WO2020249872A1

WO2020249872A1 - Method for handling of ash of burned municipal waste, a product formed with said method and use of said product

Info

Publication number: WO2020249872A1
Application number: PCT/FI2020/050420
Authority: WO
Inventors: Aino Heikkinen-Mustonen
Original assignee: Fatec Oy
Priority date: 2019-06-12
Filing date: 2020-06-12
Publication date: 2020-12-17
Also published as: EP3983351A1; EP3983351A4

Abstract

The invention relates to a method of handling ash from the combustion of municipal waste, i.e. mixed waste. In the method according to the invention, a cement-based binder composition is created where cement powder is blended with ash from municipal waste, i.e. mixed waste, combustion, i.e. with APC ash. The method also relates to products made by the method and to the use thereof.

Description

METHOD FOR HANDLING OF ASH OF BURNED MUNICIPAL WASTE, A PRODUCT FORMED WITH SAID METHOD AND USE OF SAID PRODUCT

The invention relates to a method of handling ash from mu- nicipal waste combustion as defined in the preamble of claim 1, as well as to a product made by the method as de fined in the preamble of claim 7 and to the use of the product as defined in the preamble of claim 15. In the production of electrical and thermal energy, a vari ety of combustion plants are generally used, the ash pro duced by them being further processed case-specifically in different ways. Said plants employ, as a fuel, i.a., coal, wood, bark, peat and other biofuels, as well as natural gas, oil and, increasingly, municipal waste which also can be referred to as "mixed waste".

Depending on the fuel employed by the plant, the ash must be disposed of, i.a., for environmental reasons, in varying ways. When the plant operates as an incinerator, it usually employs said mixed waste as waste and produces, when incin erating the waste, slag, boiler and fly ash as well as so- called APC waste, which, even mixed with other fly ash, is harmful and even dangerous for the people and environment. APC is an abbreviation of Air Pollution Control. APC waste is a side-stream fly ash material from incineration, also referred to as APC ash and APC fly ash, hereafter in this specification . The utilization of APC ashes from incineration is compli cated by the fact that they contain substances which are classified as dangerous. These APC ashes contain, i.a., heavy metals. Therefore, APC ashes from mixed waste combus- tion cannot be disposed to landfills, for example, without specific investigations. Their disposal to landfills is possible only after specific eligibility criteria are ful filled. If the eligibility criteria are not fulfilled, said APC ashes are classified as dangerous waste and need to be disposed of or destroyed at sites reserved for them. The disposal of APC ashes is an increasing problem.

However, all APC ash is not this dangerous throughout. Therefore, one problem with the mixed waste combustion is, in particular, that a far too large amount of APC fly ash recyclable for other use is disposed to landfills. By ap propriate processing, a major part of the APC fly ash cur rently obtained from the combustion of mixed waste, which is in the form of municipal waste, by the incinerators could be utilized as an additional constituent in cement that does not have to be the highest guality cement.

Coal plant and bioplant fly ash, which is substantially harmless to the environment, has already been used as an additional constituent in the manufacture of concrete in the prior art but the results have not necessarily been good enough in terms of the achieved strength of the con crete, resulting from that the fly ash has generally been used as such, completely unsorted. This has increased the quality of the concrete blended with the unsorted fly ash only to some extent or not at all. The fly ash content of the fly ash cements of the prior art solutions usually is approximately 15 to 40 %, consisting of the above-mentioned environmentally substantially harmless fly ash. Typically, the use of unprocessed fly ash is seasonal, quantitatively restricted and results in low gained benefits, under strict technical constraints. By adding unsorted APC fly ash, after letting it pre-age, to cement powder, concrete compressive strength values sim ilar to those of the sorted fly ash according to the inven- tion can eventually be achieved. However, the problem is that it remains unclear, unless separate time-consuming measurements are carried out, if the achieved compressive strength is high enough. Besides, as the fly ash does not age into uniform material automatically, the use of pre- aged fly ash does not result in material uniform enough for use as a cement additive. The solution according to the in vention, instead, immediately produces a sufficiently uni form and useful fly ash product, also allowing APC waste to be used as a raw material.

Ground blastfurnace slag, which is a by-product from crude iron manufacture, has also been used as an additional con stituent for cement. As early as in 1981 and 1982, Aino Heikkinen, the inventor of the present invention, studied, in a Finnish company called Lujabetoni Oy, not only the use of blastfurnace slag in concrete structures but also the use of fly ashes from peat combustion as a cement additive. Table 1 below discloses a part of Aino Heikkinen's trial and research results from those years.

Table 1.

The object of these studies carried out by Aino Heikkinen in 1981 and 1982 was the compressive strength of concrete types as a function of time. The second column of Table 1 represents a trial from 28.1.1981, using, as a binder, not ordinary cement but fine ground and also alkali-activated blastfurnace slag. The compressive strength, which was studied according to the standards, increased very fast and reached, after just 1 day, a value of 49 MPa. As a rule, the strength value meeting the standard strength quality requirements must be reached within 28 days, at the latest.

The third column of Table 1 represents a trial from

3.2.1981, where cement of type CEM I is blended with peat combustion fly ash in an amount of 20 %. In this case, the compressive strength values are not measured hourly but the first measurement value was taken at 1 day. In this case, the strength has also increased very fast and reached, af ter just 1 day, a value of 59 MPa.

For comparison, Aino Heikkinen carried out one more trial, approximately one year after said two trials, i.e.

3.2.1982, studying the compressive strength of concrete produced by unblended, i.e. 100 % cement of type CEM 1, in the same way as the compressive strength of the two other binders shown in Table 1 was studied. The result indicates that the increase of the strength of this unblended 100 % cement has been slower than the increase of the strength of the concrete made out of blastfurnace slag or of the con crete made out of cement blended with peat combustion fly ash .

Based on these tests and trial results from the early 1980's, Lujabetoni Oy manufactured, industrially, as early as in 1981, alkali-activated high-strength concrete from 100 % blastfurnace slag. These concrete structures are still in use industrial buildings, without any structural damages. Peat combustion fly ash was also industrially uti lized in the manufacture of concrete in the 1980 's, until the Chernobyl nuclear accident after which Finland also took precautions for any deposits on peatlands.

Cement chemistry has remained almost unchanged for approxi mately 1000 years but it is changing now that the binder is composed of combinations of different materials. This may result in a binder that is more durable than the commonly known Portland cement. The new binder compositions may also hold surprises in the form of long-term durability and dif ferent kinds of stresses and must therefore be tested as carefully as possible before the materials are used in bearing structures, for example.

This invention aims at eliminating the above-mentioned drawbacks as well as to provide an inexpensive and reliable method of handling ash from municipal waste combustion. An objective of the invention is to provide a product produced by the method and employing ash from municipal waste com bustion as an additive in cement. Further, an objective of the invention is to make it possible to maximize the utili zation of ash from municipal waste combustion, thus expand- ing the possibilities for the disposal of the ash. The method according to the invention is characterized in what is set forth in the characterizing part of claim 1. Corre spondingly, the product produced by the method according to the invention is characterized in what is set forth in the characterizing part of claim 7 while the use of the product is characterized in what is set forth in the characterizing part of claim 15. The other of the embodiments are charac terized in what is set forth in the rest of the claims.

Typically, the method of handling ash from municipal waste, i.e. mixed waste, combustion produces a cement-based binder combination where cement powder is blended with fly ash from municipal waste, i.e. mixed waste, combustion, i.e. with APC ash.

Typically, the cement-based binder combination produced by the method according to the invention contains, as one con stituent, cement powder or cement-like powder, and, in ad dition, fly ash from municipal waste, i.e. mixed waste, combustion, i.e. APC ash. Hereafter, the cement powder or the cement-like powder will each be briefly referred to as "cement powder".

Preferably, the binder combination according to the inven tion contains cement powder in an amount of approximately 75 %, APC ash in an amount of approximately 10 to 15 % and substantially unharmful ground slag, fly ash from bark com bustion or other substantially unharmful fly ash in an amount of approximately 10 to 15 %, the percentage of the two latter ones being portioned in such a way that their percentage is approximately 25 % in total. A significant advantage of the solution according to the invention is that it allows ash from municipal waste com bustion to be utilized as far as possible. This makes it possible to replace a part of cement powder with ash and, thus, in the concrete industry, to drop the C02 emissions of the cement manufacture as the fly ash replacing a part of the cement reduces the amount of cement needed in the manufacture of the concrete. This type of cement is suited for use as ground reinforcements and stabilizers, for exam- pie. Likewise, the cement manufactured in this way can also be used for applications not requiring the strength and other properties of higher quality cements. This type of cement is well-suited for manufacturing concrete slabs and garden stones as well as different kinds of support struc- tures, for example. Besides, it has a much smaller ecologi cal footprint than the current APC fly ash.

Cement used for making concrete is categorized according to its additional constituents and strength classes. Construc tion cements are divided into different quality classes, i.e. types, based on the ratio of clinker, their basic material, and the additional constituents, cement of type CEM I con taining the smallest amount, i.e. up to 5 %, of additional constituents. Correspondingly, CEM III cement may contain a significantly higher level of additional constituents and up to 80 % of blastfurnace slag. The strength class of cement of type CEM III is denoted by 32.5 R or 32.5, depending on the speed class. This means that the compressive strength of ce ment of type CEM III must be 32.5 to 52.5 MPa, at 28 days of curing, at the latest. Thus, blended cement must meet the re quirement of the lower limit of 32.5 MPa of the compressive strength in order to be accepted as cement of type CEM III. This invention allows so-called APC waste, i.e. fly ash mate rial produced as a side-stream of waste combustion and con taining harmful and/or dangerous substances to be safely used as a raw material in manufacturing cement, this cement being further usable, i.a., as a ground stabilizer and for manufac turing concrete. Fly ash produced by combusting municipal waste can be used as a cement constituent in an amount of up to 50 % of the amount of the cement powder, an upper limit, and a quite safe upper limit, preferably being approximately 20 to 25 % and approximately 15 %, respectively. However, the amounts blended can also be smaller, and, therefore, instead of the current non-existent use of APC fly ash, it can be used overall in amount of 0 to 50 % of the amount of the en tire mixture. Said percentages are percentages by weight.

Table 2 discloses the results of trials carried out by the applicant for finding out how harmful substances are dis solved in concrete specimens prepared by using cement where a part of the cement powder is replaced with sorted, and, when necessary, ground APC waste fly ash.

Table 2.

Correspondingly, Table 3 shows the limit values set for harm ful substances as well as the maximum thickness of the waste layer according to Government Decree 843/2017.

Table 3.

It appears from Tables 2 and 3 that, in concrete specimens prepared by using cement where a part of the cement powder is replaced with sorted, and, when necessary, ground APC waste fly ash, the concentrations of dangerous and harmful sub stances in most cases are below the limit values set for harmful substances by Government Decree 843/2017, at the con- struction sites mentioned in Table 3. Let us take molybdenum as an example and explain the contents of Table 2. In the first three of the specimens, cement powder is blended with sorted and, when necessary, ground fly ash from APC waste combustion in an amount of 50 %, whereas, in the latter three specimens, cement powder is blended with sorted and, when necessary, ground fly ash from APC waste combustion in an amount of 15 %. It appears from Table 2 that, in all of the specimens 1 to 6, the solubility values of molybdenum are be low the limit values according to Government Decree 843/2017, in all of the construction sites except for field structures where the ground is not paved but only covered. There, the limit value is 0.5. However, the solubility values of spec imens 4 to 6, which only contain fly ash in an amount of 15 %, are below this limit value.

A binder composition containing cement in an amount of ap proximately 85 % and sorted, either fine or coarse APC fly ash in an amount of approximately 15 % has the specific fea ture that concrete made out of it, compared to blastfurnace slag compositions, for example, has a high development of in itial strength. According to the invention, it is preferable to first categorize the APC fly ash into at least two differ ent particle size classes and to use the APC fly ash in this categorized form. Fly ash with coarse particles must then be ground finer. The categorization allows the element concen trations in the ash to be distributed in a favorable way, without having a significant detrimental effect on the devel opment of the compressive strength of concrete, for example. The categorization is even more significant at a high blend ing ratio when the amount of APC fly ash used for the cement mixture is approximately 50 %, for example. If the mixture contains unsorted APC fly ash in an amount of approximately 50 %, consisting of both fine APC fly ash and coarse APC fly ash, the development of the compressive strength slows down dramatically .

Instead of, or in addition to, fly ash from mixed waste com bustion, cement can also be blended with different, fine- ground slag or fly ash from tree bark or rind combustion. Ta ble 4 is a simplified representation of trial results of studies carried out in 2015 and 2016 and testing, in the form of a prism test, the effect of two different slag types and two bark ashes having a different particle size on the devel opment of the compressive strength of cement.

Table 4 shows the results of trials carried out by the appli cant and concerning cement of type CEM I blended with differ ent kinds of slags and fly ashes bark combustion as addition al constituents. The binder compositions obtained were used for making concrete and the development of its compressive strength was measured by standard tests.

Table 4.

The second column of Table 4 represents a trial where ce ment of type CEM I was blended with granulated Merox slag, which was produced in Sweden, in an amount of 65 %. The amount of cement powder in the mixture was approximately 35 %. The lower limit of 32.5 MPa of the compressive strength of cement of type CEM III is exceeded as early as at 14 days of curing, that is, this binder combination, in terms of strength, is well above the lower limit set for cement of type CEM III.

Correspondingly, the third column of Table 4 represents a trial where cement of type CEM I was blended with granulat ed Cement Bow slag, which was produced in Germany, in an amount of 50 %. The amount of cement powder in the mixture was approximately 50 %. The lower limit of the compressive strength of cement of type CEM III is exceeded as early as at 7 days of curing, that is, this binder combination, in terms of strength, is also well above the lower limit set for cement of type CEM III.

The fourth and fifth columns of Table 4 represent a trial where cement of type CEM I was blended with fly ash from tree bark and/or rind in an amount of 25 %. The amount of cement powder in the mixture was approximately 75 %. In the first and the second trial, the cement was blended with me dium-fine bark ash and fine bark ash, respectively. In both cases, the lower limit of the compressive strength of ce ment of type CEM III is exceeded as early as at 14 days of curing, that is, this binder combinations, in terms of strength, are also well above the lower limit set for ce ment of type CEM III. Table 5 discloses the results of other trials carried out with other binder combinations which also meet at least the strength class requirements imposed on cement of type CEM

ITT .

The second column of Table 5 represents a trial where ce ment of type CEM I was blended with APC ash from municipal waste combustion and with stainless steel slag from steel manufacture in an amount of 10 % and 13 %, respectively.

Thus, the amount of cement powder in the mixture was ap proximately 77 %. The lower limit of 32.5 MPa of the com pressive strength of CEM III cement is exceeded at 28 days of curing, that is, this binder combination, in terms of strength, is well above the lower limit set for cement of type CEM III.

The third column of Table 5 represents a trial where cement of type CEM I was blended with APC ash from municipal waste combustion and with coarse stainless steel slag from steel manufacture in an amount of 13 % and 10 %, respectively. Thus, the amount of cement powder in the mixture was ap proximately 77 %. The lower limit of 32.5 MPa of the com pressive strength of cement of type CEM III is exceeded at 28 days of curing, that is, this binder combination, in terms of strength, is also well above the lower limit set for cement of type CEM III.

The fourth column of Table 5 represents a trial where ce ment of type CEM I was blended with APC ash from municipal waste combustion and with coarse stainless steel slag from steel manufacture in an amount of 50 % and 7 %, respective ly. Thus, the amount of cement powder in the mixture was approximately 43 %. The result of this case is nowhere near the lower limit of the compressive strength of cement of type CEM III, and, in addition, the specimen cracked and expanded. This binder combination, as it is, does not ex ceed the lower limit set for cement of type CEM III.

Tables 6 and 7 disclose binders prepared with different blending ratios of CEM I Embra cement powder and APC ash from municipal waste combustion as well as the post-curing compressive strength values of concrete specimen pieces made thereof, measured at 1 day, 3 days and 28 days of cur ing. In the trial conditions, the APC ash, i.e. APC fly ash, was categorized into two different particle classes, i.e. APC ash with fine particles and coarse APC ash, the coarse APC ash being ground even finer. This procedure halved the harmful and dangerous constituents contained in the APC ash.

Table 7.

The second column of Table 6 discloses a trial where CEM I Embra cement was blended with categorized, fine particulate APC ash from municipal waste combustion in an amount of 5 %. Thus, the amount of cement powder in the mixture was ap proximately 95 %. The lower limit of 32.5 MPa of the com pressive strength of cement of type CEM III is exceeded as early as at 7 days of curing, that is, this binder combina tion, in terms of strength, is well above the lower limit set for cement of type CEM III.

The third column of Table 6 discloses a trial where CEM I Embra cement was blended with categorized, coarse particu late APC ash from municipal waste combustion in an amount of 5 %. Thus, the amount of cement powder in the mixture was approximately 95 %. The lower limit of 32.5 MPa of the compressive strength of cement of type CEM III is exceeded as early as at 7 days of curing, that is, this binder com bination, in terms of strength, is well above the lower limit set for cement of type CEM III.

The fourth column of Table 6 discloses a trial where CEM I Embra cement was blended with categorized, fine particulate APC ash from municipal waste combustion in an amount of 15 %. Thus, the amount of cement powder in the mixture was ap proximately 85 %. The lower limit of 32.5 MPa of the com pressive strength of cement of type CEM III is exceeded at 28 days of curing, that is, this binder combination, in terms of strength, is well above the lower limit set for cement of type CEM III.

The fifth column of Table 6 discloses a trial where CEM I Embra cement was blended with categorized, coarse particu late APC ash from municipal waste combustion in an amount of 15 %. Thus, the amount of cement powder in the mixture was approximately 85 %. The lower limit of 32.5 MPa of the compressive strength of cement of type CEM III is exceeded at 28 days of curing, that is, this binder combination, in terms of strength, is well above the lower limit set for cement of type CEM III.

Correspondingly, the second column of Table 7 discloses a trial where CEM I Embra cement was blended with catego rized, fine particulate APC ash from municipal waste com bustion in an amount of 25 %. Thus, the amount of cement powder in the mixture was approximately 75 %. The lower limit of 32.5 MPa of the compressive strength of cement of type CEM III is not exceeded at 28 days of curing, that is, this binder combination, in terms of its strength, is not above the lower limit set for cement of type CEM III.

Correspondingly, the third column of Table 7 discloses a trial where CEM I Embra cement was blended with catego rized, coarse particulate APC ash from municipal waste com bustion in an amount of 25 %. Thus, the amount of cement powder in the mixture was approximately 75 %. In this case, the lower limit of 32.5 MPa of the compressive strength of cement of type CEM III is not exceeded at 28 days of cur ing. However, as the measured value 32.15 MPa falls just short of this value, changing the blending ratio by a few percent might be enough for reaching said lower limit. As an example, a blending ratio of 80 % of cement powder and 20 % of APC ash might result in a value above the lower limit and in this binder combination exceeding, in terms of its strength, the lower limit set for cement of type CEM III .

Correspondingly, the fourth and fifth column of Table 7 discloses trials where CEM I Embra cement was blended with categorized APC ash from municipal waste combustion in an amount of 50 %. Thus, the amount of cement powder in the mixture was approximately 50 %. In these cases, as the low er limit of 32.5 MPa of the compressive strength of cement of type CEM III is not exceeded at 28 days of curing, that is, these binder combinations do not exceed, as they are, the lower limit set for cement of type CEM III.

The coarse additional constituent stated in Tables 5 to 7, either slag or fly ash categorized as coarse, i.e. sorted fly ash, is ground even finer before it is mixed in as an additional constituent.

Table 8 discloses a binder prepared with a blending ratio 50:50 of CEM I Embra cement powder and uncategorized APC ash from municipal waste combustion as well as post-curing compressive strength values measured on concrete specimens made thereof, at 1 day, 7 days and 28 days of curing.

Table 8. The second column of Table 8 discloses a trial where CEM I Embra cement was blended with uncategorized APC ash from municipal waste combustion in an amount of 50 %. Thus, the amount of cement powder in the mixture was also approxi mately 50 %. Since the specimen piece decomposed in water within 1 day, no proper strength measurement could be per formed thereon. This binder combination does not exceed, in terms of its strength, the lower limit set for cement of type CEM III.

The third column of Table 8 discloses a trial similar to the one in the second column of Table but, in this trial, the specimen pieces were initially stored at room tempera ture for 7 days and the first strength measurement as per formed only after 11 days. In this case, as the lower limit of 32.5 MPa set for the compressive strength of cement of type CEM III is not exceeded at 28 days of curing, this binder combination does not exceed, in terms of its strength, the lower limit set for cement of type CEM III.

Until now, it has not been possible to freely recycle or to freely dispose of fly ash, i.e. APC ash originating from the combustion of municipal waste, more commonly mixed waste, as it contains compounds harmful and dangerous to humans, animals and the environment. The applicant has been able to develop, based on his numerous studies and trials, a novel innovative solution for utilizing APC ash in an in expensive and safe way. In this solution, ready-to-use ce ment, suitably consisting of cement powder of type CEM I and already containing the smallest portion of additional constituents, is blended with APC ash, preferably in dry form. This results in a novel and innovative cement-based binder useful for manufacturing different types of concrete and concrete products, as an injecting compound, a mine filler, a ground stabilizer for reinforcing loose soil, etc .

As appears from the results of the trials, the binder com bination, i.e. binder composition, or, even more briefly binder, according to the invention, may merely consist of a portion of cement powder and a portion of APC ash, prefera bly categorized APC ash, but, in addition to the cement powder and the APC fly ash, the binder combination may also consist of a portion of granulated slag, preferably blastfurnace slag, and/or of a portion of tree rind or bark combustion fly ash. It can be stated that the solution ac cording to the invention comprises preparing a binder com bination, the use thereof and the binder combination it self, the binder combination containing a given percentage of cement powder and a given percentage of APC fly ash, which preferably has been categorized and also ground after the categorization, if necessary. Said binder combination may also contain a given percentage of one or more of the following additional constituents: stainless steel slag, other blastfurnace slag, fly ash from tree rind combustion, fly ash from bark combustion, fly ash from peat combustion, fly ash from wood combustion, fly ash from other biocombus tion, fly ash from coal combustion. Said binder combination may further contain a variety of additives which may or may not be already contained in in the cement powder that is used .

In the method according to the invention, said binder com bination is prepared, preferably in dry form, by blending cement powder, preferably cement powder of type CEM I, with fly ash, i.e. APC ash, from the combustion of municipal waste, i.e. more commonly mixed waste, in an amount of N % . Preferably, the APC ash that is mixed in is categorized ash, such as ash directly categorized as fine ash, or ash initially categorized as coarse ash and ground fine there after. The percentage N is a percentage by weight and any percentage in the range of 0 to 50 %, suitably one at a time from the following integers and their decimals: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 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. That is, more briefly, the percentage N may have any numerical value with decimals in the integer range of 0 to 50.

As appears from the results of the trials, one quite safe percentage N of APC ash is 15. When cement powder of type CEM I is blended with APC ash, either fine or coarse, the compressive strength of all of the concrete specimens made out of this binder combination reached the values of cement of type CEM III. It is probable that the values of cement of type CEM III also are reached by using APC fly ash per centage N by weight values of approximately 16, 17, 18, 19 and 20.

If other additional constituents are desirable in the bind er combination that is prepared, they are mixed into the binder combination, in addition to the cement powder and APC ash. Thus, one exemplary preferable binder combination contains cement, preferably cement of type CEM I in an amount of 75 %, APC fly ash in an amount of 10 to 15 % and bark combustion fly ash in an amount of 10 to 15 % or some other substantially non-hazardous additional constituent mentioned above, the APC ash and the other additional con- stituent being portioned in such a way that their total percentage is 25 %.

The cement-based binder combination according to the inven tion can be prepared in any appropriate place. The blending can be done at a concrete station, blending station or the application site, for example.

The cement-based binder combination according to the inven tion itself contains cement powder, preferably cement pow der of type CEM I, blended with fly ash from municipal waste, i.e. more commonly mixed waste, combustion, i.e. with APC ash, in an amount of N % . Preferably, the APC ash that is mixed in is categorized ash, such as fine or coarse ash, the coarse ash also being ground finer after the cate gorization. An average coarseness of approximately 25 pm can be defined as the limit between fine and coarse ash. Thus, fine ash has an average coarseness D50 lower than 25 pm, while coarse ash has an average coarseness D50 higher than 25 pm.

The percentage N is a percentage by weight and any percent age in the range of 0 to 50 %, suitably any of said values of the percentage N.

Preferably, the cement-based binder according to the inven tion is used for manufacturing different types of concrete and concrete products, as an injecting compound, a mine filler, a ground stabilizer for reinforcing loose soil, etc .

When preparing the binder according to the invention for reinforcing ground and/or stabilizing road beds, it is preferable to add not only cement powder and APC ash but also fiber, such as such textile shred, to the binder com bination. This provides the mixture with toughness and ten sile strength.

It will be appreciated by a person skilled in the art that the different embodiments of the invention are not solely restricted to the examples given above but may vary within the scope of the accompanying claims. What is essential is that the invention allows fly ash from municipal waste, i.e. mixed waste, combustion, i.e. APC ash, which is expen sive and difficult to dispose of, to be utilized and recy cled by suitably mixing it with cement.

It will also be appreciated by the person skilled in the art that the ready-to-use cement powder constituting the basic substance of the binder combination does not have to be the above-mentioned cement powder of type CEM I. Other cement powders belonging to other categories of type and having a higher level of other additional constituents al ready contained therein can be used just as easily. In the preparation of the binder combination, the other additional constituents already contained must be taken into account when blending the binder combination with APC ash and pos sibly other individual additional constituents. As an exam ple, the percentage of the APC ash and other individual ad ditional constituents is lower than when using cement pow der of type CEM I as the basic substance.

Claims

1. A method of handling ash from the combustion of munici pal waste, i.e. mixed waste, characterized in that a ce ment-based binder combination is created by blending cement powder with fly ash from the combustion of municipal waste,

1.e. mixed waste, i.e. with APC ash, categorized by parti cle size.

2. A method as defined in claim 1, characterized in that cement powder is blended with APC ash in an amount of up to 50 %, suitably in an amount of up to approximately 20 % and preferably in an amount of up to approximately 15 %.

3. A method as defined in claim 1 or 2, characterized in that cement powder is blended with APC ash in an N percent age by weight where N has any numerical value with decimals in the integer range of 0 to 50.

4. A method as defined in claim 1, 2 or 3, characterized in that, when necessary, cement powder not only is blended with APC ash categorized by particle size but also with ground APC ash.

5. A method as defined in any of the preceding claims, characterized in that the binder combination is blended not only with cement powder and APC ash but also with one or more of the following: ground stainless steel slag, other ground blastfurnace slag, fly ash from tree rind combus tion, fly ash from bark combustion, fly ash from peat com bustion, fly ash from wood combustion, fly ash from other biocombustion, fly ash from coal combustion.

6. A method as defined in any of the preceding claims, characterized in that APC ash is mixed with cement powder, typically cement powder of type CEM I, in dry form.

7. A cement-based binder combination containing cement pow der as one constituent, characterized in that the binder combination contains not only cement powder but also fly ash from municipal waste, i.e. mixed waste, combustion, i.e. APC ash, categorized by particle size.

8. Binder combination as defined in claim 7, characterized in that the binder combination contains APC ash in an amount of up to 50 %, suitably in an amount of up to ap proximately 25 % and preferably in an amount of up to ap proximately 15 %.

9. Binder combination as defined in claim 7 or 8, charac terized in that the binder combination contains APC ash in an N percentage by weight where N has any numerical value with decimals in the integer range of 0 to 50.

10. Binder combination as defined in any of the preceding claims 7 to 9, characterized in that the binder combination comprises not only cement powder and APC ash but also one or more of the following: ground stainless steel slag, oth er ground blastfurnace slag, fly ash from tree rind combus tion, fly ash from bark combustion, fly ash from peat com bustion, fly ash from wood combustion, fly ash from other biocombustion, fly ash from coal combustion.

11. Binder combination as defined in any of the preceding claims 7 to 10, characterized in that the binder combina- tion comprises not only APC ash categorized by particle size but also ground APC ash.

12. Binder combination as defined in any of the preceding claims 7 to 11, characterized in that the binder combina tion comprises cement powder of type CEM I.

13. Binder combination as defined in any of the preceding claims 7 to 11, characterized in that the binder combina tion comprises cement powder in an amount of approximately 80 to 90 % and APC ash in an amount of approximately 20 to 10 %, preferably cement powder in an amount of approximate ly 85 % and APC ash in an amount of approximately 15 %.

14. Binder combination as defined in any of the preceding claims 7 to 11, characterized in that the binder combina tion comprises cement powder in an amount of approximately 75 %, APC ash in an amount of approximately 10 to 15 % and a substantially unharmful ground slag, fly ash from bark combustion or some other non-harmful fly ash in an amount of approximately 10 to 15 %, the percentage of the two lat ter ones being portioned in such a way that their total percentage is 25 %.

15. Use of a binder composition defined in claim 7 as one or more of the following: a binder for manufacturing dif ferent types of concrete and concrete products, and/or for preparing an injecting compound, and/or for construction and ground reinforcement, as well as a binder for stabiliz ing road beds and other land areas, or for mine filling.