic ion exchanger 5 during the demineralization step E41. It is possible to analyze the third composition c3 during a third analysis step consisting of measuring the conductivity of the solution. This third analysis step makes it possible to determine that the main ions have a concentration lower than 5 mg / L, except for sodium and chlorides (approximately 5 mg / L).

[0217] The fourth composition c4 of the aqueous solution containing Mg ions 2+ and that 2+9 depends on the acid concentration 11 used for the regeneration of the weak cationic resin 21. For this example, the elution efficiency of the cation exchanger used, estimated at 0.98, is taken into account. The value of 0.98 corresponds to the elution efficiency of the cation exchanger used. The concentration of calcium and magnesium ions (from which TH is calculated) then corresponds, at the start of elution step E43, to 0.98 times the concentration (in moles or in °f) of sulfuric acid. This sulfuric acid concentration can be controlled by acid and water flow rate measurements, and an online conductivity measurement. It may be planned to keep only the eluate from the start of elution step E43, and within the capacity of the fourth tank 39. According to this protocol, the aqueous solution containing Mg ions 2+ and that 2+9 therefore has a fourth constant composition c4 which can be determined only once by implementing the second analysis step E2 on the aqueous solution containing Mg ions 2+ and that 2+ 9.

[0218] Table 2]

[0219] The following relationships exist between TH, THCa, THMg and R = THCa / THMg.

[0220] TH = THCa + THMg

[0221] THCa = R.TH / (1+R)

[0222] THMg = TH / (1+R)

[0223] The steps E51 of providing at least one addition and dilution element E53 make it possible to form addition solutions of composition a1, a2, a3, a4, and a5 corresponding to the dilution of the mass ml of salt, or the mass m2 of pH corrector in a volume of demineralized water solution 7 so as to provide an addition solution of MgSO4 (at 10%) defined by a composition a1, an addition solution of MgCL (at 10%) defined by a composition a2, an addition solution of NaHCOs (at 8%) defined by a composition a3, and an addition solution of NaOH (at 5%) defined by a composition a4. The 20% sulfuric acid solution used to regenerate the cation exchangers 20 is stored in a 3m3 tank. It can also serve as an addition solution defined by a composition a5.

[0224] The chemical compositions a1, a2, a3, a4, and a5 of the addition solutions are described with the same formalism as the four previous aqueous solutions, the TH parameters and the ratio R= THCa / THMg being replaced by THCa and THMg, to avoid divergent calculations when THCa = 0, or THMg = 0.

[0225] ^Table 3]

[0226] From the available aqueous solutions of compositions cl, c2, c3, and c4, the final target composition cfc, and the chemical compositions of the addition solutions al, a2, a3, a4, and a5, it is possible to implement the calculation step E7.

[0227] The mixture composition cml of the mixing solution, for a volume Vml (known), is then described by the following equation, which is broken down for each useful parameter of each composition (for example THCa, THMg, TAC, Sodium, Chlorides, Sulfates). We therefore obtain in this case, 6 equations corresponding to 6 different useful parameters: ci.Vml = Vl.cli + V2.c2i + V3.c3i + V4.c4i + Val.ali + Va2.a2i + Va3.a3i + Va4.a4i + Va5.a5i.

[0228] The subscript i in the previous formula refers to the 6 useful parameters described in this example (THCa, THMg, TAC, CNa, CCI, CS).

[0229] We have Vml=Vl+V2+V3+V4+Val+Va2+Va3+Va4+Va5, where VI, V2, V3, and V4 correspond to the volumes to be mixed of aqueous solutions of compositions cl, c2, c3, and c4 and Val, Va2, Va3, Va4, and Va5 correspond to the volumes to be mixed of addition solutions of composition al, a2, a3, a4, a5.

[0230] In the case of this first example, the following parameters Vml and cli, c2i, c3i, c4i, ali, a2i, a3i, a4i, a5i are known:

[0231] - Vml corresponds to the volume of cooling water to be produced. It is also possible to use flow rates by dividing the volumes by a unit of time. This parameter is defined by a single value. For this example, we need 24m 3 of cooling water solution. This flow rate value is 2.4m 3 / h if the characteristic time is 100 (time interval between each pour for example).

[0232] - cli, c2i, c3i, c4i, ali, a2i, a3i, a4i, a5i: correspond respectively to the useful parameters of the available aqueous solutions (3, 5, 7, 9), and of the available salt addition solutions 13 and pH correctors 15. Additional analysis steps can possibly be implemented to control each useful parameter.

[0233] According to a non-limiting variant, a weighting coefficient yi can be used to prioritize one of the useful parameters. In this example, for example, greater importance is given to the magnesium concentration THMg compared to the sodium concentration CNa or the sulfate ion concentration CS. The following weighting coefficients yi are therefore chosen, making it possible to obtain the following cml mixture composition (Table 4):

[0234] ^Table 4]

[0235] In the context of this example and the chosen weightings, it is possible to obtain a mixture solution having a mixture composition cml equal to the final target composition cfc. However, such a solution is not always mathematically obtained given the elements available during the preparation process.

[0236] Calculation step E7 then includes determining the volumes to be mixed. In this example, the unknowns are the 9 volumes of the solutions to be mixed (VI, V2, V3, V4, Val, Va2, Va3, Va4, Va5). The calculation unit 30 then uses a solver that minimizes the following sum of the deviations:

[0237] Zi=i =>6 Yi. [(VI. cl, + V2.C2, + V3.c3i + V4.c4, + Val.al, + Va2.a2, + Va3.a3, + Va4.a4, + Va5.a5i ) - Vml.cmli ] 2

[0238] In order to obtain mathematical solutions that make physical sense, desired boundary conditions are added (i.e. all values ​​are positive, volumes cannot be greater than the capacity of tanks 33, 35, 37, 39) so as to obtain the volumes of each solution to be added, as well as the mixture composition cml of the mixing solution.

[0239] In the context of this particular example, a volume Vml of 24 m3 of the mixing solution can be obtained by mixing the following volumes:

[0240] - VI (industrial water solution 3) = 9.28m 3

[0241] - V2 (water solution treated on cationic ion exchanger 5) = 9.10m 3

[0242] - V3 (demineralized water solution 7) = 2.64m 3

[0243] - V4 (aqueous solution containing Mg2+ and Ca2+ ions 9) = 2.98m 3

[0244] And with the following additives:

[0245] Val (10% MgSO4 solution) = 21.7L

[0246] Va2 (10% CaCI2 solution) = 13.3L

[0247] Va3, Va4 and Va5 are not used (=0). The mixing phase P3 then comprises only a first mixing step E8 by mixing in a mixing unit 31 the calculated volumes corresponding to the different solutions. For example, the first mixing step E8 of the aqueous solutions can be carried out in the following order: VI, V2, V3, V4, by means of a magnetic stirrer, then by adding the volumes of addition solutions Val and Va2 while maintaining stirring. The preparation method can then comprise the control step E9 in which a control of the mixture composition cml obtained is carried out. This control comprises:

[0248] - measurement of the hydrotimetric rate TH and the complete alkalimetric rate TAC using a TH and TAC analyzer with color indicator

[0249] - pH measurement using a pH probe.

[0250] Depending on the result of control step E9, the pH can then be corrected by adding bleach to obtain a desired amount of free chlorine so that the cml mixture composition tends towards the final target cfc composition.

[0251] Example 2:

[0252] In this second example, Table 5 below describes the composition of the industrial water solution which may, for example, correspond to the first composition cl, and also describes the final target composition cfc. These two compositions are obtained during the first analysis step E1, and the second analysis step E2. In particular, in the implementation of the preparation method of this example, the aim is to obtain a cooling water 1 for which the useful parameters "hydrotimetric rate and complete alkalimetric rate TAC" are lower than the corresponding useful parameters of the final target composition cfc.

[0253] Table 5]

[0254] According to this example, the preparation device 50 comprises a reverse osmosis unit T1, connected to the first tank 33, but does not comprise a cation exchanger 20. It is therefore only possible to produce two aqueous solutions characterized by two compositions:

[0255] - the industrial water solution 3 characterized by the first composition cl; and

[0256] - the demineralized water solution 7 characterized by a second composition c2.

[0257] The industrial water solution 3, for example stored in the first tank 33, or available directly on site, feeds the reverse osmosis unit T1, which makes it possible to produce the demineralized water solution 7 by the demineralization step E41 of a portion of the industrial water solution 3, then to store it in the third tank 37.

[0258] Advantageously, the industrial water solution 3 used to produce the demineralized water solution 7 is filtered by a filter having a filtration mesh of 5 μm. This prevents fouling of the membranes (particularly at the spacers) and increases their lifespan. Advantageously, a polyphosphate-based sequestering product is continuously injected. This prevents precipitation of calcium ions in the presence of carbonates in the concentration loop of the reverse osmosis system 27.

[0259] In the context of this example, the industrial water solution 3 stored in the first tank 33 may have a composition cl which varies depending in particular on the devices using this water, the season, and the operation of the temperature control system 61. Thus, it may be planned to implement one or more second analysis steps E2 in order to know at each instant a good estimate of the first composition cl of this stored industrial water solution 3.

[0260] Unlike industrial water solution 3, demineralized water solution 7 has a substantially constant and known composition c2. It is therefore not necessary to carry out a second analysis step E2 at each demineralization step E41. An online conductivity check is sufficient to ensure the correct operation of the reverse osmosis unit and the constant quality of the water. Table 6 below lists the first and second compositions cl, c2 of industrial water solutions 3 and demineralized water 7.

[0261] Table 6]

[0262] From the available aqueous solutions and the final target CFC composition, it is possible to implement calculation step E7. In this example, it is not possible to use aqueous solutions other than those mentioned above, nor to use addition elements.

[0263] The mixture composition of the mixture solution cml, for a volume Vml (known), is then described by the following equation, which is broken down for each useful parameter of each composition (for example THCa, THMg, TAC, Sodium, Chlorides, Sulfates). We therefore obtain in this case 6 equations corresponding to 6 different useful parameters: ci.Vml = Vl.cli + V2.c2i,

[0264] The index i refers to the 6 useful parameters described in this example (THCa, THMg, TAC, CNa, CCI, CS), with Vml=Vl+ V2. In the case of this first example, the following parameters are known:

[0265] - Vml: volume of solution to be manufactured;

[0266] - cli, c2i: which correspond respectively to the useful parameters of the available aqueous solutions (3, 7),

[0267] According to a non-limiting variant, a weighting coefficient yi can be used to prioritize one of the useful parameters. In this example, for example, greater importance is given to the magnesium concentration THMg and the calcium concentration THCA compared to the other useful parameters. The following weighting coefficients yi are therefore chosen, making it possible to obtain the following cml mixture composition (Table 7):

[0268] ^Table 7]

[0269] The calculation step E7 therefore then includes the determination of the volumes to be mixed. In this example, the unknowns are the 2 volumes of the aqueous solutions to be mixed VI, V2. The calculation unit 30 then uses a solver which makes it possible to minimize the following sum of the deviations:

[0270] Zi= 1 =>6 yi. [(VI. cl, + V2.c2i) - Vml.cmli ] 2

[0271] In order to obtain real solutions, desired boundary conditions are added. For example, all values ​​are positive, volumes cannot be greater than the capacity of tanks 33, 37 so as to obtain the volumes of each solution to be added as well as the mixture composition cml of the mixing solution.

[0272] In this particular case, given the available aqueous solutions, it is not possible to obtain exactly the target final cfc composition. It is nevertheless possible to obtain a volume of mixing solution Vml respecting the objectives set for the preparation process by choosing to mix half and half the industrial solution 3 (Vl = 50% Vml) and the demineralized solution 7 (V2 = 50% Vml).

Claims

CLAIMS A process for preparing cooling water (1) for cooling a product during a metallurgical processing operation, particularly for semi-continuous casting applications of foundry products, the preparation process comprising the following steps: - an analysis step (El) of the composition of a target cooling water in order to determine a final target composition (cfc), - a supply step (E6) of at least one first aqueous solution characterized by a first composition (c1) and at least one second aqueous solution distinct from the first aqueous solution and characterized by a second composition (c2), said first aqueous solution and said second aqueous solution being chosen from the group composed of: . of an industrial water solution (3) with a conductivity less than or equal to 2000 pS / cm and a total hardness less than or equal to 80 °f, . of a water solution treated on a cationic ion exchanger (5) with a conductivity greater than or equal to 100 pS / cm, which is either decarbonated water such as TH5 <TAC5+ 3°f, soit une eau permutée telle TH5< 3 °f, où TH5et TAC5sont respectivement le titre hydrotimétrique et le titre alcalimétrique de la solution d'eau traitée sur échangeur d'ions cationiques (5) considérée exprimés en degré français °f, . of a demineralized water solution (7) with a conductivity less than or equal to 100 pS / cm, . of an aqueous solution containing Mg ions 2+ and that 2+ (9), with a conductivity greater than or equal to 20 pS / cm, such that its total hardness THg is greater than 50 °f, - a mixing phase (P3) comprising a first mixing step (E8) in which a first volume (VI) of the first aqueous solution and a second volume (V2) of the second aqueous solution are mixed, so as to produce a mixing volume (Vml) of a mixing solution characterized by a mixing composition (cml), and constituting all or part of the cooling water (1), said first volume (VI) of the first aqueous solution and second volume (V2) of the second aqueous solution being determined by a calculation step (E7) as a function of said first composition (cl) and said second composition (c2), and in which each of the first composition (cl), the second composition (c2), the mixing composition (cml), and the final target composition (cfc) is defined by at least one useful parameter chosen from the group including calcium concentration (THCa), magnesium concentration (THMg), total alkalimetric titration (TAC), alkalimetric titration (TA), total hardness (TH), concentration of chloride ions (CCI), sulfates (CS), bromides (CBr), sodium (CNa) and pH; - said calculation step (E7) in which the first volume (VI) of the first aqueous solution and the second volume (V2) of the second aqueous solution are determined as a function of said at least one useful parameter defining the first composition (c1), said at least one useful parameter defining the second composition (c2), and such that said at least one useful parameter defining the mixture composition (c1m) tends towards said at least one useful parameter defining the target final composition (c1m). Preparation method according to claim 1, wherein the calculation step (E7) is implemented by a calculation unit (30) configured to calculate the first volume (VI) of the first aqueous solution and the second volume (V2) of the second aqueous solution so as to minimize a difference between said at least one useful parameter defining the mixture composition (c1m) and said at least one useful parameter defining the target final composition (c1m).A preparation process according to claim 1 or 2, further comprising a step of providing (E51) at least one additive selected from the group comprising salts (13) and pH adjusters (15), the first mixing step (E8) further comprising mixing a mass (m) of additive, said mass (m) of additive being determined according to the first composition (c1) and the second composition (c2), and the final target composition (cfc). A preparation process according to any one of claims 1 to 3, wherein the water solution treated on a cation exchanger (5) is decarbonated water obtained according to the following steps: - a supply step (E30) of a cation exchanger (20) comprising a weak cationic resin (21), said cation exchanger (20) being configured to vary between a regenerated configuration in which said weak cationic resin (21) is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg 2+ and a charged configuration in which said weak cationic resin (21) constitutes a reservoir of divalent calcium cations Ca 2+ or magnesium Mg 2+ ; - a weak cationic resin charging stage (E32) in which part of the industrial water solution (3) circulates in the cation exchanger (20) comprising the weak cationic resin (21) to vary it from the regenerated configuration to the charged configuration; - a degassing step (E34) in which water exiting the cation exchanger (20) is degassed, so as to obtain decarbonated water such as TH5 <TAC5+ 2°f où TH5et TAC5sont respectivement le titre hydrotimétrique et le titre alcalimétrique de la solution décarbonatée exprimés en degré français. Procédé de préparation selon l'une quelconque des revendications 1 à 3, dans lequel la solution d'eau traitée sur échangeur d'ions cationiques (5) est une eau permutée, obtenue selon les étapes suivantes : - a supply step (E31) of a cation exchanger (20) comprising a strong cationic resin (23), said cation exchanger (20) being configured to vary between a regenerated configuration in which said strong cationic resin (23) is capable of capturing divalent calcium cations Ca 2+ or magnesium Mg 2+and a charged configuration in which said strong cationic resin (23) constitutes a reservoir of divalent calcium cations Ca 2+ or magnesium Mg 2+ ; - a charging stage on a strong cationic resin (E33) in which a portion of the industrial water solution (3) circulates through the cation exchanger (20) comprising the strong cationic resin (23) to change it from the regenerated configuration to the charged configuration, and so as to obtain the permutated water such as TH5 <TAC5 où TH5et TAC5sont respectivement le titre hydrotimétrique et le titre alcalimétrique de la solution permutée exprimés en degré français. Procédé de préparation selon l'une quelconque des revendications 4 ou 5 dans lequel la solution d'eau déminéralisée (7) est obtenue par une étape de déminéralisation (E41) dans laquelle une partie de la solution d'eau décarbonatée ou d'eau permutée est déminéralisée par un processus d'osmose inverse ou d'échange d'ions sur une résine de déminéralisation (25) de manière à obtenir la solution d'eau déminéralisée (7) de conductivité inférieure ou égale à 100 pS / cm.A preparation method according to any one of claims 4 to 6, wherein the aqueous solution containing Mg ions. 2+ and that 2+ (9) is obtained during an elution step (E43) in which a strong acid (11) is circulated in the cation exchanger (20), so that Mg ions 2+ and that 2+ captured by the weak cationic resin (21) or by the strong cationic resin (23) are dissolved, so as to produce the solution aqueous containing Mg ions 2+ and that 2+ (9) of conductivity greater than or equal to 20 pS / cm, such that its total hardness THg is greater than 50 °f.

8. A preparation method according to claim 7 in which the strong acid (11) is sulfuric acid.

9. Preparation process according to claim 7 or 8, wherein the elution step (E43) is carried out after the loading step on weak cationic resin (E32) or after the loading step on strong cationic resin (E33).

10. Use of a cooling water (1) obtained according to the preparation process of any one of claims 1 to 9 for cooling a product in a metallurgical transformation step, such as casting, quenching, or hot rolling.

11. A method for casting a product, preferably made of aluminum alloy, comprising the following steps: (a) a liquid metal bath is prepared, preferably an aluminium alloy comprising, in % by weight, Cu: 0 - 6.0; Mg: 0 - 8; Si: 0 - 12; Zn: 0 - 12; other < 3 each and < 10 in total, remainder aluminium, (b) said liquid metal is poured by vertical semi-continuous pouring such that, during a pouring start-up phase, a first cooling water (la) is used, characterized by a first mixture composition (cma) obtained according to the preparation process according to any one of claims 1 to 9.

12. Casting process according to claim 11 comprising a steady-state casting phase (c) following the casting start-up phase and such that during the steady-state casting phase (c), a second cooling water (lb) is used, characterized by a second composition (cfb), different from the first cooling water (la), optionally this second cooling water (lb) is obtained according to the preparation process according to any one of claims 1 to 9.

13. Casting device (100) comprising a cooling water preparation device (50), said preparation device (50) comprising: - an analysis unit (60) configured to measure at least one useful parameter chosen from the group comprising: calcium concentration (THCa), magnesium concentration (THMg), total alkalimetric titration (TAC), alkalimetric titration (TA), total hardness (TH), and pH, - a calculation unit (30) configured to determine the first volume (VI) of the first aqueous solution and the second volume (V2) of the second aqueous solution as a function of a useful parameter defining the first composition (cl), a useful parameter defining the second composition (c2), and such that a useful parameter defining the mixture composition (cml) tends towards a useful parameter defining the final target composition (cfc) - a cation exchanger (20) comprising an active material, said cation exchanger (20) being configured to vary between a charged configuration in which divalent calcium cations Ca 2+ or magnesium Mg 2+ are linked to the active material, and a regenerated configuration in which the active material is able to capture divalent calcium cations Ca 2+ or magnesium Mg 2+ said cation exchanger (20) comprising means for connecting it to the mixing unit (31), preferably said cation exchanger (20) comprising a weak cationic resin (21) or a strong cationic resin (23) - a mixing unit (31) configured to receive a first aqueous solution characterized by a first composition (c1) and a second aqueous solution distinct from the first aqueous solution and characterized by a second composition (c2), said first aqueous solution and said second aqueous solution being chosen from the group composed: - of an industrial water solution (3), - of a water solution treated on a cationic ion exchanger (5), - a demineralized water solution (7), - of an aqueous solution containing Mg ions 2+ and that 2+(9), said mixing unit (31) being further configured to mix a first volume (VI) of said first aqueous solution and a second volume (V2) of said second aqueous solution, so as to produce a mixing volume (Vml) of a mixing solution characterized by a mixing composition (cml) and constituting all or part of the cooling water (1), said first volume (VI) of the first aqueous solution and second volume (V2) of the second aqueous solution being determined as a function of said first composition (cl) and said second composition (c2), and such that the mixing composition (cml) tends towards a predetermined final target composition (cfc). Casting device (100) according to claim 13, further comprising a reverse osmosis unit (27) or a demineralizing resin ion exchanger (25), said reverse osmosis unit inverse (27) or said ion exchanger on demineralizing resin (25) comprising means for connecting it to the mixing unit (31) and to the cation exchanger (20). Casting device (100) according to claim 13 or 14, wherein the mixing unit (31) comprises a temperature control system (61) including a temperature sensor (63) configured to measure a mixing temperature corresponding to the temperature of the mixing solution, said temperature control system (61) being configured to maintain the mixing temperature between 10°C and 35°C, preferably between 12°C and 30°C.

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