Method for manufacturing cement mixture

Abstract

To provide a technology capable of effectively utilizing a biomass ash while suppressing increases in the chlorine content of a cement mixture.SOLUTION: A method for producing a cement mixture includes: a step (a) of classifying a biomass ash into a coarse powder and a fine powder with a reference value in a range of 30 μm to 100 μm as a classification point; and a step (b) of mixing the coarse powder obtained in step (a) with cement and water without grinding, wherein: the coarse powder obtained in the step (a) has a chlorine (Cl) content of 0.2 mass% or less before undergoing the washing step; and the step (b) is a step of mixing the coarse powder, which has an amorphous ratio of 60 mass% or less, with the cement and water.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a cement kneaded body containing biomass ash powder particles and a method for producing the same.

Background Art

[0002] Incineration ash generated by incineration of municipal waste, etc., has been desired to be recycled as a cement raw material, etc., in recent years against the background of the increasing pressure on disposal sites. In addition, due to various efforts towards the spread of renewable energy, the construction and operation of biomass power generation facilities have been progressing, and the amount of incineration ash (biomass ash) generated by biomass power generation is also increasing. Therefore, it is expected that biomass ash will be recycled as a cement raw material, etc., in the same way as incineration ash of municipal waste, etc.

[0003] In relation to such problems, for example, in Non-Patent Document 1 below, the application of biomass ash as a cement admixture has been studied.

Prior Art Documents

Non-Patent Documents

[0004]

Non-Patent Document 1

[1307]

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, from an environmental perspective, there has been a demand for alternative materials to mountain sand and river sand used as aggregates in concrete production. Meanwhile, biomass such as palm oil stalks is attracting attention as a carbon-neutral fuel, and its use is on the rise. This trend is resulting in the generation of large quantities of biomass ash. Therefore, in order to prevent the strain on biomass ash disposal sites, there is a need to utilize biomass ash. Accordingly, the inventors of this invention are considering using biomass ash as an alternative material for aggregates.

[0006] In the above Non-Patent Document 1, the compressive strength of a mortar specimen was verified by classifying incinerated ash obtained by burning woody biomass alone using a sieve with a classification point of 90 μm, and then replacing 10% of the sieved residue (coarse powder) with the amount of fine aggregate material.

[0007] However, biomass ash contains a large amount of chlorine. If concrete is manufactured using a fine aggregate substitute obtained by the method described in Non-Patent Document 1, the chlorine content of the concrete may exceed regulatory limits, potentially causing rebar corrosion.

[0008] The present invention aims to provide a technology that can effectively utilize biomass ash while suppressing an increase in the chlorine content of cement mixtures such as concrete. [Means for solving the problem]

[0009] The biomass ash powder granules according to the present invention are characterized in that the cumulative volume percentage of the particle size distribution has a value of 35 μm or more at 10% (D10).

[0010] According to the above configuration, biomass ash granules with a suppressed chlorine (Cl) content are realized. When these biomass ash granules are used as a partial substitute material for fine aggregate to manufacture a cement mixture, it is possible to suppress the increase in the amount of chlorine contained in the resulting cement mixture. In other words, the biomass ash granules may also be used as a substitute for fine aggregate in cement mixtures.

[0011] In this specification, "cement mixture" is a concept that includes concrete and mortar, encompassing both the pre-hardening and post-hardening states. Furthermore, "hardened cement product" refers to the state after the cement mixture has hardened.

[0012] Among biomass ash, the coarse powder with relatively larger particle sizes has lower calcium, sulfur, chlorine, and carbon content compared to the fine powder with relatively smaller particle sizes. Therefore, by setting D10 to 35 μm or more, a biomass powder with a low chlorine content (chlorine concentration) can be obtained. More preferably, the D10 of the biomass ash powder is 50 μm to 115 μm. By setting the D10 of the biomass ash powder to 115 μm or less, the binding effect (pozzolanic reaction) can be expected, thus ensuring the strength of the hardened cement. From a similar viewpoint, it is preferable that the cumulative volume percentage of the particle size distribution of the biomass ash powder at 90% (D90) is set to 80 μm to 400 μm.

[0013] Furthermore, the value (D50) at which the cumulative volume percentage of the particle size distribution of the biomass ash powder particles reaches 50% is preferably 100 μm to 300 μm, more preferably 150 μm to 250 μm, and particularly preferably 175 μm to 200 μm.

[0014] The particle size distribution of the biomass ash powder can be measured, for example, by a laser diffraction / scattering type particle size distribution analyzer.

[0015] The chlorine (Cl) content of the biomass ash powder granules is preferably 0.1% by mass or less, and more preferably 0.05% by mass or less.

[0016] The proportion of chlorine contained in the biomass ash powder granules can be measured by well-known methods, such as wet quantitative analysis and calibration curve methods using X-ray fluorescence spectrometers.

[0017] The biomass ash granules are preferably granules with an amorphous content of 60% by mass or less.

[0018] As described above, the biomass ash powder particles have a D10 of 35 μm or more, and have a larger particle size than the cement used in the production of the cement kneaded body. When the proportion of the amorphous content in the biomass ash powder particles showing such a particle size increases, when a cement kneaded body is produced using this biomass powder particles, the reactivity with alkali metals (Na, K) increases and the amount of alkali silica gel generated increases, and due to the water absorption expansion accompanying this reaction, a phenomenon (alkali silica reaction) in which the durability decreases is likely to occur. By setting the proportion of the amorphous content in the biomass ash powder particles to 60% by mass or less, the reactivity with alkali metals decreases, and the alkali silica reaction is less likely to occur. The alkali silica reaction is also referred to as the "alkali aggregate reaction".

[0019] From the above viewpoints, the proportion of the amorphous content in the biomass ash powder particles is more preferably 50% by mass or less, still more preferably 40% by mass or less, and particularly preferably 30% by mass or less.

[0020] When measuring the proportion of the amorphous content in the biomass ash powder particles, for example, a method (XRD-Rietveld method) of calculating from the measurement results of X-ray diffraction by Rietveld analysis can be used.

[0021] The content rate of SO3 contained in the biomass ash powder particles is preferably 1% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less. When the content rate of SO3 contained in the biomass ash powder particles exceeds 1% by mass, when used in the production of the cement kneaded body, it may affect the quality of the cement hardened body, such as showing abnormal expansion.

[0022] The measurement method of the content rate of SO3 contained in the biomass ash powder particles can be measured by a well-known method. For example, wet quantitative analysis, a calibration curve using a fluorescent X-ray apparatus, etc. are preferably exemplified.

[0023] The loss on ignition of the biomass ash powder particles is preferably 3% by mass or less, particularly preferably 2% by mass or less. When the loss on ignition of the biomass ash powder particles exceeds 3% by mass, the amount of unburned carbon increases. When used in the production of a cement kneaded body, it adsorbs chemical admixtures added to the kneaded body, adversely affecting the fluidity and air content, or causing blackening in the obtained cement hardened body.

[0024] The method for measuring the loss on ignition of the biomass ash powder particles can be measured by a well-known method. For example, a method conforming to JIS R 5202 "Chemical Analysis Method of Cement" is preferably exemplified.

[0025] The cement kneaded body according to the present invention comprises cement and fine aggregate, characterized in that 5% to 40% by mass of the fine aggregate is composed of the biomass powder particles.

[0026] According to the above configuration, a cement kneaded body in which an increase in the chlorine content is suppressed while a part of the fine aggregate is replaced with biomass ash powder particles is realized.

[0027] However, the biomass ash powder particles are finer than the particle size of general fine aggregates defined in JIS A 5005 "Crushed Stone and Sand for Concrete". Therefore, when the biomass ash powder particles are mixed at a ratio exceeding 40% by mass of the total fine aggregate, the proportion of fine powder contained in the fine aggregate becomes too high, which may affect the fluidity of the cement kneaded body. On the other hand, when the biomass ash powder particles are mixed at a ratio less than 5% by mass of the total fine aggregate, the biomass ash, the generation amount of which tends to increase, cannot be fully utilized.

[0028] The method for producing the cement kneaded body according to the present invention comprises a step (a) of classifying biomass ash into coarse powder and fine powder, and a step (b) of mixing the coarse powder obtained in the step (a) with cement and water without pulverizing it.

[0029] The coarse powder classified in process (a) has a relatively large particle size compared to the fine powder of the biomass ash, resulting in a lower chlorine content. This makes it possible to keep the amount of chlorine in the resulting cement mixture within regulatory limits, even when used as a substitute material for fine aggregate in the production of cement mixtures.

[0030] This step (a) is preferably performed on biomass ash (preferably dry ash) in which no water has been added and the hydrate formation reaction has not progressed. For example, if the biomass ash is wet ash and has coagulated or formed hydrates, even after classification, the coarse powder may still contain a large amount of chlorine.

[0031] In this specification, "dry ash" refers to biomass ash that has been recovered in a dry state, to which no water has been added before classification, and which has not undergone coagulation or hydrate formation. Furthermore, even if water has been added to the dry ash before classification, it may be in a dispersed state due to the addition of a large amount of water, and hydrate formation may not have occurred due to long-term storage. In this specification, "wet ash" refers to, for example, bottom ash, which is the incineration residue discharged from the bottom of an incinerator, or fly ash collected by a dust collector, which has been recovered in a state containing moisture after being cooled or sprayed with water, or the dried version thereof. Generally, wet ash has a moisture content of 15% by mass or more.

[0032] When performing step (a) above, the apparatus is not particularly limited as long as it can classify the biomass ash at a classification point on the order of μm. For example, sieves, gravity sedimentation, inertial classifiers, centrifugal classifiers, gravity classifiers, etc., can be suitably used, and from the viewpoint of classification accuracy in particular, the use of cyclone-type air separators, vortex-type centrifugal classifiers, sieving devices, etc., is preferred. In this case, it is preferable to classify using a reference value in the range of 30 μm to 100 μm as the classification point.

[0033] Step (b) may also be a step in which the coarse powder and the adjusting powder are mixed together to adjust the mixture so that the proportion of amorphous material in the mixture of the coarse powder and the adjusting powder is 60% by mass or less, and then mixed with cement and water.

[0034] For example, if the amorphous content of the coarse powder obtained after classification exceeds 60% by mass, the amorphous content of the overall mixture can be reduced to 60% by mass or less by mixing in a lower amorphous content adjustment powder (such as other biomass ash). By using this mixture as a partial substitute material for fine aggregate, expansion due to alkali-silica reaction becomes less likely.

[0035] The method for producing the cement mixture further comprises a step (c) of washing the coarse powder obtained in step (a) with water, Step (b) may also be a step of mixing the coarse powder after it has been washed with water in step (c).

[0036] This further reduces the chlorine, alkali metal, and sulfur components contained in the coarse powder. It also reduces the amount of heavy metals such as selenium and chromium, which may cause environmental pollution, as well as highly reactive calcium oxide and calcium hydroxide.

[0037] The washing step (c) preferably includes the steps of adding water to the biomass ash to make a slurry (c1), supplying washing water to the slurry to wash it (c2), and dewatering the slurry after washing (c3). Since the dewatered product is obtained by washing the slurry and then dewatering it, chlorine and heavy metals can be removed.

[0038] The method for producing the cement mixture may further include a step (d) in which the biomass ash is oxidized during or after the execution of step (c).

[0039] This method adjusts the pH during washing to the acidic side, allowing for more efficient removal of chlorine. Furthermore, even if the biomass ash contains large amounts of highly reactive calcium oxide or calcium hydroxide, these can be completely replaced with calcium carbonate or calcium sulfate, thus homogenizing the fluidity and other qualities of the cement mixture before hardening.

[0040] Step (d) may involve adding an acid solution during the washing of the biomass ash, blowing in a carbon dioxide (CO2)-containing gas, or blowing in a CO2-containing gas onto the biomass ash after washing. In particular, by using combustion exhaust gas from cement kilns, extraction gas from chlorine bypasses, or combustion exhaust gas from biomass incineration facilities or biomass power plants as the CO2-containing gas, the CO2 contained in these gases can be converted into calcium carbonate and fixed in the biomass ash, thus offering the potential to reduce CO2 emissions. In addition, sulfur oxides (SO2) contained in the exhaust gas can also be used. x Harmful gases such as those mentioned above can also be converted into calcium sulfate and immobilized in biomass ash.

[0041] Furthermore, in particular, in step (d), by carbonizing the biomass ash during the washing process in step (c), the calcium content in the wastewater after washing can be precipitated as calcium carbonate, thereby suppressing scale formation. This helps to prevent blockage of pipes and other equipment used for wastewater treatment.

[0042] The method for producing the cement mixture may further include a step (e) to remove unburned carbon contained in the biomass ash during the execution of step (c).

[0043] Biomass ash (raw ash) may contain a large amount of unburned carbon. Therefore, when biomass ash containing a large amount of carbon is used as a substitute material for fine aggregate, the resulting cement hardened product may become discolored, or chemical admixtures may be adsorbed onto the carbon, potentially reducing the fluidity of the cement mixture before hardening or decreasing the air content.

[0044] In contrast, the above method allows for the removal of unburned carbon during washing, thereby suppressing the occurrence of the aforementioned problems. Specifically, the amount of unburned carbon can be reduced by mixing in an unburned carbon removal agent such as oil or a surfactant and performing flotation.

[0045] Furthermore, the cement mixture and method for producing cement according to the present invention include the method for producing the cement mixture described above. The present invention is characterized by having a step (f1) in which the fine powder obtained in step (a) is added to at least one of the following: cement clinker raw material to be fed into a cement kiln, cement clinker obtained from the cement kiln, or cement obtained after grinding treatment of the cement clinker.

[0046] Biomass ash has low reactivity, but the finer the particle size, the higher the reactivity and alkali metal content. Therefore, as described above, when the fine powder obtained after classifying biomass ash is mixed with cement clinker raw materials, cement clinker (hereinafter, both may be collectively referred to as "cement raw materials"), or cement, the reaction is activated. Consequently, the strength of the hardened cement is increased compared to when unclassified biomass ash is added to cement raw materials or cement.

[0047] In other words, according to the above method, coarse powder with a relatively low chlorine content is used as a partial substitute material for fine aggregate, and fine powder with a relatively high chlorine content is used as a partial substitute material for cement raw materials and cement admixtures. This allows for the effective use of biomass ash without any waste.

[0048] When finely ground biomass ash, after classification, is added during cement production, cement with a high alkali metal content may be produced. When this cement is mixed with aggregate to produce cementitious concrete, there is a risk of alkali-silica reaction occurring. To counteract this, the alkali-silica reaction can be suppressed by adding latent hydraulic materials such as blast furnace slag or pozzolans (including natural pozzolans such as silica powder and stone powder, and artificial pozzolans such as fly ash and calcined clay) together with the finely ground ash.

[0049] If the proportion of amorphous material in the biomass ash powder granules (coarse powder) exceeds 60% by mass, or if the replacement rate of biomass ash powder granules for fine aggregate exceeds 40% by mass, then, similarly, from the viewpoint of suppressing alkali-silica reaction, at least one of the latent hydraulic substance and pozzolanes may be mixed as an admixture in step (b) above.

[0050] The method for producing the cement mixture and cement includes a step (c) of washing the biomass ash with water before or after performing step (a), The aforementioned step (f1) may also be a step of adding the fine powder after it has been washed with water in step (c).

[0051] According to the inventors' research, when comparing the coarse and fine powders obtained after classifying biomass ash, it was confirmed that most of the chlorine contained in the biomass ash is contained in the fine powder. Therefore, since chlorine, a cement-repellent component, is efficiently removed from the biomass ash after washing, using it as a cement raw material or added to cement can suppress the corrosion of reinforcing steel in concrete.

[0052] The method for producing the cementite and cement includes a step (g) of grinding the coarse powder obtained in step (a) in which the proportion of amorphous material exceeds 60% by mass, The method may also include a step (f2) in which the coarse powder crushed in step (g) is added to at least one of the cement clinker raw material, the cement clinker, or the cement obtained after the crushing treatment of the cement clinker.

[0053] If the proportion of amorphous material in the coarse powder obtained after classification of biomass ash is high, exceeding 60% by mass, using this coarse powder as a partial substitute for fine aggregate may cause alkali-silica reaction. On the other hand, the coarse powder obtained after classification of biomass ash has low calcium, sulfur, chlorine, and carbon content, and its composition is close to that of coal ash. Therefore, when used as a raw material for cement clinker, homogeneity can be ensured compared to conventional clinker raw materials. In particular, because of the low sulfur and chlorine content, coating is less likely to occur in the cement kiln, and the load on the chlorine bypass is less likely to increase. Furthermore, even when used as an admixture, it has low sulfur, chlorine, and carbon content, which affect the quality of concrete, and can be used as a cement admixture or concrete admixture with increased reactivity due to pulverization.

[0054] Specific methods for the aforementioned steps (f1) and (f2) include feeding the raw materials into raw material mixing equipment such as mixers and crushers for mixing the raw materials of cement clinker, feeding the raw materials into the preheater top or calcination furnace in front of the cement kiln (rotary kiln), feeding the raw materials into the end of the cement kiln, feeding the raw materials into the front of the cement kiln, feeding the cement clinker obtained by firing into a clinker cooler, feeding the cement clinker into a crushing device (mill) for crushing the cement clinker, feeding the raw materials into a mixer for manufacturing mixed cement, and feeding the raw materials into a concrete mixer.

[0055] Furthermore, if the proportion of amorphous material in the coarse powder exceeds 60% by mass, the coarse powder may be added to the cement clinker raw material without being crushed. [Effects of the Invention]

[0056] According to the present invention, it is possible to effectively utilize biomass ash while suppressing the increase in chlorine content of cement-hardened materials such as concrete. [Brief explanation of the drawing]

[0057] [Figure 1] This diagram schematically shows the processing flow of the first embodiment of the cement mixture and cement manufacturing method. [Figure 2] This block diagram schematically shows the configuration of the manufacturing system that implements the processing flow shown in Figure 1. [Figure 3] This graph shows the particle size distribution of incinerated fly ash obtained from biomass power generation facility P1, which was used in Verification 1. [Figure 4] This diagram schematically shows the processing flow of the second embodiment of the cement mixture and cement manufacturing method. [Figure 5] This diagram schematically shows an example of a detailed processing flow for the washing process. [Figure 6] This block diagram schematically shows the configuration of the manufacturing system that implements the processing flow shown in Figure 4. [Figure 7] This is a block diagram schematically showing an example of the structure of a flushing system in Figure 6. [Figure 8] Figure 4 is a schematic diagram illustrating an example of a processing flow when the oxidation process and the unburned carbon removal process are performed together with the washing process in the manufacturing method shown. [Figure 9] This block diagram schematically shows another example of the structure of the flushing equipment shown in Figure 6. [Figure 10] This diagram schematically shows another processing flow of a second embodiment of the cement mixture and cement manufacturing method. [Figure 11] Figure 10 is a block diagram schematically showing the configuration of a manufacturing system that implements the processing flow shown. [Figure 12] Figure 10 is a schematic diagram illustrating an example of a processing flow when the oxidation process and the unburned carbon removal process are performed together with the washing process in the manufacturing method shown. [Figure 13] This block diagram schematically shows another configuration of the manufacturing system that implements the processing flow shown in Figure 10. [Figure 14] This diagram schematically shows the processing flow of the third embodiment of the cement mixture and cement manufacturing method. [Figure 15]This block diagram schematically shows the configuration of the manufacturing system that implements the processing flow shown in Figure 14. [Figure 16] This is a polarized light microscope image of biomass ash. [Modes for carrying out the invention]

[0058] [First Embodiment] A first embodiment of the cement mixture and cement manufacturing method according to the present invention will be described. The biomass ash powder granules envisioned in the present invention will also be described in this section.

[0059] Figure 1 is a schematic diagram showing the processing flow of the first embodiment of the cement mixture and cement manufacturing method. Figure 2 is a schematic block diagram showing the structure of the system for implementing this manufacturing method.

[0060] The manufacturing system 1 shown in Figure 2 comprises a raw material tank 3 in which cement clinker raw material Y1 is stored, a powder storage tank 5 in which biomass ash B1 is stored, clinker manufacturing equipment 10, classification equipment 20, crushing equipment 31, and mixing equipment 33.

[0061] The biomass ash B1 to which this invention applies broadly includes biomass incineration ash, such as incineration ash of plants and bamboo, and incineration ash of food waste. Biomass ash contains water-soluble alkali metal chlorides, alkali metal sulfates, and alkali metal carbonates. Compared to municipal solid waste incineration ash and chlorine bypass dust, biomass ash has the advantage of having a higher proportion of alkali metal sulfates and alkali metal carbonates and a lower concentration of alkali chlorine.

[0062] In this embodiment, it is assumed that after the biomass ash B1 is classified, it will be added to the cement Cn2 manufacturing process (including the cement clinker Cn1 manufacturing process) or to the cement mixture Cn3 manufacturing process, as described later.

[0063] The K2O content of biomass ash B1 is preferably 2% to 10% by mass, more preferably 3% to 8% by mass, and even more preferably 3% to 5% by mass. If the K2O content of the biomass ash is less than 2% by mass, the strength of the cement when used as an admixture may be reduced, and it may not be possible to secure the necessary amount of K2O as an additive to the cement. On the other hand, if the K2O content of the biomass ash exceeds 10% by mass, the amount that can be used when used as a raw material for cement clinker may be limited, and the occurrence of alkali-silica reaction when used as an admixture may increase.

[0064] The total alkali concentration in biomass ash B1 is preferably 2% to 11% by mass, and more preferably 3% to 6% by mass, when converted to R2O (R2O = Na2O + 0.658 × K2O). Furthermore, the sulfur oxide (SO3) concentration in the biomass ash is preferably 0.5% to 6% by mass, and more preferably 1% to 5% by mass.

[0065] Biomass power plants sometimes co-fire biomass and coal, and the biomass ash B1 to which this invention applies includes ash produced when such co-firing is performed. However, coal ash obtained by burning coal generally has a low K2O content, so the activity of the biomass ash differs depending on the amount of coal used during co-firing. For this reason, in the case of co-firing with coal, it is preferable that the ash be obtained from fuel in which biomass accounts for 50% by mass or more.

[0066] As a suitable example of biomass ash B1, palm kernel shell ash (PKS ash), obtained from the incineration of grass, trees, and bamboo using palm kernel shells as fuel, is also cited. Palm kernel shells are a by-product of palm oil production and are mainly used in the natural biomass energy industry. Palm kernel shells are a yellowish-brown fibrous material with a low ash content, a particle size of about 5 mm to 40 mm, and a calorific value of about 4000 kcal / kg. In recent years, palm kernel shells have been increasingly used as fuel for biomass power generation in energy production using renewable resources.

[0067] Generally, biomass power generation furnaces include stoker-type and fluidized-bed types. In fluidized-bed furnaces, such as circulating fluidized-bed and pressurized fluidized-bed furnaces, limestone is added to perform desulfurization within the furnace. Biomass ash from such furnaces contains high levels of calcium and sulfur, with the CaO content generally ranging from 5% to 45% by mass. The Ca compounds derived from the added limestone include forms such as CaO (quicklime), Ca(OH)2 (slaked lime), CaCO3 (calcium carbonate), and CaSO4 (gypsum). Sand is also added as a fluidizing medium, and minerals derived from the added sand include quartz and feldspar.

[0068] Biomass ash B1 may be bottom ash remaining at the bottom of a combustion furnace in a biomass power plant, or it may be fly ash obtained by collecting soot and dust suspended as gas in the combustion exhaust gas using a dust collector while it is still dry. Of these, fly ash is preferred because it has a higher concentration of alkali metals and chlorine, and chlorine is easily separated by classification and washing, making it efficient.

[0069] Furthermore, the biomass ash B1 is preferably dry ash. Biomass ash that has been sprayed with water once may become granular, or chlorine may be incorporated into the resulting hydrate, making it difficult to separate the chlorine by classification or washing. As for the dry ash, it is preferable that, for example, Friedel's salt or ettringite, which are hydrates, are not detected by powder X-ray diffraction. Alternatively, the moisture content is preferably 10% by mass or less, and more preferably 5% by mass or less. Alternatively, the ignition loss is preferably 10% or less. The moisture content can be determined as the mass loss rate when dried at 105°C. The ignition loss can be determined as the mass loss rate when the object dried at 105°C is heated at 975°C.

[0070] From the viewpoint of increasing the strength of the cement mixture, biomass ash B1 preferably has a median particle size (D50) of 200 μm or less, more preferably 150 μm or less, and even more preferably 90 μm or less. Particle size can be measured using a laser diffraction / scattering particle size distribution analyzer, for example, by using a Microtrac-Bell MW3300EXII with ethanol as the dispersion medium and measuring after ultrasonic dispersion for 1 minute. Note that D50 means the value of the cumulative volume percentage of the particle size distribution at 50%.

[0071] The clinker manufacturing equipment 10 is a facility that produces cement clinker Cn1 by firing cement clinker raw material Y1, and comprises a cement kiln 12 for firing, a preheater 11 for preheating the cement clinker raw material Y1 before putting it into the cement kiln 12, and a clinker cooler 13 for cooling the cement clinker Cn1 after firing.

[0072] The crushing equipment 31 is a device that crushes cement clinker Cn1 together with gypsum or the like as needed to produce fine-grained cement Cn2, and can use a general mill used in finishing processes such as a tube mill.

[0073] The mixing equipment 33 is a device that mixes cement Cn2, water W1, fine aggregate FA, and coarse aggregate CA to produce a cement mixture Cn3, and is composed of a known mixer. The mixing equipment 33 is installed, for example, in a concrete plant. Here, the cement mixture Cn3 is concrete.

[0074] As shown in Figure 1, the manufacturing method of this embodiment includes a step S10 for classifying biomass ash B1, a step S20 for adding the classified coarse powder B1C to the manufacturing process of cement mixture Cn3, and a step S30 for adding the classified fine powder B1F to the manufacturing process of cement Cn2. Hereafter, the adding or supplementing steps will be collectively referred to as the "adding" steps.

[0075] (Classification process S10) The biomass ash B1 stored in the powder storage tank 5 is classified by the classification equipment 20 into coarse powder B1C with a coarse particle size and fine powder B1F with a fine particle size, based on a predetermined classification point.

[0076] The classification point determined in classification step S10 is preferably in the range of 30 μm to 100 μm, more preferably in the range of 30 μm to 90 μm, and particularly preferably in the range of 38 μm to 75 μm.

[0077] The classification equipment 20 is not particularly limited as long as it is capable of classifying the biomass ash B1 at classification points on the order of μm as described above. For example, sieves, gravity sedimentation, inertial classifiers, centrifugal classifiers, gravity classifiers, etc., can be suitably used, and from the viewpoint of classification accuracy in particular, the use of cyclone-type air separators, vortex-type centrifugal classifiers, sieving devices, etc. is preferred. In addition, as will be described later in the second embodiment, if a washing process S40 is performed, wet classification is efficient.

[0078] Fluidized bed incinerators use sand, primarily composed of quartz, as a fluidizing medium, along with limestone for desulfurization. The fly ash from such incinerators contains relatively coarse-grained melted and solidified or aggregated glass and sand-derived materials, as well as relatively fine-grained volatile alkali metal salts, the aforementioned limestone-derived materials, and fine glass particles. Therefore, by defining the classification point as the point between the peaks on the fine-grained and coarse-grained sides when the particle size distribution of the biomass ash is expressed by frequency, chlorine, sulfur, and calcium can be efficiently separated.

[0079] Figure 3 is a graph showing the particle size distribution of incinerated fly ash obtained from biomass power generation facility P1, which will be used in Verification 1 described later. According to the graph in Figure 3, it can be seen that there are peaks with high frequency values ​​on the fine powder side and the coarse powder side, respectively. The fine powder side is thought to be derived from lime and alkali metal salts, while the coarse powder side is thought to be derived from quartz and feldspar. Therefore, it can be seen that chlorine, sulfur, and calcium can be efficiently separated by classifying the particle size in the region between these peaks (the valley region) as the classification point. Fluidized bed incinerators may be equipped with equipment to recover incinerated ash that has settled in the boiler, air preheater, and high-temperature gas flow path, as well as equipment to recover incinerated ash such as cyclones and bag filters. Since the particle sizes of the incinerated ash recovered by these recovery facilities differ, they can be separated and recovered to replace the classification device.

[0080] The classification equipment 20 may be equipped with a storage tank for biomass ash B1. Furthermore, it may be equipped with a supply device for quantitatively supplying biomass ash B1 from this storage tank to the classification equipment 20. These storage tanks and supply devices may be used as appropriate depending on the condition of the received biomass ash B1.

[0081] The primary guideline for classification in the classification process S10 is the particle size of the coarse powder B1C obtained after classification. Specifically, the coarse powder B1C obtained after classification is classified in the classification process S10 so that its D10 value is 35 μm or more. More preferably, the D10 value of the coarse powder B1C after classification is 50 μm to 115 μm.

[0082] The median particle size (D50) of coarse powder B1C is preferably 100 μm to 300 μm, more preferably 150 μm to 250 μm, and particularly preferably 175 μm to 200 μm. The D90 particle size of coarse powder B1C is preferably 80 μm to 400 μm.

[0083] According to the coarse powder B1C exhibiting the above particle size distribution, the chlorine (Cl) content is typically reduced to 0.2% by mass or less. Preferably, the chlorine content of coarse powder B1C is 0.01% by mass to 0.1% by mass, and more preferably 0.01% by mass to 0.05% by mass.

[0084] Furthermore, the chlorine concentration ratio (ratio of chlorine content) of fine powder B1F to coarse powder B1C is preferably 4 or higher, more preferably 8 or higher, and even more preferably 12 or higher. The chlorine content of fine powder B1F is typically, for example, 0.2% to 2% by mass, and more typically 0.3% to 1.5% by mass. In other words, this classification process S10 separates the biomass ash B1 (raw ash) into coarse powder B1C, which has a relatively low chlorine content, and fine powder B1F, which has a relatively high chlorine content.

[0085] Other criteria for classification in classification process S10 include amorphous content, activity index, yield, sulfur oxide (SO3) concentration, calcium oxide (CaO) concentration, and loss on ignition.

[0086] The coarse powder B1C obtained after classification typically has an amorphous content of 60% by mass or less. The amorphous content of coarse powder B1C is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less. The amorphous content of fine powder B1F is typically 50% by mass to 80% by mass, and more typically 60% by mass to 70% by mass. In other words, this classification step S10 separates the coarse powder B1C, which has a relatively low amorphous content, from the fine powder B1F, which has a relatively high amorphous content. This point will be described later with reference to the examples.

[0087] The activity index of the fine powder B1F obtained in classification process S10 is higher than that of biomass ash (raw ash) B1, typically reaching over 70% after 7 days and over 65% after 28 days, and more typically over 75% after 7 days and over 70% after 28 days. The activity index contained in biomass ash B1 (B1C, B1F) can be measured by well-known methods, and a preferred example is the method conforming to JIS A 6201:2015 "Fly ash for concrete".

[0088] The yield of fine powder B1F is preferably 10% to 80% by mass, more preferably 20% to 70% by mass, and even more preferably 30% to 60% by mass. The yield of fine powder B1F may be the ratio of the total mass of the obtained fine powder B1F to the total mass of biomass ash B1 before the classification process S10. On the other hand, the yield of coarse powder B1C is preferably 20% to 90% by mass, more preferably 30% to 80% by mass, and even more preferably 40% to 70% by mass.

[0089] The ratio of total alkali concentration of fine powder B1F to coarse powder B1C is preferably 1.05 or higher, more preferably 1.1 or higher, and even more preferably 1.2 or higher, in terms of R2O (R2O = Na2O + 0.658 × K2O). The total alkali concentration of fine powder B1F is typically 2% to 10% by mass, and more typically 3% to 8% by mass. On the other hand, the total alkali concentration of coarse powder B1C is typically reduced to 0.5% to 6% by mass, and more typically to 2% to 5% by mass. The total alkali concentration contained in biomass ash B1 (B1C, B1F) can be measured by well-known methods, such as wet quantitative analysis and calibration curves using X-ray fluorescence spectrometers. Similar methods can be used to measure the concentrations of chlorine, sulfur oxides, calcium oxide, etc.

[0090] The ratio of sulfur oxide (SO3) content in fine powder B1F to coarse powder B1C is preferably 5 or more, more preferably 10 or more, and even more preferably 20 or more. The sulfur oxide content of fine powder B1F is typically, for example, 1% to 6% by mass, and more typically 2% to 5% by mass. On the other hand, the sulfur oxide content of coarse powder B1C is typically reduced to 1% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.2% by mass or less.

[0091] The calcium oxide concentration ratio of fine powder B1F to coarse powder B1C is preferably 1.5 or higher, more preferably 2 or higher, and even more preferably 3 or higher. The calcium oxide concentration of fine powder B1F is typically 8% to 40% by mass, and more typically 15% to 35% by mass. On the other hand, the calcium oxide concentration of coarse powder B1C is typically reduced to 3% to 15% by mass, and more typically to 5% to 10% by mass.

[0092] The ignition loss of coarse powder B1C is preferably 3% by mass or less, and particularly preferably 2% by mass or less. On the other hand, the ignition loss of fine powder B1F is typically 5% to 15% by mass, and more typically 5% to 10% by mass. In other words, this classification process S10 separates the coarse powder B1C, which has a relatively low ignition loss, from the fine powder B1F, which has a relatively high ignition loss. The ignition loss of biomass ash B1 (B1C, B1F) can be measured by a well-known method, and for example, a method conforming to JIS R 5202 "Method for Chemical Analysis of Cement" is a preferred example.

[0093] This classification process S10 corresponds to process (a), and the coarse powder B1C obtained in this classification process S10 corresponds to "biomass ash powder granules".

[0094] (Input process S20: During cement mixture production) The coarse powder B1C obtained in the classification process S10 is added as a partial substitute material for the fine aggregate FA during the production of cement mixtures such as concrete Cn3. In the example in Figure 2, the coarse powder B1C is mixed together with cement Cn2, water W1, fine aggregate FA, and coarse aggregate CA in the mixing equipment 33. As described above, a general mixer is used as the mixing equipment 33.

[0095] In the production of cement mixture Cn3, the substitution rate of coarse powder B1C for fine aggregate FA is preferably 5% to 40% by mass, more preferably 10% to 30% by mass, and particularly preferably 15% to 25% by mass.

[0096] As described above, the coarse powder B1C separated from the biomass ash (raw ash) B1 in the classification process S10 has a low chlorine content. Therefore, even when mixed with cement Cn2 as a partial substitute material for the fine aggregate FA during the production of cement mixture Cn3, the amount of chlorine contained in the cement mixture Cn3 can be kept within the regulatory limit.

[0097] As described above, the coarse powder B1C separated from the biomass ash (raw ash) B1 in the classification process S10 has a relatively low amorphous content. Therefore, when mixed with cement Cn2 as a partial substitute material for the fine aggregate FA during the production of cement compound Cn3, expansion due to alkali-silica reaction is less likely to occur.

[0098] As described above, the coarse powder B1C separated from the biomass ash (raw ash) B1 in the classification process S10 has a relatively low sulfur oxide content. Therefore, even when mixed with cement Cn2 as a partial substitute material for the fine aggregate FA during the production of cement mixture Cn3, the setting of the cement mixture Cn3 is not accelerated beyond the desired state, and the quality of the hardened cement can be homogenized.

[0099] As described above, the coarse powder B1C separated from the biomass ash (raw ash) B1 in the classification process S10 has a relatively low loss on ignition and a small amount of unburned carbon. Therefore, even if it is mixed with cement Cn2 as a partial substitute material for the fine aggregate FA during the production of cement mixture Cn3, there is a low possibility that the resulting hardened cement product will darken.

[0100] The input step S20 in the manufacturing process of the cement mixture Cn3, as described above, corresponds to step (b).

[0101] (Input process S30: During cement manufacturing) The fine powder B1F obtained in the classification process S10 is added to the raw material for cement clinker Cn1, or to cement clinker Cn1 or cement Cn2. In the example in Figure 2, the cases in which the fine powder B1F is added to the clinker manufacturing equipment 10 and to the crushing equipment 31 for producing cement Cn2 are illustrated. In the latter case, the fine powder B1F is crushed together with the cement clinker Cn1 to produce mixed cement. At that time, water or crushing aids are added as needed. However, the fine powder B1F may be added to either the clinker manufacturing equipment 10 or the crushing equipment 31. However, adding all of the obtained fine powder B1F is equivalent to adding the raw biomass ash powder (raw ash B1) as is. Therefore, taking advantage of the fact that the properties such as the chemical composition of the classified biomass ash (i.e., coarse powder B1C and fine powder B1F) are different, fine powder B1F may be partially added to the raw material for cement clinker Cn1, cement mix, or concrete admixture, or added after being washed with water as described later.

[0102] As the grinding equipment 31, a general mill used in finishing processes such as a tube mill can be used. A mill, also called a finishing grinder, grinds steel balls, cement clinker Cn1, and gypsum (added as needed) in a cylindrical drum, as they collide with each other due to the rotation of the drum. When using gypsum, the type of gypsum is not particularly limited, and examples include natural dihydrate gypsum, flue gas desulfurization gypsum, phosphate gypsum, titanium gypsum, hydrofluoric acid gypsum, etc. These may be used individually or in combination of two or more types.

[0103] Fine powder B1F is used to replace a portion of the cement raw materials. When introduced into the crushing equipment 31, it is preferable to add 0.5% to 30% by mass relative to the mass of cement clinker Cn1. In addition, it is preferable to add gypsum in an amount of 1.5% to 5.0% by mass in terms of SO3 to improve the strength development and fluidity of cement Cn2.

[0104] Alternatively, the fine powder B1F obtained in the classification process S10 may be directly introduced into the clinker cooler 13. One method of introduction is to drop the powder from the top of the clinker cooler 13 to a desired temperature within the cooler. The amount introduced is preferably set to approximately 0.5% to 20% by mass relative to the mass of cement clinker Cn1. It is preferable to use an air quenching cooler as the clinker cooler 13, as this allows the fine powder B1F to be introduced to a predetermined position within the clinker cooler 13.

[0105] As will be described later in the second embodiment, when the fine powder B1F is added after being washed with water, it is advantageous to add it to the clinker cooler 13 so that the moisture can be evaporated and removed using thermal energy that is not directly related to the production of cement clinker Cn1. In addition, in order to prevent the generation of a large amount of dust inside the clinker cooler 13, it is preferable that the moisture content of the fine powder B1F be 50% by mass or less and that it be added in lump form or granular form.

[0106] Although not shown in Figure 2, fine powder B1F may be added to the cement Cn2 obtained by crushing in the crushing equipment 31. Specifically, the timing of this addition may be along the path to the cement silo where the cement is stored downstream of the crushing equipment 31, or it may be inside the cement silo. However, more precisely, it is preferable to add the fine powder B1F to the cement clinker Cn1 or the crushing equipment 31 rather than mixing it with the cement Cn2 obtained after the cement clinker Cn1 has been crushed in the crushing equipment 31, as this results in a finer particle size and higher reactivity.

[0107] As mentioned above, the input process S30 in the manufacturing process of cement Cn2 corresponds to process (f1).

[0108] [Second Embodiment] A second embodiment of the cement mixture and cement manufacturing method will be described, focusing on the differences from the first embodiment. Figure 4 is a schematic diagram showing the processing flow of the manufacturing method in this embodiment. Figure 5 is a schematic diagram showing an example of a detailed processing flow of the washing process S40, which will be described later. Figure 6 is a schematic block diagram showing the manufacturing system 1 that implements the manufacturing method of this embodiment, following Figure 2.

[0109] The manufacturing system 1 of this embodiment, shown in Figure 6, differs from the first embodiment in that it includes a washing facility 40. The washing facility 40 is a facility for washing biomass ash B1 with water and is provided for the purpose of reducing the concentration of cement-repellent components such as chlorine contained in the biomass ash B1. An example of the detailed structure of the washing facility 40 will be described later with reference to Figure 7.

[0110] In the processing flow shown in Figure 4, the washing process S40 is performed only on the fine powder B1F obtained after the classification process S10. This is because, as described above in the first embodiment, the classification process S10 reduces the chlorine content of the coarse powder B1C, while the chlorine content of the fine powder B1F remains relatively high. However, as will be discussed later, the washing process S40 may also be performed on the coarse powder B1C, or the washing process S40 may be performed together with the classification process S10.

[0111] (Water washing process S40) In this embodiment, the fine powder B1F obtained by classifying the biomass ash (raw ash) B1 in the classification process S10 is subjected to a water washing treatment using the water washing equipment 40. More specifically, as shown in Figure 5, the fine powder B1F is subjected to a slurrying process S41, a water washing process S42, and a dewatering process S43.

[0112] As an example, the washing equipment 40 shown in Figure 7 includes a powder dissolution tank 43 for adding water W2 to the fine powder B1F obtained after classification to make a slurry Lr1 for washing, a solid-liquid separation device 46 for dewatering the slurry Lr2 discharged from the powder dissolution tank 43 after washing, and a conveying device 47 for transporting the dewatered material Ck1 separated by the solid-liquid separation device 46.

[0113] Furthermore, in the example of the washing equipment 40 shown in Figure 7, a liquid supply device 42 for supplying water W2 is provided. In addition, a slurry stirring device 44 equipped with stirring blades is provided for mixing the fine powder B1F and water W2, and for stirring the slurry Lr1 produced by the mixing.

[0114] In the powder dissolution tank 43, a slurrying step S41 is performed in which fine powder B1F and water W2 are mixed and stirred to produce slurry Lr1, and a washing step S42 is performed in which cement-repellent components such as chlorine are dissolved into the liquid phase in the slurry Lr1. For the slurry stirring device 44, for example, a general stirring device of the paddle type or screw type can be used.

[0115] In the slurrying step S41, the mass ratio (W2 / B1F) of fine powder B1F to water W2 is preferably 2 to 10, more preferably 3 to 7, and particularly preferably 4 to 5. If the mass ratio (W2 / B1F) is less than 2, the elution of water-soluble components such as chlorine from the fine powder B1F may be insufficient, resulting in an insufficient modification effect. Also, if the mass ratio (W2 / B1F) is greater than 10, the amount of wastewater W4 will increase.

[0116] The washing step S42 is performed by letting the slurry Lr1 stand or stirring it for a predetermined time. This yields slurry Lr2 in which the soluble components of the fine powder B1F have dissolved into the liquid phase of the slurry.

[0117] The time required for the water washing step S42 is preferably 30 minutes or more, and more preferably 45 minutes or more, in order to sufficiently modify the fine powder B1F with water W2. The higher the temperature during the water washing step S42, the better the elution efficiency of water-soluble components such as chlorine from the fine powder B1F. However, from the viewpoint of the cost of the treatment, the temperature is preferably 5°C to 50°C, and more preferably 25°C to 50°C.

[0118] After the washing process S42, the slurry Lr2, in which cement-repellent components such as chlorine have been dissolved into the liquid phase, is discharged from the powder dissolution tank 43 and transferred to the solid-liquid separation device 46. For the transfer of slurry Lr2, a standard slurry liquid transport device (not shown), such as a slurry centrifugal pump, piston pump, or mono pump, may be used.

[0119] The solid-liquid separation device 46 separates the slurry Lr2 into solid and liquid components to obtain dehydrated material Ck1 (dehydration step S43). As the solid-liquid separation device 46, conventional filtration devices such as a filter press, pressurized foliar filter, screw press, belt press, belt filter, and sedimentation separator can be used.

[0120] In the dewatering step S43, in order to prevent water-soluble components such as chlorine contained in the slurry Lr2 from remaining with the liquid phase, the moisture content of the dewatered product is preferably 20% to 90% by mass, and more preferably 30% to 70% by mass.

[0121] Since the components dissolved in the liquid phase of slurry Lr2 are removed into wastewater W4, the resulting dewatered product Ck1 has a lower amount of cement-repellent components such as chlorine compared to the fine powder B1F before the washing process S40. On the other hand, since heavy metals and other substances contained in biomass ash B1 are also dissolved in wastewater W4, it may be discharged into the environment after appropriate water purification treatment.

[0122] Alternatively, as shown in Figure 7, a water washing device 49 may be attached to the solid-liquid separation device 46, and water W3 may be added to the dewatered material Ck1 before dewatering again. In this case, the liquid phase of the slurry Lr2 is almost entirely replaced with water, so the eluted components can be removed more reliably.

[0123] This rinsing process S40 corresponds to process (c).

[0124] The dehydrated product Ck1 obtained through the washing process S40 has reduced cement-repellent components such as chlorine, and the content of easily reactive calcium oxide and calcium hydroxide, which affect the strength development and fluidity of cement Cn2, is sufficiently reduced. Therefore, by using this dehydrated product Ck1 derived from fine powder B1F and adding it to the raw material for cement clinker Cn1, or to cement clinker Cn1 or cement Cn2, as in the first embodiment, it becomes easy to maintain the homogeneity of the resulting cement Cn2. In particular, when biomass ash B1 discharged from a fluidized bed combustion furnace into which limestone containing calcium components is added is used as the raw ash, the above effect can be realized in a particularly significant way.

[0125] Furthermore, the dehydrated product Ck1 derived from the fine powder B1F obtained through the washing process S40 may contain more moisture than the fine powder B1F obtained in the first embodiment. Therefore, by introducing this dehydrated product Ck1 into the grinding equipment 31, it can also be used for temperature control within the grinding equipment 31. If the moisture content of the dehydrated product Ck1 is excessive, it can be easily dehydrated by sedimentation separation, etc., and conversely, if there is insufficient moisture, an appropriate amount of water can be sprinkled into the grinding equipment 31.

[0126] The wastewater W4 obtained in the dewatering step S43 may be mixed with the cement clinker Cn1 after reducing the chloride ions contained by well-known methods such as ion exchange resin, membrane separation, or precipitation formation with silver or lead ions. This allows for the effective utilization of alkali metals that exhibit strength-enhancing effects contained in the wastewater W4 while removing chlorine that causes rebar corrosion. As in this embodiment, the dewatered product Ck1 derived from the fine powder B1F obtained by performing the washing step S40 has reduced activity due to washing, so the decrease in activity can be compensated for by adding the washed wastewater W4 as a cement additive.

[0127] Biomass ash B1 has a lower chlorine content than municipal solid waste incineration ash. Therefore, chlorine in wastewater W4 can be easily separated, and wastewater W4 yields a large amount of alkali metal sulfates and carbonates. For this reason, by introducing wastewater W4 along the path from the clinker cooler 13 to the crushing equipment 31, more alkali metals can be utilized as cement additives.

[0128] By introducing wastewater W4 along the path from the clinker cooler 13 to the crushing equipment 31, it can serve the dual purpose of cooling the cement clinker Cn1 and regulating the temperature inside the crushing equipment 31 without drying or solidifying. More specifically, potential input points include the clinker cooler 13, which is below 400°C, the conveying equipment for transporting the clinker from the clinker cooler 13 to the downstream stage, and the crushing equipment 31 in the clinker manufacturing facility 10. If the temperature at the input point exceeds 400°C, it will evaporate instantly, making it difficult for alkali metals as cement additives to be incorporated into the cement Cn2. Furthermore, if wastewater W4 is introduced downstream of the crushing equipment 31, moisture will remain in the cement Cn2, potentially leading to a decline in quality due to weathering and hydration.

[0129] The wastewater W4 may be subjected to drying treatment or other processes to reduce its moisture content before being introduced between the clinker cooler 13 and the crushing equipment 31. This allows for the utilization of more alkali metals as cement additives without causing weathering of the cement Cn2. In particular, drying and solidifying the wastewater W4 makes it possible to add it to the cement Cn2 obtained after crushing in the crushing equipment 31, or to the mixing process carried out in the mixing equipment 33, allowing for easy addition of any desired amount.

[0130] As a means of reducing the chloride ion content, methods using amphoteric ion exchange resins or nanofiltration membranes are particularly preferred. This allows for the selective separation of sulfate ions, carbonate ions, and chloride ions, making it possible to obtain water with high sulfate and carbonate ion concentrations and low chloride ion concentrations, and water with low sulfate and carbonate ion concentrations and high chloride ion concentrations.

[0131] The wastewater W4 obtained after washing the fine powder B1F often contains selenium and hexavalent chromium. By using the amphoteric ion exchange resin or nanofiltration membrane mentioned above, selenium and hexavalent chromium, which exhibit a similar morphology to sulfate ions, are separated into the water with a lower chlorine concentration. The water with a high chlorine concentration is disposed of, but this water also has low concentrations of selenium and hexavalent chromium, making wastewater treatment easier. Furthermore, the water volume can be reduced without drying (increasing the alkali metal concentration), and when introduced between the clinker cooler 13 and the crushing equipment 31, more alkali metals can be utilized as cement additives with the same amount of water sprayed.

[0132] As described above, both the wastewater W4 (cement additive) obtained from the washing water and the dewatered material Ck1 obtained after washing the fine powder B1F can be used in the manufacturing process of cement Cn2. Furthermore, as described above in the first embodiment, the coarse powder B1C can be used as a partial substitute material for the fine aggregate FA when manufacturing cement mixture Cn3. This allows biomass ash B1 to be used without waste in the manufacturing of cement Cn2 and cement mixture Cn3. In addition, it can be expected to reduce the amount of wastewater to be disposed of and the burden on wastewater treatment.

[0133] In this embodiment, it is also possible to perform the oxidation process S51 and the unburned carbon removal process S52 together with the water washing process S40 (see Figures 8 and 9). These processes may be performed in parallel with the water washing process S40 or after the water washing process S40. In addition, either the oxidation process S51 or the unburned carbon removal process S52 may be performed.

[0134] Figure 8 is a schematic diagram showing the processing flow when both the oxidation process S51 and the unburned carbon removal process S52 are performed in this embodiment. Figure 9 is a schematic diagram showing the structure of the washing equipment 40 when these processes S51 and S52 are performed, following Figure 7. In addition to the washing equipment 40, Figure 9 also shows the gas supply device 51 and the flotation device 53.

[0135] (Oxidation step S51) The oxidation process S51 is a process of oxidizing the fine powder B1F. For example, this can be performed by adding a pH adjusting agent to the powder dissolution tank 43 and washing it with water in the washing process S40. This allows the washing process S40 and the oxidation process S51 to be carried out in parallel.

[0136] By reducing the pH during washing, the chlorine contained in the fine powder B1F can be dissolved more efficiently in water compared to when the pH is not adjusted. Furthermore, the calcium component contained in the fine powder B1F is more easily converted into slow-reactive calcium carbonate or calcium sulfate, which is added to cement clinker Cn1 during the production of cement Cn2. As a result, the dehydrated product Ck1 derived from the fine powder B1F obtained after the washing process S40 becomes suitable as a cement admixture with minimal quality variation.

[0137] The pH of slurry Lr1 in oxidation step S51 is preferably pH 4 to 13, and more preferably pH 5 to 12.

[0138] There are no particular restrictions on the pH adjusting agent as long as it can reduce the pH of slurry Lr1. Examples include acid solutions such as sulfuric acid and CO2-containing gases. As CO2-containing gases, combustion exhaust gas from cement kiln 12, or combustion exhaust gas from biomass incineration facilities or biomass power plants can be used. Since these exhaust gases contain carbon dioxide (CO2), the pH can be adjusted from neutral to weakly alkaline by blowing this combustion exhaust gas into slurry Lr1. This makes it easier to carbonate the calcium components contained in fine powder B1F and react them into the form of calcium carbonate.

[0139] Figure 9 illustrates, as an example, a case in which CO2-containing gas G1 is supplied from a gas supply device 51 to slurry Lr1 in a powder dissolving tank 43. In this case, the gas supply device 51 corresponds to the device used to supply combustion exhaust gas from a cement kiln 12, or combustion exhaust gas from a biomass incineration facility or biomass power plant, etc., to the powder dissolving tank 43.

[0140] The CO2-containing gas G1 only needs to contain carbon dioxide, but to promote efficient carbonation, a carbon dioxide concentration of 10% or more is preferable, and 20% or more is more preferable. In addition, among the combustion exhaust gases, the gas after collecting chlorine bypass dust from the clinker production facility 10 should contain sulfur oxides (SO2). x Since it contains harmful gases such as ), injecting this gas into slurry Lr1 can also be expected to have the effect of immobilizing sulfur oxides.

[0141] In this way, by using the combustion exhaust gas from the clinker manufacturing facility 10, combustion exhaust gas containing carbon dioxide can be obtained on-site and used to modify the fine powder B1F, and the modified fine powder B1F (dehydrated material Ck1) can be used as a cement admixture. Alternatively, by using the combustion exhaust gas from a biomass incineration facility or a biomass power plant, the fine powder B1F can be modified using the combustion exhaust gas containing carbon dioxide obtained on-site, and if this is transported to the clinker manufacturing facility 10 or the crushing facility 31, it can be immediately used as a cement admixture.

[0142] Furthermore, in the washing process S40, waste liquid obtained from the amine-based carbon dioxide recovery device may be added to the powder dissolution tank 43 and washed with water. In amine-based carbon dioxide recovery devices used to recover carbon dioxide from exhaust gases of factories, etc., the liquid containing degraded amines is usually discarded, but this method allows for the effective utilization of that waste liquid.

[0143] Amines are known to react with carbon dioxide to promote the generation of carbonate ions, thereby efficiently advancing the carbonation of calcium components. Furthermore, amines are also known to function as grinding aids when grinding cement clinker Cn1 in the grinding equipment 31. Amines are those having both an amino group and a hydroxyl group in their molecules. Examples of amines used as grinding aids include monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), diglycolamine (DGA), diisopropanolamine (DIPA), methyldiethanolamine (MDEA), and triisopropanolamine (TIPA). Therefore, dehydrated Ck1 derived from fine powder B1F, incorporating amines introduced from the added wastewater, is suitable as a cement admixture because it is expected to provide functionality as a grinding aid in subsequent processes.

[0144] Alternatively, CO2-containing gas G1 may be blown into the dehydrated material Ck1 obtained through the dehydration process S43. This method carbonizes the easily reactive calcium components remaining in the dehydrated material Ck1, thereby further improving the homogenization of the quality of the cement Cn2 produced using this dehydrated material Ck1. Furthermore, this method is also expected to have the effect of drying the moisture contained in the dehydrated material Ck1.

[0145] The gas injection means (gas supply device 51) only needs to be able to bring the dehydrated material Ck1 into contact with CO2-containing gas, and the method is not limited. For example, means such as circulating CO2-containing gas through a container filled with dehydrated material Ck1 or passing the dehydrated material Ck1 through an exhaust gas flue can be used. Also, similar to the injection into slurry Lr1 described above, combustion exhaust gas from a cement kiln 12, or combustion exhaust gas from a biomass incineration facility or biomass power plant may be injected into the dehydrated material Ck1.

[0146] This oxidation step S51 corresponds to step (d).

[0147] (Unburned carbon removal process S52) The unburned carbon removal process S52 is a process for removing unburned carbon contained in the fine powder B1F. As mentioned above, the fine powder B1F obtained after classification has a higher loss on ignition compared to the coarse powder B1C and contains a large amount of unburned carbon. For this reason, when fine powder B1F is used as a raw material for cement clinker Cn1, it may cause the preheater 11 to overheat, and when used as an admixture, it may cause the concrete to darken or its fluidity to decrease.

[0148] Specifically, during the washing process S40, a method can be employed in which the de-burned carbon agent D1, such as oil or a surfactant, is added to the powder dissolution tank 43 from the de-burned carbon agent supply device 52 and then subjected to stirring and other treatments. The obtained slurry Lr2a is then subjected to flotation treatment in the flotation device 53, for example, by adding a predetermined foaming agent, and is separated into floss containing unburned carbon and tail from which unburned carbon has been removed or reduced. The slurry Lr2b, as tail, is then sent to the solid-liquid separator 46 for solid-liquid separation.

[0149] As a result, the washing process S40 and the unburned carbon removal process S52 are carried out in parallel and continuously.

[0150] This unburned carbon removal process S52 corresponds to process (e).

[0151] As a result of the washing process S40, the chlorine concentration (chlorine content) in the fine powder B1F is reduced, for example, typically to 0.01% by mass to 0.2% by mass, and more typically to 0.02% by mass to 0.1% by mass.

[0152] The washing process S40 reduces the total alkali metal concentration in the fine powder B1F to, for example, typically 1% to 8% by mass, and more typically to 3% to 6% by mass.

[0153] The washing process S40 reduces the sulfur oxide concentration in the fine powder B1F to, for example, typically 0.5% to 4% by mass, and more typically to 1% to 3% by mass.

[0154] The washing process S40 reduces the amount of selenium (Se) leached from the fine powder B1F to, for example, typically 0.002 mg / L to 0.02 mg / L, and more typically to 0.005 mg / L to 0.01 mg / L. In addition, the hexavalent chromium (Cr) of the fine powder B1F is reduced. 6+ The elution levels are reduced to, for example, typically 0.01 mg / L to 0.1 mg / L, and more typically to 0.02 mg / L to 0.05 mg / L. These elution levels of selenium and hexavalent chromium can be measured by well-known methods. A preferred example of a measurement method is to prepare a test solution in accordance with JIS K 0058-1 "Chemical Test Methods for Slags - Part 1: Elution Test Methods 5. Testing in the Form of Use," and then measure the selenium by ICP mass spectrometry and the hexavalent chromium by diphenylcarbazide spectrophotometric analysis.

[0155] Furthermore, although the alkali metal content of the dehydrated material Ck1 derived from the fine powder B1F obtained by the method of this embodiment is reduced by the washing process S40, it is still expected to have a higher alkali metal content than coal ash. Therefore, if the dehydrated material Ck1 is used as a raw material for cement clinker Cn1, cement Cn2 with a high alkali metal content may be produced. In addition, the main component of the cement additive obtained from wastewater W4 is alkali metal salts. Consequently, if these are present in large quantities in concrete (cement mixture Cn3), alkali-silica reactions may occur depending on the aggregates used (CA, FA).

[0156] Therefore, when adding dehydrated material Ck1 derived from fine powder B1F in the manufacturing process of cement Cn2, in order to reduce the possibility of alkali-silica reaction, latent hydraulic substances such as blast furnace slag, fly ash, volcanic ash, volcanic rock, and calcined clay may also be added as cement admixtures or concrete admixtures. Furthermore, the addition of such latent hydraulic substances and pozzolanic substances can also be applied when using fine powder B1F that has not undergone the washing process S40, as in the first embodiment.

[0157] (modified version) In this embodiment, several variations are possible.

[0158] <1> As shown in Figure 10, a washing process may also be performed on the coarse powder B1C obtained after the classification process S10 (washing process S40a). In this case, as shown in Figure 11, the manufacturing system 1 may be equipped with a washing facility 40a for washing the classified coarse powder B1C. When performing the washing process S40a on the coarse powder B1C, the same method as the washing process S40 for the fine powder B1F described above can be used. The dewatered material Ck1 obtained after washing the coarse powder B1C is added in the input process S20 as a partial substitute material for the fine aggregate FA when manufacturing the cement mixture Cn3.

[0159] As mentioned above, although the chlorine content of coarse powder B1C is lower than that of fine powder B1F, a further reduction in chlorine content can be expected by performing the water washing process S40a as in this embodiment.

[0160] As shown in Figure 12, the oxidation process S51a and the unburned carbon removal process S52a may be performed together with the washing process S40a. The oxidation process S51a and the unburned carbon removal process S52a can be performed using the same methods as the oxidation process S51 and the unburned carbon removal process S52 described above.

[0161] The washing process S40a corresponds to process (c), the oxidation process S51a corresponds to process (d), and the unburned carbon removal process S52a corresponds to process (e).

[0162] <2> In the processing flow shown in Figure 10, the classification process S10 and the washing process (S40, S40a) may be executed in parallel. In this case, the manufacturing system 1 is equipped with a classification facility 20 (40) that has a washing function (see Figure 13). In this case, a wet classifier is preferably used.

[0163] Furthermore, the raw ash (biomass ash B1) may be washed in step S40 before the classification process S10. In this case, wet classification is used in classification process S10.

[0164] [Third Embodiment] A third embodiment of the cement mixture and cement manufacturing method will be described, focusing on the differences from the first and second embodiments. Figure 14 is a schematic diagram showing the processing flow of the manufacturing method in this embodiment. Figure 15 is a schematic block diagram showing the manufacturing system 1 that implements the manufacturing method of this embodiment, following Figure 2. The manufacturing system 1 of this embodiment shown in Figure 15 differs from the first embodiment in that it includes analytical equipment 61 and crushing equipment 62.

[0165] (Analysis step S61) The coarse powder B1C obtained in the classification process S10 is analyzed in the analytical equipment 61, and the proportion of amorphous material is measured. This measurement may be performed on a portion extracted from the obtained coarse powder B1C. The analytical equipment 61 includes an X-ray diffractometer and a computing device, and as a measurement method, a method of calculating the measurement results of X-ray diffraction by Rietveld analysis (XRD-Rietveld method) can be suitably used.

[0166] (Grinding process S62) As described above in the first embodiment, the coarse powder B1C obtained in the classification step S10 typically has an amorphous content of 60% by mass or less. This amorphous content is preferably 50% by mass or less, more preferably 40% by mass or less, and particularly preferably 30% by mass or less. However, depending on the properties of the biomass ash (raw ash) B1, the amorphous content of the coarse powder B1C obtained in the classification step S10 may be relatively high.

[0167] Based on the analysis results in analysis step S61, if the proportion of amorphous material in the coarse powder B1C is higher than the standard value, it is ground by the grinding equipment 62. The grinding equipment 62 can utilize the same equipment as the grinding equipment 31.

[0168] When coarse powder B1C, which has a higher proportion of amorphous material than the standard value, is used as a partial substitute for fine aggregate FA in the production of cement compound Cn3, it may cause alkali-silica reaction in the cement compound Cn3. On the other hand, this coarse powder B1C is obtained after classification of biomass ash B1, and has low calcium, sulfur, chlorine, and carbon content, making its composition similar to coal ash. For this reason, it can be used as a raw material for cement clinker Cn1 or as an admixture in the production of cement Cn2.

[0169] Because the coarse powder B1C has a large particle size, it is crushed in the crushing process S62, and the resulting crushed coarse powder B2C is added to the cement Cn2 manufacturing process. This crushing process S62 corresponds to process (g), and the process S30 in which the crushed coarse powder B2C is added to the cement Cn2 manufacturing process corresponds to process (f2).

[0170] However, if the coarse powder B1C is fed into the crushing equipment 31, the crushing equipment 62 is not necessarily required. Furthermore, if the coarse powder B1C is used as a raw material for cement clinker Cn1, the crushing equipment 62 may be used as a raw material crusher in the clinker manufacturing equipment 10.

[0171] [Alternative Embodiment] In the above embodiment, the case was described in which both the coarse powder B1C and the fine powder B1F obtained after classifying biomass ash B1 are used in the production of cement Cn2 or cement mixture Cn3. However, the present invention is also applicable when the coarse powder B1C obtained after classifying biomass ash B1 is used at least in the production of cement mixture Cn3. In other words, the fine powder B1F may be used for other purposes. [Examples]

[0172] [Verification 1] We obtained incineration fly ash BA-1 (particle size D50 of 47.2 μm, ignition loss (ig. loss) at 975°C of 4.17%) from biomass power generation facility P1, which uses palm kernel shells as fuel and generates electricity using a circulating fluidized bed furnace (biomass ash B1), and investigated the effect of classifying it on the component composition of biomass ash. The coal content in the mixed fuel of palm kernel shells and coal was 10 mass%. The particle size distribution of this incineration fly ash BA-1 (using a laser diffraction particle size distribution analyzer: Microtrac-Bell MT3300EX II) is shown in Figure 3.

[0173] 《Examination Method》 The testing method is described below.

[0174] <1. Classification> Biomass ash B1 was sieved using a sieve (spin air sieve: SAR-75 / 200, manufactured by Seishin Corporation) with mesh sizes set to achieve the classification points shown in Table 1. Fine powder B1F was obtained as the sieved portion, and coarse powder B1C was obtained as the sieved residue. This process corresponds to classification step S10. These classification points were set based on the particle size distribution shown in Figure 3. In the test, biomass ash B1 was classified at three different classification points: 32 μm, 45 μm, and 90 μm. In the following, to clarify that biomass ash B1 is unclassified, it may be referred to as "raw ash B1".

[0175] The particle size distribution of the classified biomass ash is shown in Table 1. Table 1 also shows the coarse powder B1C obtained after classifying incinerated fly ash BA-2, which was obtained from biomass power plant P2 (a different biomass power plant from biomass power plant P1), with a classification point of 45 μm. The particle size distribution was measured using a laser diffraction particle size analyzer (Microtrac-Bell MT3300EX II).

[0176] [Table 1]

[0177] <2. Mineral Composition Analysis> The mineral composition of raw ash B1 (code #1) derived from incinerator fly ash BA-1, coarse powder B1C (code #2) obtained by classifying raw ash B1 at 45 μm, fine powder B1F (code #3) obtained by classifying raw ash B1 at 45 μm, coarse powder B1C (code #6) obtained by classifying raw ash B1 at 90 μm, and coarse powder B1C (code #8) derived from incinerator fly ash BA-2 was measured using the XRD / Rietveld method.

[0178] Furthermore, the raw ash B1 (designation #1) derived from incinerated fly ash BA-1 was further processed by adding 20% ​​by mass (16.7% by mass moisture content) of water, storing it at 20°C for 3 days, and drying it at 105°C to obtain wet ash. The mineral composition of this wet ash was then measured using the same method. This biomass ash is designated "designation #1W". In addition, the mineral composition of the coarse powder B1C (designation "designation #2W"), which was obtained by classifying this wet ash raw ash B1 (#1W) at 45 μm, was also measured using the same method. An air jet sieve (Hosokawa Micron Corporation, e200LS) was used to classify the wet ash raw ash B1 (#1W).

[0179] First, X-ray diffraction patterns were measured using an X-ray diffractometer (Bruker AXS D8 ADVANCE A-25) with samples prepared by adding 10% corundum (Al2O3) as an internal standard to biomass ash corresponding to each of the above symbols (#1, #2, #3, #6, #8, #1W, #2W). The X-ray diffraction measurement conditions were CuKα rays, tube voltage 50kV, tube current 40mA, scanning range 5°~65°(2θ), step size 0.0234, and scan speed 0.13sec / step. Next, Rietveld analysis was performed using software (Bruker AXS TOPAS Ver.6.0) with the obtained diffraction patterns to obtain quantitative results of the mineral composition.

[0180] From the obtained results, the amorphous mass was calculated from the corundum quantitative value using the following formula (1). G = 100·(AR) / {A·(100-R) / 100} …(1) In equation (1), G is the amorphous mass (%), R is the mixing ratio of Al2O3 (%), and A is the quantitative value of Al2O3 (%).

[0181] Furthermore, the quantitative results obtained from the Rietveld analysis were standardized so that the total amount of composition excluding the quantitative value of corundum equaled 100%, and then this value was further standardized by subtracting the amorphous mass from this value to determine the mineral composition of each biomass ash (#1, #2, #3, #6, #8, #1W, #2W).

[0182] The results of the mineral composition analysis are shown in Table 2.

[0183] [Table 2]

[0184] According to Table 1, the comparison results of #1 to #3 confirm that the coarse powder B1C obtained by classification process S10 has a lower amorphous content than the fine powder B1F. Furthermore, the comparison results of #1W and #2W confirm that, similarly, in the case of wet ash, the coarse powder B1C obtained by classification process S10 has a lower amorphous content than the fine powder B1F.

[0185] Figure 16 shows a polarized light microscope image of raw ash B1 derived from incinerated fly ash BA-1. In detail, raw ash B1 was extracted and solidified with epoxy resin, then chips of approximately 20 mm x 30 mm were cut out to create mirror-polished thin sections approximately 20 μm thick. These mirror-polished thin sections were observed under a polarized light microscope to confirm the materials constituting the sample.

[0186] As shown in the image in Figure 16, it can be confirmed that only a portion of the quartz particles around the quartz particles has melted and vitrified (amorphized), indicating that the proportion of amorphous material in the coarser powder with relatively larger particle sizes is low.

[0187] <3. Compression strength test, 4. Alkali-silica reaction test> In accordance with JIS R 5201 "Physical Testing Methods for Cement," ordinary Portland cement, water, and fine aggregate were mixed to prepare mortar as test specimens, and a compressive strength test was performed on this mortar.

[0188] Furthermore, in accordance with JIS A 1146 "Test Method for Alkali-Silica Reactivity of Aggregates (Mortar Bar Method)," mortar was prepared as a test specimen by mixing ordinary Portland cement, water, and fine aggregate, and an alkali-silica reactivity test was performed on this mortar.

[0189] Comparative Example 1 used only mountain sand as fine aggregate. Examples 1 to 5 used a mixture in which a portion of the fine aggregate was replaced with coarse biomass ash powder B1C (#2, #6, #8) from Table 2 at a predetermined replacement rate. The properties of the mountain sand NS used in the tests are shown in Table 3. The results of the compressive strength test and alkali-silica reaction test for Examples 1 to 5 and Comparative Example 1 are shown in Table 4.

[0190] [Table 3]

[0191] [Table 4]

[0192] According to Table 4, in all of Examples 1-4, which used coarse powder B1C (#2,#6) derived from incinerator fly ash BA-1, and in Example 5, which used coarse powder B1C (#8) derived from incinerator fly ash BA-2, the alkali-silica reactivity test results were classified as Category A, confirming that alkali-silica reaction is unlikely to occur, similar to Comparative Example 1, which used only mountain sand NS. This is thought to be because the proportion of amorphous material in all of the coarse powders B1C (#2,#6,#8) is suppressed to 60% by mass or less, thereby keeping the reactivity to alkali metals low. However, in Example 5, which has a relatively high proportion of amorphous material (48.2%) among Examples 1-5, the expansion rate in the mortar bar method is higher than in the other examples.

[0193] Furthermore, comparing Examples 1 to 3, in which the substitution rate of coarse powder B1C (#2) obtained by classification at the same classification point (45 μm) was varied, it can be seen that the compressive strength of the mortar specimens increased as the substitution rate increased. This is presumed to be because, as the substitution rate increased, the amount of amorphous material increased within a range that does not promote the alkali-silica reaction, increasing the reactivity with the cement paste and thus increasing the adhesion strength between the cement paste and the fine aggregate. In Example 4, where D10 exceeds 110 μm, the expansion rate and compressive strength are lower than in the other examples.

[0194] <5. Chemical composition analysis> The chemical composition was measured for raw ash B1 (#1) derived from incinerated fly ash BA-1, each coarse powder B1C (#2, #4), each fine powder B1F (#3, #5), wet ash of raw ash B1 (#1W), and coarse powder B1C (#2W) obtained by classifying wet ash raw ash B1 (#1W) at 45 μm. In addition, coarse powder B1C (#9) and fine powder B1F (#10) were obtained by classifying raw ash B1 with a classification point of 20 μm, and the chemical composition was measured for these as well. Furthermore, raw ash B1 (#1) and fine powder B1F (#3) classified at 45 μm were prepared by washing them with water using the following method (#1Wp, #3Wp), and the chemical composition was measured in the same manner.

[0195] The procedure for the water washing process is as follows. This water washing process corresponds to step S40. (Procedure 1) 100g of biomass ash (B1, B1F) and 400g of tap water were placed in a beaker to form a slurry, which was then stirred with a stirrer at 400 rpm for 30 minutes. When adjusting the pH by introducing CO2 gas during washing, the flow rate was adjusted while monitoring the pH of the liquid with a pH meter. (Step 2) After stopping the stirring, the mixture was filtered using a Buchner funnel. The resulting cake on the filter paper was then washed with 400g of tap water and collected. (Step 3) After the recovered cake was air-dried, its mass was measured and various analyses were performed.

[0196] The chemical composition was measured using the following method. For each prepared sample (#1-#5, #9-#10, #1W, #2W, #1Wp, #3Wp), the chemical composition was measured using a calibration curve (coal ash) method with an X-ray fluorescence spectrometer (Rigaku ZSX Primus II). The ignition loss (ig. loss) for each sample was measured according to the method specified in JIS R 5202 "Methods for Chemical Analysis of Cement".

[0197] Table 5 shows the chemical composition analysis results for each sample (#1~#5, #9~#10, #1W, #2W, #1Wp, #3Wp).

[0198] [Table 5]

[0199] According to the results in Table 5, when raw ash B1, which is dry ash, was classified using the point between the peaks on the fine and coarse grain sides when the particle size distribution is expressed by frequency, most of the chlorine and sulfur (SO3) components were found in the fine powder (B1F). Furthermore, it was confirmed that the chlorine components could be efficiently removed by washing with water. Therefore, it was found that the fine powder, especially after washing, is suitable as a cement admixture. On the other hand, it was confirmed that the chlorine components could be efficiently removed from the coarse powder B1C simply by classification.

[0200] On the other hand, when comparing raw ash B1 that has been wet-ashed (#1W) with coarse powder B1C (#2W) obtained by classifying it at 45 μm, it was confirmed that the degree of reduction in chlorine concentration due to classification was low. This is presumed to be because coagulation and hydration reactions occurred when raw ash B1 was wet-ashed, and as a result the chlorine (Cl) was incorporated into the resulting hydrate, the removal rate by classification decreased. Wet-ashed raw ash B1 (#1W) underwent a hydration reaction, and its ignition loss was greater than that of dry raw ash B1.

[0201] <6. Physics Test> For raw ash B1 (#1) derived from incinerated fly ash BA-1, and coarse powder B1C (#2) and fine powder B1F (#3) obtained with a classification point of 45 μm, the Blaine specific surface area, flow value ratio, and activity index were measured according to the method conforming to Annex C of JIS A 6201 "Fly Ash for Concrete". Furthermore, coarse powder B1C (#2) was milled to a particle size similar to that of fine powder B1F, and the Blaine specific surface area, flow value ratio, and activity index were measured in the same manner. The pulverized material (#2C) obtained by grinding coarse powder B1C is a simulation of the symbol B2C in Figure 14. The measurement results are shown in Table 6.

[0202] [Table 6]

[0203] Table 6 shows that when fine powder B1F, obtained by classifying raw ash B1, was used as a mixed material, the activity index was higher than when raw ash B1 was used. For coarse powder B1C, the Blaine specific surface area was 4000 cm². 2 It was found that grinding the material to a level of 1 / g or more allows it to be used as a pozzolanic mixture with higher reactivity than raw ash B1. Therefore, it is suggested that grinding coarse powder B1C, which has a relatively higher proportion of amorphous material, can be used as a mixture for cement Cn2, which has a higher reactivity.

[0204] [Verification 2] Fly ash (particle size D50 (frequency) 45.3 μm, ignition loss (ig. loss) at 750°C 2.3%) was obtained from biomass power generation facility P2, which uses woody biomass (thinned wood) as fuel and generates electricity using a circulating fluidized bed furnace. The effects of washing this fly ash with water, and the presence or absence of an oxidation process (particularly a carbonation process) during the washing, on its component composition were investigated. The washing method was the same as in Verification 1.

[0205] Table 7 below shows the levels for each flushing condition.

[0206] [Table 7]

[0207] "analysis" The obtained samples were analyzed using the following methods. Determination of Cl: After treating the sample with nitric acid, Cl was measured by potentiometric titration. Quantitative determination of K and Na: After acid hydrolysis of the sample, the K and Na were measured by ICP emission spectrometry. Se,Cr 6+ Leaching test: After preparing the test solution in accordance with JIS K 0058-1 "Chemical Test Methods for Slags - Part 1: Leaching Test Methods 5. Tests in Use Form", Se was tested by ICP mass spectrometry, and Cr 6+ These values ​​were measured by diphenylcarbazide spectrophotometric spectroscopy. Quantitative determination of C, Mg, Al, Si, P, S, Ca, and Fe: Samples dried at 40°C were measured using an X-ray fluorescence spectrometer (FP method: fundamental parameter method).

[0208] Furthermore, the amount of calcium carbonate in the raw ash and the obtained sample was determined by measuring the mass loss around 600°C to 700°C when approximately 50 mg of the sample was heated to 1000°C at a heating rate of 20°C / min in a nitrogen atmosphere, and then calculating the ratio of this mass loss to that of the reagent (using a NETZSCH TG-DTA 2000SR). In addition, the amount of calcium hydroxide in the calcined raw ash and the obtained sample was determined by measuring the endothermic heat loss around 400°C when approximately 50 mg of the sample was heated to 1000°C at a heating rate of 10°C / min in a nitrogen atmosphere, and then calculating the ratio of this mass loss to that of the reagent (using a NETZSCH DSC404F3).

[0209] The measurement results are shown in Tables 8 and 9.

[0210] [Table 8]

[0211] [Table 9]

[0212] Table 8 shows that washing the raw ash effectively removes almost all of the chlorine, and it was confirmed that when used as an admixture, the amount of chlorine in the cement after water hardening meets the acceptable standard of 0.035% by mass or less, which means there is no risk of corrosion to reinforcing steel, etc. In other words, when the biomass ash is classified after washing, it can be seen that it contains almost no chlorine in both the fine powder and coarse powder portions.

[0213] Furthermore, as shown in Table 8, water-soluble selenium and hexavalent chromium contained in the raw ash are effectively removed by washing with water, and it has become clear that the risk of heavy metal leaching when used as a mixed material is reduced.

[0214] As shown in Table 9, this biomass ash, whose main components are SiO2 and CaO, was found to be useful as a highly reactive pozzolanic mixture.

[0215] The results for Level 2-2 revealed that washing with water while blowing in CO2 gas increased the CO2 content of the biomass ash after washing. Therefore, it is thought that at least a portion of the components for pH adjustment were immobilized in the ash after the washing operation, and calcium carbonate was generated. In addition, calcium hydroxide disappeared when washing with water while blowing in CO2 gas. In Table 9, a calcium hydroxide content of less than 0.01% means that it is below the detection limit.

[0216] Table 10 below shows the results of investigating the form of calcium components in ash using the XRD method.

[0217] [Table 10]

[0218] According to Tables 9 and 10, the raw ash contained the following calcium compounds: CaO (quicklime), Ca(OH)2 (slaked lime), CaCO3 (calcium carbonate), and CaSO4 (gypsum). In contrast, at level 2-1, which was washed with water without pH adjustment, the presence of CaO (quicklime) disappeared, and a decrease in the presence of Ca(OH)2 (slaked lime) was observed. Furthermore, at level 2-2, which was washed with water under pH 9 conditions while blowing in CO2 gas, the presence of CaO (quicklime) and Ca(OH)2 (slaked lime) disappeared, and an increase in calcium carbonate was observed.

[0219] [Verification 3] Incinerated fly ash (particle size D50 (frequency) 20.0 μm, ignition loss (ig. loss) at 750°C 6.1%) was obtained from biomass power generation facility P3, which uses wood pellets and palm kernel shells as fuel for power generation in a stoker furnace, and the same tests as for verification were performed. The results are shown in Tables 11 and 12. Note that in Level 3-2, sulfuric acid was added during washing to adjust the pH.

[0220] [Table 11]

[0221] [Table 12]

[0222] According to Table 11, as in Verification 2, washing the raw ash with water effectively removed almost all of the chlorine, and it was confirmed that the acceptable standard of 0.035% by mass or less, which is evaluated as not posing a risk of corrosion to reinforcing steel etc. after the cement has been water-hardened when used as an admixture, was met. In other words, when the biomass ash is classified after washing with water, it can be seen that it contains almost no chlorine in both the fine powder and coarse powder sides.

[0223] Table 12 shows that this biomass ash is mainly composed of SiO2 and CaO, and is useful as a highly reactive pozzolanic mixture. Furthermore, it was found that the SO3 content increased when sulfuric acid was added and washed with water. Therefore, it is considered that at least a portion of the sulfuric acid component used for pH adjustment is immobilized in the ash after the washing process. [Explanation of symbols]

[0224] 1: Manufacturing System 3: Raw material tank 5: Powder storage tank 10: Clinker manufacturing equipment 11: Preheater 12: Cement Kiln 13: Klinka Cooler 20: Classification equipment 31: Grinding equipment 33: Mixing equipment 40,40a: Washing equipment 42:Liquid supply device 43: Powder dissolving tank 44: Slurry stirring device 46:Solid-liquid separator 47: Conveying equipment 49: Water washing device 51: Gas supply equipment 52: Decomposing unburned carbon agent supply device 53: Flotation apparatus 61:Analysis equipment 62: Grinding equipment B1: Biomass ash (raw ash) B1C: Coarse powder B1F: Fine powder B2C: Crushed coarse powder Ck1: Dehydrated product Cn1: Cement clinker Cn2: Cement Cn3: Cement mixture D1: Decompression agent for unburned carbon FA: Fine aggregate G1: CO2-containing gas Lr1, Lr2, Lr2a, Lr2b: Slurry W1,W2,W3:Water W4: Drainage Y1: Cement clinker raw material

Claims

1. (a) A process of classifying biomass ash into coarse powder and fine powder using a standard value within the range of 30 μm to 100 μm as the classification point, The process includes step (a) of mixing the coarse powder obtained in step (a) with fine aggregate other than the coarse powder, cement, and water without grinding it, and step (b) of The coarse powder obtained in step (a) above has a chlorine (Cl) content of 0.2% by mass or less before being washed with water. Step (b) is a step of mixing the coarse powder, which has an amorphous content of 60% by mass or less, with fine aggregate other than the coarse powder, cement, and water. A method for producing a cement mixture, characterized in that the amount of coarse powder mixed in step (b) is such that the ratio of the coarse powder to the total amount of the coarse powder and fine aggregate other than the coarse powder is 5% by mass to 40% by mass.

2. (a) A process of classifying biomass ash into coarse powder and fine powder using a standard value within the range of 30 μm to 100 μm as the classification point, The process includes step (a) of mixing the coarse powder obtained in step (a) with fine aggregate other than the coarse powder, cement, and water without grinding it, and step (b) of The coarse powder obtained in step (a) above has a chlorine (Cl) content of 0.2% by mass or less before being washed with water. The above step (b) is, (b1) A step of mixing the coarse powder with an adjusting powder which is a powder made of another biomass ash having a lower proportion of amorphous material than the coarse powder, so that the proportion of amorphous material in the mixture of the coarse powder and the adjusting powder is 60% by mass or less. The process includes (b2) mixing the mixture obtained in step (b1) with fine aggregate other than the mixture, cement, and water. A method for producing a cement paste, characterized in that the amount of the mixture mixed in step (b2) is such that the ratio of the mixture to the total amount of the mixture and other fine aggregates is 5% by mass to 40% by mass.

3. The process includes a step (c) of washing the coarse powder obtained in step (a) with water, The method for producing a cement mixture according to claim 1 or 2, characterized in that step (b) is a step of mixing the coarse powder after it has been washed with water in step (c).

4. A method for producing a cement mixture according to claim 3, characterized in that it includes a step (d) of oxidizing the biomass ash during or after the execution of step (c).

5. A method for producing a cement mixture according to claim 3 or 4, characterized in that, during the execution of step (c), a step (e) is taken to remove unburned carbon contained in the biomass ash.

6. A method for producing a cement mixture according to claim 1 or 2, characterized by having a step (f1) of adding the fine powder obtained in step (a) to at least one of the following: a cement clinker raw material to be put into a cement kiln, cement clinker obtained from the cement kiln, or cement obtained after grinding treatment of the cement clinker.

7. The process includes a step (c) of washing the biomass ash with water before or after the execution of step (a), The method for producing a cement mixture according to claim 6, characterized in that step (f1) is a step of adding the fine powder that has been washed with water in step (c).

8. The process includes a step (g) of grinding the coarse powder obtained in step (a) above, wherein the proportion of amorphous material exceeds 60% by mass. A method for producing a cement mixture according to claim 6 or 7, characterized by having a step (f2) of adding the coarse powder crushed in step (g) to at least one of the cement clinker raw material, the cement clinker, or the cement obtained after crushing the cement clinker.

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