Method for producing low-potassium woody biomass ash, method for reducing potassium in woody biomass ash, method for producing cement, and method for recycling woody biomass ash as cement resource

Abstract

To provide a production method for obtaining low-kalium woody biomass ash from the woody biomass ash using a low-concentration hydrogen chloride gas.SOLUTION: There is provided a production method for obtaining low-kalium woody biomass ash in which the kalium content in woody biomass ash is reduced. The method comprises: a first process of contacting the woody biomass ash with a hydrogen chloride-containing gas at 700-1,100°C under a gas atmosphere including hydrogen chloride; and a second process of removing a water-soluble component from the ash by cleaning the contacted ash using water. The average volume concentration of hydrogen chloride in the hydrogen chloride-containing gas is in a range from 0.01 to 10 vol.%.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing low-potassium woody biomass ash, a method for reducing potassium in woody biomass ash, a method for producing cement, and a method for recycling woody biomass ash as a cement resource.

Background Art

[0002] Since the start of the Feed-in Tariff (FIT) system for renewable energy, the number of certified woody biomass power generation facilities has been increasing because stable electricity sales business profits can be expected. Along with this, woody biomass ash, which is the combustion ash of woody biomass, is expected to have an increasing generation volume in the future, and the establishment of an effective utilization method is desired.

[0003] One method for effectively utilizing a large amount of woody biomass ash is cement recycling. However, woody biomass ash has a concentrated potassium content contained in plants, and if this is used as a cement raw material as it is, the amount of alkali metals (sodium and potassium, especially potassium) in the cement may increase and the quality may deteriorate. For this reason, the development of a technology for reducing the potassium content from woody biomass ash is desired.

[0004] Conventionally, technologies for reducing the amount of alkali metals in waste containing a large amount of alkali metal components are widely known. Such technologies include a method of reacting a component containing a chlorine atom with an alkali metal and removing it by volatilization or water washing.

[0005] For example, Patent Document 1 discloses a method of mixing woody biomass ash and a solid chlorine-containing substance together, heating them, and removing alkali metals by water washing.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, most of the woody biomass ash generated in woody biomass power generation facilities contains poorly soluble potassium. This poorly soluble potassium is considered to have potassium incorporated into the aluminosilicate (crystalline) structure and cannot be easily removed.

[0008] In addition, when using a gas containing high-concentration hydrogen chloride (hydrogen chloride gas), the possibility of problems such as corrosion of pipes by hydrogen chloride, deterioration of furnace materials by molten chlorides, and blockage of pipes by volatilized large amounts of chlorides increases. Therefore, a method of using a lower-concentration (for example, 0.01 to 10% by volume) hydrogen chloride gas to remove potassium more efficiently is required.

[0009] The main object of the present invention is to provide a method for producing low-potassium woody biomass ash in which potassium is reduced from woody biomass ash by using a low-concentration hydrogen chloride gas.

Means for Solving the Problems

[0010] As a result of intensive studies by the present inventors to solve the above problems, it was found that contacting woody biomass ash with a gas containing a low-concentration hydrogen chloride at a predetermined temperature to generate potassium chloride and removing the potassium chloride by washing with water is the most practical for reducing potassium from woody biomass ash, and the present invention has been completed.

[0011] One aspect of the present invention relates to a method for producing low-potassium wood biomass ash with a reduced potassium content obtained from wood biomass ash. The production method includes a first step of contacting wood biomass ash with a gas containing hydrogen chloride at 700 to 1100 °C in a gas atmosphere containing hydrogen chloride, and a second step of washing the wood biomass ash after contact with water to remove soluble components. The average volume concentration of hydrogen chloride in the gas containing hydrogen chloride is 0.01 to 10% by volume. The wood biomass ash may have an aluminosilicate structure composed of silicon and aluminum. According to the production method, it is possible to reduce the amount of hardly soluble potassium incorporated into the aluminosilicate (crystal) structure of the wood biomass ash using a low-concentration hydrogen chloride gas, and obtain low-potassium wood biomass ash. Since the potassium content of the low-potassium wood biomass ash is reduced, it can be stably used as a cement raw material.

[0012] In the first step, the contact time between the wood biomass ash and the gas containing hydrogen chloride may be 1 to 120 minutes.

[0013] The gas containing hydrogen chloride may further contain oxygen. That is, the atmosphere for contacting the wood biomass ash with the gas containing hydrogen chloride in the first step may be an oxidizing atmosphere. In this case, the average volume concentration of oxygen in the gas containing hydrogen chloride may be 0.1 to 24% by volume.

[0014] The proportion of fly ash in the wood biomass ash may be 60% by mass or more.

[0015] In the second step, the mass ratio of water to the wood biomass ash after contact (mass of water / mass of the wood biomass ash after contact) may be 1 to 20. In the second step, the water may be hydrochloric acid water containing hydrogen chloride. The hydrochloric acid water may contain hydrochloric acid water obtained by gas-liquid contact of hydrogen chloride in the gas discharged in the first step.

[0016] Another aspect of the present invention relates to a method for reducing potassium in woody biomass ash, which reduces the amount of potassium contained in the woody biomass ash. The potassium reduction method includes a first step of contacting the woody biomass ash with a gas containing hydrogen chloride at 700 to 1100 °C in a gas atmosphere containing hydrogen chloride, and a second step of washing the woody biomass ash after contact with water to remove soluble components. The average volume concentration of hydrogen chloride in the gas containing hydrogen chloride is 0.01 to 10% by volume. According to the potassium reduction method, it is possible to reduce the amount of hardly soluble potassium incorporated into the aluminosilicate (crystal) structure of the woody biomass ash by using a low-concentration hydrogen chloride gas.

[0017] Another aspect of the present invention relates to a method for producing cement. The production method includes a step of using the low-potassium woody biomass ash produced by the above production method as a cement raw material.

[0018] Another aspect of the present invention relates to a method for resource utilization of woody biomass ash as cement. The method for resource utilization of woody biomass ash as cement uses the low-potassium woody biomass ash produced by the above production method as a cement raw material.

Advantages of the Invention

[0019] According to the present invention, there is provided a method for producing low-potassium woody biomass ash in which potassium is reduced from woody biomass ash by using a low-concentration hydrogen chloride gas. Further, according to the present invention, there is provided a method for reducing potassium in woody biomass ash capable of reducing the amount of potassium contained in the woody biomass ash by using a low-concentration hydrogen chloride gas. Furthermore, according to the present invention, there are provided a method for producing cement using the low-potassium woody biomass ash produced by the above production method and a method for resource utilization of woody biomass ash as cement.

Brief Description of the Drawings

[0020]

Figure 1

Mode for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[0022] [Method for Producing Low-Potassium Wood Biomass Ash] A method for producing low-potassium wood biomass ash according to one embodiment is to obtain wood biomass ash with a reduced potassium content from wood biomass ash. The production method of this embodiment includes at least a first step and a second step.

[0023] <First Step> This step is a step of bringing wood biomass ash into contact with a gas containing hydrogen chloride at 700 to 1100°C in a gas atmosphere containing hydrogen chloride. The average volume concentration of hydrogen chloride in the gas containing hydrogen chloride is 0.01 to 10% by volume.

[0024] Wood biomass ash is ash generated when burning wood resources such as forest residues, residues from sawmills, construction waste, and palm husks, and is a concept including the main ash accumulated at the bottom of the combustion device and the fly ash recovered by the dust collector. The main elements contained in these wood biomass ashes are silicon and aluminum that form an aluminosilicate structure, and phosphorus and potassium that are plant nutrient components. In wood biomass ash, most of the potassium is considered to be incorporated into the aluminosilicate (crystalline) structure and exists in a poorly water-soluble state.

[0025] The proportion of fly ash in the wood biomass ash is preferably 60% by mass or more, more preferably 70% by mass or more, and still more preferably 80% by mass or more.

[0026] Since this process uses a gas containing hydrogen chloride, it is usually carried out in a reaction system that allows gas flow and does not leak the gas containing hydrogen chloride. A reaction apparatus capable of providing such a reaction system can be appropriately selected according to the amount of woody biomass ash to be treated, and it may be either a continuous type or a batch type. Examples of the reaction apparatus include an apparatus including a mantle heater, an apparatus including a tubular furnace, a rotary kiln, a fluidized bed furnace, a moving grate type reaction apparatus, a multi-stage furnace reaction apparatus, and the like.

[0027] In this process, woody biomass ash may be introduced into a reaction system heated to 700 to 1100 °C in an atmosphere of a gas containing hydrogen chloride (hereinafter sometimes referred to as "predetermined gas") having an average volume concentration of hydrogen chloride of 0.01 to 10% by volume, and brought into contact with the predetermined gas, or the predetermined gas may be introduced into a reaction system in which the woody biomass ash is heated to 700 to 1100 °C in an atmosphere other than the predetermined gas and brought into contact therewith.

[0028] By bringing the woody biomass ash into contact with the predetermined gas, the reaction represented by the following formula (1) proceeds, and potassium (K 2 O) contained in the woody biomass ash is converted into water-soluble potassium chloride (KCl). K 2 O + 2HCl → 2KCl + H 2 O (1)

[0029] The contact temperature between the woody biomass ash and the predetermined gas is 700 to 1100 °C. When the contact temperature is less than 700 °C, the reaction in which potassium (ions) desorbs from the aluminosilicate structure to form potassium chloride does not proceed sufficiently, and there is a tendency that potassium cannot be sufficiently removed even by the second step described later. When the contact temperature exceeds 1100 °C, the equipment cost and the operation cost tend to increase. The contact temperature is preferably 800 to 1000 °C, more preferably 900 °C to 1000 °C.

[0030] The contact time between the woody biomass ash and the predetermined gas is preferably 1 to 120 minutes. When the contact time is less than 1 minute, the reaction in which potassium (ions) desorbs from the aluminosilicate structure to form potassium chloride tends not to proceed sufficiently. When the contact time exceeds 120 minutes, the potassium removal rate may not improve, and the equipment cost and operating cost tend to increase. The contact time is more preferably 10 to 120 minutes, still more preferably 15 to 120 minutes, and particularly preferably 40 to 90 minutes.

[0031] Note that the starting point of the contact time can be the time when the woody biomass ash is introduced into the reaction system heated to 700 to 1100 °C under a predetermined gas atmosphere, or the time when the predetermined gas is introduced into the reaction system in which the woody biomass ash is heated to 700 to 1100 °C in an atmosphere other than the predetermined gas. When using hydrogen chloride generated by burning chlorine-containing waste as the predetermined gas, the time when the predetermined gas is introduced can be determined, for example, by grasping the relationship between the preheating time and the amount of hydrogen chloride generated in advance and making a judgment based on this.

[0032] The average volume concentration of hydrogen chloride in the gas containing hydrogen chloride is 0.01 to 10% by volume. The average volume concentration of hydrogen chloride is preferably 0.1 to 5% by volume, and more preferably 0.5 to 2% by volume. By adjusting the average volume concentration of hydrogen chloride within such a range, it is possible to obtain a more stable potassium removal effect while suppressing corrosion or deterioration of the equipment. The average volume concentration of hydrogen chloride can be determined, for example, by installing a concentration meter corresponding to hydrogen chloride in the reaction apparatus and tracking the change in the concentration of hydrogen chloride. Also, when using a gas containing hydrogen chloride with a predetermined concentration prepared in advance, the average volume concentration of hydrogen chloride can be the predetermined concentration of hydrogen chloride in the prepared gas. The average volume concentration of hydrogen chloride can be adjusted, for example, by varying the flow rate of air, nitrogen, etc. introduced. When using hydrogen chloride generated by burning chlorine-containing waste described later, the average volume concentration of hydrogen chloride can be adjusted by varying the usage amount of the chlorine-containing waste, the chlorine content of the chlorine-containing waste, the amount of air introduced, etc.

[0033] For hydrogen chloride in a gas containing hydrogen chloride, general industrial gas or reaction gas for general chemical experiments (for example, gas generated by dropping concentrated hydrochloric acid into concentrated sulfuric acid) can be used.

[0034] For hydrogen chloride in a gas containing hydrogen chloride, gas generated by burning chlorine-containing waste in an oxidizing atmosphere may also be used. Examples of chlorine-containing waste include vinyl chloride resin, vinylidene chloride resin, etc. These can be used alone or as a mixture, and waste products containing these can be used. Waste products can include waste wallpaper, waste carpet, construction mixed waste products, etc. The oxidizing atmosphere is not particularly limited as long as it contains oxygen, but preferably the volume concentration of oxygen is 0.1 to 24% by volume. The oxidizing atmosphere may be, for example, an air atmosphere. The temperature when burning chlorine-containing waste is preferably 300 to 1100 °C, more preferably 350 to 1100 °C, still more preferably 500 °C to 1100 °C, and particularly preferably 800 °C to 1000 °C.

[0035] The gas containing hydrogen chloride preferably contains oxygen. That is, the atmosphere in which woody biomass ash is brought into contact with the gas containing hydrogen chloride may be an oxidizing atmosphere. In this case, the average volume concentration of oxygen in the gas containing hydrogen chloride is preferably 0.1 to 24% by volume, more preferably 5 to 24% by volume, still more preferably 10 to 24% by volume, and particularly preferably 15 to 24% by volume. Note that the average volume concentration of oxygen means the average value of the oxygen concentration in the reaction apparatus from the start point to the end point of the contact time. The gas containing hydrogen chloride may contain oxygen, nitrogen, carbon dioxide, etc. in addition to hydrogen chloride.

[0036] When using hydrogen chloride generated by burning chlorine-containing waste, the hydrogen chloride may be generated by heating (burning) together with woody biomass ash in a reaction system for heating the woody biomass ash, or a separate reaction system for generating hydrogen chloride may be provided separately from the reaction system for heating the woody biomass ash, and the hydrogen chloride may be generated in the said reaction system.

[0037] When heating a chlorine-containing waste together with woody biomass ash in a reaction system for heating the woody biomass ash to generate hydrogen chloride, the chlorine-containing waste and the woody biomass ash may be simultaneously charged into the reaction system, or they may be charged separately.

[0038] Even when heating a chlorine-containing waste together with woody biomass ash in a reaction system for heating the woody biomass ash, a gas containing hydrogen chloride may be introduced as an atmospheric gas.

[0039] The gas containing hydrogen chloride discharged in this step can be recovered, for example, by gas-liquid contact. The hydrochloric acid solution obtained by gas-liquid contact of hydrogen chloride in the discharged gas can be used for washing the woody biomass ash in the second step.

[0040] <Second Step> This step is a step of washing the woody biomass ash after contact with water to remove soluble components.

[0041] This step is a step of making a slurry of the woody biomass ash after contact and water in a certain amount and stirring for a time sufficient to elute alkali metal salts such as potassium chloride in the woody biomass ash. This step is usually carried out after cooling the woody biomass ash after contact to a temperature of 100°C or lower (for example, room temperature of 25°C).

[0042] The stirring of the woody biomass ash after contact and water can be carried out using a commonly used stirring device. The stirring of the woody biomass ash after contact and water may be carried out while heating if necessary.

[0043] In the stirring of the woody biomass ash after contact with water, the mass ratio of water to the woody biomass ash after contact (mass of water / mass of the woody biomass ash after contact) is preferably 1 to 20. When the mass ratio is less than 1, the ionic strength of water becomes too high, the elution amount of potassium chloride tends to decrease, and the viscosity of the slurry becomes too high, resulting in a tendency for the transportability to decrease. Also, when the mass ratio exceeds 20, a large amount of water is required, so the operating cost tends to increase. The mass ratio is more preferably 3 to 15, and even more preferably 5 to 12.

[0044] The water for washing the woody biomass ash may be hydrochloric acid water containing hydrogen chloride. By using hydrochloric acid water, it becomes possible to more sufficiently elute alkali metal salts such as potassium chloride in the woody biomass ash. The concentration of the hydrochloric acid water is not particularly limited, but may be 0.01 to 2 mol / L. The hydrochloric acid water may be a diluted commercially available hydrochloric acid water. Also, the hydrochloric acid water may contain hydrochloric acid water obtained by bringing the hydrogen chloride in the gas discharged in the first step into gas-liquid contact.

[0045] The production method of the present embodiment may further include a step of separating insoluble woody biomass ash and soluble components to obtain low-potassium woody biomass ash. The separation of the insoluble woody biomass ash and the soluble components can be performed by filtration. Also, the residue solid content obtained by filtration may be subjected to a drying treatment. When performing the drying treatment, the conditions can be, for example, 20 to 300°C for 0.1 to 100 hours.

[0046] The low-potassium woody biomass ash produced by the production method of the present embodiment has a sufficiently reduced potassium content, so it can be used as a cement raw material.

[0047] [Method for Reducing Potassium in Woody Biomass Ash] A method for reducing potassium in woody biomass ash according to one embodiment includes a first step of heating the woody biomass ash at 700 to 1100°C and bringing the woody biomass ash into contact with a gas containing hydrogen chloride, and a second step of washing the woody biomass ash after the contact with water to remove soluble components. The average volume concentration of hydrogen chloride in the gas containing hydrogen chloride is 0.01 to 10% by volume. According to this potassium reduction method, it is possible to reduce the amount of hardly soluble potassium incorporated in the aluminosilicate (crystal) structure of the woody biomass ash without leaving organic substances in the final product by using a low-concentration hydrogen chloride gas. Note that the woody biomass ash, reaction apparatus, etc. used in the method for reducing potassium in woody biomass ash are the same as those used in the method for producing low-potassium woody biomass ash. Therefore, duplicate explanations are omitted here.

[0048] [Method for manufacturing cement] A method for manufacturing cement according to one embodiment includes a step of using the low-potassium woody biomass ash produced by the above-described manufacturing method as a cement raw material. Examples of the step of using the low-potassium woody biomass ash as a cement raw material include a step of mixing the low-potassium woody biomass ash with a cement raw material such as limestone, and a step of feeding the low-potassium woody biomass ash together with a cement raw material such as limestone into a kiln.

[0049] [Method for recycling woody biomass ash as cement resource] A method for recycling woody biomass ash as a cement resource according to one embodiment uses the low-potassium woody biomass ash produced by the above-described manufacturing method as a cement raw material. Since the amount of potassium in the low-potassium woody biomass ash produced by the above-described manufacturing method is sufficiently reduced, it can be used as a cement raw material, enabling the recycling of the woody biomass ash as a cement resource.

Examples

[0050] Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited thereto.

[0051] <Preparation of Reaction Apparatus> The production of low-potassium woody biomass ash was carried out using the following reaction apparatus. Figure 1 is a schematic diagram showing the reaction apparatus used in the examples. The reaction apparatus 100 shown in Figure 1 includes a heating unit 20 and an exhaust gas trap unit 30. The heating unit 20 is mainly composed of a ceramics tube 22 filled with woody biomass ash 26 to be heated and a tubular furnace 24 for heating the ceramics tube 22. The ceramics tube 22 has a connecting tube 44 connecting to the hydrogen chloride generation unit 10 and a gas discharge tube 46 for discharging the gas in the tubular furnace 24. Hydrogen chloride is introduced into the ceramics tube 22 from the connecting tube 44. When using hydrogen chloride generated by burning chlorine-containing waste, hydrogen chloride is generated from the hydrogen chloride generation unit 10 and introduced into the ceramics tube 22 from the connecting tube 44. The exhaust gas trap unit 30 is mainly for trapping hydrogen chloride discharged from the gas discharge tube 46.

[0052] <Production of Low-Potassium Woody Biomass Ash> (Example 1) Forty grams of woody biomass ash (proportion of fly ash: 100% by mass) was filled into a ceramic tube (outer diameter φ50 mm, inner diameter φ42 mm), and the ceramic tube filled with woody biomass ash was placed in a tubular furnace in the heating section. The inside of the tubular furnace was set to an air atmosphere, and the tubular furnace was heated to 1000°C. After the tubular furnace reached 1000°C, a gas containing hydrogen chloride with a volume concentration of hydrogen chloride of 1% by volume (volume concentration of oxygen: 21% by volume), which was prepared using hydrogen chloride generated by dropping concentrated hydrochloric acid into concentrated sulfuric acid and air, was introduced into the tubular furnace at a flow rate of 15 L / hour. The starting point of the contact time between the woody biomass ash and the gas containing hydrogen chloride was set as the time when the gas containing hydrogen chloride was introduced, and the woody biomass ash and the gas containing hydrogen chloride were brought into contact for 120 minutes. Then, the tubular furnace was cooled to room temperature (25°C), and the woody biomass ash after contact was recovered. Water was added to the recovered woody biomass ash after contact so that the mass ratio of water to the woody biomass ash after contact (mass of water / mass of woody biomass ash after contact) was 10, and the mixture was stirred for 30 minutes to remove the soluble components. Then, the residue solid content was recovered by filtration to obtain the low-potassium woody biomass ash of Example 1. The potassium content of the woody biomass ash before contact and the potassium content of the low-potassium woody biomass ash were measured respectively, and based on the following formula, the potassium removal rate was calculated. The results are shown in Table 1.

[0053] Potassium removal rate (%) = [(absolute amount of K 2 O in woody biomass ash (g) - absolute amount of K 2 O in low-potassium woody biomass ash (g)) / absolute amount of K 2 O in woody biomass ash (g)] × 100

[0054] (Examples 2 to 7 and Comparative Example 1) Except that the contact treatment conditions of Example 1 in Table 1 were changed to the contact treatment conditions of Examples 2 to 7 and Comparative Example 1 in Table 1, in the same manner as in Example 1, the low-potassium woody biomass ash of Examples 2 to 7 and Comparative Example 1 was obtained. In the same manner as in Example 1, the potassium removal rates of Examples 2 to 7 and Comparative Example 1 were calculated. The results are shown in Table 1.

[0055]

Table 1

[0056] As shown in Table 1, the production methods of Examples 1 to 7 in which the lignocellulosic biomass ash is heated at 800 °C or 1000 °C can sufficiently reduce the potassium content of the lignocellulosic biomass ash using a low concentration of hydrogen chloride gas as compared with the production method of Comparative Example 1 in which the lignocellulosic biomass ash is heated at 650 °C. It was also confirmed that in the production methods of Examples 1 to 7, when the lignocellulosic biomass ash was contacted at the same temperature, the potassium removal rate of the lignocellulosic biomass ash tended to increase as the contact time became longer.

[0057] (Examples 8, 9) The post-contact lignocellulosic biomass ash obtained under the contact treatment conditions of Example 4 and Example 7 was each used to remove soluble components using hydrochloric acid water containing hydrogen chloride (hydrochloric acid water adjusted to a concentration of 0.056 mol / L using exhaust gas trap water obtained by gas-liquid contact of the excess hydrogen chloride gas discharged from the tubular furnace). Thereafter, the residue solid content was recovered by filtration to obtain low-potassium lignocellulosic biomass ash of Example 8 and Example 9. In the same manner as in Example 1, the potassium removal rates of Example 8 and Example 9 were calculated. The results are shown in Table 2. For comparison, the potassium removal rates of Example 4 and Example 7 are also shown in Table 2. Chemicalization

[0058] [Table 2]

[0059] As shown in Table 2, from the comparison between Example 4 and Example 8 and the comparison between Example 7 and Example 9, it was found that the potassium removal rate was improved by washing the post-contact lignocellulosic biomass ash with hydrochloric acid water. [Explanation of Signs]

[0060] 10... Hydrogen chloride generation section, 20... Heating section, 22... Ceramic tube, 24... Tubular furnace, 26... Lignocellulosic biomass ash, 30... Exhaust gas trap section, 44... Connecting pipe, 46... Gas discharge pipe, 100... Reactor.​

Claims

1. A method for producing low-potassium woody biomass ash in which the amount of potassium in the woody biomass ash is reduced, comprising: a first step of bringing the woody biomass ash into contact with a gas containing hydrogen chloride at 700 to 1100 ° C in a gas atmosphere containing hydrogen chloride; a second step of washing the woody biomass ash after contact with water to remove soluble components; and the average volume concentration of hydrogen chloride in the gas containing hydrogen chloride is 0.1 to 5% by volume, in the second step, the water is hydrochloric acid water containing hydrogen chloride, A method for producing low-potassium woody biomass ash.

2. The first step is a step of heating the woody biomass ash at 700 to 1100 ° C, introducing the gas containing hydrogen chloride, and bringing the woody biomass ash into contact with the gas containing hydrogen chloride. The method for producing low-potassium woody biomass ash according to claim 1.

3. In the first step, the contact time between the woody biomass ash and the gas containing hydrogen chloride is 1 to 120 minutes. The method for producing low-potassium woody biomass ash according to claim 1 or 2.

4. The gas containing hydrogen chloride further contains oxygen, and the average volume concentration of oxygen in the gas containing hydrogen chloride is 0.1 to 24% by volume. The method for producing low-potassium woody biomass ash according to any one of claims 1 to 3.

5. The proportion of fly ash in the woody biomass ash is 60% by mass or more. The method for producing low-potassium woody biomass ash according to any one of claims 1 to 4.

6. In the second step, the mass ratio of the water to the woody biomass ash after contact is 1 to 20. The method for producing low-potassium woody biomass ash according to any one of claims 1 to 5.

7. The hydrochloric acid water contains hydrochloric acid water obtained by bringing hydrogen chloride in the gas discharged in the first step into gas-liquid contact. The method for producing low-potassium woody biomass ash according to any one of claims 1 to 6.

8. A method for reducing potassium in woody biomass ash, comprising: a first step of bringing the woody biomass ash into contact with a gas containing hydrogen chloride at 700 to 1100 ° C in a gas atmosphere containing hydrogen chloride; a second step of washing the woody biomass ash after contact with water to remove soluble components; and the average volume concentration of hydrogen chloride in the gas containing hydrogen chloride is 0.1 to 5% by volume, In the second step, the water is hydrochloric acid water containing hydrogen chloride. Method for reducing potassium in woody biomass ash. Claim 9 The first step is a step of heating the woody biomass ash at 700 to 1100 °C, introducing the gas containing hydrogen chloride, and bringing the woody biomass ash into contact with the gas containing hydrogen chloride. The method for reducing potassium in woody biomass ash according to claim 8. Claim 10 A step of using the low-potassium woody biomass ash produced by the production method according to any one of claims 1 to 7 as a cement raw material is provided. Method for producing cement. Claim 11 Using the low-potassium woody biomass ash produced by the production method according to any one of claims 1 to 7 as a cement raw material. Method for recycling woody biomass ash as cement resources.

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