Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09C—TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES ; PREPARATION OF CARBON BLACK  ; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS
  • C09C3/00—Treatment in general of inorganic materials, other than fibrous fillers, to enhance their pigmenting or filling properties
  • C09C3/04—Physical treatment, e.g. grinding, treatment with ultrasonic vibrations
  • C09C3/041—Grinding
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B25/00—Phosphorus; Compounds thereof
  • C01B25/01—Treating phosphate ores or other raw phosphate materials to obtain phosphorus or phosphorus compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F120/00—Homopolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
  • C08F120/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F120/04—Acids; Metal salts or ammonium salts thereof
  • C08F120/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F20/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
  • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
  • C08F20/04—Acids, Metal salts or ammonium salts thereof
  • C08F20/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K23/00—Use of substances as emulsifying, wetting, dispersing, or foam-producing agents
  • C09K23/52—Natural or synthetic resins or their salts
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
  • C01P2004/00—Particle morphology
  • C01P2004/60—Particles characterised by their size
  • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer

Definitions

• the invention relates to a method for grinding phosphate rock in the presence of a particular anionic polymer with a molecular weight of between 1000 and 90,000 g / mol and which makes it possible to control the extent (S) of the volume distribution of the size of the rock. particles of mineral particles of phosphate obtained.
• the invention also provides a method of improving the production efficiency of a phosphate rock crushing method.
• Phosphate or phosphate rock allows in particular the preparation of phosphoric acid. After mining, the phosphate rock is crushed, then crushed and treated in an acidic environment to produce phosphoric acid.
• the grinding of phosphate rock generally results in particles whose size distribution varies greatly.
• the crushed phosphate rock particles generally transported or used in phosphoric acid preparation plants should generally have a size (do , 5) of less than 500 ⁇ m, preferably less than 300 ⁇ m or less than 200 ⁇ m. These particles should generally have a size (do , 5) greater than 10 ⁇ m, preferably greater than 40 ⁇ m or greater than 50 ⁇ m.
• the acid treatment requires controlling this distribution of particle sizes. Indeed, the particles whose size is too large must generally be ground again while the particles whose size is too small must be separated. Particles whose size is too small are then lost.
• the extent of the particle size distribution is evaluated from three characteristics of the size of the ground particles (do , 9 , do , i , do , 5 ) obtained by implementing the grinding method according to the invention.
• the characteristic do, 5 or median diameter is the value of the diameter of the particles of a population of particles for which 50% by volume of the particles have a size less than this value. In this case, 50% by volume of the particles have a size greater than this value.
• 50% of the total volume of the population of particles corresponds to the volume of particles with diameters less than do , 5.
• the median size therefore corresponds to the diameter which divides the distribution into two parts of equal areas.
• the characteristic do, 9 is the value of the particle diameter of a population of particles for which 90% by volume of the particles have a size less than this value. In this case, 10% by volume of the particles have a size greater than this value.
• the characteristic do , i is the value of the diameter of the particles of a population of particles for which 90% by volume of the particles have a size greater than this value.
• the volume size of the particles is measured by laser diffraction and the extent of the volume distribution of particle sizes is calculated according to the formula [(do , 9 - do , i ) / do , 5 ]. This extent of the particle size distribution is also known as span.
• Document WO 2019092381 describes a method for preparing an aqueous suspension of phosphate rock which is carried out in the absence of grinding.
• Document US 5183211 describes a method aimed at reducing the viscosity of a phosphate rock suspension during ore grinding.
• Document EP 1160197 also describes a method for grinding phosphate rock which uses a crosslinked polymer.
• the method according to the invention makes it possible to provide a solution to all or part of the problems of the phosphate rock crushing methods of the state of the art.
• the invention provides a method of preparing an aqueous suspension of mineral phosphate particles whose extent (S) of the volume distribution of particle sizes [(do , 9 - do , i ) / do , 5 ] measured by laser diffraction is less than 4.1, comprising the grinding of at least one phosphate material in the presence of water and at least one anionic polymer (P) with a molecular mass by weight (Mw) of between 1000 and 90,000 g / mol and obtained by polymerization reaction of at least one acid chosen from acrylic acid, methacrylic acid and their salts.
• the range (S) is less than 4.0 or less than 3.9. More preferably according to the invention, the extent (S) is less than 3.5 or less than 3. Much more preferably according to the invention, the extent (S) is less than 2.5 or less than 2.
• the grinding of the phosphate rock is followed by a step of separating the smallest particles.
• the method according to the invention also comprises at least one step of separating the fraction of particles of phosphate material whose size do , i is less than 4 ⁇ m or less than 5 ⁇ m.
• this step allows the separation of the fraction of particles of phosphate material whose size do , i is less than 10 ⁇ m or less than 20 ⁇ m.
• this step allows the separation of the fraction of particles of phosphate material whose size do , i is less than 40 ⁇ m or less than 50 ⁇ m.
• the separation is carried out by means of a device chosen from hydrocyclone, centrifuge and their combinations.
• the concentration by weight of particles of phosphate material in the aqueous suspension during grinding is greater than 10% or greater than 15%.
• the concentration by weight of particles of phosphate material in the aqueous suspension during grinding is greater than 25%. More preferably according to the invention, the concentration by weight of particles of phosphate material in the aqueous suspension during grinding is greater than 40% or greater than 50%.
• the phosphate material particles have a size C, 9 before crushing which is greater than 800 pm or greater than 1 000 pm or greater than 2500 microns.
• the material particles have a size C, 5 after grinding is less than 300 pm, preferably less than 250 microns or less than 200 pm.
• the preparation method according to the invention makes it possible to control the grinding time.
• the grinding time can vary, in particular from 0.5 to 10 hours or vary from 0.5 to 3 hours or from 0.5 to 4 hours or even from 0.5 to 5 hours.
• the grinding time is less than 5 hours and 30 minutes.
• the grinding time is less than 4 h and 30 min or less than 3 h. Much more preferably according to the invention, the grinding time is less than 2 hours and 30 minutes.
• the grinding time is less than 5 h and 30 min or even less than 4 h and 30 min for a concentration by weight of particles of phosphate material in the aqueous suspension during grinding greater than 25. % or greater than 40%. Also preferably according to the invention, the grinding time is less than 3 h or less than 2 h and 30 min for a concentration by weight of particles of phosphate material in the aqueous suspension during grinding greater than 10% or greater than 15%. Also very advantageously according to the invention, the grinding time can be reduced very significantly compared to the grinding methods of the state of the art.
• the method according to the invention makes it possible to reduce the grinding time necessary to obtain an aqueous suspension of mineral phosphate particles, the extent (S) of the volume distribution of particle sizes [(do, 9 - do , i ) / do , 5] measured by laser diffraction is less than 4.1.
• the grinding time is reduced by at least 10% compared to the grinding time carried out in the absence of polymer (P). More preferably according to the invention, the grinding time is reduced by at least 20% or at least 25% compared to the grinding time carried out in the absence of polymer (P).
• the grinding time is reduced by at least 30% or at least 40% compared to the grinding time carried out in the absence of polymer (P).
• the polymer (P) according to the invention is known as such.
• the polymer (P) used according to the invention is an anionic polymer with a molecular mass by weight (Mw) of between 1,000 and 90,000 g / mol and obtained by polymerization reaction of at least one acid chosen from acrylic acid, methacrylic acid and their salts.
• the polymer (P) is non-sulfonated. Also preferably, the polymer (P) is partially or totally neutralized. More preferably, it is partially or totally neutralized by means of a derivative comprising at least one element chosen from lithium, sodium, calcium, magnesium and their mixtures, much more preferably chosen from sodium, calcium and their combinations.
• the polymer (P) is known as such. It can be prepared by methods which are also known. Preferably, the polymer (P) is obtained by a polymerization reaction also implementing at least one other acid chosen from acrylic acid, methacrylic acid, maleic acid, itaconic acid and their salts or at least one ester of an acid. selected from acrylic acid and methacrylic acid.
• the preferred polymer (P) according to the invention is chosen from an acrylic acid homopolymer, a copolymer of acrylic acid and maleic acid.
• the polymer (P) according to the invention is completely neutralized, in particular by means of sodium or a combination of sodium and calcium, for example an equimolar combination of sodium and calcium.
• the anionic polymer (P) has a molecular mass by weight (Mw) of between 1000 and 90,000 g / mol measured by CES (size exclusion chromatography).
• the polymer (P) has a molecular mass by weight (Mw) of between 2000 and 90,000 g / mol, preferably between 2000 and 50,000 g / mol, more preferably between 2000 and 10,000 g / mol, and of more preferably between 2000 and 8000 g / mol.
• the molecular mass and the polymolecularity index of the polymers are determined by Steric Exclusion Chromatography (CES) or in English “Gel Permeation Chromatography” (GPC).
• CES Steric Exclusion Chromatography
• GPC Gel Permeation Chromatography
• This technique uses a Waters brand liquid chromatography apparatus equipped with a detector. This detector is a Waters brand refractometric concentration detector. This liquid chromatography apparatus is fitted with a steric exclusion column in order to separate the different molecular weights of the polymers studied.
• the liquid elution phase is an aqueous phase adjusted to pH 9.00 by means of 1 N sodium hydroxide containing 0.05 M of NaHCO 3 , 0.1 M of NaNCL, 0.02 M of triethanolamine and 0.03% of NaN3.
• the polymer solution is diluted to 0.9% dryness in the solvent for solubilizing the CES, which corresponds to the liquid phase for eluting the CES to which 0.04% of dimethylformamide is added, which plays a role. the role of flow marker or internal standard. Then, it is filtered at 0.2 ⁇ m. 100 ⁇ L are then injected into the chromatography apparatus (eluent: an aqueous phase adjusted to pH 9.00 with IN sodium hydroxide containing 0.05 M of NaHCO 3 , 0.1 M of NaNCL, 0.02 M of triethanolamine and 0.03% NaN 3 ).
• the liquid chromatography apparatus contains an isocratic pump (Waters 515) whose flow rate is set at 0.8 mL / min.
• the chromatography apparatus also includes a furnace which itself comprises the following column system as standard: a Guard Column Ultrahydrogel Waters type precolumn 6 cm long and 40 mm internal diameter and a linear Waters Ultrahydrogel type column 30 cm long and 7.8 mm inside diameter.
• the detection system consists of an RI Waters 410 type refractometric detector. The oven is brought to a temperature of 60 ° C and the refractometer is brought to a temperature of 45 ° C.
• the chromatography apparatus is calibrated using standards of sodium polyacrylate powder of different molecular masses certified by the supplier: Polymer Standards Service or American Polymers Standards Corporation (molecular mass ranging from 900 to 2.25.10 6 g / mol and polymolecularity index ranging from 1.4 to 1.8).
• the amount of polymer (P) can vary.
• the amount by weight (sec / sec) of polymer (P) used is between 0.05 and 5%, preferably between 0.1 and 2%, relative to the amount of phosphate material.
• the method according to the invention therefore makes it possible to prepare an aqueous suspension of mineral phosphate particles, the extent (S) of the volume distribution of particle sizes [(do , 9 - do , i ) / do , 5] measured by laser diffraction is less than 4.1.
• the invention therefore also provides an aqueous suspension of mineral particles of phosphate material, the extent (S) of the volume distribution of particle sizes [(do, 9 - do , i ) / do , 5] measured by laser diffraction is less than 4.1, comprising at least one anionic polymer (P) with a molecular mass by weight (Mw) of between 1000 and 90,000 g / mol and obtained by polymerization reaction of at least one acid chosen from acrylic acid, acid methacrylic and their salts.
• S volume distribution of particle sizes [(do, 9 - do , i ) / do , 5] measured by laser diffraction is less than 4.1
• P anionic polymer
• Mw molecular mass by weight
• the invention therefore also provides a suspension obtained according to the preparation method according to the invention.
• the particular, advantageous or preferred characteristics of the preparation method according to the invention define suspensions according to the invention which are also particular, advantageous or preferred.
• the grinding method according to the invention therefore makes it possible to control, improve or reduce the extent (S) of the suspension of particles of phosphate material obtained.
• the invention therefore also provides a control method, preferably improvement or reduction, in the extent (S) of the volume distribution of particle sizes [(do , 9 - do , i ) / do , 5 ], measured by laser diffraction, of a suspension of mineral particles of phosphate material, comprising the grinding of at least one phosphate material in the presence of water and of at least one anionic polymer (P) with a molecular mass by weight (Mw) of between 1,000 and 90,000 g / mol and obtained by polymerization reaction of at least one acid chosen from acrylic acid, methacrylic acid and their salts, resulting in an aqueous suspension whose extent (S) is less than 4.1.
• the method of preparing an aqueous suspension of particles of phosphate material comprising the grinding of this material offers many advantages.
• it makes it possible to control or improve the production yield of particles of crushed phosphate material.
• the use of the polymer (P) during the grinding of the phosphate material makes it possible to reduce the extent (S) of the aqueous suspension obtained.
• This suspension having a reduced extent (S) it is possible to limit the quantity of particles whose size is excessive to be used during a subsequent step, for example during a treatment step leading to phosphoric acid. . Particles that are too large must be crushed again.
• the method of preparing an aqueous suspension according to the invention makes it possible to limit the quantity of particles whose size is too small to be used in a subsequent step. Usually, those particles whose size is too small must be removed.
• avoiding re-grinding oversized particles or avoiding removing undersized particles can control or improve the production efficiency of a phosphate material grinding method.
• the invention therefore also provides a method of controlling, preferably improving, the production yield of a method of grinding a phosphate material in the presence of water, comprising the addition during at least one step of grinding, of at least one anionic polymer (P) with a molecular mass by weight (Mw) of between 1000 and 90,000 g / mol and obtained by polymerization reaction of at least one acid chosen from acrylic acid, methacrylic acid and their salts, resulting in a suspension aqueous whose range (S) of the volume distribution of particle sizes [(do, 9 - do , i ) / do , 5], measured by laser diffraction, is less than 4.1.
• P anionic polymer
• Mw molecular mass by weight
• the method of controlling or improving the production yield according to the invention makes it possible to improve the yield by at least 10% by weight of ground particles whose range (S) is less than 4, 1 relative to particles obtained in the absence of polymer (P). According to the invention, such increases in production efficiency of at least 30% or at least 50%, or even at least 80% or at least 100%, are possible.
• the particular, advantageous or preferred characteristics of the preparation method according to the invention define methods of controlling the yield or methods of controlling the extent (S) according to the invention which are also particular, advantageous or preferred.
• the methods of controlling the yield or the methods of controlling the extent (S) according to the invention include the preparation of a suspension of crushed particles having the extent (S) according to the invention.
• the methods for monitoring the yield or the methods for monitoring the extent (S) according to the invention can therefore be defined as methods for preparing a suspension according to the invention.
• An aqueous suspension of phosphate material is prepared by grinding a phosphate rock in the presence of a polymer (PI) or a polymer (P2) defined according to the invention.
• the medium is heated to 95 ° C, then the following elements are added simultaneously and continuously, over 2 hours:
• a polyacrylic acid solution is obtained having an Mw of 5700 g / mol and an Ip of 2.5 (measured by CES).
• Polyacrylic acid solution is treated with:
• the pH of the resulting polymer (PI) is finally adjusted to 8.7 with sodium hydroxide and to a final concentration of 35% dry matter in water.
• the medium is heated to 95 ° C, then the following elements are added simultaneously and continuously, over 2 hours:
• a polyacrylic acid solution is obtained having an Mw of 5700 g / mol and an Ip of 2.5 (measured by CES).
• the polyacrylic acid solution is treated with a 50% by weight aqueous solution of caustic soda in water to achieve a pH value of 8.5.
• the pH of the resulting polymer (P2) is finally adjusted to 8.5 with sodium hydroxide and to a final concentration of 42% dry matter in water.
• the medium is heated to 95 ° C, then the following elements are added simultaneously and continuously, over 2 hours:
• a partially neutralized solution of the copolymer of acrylic acid and maleic acid is obtained.
• the polymer solution is treated with a 50% by weight aqueous solution of caustic soda in water to achieve a pH value of 8.2.
• the solution is then brought to a final concentration of 35% dry matter in water.
• the molecular mass by weight of the polymer thus obtained is approximately 18,000 g / mole and has a polymolecularity index of 3.2.
• Phosphate rock from a mine located in China (Guizhouzhouzhou) was sieved to separate particles larger than 2.5mm in size and to separate particles smaller than 40 ⁇ m in size.
• the sieved rock is then quartered to prepare representative samples with an average mass equal to 320 g ⁇ 4% which are identical in terms of particle size distribution.
• a representative sample is a sample taken in a probabilistic manner such that all the constituent elements of the lot have an equal probability of being selected for the sample.
• the samples are ground individually by means of a ball mill at a solids content of 20% or 40% by weight in a 4 L jar comprising ceramic balls of diameter 19 mm (0.850 L, 1858 g) and ceramic cylinders of dimension 15x15 mm (0.450 L, 965 g) according to the data presented in table 1.
• Aqueous suspensions of phosphate rock are prepared by grinding according to test conditions A and in the presence of polymers (PI), (P2) and (P3) respectively, in an amount by dry / dry weight relative to the amount of rock 0.1%.
• the grinding time is fixed at 2 h and 20 min.
• Measurements of the particle size distribution of the samples are carried out using a laser particle size analyzer (Malvem Mastersizer 2000) and processed with Mastersizer 2000 software version 5.61 (refractive index 1.51, pump speed: 1250 rpm, pump speed. mixer: 750 rev / min, ultrasonic agitation at 50% power during measurement). Seven measurements spaced 10 s are carried out by aliquot. Three washing cycles are carried out between each series of three measurements.
• polymers (PI), (P2) and (P3) allows excellent control of the particle size of the suspensions prepared as well as reaching a range (S) well below 4.1.
• aqueous suspensions of phosphate rock are prepared by grinding according to test conditions A in the absence of polymer and in the presence of polymer (PI) in an amount by dry / dry weight relative to the amount of rock of 0 , 1%.
• the target particle size of 0.5 is less than 200 ⁇ m (198 ⁇ m ⁇ 1.5%).
• the use of the polymer (PI) allows a much lower range (S) to be achieved compared to the preparation of a suspension in the absence of polymer. In addition, the time required to achieve this result is reduced by more than 40%.
• aqueous suspensions of phosphate rock are prepared by grinding according to test conditions B in the absence of polymer and in the presence of polymer (PI) in an amount by dry / dry weight relative to the amount of rock of 0 , 2%.
• the target particle size of 0.5 is less than 200 ⁇ m (198 ⁇ m ⁇ 1.5%).
• the method according to the invention allows the preparation of an aqueous suspension of phosphate material according to the invention which is particularly effective in achieving the target particle size values and in controlling the extent (S) for different levels of solid during grinding.
• the extent (S) and the grinding times are particularly reduced thanks to the use of polymers (P).

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• 2020
  • 2020-02-06 FR FR2001181A patent/FR3106990B1/fr active Active
• 2021
  • 2021-02-03 WO PCT/FR2021/000008 patent/WO2021156551A1/fr unknown
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