Use of clinker for treating pulverulent materials with a high soluble fraction with a view to storing same

Abstract

The present invention relates to a method for treating a pulverulent material, such as waste from the purification of incineration fumes, by means of a clinker, in order to obtain a solid stabilised product that is storable. The method provides a new way of upgrading clinker.

Description

Description Title: Use of clinker for the treatment of powdery materials with a high soluble fraction for storage Technical field

[0001] This disclosure relates to the field of treatment of products from waste incineration for storage, in particular the treatment of residues from flue gas purification, in particular from incineration for storage. Prior art

[0002] Managing fumes emitted into the atmosphere is a major environmental challenge. In particular, the management of waste from residential, institutional, and commercial sources, as well as agricultural waste and other wastes such as sewage sludge, is a challenging issue for which solutions are constantly evolving.

[0003] Currently in France, incineration is the second most common method of waste disposal. The incineration process results in a reduction in the volume and mass of solid waste; however, incineration generates, among other things, smoke containing acid gases, fly ash, clinker, and sewage residues. The smoke must be purified before being released into the atmosphere; fly ash and sewage residues must be treated before being stored.

[0004] As illustrated in Fig. 1, an incineration plant comprises, among other things, an incineration furnace 1, a fly ash storage unit 3, a cooling tower 7, a flue gas treatment unit 9, a storage unit 12, an optional catalytic treatment unit and a chimney (not shown in Fig. 1).

[0005] Incinerator 1 incinerates waste, produces fly ash and clinker, and emits smoke.

[0006] Fly ash and clinker are collected separately and then transported, respectively, to: - a fly ash storage unit 3 via a fly ash pipe 2, and - a clinker storage unit 5 via a clinker pipe 4.

[0007] The flue gas is conveyed via a pipe 6 to the cooling tower 7 to produce cooled flue gas. This cooled flue gas is conveyed via a cooled flue gas pipe 8 to the flue gas treatment unit 9, the objective of which is that the flue gas complies with the regulatory atmospheric discharge thresholds. In this flue gas treatment unit 9, the cooled flue gas is brought into contact with a flue gas treatment material, such as sodium bicarbonate, soda or lime, in order to neutralize acid gases, such as SO2 and HCl, to produce purified flue gas and solid residues comprising soluble fractions such as NaCl, KCl, Na2SO4, KsNa(SO4)2 and CaCl(OH). The contacting with the flue gas treatment material, such as soda, sodium bicarbonate or lime, can be carried out dry or in wet conditions, preferably dry. For example, it is carried out dry in the case of sodium bicarbonate or dry or in wet conditions in the case of lime.

[0008] After separation with a bag filter, the purified smoke is recovered in the purified smoke pipe 10 to be discharged into the atmosphere via the chimney and the solid residues are conveyed via a solid residue pipe 11 to the storage unit 12.

[0009] Before being discharged into the atmosphere, the purified flue gas may undergo an additional purification step in the optional catalytic treatment unit to obtain optional solid residues and highly purified flue gas which is discharged into the atmosphere via the stack. The optional solid residues are then conveyed to the storage unit 12. The solid residues and, possibly, the optional solid residues, stored in the storage unit 12 are the incineration flue gas purification residues.

[0010] Thus, an incineration plant can produce the following three different solid materials: - fly ash, produced in incineration furnace 1 and stored in fly ash storage unit 3, - the clinker, produced in incineration furnace 1 and stored in clinker storage unit 5, and - the residues from the purification of incineration fumes, produced in the fume treatment unit 9 and optionally in the catalytic treatment unit and stored in the storage unit 12.

[0011] Table 1 below shows the weight content of major salts in the soluble fraction present in three examples of incineration flue gas purification residues obtained by treatment with sodium bicarbonate or lime and in one example of fly ash. Major salts are those whose weight content is greater than 4% relative to the total dry weight of the residue or fly ash.

[0012] Table 1 highlights that the composition of these two types of powdered materials is quite different. In fact, in a purification residue, the weight content of the soluble fraction in relation to the total dry weight of said residue is greater than 30%. On the other hand, in fly ash, the weight content of the soluble fraction relative to the total dry weight of said fly ash is less than 20%. The weight content of the soluble fraction is calculated by adding the weight contents of each major salt present in said soluble fraction.

[0013] Furthermore, the person skilled in the art knows that K3Na(SC )2 and a high NaCI content are markers of sodium bicarbonate treatment while CaCI(OH) is a marker of lime treatment.

[0014] [Table 1]

[0015] Two main directives constitute the second level of European waste legislation and focus on the treatment of incineration flue gas treatment residues: the Industrial Emissions Directive (Waste Incineration) and the Landfill (Storage) Directive. European Directive No. 1999 / 31 / EC of 26 / 04 / 99 on the landfill of waste introduces the concept of treatment before storage. The French ministerial decree of 30 / 12 / 2002, as amended, relating to the storage of hazardous waste imposes various limits on the storage input. For example, it imposes a limit of 10% on the soluble fraction in the leachate obtained from the residues of incineration fume purification.

[0016] Thus, before their storage, legislation requires that the residues from the purification of incineration fumes be stabilized, i.e. treated to respect the imposed limit of soluble fraction in the leachate. As described in "FNADE ADEME Study - Feedback on the French sector - Stabilization / solidification - Storage of hazardous waste" published in 2006, incineration flue gas purification residues are traditionally stabilized by mixing with a hydraulic binder. The current hydraulic binder is generally a mixture of cement, meta kaolin and blast furnace slag. The treated residues obtained, commonly called stabilized solid products, are then stored in specifically designed cells, at a temperature below 60°C, as required by current regulations.

[0017] The bottom ash is classified into 2 types: - household waste incineration bottom ash (MIDND), which is non-hazardous waste, and - hazardous waste incineration bottom ash (MIDD), which is hazardous waste.

[0018] Currently, in France, MIDNDs are only used for the manufacture of road sub-bases. This use is interesting but poses a problem of temporary storage. and a problem of permanent storage of clinker. The problem of temporary storage arises from the fact that clinker is produced continuously while roads are produced periodically. It is therefore necessary, between two periods of road production, to temporarily store the clinker produced in a specifically dedicated facility before using it. The problem of permanent storage results from the fact that the quantity of clinker produced is greater than the need for the manufacture of road sub-base.

[0019] MIDDs are not recovered but simply stored permanently under appropriate conditions after analysis.

[0020] Thus, a significant proportion of MIDND and MIDD are not recovered but are stored in specifically dedicated facilities. This storage has a significant impact because it significantly reduces the available excavation space. However, preserving the available excavation space is a major issue and reducing the pressure on the available excavation space is necessary.

[0021] There is therefore a need to provide a solution to reduce the strain on the available excavation space. Summary

[0022] This disclosure improves the situation.

[0023] A method is provided for treating a powdery material with a high soluble fraction with a stabilizing mineral binder to obtain a solid stabilized product, said method comprising the following steps: a) bringing the powdery material, the stabilizing mineral binder and water into contact to obtain a mixture; and b) solidifying and stabilizing the mixture to obtain the solid stabilized product, characterized in that the stabilizing mineral binder comprises cement and clinker.

[0024] The mineral binder can be chosen from a hydraulic binder or a pozzolanic binder.

[0025] Advantageously, the solid stabilized product obtained by the process of the present invention complies with the regulations on storage because it respects the limit of soluble fraction in the leachate imposed by the French ministerial decree of 30 / 12 / 2002 amended relating to the storage of hazardous waste.

[0026] Thus, the process of the present invention offers a new way of recovering household waste incineration bottom ash (MIDND) which makes it possible to address their storage problem. Indeed, this new recovery method makes it possible to reduce the quantity of MIDND not recovered and stored permanently. Thus, the quantity of MIDND to be stored permanently is reduced. In addition, the method of the present invention can be carried out continuously because the production of the powdery material, such as a flue gas cleaning residue, in particular incineration, is continuous and therefore the need to stabilize the soluble fraction of the powdered material is also continuous. Thus, the amount of MIDND to be temporarily stored is reduced.

[0027] Furthermore, the clinker of the mineral binder may be a hazardous waste incineration clinker (HWI). The method of the present invention therefore makes it possible to use HWI, whereas currently these are stored separately. Advantageously, the method of the present invention makes it possible to store HWI after having used them as a stabilizing agent for the powdered material with a high soluble fraction. In other words, the method of the present invention uses a hazardous waste, HWI, to treat another hazardous waste and obtain a solid stabilized waste that complies with the regulations on storage.

[0028] Thus, thanks to these new recovery methods, the process of the present invention is an ecological solution making it possible to reduce the strain on the available excavation space.

[0029] Furthermore, the Applicant noted that, while complying with the legislation, the process of the present invention makes it possible to effectively stabilize a greater quantity of powdered material with a high soluble fraction than the process using a current hydraulic binder comprising a mixture of cement, meta kaolin and blast furnace slag.

[0030] Without wishing to be bound by any theory, the inventors are of the opinion that this increase in the quantity of stabilized powdery material with a high soluble fraction can be explained by the physicochemical properties of the clinker. Indeed: - the granular aspect of the clinker could allow an improvement in the mechanical properties of the solid stabilized product; and - molecules comprising iron, molecules comprising aluminum, molecules comprising calcium and molecules comprising silicon of the clinker could be involved in the reactions stabilizing the soluble fraction in the solid stabilized product.

[0031] The inventors also noted that, unexpectedly, the mechanical properties of the solid stabilized product obtained by the process of the present invention are equivalent to the mechanical properties of the solid stabilized product obtained from the current hydraulic binder, whereas the solid stabilized product obtained by the process of the present invention may comprise a higher amount of powdery material with a high soluble fraction with low mechanical properties.

[0032] Without wishing to be bound by any theory, the inventors are of the opinion that this increase in mechanical properties can be explained by the granulometry of the clinker because the latter is greater than the granulometry of the powders which are meta kaolin, slag and cement of the current hydraulic binder.

[0033] The process of the invention is also more economical than the process using a current hydraulic binder. Indeed, the cost of clinker is much lower than the costs of blast furnace slag and meta kaolin.

[0034] The process of the invention is also simple to implement on an industrial scale to treat a significant quantity of powdery material with a high soluble fraction and clinker. Indeed, the implementation of the method of the invention does not require heavy investment in equipment since it can be implemented simply in already existing installations. Indeed, steps a) and b) of the method of the present invention are similar to the steps of the current method for stabilizing an incineration fume purification residue with a current hydraulic binder. Steps a) and b) therefore do not present any particular technical difficulties for those skilled in the art.

[0035] _According to another aspect, there is provided a method for purifying fumes from the incineration of waste implementing the treatment method as defined above and further comprising the following step: - bringing the incineration fumes into contact with a fume treatment material to form an incineration fume purification residue, said incineration fume purification residue then being used in step a) of the treatment method

[0036] The flue gas treatment material can be sodium bicarbonate, lime or their mixtures.

[0037] Contact with the flue gas treatment material, such as soda, sodium bicarbonate or lime, can be carried out dry or wet, preferably dry. For example, it is carried out dry in the case of sodium bicarbonate. For example, it is carried out dry or wet in the case of lime, preferably dry.

[0038] The purification method of the present invention is particularly advantageous because it makes it possible to effectively treat fumes, in particular from the incineration of waste and the residue from the purification of fumes, in particular from incineration.

[0039] According to another aspect, a mineral binder, preferably hydraulic, is provided for stabilizing powdery material with a high soluble fraction, in particular flue gas purification residue, in particular from incineration, comprising cement and clinker. The mineral binder may be chosen from a hydraulic binder or a pozzolanic binder.

[0040] Advantageously, the mineral binder, preferably hydraulic, for stabilization of the present invention: - allows to effectively stabilize a greater quantity of powdered material with a high soluble fraction than the current hydraulic binder comprising cement, meta kaolin and blast furnace slag, , - is more economical than the current hydraulic binder because the cost of clinker is much lower than the cost of meta kaolin and the cost of blast furnace slag, and - has a lower environmental impact than the current hydraulic binder because it opens up a new way of recovering clinker.

[0041] According to another aspect, there is provided a solid stabilized product obtainable by the treatment method as defined below.

[0042] Such a solid stabilized product is advantageous in that it allows long-term storage of a high proportion of powdered material with a high soluble fraction while avoiding the phenomenon of leaching of the soluble fraction. Brief description of the drawings

[0043] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which: Fig. 1

[0044] [Fig. 1] shows a simplified diagram of a waste incineration plant. Fig. 2

[0045] [Fig. 2] shows a diagram of the process of the present invention. Description of the embodiments

[0046] A method is provided for treating a powdery material with a high soluble fraction with a stabilizing mineral binder to obtain a solid stabilized product, said method comprising the following steps: a) bringing the powdery material, the stabilizing mineral binder and water into contact to obtain a mixture; and b) solidifying and stabilizing the mixture to obtain the solid stabilized product, characterized in that the stabilizing mineral binder comprises cement and clinker.

[0047] The mineral binder can be chosen from a hydraulic binder or a pozzolanic binder.

[0048] For the purposes of the present invention, the singular forms "a", "an", "the" and "the" also encompass the plural forms of the terms to which they refer, unless the content clearly indicates otherwise.

[0049] Weight and mass values are expressed in dry weight, unless otherwise stated.

[0050] For the purposes of the present invention, "powdery material with a high soluble fraction" means a material in powder form comprising at least 15% by weight of a soluble fraction relative to the total dry weight of the powdery material, in particular at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, and at most 100%, at most 95%, at most 90%, at most 85%, at most 80%, at most 75%, at most 70%. In the present application, the powdery material with a high soluble fraction may be referred to as powdery material.

[0051] The powdery material with a high soluble fraction may comprise at least 40% by weight of a soluble fraction relative to the total dry weight of the powdery material, in particular at least 50% by weight of a soluble fraction relative to the total dry weight of the powdery material.

[0052] The powdery material with a high soluble fraction may be a mixture of different powdery materials with a high soluble fraction.

[0053] During step a) of the process of the present invention, the powdery material with a high soluble fraction may be mixed with another waste, in particular a waste that must be stabilized before storage. For example, this other waste is different from the clinker of the mineral binder.

[0054] For the purposes of the present invention, "waste that must be stabilized before storage" means waste whose properties do not comply with at least one of the limits imposed by the French ministerial decree of 30 / 12 / 2002, as amended, relating to the storage of hazardous waste.

[0055] For the purposes of the present invention, “soluble fraction” designates a fraction comprising at least one soluble salt chosen from the salts of which: - the anion is chloride, sulfate, hydroxychloride and their combinations, and - the cation is sodium, potassium, calcium and their combinations.

[0056] The powdery material with a high soluble fraction may comprise at least 4% by weight relative to the total dry weight of the powdery material of a fraction comprising at least one soluble salt whose anion is sulfate, in particular at least 10%, at least 15%.

[0057] The powdery material with a high soluble fraction may comprise at least 15% by weight relative to the total dry weight of the powdery material of a fraction comprising at least one soluble salt whose anion is chloride, in particular at least 19%, at least 40%, at least 50%, at least 60%, and at most 100%, at most 95%, at most 90%, at most 85%, at most 80%, at most 75%, at most 70%.

[0058] The powdery material with a high soluble fraction may comprise at least 7% by weight relative to the total dry weight of the powdery material of a fraction comprising at least one soluble salt whose cation is potassium, in particular at least 10%.

[0059] The powdery material with a high soluble fraction may comprise at least 15% by weight relative to the total dry weight of the powdery material of a fraction comprising at least one soluble salt whose cation is sodium, in particular at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, and at most 100%, at most 95%, at most 90%, at most 85%, at most 80%, at most 75%, at most 70%.

[0060] For the purposes of the present invention, "solid stabilized product" means a solid material obtained by one or more reactions between the powdered material with a high soluble fraction, the stabilizing mineral binder and water. The mineral binder may be chosen from a hydraulic binder or a pozzolanic binder.

[0061] The cement used in the process of the present invention may be a cement classified under the name CEM I, CEM II, CEM III, CEM V or their mixtures, in particular CEM I, CEM II, CEM V or their mixtures, more particularly CEM IL

[0062] Cement classified under the name CEM i / 52.5 is an example of cement classified under the name CEM I which can be used in the process of the present invention.

[0063] Cement classified under the name CEM II / A42.5 and CEM II / A52.5 are examples of cements classified under the name CEM II which can be used in the process of the present invention.

[0064] Cement classified under the name CEM V / A is an example of cement classified under the name CEM V which can be used in the process of the present invention.

[0065] For the purposes of the present invention, "clinker" means a solid residue resulting from the incineration of waste. For example, the clinker may be household waste incineration clinker (MIDND), hazardous waste incineration clinker (MIDD) or mixtures thereof.

[0066] For the purposes of the present invention, "hazardous waste" means waste which exhibits one or more of the hazardous properties listed in Annex III to Directive 2008 / 98 / EC of the European Parliament and of the Council of 19 November 2008 on waste and repealing certain Directives.

[0067] Typically, the clinker of the stabilizing mineral binder may comprise molecules comprising iron, molecules comprising aluminum, molecules comprising calcium and molecules comprising silicon.

[0068] The chemical composition of clinker is very advantageous for stabilizing the soluble fraction of the powdered material. Indeed, without wishing to be bound by any theory, the inventors are of the opinion that molecules comprising iron, molecules comprising aluminum, molecules comprising calcium and molecules comprising silicon are involved in the reaction(s) stabilizing the soluble fraction in the solid stabilized product.

[0069] For example, the clinker of the stabilizing mineral binder may have at least one of the following three characteristics, in particular at least two of the following three characteristics, more particularly the following three characteristics: - the sum of its mass concentration of iron, expressed as Fe2C>3, and its mass concentration of aluminium, expressed as AI2O3, is greater than 8% relative to the mass of said clinker, - its mass concentration of calcium, expressed as CaO, is greater than 8% relative to the mass of said clinker, and - its mass concentration of silicon, expressed as SiO2, is greater than 10% relative to the mass of said clinker.

[0070] In particular, a household waste incineration clinker of the mineral binder may have at least one of the following three characteristics, in particular at least two of the following three characteristics, more particularly the following three characteristics: - the sum of its mass concentration of iron, expressed as Fe2C>3, and its mass concentration of aluminium, expressed as AI2O3, is greater than 12% relative to the mass of said clinker, - its mass concentration of calcium, expressed as CaO, is greater than 10% relative to the mass of said clinker, and - its mass concentration of silicon, expressed as SiOs, is greater than 15% relative to the mass of said clinker.

[0071] In particular, a hazardous waste incineration clinker of the mineral binder may have at least one of the following three characteristics, in particular at least two of the following three characteristics, more particularly the following three characteristics: - the sum of its mass concentration of iron, expressed as Fe2O3, and its mass concentration of aluminium, expressed as AI2O3, is greater than 8% relative to the mass of said clinker, - its mass concentration of calcium, expressed as CaO, is greater than 8% relative to the mass of said clinker, and - its mass concentration of silicon, expressed as SiO2, is greater than 10% relative to the mass of said clinker.

[0072] These mass concentrations can be determined by techniques known to those skilled in the art such as X-ray fluorescence spectrometry.

[0073] The clinker may also be free of sulfur, zinc, or mixtures thereof. This is advantageous because zinc and sulfur appear to be elements that interfere with the reactions stabilizing the soluble fraction in the solid stabilized product.

[0074] The clinker may have a particle size of less than 40 mm, in particular from 1 pm to 20 mm, more particularly from 7 pm to 8 mm.

[0075] Advantageously, such a particle size promotes the formation of a solid stabilized product having acceptable mechanical properties. In particular, the inventors have noted that a particle size greater than 40 mm may not allow the formation of a solid stabilized product. The particle size of the clinker can be determined by a technique known to those skilled in the art, such as sieving.

[0076] The clinker may comprise impurities having a particle size greater than 40 mm. Ferrous metals and non-ferrous metals are examples of these impurities. Thus, the method may comprise, before step a), a step a1) of preparing the clinker to obtain a treated clinker having a particle size less than 40 mm, in particular from 1 μm to 20 mm, more particularly from 7 μm to 8 mm, this treated clinker then being used in step a) of contacting.

[0077] The powdery material with a high soluble fraction may be a flue gas cleaning residue, said residue being obtained by treating the flue gas with a treatment material. Contacting may be carried out dry or under wet conditions.

[0078] The flue gas treatment material may be sodium bicarbonate, lime, or mixtures thereof. Preferably, contact is carried out with dry sodium bicarbonate.

[0079] The powdery material with a high soluble fraction may be a flue gas purification residue, said residue being obtained by treating the flue gas with a treatment material.

[0080] For the purposes of the present invention, “flue gas purification residue” may be a material: - obtained by treating the flue gases with a flue gas treatment material, such as sodium bicarbonate or lime, in particular sodium bicarbonate, and - comprising at least 15% by weight of a soluble fraction relative to the total dry weight of the flue gas purification residue, in particular at least 20% by weight of a soluble fraction relative to the total dry weight of the flue gas purification residue.

[0081] The powdery material with a high soluble fraction may be a residue from the purification of incineration fumes. Said residue may be obtained by treating incineration fumes with a treatment material.

[0082] For the purposes of the present invention, “incineration fume purification residue” may be a material: - obtained by treating incineration fumes with a fume treatment material, such as sodium bicarbonate or lime, in particular sodium bicarbonate, and - comprising at least 40% by weight of a soluble fraction relative to the total dry weight of the incineration fume purification residue, in particular at least 50% by weight of a soluble fraction relative to the total dry weight of the incineration fume purification residue.

[0083] Preferably, contact with the flue gas treatment material, such as soda, sodium bicarbonate or lime, is carried out dry or in wet conditions, preferably dry. For example, it is carried out dry in the case of sodium bicarbonate. For example, it is carried out dry or in wet conditions in the case of lime, preferably dry.

[0084] In this application, the residue from the purification of fumes, in particular from incineration, may be referred to as purification residue.

[0085] The composition of the purification residue obtained by treatment with sodium bicarbonate differs from the composition of the purification residue obtained by treatment with lime.

[0086] Especially : - the weight content of the soluble fraction in the purification residue obtained by treatment with sodium bicarbonate is greater than the weight content of the soluble fraction in the purification residue obtained by treatment with lime, - the weight content of NaCI in the purification residue obtained by treatment with sodium bicarbonate is greater than 40% while the weight content of NaCI in the purification residue obtained by treatment with lime is less than 40%, - the purification residue obtained by treatment with sodium bicarbonate contains K3Na(SCU)2 while the purification residue obtained by treatment with lime does not contain it, and - the purification residue obtained by lime treatment contains CaCI(OH) while the purification residue obtained by sodium bicarbonate treatment does not contain it.

[0087] For example, the soluble fraction may comprise a salt selected from NaCI, KOI, Na2SC, K3Na(SC)2, CaCI(OH) and mixtures thereof, in particular a mixture of NaCI and KOI, a mixture of NaCI and Na2SC, a mixture of NaCI and K3Na(SO4)2, a mixture of NaCI and CaCI(OH), a mixture of KCI and K3Na(SO4)2, a mixture of KCI and CaCI(OH), a mixture of Na2SO4 and KsNa(SO4)2 and mixtures thereof, in particular a mixture of NaCI, Na2SO4 and K3Na(SO4)2, a mixture of NaCI, KCI and KsNa(SO4)2 and a mixture of NaCI, KCI and CaCI(OH), more particularly still a mixture of NaCI, Na2SO4 and KsNa(SO4)2 and a mixture of NaCI, KCI and K3Na(SO4)2.

[0088] The mixture of NaCI, Na2SO4 and KsNa(SO4)2 or the mixture of NaCI, KCI and KsNa(SO4)2 may be characteristic of a purification residue obtained by treatment with sodium bicarbonate.

[0089] The mixture of NaCI, KCI and CaCI(OH) may be characteristic of a purification residue obtained by lime treatment.

[0090] The powdery material may comprise at least 40% by weight of NaCl relative to the total dry weight of said powdery material, in particular from 45% to 75%, more particularly from 50 to 60%.

[0091] The powdery material may, for example, comprise from 1% to 50% by weight of KCI relative to the total dry weight of said powdery material, in particular from 1% to 15%, more particularly from 5% to 10%.

[0092] The powdered material may comprise from 1% to 50% by weight of Na2SO4 relative to the total dry weight of said powdered material, in particular from 1% to 15%, more particularly from 1% to 5%.

[0093] The powdered material may comprise from 1% to 50% by weight of KsNa(SO4)2 relative to the total dry weight of said powdered material, in particular from 1% to 25%, more particularly from 1% to 20%.

[0094] The powdered material may comprise from 1% to 50% by weight of CaCI(OH) relative to the total dry weight of said powdered material, in particular from 30% to 45%, more particularly from 35% to 40%.

[0095] The powdery material may comprise at least 40% by weight of NaCl relative to the total dry weight of said powdery material, in particular from 45% to 75%, more particularly from 50% to 60% and, optionally: - from 1% to 50% by weight of KCI relative to the total dry weight of said powdered material, in particular from 1% to 15%, more particularly from 5 to 10%, - from 1% to 50% by weight of Na2SO4 relative to the total dry weight of said powdered material, in particular from 1% to 15%, more particularly from 1% to 5%, - from 1% to 50% by weight of KsNa(SO4)2 relative to the total dry weight of said powdered material, in particular from 1% to 25%, more particularly from 1% to 20%, or mixtures thereof.

[0096] The powdered material may include: - from 50% to 60% by weight of NaCl relative to the total dry weight of said powdered material, - from 1% to 20% by weight of K3Na(SC )2 relative to the total dry weight of said powdered material, and - from 5% to 10% by weight of KCI relative to the total dry weight of said powdered material, or from 1% to 5% by weight of Na2SC relative to the total dry weight of said powdered material.

[0097] The powdered material may include: - from 10% to 15% by weight of NaCl relative to the total dry weight of said powdered material, - from 1% to 20% by weight of KCI relative to the total dry weight of said powdered material, in particular from 5% to 15% and - from 30% to 45%, by weight of CaCI(OH), more particularly from 35% to 40%, relative to the total dry weight of said powdered material.

[0098] The sum of the weight contents of the salt(s) of the soluble fraction, relative to the total dry weight of said powdered material, cannot exceed 100%.

[0099] The powdery material may comprise from 30% to 90% by weight of the soluble fraction relative to the total dry weight of said powdery material, in particular from 35% to 80%, more particularly from 40% to 70%, more particularly still from 50% to 70%.

[0100] The soluble fraction content in the powdered material can be determined using the following protocol: - implementation of a leaching test of the powdered material according to standard NF EN 12 457-2 dated December 2002 to obtain an eluate, and - analysis of the eluate according to standard NF T 90-029 of August 2002 to determine the content of soluble fraction in the powdered material.

[0101] The content of each soluble salt present in the soluble fraction of the powdered material can be determined by this protocol and by analysis of the eluate according to standard NF EN ISO 1 1885 of November 2009 which measures the cations and anions Cl, S.

[0102] The solid stabilized product may have a soluble fraction content of from 11% to 30% relative to the total dry weight of the solid stabilized product, in particular from 12% to 28%, more particularly from 13.5% to 27%.

[0103] A portion of the soluble fraction of the solid stabilized product is leachable. Thus, the solid stabilized product may have a leachable soluble fraction content that may be less than 10% by weight relative to the total dry weight of said solid stabilized product.

[0104] Advantageously, a solid stabilized product having a leachable soluble fraction content of less than 10% by weight relative to the total dry weight of said solid stabilized product complies with the regulations for storage.

[0105] For the purposes of the present invention, "leachable soluble fraction" means the portion of the soluble fraction present in an eluate obtained by a leaching test of the solid stabilized product according to the standard NF X 31 -21 1:2012. The content of leachable soluble fraction in the solid stabilized product can be determined by analyzing the eluate according to standard NF T 90-029 of August 2002.

[0106] The maximum diameter of the volume distribution of 50% of the particles (d50) of the powdered material used in the method according to the invention may be less than or equal to 100 pm, in particular from 8 pm to 70 pm, more particularly from 25 pm to 60 pm. The d50 value can be determined by liquid laser granulometry in distilled water with a Malvern-Mastersizer 2000 laser granulometer equipped with a 120 ml “small volume” cell, the signal is processed with the Mie mathematical model.

[0107] Advantageously, a particle size in the above ranges makes it possible to increase the contact surface of the powdered material with the stabilizing mineral binder. This facilitates the homogeneous mixing of these two compounds and therefore the obtaining of the solid stabilized product. The mineral binder can be chosen from a hydraulic binder or a pozzolanic binder.

[0108] The mineral stabilizing binder may have at least one of the following three characteristics, in particular at least two of the following three characteristics, more particularly the following three characteristics: - the mass concentration of clinker is from 10% to 75%, in particular from 20% to 72%, more particularly from 40% to 70% relative to the mass of said mineral stabilizing binder, - The mass concentration of cement may be from 25% to 90%, in particular from 28% to 80%, more particularly from 30% to 60% relative to the mass of said stabilizing mineral binder, and - the mineral stabilizing binder may have a cement:clinker mass ratio of 1:0.1 to 1:4, in particular 1:0.5 to 1:3, more particularly 1:1 to 1:2.5.

[0109] Advantageously, such a mineral stabilizing binder makes it possible to effectively stabilize the soluble fraction of the solid stabilized product.

[0110] The stabilizing mineral binder may further comprise slag, ash or mixtures thereof. These compounds can participate in the effective stabilization of the soluble fraction of the solid stabilized product.

[0111] For example, the slag may be blast furnace slag, steelworks slag, or mixtures thereof, especially blast furnace slag.

[0112] The ash can be paper mill ash, step sludge ash or their mixtures.

[0113] Paper mill ash is produced by burning bark and wood chips to make paper. The ash from Step sludge is recovered from the sludge incineration furnace. Currently, paper mill ash and Step sludge ash are very little recovered. Thanks to the process of the present invention, the latter can be advantageously recovered.

[0114] Step a) can be carried out in a mixer.

[0115] The mixer is mainly used to mix and homogeneize several materials.

[0116] Step a) can be carried out at room temperature. Thus, step a) is energy efficient.

[0117] According to another aspect, there is also provided a method for purifying fumes from the incineration of waste implementing the treatment method as defined above and further comprising the following step: - bringing the incineration fumes into contact with a fume treatment material to form an incineration fume purification residue, said incineration fume purification residue then being used in step a) of the treatment process.

[0118] The flue gas treatment material can be sodium bicarbonate, lime or their mixtures.

[0119] Preferably, contact with the flue gas treatment material, such as soda, sodium bicarbonate or lime, is carried out dry or in wet conditions, preferably dry. For example, it is carried out dry in the case of sodium bicarbonate. For example, it is carried out dry or in wet conditions in the case of lime, preferably dry.

[0120] The step of bringing the incineration fumes into contact with the fume treatment material is a step well known to those skilled in the art, who will know how to implement it.

[0121] Preferably, the incineration fumes are fumes from the incineration of household waste or industrial waste.

[0122] According to another aspect, there is also provided a mineral binder, preferably hydraulic, for stabilizing powdery material with a high soluble fraction, in particular flue gas purification residue, comprising cement and clinker. The mineral binder may be chosen from a hydraulic binder or a pozzolanic binder.

[0123] According to another aspect, there is also provided a mineral binder, preferably hydraulic, for stabilizing powdery material with a high soluble fraction, in particular residue from the purification of incineration fumes, comprising cement and clinker. The mineral binder may be chosen from a hydraulic binder or a pozzolanic binder.

[0124] The mineral, preferably hydraulic, stabilizing binder of this other aspect of the invention is as described above in connection with the method of treating a powdery material with a mineral, preferably hydraulic, stabilizing binder to obtain a solid stabilized product.

[0125] Advantageously, the mineral, preferably hydraulic, stabilizing binder of this other aspect of the invention makes it possible to effectively stabilize the soluble fraction of a solid stabilized product obtained from a powdery material with a high soluble fraction such as a residue from flue gas purification, in particular from incineration. Said powdery material with a high soluble fraction is as defined below.

[0126] According to another aspect, there is provided a solid stabilized product obtainable by the treatment method as defined below.

[0127] This solid stabilized product may have a soluble fraction content of from 11% to 30% relative to the total dry weight of the solid stabilized product, in particular from 12% to 28%, more particularly from 13.5% to 27%.

[0128] For example, this solid stabilized product may comprise a leachable soluble fraction content of less than 10% by weight relative to the total dry weight of said solid stabilized product.

[0129] Advantageously, the solid stabilized product obtained by the process of the present invention therefore complies with the regulations on storage because it respects the limit of leachable soluble fraction imposed by the French ministerial decree of 30 / 12 / 2002 amended relating to the storage of hazardous waste. Example

[0130] Example 1 - Obtaining solid stabilized products

[0131] Various solid stabilized products are obtained from the following materials. - incineration flue gas purification residues with a high soluble fraction from sodium bicarbonate treatment, noted REF. They comprise between 49% and 87% by weight of leachable soluble fraction relative to their total dry weight, - a CEM II / A42.5 cement, - various bottom ash from household waste incineration, noted as Mâchefer IDND, - a hazardous waste incineration clinker, noted as IDD clinker, - fly ash. They comprise approximately 23% by weight of leachable soluble fraction relative to their total dry weight, - stationery ashes, - Step sludge ashes, and - water.

[0132] IDND slag has the following characteristics: - particle size: < 40 mm - sum of the mass concentration of iron, expressed as Fe2C>3, and the mass concentration of aluminium, expressed as AI2O3: between 20% and 22% relative to the mass of the IDND clinker, - mass concentration of calcium, expressed as CaO: between 14% and 29% relative to the mass of the IDND clinker, and - mass concentration of silicon, expressed as SiO2: between 28% and 33% relative to the mass of the IDND clinker.

[0133] The IDD Clinker has the following characteristics: - particle size: < 40 mm - sum of the mass concentration of iron, expressed as Fe2O3 and the mass concentration of aluminium, expressed as AI2O3: 9% relative to the mass of the IDD clinker, - mass concentration of calcium, expressed as CaO: 9.4% relative to the mass of the IDD clinker, and - mass concentration of silicon, expressed as SiOa: 12.8% relative to the mass of the IDD clinker.

[0134] Each solid stabilized product is obtained by the following protocol: - bringing the REF, the different materials of the hydraulic stabilization binder and the water into contact to obtain a mixture; then - solidification and stabilization of the mixture to obtain the solid stabilized product.

[0135] The formulation of the mixtures making it possible to obtain the solid stabilized products obtained by the process according to the invention is presented in Table 2.

[0136] The formulation of the mixture making it possible to obtain the solid stabilized products obtained by a process not in accordance with the invention, i.e. with a hydraulic binder without clinker, is presented in Table 3.

[0137] Example 2 - Characterization of solid stabilized products

[0138] For each mixture, at t=0 days, the content of leachable soluble fraction is determined by calculation considering that the total soluble fraction of the REF and any fly ash corresponds to the leachable soluble fraction of the mixture at t=0 days.

[0139] For each solid stabilized product, the leachable soluble fraction content is determined at 28 days as follows: - the solid stabilized product is subjected to a leaching test according to standard NF X 31 21 1:2012 to obtain an eluate, then - the eluate is analyzed according to standard NF T 90-029 of August 2002 to determine the content of leachable soluble fraction of the solid stabilized product.

[0140] The content of leachable soluble fraction in solid stabilized products obtained by a process not in accordance with the invention is also determined at 91 days by the same protocol.

[0141] Tables 2 and 3 present the results of these analyses.

[0142] As highlighted in Table 2, all the solid stabilized products obtained by the process according to the invention have a leachable soluble fraction content of less than 10% after 28 days.

[0143] They therefore comply with the storage regulations because they respect the soluble leachable fraction limit of 10% imposed by the French ministerial decree of 30 / 12 / 2002 as amended relating to the storage of hazardous waste.

[0144] Table 3 shows that the solid stabilized product comprising 12% REF has a leachable soluble fraction content greater than 10% after 28 days but less than 10% after 91 days. Thus, this solid stabilized product obtained by a process not in accordance with the invention takes three times longer as long as the solid stabilized products obtained by the process according to the invention to comply with the regulations on storage.

[0145] Table 3 also shows that the leachable soluble fraction content of the solid stabilized product comprising 30% REF is still greater than 10% after 91 days. Thus, this solid stabilized product obtained by a process not in accordance with the invention does not comply with the regulations on storage.

[0146] Furthermore, by comparing, in Tables 2 and 3, the solid stabilized products comprising 30% REF, it can be seen that the process of the present invention makes it possible to stabilize a greater quantity of powdery material with a high soluble fraction than the process not in accordance with the invention. Indeed, the solid stabilized product obtained by the process of the present invention complies with the regulations whereas the solid stabilized product obtained by the process not in accordance with the invention never complies with the regulations. 0147] [Table 2] The % are mass percentages relative to the total mass of the mixture allowing the solid stabilized product to be obtained 0148] [Table 3] The % are mass percentages relative to the total mass of the mixture allowing the solid stabilized product to be obtained.

Claims

Claims

1. A method of treating a powdery material with a high soluble fraction with a stabilizing mineral binder to obtain a solid stabilized product, said method comprising the following steps: a) bringing the powdery material, the stabilizing mineral binder and water into contact to obtain a mixture; and b) solidifying and stabilizing the mixture to obtain the solid stabilized product, characterized in that the stabilizing mineral binder comprises cement and clinker.

2. A method according to claim 1, wherein the powdery material with a high soluble fraction is a flue gas purification residue, said residue being obtained by treating the flue gas with a treatment material.

3. A method according to claim 2, wherein the flue gas treatment material is sodium bicarbonate, lime or mixtures thereof.

4. Method according to one of claims 1 to 3, in which the powdery material with a high soluble fraction is a residue from the purification of incineration fumes.

5. Method according to one of claims 1 to 4, in which, during step a), the powdery material with a high soluble fraction is mixed with another waste.

6. Method according to one of claims 1 to 5, in which the clinker of the stabilizing mineral binder is a clinker from the incineration of household waste, a clinker from the incineration of hazardous waste or their mixtures.

7. A method according to one of claims 1 to 6, wherein the clinker of the stabilizing mineral binder comprises molecules comprising iron, molecules comprising aluminum, molecules comprising calcium and molecules comprising silicon.

8. Method according to one of claims 1 to 7, in which the clinker of the mineral stabilizing binder has at least one of the following three characteristics: - the sum of its mass concentration of iron, expressed as Fe2C>3, and its mass concentration of aluminium, expressed as AI2O3, is greater than 8% relative to the mass of said clinker, - its mass concentration of calcium, expressed as CaO, is greater than 8% relative to the mass of said clinker, and - its mass concentration of silicon, expressed as SiO2, is greater than 10% relative to the mass of said clinker.

9. Method according to one of claims 1 to 8, in which the clinker has a particle size of less than 40 mm.

10. Method according to one of claims 1 to 9, in which the mineral stabilizing binder has at least one of the following three characteristics: - the mass concentration of clinker is 10% to 75% relative to the mass of said mineral stabilizing binder, - the mass concentration of cement is 25% to 90% relative to the mass of said mineral stabilizing binder, and - the cement:clinker mass ratio is 1:0, 1 to 1:

4.

11. Method according to one of claims 1 to 10, in which the mineral stabilizing binder further comprises a slag, ash or their mixtures.

12. Method according to one of claims 1 to 11 in which the powdery material with a high soluble fraction comprises at least 15% by weight relative to the total dry weight of the powdery material of a soluble fraction, preferably said soluble fraction comprising at least one soluble salt whose cation is sodium.

13. Mineral binder, preferably hydraulic, for stabilizing powdery material with a high soluble fraction comprising cement and clinker.

14. Solid stabilized product obtainable by the treatment process as defined in any one of claims 1 to 12.

15. Solid stabilized product according to claim 14 comprising a leachable soluble fraction content of less than 10% by weight relative to the total dry weight of said solid stabilized product.

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