EP2375153B1 - Processing of flue ash - Google Patents

Description

The invention relates to a method for processing fly ash from a combustion process of a waste incineration plant of domestic waste, wherein from a combustion process of domestic waste fly ash is deposited. Furthermore, the invention relates to a method for operating a waste incineration plant for household waste or the like.

In garbage incineration plants for household waste fall as solid residues Rostasche (rust and Rostdurchfall), boiler ash in the flue gas trains and filter dust in the flue gas cleaning. These residues of the combustion process contain substances that impair the usability of the residues. These are, for example, unburned carbons, soluble metals and their compounds, halogenated hydrocarbons such as eg dioxins, furans and their precursors.

For example, in the document " Reference Document On The Best Available Techniques For Waste Incineration "of the European Commission, Directorate General JRC, Joint Research Center, Institute for Technological Foresight, August 2006 , which currently documents best available techniques for waste incineration plants.

Furthermore, the treatment of waste incineration residues, for example the treatment of flash ash / incinerator slag with the best available techniques currently available, is described in the document Reference Document On The Best Available Techniques For Waste Treatment Industries ", published by the European Commission, August 2006 , described.

In addition, in DE 10 2007 057 106 A1 discloses a process for producing a compactable slag granule derived from waste incineration.

WO01 / 54800 describes a method for processing fly ash from a combustion process according to the preamble of Anspuchs. 1

In modern waste incineration plants, the waste incineration slag obtained, usually after mechanical treatment, as waste for recycling as a substitute for mineral waste, preferably used in road and road construction as antifreeze or as a base course, provided that environmental and structural requirements are met. For example, iron and non-ferrous metals, e.g. Aluminum or copper, from the waste incineration processes in steel mills or metal huts recycled.

Typically, current waste incineration processes also produce environmentally hazardous waste that is authorized for this purpose Landfills is deposited, this waste is obtained for the landfills as a mixture of fly ash and residues of waste gas purification in an amount of about 6 wt .-% to 8 wt .-% of the treated amount of waste. In this case, the amount of waste to be landfilled depends on the type of exhaust gas purification and the emission limit values for fly ash, in particular boiler dusts and filter dusts.

In addition, another important aspect of waste incineration or municipal waste incineration or the like in existing incinerators is to obtain usable energy in addition to recovering materials from the waste to improve the energy balance and also to reduce greenhouse gases , The recovery of recyclable by-products reduces (slightly) the effectiveness of recovering usable energy in thermal waste treatment.

Based on this prior art, the object of the invention is to reduce waste generated for landfills in the thermal waste utilization of household waste, it should be possible to gain an increased rate of recyclable materials.

This object is achieved by a method for processing fly ash from a combustion process of a waste incineration plant of household waste, which is separated from a combustion process of domestic waste fly ash, which is further developed by the fact that separated from the combustion process of household waste, unfractionated fly ash in a separation step metals and / or metal-containing compounds, in particular heavy metals and / or heavy metal-containing compounds, in which the fly ash is subjected to a wet chemical leaching process in the separation step, so that the fly ash is emaciated by metals and / or metal-containing compounds and / or alkaline earth metals, wherein the fly ash are treated by means of an ammoniacal leach and by means of a hydrochloric acid leaching, and then the fly ash, which is leaned around metals and / or metal-containing compounds, is metered, admixed or added to a quantity of waste to be incinerated in the combustion process, so that the mineral components of the fly ash which are depleted of metals and / or metal-containing compounds are returned to the combustion process.

The invention is based on the idea that recovered from fly ash or flue dust that are deposited in waste incineration plants or waste incineration plants in the boiler trains and filters, such as electrostatic precipitators and / or fabric filters from the combustion gas of the combustion process as boiler dusts and / or filter dusts, metals for recycling are recovered, the heavy metals are recovered in a predetermined technically pure quality and recycled to the metals or metal-containing lean compounds fly ash in the combustion process to the mineral components in the fly ash or in the boiler dusts and / or filter dusts in the from the combustion process Incorporating recovered slag, whereby an accumulation of mineral components in the waste incineration slag arises. In the recovery of heavy metals, heavy metals as carbonates (by ammoniacal leaching) or hydroxides (by low-salt leaching) in a for direct processing in corresponding metallurgical plants recovered from suitable technical purity. It also achieves a high level of recovered metals, especially heavy metals, as recyclable (by-) products.

In particular, the amount of the resulting from the combustion process or incurred by the inventive steps Landfill waste, which must be taken to appropriate landfills, well below 2.5 wt .-% of the amount of waste to be incinerated, in particular by (about) 1.5 wt .-% or more - corresponding to the mineral content of fly ash - to be incinerated Amount of waste, reduced.

The mineral constituents of the fly ash, which is or is emaciated according to the invention around heavy metals and / or heavy metal-containing compounds, contain increased proportions or fractions of silicon (Si), iron (Fe), aluminum (compared to the fly ash removed from the combustion process). Al), calcium (Ca), magnesium (Mg), sodium (Na) and / or potassium (K) and, if appropriate, sulfur (S) and / or phosphorus (Ph), the mineral constituents being present in corresponding mineral phases ).

In particular, the residues from the waste gas purification in the waste incineration plant from the exhaust gases of the combustion process contain absorbents, salts, minerals, heavy metals as well as organic components, e.g. Dioxins and / or furans or the like.

By carrying out the steps according to the invention, heavy metals in the fly ash, for example in filter dusts, are reduced and recovered for recycling, with the added addition of metals or heavy metals filter dust dusts added or metered into the combustion process by admixture in the waste or waste to be incinerated become.

In particular, domestic waste or corresponding municipal waste is incinerated in the incineration processes in waste incineration plants, for example, household waste is residual waste, organic waste, waste paper, glass, metal packaging and / or plastic packaging or lightweight packaging.

According to the invention, in the treated fly ash, in particular filter dusts and / or boiler dusts, the concentration of volatile metals, such as e.g. Arsenic, antimony, mercury, copper, lead, tin and zinc are reduced by at least 50%, preferably more than 70%, which makes it possible to reduce the heavy metals or metal-precipitated fly ash with their (increased) mineral content in the combustion process , As a result, the mineral components are incorporated into the newly formed slag of the waste incineration process, without the concentration of metals or heavy metals in the combustion gas rises to an (inadmissible) increased concentration. Thus, the concentration of metals and heavy metals does not lead to a concentration that would exceed the permissible limits. The heavy metal load of the slag is also not changed.

In a preferred embodiment of the method, it is further provided that the fly ash, which is leaned around metals and / or metal-containing compounds and in particular dehydrated, is compacted, preferably pelletized, in predetermined quantities, preferably in a pelletizer. As a result, it is possible to quantitatively solidify the fly ash obtained from the separation step in order to reduce metals and / or metal-containing compounds, in particular after a drying step, as a result of which the fly ash which is leaned against metals and / or metal-containing compounds can be handled in a simple manner and / or is added to an intermediate storage and provided for addition to the waste to be incinerated. As a result, according to the Method, a decoupling of the combustion process of the waste and the separation step or separation process with the separation or extraction of metals and / or metal-containing compounds from the fly ash or the filter dusts and / or boiler dusts possible. In particular, the pelleting or compaction of lean-to-metals fly ash in pellets or the like is particularly suitable for handling the lean ash to fly ash.

In addition, it is advantageous in the design of the method that the lean to metals and / or metal-containing compounds, compacted, preferably pelletized, fly ash is stored as fly ash residue in a buffer in pellet form, in particular, preferably stored, fly ash residue from the buffer to is added or added to burning waste. In this case, the addition or admixture of fly ash residue takes place depending on the amount of waste to be burned. Thus, it is possible, the addition or admixture of increased in their mineral shares fly ash fed the amount of waste to be burned.

Here, in the separation step, the fly ash or filter dusts and boiler dusts are subjected to a hydro-metallurgical process, which is integrated into the processing of fly ash. In the wet chemical leaching process, the, in particular unfractionated, fly ash is chemically treated in a leaching device using appropriate leaching agents, such as ammonia and acids, wherein metals and / or metal-containing compounds are washed out of the fly ash in an extraction device and separated in a further separation step.

Here, the process conditions are adapted to the chemical properties of the metals to be recovered or heavy metals accordingly. In this case, in a wet chemical process using a leaching agent slightly to moderately soluble metal-containing salts are washed out accordingly. In a wet-chemical leaching process using hydrochloric acid, the volatile heavy metals are washed out according to their solubility behavior and appropriately incorporated into a matrix for recycling.

The leaching process reduces the concentration of (volatile) heavy metals in the fly ash by at least 50%, in particular by at least 70%, whereby the fly ash is subjected to an ammoniacal leaching process and a hydrochloric acid leaching process. In one embodiment, it is also possible that the ammoniacal leaching process and the hydrochloric acid leaching process be combined to achieve a higher recovery rate of recyclable heavy metals while optimizing the consumption of leachants.

In the separation step, the heavy metals or heavy metal-containing compounds contained in the fly ash are preferably reduced by at least or more than 50%, preferably more than 70%, in their content or in their concentration by the wet-chemical leaching process. This makes it possible that the thermal waste treatment is achieved at lower emissions and a material recovery rate of the heavy metals or the heavy metal-containing compounds. In particular, it is possible that in the thermal waste treatment at low emissions in addition to iron and non-ferrous metals such as copper, aluminum, chromium steel heavy metals or heavy metal-containing compounds are recovered.

Moreover, it is advantageous in one embodiment of the method that the heavy metals or heavy metal-containing compounds contained in the fly ash are extracted after leaching with a leaching agent in an extraction step and / or, in particular after the extraction step in an extraction device, precipitated or obtained in a solvent extraction , As a result, the leaching processes and extraction processes are or are decoupled from each other. A separation of the heavy metals from the (leached fly ash) takes place in an ammoniacal leaching by a (precipitation) precipitation process and in a hydrochloric acid solution by a solvent extraction process.

For example, metals or heavy metals which form stable metal-amine complexes are dissolved in an ammoniacal leaching with ammonia (NH ₃ ), the metals, in particular heavy metals, being in an oxidic or metallic form. In this case, for example, the filter dusts from a fabric filter in a first leaching stage with a solution consisting of, for example, ammonium carbonate and ammonia water, leached, For example, cadmium, copper, nickel and zinc go into solution. As a result, alkali metals and alkaline earth metals are dissolved in addition to the aforementioned heavy metals as well.

Further, in the leaching, a residue containing water-insoluble silicate material remains. Metals which do not form metal-amine complexes, e.g. Iron, chromium or lead remain in the undissolved leaching residue. In a subsequent step, the leaching solution is separated from the remaining residue, whereby the residue is washed and freed of washing water. The resulting filtrate is then fed to the metal separation in the extraction device or stage. Moreover, in the case of hydrochloric acid leaching, it is intended to leach metals out of the filter dust, the leaching of the filter dusts being carried out in a hydrochloric acid medium, e.g. HCl (hydrochloric acid) takes place. As a result, heavy metals such as e.g. Mercury, cadmium, copper, nickel and zinc as well as lead dissolved. Subsequently, the leaching solution is separated from a remaining residue, the residue is subsequently washed and freed from the wash water. The resulting filtrate is then removed to remove e.g. Lead, cadmium, iron, copper and zinc are fed to metal recovery.

Furthermore, in a preferred development of the method, it is further provided that the residue of the leaching process, in particular mineral components, is returned to the combustion process, whereby the mineral components in the slag are further increased.

According to the invention, the fly ash in the separation step by means of an ammoniacal leaching and by means of a hydrochloric acid leaching treated. In the case of the ammoniacal leaching solution, for example, precipitation of zinc carbonates, cadmium carbonates or copper carbonates or of metal carbonates from the ammoniacal leaching solution takes place by thermal removal of the ammonia, whereby, for example, zinc is precipitated as basic zinc carbonate. In this case, the decomposition of the zinc amine complex releases ammonia again. In particular, the ammoniacal leaching is carried out using a forced circulation evaporator.

Further, in the separation of cadmium, copper, zinc and lead from the leaching solution, the organic phase (extraction reagent or solvent) is mixed intensively with a filtered aqueous phase several times, whereby the metals or heavy metals are extracted from the leaching solution. In addition, a reextraction of lead, cadmium, copper and zinc from the loaded organic phase.

In general, it can be stated that in the case of a wet-chemical treatment or wet-chemical leaching filter dust is subjected to solid / liquid separation and washing, in which case a leaching residue, preferably with mineral components, is separated off. The liquor is then filtered, the ammonia leaching evaporating the filtered leach. In the hydrochloric acid leaching the filtered liquor is extracted, whereby in a metal separation stage, the metals or heavy metals such as cadmium, lead, copper and the like are obtained as metal carbonates or metal hydroxides. Subsequently, the brine containing alkali metal chlorides contained in the metal separation may be fed to a crystallization stage to obtain alkali metal chlorides. Alternatively, the brine may also be concentrated and with other salt solutions the combustion process are removed together.

In the context of the invention, wet-chemical leaching extraction is suitable as a hydrometallurgical process for the treatment of aerial dusts. In this case, the wet chemical leaching extraction is a selective process for separation, isolation and subsequent concentration of a valuable or heavy metal or heavy metals and, for example, for volatile (heavy) metals from the flue dusts of waste incineration plants or incineration processes of household waste or the like by leaching and under Use of a (preferably organic) solvent to be recovered.

Here, in the process step of the extraction, the aqueous solution containing the recoverable (heavy) metals, mixed with an organic solvent containing a corresponding reagent. The (heavy) metal-containing recyclables react with the reagent and thus form a chemical compound that is more soluble in organic solvents than in the aqueous solution. In this way, the heavy metals are transferred as desired recyclables in the organic solution.

Subsequently, the organic solution is stripped with an aqueous solution, the solvent in this case has a composition to re-separate the chemical compound between the heavy metals as recyclables and the reagent and the heavy metals in another aqueous solution in pure form (extraction) to convict. By adjusting the liquid flows, it is possible that the concentration of heavy metals as valuable substances in the solution by a factor of 10 to 100 compared to the concentration of heavy metals in the original aqueous solution. After separation of the desired heavy metals from the organic solvent, this can be used for further extraction, wherein in an intermediate step, the organic solvent is subjected to a purification or can be.

Ammonia and hydrochloric acid are suitable as suitable leachants for wet-chemical treatment of fly ash or filter dusts, both of which are used in waste incineration plants as exhaust gas purification equipment, for example in the reduction of nitrogen oxides or in water treatment, e.g. in the regeneration of ion exchangers, be used or produced as by-products (hydrochloric acid) from the exhaust gas purification during operation of the waste incineration plant.

In the context of the invention, it is provided that as a wet chemical treatment a two-stage leaching using the combination of an ammoniacal leaching and a hydrochloric acid leaching, in order to optimally solve the relevant heavy metals for the recovery and recycling of the fly ash or from the fly ash and to reduce the consumption of resources.

Moreover, in one embodiment of the method, it is particularly advantageous that the amount to be deposited from the combustion process is reduced by (approximately) 1.5% by weight and less, corresponding to the fraction of mineral constituents of the fly ash, of the amount of waste to be combusted. It is possible that less than 1.5 wt .-%, preferably ≤ (less than / equal to) 1.0 wt .-%, the amount of waste to be incinerated as landfill or as the amount to be deposited from the combustion process is or is obtained.

In addition, in the method as fly ash, aerial dusts and / or boiler dusts from combustion gases from waste incineration processes, in particular unfractionated, are subjected to the separation step.

A further solution of the method is carried out by a method for operating a waste incineration plant for household waste or the like, wherein the method steps described above are performed. To avoid repetition, reference is expressly made to the above statements. According to the invention, a plant or device for the processing of fly ash is advantageously integrated in the waste incineration plant for household waste or the like, so that the process described above is carried out using the device for processing the fly ash.

Fig. 1

schematisch ein Prozessschema einer Müllverbrennungsanlage;

Fig. 2

schematisch eine weitere Ausführungsform eines Prozessschemas einer Müllverbrennungsanlage.

The invention will be described below without limiting the general inventive idea by means of embodiments with reference to the drawings, reference being expressly made to the drawings with respect to all in the text unspecified details of the invention. Show it:

Fig. 1

schematically a process diagram of a waste incineration plant;

Fig. 2

schematically another embodiment of a process scheme of a waste incineration plant.

In the drawings, the same or similar elements and / or parts are provided with the same reference numerals, so that of a renewed presentation is omitted in each case.

Fig. 1 schematically shows a flowchart of a waste incineration plant for the incineration of household waste or the like. In this case, collected waste 11 is introduced into a combustion chamber 12 of a combustion boiler, wherein via a discharge slag 120, in particular raw slag, is discharged.

The combustion chamber 12, in which the waste 11 or household waste, is burned, can be designed as a steam generator, wherein the steam generator is designed as mehrzügiger boiler. Furthermore, boiler dust 124 is removed from the combustion chamber 12 via another discharge. Preferably, the boiler dusts 124 are deposited at temperatures> 300 ° C, since at these temperatures (> 300 ° C), the heavy metals or their compounds are hardly or not condensed. Preferably, 50% and more of the total amount of flue dust is separated at temperatures above 300 ° C.

The waste gases produced during the combustion of waste in the combustion chamber 12 are supplied via a further discharge to a filter device 13, wherein in one embodiment the filter device 13 is designed as a fabric filter. Optionally, activated carbon is added to the exhaust gas after it leaves the combustion chamber 12 or is injected in order to absorb dioxins or furans and heavy metals. The activated coke is fed directly or is deposited on a downstream filter device 17 from the exhaust gas and added by the filter device 17 before entering the exiting the combustion chamber 12 exhaust gas in the (first) filter device 13.

The dusts in the exhaust gas are filtered by means of the fabric filter of the filter device 13 separated and discharged as flue dust 131 from the filter device 13. Subsequently, the exhaust gas from the filter device 13 via a heat exchanger 14 in an HCl scrubber (hydrochloric acid scrubber) 15 is introduced, so that in the inventive multi-stage or two-stage scrubber acidic exhaust gas components are separated from the exhaust gas. In particular, hydrochloric acid components 150 are deposited in the HCl scrubber 15, the separated hydrochloric acid 150 or its constituents being processed in a hydrochloric acid rectification device 151. For the separation of hydrochloric acid 150 from the exhaust gas, the HCl scrubber 15 water 21 is supplied.

The hydrochloric acid 150 is treated in the hydrochloric acid rectification device 151, with mixed salts and hydrochloric acid being discharged from the rectification device 151. In this case, it is possible for the crude hydrochloric acid to be concentrated to technically pure hydrochloric acid 153 in the hydrochloric acid rectification device 151. The residues 152 obtained in the hydrochloric acid rectification device 151 can be concentrated in a mixed salt preparation to a transportable solution and also evaporated to deposit them.

The deaerated in the HCl scrubber 15 exhaust gas is then fed to a sulfur dioxide scrubber 16 (SO ₂ scrubber), wherein in the sulfur dioxide scrubber 16 by the supply of lime 31 or quicklime as an absorbent from the sulfur dioxide and the lime a gypsum-containing suspension 160 is produced, which is deposited via a discharge and is supplied to a gypsum preparation device 161, so that gypsum is produced as the product of the gypsum preparation device 161. The water obtained in the gypsum preparation in the gypsum preparation device 161 is added to the water 21 provided for the HCl scrubber 15.

In addition, the purified, i. deacidified, and cleaned of sulfur compounds exhaust gas from the sulfur dioxide scrubber 16 passed over the heat exchanger 14 and guided to a further filter device 17, wherein the filter device 17 comprises a fabric filter. Activated coke 41 or hearth furnace coke (HOK) is metered into the exhaust gas before it enters the filter device 17, whereby residues of heavy metals and dioxins or furans are bound. Subsequently, a suction 18 promotes the exhaust gases to a chimney 19, so that the cleaned in the waste incinerator exhaust gases are emitted through the chimney 19 into the environment.

How out Fig. 1 Furthermore, the slag 120 discharged from the combustion chamber 12 or steam generator is fed to a, in particular mechanical, slag processing device 121, so that metals 122 and treated slag 123 are made available from the slag processing device 121. Metals 122 include both iron and non-ferrous metals. The processed slag 123 is provided as a mineral mixture for further processing and recycling.

In the context of the invention, it is possible that the slag processing device 121 is also formed externally and thus separated from the incineration and processing operations of the waste incineration plant and is operated externally.

Moreover, within the scope of the invention, it is also possible for the treated slag 123 to be subjected to slag washing and to glass separation so that glass components for recycling are made available from the processed slag become. Furthermore, within the scope of the invention, it is also possible for sludges, which have also been dried, to be recovered from the processed slag 123 for recycling.

The filter dust 130 recovered or separated from the filter device 13 is supplied to a leaching device 131, so that heavy metals are separated from the filter dust 130 in the leaching device 131, the leaching device 131 comprising the metals and metal-containing Components are fed to a metal extraction device 132, while the leached to metals and / or heavy metals, leached filter dust a pelletizer 133 is supplied.

In addition, boiler dusts 121 are supplied to the pelletizing device 133 from the combustion chamber 12 or the steam generator, so that after drying the filter dust in the pelletizing device 133 the filter dust and boiler dust leaned around metals or heavy metals are pelletized and conveyed to a buffer store 134 in which the pellets are conveyed from filter dust and boiler dust (between) are stored. From the buffer 134 and from the pelletizer 133 pellets, consisting of boiler dust and filter dust, the waste 11 is supplied.

In a further embodiment, it is possible that, for example, in an external slag processing with a glass separation stage of the slag of the pelletizer 133 is supplied to the airborne dusts and boiler dusts to be pelletized, in particular dried, sludge from the slag processing, so that the pellets of fines of the slag and shares the fly ash are produced.

In extractor 132, by performing stripping and precipitation operations, metal hydroxides and / or metal chlorides of, e.g. Cadmium, antimony, lead, copper, mercury, tin and zinc obtained, wherein resulting alkaline earth metals are fed to the mixed salts 152 from the rectification device 151.

In Fig. 2 Another schematic diagram of a waste incineration plant is shown schematically. In this case, the waste incineration plant has a dry or semi-dry exhaust gas purification, wherein from the combustion chamber 12, the exhaust gases are first fed to an electrostatic precipitator 23. Here, 23 activated carbon is added before the exhaust gas enters the electrostatic precipitator.

Using the electrostatic precipitator 23, filter dust 130 is deposited with mineral fractions and metallic fractions, in particular with heavy metal fractions. From the electrostatic precipitator 23, the hot exhaust gas is then added to a spray absorber 24, wherein in the spray absorber 24 lime 31 and activated carbon and water 21 are added. Here, the exiting in the spray absorber 24 flue gas is cooled, the acidic pollutants such as hydrogen chloride (HCl), hydrogen fluoride (HF) and sulfur dioxide (SO _X ) react with lime, whereby solid particulate reaction products.

Subsequently, the flue gas laden with reaction products, fly ash and activated coke and excess hydrated lime is fed to the filter device 17 with a fabric filter, whereby the residues 170 to be disposed of are deposited. Thereafter, the purified flue gas on the downstream induced draft 18 and the fireplace 19 emitted into the atmosphere.

The boiler dust 124 discharged in the combustion chamber 12 and the filter dust 130 discharged from the electrostatic precipitator 23 are supplied to the leaching device 131 as fly ash or fly ash, so that the fly ash is leached.

The metals or heavy metals contained in the fly ash are fed to the metal extraction device 132 in order to recover the corresponding metals for recycling. The further discharged products from the extraction stage 132 are fed to both the pelletizer 133 and the spray absorber 24.

Ammonia and acids are used as leaching agents in the leaching device 131, so that subsequently in the extraction process, the metals dissolved in the lye are dissolved out in the extraction device 132 and sent for recycling. The residues resulting from leaching and airborne dust or fly ash which has been reduced by metals or heavy metals are pelletized with their mineral components in the pelletizer 133, the mineral pellets being incorporated into the newly formed slag by being returned to the combustion chamber 12.

At the in Fig. 2 illustrated embodiment, the fly ash, consisting of boiler dust and filter dust is leached with hydrochloric acid and an aqueous ammonia solution, the salts from the metal extraction are added to the residues from the exhaust gas purification.

According to the invention boiler dusts are in the waste incineration plant and filter dusts of waste incinerators to treat the mineral components of the flue dusts or boiler dusts recycling through recycling in the combustion chamber 12 so that the mineral components are incorporated into the newly formed slag.

At the same time, the volatile metals in the dust and boiler dusts are recovered and recycled in suitable metal huts. In particular, in the waste incineration plants two process steps are carried out, first the fly ash or boiler dust and fly ash are leached with hydrochloric acid and with an aqueous ammonia solution to reduce the metal contents and salinity, after subsequent drying and pelletization of the mineral fractions of the fly ash or fly ash the Metered to metals dust particles fly the waste to be burnt 11 are supplied.

In addition, in the metals extractor 132, the metals from the fly-dusts are recovered from the leach by extraction steps, which also include stripping, extraction, and precipitation in embodiments. The recyclable metals obtained in the extraction device 132 are in particular arsenic (As), antimony (Sb), cadmium (Cd), copper (Cu), lead (Pb), mercury (Hg), tin (Sn) and zinc (Zn ).

In particular, in the operation of the waste incineration plant, the incidence of hazardous waste from the incineration processes is reduced by 1% to 2% by weight in proportion to the proportion of flue dusts, relative to the treated or incinerated waste, the hazardous waste from a landfill be supplied.

A further advantage of the method is that it can be integrated into existing plants that are state of the art for waste incineration plants without new residues requiring new disposal routes or species.

All mentioned features, including the drawings alone to be taken as well as individual features that are disclosed in combination with other features are considered alone and in combination as essential to the invention. Embodiments of the invention may be accomplished by individual features or a combination of several features.

LIST OF REFERENCE NUMBERS

11

waste

12

combustion chamber

13

filtering device

14

heat exchangers

15

HCl scrubber

16

Sulfur dioxide scrubber

17

filtering device

18

downdraft

19

fireplace

21

water

23

electrostatic precipitator

24

spray absorber

31

lime

41

activated coke

120

raw slag

121

Slag processing facility

122

Metals (iron / non-iron)

123

processed slag (mineral mixture)

124

boiler dust

130

filter dust

131

Laugungseinrichtung

132

extractor

133

pelletizer

134

interim storage

150

hydrochloric acid

151

rectification device

152

arrears

153

hydrochloric acid

160

sulfur dioxide

161

plaster Production

Claims (9)

1. Method for the treatment of fly ash from a combustion process in a waste incineration plant of municipal solid waste, whereby fly ash is separated from a combustion process of municipal solid waste, wherein metals and/or metal containing compounds, in particular heavy metals and/or heavy metal containing compounds, are separated from the fly ash, which is separated from the combustion process and non-fractioned, in a separation step, wherein in the separation step the fly ash is treated by a wet chemical leaching process, so that the fly ash is reduced by metals and/or metal containing compounds and/or earth alkaline metals, characterized in that the fly ash is treated is treated by means of ammonia alkaline leaching and by means of hydrochloric leaching and subsequently the fly ash reduced by the metals and/or metal containing compounds is, preferably dosed, mixed with or added to the waste to be incinerated in the waste incineration process so that the mineral parts of the fly ash, reduced by its metals and/or metals containing compounds, are returned to the combustion process.
2. Method according to claim 1, characterized in that the fly ash, reduced by its metals and/or metal containing compounds and in particular dewatered, is compacted, preferably pelleted, in predetermined quantities, preferably in a pelleting device.
3. Method according to claim 2, characterized in that the compacted fly ash, reduced by its metals and/or metal containing compounds, preferably formed into pellets, is stored in an intermediate reservoir as fly ash residue, wherein in particular the, preferably intermediately stored, fly ash residue from the intermediate reservoir is mixed with or added to the waste to be incinerated.
4. Method according to any of the claims 1 to 3, characterized in that in the separation step the concentration of the heavy metals or heavy metal containing compounds in the fly ash is reduced by at least 50%, preferably more than 70%, through the leaching process.
5. Method according to any of the claims 1 to 4, characterized in that the heavy metals or heavy metal containing compounds contained in the fly ash are extracted after the leaching step by means of a leaching solvent in an extraction step and/or, in particular after the extraction step, are precipitated or are obtained in a solvent extraction process.
6. Method according to any of the claims 1 to 5, characterized in that the, in particular mineral fractions containing, residue of the leaching process is returned to the incineration process.
7. Method according to any of the claims 1 to 6, characterized in that the amount of residues resulting from the incineration process that has to be disposed is reduced by 1.5 weight % and more of the amount of waste to be incinerated according to the mineral fractions of the fly ash.
8. Method according to any of the claims 1 to 7, characterized in that filter fly ash and/or boiler fly ash from flue gases of the waste incineration processes are subjected, preferably non-fractioned, as fly ash to the separation step.
9. Method for the operating a waste incineration plant for municipal solid waste, wherein the method steps are performed according to one of the claims 1 to 8.

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