• 专利附录
  • 专利说明
  • 权利要求
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    • 专利摘要:
    Process for producing a phosphocalcic reagent according to which: in a first step, a source of calcium and a source of phosphate ions in water are used in a molar ratio adjusted so as to obtain a Ca / Ca ratio; P between 0.5 and 1.6, and the calcium source is reacted with the phosphate ions at a pH of between 2 and 8, to obtain a suspension (A) of calcium phosphate, and - in a second step is added to the suspension (A) an alkaline compound comprising hydroxide ions to adjust a pH greater than 8.5, and a complement of calcium source to obtain a suspension (B) of phosphocalcic reagent having a molar ratio Ca / P greater than 1.6.
    公开号:FR3021045A1
    申请号:FR1454383
    申请日:2014-05-16
    公开日:2015-11-20
    发明作者:Patrick Perrin；Olivier Jacques F J G Bodson；Thierry Delplanche；Dirk Breugelmans
    申请人:Solvay SA；
    IPC主号:
    专利说明:

    [0001] The invention relates to a method for producing a phosphocalcic reagent and to a method for producing a phosphocalcic reagent. It also relates to the reagent obtained and its use for the treatment of liquid effluents or the treatment of substances contaminated with heavy metals.
    [0002] The problems posed by the impact of heavy metals in the environment are well known. Many industrial processes discharge effluents, liquid or gaseous, heavily loaded with heavy metals. The term "heavy metals" refers to metals with a specific gravity of at least 5 g / cm3, as well as beryllium, arsenic, selenium and antimony, in accordance with the generally accepted definition (Heavy Metals in Wastewater). and Sludge Treatment Processes, Vol I, CRC Press Inc, 1987, page 2). Lead or cadmium are particularly significant examples, given its harmful influence on the human body. Nickel is another example of its allergenic effect.
    [0003] It is thus useful to have reagents capable of absorbing and retaining large quantities of heavy metals to treat industrial liquid effluents or wastewater from treatment plants before their release into the natural environment, or even the treatment of natural aquifers, some of which are naturally charged with heavy metals.
    [0004] Another example of a problem related to heavy metals is the combustion of waste, especially household waste, producing a vaporization of heavy metals, these vapors being entrained in the combustion fumes. To avoid contamination of the environment, it is necessary to have smoke treatment processes capable of performing an effective purification of heavy metals. The toxic substances removed from the smoke during its purification are found in a residue, which must often be treated itself before being able to be valorized for example or to be dumped. Indeed, if the purification residue which contains the heavy metals removed from the smoke is subjected for example to the action of rainfall having acidity when it is in a landfill, it is frequent that it releases into the environment a part of the heavy metals it contains. This can then cause a pollution of the subsoil. It is therefore essential that the heavy metals are immobilized in the purification residue. FR2912396 describes a method for producing a phosphocalcic reagent in which a source of calcium carbonate and a source of phosphate ions are reacted in water in a ratio by weight adjusted to obtain a ratio molar Ca / P between 1.4 and 1.8, at a pH between 5 and 10, preferably between 7 and 8, with stirring controlled to cause the appearance of a calcium phosphate gel having a viscosity of at least 200 centipoise (mPa $). The phosphocalcic reagent obtained by such a process is in the form of particles having a high BET surface area of the order of 130 m 2 / g. However, the particles of such a reagent have the disadvantage of being particularly fine, with average diameters by weight of less than 10 pin, which poses problems of use in the treatment of liquid effluents by mud veil because these particles are easily removed from reactors at low effluent flow speeds, which can lead to loss of reagents. On the other hand, such particles release significant quantities of phosphates during their implementation, which is generally avoided to limit the risk of eutrophication of streams, phosphorus being a natural fertilizer promoting the growth of algae. The aim of the invention is to provide an improved process for the production of phosphocalcic reagent, which makes it possible to obtain an effective reagent for immobilizing heavy metals, in particular in effluent treatment plants by means of a mud web, and limiting the emissions of phosphates. both during the production of the reagent and when using the reagent to fix heavy metals. Accordingly, the invention relates to a method for producing a phosphocalcic reagent according to which: in a first step, a source of calcium and a source of phosphate ions are used in water in a set molar ratio so as to obtain a Ca / P ratio of between 0.5 and 1.6, and the calcium source is reacted with the phosphate ions at a pH of between 2 and 8, in order to obtain a suspension (A) of calcium phosphate, and - in a second step is added to the suspension (A) an alkaline compound comprising hydroxide ions to adjust a pH greater than 8.5, preferably at least 9, or preferably at least 10, and a complement of calcium source in order to obtain a suspension (B) of phosphocalcic reagent having a Ca / P molar ratio greater than 1.6, preferably greater than 1.65. It has been found that the reagent obtained by the process according to the invention has original properties. It consists of particles whose average diameter D50 is greater than 10 μm, generally greater than 20 μm, or even greater than 50 μm. This average diameter of the reagent is, however, in general, however, preferably less than 200 μm, or even less than 150 μm. This makes it possible to limit the stirring powers to prevent the reagent particles from settling too easily in a stirred reactor or requiring high speeds of the fumes to be treated at the injection points of the reagent for treating the fumes. These particles are composed of calcium phosphate whose structure is intermediate between tricalcium phosphate and phosphocalcic hydroxyapatite. These particles then evolve very rapidly towards an apatitic structure.
    [0005] It has also been found that the reagent according to the present invention has a remarkably low solubility of the phosphates contained in the reagent particles. The inventors without wishing to be bound by a theoretical explanation believe that this behavior is due to the fact that during the second step the addition of an alkaline compound comprising hydroxide ions to adjust a pH of at least 8.5, or even at least 9 or at least 10 makes it possible to form, on the surface of the particles of the phosphocalcic reagent, mixed calcium hydroxide and calcium phosphate compounds, effectively limiting the solubility of phosphates, for example during the treatment of waste waters having a close pH. neutrality.
    [0006] The particles of phosphocalcic reagent according to the invention generally comprise at least 50% of calcium phosphate, advantageously at least 60% and more advantageously still at least 80% of calcium phosphate. The remainder at 100% generally comprises: water, of the order of 0 to 20%, advantageously 5 to 20%, calcium carbonate of the order of 0 to 20%, advantageously 5 to 20%. %, calcium hydroxide from 0 to 20%, preferably from 1 to 4%. The phosphocalcic reagent particles may further contain residual compounds from the use of raw materials in the process such as: CaCl 2, Ca (NO 3) 2, sands or clays; these constituents are in general less than 5% by weight, advantageously less than 2% by weight.
    [0007] The term apatite refers to a family of inorganic compounds whose chemical formula can be written in the following general form: Meio (X04) 6Y2 In this formula, Me generally represents a divalent cation (Me2 +, XO4 a trivalent anionic group (X043-) and Y is a monovalent (Y-) anion.Calo (PO4) 6 (OH) 2 phosphocalcic hydroxyapatite crystallizes in the space group of the hexagonal system.This structure consists of a compact hexagonal stack of X04 groups, forming two types of parallel tunnels.
    [0008] The existence of these tunnels gives apatites chemical properties similar to those of zeolites. Gaps can also be caused either by the departure of anions and cations, or by the presence of cations or anions of different valence. Apatites therefore appear as particularly stable buildings that can tolerate large differences in composition.
    [0009] Hydroxyapatite should not be confused with tricalcium phosphate (TCP), which has a similar weight composition: Ca3 (PO4) 2. The Ca / P molar ratio of TCP is 1.5 while it is 1.667 for hydroxyapatite. Industrial apatites marketed as food additives or mineral fillers are, as a rule, variable mixtures of TCP and hydroxyapatite. Other calcium and phosphate salts, including TCP, do not have the same properties as hydroxyapatite. Although TCP can also react with heavy metals, hydroxyapatite is more interesting because it can enclose metals in the form of an insoluble matrix and therefore quite inert.
    [0010] In the present invention, the source of calcium advantageously comprises calcium carbonate, or calcium oxide, or calcium hydroxide, or calcium chloride, or calcium nitrate, or acetate of calcium. calcium. The source of calcium is more preferably a limestone, or a mixture of limestone and oxide or calcium hydroxide. More preferably, the source of calcium is in the form of a powder or an aqueous suspension of powder and the powder is chosen from: calcium carbonate, calcium oxide, calcium hydroxide, or their mixture, and the powder has average particle size less than 3001..tm. It is advantageous for the calcium source chosen from calcium carbonate, calcium oxide, calcium hydroxide or their mixtures to be in the form of a powder or of an aqueous suspension of powder, to have a fine particle size. In a recommended variant, the average particle diameter of the powder is less than 300 l..tm, advantageously to 2001..tm, preferably less than 1001..tm. The average diameter considered is the D50, that is to say the diameter such that 50% by weight of the particles have a diameter less than the said value.
    [0011] In the present invention, various sources of phosphate ions may be used, in particular: phosphoric acid; or a dihydrogen phosphate salt such as a sodium, potassium or ammonium dihydrogen phosphate salt, preferably a dihydrogen phosphate salt; sodium salt; or a monohydrogenphosphate salt such as a sodium, potassium or ammonium monohydrogenphosphate salt, preferably a sodium monohydrogenphosphate salt. In the present invention, phosphoric acid is preferred because it is more available and of lower cost than the dihydrogen and monohydrogen phosphate salts. In the process according to the invention, in the first step the molar ratio Ca / P is in particular: between 0.50 and 1.35, preferably between 0.70 and 1.30, or between 1.4 and 1.6, preferably between 1.4 and 1.5. In the first step, where calcium and phosphate are used at a Ca / P molar ratio of between 0.5 and 1.6 and in which they are reacted at a pH of between 2 and 8, the compounds formed in the suspension (A) are a mixture of monocalcium phosphate (MCP) having the weight formula Ca (H2PO4) 2, dicalcium phosphate (DCP) having the weight formula CaHPO4, or its hydrate brushite having the weight formula CaHPO4.2H20, and octacalcium having weight formula Ca8H2 (PO4) 6.6.5H2O. The molar ratios Ca / P are respectively for these compounds of: 0.5 (MCP), 1.0 (DCP and brushite), 1.33 (Octacalcium).
    [0012] To promote the formation of MCP and DCP in the first step, a Ca / P ratio of between 0.50 and 1.35, preferably between 0.7 and 1.30, is preferred. This Ca / P ratio is particularly advantageous when the calcium source of the first stage comprises calcium carbonate, and the source of phosphate is phosphoric acid (H 3 PO 4) or is a dihydrygenophosphate salt such as a sodium salt or potassium or ammonium. This makes it possible to obtain a rapid attack of calcium carbonate and rapid degassing of CO2. In addition to calcium carbonate, the calcium source may comprise calcium oxide, or calcium hydroxide, or calcium chloride, or calcium nitrate, or calcium acetate. To promote the formation of DCP and Octacalcium in the first step, a Ca / P ratio of 1.4 to 1.6, preferably 1.4 to 1.5, is preferred. This molar ratio is advantageous when using a source of calcium having less than 30% by weight of carbonate, such as: calcium oxide, or calcium hydroxide, or calcium chloride, or calcium nitrate, or calcium acetate.
    [0013] In the present invention, in the first step, the source of calcium and the phosphate ions are generally reacted at least 0.1 hour, preferably at least 0.5 hours. It is not useful to have them react for too long periods. Advantageously, the source of calcium and the phosphate ions are reacted at most 4 hours, more advantageously at most 2 hours, or even at most 1 hour. For example, a time of one hour at pH 5 already allows a good reaction of calcium and phosphate ions, and allows sufficient release of CO2 when using a calcium source comprising calcium carbonate, before moving to the second step. In the present invention, in the second step, the suspension (B) of phosphocalcic reagent generally has a Ca / P molar ratio of at most 5, preferably at most 3, even more preferred at most 2. In the present invention, it is advantageous that in the second step, the alkali compound used comprising hydroxide ions is sodium hydroxide and / or calcium hydroxide.
    [0014] In the process according to the invention it is particularly advantageous if the calcium source supplement is chosen from calcium chloride, calcium nitrate or calcium acetate, preferably calcium chloride, and whether it is added in addition to the alkaline compound, in order to finely adjust the Ca / P ratio and in order to limit the concentration of phosphorus element in the aqueous solution (C) of the suspension (B) to at most 5 mmol, advantageously at most 0.5 mmol more preferably at most 0.05 mmol of phosphorus element per liter of aqueous solution (C). This makes it possible, in fact, coupled with the use of hydroxide ions for adjusting the pH of the second stage, to limit phosphate losses in the production water.
    [0015] In the present invention, in general, the agitation and the suspension density in the second stage and advantageously also in the first stage are adjusted to prevent the appearance of a calcium phosphate gel having a viscosity of at least 200 cps. Indeed, the production of a gel, even in the presence of the second step, has the consequence of producing particles of phosphocalcic reagent of fine particle size, with weight average D50 of less than 10 μm, which is a disadvantage for certain applications. liquid effluents such as those using a sludge blanket. The solids suspension density of the suspension (A) at the first stage is generally at most 20%. The solids suspension density of the suspension (b) at the second stage is generally at most 15%.
    [0016] In a first embodiment of the present invention, the first step is performed at a temperature below 50 ° C, preferably at most 45 ° C, or at most 40 ° C. This makes it possible to obtain a phosphocalcic reagent at the end of the second step in the form of particles of large to medium particle size and having a high specific surface area. The invention relates in particular to a phosphocalcic reagent particle by this first embodiment, comprising at least 60% by weight of hydroxyapatite, and having an average size of at least 30 μm, preferably at least 50 μm, and having a surface area of at least 50 m 2 / g, preferably at least 100 m 2 / g, and comprising at least 2%, preferably at least 5%, and more preferably at least 6% by weight of ions hydroxides. In a second embodiment of the present invention, the first step is carried out at a temperature of at least 50 ° C, preferably at least 55 ° C, or at least 60 ° C. This makes it possible to obtain a phosphocalcic reagent at the second stage in the form of particles of fine particle size and having a smaller specific surface area. The invention particularly relates to a phosphocalcic reagent particle obtained by the method according to this second embodiment, comprising at least 60% by weight of hydroxyapatite, and having an average size of at most 30 μm, preferably at most 20 μm, and having a specific surface area of at least 15 m 2 / g, preferably at least 50 m 2 / g, and having a hydroxide ion content of greater than 2% by weight, preferably greater than 3.5% and more preferably greater than 4% by weight. In the first or second embodiment of the process of the present invention, it is advantageous for the second step to be carried out at a temperature of at least 45 ° C., preferably at least 55 ° C., or at least 55 ° C. 60 ° C, or at least 80 ° C. This makes it possible in fact to rapidly convert the phosphocalcic compounds of the first step phosphocalcic reagent according to the invention, with a good fixation of hydroxide ions in the core and surface of the phosphocalcic reagent, and to exhaust more quickly the phosphate solution of the suspension (B). Advantageously, the second step is carried out at a temperature of at least 45 ° C., preferably at least 55 ° C., or at least 60 ° C., or at least 80 ° C., for a period of at least less 0.1 to 0.5 hours. In general, the addition of the alkaline compound comprising hydroxide ions to adjust the pH of the second step, and the calcium source complement to obtain a suspension (B) of phosphocalcic reagent having a Ca / P molar ratio greater than 1.6 does not last more than 4 hours, preferably not more than 2 hours. Advantageously, once the additions of the hydroxide ions to adjust the pH of the second step, and the addition of the complement of calcium source, completed, the suspension (B) is allowed to cool from 1 to 24 hours, preferably at least 10 hours to room temperature. This makes it possible to mature the phosphocalcic reagent and to reduce the residues of MCP / DCP or Brushite, or of Octacalcium (precipitated during the first step), with Hydroxyapatite and with calcium phosphate and calcium hydroxide complexes, within the suspension (B ). Optionally, in the process of the present invention, at the end of the second step, the suspension (B) comprises an aqueous solution (C) and phosphocalcic reagent particles, and: in a third step, a portion of the aqueous solution (C) is separated from the suspension (B) to obtain an aqueous suspension (D) comprising at least 18% and at most 50% phosphocalcic reagent particles, or to obtain a moist solid (D ') comprising at least 50% and not more than 80% phosphocalcic reagent particles, or a powdery solid (D ") comprising not less than 80% and not more than 95% phosphocalcic reagent particles and not less than 5% and not more than 20% Therefore, the present invention also relates to an aqueous suspension (D) comprising at least 25% and at most 50% phosphocalcic reagent particles obtained by the present method.The phosphocalcic reagent obtained according to the present invention is effective for the treatment of substance s contaminated with metal and / or non-metallic elements, in particular contaminated with heavy metals. Therefore, the present invention also relates to a method of purifying a substance contaminated with metallic and / or non-metallic elements according to which the substance, such as water, gases, fumes, solid residues or soils, is placed in contact with the phosphocalcic reagent obtained according to the process of the present invention, in particular with the phosphocalcic reagent of the present invention, or with the suspension (D) or the wet solid (D ') or the solid powder (D ") of the present invention, so that at least a part of the metal elements of the substance is adsorbed by the phosphocalcic reagent In the purification method according to the invention, the contaminated substance may be a smoke containing metal elements and / or not such as As, B, F, Se, and according to which the phosphocalcic reagent, or the aqueous suspension (D '), or the wet solid (D'), or the powdery solid (D "), is dispersed d fumes, the fumes being at a temperature above 100 ° C, the resulting mixture is then separated to obtain a resulting solid and partially purified smoke metal and / or non-metallic elements. In the purification method according to the invention, the contaminated substance may be a liquid effluent containing metal elements such as: Al, Ag Ba, Be, Ce, Co, Cd, Cu, Cr, Fe, Hg, La, Li, Mo, Ni, Pb, Pd, Rb, Sb, Sn, Th, Ti, U, V, Y, Zn and / or non-metallic such as As, B, F, Se, according to which the reagent is mixed in the liquid effluent. phosphocalcic or phosphocalcic reagent suspension for a time sufficient for the phosphocalcic reagent to absorb at least a portion of the metallic and / or non-metallic elements and the mixture is subjected to clarification to produce a partially purified liquid in metallic element and / or not metal, on the one hand, and the phosphocalcic reagent charged in metallic and / or non-metallic element that is discarded. Preferably, the phosphocalcic reagent is used with the liquid effluent in a contact reactor, such as a slurry vane reactor or a fluidized bed. The contact time between the phosphocalcic reagent and the liquid effluent is generally at least 15 minutes, advantageously at least 30 minutes, more preferably at least one hour. In a particularly advantageous embodiment of the invention, the liquid effluent is introduced into a slurry veil contact reactor in which the phosphocalcic reagent is present in a mass concentration of at least 0.5% by weight and in general at most 10% by weight. % in weight ; a liquid is collected overflow from the mud-veil reactor; a flocculant is added to the collected liquid to form a mixture comprising phosphocalcic reagent particles entrained out of the contact reactor and flocculated; said mixture is then introduced into a decanter where the mixture is separated into: - the partially purified liquid in metallic element and / or in non-metallic element, and said liquid is collected in overflow of the clarifier, - and in an underflow of the decanter comprising flocculated and decanted phosphocalcic reagent particles collected underwater from the decanter; and at least a portion of the decanter underflow containing flocculated and decanted phosphocalcic reactant particles is recycled to the slime veil contact reactor. The effectiveness of the treatment in metallic elements and / or in non-metallic elements can be controlled by comparing the concentrations of the elements upstream (on the liquid effluent) and downstream of the treatment (on the partially treated liquid), for example by a automatic analyzer or by sampling and analysis. The charge of phosphocalcic reactant of the contact reactor is generally regularly renewed in part. For example by partially purging the phosphocalcic reagent loaded with metallic and / or non-metallic element at the underflow of the settler, and adding fresh phosphocalcic reagent into the contact reactor. Such a process thus ensures a "chemical polishing" of the liquid effluents. The method is particularly advantageous in the case where the partly purified liquid in metallic element and / or non-metallic element, is then treated in a biological treatment station producing purification sludge. This makes it possible to reduce the concentrations of such elements of said sewage sludge and to valorize them, for example in agriculture or in regional development. In the purification method according to the invention, the contaminated substance may be a solid residue or a soil contaminated with metal elements such as Al, Ag Ba, Be, Ce, Co, Cd, Cu, Cr, Fe, Hg, La, Li, Mo, Ni, Pb, Pd, Rb, Sn, Th, Ti, U, V, Y, Zn and / or non-metallic such as As, B, F, Se, according to which one injects into the solid residue or the soil in the vicinity of the metallic or non-metallic elements the phosphocalcic reagent, or the aqueous suspension (D), or the wet solid (D '), or the powdery solid (D ") of phosphocalcic reagent for a time sufficient for the reagent phosphocalcic acid adsorbs at least a portion of the metallic and / or non-metallic elements The following examples serve to illustrate the invention: In these examples, the particle size measurement is carried out on a Beckman Coulter LS 230 type diffraction laser particle size analyzer ( wavelength laser 750 nm) on particles suspended in water and using a size distribution calculation based on the Fraunhofer diffraction theory (particles greater than 10 μm) and on the Mie diffusion theory (particles smaller than 10 μm), the particles being considered spherical.
    [0017] The BET surface area was determined by gas adsorption on ASAP2020 from Micromeritics. Prior to analysis, the samples (0.7 to 1 g) were pretreated under vacuum at 250 ° C until a stable vacuum of 4-5'Aar was reached. Measurements were made using nitrogen as an adsorbent gas at 77 ° K by volumetric method, according to ISO 9277: 2010 standard (Determination of specific surface area of solids by gas adsorption - BET method). The BET surface area was calculated in a relative pressure range (P / PO) ranging from about 0.05 to 0.20. In the examples, the heavy metal contents of the solid state substances were measured as follows. A sample of the analyte (approximately 200 mg) was supplemented with 1 ml of 65% suprapuric nitric acid and 3 ml of 37% supernatant hydrochloric acid and then subjected to microwave radiation in a sealed container. closed, in order to mineralize it (destruction of the (hydro) carbon matrix to obtain a mineral residue containing the analytes). This solution, supplemented with an internal standard (Scandium), is brought to volume (50 ml) with ultrapure water. The solution to be analyzed is then filtered if necessary (0.45 μm) and injected as an aerosol into an argon plasma maintained by inductive coupling. At temperatures of 6000 to 8000 ° K, the atoms and ions formed from the sample are excited and return to the ground state by emitting radiation characteristic of the element in the UV-visible range (130 nm to 800 nm) (ICP OES). The various radiations are separated by diffraction on a network with a large number of lines and the intensity of the selected lines is measured. The concentration of the desired elements in the measurement solution is obtained after calibration of the apparatus with solutions of known concentrations of each of the desired elements. The concentration of these elements in the starting sample is then calculated taking into account the dilution performed during the various preparation steps. Example 1 (in accordance with the invention) 500g of limestone in the form of a D 50 powder of less than 300 μm are dispersed in 2469 ml of water at a temperature of 20 ° C. 646 g of phosphoric acid (H 3 PO 4) at a mass concentration of 75% are added to this suspension over a period of 20 minutes using a peristaltic pump. This addition is accompanied by a temperature increase of 13 ° C. The mixture is maintained vigorously stirring by means of a stirrer with 4 blades inclined at 700 rpm (power dissipated by the stirrer of the order of 1 kW / m 3), ensuring a good mixture of sources of calcium and water. phosphate ions, and to degas the carbon dioxide formed during the addition of acid. At the end of the addition of acid, the suspension is then heated to 60 ° C. Once the suspension at this temperature, a 25% weight suspension of Ca (OH) 2 (244 g of Ca (OH) 2 suspended in 732 g of water) is added using a peristaltic pump in order to maintain the pH of the suspension at 10 +/- 0.5 for 60 minutes. After 60 minutes, the heating is stopped and stirring is maintained but reduced to 50% in rotation speed and the suspension is allowed to cool for about ten hours until it returns to room temperature (22 ° C.). The phosphocalcic reagent particles of the suspension have the composition: 94% by weight of hydroxyapatite, 5% by weight of calcium carbonate, and comprising 3.5% hydroxide ion. The physical characteristics of the particles of phosphocalcic reagent obtained are given in Example 3. Example Ibis (in accordance with the invention): 500g of limestone are dispersed in 2469m1 of water at 50 ° C. On this suspension is then added 646g of H3PO4 (75%) in 20 minutes using a peristaltic pump. The mixture is maintained vigorously stirring (1kW / m3) by means of a stirrer with 4 blades, allowing the mixing of the compounds and degassing the carbon dioxide formed during this step. At the end of the addition of acid, the mixture is stirred for 30 minutes. A suspension of Ca (OH) 2 at 25% by weight (ie 250 g of Ca (OH) 2 suspended in 750 g of water) is then added using a peristaltic pump so as to maintain the pH at 10. +/- 0.5 for 60 minutes. Once the 60 minutes passed, the heating is stopped but stirring is maintained but reduced to 50% of its power and the suspension is allowed to cool for about ten hours until it returns to room temperature (22 ° C.). The phosphocalcic reagent particles of the suspension have the composition: 95% by weight of hydroxyapatite, 4% by weight of calcium carbonate, and comprising 3.6% hydroxide ion. The physical characteristics of the phosphocalcic reagent particles obtained are given in Example 3.
    [0018] Example 2 (in accordance with the invention): 100 g of limestone are dispersed in 148 ml of water at ambient temperature of 20 ° C. This suspension is then poured into a solution of 71 g of NaH 2 PO 4 in 166 ml of water at ambient temperature of 20 ° C. The mixture is maintained vigorously stirring, allowing the mixing of the compounds and the degassing of the carbon dioxide formed during this step, for 30 minutes. Once the addition is complete, a solution of 43 g of CaCl2.2H2O in 44 g of water is poured in 5 minutes in order to convert the soluble phosphates which have not yet reacted. Afterwards, 58 g of a slurry of lime at 25% by weight are added with vigorous stirring by means of a stirrer with 4 inclined blades.
    [0019] Once all the lime slurry has been introduced, the stirring speed is reduced to 50% and the suspension is stirred for 10 hours. Example 3 (Compliant) The suspension obtained in Example 1 consists of phosphocalcic reagent particles having a D50 of 61 μm and a specific surface area of 110 m 2 / g suspended in an aqueous solution. The suspension is then centrifuged to obtain a moist solid containing 55% ± 5% of dry matter. Example 4 (in conformity) The wet solid obtained in Example 3 is then dried in a ventilated enclosure at a temperature of 40 ° C. ± 5 ° C. until a solid at 94% of dry matter is obtained, formed as a particle powder. having a particle size D50 of 61 μm, a specific surface area of 110 m 2 / g. Example 5 (compliant) The suspension obtained in the example ibis centrifuged to lead to obtaining a wet solid 55% ± 5% dry matter; the solid is formed of particles having a D50 of 10 μm and a specific surface area of 16 m² / g. Example 6 (in conformity) The suspension obtained in Example 1 is used in a 20-liter reactor with a transparent wall. The reactor is equipped with an agitator with 4 inclined blades rotating at about 75 rpm, and whose speed of rotation is adjusted in order to keep the solid in suspension and form in the reactor a slime web visible to the naked eye , occupying 80 +/- 5% of the reactor volume, in the lower part of the reactor. The reactor is fed continuously with liquid effluent at a rate of 25 L / h at the base of the slurry vane reactor. The overflow of the reactor is added with a flocculant of polyacrylamide type Ref. Floerger AN905SH, regulated in flow rate of the order of 200 mL / h to obtain 1 ppm of flocculant with respect to the water leaving the sludge reactor. The overflow of the reactor and the flocculant feed the base of a decanter with a surface of 0.0154 m2 making it possible to obtain a rising speed of the treated water of 1.3 m / h. The treated water is collected over the decanter, and sludge decanted at the bottom of the decanter is reintroduced semi-continuous in the slurry vane reactor with a pump operating at a rate of 6 L / h. EXAMPLE 7 (COMPATIBLE) The solid obtained in Example 4 is used in a fluidized bed consisting of a column, 6 cm in diameter, and a volume of 2 liters. The fluidized bed is fed at its base by the aqueous effluent to be treated and by a liquid shuttle (cf infra). The phosphocalcic reagent containing apatite is kept in suspension in the fluidized bed by means of a liquid shuttle of 29 L / h produced by a recirculation pump operating on a 3 L buffer tank fed by the overflow of the fluidized bed. . The system ensures a contact time of at least 15 minutes between the phosphocalcic reagent and the effluent to be treated. Flocculant, SNF Floerger AN905VHM type, is injected at a flow rate of 120 mL / h into the shuttle of 29 L / h before entering the fluidized bed to ensure a concentration of about 1 ppm in the aqueous effluent to be treated.
    [0020] The treated aqueous effluent is extracted by overflow from the buffer reactor at the outlet of the fluidized bed.
    权利要求:
    Claims (13)
    [0001]
    REVENDICATIONS1. Process for producing a phosphocalcic reagent according to which: in a first step, a source of calcium and a source of phosphate ions in water are used in a molar ratio adjusted so as to obtain a Ca / Ca ratio; P between 0.5 and 1.6, and the calcium source is reacted with the phosphate ions at a pH of between 2 and 8, to obtain a suspension (A) of calcium phosphate, and - in a second step is added to the suspension (A) an alkaline compound comprising hydroxide ions to adjust a pH greater than 8.5, and a complement of calcium source to obtain a suspension (B) of phosphocalcic reagent having a molar ratio Ca / P greater than 1.6.
    [0002]
    2. Method according to the preceding claim, wherein the source of calcium comprises calcium carbonate, or calcium oxide, or calcium hydroxide, or calcium chloride, or calcium nitrate, or calcium acetate.
    [0003]
    3. A process according to any one of the preceding claims, wherein the source of phosphate ions is phosphoric acid.
    [0004]
    4. Method according to any one of the preceding claims, wherein in the first step the molar ratio Ca / P is: between 0.50 and 1.35, or between 1.4 and 1.6.
    [0005]
    5. Method according to any one of the preceding claims, wherein the stirring and the suspension density, in the second step and preferably also in the first step, are adjusted to prevent the appearance of a calcium phosphate gel. having a viscosity of at least 200 cps.
    [0006]
    6. A process according to any of the preceding claims wherein in the second step the alkali compound used comprising hydroxide ions is sodium hydroxide and / or calcium hydroxide.
    [0007]
    7. A method according to any one of the preceding claims, wherein in the second step, the calcium source supplement is selected from calcium chloride, calcium nitrate, or calcium acetate, preferably sodium chloride. calcium, and is added in addition to the alkaline compound, to finely adjust the Ca / P ratio and limit the concentration of phosphorus element in the aqueous solution (C) of the suspension (B) to at most 5 mmol, preferably at most 0.5 mmol, more preferably at most 0.05 mmol of phosphorus element per liter of aqueous solution (C).
    [0008]
    The process of any of the preceding claims wherein the first step is conducted at a temperature below 50 ° C.
    [0009]
    9. Process according to any one of claims 1 to 7 wherein the first step is carried out at a temperature of at least 50 ° C.
    [0010]
    The process of any preceding claim wherein the second step is conducted at a temperature of at least 45 ° C.
    [0011]
    11. Phosphocalcic reagent particle obtained by the process according to claim 8 comprising at least 60% by weight of hydroxyapatite, and having an average size of at least 30 μm, and having a specific surface area of at least 50 m 2 / g.
    [0012]
    12. Method for purifying a liquid effluent containing metallic elements such as: Al, Ag Ba, Be, Ce, Co, Cd, Cu, Cr, Fe, Hg, La, Li, Mo, Ni, Pb, Pd, Rb, Sb, Sn, Th, Ti, U, V, Y, Zn and / or non-metallic such As, B, F, Se, according to which the phosphocalcic reagent obtained by the process of the invention is mixed in the liquid effluent. any one of claims 1 to 10 for a period of time sufficient for the phosphocalcic reagent to absorb at least a portion of the metallic and / or non-metallic elements and the mixture is clarified to produce a partially purified liquid as a metallic element and / or not metal, on the one hand, and the phosphocalcic reagent charged in metallic and / or non-metallic element that is discarded.
    [0013]
    13. The purification method according to claim 12, wherein the phosphocalcic reagent is used with the liquid effluent in a slurry veil contact reactor; with a contact time between the phosphocalcic reagent and the liquid effluent of at least 15 minutes; and wherein said slime veil contact reactor, the phosphocalcic reagent is present at a mass concentration of at least 0.5% by weight; a liquid is collected overflow from the mud-veil reactor; a flocculant is added to the collected liquid to form a mixture comprising phosphocalcic reagent particles entrained out of the contact reactor and flocculated; said mixture is then introduced into a decanter where the mixture is separated into: - the partially purified liquid in metallic element and / or in non-metallic element, and said liquid is collected in overflow of the clarifier, - and in an underflow of the decanter comprising flocculated and decanted phosphocalcic reagent particles collected underwater from the decanter; and at least a portion of the decanter underflow containing flocculated and decanted phosphocalcic reactant particles is recycled to the slime veil contact reactor.
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    公开号 | 公开日
    KR20170008261A|2017-01-23|
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    CA2948573A1|2015-11-19|
    EA201692311A1|2017-04-28|
    CN106660794B|2019-02-12|
    EP3142784A1|2017-03-22|
    CL2016002909A1|2017-09-01|
    US20200330955A1|2020-10-22|
    MX2016015088A|2017-05-30|
    AU2015261392A1|2016-12-15|
    WO2015173437A1|2015-11-19|
    BR112016026394A8|2020-10-20|
    FR3021045B1|2020-02-21|
    US20170080401A1|2017-03-23|
    EP3142784B1|2021-12-29|
    CN106660794A|2017-05-10|
    AU2015261392B2|2019-02-28|
    BR112016026394A2|2017-08-15|
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    法律状态:
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    2015-11-20| PLSC| Publication of the preliminary search report|Effective date: 20151120 |
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    2020-04-14| PLFP| Fee payment|Year of fee payment: 7 |
    2021-04-12| PLFP| Fee payment|Year of fee payment: 8 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1454383|2014-05-16|
    FR1454383A|FR3021045B1|2014-05-16|2014-05-16|PROCESS FOR PRODUCING A PHOSPHOCALCIC REAGENT, REAGENT OBTAINED AND ITS USE|FR1454383A| FR3021045B1|2014-05-16|2014-05-16|PROCESS FOR PRODUCING A PHOSPHOCALCIC REAGENT, REAGENT OBTAINED AND ITS USE|
    US15/311,396| US10814303B2|2014-05-16|2015-05-18|Process for producing a calcium phosphate reactant, reactant obtained and use thereof in the purification of liquid effluents|
    CA2948573A| CA2948573A1|2014-05-16|2015-05-18|Process for producing a calcium phosphate reactant, reactant obtained and use thereof in the purification of liquid effluents|
    AU2015261392A| AU2015261392B2|2014-05-16|2015-05-18|Process for producing a calcium phosphate reactant, reactant obtained and use thereof in the purification of liquid effluents|
    PCT/EP2015/060923| WO2015173437A1|2014-05-16|2015-05-18|Process for producing a calcium phosphate reactant, reactant obtained and use thereof in the purification of liquid effluents|
    MX2016015088A| MX2016015088A|2014-05-16|2015-05-18|Process for producing a calcium phosphate reactant, reactant obtained and use thereof in the purification of liquid effluents.|
    KR1020167034714A| KR20170008261A|2014-05-16|2015-05-18|Process for producing a calcium phosphate reactant, reactant obtained and use thereof in the purification of liquid effluents|
    BR112016026394A| BR112016026394A8|2014-05-16|2015-05-18|process to produce a calcium phosphate reagent, a calcium phosphate reagent particle, and a method of purifying a liquid effluent|
    CN201580026606.5A| CN106660794B|2014-05-16|2015-05-18|For producing method, reactant obtained and its purposes in purification of liquid effluent of calcium phosphate reactant|
    EP15725547.2A| EP3142784B1|2014-05-16|2015-05-18|Process for producing a calcium phosphate reactant|
    EA201692311A| EA201692311A1|2014-05-16|2015-05-18|METHOD OF MANUFACTURE OF REAGENT - CALCIUM PHOSPHATE, OBTAINED REAGENT AND ITS USE TO CLEAN LIQUID DRAINS|
    CL2016002909A| CL2016002909A1|2014-05-16|2016-11-15|Process to produce a calcium phosphate type reagent, the reagent obtained and its use in the purification of liquid effluents.|
    US16/920,796| US20200330955A1|2014-05-16|2020-07-06|Process for producing a calcium phosphate reactant, reactant obtained and use thereof in the purification of liquid effluents|
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