Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
  • B09C—RECLAMATION OF CONTAMINATED SOIL
  • B09C1/00—Reclamation of contaminated soil
  • B09C1/08—Reclamation of contaminated soil chemically
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
  • C04B28/06—Aluminous cements
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
  • C04B28/02—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing hydraulic cements other than calcium sulfates
  • C04B28/06—Aluminous cements
  • C04B28/065—Calcium aluminosulfate cements, e.g. cements hydrating into ettringite
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B7/00—Hydraulic cements
  • C04B7/32—Aluminous cements
  • C04B7/323—Calcium aluminosulfate cements, e.g. cements hydrating into ettringite
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
  • B09C—RECLAMATION OF CONTAMINATED SOIL
  • B09C2101/00—In situ
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
  • C04B2111/00767—Uses not provided for elsewhere in C04B2111/00 for waste stabilisation purposes
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
  • C04B2111/10—Compositions or ingredients thereof characterised by the absence or the very low content of a specific material
  • C04B2111/1075—Chromium-free or very low chromium-content materials
  • C04B2111/1081—Chromium VI, e.g. for avoiding chromium eczema
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P40/00—Technologies relating to the processing of minerals
  • Y02P40/10—Production of cement, e.g. improving or optimising the production methods; Cement grinding
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
  • Y02W30/00—Technologies for solid waste management
  • Y02W30/50—Reuse, recycling or recovery technologies
  • Y02W30/91—Use of waste materials as fillers for mortars or concrete

Definitions

• the present invention relates to a process for treating soil polluted, in particular with anions such as sulfate ions and with heavy metal cations, characterized in that it comprises at least the treatment of the soil with a first mineral binder of sulfoaluminous clinker type, lime and an additional component chosen from a second inorganic binder different from the first inorganic binder, an alkanolamine, a reducing agent of a hexavalent chromium salt and their combination (s).
• a subject of the present invention is also the product capable of being obtained by said process as well as a composition for treating polluted soil comprising a first inorganic binder of sulfoaluminous clinker type, lime, and an additional component chosen from a second binder.
• mineral different from the first inorganic binder an alkanolamine, a reducing agent of a hexavalent chromium salt and their combination (s), and the use of said composition for the treatment of a polluted soil.
• Soil decontamination is a growing demand and comes with major challenges in terms of public health and environmental protection.
• the builder is required to treat the excavated soil before putting it in landfill.
• the landfill of contaminated soils first requires lowering the dangerousness class of these soils, which amounts to lowering the level of leachable pollutants in the water.
• the present invention relates to a composition for the treatment of polluted soils and to a process for the treatment of polluted soils using such a composition making it possible to obtain both short-term efficiency, with trapping of sulphates from 1 day. , and durability over time of this trap, including more than 2 months after treatment.
• the release of chromate ions in the short term and in the long term (2 months or 6 months) is also controlled and improved within the framework of the invention.
• the primary compounds are represented by C for CaO, S for S1O 2 , A for AI 2 O 3 , $ for SO 3 , F for Fe 2 C> 3 , T for T1O 2 , which will be used in the throughout this text, unless otherwise indicated.
• clinker is meant according to the invention the product obtained after cooking (clinkerization) of a mixture (raw) composed, inter alia, for example of limestone and for example of clay for Portland clinker.
• the sulfoaluminate phase optionally doped with iron, has the formula C4AxFy $ z with x varying from 2 to 3, y varying from 0 to 0.5 and z varying from 0.8 to 1, 2.
• the yeelimite or ye'elimite is a sulfoaluminate phase. It is a calcium sulfoaluminate of formula Ca 4 (AI0 2 ) 6 SC> 3 (hereinafter referred to as “C4A3 $”).
• Belite is a dicalcium silicate of formula Ca2SiC> 4 (hereinafter referred to as “C2S”). Belite exhibits different varieties of polymorphisms: C2S (a ’), orthorombic crystal, C2S (a), hexagonal crystal, 028 (b), monoclinic crystal, C2S (y), orthorombic crystal.
• C2S dicalcium silicate of formula Ca2SiC> 4
• Belite refers to any crystalline form of belite.
• Ferrites are phases comprising iron oxide.
• the ferrites are a calcium aluminoferrite phase corresponding to the general formula C2Ax'F (1-x '), with x' ranging from 0.2 to 0.8.
• the ferrites preferably comprise a brownmillerite phase.
• the brownmillerite is a ferro-aluminate tetracalcium of formula Ca 4 Al 2 Fe 2 0io (hereinafter referred to as "C 4 AF”)
• C 4 AF ferro-aluminate tetracalcium of formula Ca 4 Al 2 Fe 2 0io
• the ferrites may also comprise a so-called ferroperovskite phase.
• Ferroperovskite is a perovskite phase integrating iron, which gives a compound of variable composition, in particular of formula C3FT.
• Mayenite is an anhydrous calcium aluminate of formula 12Ca0.7Al 2 C> 3 (hereinafter referred to as "C12A7") and exhibits a crystal structure composed of three-dimensionally bonded voids (cages) comprising "free oxygen ions". These free oxygen ions can be substituted by anions at room temperature.
• the C12A7 phase encompasses any isotype structure of C12A7, such as for example C11A7.CaF2 (F here denotes fluorine) whose structure results from a substitution of O 2 - ions by F - ions. .
• C11A7.CaF2 F here denotes fluorine
• Quicklime is the direct product of the thermolysis or calcination of limestone. It mainly contains calcium oxide (CaO).
• Slaked lime is obtained after hydration of quicklime. It includes calcium hydroxide Ca (OH) 2.
• a mineral binder is a mineral material having the property of solidifying and then of hardening while acquiring mechanical characteristics.
• a mineral binder can be a hydraulic binder and / or a latent hydraulic binder and / or a binder having pozzolanic properties.
• a hydraulic binder is a material having the property of hydrating in the presence of water and the hydration of which makes it possible to obtain a solid with mechanical characteristics.
• a latent hydraulic binder and a pozzolanic binder have the property of hydrating in the joint presence of water and lime.
• long term corresponds to “at least 2 months”, advantageously “at least 6 months”.
• short term corresponds to “from 1 to 7 days”.
• the subject of the invention is a method for treating polluted soil comprising at least treating the soil with, by weight relative to the weight of said dry soil:
• a second mineral binder different from the first mineral binder preferably chosen from a cement of calcium aluminates, a blast furnace slag or their combination, in a content ranging from 1.5% to 5.0% by weight relative to the weight of said dry soil,
• a belitic sulfoaluminous clinker is a clinker comprising at least one sulfoaluminate phase, in particular C4A3 $ yeelimite, and a C2S belite phase in proportions in these two phases of more than 60% by weight relative to the total weight of said belitic sulfoaluminous clinker.
• the belitic sulfoaluminous clinker preferably comprises at least 30% by weight relative to the total weight of said sulfoaluminate phase clinker, in particular yeelimite, more preferably at least 35%. It comprises in particular at least 15% by weight relative to the total weight of said belite phase clinker, more particularly at least 20% by weight.
• the belitic sulfoaluminous clinker comprises less than 65%, preferably less than 60%, more preferably less than 50%, by weight relative to the total weight of said clinker of sulfoaluminate phase, advantageously yeelimite. More particularly, the belitic sulfoaluminous clinker comprises between 30 and 65%, preferably between 30% and 60%, more preferably between 35% and 50%, by weight relative to the total weight of said sulfoaluminate phase clinker, such as yeelimite.
• the belitic sulfoaluminous clinker also comprises more than 15% by weight relative to the total weight of said belite phase clinker.
• the belitic sulfoaluminous clinker comprises at least 2% by weight relative to the total weight of said belite phase clinker in alpha ’form.
• the belitic sulfoaluminous clinker comprises at least 2% by weight relative to the total weight of said belite phase clinker in alpha ’form and the belite phase complement in another form.
• the belitic sulfoaluminous clinker comprises between 15 and 35%, preferably between 20% and 35%, by weight relative to the total weight of said belite phase clinker, including in particular at least 2% by weight relative to the total weight of said belite phase clinker in alpha 'form.
• the belitic sulfoaluminous clinker further comprises more than 12% by weight, more preferably more than 15% by weight, more preferably more than 20% by weight relative to the total weight of the ferrite clinker, more preferably between 20% and 40%. %.
• the belitic sulfoaluminous clinker comprises, by weight relative to the total weight of said clinker:
• the belitic sulfoaluminous clinker comprises, by weight relative to the total weight of said clinker:
• the belitic sulfoaluminous clinker comprises less than 5% by weight relative to the total weight of said mayenite clinker.
• the belitic sulfoaluminous clinker does not include a mayenite phase detectable by Rietveld analysis of the X-ray diffraction spectrum of the clinker.
• the belitic sulfoaluminous clinker comprises at least 80% by weight relative to the total weight of said clinker of sulfoaluminate phases, preferably yeelimite C4A3 $, belite C2S and ferrites, preferably at least 90%, more preferably at least 95%.
• this type of clinker has on the one hand the advantage of having lower chromium contents (because their manufacture requires less bauxite, which is the raw material which provides the most chromium in the clinker) and on the other hand to have sufficient reactive constituents in the short term (yeelimite) and long term (belite and ferrite).
• bauxite which is the raw material which provides the most chromium in the clinker
• clinkers B1, B2 and B3 having the following mineralogy:
• the Blaine specific surface area of the belitic sulfoaluminous clinker according to the invention is between 2500 cm 2 / g and 6000 cm 2 / g.
• Belitic sulfoaluminous clinker is mixed with the polluted soil in proportions varying from 1.5 to 5% by weight relative to the weight of the dry soil, preferably from 1.5 to 4%, more preferably from 1.5 to 3%.
• the lime can be free lime (CaO), slaked lime (Ca (OH) 2), or a mixture of free lime and slaked lime in any proportion.
• the lime is slaked lime.
• the lime is mixed with the polluted soil in proportions varying from 2.0 to 5.0% by weight relative to the weight of the dry soil, preferably from 3 to 5%.
• Lime is added in proportions greater than 30% by weight relative to the total weight of the first inorganic binder, lime, and optionally of the second inorganic binder, preferably greater than 50%, and more preferably up to 80 %.
• the durability of the treatment is less because it must be taken into account that part of the lime will interact with the soil (cationic exchanges between Ca 2+ which comes from the lime and the ions present in the interfoliar space of clay minerals present in the soil). Part of the lime will therefore not be available to react with the clinkers and sulphates.
• the additional component is chosen from a second inorganic binder different from the first inorganic binder, an alkanolamine, a reducing agent of a hexavalent chromium salt, and their combination (s).
• the additional component can be an inorganic binder different from the first inorganic binder.
• the second inorganic binder different from the first inorganic binder, is preferably a hydraulic binder and / or a latent hydraulic binder and / or a binder having pozzolanic activity. It can be a calcium aluminate cement or a mineral addition chosen from a blast furnace slag, fly ash, calcined clays and their combinations, or the combination of a calcium aluminate cement and said mineral addition. . More particularly, the second inorganic binder is calcium aluminate cement or blast furnace slag or a combination thereof.
• the second inorganic binder is mixed with the polluted soil in proportions varying from 1.5 to 5% by weight relative to the weight of the dry soil, preferably from 1.5 to 4%, more preferably from 1.5 to 3%.
• the mass proportion between first and second mineral binder mixed with the polluted soil is between 30/70 and 70/30, more particularly 40/60 and 60/40, preferably 50/50.
• the second inorganic binder is a calcium aluminate cement.
• a calcium aluminate cement is a cement comprising at least one phase chosen from C3A, CA, C12A7, C11A7CaF2, C4A3 $ (yeelemite), C2A (1-x) Fx (with x belongs to] 0, 1]), hydraulic amorphous phases having a C / A molar ratio of between 0.3 and 15 and such that the cumulative Al 2 O 3 contents of these phases are between 3 and 70% by total weight of the calcium aluminate cement, preferably between 7 and 50% by weight and better still between 20 and 30% by weight.
• the calcium aluminate cement comprises more than 60%, preferably more than 80%, by mass of Mayenite C12A7 phase or of a Mayenite isotype.
• the calcium aluminate cement of the invention comprises, as the sole aluminate phase, the Mayenite C12A7 phase.
• the calcium aluminate cement advantageously comprises more than 85% by mass of Mayenite phase, more advantageously more than 90% by mass of Mayenite phase, even more advantageously more than 95% by mass of Mayenite phase.
• the calcium aluminate cement can comprise up to 99% by mass of Mayenite phase, or even 100% by mass. Clinkers richer in C12A7 allow more ettringite to be formed.
• the calcium aluminate cement of the invention is advantageously obtained by melting or sintering between 1250 and 1300 ° C approximately of a mixture of white bauxite and limestone.
• Low levels of silica and iron in the raw materials guarantee an optimal level of C12A7.
• the cumulative content of iron and silica is less than 30%, even more advantageously less than 20%, by weight relative to the total weight of the raw materials.
• the second mineral binder is a mineral addition chosen from a blast furnace slag, fly ash, calcined clay, and their combinations, in particular a blast furnace slag.
• a blast furnace slag is a by-product of smelting resulting from the reduction of iron ores by coke. It is a mixture composed essentially of silicates, aluminates and lime, with various metal oxides, with the exception of iron oxides. It is as defined in the “Cement” standard NF EN 197-1 paragraph 5.2.2 of April 2012.
• the blast furnace slag is ground with a particle size of between 3 and 50 pm.
• Fly ash is siliceous or calcic in nature. They are obtained by precipitation of pulverulent particles in the flue gases of the boilers supplied with pulverized coal. They are as defined in the “Cement” standard NF EN 197-1 paragraph 5.2.4 of April 2012.
• Calcined clay is produced in a kiln at a temperature of around 800 ° C. It is as defined in the “Cement” standard NF EN 197-1 of April 2012.
• the additional component can also be an alkanolamine.
• An alkanolamine is an alkane comprising at least one amine function and at least one alcohol function.
• the alkane is a C2-C6 alkane, preferably a C3-C5 alkane.
• the alkanolamine is selected from the group comprising N, N bis- (2-hydroxyethyl) -2-propanolamine) (DIEPA), N, N bis- (2-hydroxypropyl) -N- (hydroxyethyl) amine (EDIPA), diethanolamine (DEA), triethanolamine (TEA), triisopropanolamine (TIPA), N- (hydroxyethyl) diethylenetriamine (HEDETA), aminoethylethanolamine (AEEA) and their combination (s).
• DIEPA N, N bis- (2-hydroxyethyl) -2-propanolamine)
• EDIPA N, N bis- (2-hydroxypropyl) -N- (hydroxyethyl) amine
• DEA diethanolamine
• TIPA triethanolamine
• TIPA triisopropanolamine
• HEDETA hydroxyethyl) diethylenetriamine
• AEEA aminoethylethanolamine
• the alkanolamine is a tri (hydroxyalkyl) amine, more particularly, a tri (hydroxyalkyl) amine having at least one hydroxyalkyl group comprising 3 to 5 carbon atoms.
• the alkanolamine is chosen from triethanolamine, triisopropanolamine and their combination.
• the possible presence in the binder of such a component makes it possible to increase the effectiveness of the treatment in the medium and long term by optimizing the reactivity of the aluminate phases.
• the alkanolamine is preferably mixed with the polluted soil at a dosage by weight relative to the weight of said dry soil of between 0.001 and 0.050%.
• the additional component may also be a reducing agent for a hexavalent chromium salt, in particular calcium nitrite, or a reducing agent for a hexavalent chromium salt based on antimony.
• the reducing agent for a hexavalent chromium salt is calcium nitrite.
• the reducing agent for a hexavalent chromium salt is a reducing agent for an antimony-based hexavalent chromium salt.
• the reducing agent of a hexavalent chromium salt is mixed with the polluted soil at a dosage of between 0.01% and 3.0% by weight relative to the weight of said dry soil.
• a dosage of between 0.01% and 3.0% by weight relative to the weight of said dry soil in the presence of belitic sulfoaluminous clinker, it is not easy to control the release of chromate ions. It is therefore possible to use components which make it possible to reduce the part of chromium VI in chromium III which is stable and non- toxic.
• Sulphate-based reducing agents such as FeSCL and SnSCL are not recommended, so as not to provide additional sulphates.
• Other chlorine-based reducing agents should be avoided because they interfere with the action of the sulfoaluminous belitic clinker and greatly reduce the effectiveness of the treatment.
• Antimony-based reducing agents perform well in this regard.
• the additional component can be a combination of an inorganic binder other than the first binder, an alkanolamine and / or a reducing agent of a hexavalent chromium salt.
• the additional component can be a combination of an inorganic binder different from the first binder and of an alkanolamine.
• the additional component can also be a combination of an inorganic binder different from the first binder and a reducing agent of a hexavalent chromium salt.
• the effectiveness of the treatment can be significantly improved in the short and long term by adding water during the treatment.
• the binder is evenly distributed and the amount of water in the soil to be treated is sufficient to optimize the formation of ettringite.
• a water content which can be between 5% and 40% by weight, more advantageously 15% and 40%, relative to the weight of the dry soil, depending on its nature. If necessary, water can be added to the soil. The amounts of water are sufficient to allow the hydration reaction, and can easily be determined by one skilled in the art.
• the soil to be treated is non-inert and naturally or artificially contains leachable sulphates (from 1000 to 15000 ppm). It is taken as is, and usually has a humidity of 10 to 40%.
• the constituents of the treatment namely the first mineral binder, lime and the additional component chosen from a second mineral binder different from the first mineral binder, an alkanolamine, a reducing agent of a hexavalent chromium salt and their combination (s) ( s) can be added simultaneously, consecutively or sequentially and separately to the polluted soil to be treated.
• a composition comprising the first inorganic binder, the additional component chosen from a second inorganic binder different from the first inorganic binder, an alkanolamine, a reducing agent of a hexavalent chromium salt and their combination (s) ) and optionally the lime can be prepared beforehand and then added to the polluted soil to be treated.
• the composition can be prepared by separate grinding of each of its constituents and then mixing all the constituents or by mixing the constituents and then co-grinding all the constituents.
• the hydraulic binder can be ground and / or separated from the lime in order to obtain a binder having a Blaine specific surface area of between 2500 cm 2 / g and 6000 cm 2 / g.
• Water can be added to the soil or be introduced at the same time or after addition of the constituents of the treatment.
• the soil is also mixed with water at a dosage of between 1% and 15% by weight based on the weight of the dry soil.
• the soil is mixed with each of the constituents of the treatment.
• the method of treating polluted soil comprising at least one step of mixing the soil with, by weight relative to the weight of said dry soil:
• the soil is mixed with the constituents of the treatment for a sufficient time in any suitable container.
• the mixing can be carried out continuously or discontinuously, in particular the mixing is carried out continuously.
• Mixing can be carried out with an open or closed type mixer.
• the terms “mixed” and “mixed” are used interchangeably.
• the present invention also relates to the use of the process according to the invention for the stabilization in situ or before storage of soil polluted in particular by sulphate anions and / or heavy metal cations, in particular in the long term, more particularly in the long term. short and long term.
• composition for the treatment of polluted soil Composition for the treatment of polluted soil
• the present invention also relates to a composition for the treatment of polluted soil, comprising, in percentage by mass:
• the composition for the treatment of polluted soil comprising, in percentage by mass:
• the belitic sulfoaluminous clinker comprises more than 12% by weight relative to the total weight of the ferrite clinker, preferably more than 15%, preferably more than 20%, more advantageously between 20% and 40%.
• the belitic sulfoaluminous clinker comprises at most 5% by weight relative to the total weight of the Mayenite clinker.
• the belitic sulfoaluminous clinker does not include a Mayenite phase detectable by Rietveld analysis of the X-ray diffraction spectrum of the clinker.
• the second inorganic binder is a calcium aluminate cement or a mineral addition chosen from a blast furnace slag, fly ash, calcined clays and their combinations, or the combination of a calcium aluminate cement. and said mineral addition. More particularly, the second inorganic binder is calcium aluminate cement or blast furnace slag or a combination thereof.
• the second inorganic binder is a calcium aluminate cement, preferably comprising more than 60%, preferably more than 80%, by mass of Mayenite C12A7 phase or of a Mayenite isotype.
• the second mineral binder is a mineral addition chosen from a blast furnace slag, fly ash, calcined clays and their combinations, in particular a blast furnace slag.
• the alkanolamine is a tri (hydroxyalkyl) amine, more advantageously chosen from triethanolamine, triisopropanolamine and their combinations.
• the reducing agent for a hexavalent chromium salt is selected from calcium nitrite, a reducing agent for a hexavalent chromium salt based on antimony, and combinations thereof.
• Lime is present in the composition in proportions greater than 30% by weight relative to the total weight of the first inorganic binder, lime, and optionally of the second inorganic binder, preferably greater than 50%, and more preferably up to 'to 80%.
• lime is slaked lime, or a mixture of free lime and slaked lime in any proportion.
• the lime is slaked lime.
• compositions as defined above for the treatment of soils polluted with anions, in particular sulphates, and with heavy metal cations, in particular hexavalent chromium salts, and their mixture.
• the quantitative mineralogical analysis of a clinker is carried out by Rietveld analysis of the X-ray diffraction spectrum of this clinker.
• the clinker sample to be analyzed is finely ground to provide a sample in which all the particles pass through a sieve with a mesh size of 63 ⁇ m.
• the reference X-ray diffraction spectra of the crystal phases present in the sample to be analyzed are obtained from pure samples of these phases.
• the tests are carried out on a material in which at least 95% of the particles (by mass) have a size of less than 4 mm.
• the mass of dry matter (DM) of the sample is determined after passing in an oven at 105 ° C ⁇ 5 ° C until constant weight in accordance with ISO 11465, August 1994.
• the difference between the masses of the sample before and after the passage in the oven corresponds to the moisture content of the soil or water content, which is expressed in relation to the mass of dry soil, as defined in standard NF EN 12457-2: 2002.
• test portion of a total wet mass containing exactly 0.090 kg ⁇ 0.005 kg (measured with an accuracy of 0.1 g) of dry matter is prepared.
• the leaching test is carried out at room temperature, i.e. 20 ° C ⁇ 5 ° C.
• the wet test portion with a total mass corresponding to 0.090 kg ⁇ 0.005 kg of dry matter is placed in a flask, then a quantity of lixiviant is added (distilled water, demineralized water, deionized water or water of equivalent purity having a pH between 5 and 7.5, conductivity less than 0.5 mS / m) allowing a liquid-solid ratio of 10 L / kg ⁇ 2% to be obtained.
• the stoppered vial is placed in a stirring device (as defined in the standard) is stirred at about 10 rpm for 24 hours ⁇ 0.5 h. To achieve a good chemical balance between the solid and the solution, during the extraction it is important to avoid the settling of the solids.
• the suspended solids are decanted for 15 minutes ⁇ 5 min, then vacuum filtered through a 0.45 ⁇ m membrane filter.
• the eluate can be centrifuged at 2000g for 30 minutes to prevent clogging of the 0.45 ⁇ m filter.
• the conditions are specified in standard NF EN-12457-2, December 2002.
• the eluate is then divided into an appropriate number of sub-samples for the various chemical analyzes and stored according to standard EN ISO 5667-3.
• Analysis of the eluate produced by the leaching test provides the concentration of the constituents in the eluates expressed in mg / L. The final results are expressed as the quantity of constituent leached relative to the total mass of the sample, in mg / kg of dry matter.
• the amount of a constituent leached from the material is calculated using the following formula:
• C is the concentration of a particular constituent in the eluate (expressed in milligrams per liter);
• L is the volume of leachate used (expressed in liters);
• TH 100 (MH-MS) / MS
• MS is the mass of the dry test portion expressed in kilograms
• MH is the mass of the non-dried test portion expressed in kilograms
• the anion analysis is carried out by ion chromatography eluting with solutions of 1 mM NaHCCh and 3.5 mM Na2CC> 3. Standard solutions for the F, Cl, NO, NO3, Br, PO4 2 , and SO4 2 ions are prepared.
• the effectiveness in stabilizing sulfates is measured after 1 day of treatment for up to 2 or 6 months.
• Heavy metal analysis The analysis of the elements (heavy metals) is carried out by ICP-AES analysis (Atomic Emission Spectrometry coupled to an induced plasma).
• RF power 1.3 kW Plasma flow rate: 15 L / min Auxiliary flow rate: 2.25 L / min Nebulizer flow rate: 0.8 L / min Reading time per replica: 20 s
• ND Not Detectable, i.e. below the detection threshold of the measurement NM: Not measured
• the two soils are loamy soils from the Paris region near Guerville, and naturally contain sulphates (between 9000 to 12000 ppm leachable sulphates according to the NF EN 12457-2 leaching test with a liquid / solid ratio (L / S) of 10). Their water content is 20% compared to dry soil. List of constituents
• ROLAC-OB contains 72% blast furnace slag, 25% Portland clinker and 3% secondary constituents authorized according to standard NF EN 197-1.
• wet soil equivalent to 600 g of dry soil is introduced into a Perrier type mixer.
• wet we mean the natural soil moisture possibly adjusted to optimize the hydration of the binder (amount of water extractable by evaporation during baking at 105 ° C to constant weight).
• the water content can be between 5% and 40% of the weight of the soil, depending on its nature.
• the formula for the treatment is introduced on the surface and then the whole is mixed, at low speed, for at least 2 minutes until a mixture is obtained which is homogeneous in color and texture.
• the maturation of the treated soil is carried out over a period of 2 hours, 1 day, 7 days, 1 month, 2 months or 6 months at room temperature.
• Example 1.1 is a control test.
• Examples 1.2 and 1.4 are comparative tests.
• the treatment with the combination of a sulphoaluminous belitic clinker, lime and a calcium aluminate cement improves the long-term performance of the treatment compared to a combination of a belitic sulphoaluminous clinker. and lime (1.2 and 1.4) whether for the release of sulfate ions or the release of chromate ions.
• Example 2.0 is a control test.
• Example 2.1 is a comparative test.
• Examples 2.2 to 2.7 are tests according to the invention.
• Stabilization of sulfates can be significantly improved with the addition of Tl PA or TEA to the binder. Their presence also has a surprisingly positive impact in limiting the release of chromium.
• Example 3.0 is a control test.
• Example 3.1 is a comparative test.
• Examples 3.2 and 3.3 are tests according to the invention.
• the treatment with the combination of a sulphoaluminous belitic clinker, lime and a reducing agent of a hexavalent chromium salt makes it possible to reduce the release of sulphate ions and chromate ions at 1 month and 2 month.
• Example 4.0 is a control test.
• Examples 4.1, 4.5 and 4.6 are comparative tests.
• Examples 4.2, 4.3, 4.4, 4.7 and 4.8 are tests according to the invention.
• the performance of the treatment is significantly improved with the addition of blast furnace slag with 2.5% B3 clinker mixed with 3.33% slaked lime (4.2 vs 4.1), or 3% B3 clinker. mixed with 4% slaked lime (4.7 vs 4.6).
• the stabilization of sulphates is improved, and the amounts of chromium released are much less than 0.5 ppm up to 2 months.
• the slag is effective whether it is added as it is or in a road binder (4.4).
• the addition of water during the treatment makes it possible to further improve the efficiency of the treatment (4.3 and 4.8).

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• 2019
  • 2019-12-23 FR FR1915469A patent/FR3105032B1/fr active Active
• 2020
  • 2020-12-23 WO PCT/EP2020/087789 patent/WO2021130327A1/fr unknown
  • 2020-12-23 EP EP20839098.9A patent/EP4081492A1/de active Pending

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