FI129938B - Method for processing ashes of municipal waste incineration and product produced by the method and use of the product - Google Patents

Abstract

The invention relates to a procedure for treating ash from the incineration of municipal waste, i.e. mixed waste. In the method according to the invention, a binder combination is formed in which fly ash, i.e. APC ash, from incineration of municipal waste, i.e. mixed waste, is mixed as an activator either in the slag that is produced as a by-product from production or in soda ash. The invention also relates to an adhesive produced by the method, to adhesive-containing materials and to their use.

Description

METHOD FOR TREATMENT OF ASH FROM THE COMBUSTION OF MUNICIPAL WASTE AND

PRODUCT FORMED BY THE METHOD AND USE OF THE PRODUCT

The object of the invention is the method defined in the introductory part of claim 1 for processing ash from incineration of municipal waste, as well as the product formed by the method defined in the introductory part of claim 7 and the use of the product defined in the introductory part of claim 13.

In the production of electricity and thermal energy, various incinerators are generally used, where the resulting ash is further processed in different ways on a case-by-case basis. Coal, wood, tree bark, peat and other biofuels, as well as natural gas, oil and increasingly also municipal waste, which can also be called mixed waste, are used as fuel in the mentioned combustion plants.

Depending on the fuel used, ash from combustion plants has to be disposed of in many different ways, for environmental reasons, among other things. When the incineration plant operates as a waste power plant, the waste is usually the aforementioned mixed waste, and in connection with the incineration of the waste, slag, boiler and fly ash, end product and APC waste are produced as side streams, which are usually harmful

N and even dangerous for people and the environment. Abbreviation APC tu-

N 25 lee from the words Air Pollution Control. In connection with this explanation, the APC waste mentioned in 3 is aviation

Q ash material or comparable material from which

The names APC ash and APC fly ash are also used below in connection with the explanation of this invention. = 30

O

O The utilization of APC ashes from waste incineration is hampered by the concentrations of substances classified as dangerous in them.

Such APC ash contains, among other things, heavy metals and salts. Therefore, APC ash from the incineration of mixed waste cannot be disposed of, for example, in landfills without separate reports.

Once the defined eligibility conditions are met, landfill placement is possible. If the eligibility conditions are not met, the mentioned APC ashes are classified as hazardous waste and must be delivered to the designated places for disposal or disposal. The final disposal of APC ash is a growing problem.

However, not all APC ash is equally dangerous as a whole, but harmful substances can be separated from it. By properly treating a large part of APC fly ash and the like, it could be used to advantage, for example, as an admixture for cement or by combining with other side streams as a binder in such a way that the solubility values do not exceed the permitted limit values. In this way, fly ash, which is difficult to dispose of, can be used safely and its disposal does not cause any problems.

Fly ash and cement can be mixed together in such a way that the end result is a binder that can be used, for example, as a building material and which is, for example, a material suitable as an earth building material or a stabilizing agent. Various slag materials are produced in the production of iron and steel

N such as stainless steel slag, stainless steel slag, sideboard slag, ma-

N 25 mouth slag and so on. In this explanation, all of these 3 slags 2 produced during the production of iron and steel will later be collectively referred to as slag. x a

Oo For example, blast furnace slag has also been used ground and mixed with cement as an earth building material, for example. In this case, ground, granulated blast furnace slag has been used together with pure cement as a binder, and the slag has been coarsely ground, in which case the D95 grain size has been over 40 µm. It has not been known how to activate slag to harden, i.e. to strengthen, other than with the help of cement, and in addition, sodium hydroxide (NaOH), i.e. most commonly lye, has had to be used as an activator. The amount of cement in the slag is approx. 20-60% by weight in binders according to known technology.

However, the problem with the known solutions is precisely the use of cement, because the manufacture of cement causes considerable C0O>2 emissions, so the development of the most environmentally friendly earth building materials and binders suitable for other uses would be desirable.

During the burning of dissolved wood in the pulp mill's cooking process, a soda precipitate is produced, which is similar in composition to wood burning ash, but is much more difficult to handle due to its wet condition. Therefore, soda ash is generally considered useless waste and its treatment is accordingly. When it gets wet, soda ash does not harden like wood ash, but softens. Soda precipitate contains a lot of lime, but also phosphorus, magnesium, manganese, sulfur and trace elements such as zinc. A lot of $S00o sludge is generated in production and large amounts of it end up in landfills, but efforts have also been made to find long-term recycling options for it.

OF

N 25 The purpose of this invention is to eliminate the above-mentioned disadvantages and to provide an inexpensive and reliable method for

Ash and other, difficult to dispose of

To process foreign substances. One of the purposes of the invention is also to provide a cement-like = 30 binder product formed by the method, in which ash from municipal waste incineration has been used as a component. Such a binder is suitable for many uses and also for earthworks. In addition, one of the purposes is to enable the maximization of the beneficial use of ash from the incineration of municipal waste, thereby expanding the possibilities for disposal of harmful ash. Another purpose of the invention is to reduce the use of cement in the binder, which can be used in construction or, for example, earthworks. In this case, the purpose is to create a binder in which little or no cement is needed.

The method according to the invention is characterized by what is presented in the characterizing part of claim 1. Correspondingly, the product manufactured by the method according to the invention is characterized by what is presented in the distinguishing mark part of claim 7, and the use of the product is characterized by what is presented in the distinguishing mark part of claim 13. Other application forms of the invention are characterized by what is presented in other patent claims.

Typically, in the method according to the invention for treating municipal waste or mixed waste incineration ash, a binder combination that partially or completely replaces cement is formed, in which municipal waste or mixed waste incineration fly ash, i.e. APC ash, is mixed with ground and/or grain size-sorted slag or soda ash to suit the purpose as a consolidating binder for various purposes, mate-

N rial, for example as earth building material or stabilization agent

N 25 for use as a neen or for use as a building material or to facilitate final disposal.

OF

E The cement-like binder combination according to the invention can comprise approx. 60-80%, preferably approx. 75% essentially harmless ground = 30 slag and approx. 20-40%, preferably approx. 25% municipal waste, i.e. mixed waste combustion fly ash, i.e. APC ash. The binder combination according to the invention can also comprise up to approx. 70-90%, preferably 75%, of fly ash from burning municipal waste, i.e. mixed waste, i.e. APC ash, and approx. 10-30%, preferably approx. 25% when burning wood dissolved in the pulp mill's cooking process. formed soda ash. 5 In the method according to the invention, slag is activated with APC ash, for example blast furnace slag and soda ash. In this case, APC ash, which comprises calcium oxide (CaO) in weight percentages of no more than approx. 70%, suitably approx. 50-65%, and preferably more than 40%, is mixed dry with powdery slag or soda ash. APC ash is mixed with the binder prepared in this way as an activator of slag and soda ash to cause a consolidation reaction of the binder mixed with water.

The binder combination according to the invention can also comprise other additives than only APC ash and slag or only APC ash and soda ash. In this case, the amount of other additives reduces the percentages mentioned above.

One of the great advantages of the solution according to the invention is the utilization of materials that are difficult to dispose of, such as municipal waste incineration ash or APC waste incineration ash, as well as the above-mentioned slag and soda ash. This is done by using substances generated as a side stream of these productions

N can replace part of the cement powder, which would otherwise be used, for example, as a binder for building materials such as concrete and earthworks. The result is the manufacture of cement

Reduction of CO> emissions caused by N, because cement is not now

E is needed as a binder. With the solution according to the invention, a very good ecological footprint is achieved, because cement does not have to be used at all, but is replaced, for example

O with the above-mentioned slag or soda ash produced in the production of iron and steel. Another advantage is that lye does not have to be used as an activator affecting the consolidation of the binder containing ground granulated slag, but with a suitable dosage, the ash-based activator

APC waste that initiates the slag solidification reaction. The hardened, i.e. strengthened, binder in this way even meets the strength requirements according to CEM III.

Due to the compounds it contains that are harmful and dangerous to people, animals and the environment, fly ash from the combustion of municipal waste, or more generally mixed waste, or APC ash, has not previously been able to be freely used for recycling purposes and also not freely disposed of anywhere. Based on the results of numerous studies and experiments carried out by the inventor, the inventor has been able to develop a new, innovative solution for utilizing APC ash in an affordable and safe way. In this solution, APC ash is mixed, preferably dry, with suitably prepared granulated and ground metal production slag, such as blast furnace slag, or alternatively with the previously mentioned, dried and suitably finely ground soda ash. In this way, a new and innovative cement-like binder is formed, suitable for the purpose of use, which can be used, for example, to fill mines, to stabilize soil to strengthen loose soil, as a construction material, asphalt construction-

For N and other suitable purposes. & 25 3 It is particularly advantageous in the invention that various harmful substances, such as APC

E ash, slag from iron and steel production and soda ash, o which are mostly still difficult to dispose of, can be 2 30 the results of the aforementioned inventor's research and experiments

In the manner developed on the basis of O, mixing with each other in a very special ratio and composition so that the resulting material, in this case a cement-like binder suitable for many purposes g, is no longer a harmful or dangerous substance. For example, even though the APC ash as a starting product contains dangerous substances that dissolve in the ground, such as chloride, when mixed in the manner according to the invention with the slag or soda precipitate treated according to the invention, the solubility values of the APC ash in the said mixture no longer exceed the permitted limit values. In this way, APC ash mixed with slag or soda ash can be used safely, for example, for soil improvement.

It can be stated that the solution according to the invention comprises the manufacture and use of a cement-like binder combination and, as a product, the binder combination itself, which binder combination comprises a certain percentage of advantageously classified and, if necessary, additionally ground and reclassified APC ash after classification, and a certain percentage of either suitably prepared ground slag or soda ash. In addition, the mentioned binder combination, i.e. binder in short, can comprise a certain percentage of one or more of the following ingredients: bark combustion fly ash, bark combustion fly ash, peat combustion fly ash, wood combustion fly ash, other bio combustion fly ash, coal combustion fly ash. In addition, said binder combination may contain various additives.

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N 25 With the method according to the invention, the mentioned powdery binder combination 3 is preferably prepared dry by mixing 2 with each other N% municipal waste, i.e. more generally mixed waste pol-

E ton fly ash, i.e. APC ash and either ground slag generated in iron and/or steel production or soda ash generated in forest industry 2 30 processes.

S

Preferably, APC ash is mixed with the binder to be prepared as an activator, which causes the binder to consolidate

that is, the hardening reaction when the binder is mixed with water.

In this case, it is not necessary to use, for example, sodium hydroxide (NaOH) as an activator. For example, the consolidation reaction of a binder containing slag already starts with approx. 20% APC ash content. Correspondingly, the consolidation reaction of a binder containing soda ash already starts with an APC ash content of less than 70%.

The aforementioned APC ash percentage N is the weight percentage and any percentage between 20-80%, suitably one at a time of the following whole numbers and their decimal parts 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 , 32, 33, 34, 35, 36, 37, 38. 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56 , 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 174, 75, 76, 77, 78, 79. In short, the weight percent number N can take any integer value with its decimal part between 20 and 80, including these values when APC ash is used alone. If APC ash is used together with another suitable admixture mixed with slag or soda ash, it can be

Less than 20% of APC ash is used.

As a result of numerous tests and experiments carried out by the inventor, it has become clear that not all ashes work equally well with the invention

For the production of a binder according to N. Depending, among other things, on the

Depending on the material to be burned and the burning temperature, the composition of the ash can be very different. Raw material for incineration of mixed waste

They vary considerably, so also the incineration of mixed waste

The composition of the APC ash obtained varies accordingly. Suitably o APC- = 30 ash used in the production of the binder according to the invention contains calcium oxide (CaO) in an amount sufficient for the purpose of use. In this case, APC ash has calcium oxide in weight percentages of no more than approx. 70%, preferably approx. 50-65% and preferably more than 40%. If there is too little calcium oxide, the mixture of APC ash and slag or APC ash and soda ash does not cause the right reaction and it does not, for example, consolidate to the strength required for its purpose.

If the ash used does not contain enough calcium oxide, other substances containing sufficient calcium oxide can be used in addition to the ash in the production of the binder. However, what is essential is the end result, i.e. the fact that the powder-like binder of the invention contains calcium oxide in weight percentages of no more than approx. 70%, preferably approx. 50-65% and preferably more than 40%.

Preferably, the ash from the incineration of APC waste used for mixing is classified by grain size and, if necessary, ground. The ash can be processed so that it is first classified, after which the coarse-grained fraction is ground and classified again. The ash D95 used in the mixture has a grain size between 10 and 40 µm, preferably between 20 and 25 µm. It is essential that the APC ash is as uniform in grain size as possible and suitable for its purpose.

During the sorting phase, enriched heavy metals and other toxins in the ash are easily

N removes by moving the sorted smaller fractions to the whole

N 25 for other use, for example hazardous waste. £ 2 Preferably also powdery soda ash used for mixing

E is pre-classified to a grain size suitable for the purpose. The grain size of the soda ash D95 suitably used for mixing is between 10-40 µm, preferably between 20-30 µm and most preferably around 25 µm. Here, too, it is essential that the soda ash is as uniform in grain size as possible and suitable for its purpose.

If the soda ash, which is the starting material, does not already have a grain size suitable for mixing, it is ground and classified into the appropriate grain size mentioned above before mixing.

Accordingly, the grain size of the powdery slag D95 used for the mixture is suitably between 10 and 40 µm, preferably between 20 and 25 µm. If the slag does not already have this grain size, it must be ground to that size before mixing and, in order to achieve the best result, it must also be classified in terms of grain size as uniform as possible. Advantageously, the slag is granulated before grinding.

When preparing the binder according to the invention for ground reinforcement and/or stabilization of roadbeds, it can be advantageous to also add fiber to the binder combination, for example torn textile pulp. This gives the mixture toughness and tensile strength.

The cement-like binder according to the invention is preferably used, for example, as one ingredient in the material used to fill mines, for soil stabilization to strengthen loose soil, as a binder in building materials, in asphalt construction and also in other areas where a binder that is strengthened in this way can be used.

The binder according to the invention can be produced anywhere

N in a suitable place. A mixture of powders with a suitable grain size

Mixing of N 25 substances, i.e. APC ash and slag or soda ash 3 can be done, for example, at a mixing station or also at the place of use

With S x a

Oo It is clear to a person skilled in the art that the different application forms of the invention are not limited to the examples presented above, but may vary within the framework of the patent claims presented below. It is essential that the expensive and difficult to dispose of and dangerous fly ash from the combustion of municipal waste, i.e. mixed waste, i.e. APC ash, can be utilized and recycled according to the invention by mixing it with suitably selected other substances.

It is also clear to a person skilled in the art that if the calcium oxide content of the ash used for the production of the binder according to the invention is so low that simply mixing the ash with slag or soda ash does not achieve such a reaction that, for example, the binder would strengthen to the intended strength, the said ash can be used for the mixture in addition, some other ash or similar substance, such as for example waste plaster with a sufficiently high calcium oxide content.

In this case, the combined calcium oxide content of the substances to be mixed is sufficient to cause such a reaction that when using the binder according to the invention as a building material and for other suitable uses, it consolidates to a strength suitable for the purpose and is also a harmless substance for the environment.

The same can also apply to other ingredients in the ash than calcium oxide, which ingredients may be important for some other properties of the binder. In this way, if necessary, the calcium oxide content of the binder mixture and also the concentrations of other ingredients can be corrected with a suitable third substance.

OF

N 25 It is also clear to a professional in the field that, depending on the composition of the APC-3 waste, it is not necessary to manually

No way in the binder combination. In this case, as APC waste

The ash in E can be mixed as it is either with the slag mentioned above or with soda ash. The binder 2 30 made in this way does strengthen, but more slowly and the strength values remain low.

O more fat than if ground and/or graded had been used

APC ash.

Claims (13)

PATENT CLAIMS 1. A method for processing municipal waste or mixed waste incineration ash, in which a binder mixture is formed in which the fly ash of municipal waste or mixed waste incineration, i.e. APC ash, is mixed as an activator either with slag generated in metal production as a side stream of production or with soda ash generated in the forest industry, characterized by the fact that APC ash and slag or APC ash and soda ash are mixed together as a dry powder with a D95 grain size between 10 and 40 µm, preferably between 20 and 25 µm. 2. The method according to claim 1, characterized by the fact that the classified and, if necessary, additionally ground APC ash is mixed with the slag produced as a side stream of production less than approx. 40%, preferably less than approx. 25%, and that the slag is granulated and, if necessary, ground and classified before mixing. 3. The method according to claim 1 or 2, characterized in that APC ash is mixed with the slag generated as a by-product of production in weight percentages N%, where N is given all integer values with their decimal parts between 1-40. No. 25 4. The method according to claim 1, characterized by 3 that the soda ash formed as a side stream of the production is mixed Q dry with APC ash at most approx. 50%, preferably at most approx. E 25%. D o 30 5. The method according to claim 1 or 4, characterized by the fact that the classified and, if necessary, additionally ground APC ash is mixed dry with the soda ash produced as a side stream of production in weight percentages N%, where N gets all the total numerical values with decimal parts between them between 50-90, and that the soda ash is dried and, if necessary, ground and classified before mixing. 6. A method according to one of the above claims, characterized in that APC ash is mixed with the slag or soda ash generated as a side stream of the production, which comprises calcium oxide (CaO) in weight percentages of no more than approx. 70%, suitably approx. 50-65%, and preferably more 40%. 7. A binder with ash as one ingredient, which binder comprises fly ash from the combustion of municipal waste, or mixed waste, acting as an activator, i.e. APC ash and either slag from metal production as a side stream of production or soda ash from the forest industry as a side stream of production, characterized by the fact that the binder comprises APC ash and either slag or soda ash mixed together as dry powders with a D95 grain size between 10 and 40 µm, preferably between 20 and 25 µm. 8. Binder according to claim 7, characterized in that the binder comprises APC ash at most approx. 40%, preferably at most approx. 25% mixed with SW slag generated as a side stream of production. No 9. Binder according to claim 7 or 8, characterized in that the binder comprises APC ash in weight percent N%, Ek where N gets all integer values with decimals between them between 1-40 mixed as a side stream of production = 30 to the slag generated . O S 10. Binder according to claim 7, characterized in that the binder comprises soda ash produced as a side stream of production precipitate mixed with dry APC ash at least approx. 10%, advantageously at most approx. 25% and at most approx. 50%. 11. Binder according to claim 7 or 10, characterized in that the binder comprises APC ash in weight percent N%, where N gets all integer values with their decimal parts between 50-75 mixed with the soda ash produced as a side stream of production. 12. A binder according to one of the above claims 7-11, characterized in that the binder comprises calcium oxide (Ca0) in weight percentages of no more than approx. 70%, suitably approx. 50-65%, and preferably more than 40%. 13. Use of a binder according to any of claims 7-12 as one or more of the following: as a binder in earth construction and soil reinforcement, and as a binder in the stabilization of roadbeds and other land areas, or in mine filling, as a binder in building materials, as a binder in asphalt construction, and as a binder in other uses. N N O N 0 <Q 0) N I Jami a oO O LO O N O N