WO2014009613A1 - Method for stabilizing and solidifying urban and/or industrial and/or marine waste - Google Patents

Description

 METHOD FOR STABILIZING AND SOLIDIFYING URBAN WASTE AND / OR

INDUSTRIAL AND / OR MARINE

Description

Technical Field of the Invention The invention relates to a method for stabilizing and solidifying an urban waste and / or industrial and / or marine comprising mixing said waste in an aqueous medium in the presence of a hydraulic binder to form a compact and stable mineral matrix encapsulating said waste. The subject of the invention is also the stabilized and solidified waste obtained by the implementation of said process as well as their use for the manufacture of a composite material of granular, mortar or concrete type.

The invention relates to the technical field of waste treatment solutions and in particular that of the recovery of waste in the sector of cementitious materials.

State of the art

Human activity generates large quantities of waste that must be managed under environmentally friendly conditions. At the same time, our company continues to draw on its natural resources by taking materials for the cementitious materials industry. The Waste recovery in the cement sector is based on the opportunity to reconcile waste management and material needs. This management method is part of a sustainable development approach and reduces human pressure on natural resources while reducing the amount of waste sent to landfills.

With the present invention, it is proposed to treat and valorize different types of polluting waste, urban and industrial, and / or marine, with a view to using them as substitute raw materials in the manufacture of composite materials of aggregates, mortars type. or concretes.

In the context of the present invention the term "urban and / or industrial waste and / or marine" means any liquid, pasty, semi-solid or solid waste having a polluting character and representing a potential risk for health or the environment and requiring appropriate treatment. By way of example of urban and / or industrial waste to be treated and recovered according to the invention, mention may be made of:

 sludges from the treatment of domestic wastewater, sludge from the treatment of industrial and / or radioactive liquid effluents, sludge resulting from the dredging and cleaning of rivers, sludge from seabed dredging works and their mixtures , to which may be added, in an extended definition, any type of toxic and / or radioactive liquid effluents, including leachates from household, industrial and / or agro-food waste storage sites.

- Fluid hydrocarbon waste, viscous or pasty, such as petroleum or carbochemical products, selected from hydrocarbons, oils, solvents, lubricants, hydraulic fluids, or mixtures thereof. dry solid waste. By way of non-limiting example, dry solid waste is derived from rubber waste, plastic waste, construction site waste, solid mineral waste, asbestos waste or asbestos cement material, residues incineration of municipal waste, wood waste or household waste, or radioactive solid waste.

We know that the new French and European regulations on the protection of the environment and public health require the stabilization and solidification of urban and industrial polluting waste with a view to rendering them inert, before they are stored in landfills or on landfills. reuse as a substitute raw material.

According to a technique well known in the prior art, the polluting waste is stabilized and solidified by mixing it with a hydraulic binder whose rehydration leads to the formation of a compact mineral matrix in which the waste is encapsulated. The main objectives of this technique are to (i) immobilize pollutant waste by trapping it in a solid mineral matrix, (ii) limit exchanges between polluting waste and the natural environment, in particular leachate water, and finally (iii) ) to improve the mechanical properties of the waste as well as their handling possibilities.

Known methods based on this technique generally give satisfaction for the encapsulation of waste in a compact mineral matrix. However, they have at least one of the following disadvantages: they use expensive hydraulic binders, such as calcium sulphate semi-hydrate alpha [EP0742784B1 (Michel LEGAL)], sulphoaluminous cement, ferroaluminous cement [WO201 1/089127 (Commissariat a l'Energie Atomique)] .

- they are expensive, in the case of discontinuous processes,

 their kinetics of development of the mechanical resistances is weak, they lead, generally, to the formation of porous mineral matrices sensitive to leaching with water,

 They are very sensitive to the low dryness of certain liquid or muddy waste,

 They are poor in salty aqueous media and / or loaded with organic and / or inorganic components.

 they do not allow treatment, in situ, immediate for example in sewage treatment plants or dredging areas.

Thus, in view of the foregoing, the object of the invention is to propose a method of stabilization and solidification of various types of urban and / or industrial and / or marine waste, which allow a sustainable absorption of the polluting elements contained in said waste. and has the lowest leaching tendency possible.

Another object of the invention is to provide such a method, which can be implemented continuously, immediately, and in good economic conditions. Another object of the invention is to improve the kinetics of development of mechanical strengths for rapid stabilization and solidification of urban and / or industrial and / or marine waste. The object of the invention is also to propose a method which makes it possible to valorize different types of urban and / or industrial and / or marine waste with a view to using them as substitute raw materials in the manufacture of a composite material of granular type, mortar or concrete.

Disclosure of the invention.

The solution proposed by the invention is a method for stabilizing and solidifying a waste, urban and / or industrial and / or marine. It consists in mixing said waste in an aqueous medium with a hydraulic binder comprising a mixture of clinker, or cement, sulfo-aluminous and anhydrite III, and whose rehydration mainly produces stable primary ettringite, so as to form a compact, stable mineral matrix encapsulating said waste. This method has the advantage of being efficient, simple to implement and inexpensive. In addition, it is a process that can be applied continuously and allows a complete and immediate recovery of waste in a usable form, for example aggregates, for the manufacture of composite materials such as concrete or mortar. Furthermore, it implements an effective hydraulic binder and less expensive than hydraulic binders known as clinkers, sulfo-aluminous cement, clinker or calcium sulphate semi-hydrate alpha. Surprisingly, it has been found that the use of a hydraulic binder comprising a mixture of clinker, or cement, sulpho-aluminous and anhydrite III, and whose rehydration mainly produces stable primary ettringite , is particularly well suited to allow:

 stabilization and solidification of different types of urban and / or industrial and / or marine waste. This waste can be liquid, pasty, semi-solid or solid.

a quasi-instantaneous triggering of the solidification of the mixture and the obtaining of a high early mechanical resistance. Indeed, in about 1 hour, the mineral matrix obtained has at least 50% of its final mechanical strength and in 24 hours at least 80% of its final mechanical strength, which is not the case of materials whose binder is consisting mainly of alpha hemihydrate calcium sulphate, blast furnace cements (CEM III), pozzolanic cements (CEM IV), clinker slag cement, calcium aluminate cement, sulpho-aluminous cement and / or any other pozzolanic composition.

 obtaining a compact, stable mineral matrix, which matrix offers very good resistance to acids, borates and sulphates and has a leachable fraction that is well below the standards required

 in-situ treatment of urban and / or industrial waste and immediate recovery and commercialization of stabilized, solidified and prepared waste in the form of aggregates, mortars or concretes.

treatment compatible with very low-level wastes such as sludge and leachates a treatment compatible with all organic or inorganic chemical compositions.

 a treatment compatible with the only water supply of the waste, including salt water.

The method according to the invention therefore has a high potential.

Other preferred features of the invention are listed below, each of these characteristics being able to be considered alone or in combination with the remarkable characteristics defined above:

^■ the weight proportion of anhydrite III hydraulic binder contained in implemented, is from 10% to 75% w / hydraulic piiant

^■ the mixture of clinker, or cement, sulfo-aluminous contained in the hydraulic binder used, is selected from group A and / or B and / or C following:

 group A: clinker yeelimite and / or, sulfo-aluminous cement yeelimite, group B: clinker, blast furnace cement, pozzolanic cement, clinker slag cement, sulfo-aluminous cement, ferro-aluminous cement, or mixtures thereof,

- group C: calcium aluminate cement.

^■ the hydraulic implemented binder further contains, in an amount less than 30% w / hydraulic smelly, quicklime, slaked lime totally or partially, or of magnesium lime.

^■ the hydraulic implemented binder further contains, in an amount less than 40% w / w ant hydraulic, hemihydrate calcium sulfate or dihydrate or anhydrite II. ^■ the hydraulic binder implemented further comprises, in an amount less than 50% w / hydraulic pi.ant, mineral fillers chosen from the following group: fly ash, limestone fillers, silica fume, metakaolin, ground slag, clinker , pozzolans, zeolites, lithium salt and the mixture of at least two of them.

^■ the hydraulic binder implemented comprises:

 10% to 75% p / hydraulic folding of anhydrite III,

 20% to 70% by weight of a component selected from the following group: clinker yeelimite, sulfo-aluminous cement yeelimite, blast furnace cement, pozzolanic cement, clinker slag cement, calcium aluminate cement, cement ferro-aluminous, quicklime, hydrated lime, magnesian lime, or mixtures thereof,

 2% to 40% by weight of calcium sulphate hemihydrate or di hydrate or anhydrite II, and

- 1% to 50% w / w hydraulic binder of mineral fillers.

^■ mixing the hydraulic binder and the waste in proportions ranging from 2% to 35% uencing hydrauiique / pdéchet, preferably in proportions ranging from

5% to 19% Hydraulic folding / pdechet-

^"Hydraulic binder mixed with the waste in the form of a slurry selected from the following group: after mud treatment of domestic sewage, sludge after treatment of industrial liquid effluents and / or radioactive mud outcome of the work of dredging and cleaning of rivers and / or seabed and their mixtures.

^■ hydraulic binder is mixed with waste in the form of a fluid slurry, a paste or slurry of a solid sludge. ^b the hydraulic binder is mixed with waste in the form of a slurry having a dryness of between 0.01% and 100%, preferably a dryness of between 15% and 35%.

the hydraulic binder is mixed with waste in the form of a sludge in the presence of a rheology modifying agent, seed seeds and cellulosic residues from fibers of plant origin, peat, waste of wood or mixtures thereof.

^■ the hydraulic binder are mixed in an aqueous medium with a cut in the form of a fluid hydrocarbon product, viscous or pasty, said fluid hydrocarbon product, viscous or pasty product is a petroleum or carbochemical, selected from hydrocarbons, oils, solvents, lubricants, hydraulic fluids, or mixtures thereof.

^" The hydraulic binder is mixed in an aqueous medium with a waste in the form of a dry solid waste derived from rubber waste, plastic waste, construction site waste, solid mineral waste, residues from asbestos-cement materials, municipal waste incineration residues, wood waste, household waste or their mixtures.

^"Mixing the hydraulic binder, in aqueous medium, with a dry solid waste implemented in the form in the form of pulverulent powder, granulate or pieces of stone, brick or rubble.

^■ mixing, in aqueous medium, the hydraulic binder with an urban waste and / or industrial and / or sea in a chamber provided with a kneader continuously or discontinuously to obtain at the outlet of the enclosure a stabilized waste, solidified and put in the form of aggregates or mortar. ^B The stabilized and solidified waste obtained in the form of aggregates at the outlet of the mixing chamber is subjected to compaction in a vibratory compacting device. Another aspect of the invention relates to the use of stabilized and solidified waste obtained by implementing the method according to the present invention, for the manufacture of a composite material of the mortar or concrete type.

Yet another aspect of the invention relates to an installation for implementing the method according to the present invention.

Other objects and advantages of the present invention will become apparent from the following description which is given for information only and which is not intended to limit its scope.

Description of the figures.

Figure 1 schematically shows an installation well suited to the implementation of the method of the invention.

Embodiments of the invention The present invention is based on the experimental observation that the use of a hydraulic binder comprising anhydrite III makes it possible to obtain a good compromise between (i) the rehydration kinetics of said binder. hydraulically mixed continuously in aqueous medium with the waste used, (ii) the kinetics of development of the mechanical strengths of the mixture, which mechanical strengths occur at the young age of the mixture (iii) the amount of stable primary ettringite present in the compact mineral mass encapsulating the waste used, which stable primary ettringite, which no longer evolves towards the secondary or delayed ettringite phase, guarantees a high level of mechanical resistance and a very low sensitivity to water leaching, (iv) the regulatory aspect and (v) the economic aspect. In the context of the present invention, the following terms mean:

^■ "stabilize": treat an urban and / or industrial and / or marine waste to give it a reduced pollutant character, in accordance with increasingly stringent environmental protection and public health regulations.

■ "solidify": treat an urban and / or industrial and / or marine waste to give it a massive solid physical structure with a primary and stable ettringitic structure, and in compliance with the durability requirements. "Aqueous medium": the water brought by the waste used. By way of non-limiting example, the water may be demineralized water, fresh water, salt water such as seawater, wastewater containing, optionally, various mineral substances and / or organic. If the waste to be stabilized and solidified contains too much or too little water, it may, prior to the implementation of the process, be subjected to any treatment known to those skilled in the art allowing, respectively of decrease or increase the amount of liquid in the waste. By way of nonlimiting examples, mention may be made of drying in particular by natural evaporation, thermal drying, drainage, centrifugation, fiiteration, dehydration, in particular on filter-press with membranes or band filter, etc. In the opposite case, one can also mention an addition of fresh water, salt water or other.

^■ "hydraulic binder comprising anhydrite III", a hydraulic binder whose components, during rehydration give as primary hydrate stable primary ettringite (more than 70% of primary ettringite in 24 hours, and can reach 90% after 72 hours), which is a mineral species, composed of calcium sulphate and hydrated aluminum, and having the formula 3CaO, Al ₂ O ₃ .3CaS0 .32H ₂ O or Ca 6 Al ₂ (SO ₄ ) ₃ (OH ) i2.26H ₂ 0. the term "stable" in relation to the primary ettringite means, in the context of the present invention, that ettringite structure is stable and no longer changes to the secondary ettringite or delayed phase.

It should be remembered that the solubility product of ettringite at equilibrium is close to 1.23 × 10 ⁴⁵ . This indicates a very low degree of solubility.

Preferably, the weight proportion of anhydrite III contained in the hydraulic binder used, ranges from 10% to 75% by hydraulic folding.

The choice of the composition of the hydraulic binder to be used in the process of the present invention depends on various and varied factors and parameters such as:

 the nature, the chemical composition, and the dryness of the waste,

- the local availability and the price of the components of the hydraulic binder to be assembled, the normative and regulatory requirements for the protection of the environment and public health, in particular the normative and regulatory requirements for certain hazardous waste, radioactive waste, heavy metals, cyanides, mercury, etc.) ■

The mixture of clinker or cement, sulfoaluminous contained in the hydraulic binder used in the process of the present invention, is preferably selected from group A and / or B and / or C following:

 group A: clinker yeelimite and / or, sulfo-aluminous cement yeelimite, - group B: clinker, blast furnace cement (CEM III), pozzolanic cement (CEM IV), clinker slag cement (CLK), sulfo-aluminous cement (CSA), ferro-aluminous cement (CFA), or their mixtures,

 group C: calcium aluminate cement. Preferably, the hydraulic binder used also contains, in an amount of less than 30% by weight, hydraulic lime, slaked lime totally or partially, or magnesium lime. The supply of lime in these different forms or phases, contributes to improving the performance of the process of the present invention. In particular, lime accelerates the process of bacteriological stabilization of the organic components contained in the waste and reduces the odor nuisance.

Even more preferably, the hydraulic binder used may further contain, in an amount of less than 40% w / w hydraulic binder calcium sulphate hemihydrate alpha or beta or dihydrate or anhydrite II. The intake of calcium sulphate semi-hydrated alpha or beta or dihydrate or anhydrite II helps to promote the majority formation of primary, stable ettringite.

The hydraulic binder used may also contain, in an amount of less than 50% by weight, mineral fillers, in particular mineral fillers of very small particle size (for example: less than 300 microns). As fine inorganic fillers that are suitable for the invention, mention may be made of fly ash, calcareous fillers, silica fumes, metakaolin, ground slags, slags, a lithium salt or a mixture of at least two between them. These mineral fillers contribute to imparting to the mineral matrices encapsulating the waste an improved mechanical resistance, especially improved mechanical resistance to young ages. They also make it possible to lower the dryness of the wastes in the form of sludge and to reduce the dosage by hydraulic binder.

The hydraulic binder used in the present invention may further contain various additives to improve the mechanical characteristics and / or to affect the rheological behavior of the mixture between the hydraulic binder and the waste to stabilize and solidify. By way of example of modifying agents, mention may be made of polycarboxylate derivatives and biosourced and / or biodegradable polymers.

According to a particularly advantageous embodiment of the invention, the hydraulic binder comprises:

- 10% to 75% w / w hydraulic binder of anhydrite III,

20% to 70% by weight of a component selected from the following group: clinker yeelimite, tallow-aluminous cement yeelimite, high cement furnace, pozzolanic cement, clinker slag cement, ferro-aluminous cement, calcium aluminate cements, quicklime, hydrated lime, magnesian lime, or mixtures thereof,

 2% to 40% by weight of calcium sulphate hemihydrate or di hydrate or anhydrite II, and

 1% to 50% p / hydraulic folding of mineral fillers.

By way of nonlimiting example of hydraulic binders suitable for implementing the method of the present invention, mention may be made of the following hydraulic binders:

 Hydraulic Binder No. 1: 65% Hydraulic Anhydrite III + 35% p / Hydraulic Clinker Hydraulic Clamp CSA (Resistances from 5 MPa to 130 MPa).

 No. 2 hydraulic binder: 60% by weight of hydraulic anhydrite III and 40% by weight of hydraulic sulfo-aluminous cement (resistance of 5 MPa to 120 MPa).

Hydraulic binder No. 3: 40% by weight of hydraulic anhydrite III, 20% by weight of hydraulic calcium sulphate hemihydrate (CaSO ₄ 1/2 H 2 O) and 40% by weight of hydraulic clinker sulfo-aluminizer CLINKER CSA 40% (Resistance from 5 MPa to 100 MPa).

 Hydraulic binder No. 4: 35% by weight of hydraulic anhydrite III, 35% by weight of hydraulic sulfo-aluminous cement and 30% by hydraulic fluid of anhydrite (resistance of 5 MPa to 98 MPa).

 No. 5 hydraulic binder: 40% by weight of hydraulic anhydrite III and 40% by weight of hydraulic cement slag sulfo-aluminous (5 MPa strength at 75 MPa).

No. 6 hydraulic binder: 50% w / w hydraulic III and 50% hydraulic pozzolanic cement (CEM IV) (resistance of 5 MPa to 70 MPa). The hydraulic binder used in the process of the invention is prepared from a mixture of clinker, or cement, sulfo-aluminous (C ₄ AsS) and dihydrated calcium sulfate (CSh), according to a process comprising the steps of:

 i) injecting into a ventilation duct, the mixture of G4A3S and CSH2 in the form of powdered powder, said duct being traversed by a turbulent flow of hot air, saturated with water vapor, having a temperature of between 250 ° C. C and 700 ° C and a speed of between 8 m / s and 40 m / s,

ii) applying a mechanical stress on the particles of the mixture of C ₄ AsS and CSH 2, so as to modify their crystalline structure,

iii) removing from said conduit, the particles of the mixture of C ₄ AsS and anhydrite III as soon as they have reached a required particle size,

iv) cooling the mixture of C ₄ AsS and anhydrite III, after step i) of aeraulic calcination.

In step i) the particles of the mixture of C ₄ AsS and CSH 2 interact chemically under the combined action:

 - saturated steam,

 thermal shock induced by the temperature of the hot air flow,

 - Mechanical shocks and homogenization of heat exchange induced by the kinetic turbulence of the air flow.

In addition to ensuring the cohesion of the hydraulic binder, these different actions act simultaneously and in synergy to cause significant stresses on the particles of C ₄ AsS and CSH 2. These constraints lead to the transformation of the crystalline mesh parameters, the new crystalline phases presenting a homogeneous and compact cement matrix. More particularly, these new very reactive phases considerably improve the rehydration kinetics of the hydraulic binders thus produced and optimize, during their rehydration, the formation of the stable primary ettringitic phases in the short term. In addition, C ₄ AsS and CShh particles undergo morphological transformations that dramatically increase their hydraulic performance, resulting in very high early and ultimate strengths of up to 100 MPa.

During the aeraulic calcination, the dehydration of CSh is controlled according to the desired performances for the hydraulic binder. The best results are obtained when the H2O content is between 0% and 5% w / pcEH2. The vaporization of the H2O molecules can advantageously cause the bursting, or even the micronization, of the CSH ₂ particles.

The mixture is thus heated in the conduit for a time varying from a few seconds to several hours. The atmosphere saturated with water vapor allows, even at temperatures of the order of 700 ° C, not to overburden the particles of C ₄ AsS and CSH 2. The flow rate of the hot air flow, its speed, its temperature, its water vapor pressure, the pressure in the duct 5 and the heating time depend on several factors, mainly the type of mixture to be treated, its flow rate. injection, the particle size of its particles, and the heating method employed. These different calcination parameters are controlled and regulated by an electronic management unit that controls the entire installation. Note:

^■ according to the cement rating: C = CaO; A = Al2O3, S = SO3; H = H2O; S

= Si0 ₂

■ C ₄ AsS and CSH 2 are the majority components of the mixture implemented in step i).

^■ It is also possible to use in step i) a mixture of C ₄ AsS and CSH2 and at least one of the following family of components: cement comprising portland cement, calcium hydroxides, iron-alumina cement, mineral fiilers (pozzolana, limestone, silica fume, marble powder), slag, lime (aerial, hydraulic, live), calcium carbonate, polycarboxylate, perlite, vermiculite, metakaolin or other chemical additives of rheology. Advantageously, the hydraulic binder is used in the process of the present invention in the form of a powder (powder) whose particle size varies from 10 microns to 120 microns.

Dihydrated calcium sulfate (CSH2), sulfo-aluminous clinker, sulfo-aluminous cement and the various components described above and which can be used in the composition of the hydraulic binder are known to those skilled in the art and are available in the trade.

Such a process for manufacturing hydraulic binders used in the context of the present invention makes it possible, on the one hand, to obtain cheap binders and, on the other hand, to reduce emissions by at least 35%. CO2 compared to traditional processes, reducing manufacturing costs by 20% to 40%. Moreover, the high performance and the high stability of these The binders have been observed up to proportions of anhydrite III ("CaSO ₄ , eH ₂ O" with e ranging from 0 to 0.05) greater than 40% in w / w hydraulic binder.

Advantageously, the waste and the hydraulic binder are mixed in proportions ranging from 10% to 35% hydraulic fluid / weight, preferably in proportions ranging from 10% to 1% by weight of hydraulic fluid. These proportions give excellent results of stabilization and solidification of the waste used and make it possible to obtain a compact mineral matrix comprising predominantly stable primary ettringite whose stability and very low solubility reduces any risk of leaching at the same time. 'water.

In a preferred variant of the process of the invention, the hydraulic binder is mixed with a waste in the form of a sludge chosen from the following group: sludge resulting from the treatment of domestic wastewater, sludge resulting from the treatment of industrial liquid effluents and / or radioactive, mud resulting from the dredging and cleaning of rivers and / or seabed and their mixtures. The water required for the rehydration of the hydraulic binder is exclusively provided by the sludge. The waste sludge implemented in the context of the present invention may contain one or more of non-toxic carbon compounds, toxic pollutants, corrosive elements, radioactive components, heavy metals and inorganic compounds. By way of non-limiting examples, these elements are chosen from the group consisting of metal hydroxides, metal oxides, carbonates, mixed nickel and potassium ferrocyanide, chlorine, fluorine, sulfur, zinc, zinc, phosphorus, mercury, lead, cadmium, arsenic, phenol, cyanides, ferrocyanides, oxalates, silicates, humic acids, strontium, ruthenium, cesium, α-emitters, such as americium, plutonium and uranium, and mixtures thereof. The composition of the sludge waste will depend not only on the origin of the initial liquid effluent but also on the treatment used to prepare a sludge from this effluent (decantation, filtration, coagulation, flocculation, coprecipitation, adsorption and other physicochemical treatments). -chemical, etc.). Sludge is defined as a suspension or dispersion of solid elements in a liquid.

The sludge waste implemented in the context of the present invention can therefore be in various forms and this, depending on the amount of liquid it contains. Thus, the waste may be liquid sludge, solid sludge, slurry mud, powdered sludge or granular sludge. Advantageously, the waste in the form of sludge used in the context of the present invention is in the form of a fluid sludge, a slurry or a solid sludge.

According to a preferred embodiment of the invention, the waste is in the form of liquid slurry, solid, pulverulent or granular, is, prior to mixing with the hydraulic binder, treated with quicklime or slaked lime for neutralize the odor nuisance and block the fermentation process. Advantageously, the waste in the form of a sludge used in the context of the present invention has a dryness of between 0.01% and 100%. The dryness of a sludge characterizing its dry matter content expressed in percentage, relative to the total mass of the sludge. It should be remembered that some leachates have a very low level of about 0.01%. In practice, the waste to be stabilized and solidified in accordance with the present invention will have a dryness of between 15% and 35%.

According to a preferred feature of the process of the invention, the hydraulic binder is mixed with a waste in the form of a sludge, in particular a fluid liquid sludge, in the presence of a rheology modifying agent, seed seeds and cellulosic residues from fibers of plant origin, peat, wood waste or mixtures thereof. This feature is interesting to allow the formulation of a product (example mortar) which adheres to the soil during its mechanical projection and which can be applied for example for the stabilization and / or the greening of soils, natural or artificial slopes or any other medium requiring stabilization and / or revegetation. By way of example of a rheology modifying agent, mention may be made of acrylic derivatives and cellulose derivatives.

In another preferred variant of the process of the invention, the hydraulic binder is mixed in aqueous medium with a waste product in the form of a fluid hydrocarbon product, viscous or pasty. Such a fluid hydrocarbon product, viscous or pasty is a petroleum or carbochemical product, selected from hydrocarbons, oils, solvents, lubricants, hydraulic fluids, or mixtures thereof. This feature is an interesting way to remove hydrocarbon products spread on a solid surface (eg oil leakage by a hydraulic compressor) or accidentally spilled into an aquatic environment (eg an oil slick on a lake or lake surface). sea). Advantageously, the fluid hydrocarbon product, viscous or pasty is, before mixing with the hydraulic binder, suspended or dispersed in fresh water or sea water. In yet another preferred embodiment of the process of the invention, is mixed in medium aqueous binding the binder with a waste in the form of a dry solid. In the process according to the invention, the origin of the waste being in solid form is not critical. By way of non-limiting example, solid waste is derived from rubber waste, plastic waste, construction site waste, solid mineral waste, asbestos waste or asbestos cement incineration of municipal waste, wood waste, household refuse or their mixtures. In practice, the particle size of the solid waste used in the process of the present invention varies from a few microns to 150 mm, preferably a few microns to 50 mm. Advantageously, the solid waste is in the form of powder, granules, or pieces of stones, bricks or rubble. In practice, the waste in the form of a solid is, before mixing with the hydraulic binder, suspended or dispersed in fresh water or seawater.

The invention will now be described with reference to the following examples and FIG. 1 given for illustrative and nonlimiting purposes.

Example 1: Installation for solidification and stabilization of a waste in the form of a sludge. As shown in FIG. 1, the installation (1) for implementing the method according to the invention comprises:

 a hopper (2) receiving the waste in the form of sludge, the hopper is fed by a conveying screw (2a) and is provided with a volumetric screw feeder bottom hopper to regulate the flow. Any other dosage means suitable for those skilled in the art may be used.

 a storage unit (3) of the hydraulic binder comprising anhydrite III and whose rehydration mainly produces stable primary ettringite. The storage unit (3) consists of one or more hoppers (3a) and (3b) in which the hydraulic binder is stored according to its composition and / or treatment chosen. The hoppers (3a) and (3b) are each equipped with a volumetric screw feeder, bottom hopper to regulate the flow. Any other dosage means suitable for those skilled in the art may be used.

 an inclined conveying screw (4) arranged below the hopper (2) so as to transport the waste discharged from the hopper (2) to the upper inlet (6a) of the cylindrical chamber (6); )

 a conveying screw (5), possibly inclined, arranged below the hoppers (3a) and (3b) so as to transport the hydraulic binder spilled by the hopper (3a) and / or (3b) via the inlets (5a) respectively. ) and (5b), to the upper inlet (6a) of the cylindrical chamber (6),

a cylindrical chamber (6) horizontal or slightly inclined provided with an upper inlet (6a) located in the vicinity of the upstream end (6d) of said enclosure (6), at least one opening (6b) located in the upper part the enclosure (6) and by which the enclosure (6) is fed with hydraulic binder, and an outlet (6c) stabilized and solidified waste, which outlet (6c) is located in the lower part and in the vicinity of the downstream end (6e) of the enclosure (6), a continuous kneader (7) of the flat kneader type provided with a single axis or a double axis and mounted longitudinally in the cylindrical chamber (6). This continuous mixer (7) kneads the mixture, allowing on the one hand, a good distribution of the waste and the binder in the mixture which becomes granular in a few minutes (1 to 3 minutes), and on the other hand, the production of aggregates which are transported as they are formed towards the exit (6th). Any other means of mixing the mixture in the enclosure, and suitable for the skilled person, may be used.

 A conveyor belt (8) (or a conveyor screw) for discharging the aggregates or mortars to a transport container (9) or a storage area.

In a preferred variant (not shown) of the installation, the conveyor belt (8) discharges the aggregates to a vibration compaction device. Such a device has the function of transforming the aggregates obtained directly (possibly without additional cement additives) into concrete blocks or any other agglomerated material. This in situ transformation of aggregates allows considerable added value. For ease of operation, the entire installation is equipped with a dashboard to centrally manage the following settings and dosages:

the hydraulic binder dosage which can vary from 100.00 Kg / m ³ to 500.00 Kg / m ³ depending on the dryness and the chemical composition of the waste being in the form of sludge or leachate.

the dosage of sludge to stabilize and solidify. the speed of rotation of the conveying screws (4) and (5) and the continuous mixer (7) which must depend on the binder dosage and the volume of sludge to be treated. The productivity of the installation according to the invention varies from:

1, 00 m ³ / hour to 120,00 m ³ / hour for the stabilization and solidification of wastes in the form of sewage sludge

10.00 m ³ / hour to 300.00 nrvWhile for the stabilization and solidification of wastes in the form of dredged sludge or river-sea sediments.

Example 2: Aggregates and mortars The waste thus stabilized and solidified, by the installation described above, are obtained in the form of aggregates whose size is between 0.5 mm and 20 mm, preferably between 1 mm and 10 mm . It is also possible to obtain aggregates in other geometric shapes, for example spherical. In general, these aggregates have a humidity ranging from 30% to 60% depending on the dryness of the sludge and dry quickly, in a period of between 24 hours and 72 hours depending on storage conditions and temperatures.

According to other embodiments (not shown) stabilized and solidified waste can also be directly obtained in the form of mortar, concrete, or vibro-compacted materials such as blocks, pavers, curbs, etc. Once dried, aggregates or mortars with excellent mechanical properties and having a leachable fraction well below the standards required, allowing them to be used as inert materials for the manufacture of new mortar or concrete type materials.

Also, the invention also relates to the use of stabilized and solidified waste obtained by the implementation of the method according to the invention for the manufacture of a composite material mortar or concrete type.

The Applicant has in fact surprisingly discovered that the stabilized and solidified waste according to the present invention, which is in the form of aggregates or mortars, is compatible with most cements having a percentage of aluminate (C3A) "(CaOHAbOs)". less than 8%. Among the cements having an aluminate percentage (C3A) of less than 8%, mention may be made, by way of non-limiting example, of blast furnace cements (CEM III), pozzolanic cements (CEM IV), clinkers, cements clinker slag, sulpho-aluminous cements, ferro-aluminous cements, calcium sulphate cements, calcium hydroxide cements or mixtures thereof.

A composite material such as concrete or mortar produced with these aggregates and containing from 50% to 80% p _gr anuiats / pmaténau composite, preferably from 60% to 70% pgranuiats / pmatériau composite, has a compressive strength ranging from 4 MPa at 130 MPa, according to tests in accordance with NF CE 196-1 standards. The method of the invention is particularly advantageous because it makes it possible to obtain various compositions of mineral matrices with a stable primary ettringic structure, by choosing the composition and the consistency of the waste to be stabilized and solidified by the hydraulic binder used in the process. present invention. It also allows the treatment of waste (eg sludge) on the site itself, which is desirable for sustainable development. Moreover, it can be carried out continuously at a temperature ranging from -5 ° C. to + 40 ° C., preferably at ambient temperature and at atmospheric pressure.

Note: The mechanical strengths indicated in the description in connection with the present invention were determined using standard 4/4/16 cm test pieces.

Claims

claims A method for stabilizing and solidifying an urban and / or industrial and / or marine waste, comprising mixing said waste in an aqueous medium with a hydraulic binder comprising a mixture of clinker, or cement, sulpho-aluminous and anhydrite and of which rehydration mainly produces stable primary ettringite, so as to form a compact, stable mineral matrix, encapsulating said waste. 2. Method according to claim 1, characterized in that the weight proportion of anhydrite III contained in the hydraulic binder used, goes from 15% to 75% w / w hydraulic binder 3. Method according to claim 1 or 2, characterized in that the mixture of clinker, or cement, sulfo-aluminous contained in the hydraulic binder used, is selected from the group A and / or B and / or C following - group A: clinker yeelimite and / or, sulfo-aluminous cement yeelimite,  group B: clinker, blast furnace cement, pozzolanic cement, clinker slag cement, sulfo-aluminous cement, ferro-aluminous cement, or mixtures thereof,  group C: calcium aluminate cement. 4. Method according to any one of the preceding claims, characterized in that the hydraulic binder used furthermore contains, in less than 30% w / w hydraulic binder, quick lime, fully or partially extinguished lime, or magnesium lime. 5. Method according to any one of the preceding claims, characterized in that the hydraulic binder used in addition contains, in an amount of less than 40% w / w hydraulic binder, calcium sulfate semi-hydrated or di hydrated or anhydrite II. 6. Method according to any one of the preceding claims, characterized in that the hydraulic binder used further comprises, in an amount of less than 50% w / w hydraulic binder, mineral fillers selected from the following group: fly ash , limestone fillers, silica fumes, metakaolin, ground slags, bottom ash, lithium salt and the mixture of at least two of them. 7. Method according to any one of the preceding claims, characterized in that the hydraulic binder used comprises:  10% to 75% w / w hydraulic binder of anhydrite III,  20% to 70% by weight of a component selected from the following group: clinker yeelimite, sulfo-aluminous cement yeelimite, blast furnace cement, pozzolanic cement, clinker slag cement, ferro-aluminous cement, bright lime, hydrated lime, magnesian lime, or mixtures thereof,  2% to 40% by weight of calcium sulphate semi hydrate or di hydrate or anhydrite II, and 1% to 50% w / w hydraulic binder of mineral fillers. 8. Method according to any one of the preceding claims, characterized in that the hydraulic binder and the urban and / or industrial waste are mixed in proportions ranging from 2% to 35% hydraulic fluid / pdechet, preferably in proportions ranging from from 5% to 19% stink hydrauiic / pdéchet 9. A method according to any one of the preceding claims, comprising mixing the hydraulic binder with a waste in the form of a slurry selected from the following group: sludge from the treatment of domestic wastewater, sludge from the treatment of industrial and / or radioactive liquid effluents, mud resulting from the dredging and cleaning of rivers and / or seabed and their mixtures. 10. A method according to any one of the preceding claims, comprising mixing the hydraulic binder with a waste in the form of a fluid sludge, a slurry or a solid sludge. A process according to any one of the preceding claims, comprising mixing the hydraulic binder with a waste in the form of a slurry having a dryness of from 0.01% to 100%, preferably a dryness of between 15% and 100% by weight. % and 35%. 12. A method according to any one of the preceding claims, comprising mixing the hydraulic binder with a waste in the form of a sludge, in the presence of a rheology modifying agent, seed seeds and cellulosic residues from fibers of vegetable origin, peat, wood waste or mixtures thereof. 13. A method according to any one of claims 1 to 8, comprising mixing in an aqueous medium, the hydraulic binder with a waste in the form of a fluid hydrocarbon product, viscous or pasty, said fluid hydrocarbon product, viscous or pasty being a petroleum or carbochemical product, selected from hydrocarbons, oils, solvents, lubricants, hydraulic fluids, or mixtures thereof. 14. A method according to any one of claims 1 to 8, comprising mixing in an aqueous medium, the hydraulic binder with a waste in the form of a dry solid from rubber waste, plastic waste, waste of construction sites, solid mineral wastes, asbestos cement residues or asbestos cement materials, municipal waste incineration residues, wood waste, household refuse or their mixtures. 15. The method of claim 14, characterized in that said dry solid waste is in the form of pulverulent powder, granulate, or pieces of stones, bricks or rubble. 16. A method according to any one of claims 1 to 15, consisting of mixing the hydraulic binder and the urban waste and / or industrial and / or marine in a chamber equipped with a mixer continuously or discontinuously to get to the output of said enclosure stabilized waste, solidified and shaped granules or mortar. 17. The method of claim 16, characterized in that it further comprises a step of subjecting the waste stabilized, solidified and obtained in the form of aggregates at the outlet of the mixing chamber, compacted in a vibratory compacting device. 18. Use of a stabilized and solidified waste obtained by the implementation of the method according to any one of claims 1 to 16 for manufacturing a composite material mortar or concrete type.