MIXTURES OF MINERAL ADDITIVES AND A METHOD FOR TREATING WASTE IN COMBUSTION CHAMBERS

Abstract

Waste material combustion process in which a fuel with an ash content of 1.5 to 75% is provided, a mineral additive containing an aluminosilicate is added to the fuel to produce a mixture of fuel and mineral additive, the mixture of fuel and mineral additive is burned to produce ash, in which the mineral additive comes into contact with the ash which forms during combustion to induce crystallization of the ash surfaces and thus reduce ash coalescence.

Description

K2so4 Na2SO4 + Al2O3.2SiO2 + H2O and + Al2O3.2SiO2 + H2O 2KAlSiO4 + H2SO4 -> 2NaAlSiO4 +H2SO4 (7) (8) Excess aluminosilicate is sometimes added to increase its availability to capture toxic volatile metals and fluorine in flue gases. In another aspect, the mineral additive may include a mineral containing calcium or magnesium and can be added to obtain a stoichiometric ratio ranging from 10% to 150% of fluorine or chlorine available for the reactions: CaO + 2HF -» CaF2 + H2O (9) And CaO + 2HC1 -> CaCl2 + H2O (10) And MgO + 2HF MgF2 + H2O (11) And MgO + 2HC1 -> MgCl2 + H2O (12) In another aspect, the mineral additive may be injected into the furnace at a desired location. For example, in one aspect, the mineral additive may be injected with secondary or tertiary air into the furnace. In another aspect, the mineral additive is injected directly into the flue gases above the combustion zone of the furnace. In yet another aspect, the mineral additive is injected into a heat convection zone of the furnace. In yet another aspect, the mineral additive may be injected via a mineral additive through a SNCR De-NOx system with or without an ammonia or urea compound.The SNCR De-NOx system is commonly used to promote NOx reduction in flue gases by injecting an ammonia or urea compound into the furnace gases in the temperature range of 760°C to 1000°C, preferably 850°C to 950°C, using multiple injection levels (four or more). High temperatures required to achieve efficiency in SNCR De-NOx may require that the ammonia- or urea-containing compounds be injected into the upper portion of the combustion chamber. Examples of combustors designed to have the desirable high gas temperature zone are those used in the combustion of municipal solid waste and biomass. Therefore, using the SNCR De-NOx system can be an effective way to increase the effectiveness of the mineral additive in capturing volatile compounds in the flue gases by minimizing its contact with the fuel or ash. . In one aspect, the mineral additive may be injected into the furnace in the form of a powder. In another aspect, the mineral additive is injected into the furnace in the form of a slurry. In another aspect, the mineral additive is injected into the furnace in the form of an aggregated product or an agglomerated product. The mineral additive can be added to the furnace, while it represents from 0.1% to 5% of the fuel weight or from 1% to 5% of this weight. Apart from the structural arrangements and procedures indicated, the embodiments may include a number of arrangements and procedures other than those explained below. It goes without saying that both the preceding description and the description which follows are given only by way of example. DESCRIPTION OF EMBODIMENTS Reference will now be made in detail to a number of exemplary embodiments. Fuel may be burned in a furnace to produce heat and the heat produced may in turn be used to produce electricity, for example via a steam generator. Heating the fuel and / or materials (e.g. calcium carbonate) associated with a combustion process may result in the release of mineral constituents in the furnace, such as alkalis, alkaline earths, sulfur, chlorine, fluorine, oxides and metals (iron, zinc, antimony, vanadium, arsenic, cadmium, barium, lead, mercury, nickel, chromium, cobalt, copper, tin, manganese). In some embodiments, a mineral additive may be added to the furnace and heat may calcine at least partially the mineral additive such that the at least partially calcined mineral additive captures at least some of the alkali compounds and / or volatile mineral compounds within the furnace. Further, the mineral additive may contact the forming ash and act as nucleation sites on the surfaces of the ash, increasing the crystallization ability, crystalline fraction, and viscosity, resulting in more refractory ash. As a result, the mineral additive makes the ash less sticky, less deformable and less likely to undergo deposition and densification on the bare surfaces of the combustion chamber elements. Combustion can occur in a grate furnace, a grate combustor, a fluidized bed combustor, a pulverized fuel combustor, a rotary kiln, or any other furnace configured to burn waste. The fuel used in combustion may be mixed heterogeneous waste, such as, for example, municipal solid waste, biomass waste, animal waste or industrial waste. Municipal solid waste may include, for example, domestic household waste, sewage sludge, medical or hospital waste, furniture, tires, textile materials, plastics, rubber, cardboard and the like. Examples of animal waste include, for example, pieces of meat, bone fragments, bone meal, bedding, manure and other substances produced by or from animal production and processing.Biomass may include, for example, agricultural waste, forestry residues, wood waste, demolition wood, particle board, fiberboard, plywood, wooden pallets and boxes and other plant substances produced by forestry or agriculture. In another aspect, the fuel may include polluted biomass waste such as demolition wood, furniture wood, shredded banknote paper, waste fuel. Industrial waste may include, for example, industrial sludge, pulp sludge, waste paper, . old cardboard boxes, furniture, textiles, of the plastics, rubber, cardboard and tannery waste. Fuel-based wastes differ from the more homogeneous fuels commonly used in fossil-fueled power plants in several respects. Fuel-based wastes tend to have a much greater diversity in shape, size, and, in some cases, plasticity and flowability, particularly where plastic or rubber is present. The composition of fuel-based waste can also vary greatly depending on the source. Ash content can range from as low as 0.4% by weight (for plywood waste) to as high as 75% by weight (for livestock manure). This can lead to the production of a greater amount of dump ash than fly ash. In one aspect, the fuel used in the combustion may have an ash content of at least 10% such as, for example, 20% by weight, at least 30% by weight, at least 40% by weight, or greater than about 50% by weight. The relatively high ash content of residual fuels can result in several undesirable effects. For example, slag formation and / or agglomeration of ash that settles on the grate or furnace bed can occur, blocking the fuel supply and ash removal. It is necessary to maintain a regulated grate ash removal flow or fluidity of the fluidized bed in order to maintain a regular fuel supply, which ensures stable and efficient combustion and proper boiler operation and availability. In addition, ash, slag and deposits can be chemically reactive and can damage refractory wall linings and other furnace components, since large amounts of volatile substances can be released from residual fuel in the flue gases. flue, including for example sodium, potassium, sulfur, chlorine, fluorine, phosphorus and metals (for example Hg, Pb, Cd, Cr, As, Sb, Fe, Zn, V, Ba, Ni, Co, Cu, Mn, Sn) and then condense on the surfaces of the combustion chamber. Flue gases containing fluorinated compounds (e.g. HF) produced by the combustion of plastics and other synthetic materials can be particularly corrosive. In some cases, incinerating large volumes of waste may be more important than producing large amounts of energy. Legislation imposes constraints on ash disposal, flame temperatures for burning dioxins and furans, and the emission of toxic metal compounds and fine particulate matter. Ashes containing large amounts of soluble sulfates, chlorides, and toxic metal compounds must usually be landfilled (with the exception of biomass ash). According to one aspect of the invention, it may be beneficial, in some cases, to introduce the mineral additive in a manner that maximizes its contact and subsequent interaction with the ash that forms, for example, with fly ash, settling ash and slag. Such application may provide a number of benefits, such as: reduction of slagging, increased friability of the slag, minimization of the fall of large pieces of slag from the upper parts of the combustion chamber, which can cause defluidization of the bed, improved flow of fuel to the combustion chamber, improved efficiency of the combustion, easier and more efficient removal of slag and ash from the combustion chamber (from the walls, grate and / or bed), stabilization of the heat release rate, improved chemical resistance of ash in humid atmospheres and reduced leaching of toxic metals into aqueous solutions. Such an application can also improve the characteristics of settling ash and fly ash, as well as increase the settling ash to fly ash ratio, increase its quality and suitability for use in applications such as road materials, construction fillers, and create the possibility of exploring new uses.In addition to the effect on ash and combustion properties, the mineral additive added at low dosages in intimate contact with the fuel can still beneficially capture some of the volatile alkaline substances released during combustion, before coming into contact with the ash that forms, also helping to reduce the partial pressure of alkali metal chlorides and alkali metal sulfates (NaCl, KCl, Na2SO4, K2SO4) in the flue gases and thus the condensation of alkali metal salts on the heat exchanger tubes, i.e., reduce fouling. By reducing fouling, corrosion is also reduced and heat transfer in the heat exchangers is improved. This advantage can be obtained, provided that the dosage of the mineral additive is at least 10% of the stoichiometric ratio of . the alkali in the fuel available for the reactions between the mineral additives and the volatile alkali substances (1) to (8) described previously. Adding the mineral additive to the furnace in a way that maximizes contact with the ash surfaces can induce crystallization on the ash surface. Improving Ash and ash slagging generally involve a mechanism of coalescence of individual ash particles, followed by sintering. Coalescence and sintering of ash particles are highly dependent on mass transport mechanisms occurring at the ash surface. Viscous flow of molten ash particles may be the primary mass transport mechanism leading to coalescence and sintering of ash particles during ash agglomeration and slagging. Mineral additives may act as nucleation sites for crystals on molten ash surfaces. Crystallization of ash surfaces prevents viscous flow and consequently coalescence of ash particles, thereby preventing sintering. The resulting slag and agglomerated ash products have greater porosity and are more friable.The gas permeability through the forming ash is also increased, which allows for a uniform flow of air and combustion gases through the fuel and the forming ash particles, avoiding a punctual increase in gas velocity and thus preventing fine ash particles from being entrained in the flue gases. As a result, a reduction in the amount of fly ash is promoted. The ratio of settling ash to fly ash is thus increased. Relatively small amounts of well-dispersed fine particles of mineral additive may be sufficient to induce crystallization on the ash surface such as from about 0.2% to about 10% by weight based on the weight of the fuel. Thus, for example, crystallization by the mineral additive particles on the ash surface may be induced by the introduction of a large number of nucleation sites and by the local increase in the concentration of the elements AI2O3 and / or MgO and / or CaO on the ash surface. Surface crystallization induction performance can be enhanced by using clays with a unique silicate layered structure (1:1 clays). Crystallization on the ash surface reduces ash agglomeration and densification by counteracting slag formation. The resulting slag has greater porosity and is more friable, making it easier to break down the slag into smaller pieces. Large pieces of slag can be prevented from falling from the upper parts of the combustion chamber onto the fluidized bed. Settling slag and ash are also more easily removed from grate and fluidized bed boilers, so that fuel supply and ash removal from the grate and fluidized bed can be maintained.Fuel combustion is improved by two factors, a better and more regular supply of fuel to the combustion chamber and the greater porosity and permeability of the ash formed during combustion, which allows better access of oxygen to the combustion reaction of the fuel material. According to another aspect of the invention, alkali and toxic metals located on the ash surface (originating from absorption or condensation on the ash surface) can be immobilized by crystallization and fixed in 3D crystalline structures, which reduces their availability for the formation of soluble chlorides and sulfates. The settling ash thus also has improved chemical resistance in humid environments and leaching of toxic metals by aqueous solutions is reduced considerably. The characteristics and qualities of the settling ash improve its suitability for use in applications, such as road materials, construction fillers, and creates the opportunity to explore new applications that were not otherwise possible. For example, the mineral additive may be added to the waste fuel before it is introduced into the boiler. In some cases, it may be beneficial to co-process the waste fuel and the mineral additive by subjecting them to mechanical processes, such as pressing, compaction, grinding, shredding, shearing, cutting and the like, or by subjecting them to thermal processes or preheating. In another example, the mineral additive may be introduced by spraying it in the form of a suspension onto the waste fuel before it is introduced into the boiler. In another example, the mineral additive may be injected directly onto the waste fuel during its introduction into the boiler.In yet another aspect, in a fluidized bed combustion chamber, the mineral additive may be introduced through the bed material feed or refeed system directly onto the fluidized bed. In yet another example, the mineral additive may be introduced into the boiler in the form of a powder, an agglomerated product, or a suspension with the primary air. In cases where the mineral additive is added so as to maximize contact with the residual fuel and ash, the dosage of the mineral additive may be adjusted to ensure that sufficient mineral additive is provided to interact with the expected ash content produced by the fuel. For example, it may be beneficial to provide the mineral additive in an amount ranging from about 1% to about 100% by weight of the non-volatile ash content of the fuel. This may range from about 0.2% by weight of the fuel in cases where the residual fuel is wood waste to as much as 15% in cases where the residual fuel comprises sewage sludge or aged livestock manure. In some aspects, the mineral additive may include kaolin, ball clay, bauxite clay, smectite, bentonite, clay marl, marl, calcareous marl, other clays and / or aluminosilicate refractory minerals, such as halloysite, calcined clay, andalusite, kyanite, sillimanite, perlite, mica, chlorite, attapulgite or palygorskite and pyrophyllite. In some aspects, the mineral additive may include one or more of the foregoing and a second mineral, such as a calcium-based mineral or a magnesium-based mineral, such as calcium carbonate, lime carbonate, marble, chalk, dolomite, aragonite sand, seashells, coral, cement kiln powder, talc, brucite, and magnesium carbonate. In another aspect, the mineral additive may be added to the combustion zone or furnace in a manner designed to maximize the reaction of the mineral additive with flue gas constituents, while minimizing direct contact with the fuel and ash. Such an introduction method promotes reactions between mineral additive particles and volatile compounds released in the flue gas during waste combustion. In this respect, a mineral additive is introduced in such a way as to avoid contact with solid or liquid ash and with the fuel. Thus, for example, in grate boilers, the mineral additive particles can be injected into the flue gas flow after the fuel introduction zone, thus avoiding contact with the fuel and with the ash that settles in the grate. In bubbled fluidized bed boilers, the mineral particles can be injected into the flue gas flow after the fluidized bed. These injection methods are intended to direct the mineral additive particles parallel to the direction of flow of the flue gases in order to prevent projection of mineral particles onto slag and deposits at the bottom of the combustion zone. When adding the mineral additive directly into the flue gases, the following benefits can be achieved: reduction or elimination of the formation of salt deposits on the heat exchanger tubes, reduction of corrosion of the materials forming the combustion chamber due to the reduced amount of deposits and the change in the composition (having a lower content of alkalis, chlorides and sulfates) and structure of the deposits finally formed (they are more porous and are easily removed by the turbulence of the flue gases), reduction of toxic metals or other metal compounds, such as Hg, Pb, Cd, Cr, As, Sb, Fe, Zn, V, Ba, Ni, Co, Cu, Mn, Sn emissions into the ambient atmosphere, reduction of emission of fine particulate matter (aerosols smaller than 1 pm), reduction of water-soluble chlorides and sulfates in the fly ash,increasing the chemical resistance of fly ash and consequently reducing the leaching of toxic metals into aqueous media, improving the quality of fly ash for safer and less expensive landfilling, improving the quality of fly ash for use as a filler for construction materials (i.e. improved pozzolan properties for applications in cements), reducing corrosion of metal parts and refractory parts caused by alkali metal salts and by HF vapor and extended life of flue gas treatment equipment (cyclone, SCR, ESP, etc.). In addition, in the case where mineral additive particles eventually come into contact with the fly ash, all the benefits of increased suitability for , crystallization of the ash and its crystalline fraction are obtained. The fly ash obtained is then more refractory, less sticky, less deformable and less prone to undergo deposition and densification on the bare surfaces of the elements of the combustion chamber. In this aspect, mineral additive particles may be in the form of a powder or suspension to facilitate dispersion into individual mineral particles during injection into the combustion chamber to maximize the reaction rate with the flue gas compounds. Dispersion of the mineral additive into individual particles, along with maximizing the individual exposure time in the flue gas, results in an increased total reaction efficiency between the mineral additive and the volatile flue gas compounds. Dispersion of the mineral additive into individual particles can be effective in increasing the exposure of oxygen-rich mineral surfaces. These oxygen-rich mineral surfaces can then act to increase the oxidation of volatile toxic metal elements released during waste combustion, such as Pb, Hg, As, Cd, Cr, Sb, Co, Cu, Ba, Mn, Ni, V, Sn, Zn, leading to the formation of the corresponding metal oxides on the mineral surface and effectively immobilizing the metals. Furthermore, at the high temperatures operating in the heat radiation or convection zone (between 600°C and 1200°C), the oxidized metal ions formed on the mineral particle surfaces are also able to diffuse into the mineral particle and become fixed in the three-dimensional aluminosilicate mineral structure.The ability to diffuse metallic elements into mineral particles and, consequently, the fixation of metals in the aluminosilicate structure, increases with temperature and this is . why, according to one aspect of the invention, the mineral additive can be injected into a high temperature zone (between 600°C and 1200°C) of the boiler. Mineral additives with a silicate surface are also capable of reacting with HF pollutants in flue gases, which can occur during the combustion of certain plastics and synthetic polymers (fluoropolymers). HF can react with the silicate lattice structure of silicate minerals by the reaction: HF + O - Si - O - Si - -» - Si - OH + - Si - F by incorporating fluorine into its structure. Clays with a double silicate lattice structure (2:1 structure) can give a relatively high reaction rate with toxic metallic elements and fluorine. Diatomaceous earth also has a very porous silicate structure and a large specific surface area and can be added to the mineral additive mixture to increase the efficiency of the reaction with toxic metallic compounds and volatile fluorine compounds in flue gases.According to one aspect of the invention, minerals containing calcium and magnesium can also be mixed with aluminosilicate mineral additives in order to increase the reaction of the mineral additive with fluorine and chlorine, forming CaF2, CaCl2, MgF2, MgCl2, and capture volatile phosphorus compounds. Therefore, by introducing the mineral additive into the flue gases, the HF content upstream of the flue gas treatment system can be reduced, and corrosion can also be reduced. According to this aspect, the mineral additive can be added at a dosage ranging from 10% to 150% or more of the stoichiometric ratio of the alkali in the fuel available for the reactions K2O + A12O3.2SiO2 -» 2KAlSiO4 and Na2O + Al2O3.2SiO2 -» 2NaAlSiO4, or any of the preceding reactions from (1) to (8) between aluminosilicates and alkali metal compounds, such as NaCl, KC1, NaOH, KOH, Na2SO4, K2SO4 presented previously. The excess of aluminosilicate is sometimes added with a view to increasing its availability to capture toxic volatile metals in the flue gases; the content of CaCOa or any calcium and magnesium based compound ranges from 10% to 50% of the stoichiometric ratio of fluorine and chlorine in the fuel available to form CaCl2 or CaF2 or MgCl2 or MgF2. Normally, in this respect, the dosage may range from about 0.1% by weight of the fuel for wood waste, up to as high as 12% or more by weight for fuel based on sewage sludge, pulp sludge or animal waste. In this respect, it may be preferable to inject the mineral additive with the secondary or tertiary air into the boiler in the form of a powder or a suspension. Secondary and tertiary air are injected to ensure complete combustion of the gaseous organic constituents volatilized from the residual fuel during combustion with primary air. Alternatively, the mineral additive may be injected into the flue gases above the flame or fluidized bed in the radiant heat zone of the boiler in the form of a powder or a suspension. Alternatively, the mineral additive may be injected into the heat convection zone of the boiler in the form of a powder or a suspension. Alternatively, the mineral additive may be injected into the flue gases via the SNCR De-NOx system with or without a compound containing ammonia or urea. In this aspect, the mineral additive may comprise one or more of plastic clay, kaolin, or other aluminosilicate minerals or clays. In another aspect, the mineral additive may comprise a mixture of an aluminosilicate mineral and a calcium or magnesium-based mineral. In another aspect, the mineral additive may comprise a mixture of an aluminosilicate mineral and a silica mineral, for example diatomaceous earth. In some embodiments, a method for operating a furnace may include at least the steps of introducing a combustible material containing a mineral compound into a furnace, introducing a mineral additive having a moisture content of at least about 5% (e.g., a moisture content ranging from about 5% by weight, about 15% by weight) into the furnace, and removing at least a portion of the mineral additive from the furnace or its exhaust gas stream. In some embodiments, the mineral additive may comprise lump clay, e.g., hydrated clay that may be partially dried to a moisture content of from about 1 wt.% to at least about 50 wt.%. In some embodiments, embodiment, the lump clay may be partially dried to a moisture content of from about 4 wt% to about 16 wt%, e.g., from about 8 wt% to about 12 wt% (e.g., from about 10 wt%), from about 5 wt% to about 10 wt%, or from about 10 wt% to about 15 wt%. In some exemplary embodiments, the clay may include one or more lump clays, clay that has been shredded or ground, unenriched clay, kaolin, ball clay (e.g., clay that includes 20-80% kaolin, 10-35% mica, and / or 6-65% quartz), and clay from overburden or process waste from a kaolin mining operation or any aluminosilicate (e.g., clay from material above mined kaolin deposits). In some embodiments, the clay may have a BET surface area of ​​at least about 9 m2 / g, for example, at least about 10 m2 / g or at least about 15 m2 / g. In some embodiments, the mineral additive may be processed at least in part into a calcined mineral additive in a kiln. In some embodiments, the calcined mineral additive at least in part may serve to capture at least a portion of the alkali present in the kiln. In some embodiments, the mineral additive may be processed, at least in part, into a calcined mineral additive in a kiln. In some embodiments, the calcined mineral additive, at least in part, may serve to capture at least a portion of the alkali present in the kiln. In some embodiments, the mineral additive may contact ash to act as nucleation sites for crystallization of the ash surface, thereby increasing the crystallization ability, crystal fraction and viscosity thereof, eliminating viscous flow and coalescence of the ash.Sintering of ash particles is prevented or hindered by more refractory ash. Prior to introducing the mineral additive into the furnace, in some embodiments, the size of at least one of the mineral additives may be subjected to at least one physical modification process. For example, a physical modification process or processes may be used to reduce the size of the mineral additive to, for example, about 2.4 cm or less. In some embodiments, an exemplary physical modification process may reduce the size of the mineral additive to about 1.8 cm or less, for example, to about 1.2 cm or less. In some embodiments, the exemplary physical modification process may reduce the size of the mineral additive to about 0.6 cm or less (e.g., to about 0.3 cm or less). In other embodiments, the mineral additive may include agglomerated clay products having a maximum lump size of not more than about 7.6 cm, such as not more than about 5 cm or not more than about 2.5 cm. Examples of exemplary physical modification include at least one of crushing, hammering, roller crushing, drying, grinding, extrusion, triboelectric separation, liquid sorting, and pneumatic sorting. In some embodiments, inert material may be introduced into the furnace as a fluidization medium. Examples of inert material include, but are not limited to, sand, fuel residue, and / or gypsum. In some embodiments, a fine inert material may be selected to improve separation efficiency in a cyclone or cyclones, which may be associated with the furnace system. The mineral additive used in the exemplary method described herein may take various forms and may undergo various processes. For example, the mineral additive may include shredded and / or crushed clay. In some embodiments, the clay may be unenriched clay. As used herein, unenriched clay may include clay that has not been subjected to at least one process selected from dispersion, dilution, selective flocculation, ozone leaching, sorting, magnetic separation, chemical leaching, flotation, and dewatering of clay. In some embodiments, at least a portion of the clay may be kaolin, e.g., a hydrated aluminosilicate of the formula A12Si2O5(OH)4. In some embodiments, the clay may include ball clay.In some embodiments, the clay may comprise clay derived from overburden waste or from processes of a . an operation of extracting kaolin or an aluminosilicate mineral from a mine. In some embodiments, the clay may be clay from raw clay having a moisture content of at least about 15%. The clay may include, for example, montmorillonite kaolin. The mineral additive used in the exemplary methods described herein may be a combination of hydrated clays. For example, at least one hydrated clay may be selected to provide bond strength to the combination of hydrated clays. In some embodiments, at least one hydrated clay may be selected to increase the graininess of the combination of hydrated clays. In some embodiments, the mineral additive used in the exemplary methods described herein may have a measurable BET surface area. For example, the BET surface area may be at least about 5 m2 / g, for example, at least 10 m2 / g, or at least about 15 m2 / g, or at least about 25 m2 / g. The mineral additive used in the exemplary methods described herein may have a measurable particle size. Particle size and other particle size properties referred to herein, such as particle size distribution ("psd"), may be measured using a SEDIGRAPH 5100 instrument as provided by Micromeritics Corporation. Thus, for example, the size of a given particle may be expressed in terms of the diameter of a sphere of equivalent diameter that settles in the suspension, i.e., an equivalent spherical diameter or "esd." The measurable particle size can indicate the relative particle size of the mineral additive. In some embodiments, about 20% to about 90% of the mineral additive has a particle size less than about 1 μm. In some embodiments, about 20% to about 70% of the mineral additive has a particle size less than 1 μm. In some embodiments, about 35% to about 45% of the mineral additive has a particle size less than 1 μm. In some embodiments, about 30% to about 40% of the mineral additive has a particle size less than 1 μm. In some embodiments, about 40% to about 60% of the mineral additive has a particle size less than about 1 μm. In some embodiments, about 20% to about 95% of the mineral additive has a particle size less than about 2 μm. In some embodiments, about 30% to about 80% of the mineral additive has a particle size less than 2 μm. In some embodiments, about 65% to about 75% of the mineral additive has a particle size less than about 2 μm. In some embodiments, about 60% to about 70% of the mineral additive has a particle size less than about 2 μm. In some embodiments, about 70% to about 80% of the mineral additive has a particle size less than about 2 μm. The mineral additive used in the exemplary methods described herein may have a measurable washed sieve residue, e.g., a measurable 0.044 mm washed sieve retention. Thus, for example, the 0.044 mm wash sieve retention may range from about 0.2% to about 9%. In some embodiments, the +0.044 mm wash sieve retention may range from about 0.5% to about 8%. In some embodiments, the +0.044 mm wash sieve retention may range from about 0.5% to about 8%. In some embodiments embodiment, the retention at the +0.044 mm wash screen may range from about 0.5% to about 5%. In some embodiments, the retention at the +0.044 mm wash screen may range from about 0.5% to about 1.5%. In some embodiments, the retention at the +0.044 mm wash screen may range from about 4% to about 5%. In some embodiments, the retention at the +0.044 mm wash screen may range from about 1% to about 4.5%. In some embodiments, the retention at the +0.044 mm wash screen may range from about 4.5% to about 9%. In some embodiments, combustible materials containing mineral compounds may comprise calcium carbonate. In some embodiments, the calcium carbonate may be provided in the form of particulate limestone, marble, chalk, dolomite, aragonitic sand, seashells, coral, and / or mixtures thereof. In one embodiment, the material containing mineral compounds may comprise calcium carbon from a marine-derived deposit, for example, the mineral compound may comprise a residual salt of seawater. In some embodiments, combustion may occur in a furnace that is part of a fluidized bed reactor system for generating electricity, such as through a steam generator. For example, the furnace may be part of a bubbled fluidized bed reactor system. The furnace may be part of other systems for burning materials containing mineral compounds known to those skilled in the art. The exemplary methods described herein may be used in conjunction with a wide variety of fuels and / or materials containing mineral compounds. In some embodiments, the fuel may contain an alkaline material. In some embodiments, the fuel, associated with exemplary methods described herein, may comprise waste biofuel derived from, for example, biomass. Exemplary biomass sources include, but are not limited to, wood and wood chips, straw chips, peat, lignocellulose, waste biomass, such as bagasse, wheat stalks, corn stalks, oat stalks, and / or energy biomass, such as, for example, grasses of the genus Miscanthus. In some embodiments, materials containing mineral compounds may include materials selected to reduce at least one of SOx and NOx. For example, the material or materials containing the mineral compounds selected to reduce at least one of SOx or NOx may include calcium carbonate. Calcium carbonate may, for example, be sourced from the sea. In some embodiments, the material or materials may include at least one of a SOx and NOx trap. In addition to the mineral additive, in some embodiments, the solid matter particles may include at least one of SOx and NOx traps and / or an inert material. An exemplary SOx trap may include, for example, and without limitation, calcium carbonate. Exemplary inert materials may include, for example, sand, gypsum, and / or fuel residue. For the avoidance of doubt, the present invention includes everything defined in the following paragraphs. 1. Process for the combustion of waste material, characterized in that: a fuel comprising a waste material is provided, the fuel having an ash content of from 1.5 to 75%; adding to the fuel from 1% to 100% by weight based on the ash content of the fuel of a mineral additive containing an aluminosilicate to produce a mixture of fuel and mineral additive, optionally the mixture of fuel and mineral additive is ground or mixed; optionally thermal processes are applied to the mixture of fuel and mineral additive optionally the mineral additive is injected with primary air into the furnace optionally, for fluidized bed combustion chambers, the mineral additive is introduced into the bed material charge or into the recharge system where it is injected directly onto the fluidized bed and the mixture of fuel and mineral additive is burned to produce ash; wherein the mineral additive comes into contact with the ash that forms during combustion to induce crystallization of the ash surfaces and thereby reduce ash coalescence. 2. Method according to paragraph 1, characterized in that the mineral additive added to the fuel represents from 0.2% to 15% by weight of the fuel. 3. Method according to paragraph 1, characterized in that the mineral additive added to the fuel represents from 0.2% to 5% by weight of the fuel. 4. Method according to paragraph 1, characterized in that the mineral additive added to the fuel represents from 1 to 45% of the weight of the fuel. 5. Method according to paragraph 1, characterized in that 1 to 15% by weight of the mineral additive is added to the fuel based on the ash content of the fuel. 6. A method according to any one of the preceding paragraphs, characterized in that the combustion occurs in a combustion chamber selected from a grate furnace, a boiler combustion chamber, a fluidized bed combustion chamber, a pulverized fuel combustion chamber and a rotary kiln. 7. A method according to any one of the preceding paragraphs, characterized in that the aluminosilicate comprises a mineral selected from kaolin, halloysite, plastic clay, bauxite clay, calcined clay, smectile, bentonite, clayey marl, marl, calcareous marl, andalusite, kyanite, sillimanite, perlite, mica, chlorite, attapulgite or palygorskite and pyrophyllite. 8. Method according to any one of the preceding paragraphs, characterized in that the mineral additive further comprises a material chosen from a pozzolanic aluminosilicate and coal fly ash. 9. A method according to any one of the preceding paragraphs, characterized in that the mineral additive further comprises a mineral containing an alkaline earth metal, such as calcium carbonate, lime carbonate, marble, chalk, dolomite, aragonite sand, shells, coral, cement kiln powder, talc, brucite and magnesium carbonate. 10. A method according to any one of the preceding paragraphs, characterized in that the mineral additive has an average particle size (d50) smaller than 45 microns. 11. Method according to any one of the preceding paragraphs, characterized in that the fuel comprises solid urban waste. 12. A method according to any one of the preceding claims, characterized in that the fuel comprises biomass waste. 13. Method according to any one of the preceding paragraphs, characterized in that the fuel comprises animal waste. 14. Method according to any one of the preceding paragraphs, characterized in that the fuel comprises industrial waste. 15. Method according to any one of the preceding paragraphs, characterized in that the fuel has an ash content of at least 10%. 16. Method according to any one of the preceding paragraphs, characterized in that the fuel has an ash content of at least 20%. 17. A method according to any one of the preceding paragraphs, characterized in that the fuel has an ash content ranging from about 10% to about 75%, such as for example from about 15% to about 50%, from about 10% to about 35%. 18. Process for the combustion of a waste material characterized in that: a fuel comprising a waste material is procured, the fuel having an ash content of at least 1.5%; fuel is introduced into the combustion zone of a furnace and the fuel is burned to produce ash, and a mineral additive containing an aluminosilicate at a rate of 0.1% to 12% of the weight of the fuel is introduced into the furnace in a manner which promotes solid-gas reactions between the mineral additive and the volatile compounds of the gases flue, minimizing contact of the mineral additive with the fuel or with the ash, the mineral additive capturing alkalis, toxic metal compounds and / or fluorine from flue gases, thereby reducing the presence of soluble toxic metal compounds, chlorides and / or sulfates in the ash and hydrofluoric acid, alkalis and / or volatile toxic metal compounds in the flue gases. 19. Method according to paragraph 18, characterized in that the fuel has an ash content of at least 10%. 20. Method according to paragraph 18, characterized in that the fuel has an ash content of at least 20%. 21. A method according to any one of paragraphs 18 to 20, characterized in that the mineral additive further comprises a mineral containing an alkaline earth metal, such as calcium carbonate, lime carbonate, marble, chalk, dolomite, aragonite sand, seashells, coral, cement kiln powder, talc, brucite and magnesium carbonate. 22. A method according to any one of paragraphs 18 to 21, characterized in that the mineral additive further comprises a high surface area silicate mineral, such as a mineral containing diatomaceous earth. 23. Method according to any one of paragraphs 18 to 22, characterized in that the mineral additive is added to the furnace at a rate of 0.1% to 5% of the weight of the fuel. 24. Method according to any one of claims 18 to 23, characterized in that the mineral additive is added to the furnace at a rate of 1% to 5% of the weight of the fuel. 25. A method according to any one of paragraphs 18 to 24, characterized in that the mineral additive comprises a mineral chosen from kaolin, halloysite, plastic clay, clay marl, marl, calcareous marl, smectile, bentonite, mica, chlorite, attapulgite or palygorskite and pyrophyllite. 26. A method according to any one of paragraphs 18 to 25, characterized in that the aluminosilicate has an average particle size (d50) smaller than 45 microns. 27. Following process characterized in this solid urban. 28. Following process characterized in this biomass. 29. Following process characterized in this animals. 30. Following process characterized in this industrial. 31. Next procedure any of the fuel any of the fuel any of the fuel any of the fuel any of the paragraphs 18 to 26, includes garbage paragraphs 18 to 26, includes waste from paragraphs 18 to 26, includes waste paragraphs 18 to 26, includes waste paragraphs 18 to 30, characterized in that the aluminosilicate is added to obtain a stoichiometric ratio ranging from 10% to 150% of the alkali available in the fuel to form KAlSiO4 and NaAlSiO4 following reactions 1 to 8. 32. Process according to any one of paragraphs 18 to 31, characterized in that a mineral containing calcium or magnesium is added to obtain a stoichiometric ratio ranging from 10% to 150% of the fluorine and / or chlorine available in the reactions CaO + 2HF -> CaF2 + H2O and CaO + 2HC1 CaCl2 + H2O or MgO + 2HF -> MgF2 + H2O and MgO + 2HC1 MgCl2 + H2O. 33. Method according to any one of paragraphs 18 to 32, characterized in that the mineral additive is injected with secondary or tertiary air into the furnace. 34. A method according to any one of paragraphs 18 to 32, characterized in that the mineral additive is injected directly into the flue gases above the combustion zone of the furnace. 35. Method according to any of paragraphs 18 to 32, characterized in that the mineral additive is injected into a convection zone of the oven heat. 36. Method according to any of paragraphs 18 to 35, characterized in that the mineral additive is injected into the furnace in the form of a powder. 37. A method according to any one of paragraphs 18 to 31, characterized in that the mineral additive is added to the furnace in the form of a suspension. 38. Method according to any one of paragraphs 18 to 32, characterized in that the mineral additive is injected via a De-NOx SNCR system with or without an ammonia or urea-based compound. Examples Other embodiments of the invention will become apparent to those skilled in the art upon consideration of the description and practice of the embodiments which are described by way of example. It is believed that the description and examples are to be considered only as examples and do not limit the true scope of the invention. Example 1: Combustion of solid urban waste in a grate furnace This test is carried out using a clay containing kaolinite in a 20 Mwe kiln that burns garbage solid urban areas. The aim of the test is to demonstrate increased availability of the plant and thus energy production, as well as reduced requirements for cleaning ash deposits (using an explosive + a water hammer). The fuel used consists of solid urban waste with a fuel ash content of 28% by weight. Mineral additive is added at a dose representing 2% of the weight of solid urban waste. the mineral additive in the form of a suspension by spraying it onto the residual fuel at the entrance to the furnace just before the fuel is introduced into the conveyor leading to the grate. The addition of the mineral additive has no observable adverse effect on the steam outlet temperature (maintained at 460°C) after a three-day campaign. This result would previously have required reducing the fuel feed rate by a factor of 2. It is also observed that the use of the mineral additive reduces slagging at the grate inlet. The ash deposits appear more friable and easier to clean. The ash that settles to the bottom contains less unburned carbon, which indicates better and more complete combustion of the fuel. Example 2: Combustion of animal waste in a fluidized bed reactor This test is carried out using kaolinite-containing clay in a 16 MWth bubbled fluidized bed reactor burning animal waste. The fuel used is a mixed animal waste comprising solid waste, as well as meat and bone meal, dried bone, wood waste and liquid waste, such as blood, detergent and washing chemical effluent. The fuel ash content of the solid constituents is 22.5% by weight and that of the liquid constituents of 0.5% by weight. The ash content of the mixture is 7.4%. A kaolin-based mineral additive is added at a dose representing 6.3% of the weight of the solid fuel, or 2.5% of the total fuel mixture. The mineral additive is mixed with the fuel before introduction into the combustion chamber. It is observed that the use of the mineral additive increases the operating time of the furnace, which increases from 14 days to 37, 10 to 71 days. This makes it possible to have a much longer operating time than was previously possible for waste containing eggshells. At the end of the campaign, the fouling is easy to remove and the ash deposits are friable and easy to clean. 15 The use of the mineral additive makes it possible to increase the percentage of liquid waste. It also results in a drop in the temperature of the reactor bed (from 750°C to 700°C).

Claims

CLAIMS 1. Process for the combustion of waste material characterized in that: (HAS) a fuel comprising a waste material is provided, the fuel having an ash content of from 1.5 to 75%; adding to the fuel from 1% to 100% by weight based on the ash content of the fuel of a mineral additive containing an aluminosilicate to produce a mixture of fuel and mineral additive, optionally the mixture of fuel and mineral additive is ground or mixed; optionally thermal processes are applied to the mixture of fuel and mineral additive optionally the mineral additive is injected with primary air into the furnace optionally, for fluidized bed combustion chambers, the mineral additive is introduced into the bed material charge or into the recharge system where it is injected directly onto the fluidized bed and the mixture of fuel and mineral additive is burned to produce ash; wherein the mineral additive contacts the ash formed during combustion to induce crystallization of the ash surfaces and thereby reduce ash coalescence; and in which the fuel used in the combustion is a mixed heterogeneous waste; or (B): a fuel comprising a waste material is procured, the fuel having an ash content of at least 1.5 fuel is introduced into the combustion zone of a furnace and the fuel is burned to produce ash, and a mineral additive containing an aluminosilicate at a rate of 0.1% to 12% of the weight of the fuel is introduced into the furnace in a manner which promotes solid-gas reactions between the mineral additive and the volatile compounds of the flue gases, minimizing contact of the mineral additive with the fuel or with the ash, the mineral additive capturing alkalis, toxic metal compounds and / or fluorine from the flue gases, thereby reducing the presence of soluble toxic metal compounds, chlorides and / or sulfates in the ash and hydrofluoric acid, alkalis and / or volatile toxic metal compounds in the flue gases, and in which the fuel used in combustion is a mixed heterogeneous waste.

2. Method according to claim 1, characterized in that the mineral additive added to the fuel represents from 0.2% to 15% by weight of the fuel.

3. Method according to claim 1, characterized in that the mineral additive added to the fuel represents from 0.2% to 5% by weight of the fuel.

4. Method according to claim 1, characterized in that the mineral additive added to the fuel represents from 1 to 45% of the weight of the fuel.

5. A method according to claim 1, characterized in that 1 to 15% by weight of the mineral additive is added to the fuel based on the ash content of the fuel.

6. A method according to any one of the preceding claims, characterized in that the combustion occurs in a combustion chamber selected from a grate furnace, a boiler combustion chamber, a fluidized bed combustion chamber, a pulverized fuel combustion chamber and a rotary kiln.

7. A method according to any one of the preceding claims, characterized in that the aluminosilicate comprises a mineral selected from kaolin, halloysite, plastic clay, bauxite clay, calcined clay, smectile, bentonite, clayey marl, marl, calcareous marl, andalusite, kyanite, sillimanite, perlite, mica, chlorite, attapulgite or palygorskite and pyrophyllite.

8. A method according to any one of the preceding claims, characterized in that the mineral additive further comprises a material selected from a pozzolanic aluminosilicate and coal fly ash.

9. A method according to any one of the preceding claims characterized in that the mineral additive further comprises a mineral containing an alkaline earth metal, such as calcium carbonate, lime carbonate, marble, chalk, dolomite, aragonite sand, shells, coral, cement kiln powder, talc, brucite and magnesium carbonate.

10. A method according to any one of the preceding claims, characterized in that the fuel comprises solid urban waste.

11. A method according to any one of the preceding claims, characterized in that the fuel comprises a material chosen from biomass waste, animal waste or industrial waste.

12. A method according to any one of the preceding claims, characterized in that the fuel has an ash content ranging from about 10% to about 75%, such as for example from about 15% to about 50%, from about 10% to about 35%.

13. A method according to claim 1, characterized in that the aluminosilicate is added to obtain a stoichiometric ratio ranging from 10% to 150% of the alkali available in the fuel to form KAlSiCh and NaAlSiO4 according to the following reactions (1) to (8): K2O + Al2O3.2SiO2 2KAlSiO4 (1) Na2O + Al2O3.2SiO2 2NaAlSiO4 (2) 2KC1 + Al2O3.2SiO2 + H2O 2KAlSiO4 + 2HC1 (3) 2NaCl + Al2O3.2SiO2 + H2O 2NaAlSiO4 + 2HC1 (4) 2KOH + Al2O3.2SiO2^ 2KAlSiO4 + H2O (5) 2NaOH + Al2O3.2SiO2^ 2NaAlSiO4 + H2O (6) K2SO4 + Al2O3.2SiO2 + H2O 2KAlSiO4 + H2SO4 (7) Na2SO4 + Al2O3.2SiO2 + H2O 2NaAlSiO4 +H2SO4 (8) 14. Method according to claim 1 or 13, characterized in that a mineral containing calcium or magnesium is added to obtain a stoichiometric ratio ranging from 10% to 150% of the fluorine and / or chlorine available in the 5 reactions CaO + 2HF CaF2 + H2O and CaO + 2HC1 CaCl2 + H2O or MgO + 2HF MgF2 + H2O and MgO + 2HC1 MgCl2 + H2O.