WO2019009303A1

WO2019009303A1 - Solid waste treatment method

Info

Publication number: WO2019009303A1
Application number: PCT/JP2018/025263
Authority: WO
Inventors: 清隆吉井; 有記長尾; 吉田　洋一; 崇宏関
Original assignee: 宇部興産株式会社
Priority date: 2017-07-04
Filing date: 2018-07-03
Publication date: 2019-01-10
Also published as: JPWO2019009303A1

Abstract

In a solid waste treatment method according to the present invention, incinerated ash and a phosphorus source are mixed and heated at 600-1200ºC. Examples of the phosphorus source include phosphorus-containing waste and phosphorus-containing compounds, and it is preferable that the phosphorus source be phosphorus-containing waste. In particular, it is preferable that the phosphorus source be at least one type selected from a group consisting of sewage-sludge-based phosphorus-containing waste, agriculture/fishery-based phosphorus-containing waste, industrial phosphorus-containing waste, and food-based phosphorus-containing waste. It is also preferable that the incinerated ash be coal ash generated by combusting coal alone or a mixture of coal and biomass.

Description

Solid waste disposal method

The present invention relates to a method of treating solid waste.

As a method of suppressing harmful trace element elution from incinerated ash, a method of adding a drug, a method of extracting with a solvent, a method of heat treatment and the like are known. Among them, although a method of adding a drug is widely used as a method capable of suppressing elution of harmful trace elements with relatively high productivity, since the added drug squeezes the manufacturing cost, it has been an economical processing method so far. Had a challenge.

For example, Patent Document 1 describes a method of insolubilizing boron and fluorine by mixing a phosphoric acid compound and a calcium compound with a solid waste containing boron and fluorine.

Patent Document 2 describes a treatment method in which water, silica gel and a phosphoric acid-based heavy metal fixing agent are added to heavy metal-containing ash and kneaded. The same document discloses an example of reducing the elution amount of lead.

In Patent Document 3, phosphorous acid and / or hypophosphorous acid is added to solid waste, and heated to 300 ° C. or less to cause harmful metals such as lead in solid waste and organic chlorinated compounds. A process for the treatment of solid waste to be detoxified is described.

Patent Document 4 describes a method for producing a porous sintered body by firing a material to be fired containing one or two or more wastes selected from the group consisting of incineration ash, sludge, and construction generated soil. It is described that the temperature at the time of the baking is set to 650 to 1000 ° C., and the elution amount of hexavalent chromium can be made equal to or less than the environmental standard value by this manufacturing method.

Japanese Patent Application Publication No. 2007-181758 Unexamined-Japanese-Patent No. 10-174952 US6137027A JP, 2009-132566, A

However, with respect to the techniques described in Patent Documents 1 to 3, there is a need for an insolubilizing method of harmful elements capable of insolubilizing various harmful elements at lower cost.
Furthermore, as described in Patent Document 3, phosphorous acid and / or hypophosphorous acid is added to solid waste and heated to 300 ° C. or lower, as in Patent Document 4, incineration ash or sludge alone. In the case of firing only, the harmful metal elution suppressing effect is not sufficient.

In addition, due to the tightness of waste disposal sites in Japan, effective use of incineration ash derived from household waste and industrial waste, which is increasing yearly, is desired. As an example of the effective use of incineration ash, reuse and landfill use in civil engineering projects such as building materials can be mentioned. However, these projects are premised on reusing waste as a material that is used outdoors for a long time, so there is concern about environmental pollution due to elution of harmful trace elements contained in incineration ash. Therefore, in order to promote the effective use of incinerator ash, it is necessary to develop a method that has a high effect of suppressing the elution of harmful trace elements.

The present invention has been made in view of the above problems, and contains harmful trace elements which adversely affect the environment, such as boron, arsenic, selenium, fluorine, hexavalent chromium, lead, mercury and / or cadmium and the like. An object of the present invention is to provide a method for treating incineration ash which reduces the elution of harmful trace elements from the incineration ash. Specifically, it is an object of the present invention to provide a method for treating incineration ash which has higher productivity than before and can reduce the elution amount of these harmful trace elements to an environmental standard value or less defined in the Soil Contamination Countermeasures Law.

The present invention solves the above-mentioned problems by providing a method for treating solid waste comprising the steps of mixing incineration ash and a phosphorus source and heating the mixture at 600 ° C. or more and 1200 ° C. or less.

Further, the present invention comprises a step of mixing incineration ash and a phosphorus source and heating the mixture at 600 ° C. to 1200 ° C., boron, arsenic, selenium, fluorine, hexavalent chromium, lead contained in the incineration ash or phosphorus source And a method of inhibiting the elution of at least one element of the group consisting of mercury and cadmium.

The present invention will be described below based on its preferred embodiments. However, the present invention is not limited to the following embodiments.
This embodiment is a method for treating solid waste, which has a step of mixing incineration ash and a phosphorus source and heating the mixture at 600 ° C. or more and 1200 ° C. or less. Solid waste refers to incinerated ash in this embodiment.

Examples of the incineration ash to be treated in the present embodiment include incineration ash of general waste discharged from a household, incineration ash generated from an industrial waste incineration facility, or fly ash or clinker discharged from a coal-fired power plant. Examples include coal ash such as ash. The coal ash may be incineration ash generated by burning coal alone, or may be incineration ash generated by burning a mixture of coal and biomass. Biomass is organic matter derived from organisms, such as agricultural products and timber products. Specifically, agricultural waste such as rice straw, firs and pheasant, agricultural chips such as lice and wood pellets, thinning materials, waste wood for construction And other timber-derived materials. As a mixing ratio in the case of burning a mixture of coal and biomass, a mass ratio of coal ash: biomass is 1: 0.01 to 2.0.

For example, when the incineration ash contains a large amount of elements such as fluorine and boron specified in the Soil Contamination Countermeasures Act, in addition to heavy metal elements such as arsenic, selenium, lead, hexavalent chromium, mercury and cadmium. When the elution amount is measured by a method according to Environment Agency Notification No. 46 as in the examples described later, the environmental standard value described in the following examples may be exceeded. Therefore, if the incineration ash is discarded as it is, these elements may leach into the environment and contribute to environmental pollution. The treatment method of the present invention is to reduce the elution amount from incineration ash with respect to at least one element of the group consisting of the above eight elements being regulated. The treatment method of the present embodiment is particularly effective for the elution suppression of boron, fluorine and / or hexavalent chromium.

The total amount (A) of arsenic, chromium and boron in 10 g of incinerated ash is generally 0.1 mg or more and 50 mg or less, and from the viewpoint of the effectiveness of the treatment method of this embodiment, 1.0 mg or more and 30 mg or less More preferable. The total amount of arsenic, chromium and boron in 10 g of incinerated ash is measured by inductively coupled plasma mass spectrometry (ICP-MS) or the like for any of the elements. When measuring by ICP-MS, add sulfuric acid, nitric acid and hydrofluoric acid to the sample and perform quantitative analysis as a test solution diluted with ultrapure water after pressurized acid decomposition in a closed container at 215 ° C for 16 hours .

Further, the amount of phosphorus in 10 g of the incinerated ash is not particularly limited, and generally, 1 mg to 100 mg can be mentioned. The amount of phosphorus here is the amount of phosphorus atom conversion.
The amount of phosphorus in 10 g of incinerated ash is measured by the following method.
The residue obtained by heating the sample at 900 ° C. for 3 hours is subjected to fluorescent X-ray analysis (XRF), and the measured value of phosphorus pentoxide is converted to the amount of phosphorus alone.

The amount of calcium in 10 g of the incinerated ash is also not particularly limited, but, for example, 10 mg to 5000 mg, particularly 100 mg to 3000 mg is a general range. When the incineration ash is coal ash, the preferred amount of calcium in 10 g of incineration ash is 10 mg to 500 mg, and in the case where the incineration ash is waste incineration ash, the preferred amount of calcium in 10 g of incineration ash is 500 mg to 5000 mg .
The amount of calcium in 10 g of incinerated ash is measured by the following method.
The residue is heated at 900 ° C. for 3 hours and the residue is subjected to X-ray fluorescence analysis (XRF) and calcium oxide measurements are converted to calcium alone.

In the present embodiment, any of phosphorus-containing waste and phosphorus-containing compounds can be used as a phosphorus source to treat incineration ash.

As a phosphorus containing compound, the inorganic compound containing phosphorus is preferable. For example, condensed phosphoric acid (also called polyphosphoric acid), phosphoric acid (H ₃ PO ₄ ), phosphorous acid (H ₃ PO ₃ ), hypophosphorous acid (H ₃ PO ₂ ), phosphonic acid (H ₂ PHO ₃₎ And at least one phosphorus-containing compound selected from the group consisting of phosphinic acids (HPH ₂ O ₂ ) and their salts and their hydrates. Such salts include, for example, alkali metal salts and alkaline earth metal salts such as calcium and magnesium salts. These phosphorus-containing compounds can be used alone or in combination of two or more.

The phosphorus-containing compound used in the present embodiment is preferably polyphosphate, sodium polyphosphate, potassium polyphosphate, calcium polyphosphate, metaphosphate, sodium metaphosphate, potassium metaphosphate, calcium metaphosphate, pyrophosphate, sodium pyrophosphate, pyrophosphate Potassium, calcium pyrophosphate, pentasodium triphosphate, pentapotassium triphosphate, sodium dihydrogenphosphate, disodium hydrogenphosphate, sodium phosphate, potassium dihydrogenphosphate, dipotassium hydrogenphosphate, potassium phosphate, phosphorus Magnesium acid, calcium phosphate, calcium monohydrogen phosphate, calcium dihydrogen phosphate, sodium phosphite, potassium phosphite, calcium phosphite, sodium hypophosphite, sodium hypophosphite, potassium hypophosphite, calcium hypophosphite, phosphonic acid Sodium, potassium phosphonate, sodium phosphinate, calcium phosphinate potassium and phosphinic acid as well as their hydrates and the like. More preferably, it is at least one selected from the group consisting of pentapotassium triphosphate, polyphosphate, polyphosphate and hypophosphite. Still more preferably, polyphosphoric acid, sodium polyphosphate, pentapotassium triphosphate, phosphoric acid, potassium dihydrogenphosphate, dipotassium hydrogen phosphate, tripotassium phosphate, sodium phosphite, calcium hypophosphite and sodium phosphinate As well as their hydrates. These phosphorus-containing compounds can be used alone or in combination of two or more.

The phosphorus-containing waste used in the present embodiment broadly includes phosphorus-containing waste. The phosphorus-containing waste includes sewage sludge-based phosphorus-containing waste, agricultural and fishery-based phosphorus-containing waste, industrial phosphorus-containing waste, and food-based phosphorus-containing waste. Sewage sludge-based phosphorus-containing wastes include general sewage sludge and industrial sewage sludge. The general sewage sludge includes sewage sludge generated at a sewage treatment plant that processes domestic wastewater. Examples of industrial sewage sludge include sewage sludge generated in a sewage treatment facility when wastewater and waste liquid from a factory such as a food factory or a chemical factory is treated in a sewage treatment facility in the factory. Sewage sludge that treats domestic wastewater and sewage treatment facilities that treat industrial wastewater discharged from food factories etc. decompose and adsorb various substances that cause environmental pollution contained in wastewater by microorganisms, and then water Purify. In the process of purification, the dead bodies of microorganisms gather and precipitate and become sludge. These sludges contain a large amount of phosphorus. The agricultural and fishery-based phosphorus-containing wastes include animal-derived wastes such as meat and bone meal of livestock and fish, livestock excrement, and plant-derived wastes such as wheat straw. Industrial-use phosphorus-containing wastes include zinc phosphate chemical conversion treatment process discharged sludge, cleaning solutions for processing or degreasing processes of electronic parts and printed circuit boards, and the like. Examples of the food-based phosphorus-containing waste include okara, soy sauce cake, and leftovers. These may be used alone or in combination of two or more.

In particular, the treatment method of the present invention preferably uses phosphorus-containing waste as a phosphorus source. Phosphorus-containing wastes are generally traded for reverse payment, so increasing the amount of phosphorus-containing waste used in the present invention has the advantage of lowering the cost of treating incineration ash. Furthermore, many phosphorus-containing wastes themselves also have combustion heat, and this combustion heat also has the effect of reducing the energy cost during heat treatment with incineration ash.
In particular, by heating the mixture of incineration ash and phosphorus-containing waste at 600 ° C. or more and 1200 ° C. or less, a suitable balance of the amount of calcium and phosphorus in the mixture of incineration ash and phosphorus-containing waste can be obtained. As a result, in the incinerator obtained, the elution amount of boron, hexavalent chromium and / or arsenic can be made low. In this case, the reduction of the elution amount is superior not only to the elution amount from coal ash alone but also to the elution amount from phosphorus-containing waste alone incinerator.
From these viewpoints, the phosphorus-containing waste is preferably at least one selected from sewage sludge-based phosphorus-containing waste, agro-fishery-based phosphorus-containing waste and industrial phosphorus-containing waste, more preferably a sewage sludge-based waste. Phosphorus-containing waste and / or agro-fishery-based phosphorus-containing waste, particularly preferably general sewage sludge (referred to simply as “sewage sludge” in the following embodiment), industrial sewage sludge (only in the following embodiment “industrial sludge” And at least one selected from meat and bone meal. One of the most preferable forms in terms of reducing the elution amount of boron, hexavalent chromium and arsenic is general sewage sludge or a combination of industrial sewage sludge and meat and bone meal. These wastes may be any of water-containing matter, dried matter and heated matter.

For example, as shown in Comparative Examples 4, 5, 6, 13, 15, 16 and 17 described later, the phosphorus-containing waste used in the present invention is not mixed with incineration ash alone and is 600 ° C. or more and 1200 ° C. or less When the heat-treated product is heated according to the above, the elution amount of the soil environment-based target element such as boron, arsenic, hexavalent chromium or phosphorus may be a certain amount or more. As shown in Examples described later, the present invention can reduce the elution amount by mixing phosphorus-containing waste with incineration ash and heating the mixture at 600 ° C. or more and 1200 ° C. or less to form a heat-treated product. It is possible. Therefore, the present invention includes, for example, mixing incineration ash and phosphorus-containing waste and heating the mixture at 600 ° C. or more and 1200 ° C. or less, such as boron, arsenic, hexavalent chromium or phosphorus from phosphorus-containing waste. The present invention may provide a method for suppressing the elution of the target element of the soil environment standard.

The phosphorus content in the phosphorus-containing waste used in the present invention largely changes depending on the form and liquid content of the phosphorus-containing waste used, from the viewpoint that the effects of the present invention are more significantly exhibited. For example, general dewatered sludge has a moisture content of 80-90% by mass, but not only such water-containing products called dewatered sludge but also dried products from which water has been removed and organic matter at 200 to 900 ° C. Any of the decomposed sludge heating products can be used. Therefore, although the usage mode of the phosphorus-containing waste is not particularly limited, some of them contain a large amount of water and organic substances, and thus P ₂ in the fluorescent X-ray analysis (XRF) measured while heating at 900 ° C. for 3 hours. The value in terms of O ₅ is preferably 5 to 60% by mass, and more preferably 10 to 40% by mass, with respect to the mass of phosphorus-containing waste heated at 900 ° C. for 3 hours. The heating here is performed under an air atmosphere. When the phosphorus content is high, the elution suppression effect of the present invention is reduced. On the other hand, when the amount is small, problems such as a large decrease in productivity occur. Further, by mixing these wastes with incineration ash and heating them, the elution amount of harmful trace elements contained in the incineration ash and phosphorus-containing waste can be suppressed, and the waste can be reduced.

In the present invention, the incineration ash is mixed with a phosphorus source to treat the incineration ash. The addition amount of the phosphorus source used at this time is 0.001 mass part 60 mass in phosphorus element (P) conversion with respect to 100 mass parts of incinerated ash from the viewpoint that the elution inhibitory effect of harmful trace element appears more significantly. The content is preferably not more than 0.01 parts by weight and not more than 40 parts by weight, more preferably 0.05 parts by weight and 20 parts by weight, and still more preferably 0.1 parts by weight and 10 parts by weight. It is more preferable that it is the following. By setting the addition amount of the phosphorus source to 0.001 parts by mass or more, particularly 0.01 parts by mass or more, the effect of suppressing elution of harmful trace elements is sufficiently exhibited. Further, by setting the addition amount of the phosphorus source to 60 parts by mass or less, it is easy to make the elution amount of phosphorus from the treated material of the incineration ash equal to or less than the environmental standard value.
When the phosphorus source mentioned here is phosphorus-containing waste, the amount of phosphorus in the waste can be measured by the following method.
The residue obtained by heating the sample at 900 ° C. for 3 hours is subjected to fluorescent X-ray analysis (XRF), and the measured value of phosphorus pentoxide is converted to the amount of phosphorus alone.

Furthermore, from the viewpoint of further enhancing the elution amount reduction effect of arsenic, hexavalent chromium and boron, phosphorus in the mixture of the incineration ash and the phosphorus source relative to the total amount of arsenic, chromium and boron in the incineration ash The amount is preferably 1 times by mass or more, more preferably 10 times by mass or more, and particularly preferably 15 times by mass or more. On the other hand, the amount of phosphorus in the mixture of the incineration ash and the phosphorus source is 400 mass times or less with respect to the total amount of arsenic, chromium and boron in the incineration ash, It is preferable because it is easy to make the elution amount of phosphorus equal to or less than the environmental standard value, and 300 mass times or less is more preferable. When the mixture contains phosphorus-containing components other than incineration ash and phosphorus-containing waste in addition to the phosphorus-containing components of incineration ash and phosphorus-containing waste, the amount of phosphorus in the mixture referred to here The amount of phosphorus is also included. In particular, when the incineration ash is coal ash and general sewage sludge, the amount of phosphorus in the mixture of the incineration ash and the phosphorus source is 18 with respect to the total amount of arsenic, chromium and boron in the incineration ash. It is still more preferable that the amount is equal to or more than the mass ratio in terms of reducing the amount of elution of arsenic.

The amount of calcium is also important in order to enhance the elution suppression effect of arsenic, hexavalent chromium and boron in the present embodiment. For example, the amount of calcium in the mixture of incineration ash and phosphorus source is preferably at least 10 times by mass, preferably at least 30 times by mass, the total amount of arsenic, chromium and boron in the incineration ash Is particularly preferred. In particular, when the amount of calcium in the mixture of incineration ash and phosphorus source is 75 mass times or more relative to the total amount of arsenic, chromium and boron in incineration ash, the elution suppression effect of arsenic is very excellent. It is preferable because the

Although the reason why the amount of calcium in the mixture of incineration ash and phosphorus source is important is not clear, the inventor speculates that it is the following reason.
For example, in a heated mixture of incineration ash and a phosphorus source, phosphorus and calcium form calcium phosphate during heat treatment, and this covers the surface of the mixture, whereby the elution of boron, arsenic and hexavalent chromium is caused. It is thought that the suppression effect is easy to obtain. Also, arsenic is considered to be water insoluble calcium arsenate which binds to calcium during heat treatment.
It is preferable that calcium in the mixture of the incineration ash and the phosphorus source is present in a certain amount or more with respect to the total amount of arsenic, chromium and boron in the incineration ash, but it is preferable to exist more than a certain amount. It may affect the elution suppression of chromium. From the viewpoint of effectively suppressing hexavalent chromium, the amount of calcium in the mixture of the incineration ash and the phosphorus source is 1000 mass times or less with respect to the total amount of arsenic, chromium and boron in the incineration ash It is more preferably 800 mass times or less, and particularly preferably 450 mass times or less.

In particular, when the incineration ash is coal ash, the amount of calcium in the mixture of the coal ash and the phosphorus source is 10 times by mass to 800 times by mass the total amount of arsenic, chromium and boron in the incineration ash Is more preferably 30 to 450 mass times, and most preferably 445 mass times or less.
When the incineration ash is general waste incineration ash, the amount of calcium in the mixture of general waste incineration ash and the phosphorus source is 400 mass times the total amount of arsenic, chromium and boron in the incineration ash It is preferable that it is 1000 mass times or less, and more preferable that it is 600 mass times or more and 800 mass times or less.

The amount of calcium in the above mixture includes calcium content of incineration ash and phosphorus-containing waste, as well as calcium content of the calcium-containing component if the mixture contains calcium addition components other than incineration ash and phosphorus-containing waste. Also includes the amount of
For example, the calcium amount of the phosphorus source can be measured by the following method.
The residue is heated at 900 ° C. for 3 hours and the residue is subjected to X-ray fluorescence analysis (XRF) and calcium oxide measurements are converted to calcium alone.

Furthermore, the mass ratio (Ca / P) of the amount of calcium in the mixture to the amount of phosphorus in the mixture is 0.5 or more, which is particularly effective for the elution of boron and arsenic in the resulting treated product. It is preferable because it can be reduced, and in particular, it is preferable that it is 1 or more because the effect of reducing the elution amount of boron and arsenic is the highest. On the other hand, the mass ratio (Ca / P) of the amount of calcium in the mixture to the amount of phosphorus in the mixture is preferably 50 or less because the elution amount of hexavalent chromium can be more effectively reduced, and particularly 30 It is preferable that it is the following.

The amount of phosphorus (element P equivalent amount) in the mixture of incineration ash and phosphorus source is not particularly limited, but it is 0.1 mass% or more and 10 mass% or less and the elution amount of arsenic, hexavalent chromium and boron Is preferable in that it can reduce effectively, and it is particularly preferable that the content is 0.3% by mass or more and 5.0% by mass or less.

The amount of calcium in the mixture of incineration ash and phosphorus source is not particularly limited, but that 0.1 mass% or more and 50 mass% or less can effectively reduce the elution amount of arsenic, hexavalent chromium and boron. In particular, the content is preferably 1.0% by mass or more and 35% by mass or less.

When a phosphorus-containing waste is used as a phosphorus source in the present embodiment, the phosphorus-containing waste and a phosphorus-containing component other than the incineration ash are contained in a mixture of the phosphorus-containing waste and the incineration ash to obtain the above preferable phosphorus amount. You may adjust.
Further, as the above-mentioned phosphorus-containing component, various phosphorus-containing compounds mentioned above can be mentioned, and in particular, sodium phosphate, polyphosphate, sodium polyphosphate, pentapotassium triphosphate, phosphate, potassium dihydrogenphosphate Dipotassium hydrogen phosphate, tripotassium phosphate, sodium phosphite, and hydrates of these, with sodium phosphate being particularly preferred.
The addition amount of phosphorus components other than phosphorus-containing waste and incineration ash is preferably 0.1 to 40 parts by mass with respect to 100 parts by mass of incineration ash as solid content, in 0.5 to 20 parts by mass It is more preferable that

In the present embodiment, the mixture of the phosphorus source and the incineration ash may contain a calcium-containing component and / or a phosphorus-containing component other than the phosphorus source and the incineration ash to adjust to the above-mentioned suitable calcium amount. The phosphorus source in this case is particularly preferably phosphorus-containing waste. Examples of the calcium-containing component include calcium oxide, calcium hydroxide, calcium chloride, calcium carbonate, calcium sulfate, calcium phosphate, and paper sludge ash which is a waste in a paper mill having a large amount of calcium, particularly paper. Sludge ash and calcium oxide are preferred.
The amount of the calcium-containing component other than the phosphorus-containing waste and the incineration ash is preferably 0.1 to 40 parts by mass with respect to 100 parts by mass of the incineration ash as solid content. It is more preferable that

Further, in the present invention, it is preferable to contain a sodium component in the mixture of the phosphorus source and the incineration ash, because the elution amount of boron and / or hexavalent chromium can be reduced particularly in the obtained treated product. The phosphorus source in this case is particularly preferably phosphorus-containing waste. Examples of the sodium component include sodium chloride, sodium hydroxide, sodium carbonate, sodium phosphate and seawater, and sodium chloride, sodium hydroxide and sodium phosphate are particularly preferable. The addition amount of the sodium component is preferably 0.1 to 40 parts by mass, and more preferably 0.5 to 20 parts by mass with respect to 100 parts by mass of the incinerated ash as solid content. In particular, as apparent from the comparison between Example B-4 and B-5, the elution amount of hexavalent chromium can be easily reduced by incorporating a sodium component such as sodium chloride in the mixture of the waste incineration ash and the phosphorus source. It is preferable because it can be done.
Further, as apparent from the comparison of Example C-16 with C-17 and C-18, the treated product of the present embodiment obtained by adding the sodium component to the mixture of phosphorus-containing waste and incineration ash In the above, reduction of the elution amount of boron can also be suppressed.

In the treatment method of the present invention, the method of mixing the incineration ash and the phosphorus source is not particularly limited. For example, a method of physically mixing incineration ash and phosphorus source, a method of impregnating incineration ash with a solution or slurry in which a phosphorus source is dissolved or suspended in a solvent, physically mixing incineration ash and phosphorus source The method of adding a solvent later, etc. are mentioned.

As a solvent to be used, one which can dissolve or suspend a phosphorus source can be used. Examples include aqueous solvents such as water (tap water, distilled water, ion-exchanged water and the like) and seawater, and organic solvents including alcohols such as methanol, ethanol and isopropyl alcohol. The preferred solvent is water. The amount of the solvent used is preferably 5 parts by mass or more and 200 parts by mass or less, and more preferably 10 parts by mass or more and 100 parts by mass with respect to 100 parts by mass of the incinerated ash from the viewpoint More preferably, it is at most parts by mass.

In the present invention, it is preferable to heat treat the mixture after mixing the incineration ash and the phosphorus source to obtain a mixture, from the viewpoint of sufficiently obtaining the elution suppressing effect of harmful trace elements. The method of the heat treatment is not particularly limited, and, for example, a general calciner, a ring furnace, a calciner such as a kiln can be used. The atmosphere for the heat treatment is not particularly limited, and may be, for example, an oxygen-containing atmosphere such as air and oxygen, and an inert gas atmosphere such as nitrogen and argon. From an economic point of view, it is preferable to carry out the heat treatment in air. When heat-processing in air, it is preferable to heat-process, distribute | circulating air from a viewpoint from which the elution inhibitory effect of harmful trace element becomes much more remarkable.

The heat treatment is preferably performed at a temperature that can suppress the elution amount of harmful trace elements from the heat-treated product. As a result of studies by the present inventor, it was found that heating at 600 ° C. or higher can sufficiently suppress the elution amount of harmful trace elements from the heat-treated product. From this point of view, the higher the heating temperature, the more the elution amount of harmful trace elements can be suppressed. Therefore, the heat treatment is preferably performed at 600 ° C. or more (particularly, more than 600 ° C.) 1200 ° C. or less, and more preferably 700 ° C. or more and 1200 ° C. or less.
In particular, when the incineration ash is coal ash, it is more preferably 750 ° C. or more and 1200 ° C. or less, and still more preferably 800 ° C. or more and 1100 ° C. or less from the viewpoint of the elution suppression of hexavalent chromium, arsenic and boron. It is particularly preferable to set the temperature to 850 ° C. or more and 1000 ° C. or less. On the other hand, when the incineration ash is the incineration ash of general waste, the heating temperature is more preferably 600 ° C. or more and 1000 ° C. or less, 650 ° C. or more and 850 ° C. from the viewpoint of the elution suppression of hexavalent chromium, arsenic and boron. It is still more preferable to set it as the following, and it is especially preferable to set it as 700 degreeC or more and 780 degreeC or less.

In the case of coal ash or general waste incineration ash as the incineration ash used in the present invention, the phosphorus source is unburned carbon contained in incineration ash such as coal ash by heat treatment at 600 ° C. or higher, particularly 700 ° C. or higher. It also makes it possible to promote the decomposition of carbon and reduce the unburned carbon content in incineration ash. This is particularly advantageous when the incineration ash is coal ash generated by burning a mixture of biomass and coal, which is a carbon-rich substance. By reducing the unburned carbon content in the incineration ash, it is possible to reduce the amount of cement used, for example, when preparing a filling material for adding cement to coal ash. Moreover, when adding a coal ash at the time of concrete manufacture, carbon float derived from coal ash can be suppressed.

When the heating temperature is in the above-mentioned range, the heat treatment time is preferably 30 minutes to 24 hours, more preferably 1 hour to 10 hours, and still more preferably 1 hour to 5 hours. By heating within the time of this range, the elution amount of harmful trace elements from the heat-treated product can be sufficiently and economically suppressed.

Moreover, it is also preferable to heat the mixture of incineration ash and a phosphorus source previously at 80 degreeC or more and 300 degrees C or less, and then to perform said heat processing. In this way, not only can removal of low boiling point compounds such as water be efficiently performed, but there is also an advantage that decomposition of organic substances in subsequent high temperature heating can be promoted. When the mixture of incineration ash and phosphorus source is heated in advance at 80 ° C. to 300 ° C., the method of the heat treatment and the atmosphere of the heat treatment include the method of heat treatment of the above heat treatment at 600 ° C. to 1200 ° C. And those mentioned above as the heat treatment atmosphere. Moreover, as a heating time in the case of heating the mixture of incineration ash and a phosphorus source previously at 80 degreeC or more and 300 degrees C or less, 15 minutes or more and 10 hours or less are preferable from the point which exhibits the effect by said advantage still higher. More preferably, 30 minutes or more and 5 hours or less.

Further, in the present invention, it may or may not have a granulation step before the above-mentioned heat treatment at 600 ° C., preferably 700 ° C. or more.
Examples of the properties of the heat-treated product after the heat treatment at 600 ° C. or more, preferably 700 ° C. or more described above include powdery matter and granular matter.

By using the treatment method of the present invention as described above, soil pollution measures included in incineration ash which are highly productive, easily industrially and without being influenced by the physical properties, composition and raw materials of incineration ash It is possible to simultaneously reduce the elution amount of a plurality of harmful trace elements defined in the law below the environmental standard value. Specifically, the elution amount of at least one element in the group consisting of boron, arsenic, selenium, fluorine, hexavalent chromium, lead, mercury and cadmium can be reduced, and preferably is included in these groups The elution amount of two or more elements can be reduced, more preferably the elution amount of three or more elements can be reduced, and particularly preferably the elution amounts of boron, arsenic and hexavalent chromium are reduced. Most preferably, the elution amount of all the elements contained in these groups can be reduced.

The heat-treated product obtained by the treatment method of the present embodiment has an effect that elution of harmful trace elements can be suppressed even under a pH environment other than neutral. For example, as a pH environment other than neutral conditions, acidic conditions of pH 2.0 to 5.0 at 25 ° C. and basic conditions of pH 8.0 to 12.0 can be mentioned.

Since the heat-treated product obtained by the treatment method of the present invention suppresses the elution amount of harmful trace elements contained in the heat-treated product even when it is left outdoors, the heat-treated product is an environmentally friendly material. It can be reused. As applications of reuse, for example, building materials such as cement / concrete admixtures, ground improvers, roadbed materials, embankments, backfill materials, civil engineering materials and the like are preferably mentioned.

EXAMPLES The present invention will next be described in detail by way of examples, which should not be construed as limiting the invention thereto. In the following examples and comparative examples, the elution test of boron, arsenic, selenium, fluorine, hexavalent chromium, lead, cadmium and mercury is performed according to the method specified in the Japan Environment Agency Notification No. 46 of 1991. The In addition, the dissolution test of phosphorus was also performed in the same manner as in Japan Environment Agency Notification No. 46. The drying and heating in the incinerator in each of the following examples were all performed in the air. As XRF, ZSX Primus manufactured by Rigaku Corporation was used.
The environmental standard values described in each table are the standard values established by the Ministry of the Environment of Japan. Although not described in any of the following tables, the environmental standard value of mercury is 0.0005 mg / L or less, and the environmental standard value of cadmium is 0.01 mg / L or less.

Specifically, the dissolution test method adopted in each of the following Examples and Comparative Examples in accordance with the Japan Environment Agency Notification No. 46 of 1991 is as follows.
(Preparation method of test solution) It is prepared by the following method according to the method described in the Annex 46 of Japan Environment Agency Notice.
(1) Mix a sample (unit g) and a solvent (hydrochloric acid added to pure water so that the hydrogen ion concentration index is 5.8 or more and 6.3 or less) (unit ml) at a weight volume ratio of 10%, And, the mixture was adjusted to 50 to 500 ml.
(2) Shaker prepared at normal temperature (approximately 20 ° C.) and normal pressure (approximately 1 atm) (previously adjust the shaking frequency to about 200 times per minute and adjust the shaking width to 4 cm or more and 5 cm or less) The mixture was shaken continuously for 6 hours using.
(3) The sample solution obtained by performing the procedure from (1) to (2) is allowed to stand for about 10 minutes to 30 minutes and then centrifuged at about 3,000 rotations per minute for 20 minutes for 20 minutes. The filtrate was collected by filtration with a membrane filter, and the amount necessary for quantification was accurately measured and used as a test solution.
(Method of measuring each element)
Measurements were made using boron, arsenic, selenium, lead, cadmium, mercury, and phosphorus inductively coupled plasma mass spectrometry (ICP-MS). At that time, each element was quantified with a solution obtained by diluting the test solution with 0.3 mol / l nitric acid aqueous solution.
The ICP-MS used is Agilent Technologies Agilent 8000 type.
The fluorine and hexavalent chromium were measured by ion chromatography. At that time, each element was quantified with a solution obtained by diluting the test solution with ultrapure water.
The ion chromatograph used is ICS-2100 manufactured by Thermo Fisher Scientific Inc. + MSQ Plus.

Example A-1
Plant sludge A (water content 88.5 mass%, phosphorus content after heating at 900 ° C for 3 hours 34.4 mass% in terms of P ₂ O _{5 in} XRF) as phosphorus-containing waste 250 g coal ash A 10 g To a mixture to obtain a mixture. Coal ash A is a residue produced by burning coal. Factory sludge A is sewage sludge generated at a wastewater treatment facility of a chemical factory. The obtained mixture was dried at 200 ° C. for 1 hour in a baking furnace (a bench-top electric furnace) and then heat-treated at 900 ° C. for 3 hours. A test solution was obtained from the obtained powdery heat-treated product by the above method, and the concentration of harmful trace elements in the test solution was measured by the above method. The harmful trace elements other than boron, arsenic and hexavalent chromium were mercury <0.0005 mg / L, cadmium <0.001 mg / L, and phosphorus <0.1 mg / L in addition to Table 5. The carbon content in elemental analysis (decomposition at 1150 ° C.) in the heat-treated product was below the detection limit (<0.01 mass%).

[Examples A-2 to A-20]
In Example A-1, conditions relating to the type of incineration ash, the type of phosphorus-containing waste, the amount of phosphorus-containing waste used, and / or the temperature of heat treatment after drying are as shown in Table 1 below. changed. Moreover, about the example described as "annular furnace" in the term of the shape of a furnace, the baking furnace was changed from the table-top electric furnace to the annular electric furnace, and it heat-processed, distribute | circulating air. I baked it. The other conditions were the same as in Example A-1.
In Table 1, the meat-and-bone powder used had a moisture content of 13% by mass and a phosphorus content after heating at 900 ° C. for 3 hours of 31.9% by mass in terms of P ₂ O _{5 in} XRF (the same applies hereinafter).
The plant sludge B used had a water content of 80% by mass and a phosphorus content after heating at 900 ° C. for 3 hours of 18.5% by mass in terms of P ₂ O _{5 in} XRF (the same applies hereinafter).
Coal ash B is a residue produced by burning a mixture of coal and biomass in a mass ratio of 1: 0.05 (the same applies hereinafter).
Coal ash C is a residue produced by burning coal (same below).
Coal ash D is a residue produced by burning coal (the same applies hereinafter).
In the term of amount used (g / g) in Table 1, for example, the description “40 (+ meat and bone meal 2.5) / 10” in Example A-9 is 40 g of factory sludge and 2.5 g of meat and bone meal It shows that it mixed with 10 g of incinerated ash. The same applies to other examples in which meat and bone meal is added to other phosphorus-containing wastes.

[Comparative Examples 1 to 9]
Only one of the incinerated ash and the phosphorus-containing waste was used. The types and amounts of incineration ash or phosphorus-containing waste used are those described in Table 1, temperature of heat treatment after drying, presence or absence of heat treatment (if there is a temperature described, if not, "unbaked" And the shape of the furnace are as shown in Table 1 below. The other conditions were the same as in Example A-1.

The results of the dissolution tests of boron, arsenic and hexavalent chromium in Examples A-1 to A-20 and Comparative Examples 1 to 9 are shown in Table 1.

As shown in Table 1, the elution amounts of harmful trace elements were compared according to the presence or absence of the use of the phosphorus-containing waste, and it was found that the phosphorus-containing waste was obtained by using the phosphorus-containing waste of Example A-1 to A-15. It can be seen that the elution amounts of boron, arsenic and hexavalent chromium can be reduced as compared with Comparative Examples 1 to 3 in which only incinerated ash is used without using. Conversely, when the elution amounts of harmful trace elements were compared according to the presence or absence of the use of coal ash, by using coal ash A of Examples A-1 to A-12, phosphorus-containing waste without using incineration ash It can be seen that the elution amounts of boron, arsenic and hexavalent chromium can be reduced as compared with Comparative Examples 4 and 5 using only. Similarly, it is understood that the elution amounts of boron, arsenic and hexavalent chromium can be reduced by comparing Comparative Example 6 in which only phosphorus-containing waste is used for A-13 to A-15. That is, it can be seen that the heat treatment under the mixture of the incineration ash and the phosphorus-containing waste can reduce the elution amount of the plurality of harmful trace elements more than treating each of them individually.
In addition, comparisons between Examples A-16 to A-20 and the corresponding Comparative Examples show that the elution amounts of boron, arsenic and hexavalent chromium can be reduced as compared with incineration ash alone, as described above. .

Example B-1
As a phosphorus-containing waste, 100 g of factory sludge A was added to 10 g of waste incineration ash to obtain a mixture. Garbage incineration ash is a residue produced by burning general household waste (hereinafter, also simply referred to as “garbage incineration ash”). The mixture was dried at 200 ° C. for 1 hour in a baking furnace and then heat-treated at 900 ° C. for 3 hours. A test solution was obtained from the obtained powdery heat-treated product by the above method, and the concentration of harmful trace elements in the test solution was measured by the above method. The harmful trace elements other than boron, arsenic and hexavalent chromium were mercury <0.0005 mg / L, cadmium <0.001 mg / L and phosphorus <0.1 mg / L. The carbon content in the elemental analysis (decomposed at 1150 ° C.) in the heat-treated product was below the detection limit (<0.01 mass%).

[Examples B-2 to B-7]
The heating temperature, type of phosphorus-containing waste or amount of phosphorus-containing waste in Example B-1 are as shown in Table 2. Except for that point, the same operation as in Example B-1 was performed. In Example B-5, 0.1 part by mass of sodium chloride was further added to 1 part by mass of coal ash to the mixture of coal ash and phosphorus-containing waste.
Sewage sludge A has a moisture content of 84.3% by mass, and a phosphorus content after heating at 900 ° C. for 3 hours of 26.8% by mass in terms of P ₂ O _{5 in} XRF (the same applies hereinafter).
Sewage sludge C has a moisture content of 81.2% by mass, and a phosphorus content after heating at 900 ° C. for 3 hours of 25.7% by mass in terms of P ₂ O _{5 in} XRF (the same applies hereinafter).

[Comparative Examples 10 and 11]
In Comparative Example 10, the same operation as in Example B-1 was performed except that the phosphorus-containing waste was not used in Example B-1. In Comparative Example 11, the same operation as in Example B-3 was performed except that the phosphorus-containing waste was not used in Example B-3.

The results of the dissolution tests of boron, arsenic and hexavalent chromium in Examples B-1 to B-7 and Comparative Examples 10 and 11 are shown in Table 2.

As shown in Table 2, in Examples B-1 to B-7 in which the phosphorus-containing waste was mixed with the waste incineration ash and heated, especially compared with Comparative Examples 10 and 11 in which only the waste incineration ash was heated, 6 It can be seen that the elution of valence chromium is suppressed. The analysis results obtained are shown in Table 3.

Example C-1
In Example A-1, the phosphorus-containing waste used was sewage sludge A and meat-and-bone meal, and the amount of phosphorus-containing waste used was changed as shown in Table 1. The same operation as in Example A-1 was performed except for these points.

[Examples C-2 to C-21]
The process was the same as Example C-1 except that the type of phosphorus-containing waste, the amount of phosphorus-containing waste, or the temperature of heat treatment was changed to the conditions in Table 3. The analysis results obtained are shown in Table 3. Sewage sludge B had a water content of 81.7% by mass, and the phosphorus content after heating at 900 ° C. for 3 hours was 16.5% by mass in terms of P ₂ O _{5 in} XRF. Dry sewage sludge D is granular sludge obtained by flash drying sewage sludge at 200 ° C., and the moisture content is 9 mass%, and the phosphorus content after heating at 900 ° C. for 3 hours is 27 in P ₂ O ₅ conversion in XRF. It was .2 mass%.
Incidentally, _Na 3 PO ₄ as described in the item of additives in Table 3, with sodium phosphate 12-hydrate. PS ash refers to paper sludge ash. All additives were added to the mixture of coal ash and phosphorus-containing waste prior to drying and heat treatment.
In addition, in the analysis of the eluate of the heat-treated product obtained in C-3, harmful trace elements other than boron, arsenic and hexavalent chromium are mercury <0.0005 mg / L, cadmium <0.001 mg / L, lead It was <0.01 mg / L and phosphorus <0.1 mg / L. The carbon content in elemental analysis (decomposition at 1150 ° C.) in the heat-treated product was below the detection limit (<0.01 mass%).
In the eluate of the heat-treated product obtained in Example C-13, harmful trace elements other than boron, arsenic, and hexavalent chromium are mercury <0.0005 mg / L, cadmium <0.001 mg / L, lead It was <0.01 mg / L and phosphorus <0.1 mg / L. The carbon content in elemental analysis (decomposition at 1150 ° C.) in the heat-treated product was below the detection limit (<0.01 mass%).

Comparative Examples 12 to 16
Only one of the incinerated ash and the phosphorus-containing waste was used. The amount of incineration ash or phosphorus-containing waste used was as shown in Table 3, and the temperature of heat treatment after drying was as shown in Table 3 below. The other conditions were the same as in Example C-1.

The results of the dissolution tests of boron, arsenic and hexavalent chromium in Examples C-1 to C-21 and Comparative Examples 12 to 16 are shown in Table 3.

As shown in Table 3, in Examples C-1 to C-25, harmful trace elements, in particular boron and 6 as compared with Comparative Examples 1 and 2 using only coal ash, regardless of the origin of the phosphorus-containing waste It can be seen that the elution of valent chromium can be reduced.

Example D-1
Meat and bone meal (water content 13 wt%, 31.9 wt% of phosphorus content after 3 hours heating at terms _of _P 2 _{O 5} in the XRF at 900 ° C.) as the phosphorus-containing waste by adding 10g coal ash A10g A mixture was obtained. The mixture was dried at 200 ° C. for 1 hour in a baking furnace and then heat-treated at 900 ° C. for 3 hours. A test solution was obtained from the obtained powdery heat-treated product by the above method, and the concentration of harmful trace elements in the test solution was measured by the above method. The harmful trace elements other than boron, arsenic and hexavalent chromium were mercury <0.0005 mg / L and cadmium <0.001 mg / L except as shown in Table 6. The carbon content in the elemental analysis (decomposed at 1150 ° C.) in the heat-treated product was below the detection limit (<0.01 mass%).

[Examples D-2 and D-3]
The same operation as in Example D-1 was performed except that the amount of the meat and bone powder used in the phosphorus-containing waste used in Example D-1 and the heating temperature thereof were the amounts and temperatures shown in Table 3.

Comparative Example 17
It was the same as Example 1 except that incinerated ash was not used.

The results of the dissolution tests of boron, arsenic, and hexavalent chromium in Examples D-1 to D-3 and Comparative Example 17 are shown in Table 4.

As shown in Table 4, it can be seen that by mixing the coal ash A and the meat-and-bone meal and heating at a predetermined temperature, the elution amount of boron and arsenic is reduced compared to the coal ash A alone. In addition, it can also be seen that the elution amount of hexavalent chromium is reduced as compared to a heated product of meat and bone powder alone.

The results of measuring the elution amounts of selenium and fluorine and lead or phosphorus for some of the above-mentioned Examples and Comparative Examples are shown in Tables 5 and 6 below.

As shown in Tables 5 and 6, by mixing the incineration ash and the phosphorus-containing compound and heating the mixture at a predetermined temperature, it is possible to reduce the elution of selenium and fluorine in the incineration ash alone or in the heated product, and heat the sludge alone. It can be seen that the elution of lead or phosphorus in the product can be reduced.

Example E-1
As a phosphorus-containing waste, 40 g of factory sludge A was added to 10 g of coal ash A to obtain a mixture. Coal ash A is a residue produced by burning coal. The mixture was dried at 200 ° C. for 1 hour in a baking furnace and then heat-treated at 900 ° C. for 3 hours. To 1 part by mass of the obtained powdery heat-treated product, 10 parts by mass of an aqueous solution of “extract solution pH” in Table 7 is added instead of the solvent used in the above method, and mixed to prepare a test solution, The concentration of harmful elements was measured for the test solution by the above method. The results are shown in Table 7.
In the "extraction pH" section of Table 7 below, "2.8" refers to a dilute sulfuric acid aqueous solution of pH = 2.8 at 25 ° C, and "11.9" is at 25 ° C. It refers to slaked lime water of pH = 11.9, and “2.1” refers to a dilute sulfuric acid aqueous solution of pH = 2.1 at 25 ° C.

[Examples E-2 to E-19, Comparative Examples 18 to 20]
Example E-1 except that the conditions relating to the type of phosphorus-containing waste, the amount of phosphorus-containing waste, the type of incineration ash, the temperature of heat treatment, or the type of extraction solvent used are changed as shown in Table 7 It was the same as. The results are shown in Table 7.

As shown in Table 7, Examples E-1 to E-16 were all harmful trace elements compared with Comparative Examples (Comparative Examples 18, 19 or 20) using only coal ash A of the corresponding pH. It can be seen that the elution amount can be reduced. Further, it can be seen from Examples E-17 to E-19 that elution standards can be maintained in a wide pH range also when different types of incinerated ash are used.

Next, Examples and Comparative Examples using the phosphorus-containing compound will be described. The mixtures in Tables 8 to 13 below were 10.0 g as 100 parts by mass of incineration ash.
Example F-1
An aqueous solution prepared by dissolving 1.47 parts by mass of 85% phosphoric acid as a phosphorus-containing compound in 40 parts by mass of water was added to 100 parts by mass of coal ash A to obtain a mixture. Coal ash A is a residue produced by burning coal. The mixture was dried at 110 ° C. for 3 hours in a baking furnace and then heat treated at 900 ° C. for 3 hours. A test solution was obtained from the obtained powdery heat-treated product by the above method, and the concentration of harmful trace elements in the test solution was measured by the above method. The results are shown in Table 8. In addition, other harmful trace elements were mercury <0.0005 mg / L, cadmium <0.001 mg / L, lead <0.01 mg / L, and phosphorus 2.2 mg / L. The carbon content in the elemental analysis of the heat-treated product was below the detection limit (decomposed at 1150 ° C.).

Examples F-2 to F-14
The same operation as in Example F-1 was performed except that the phosphorus-containing compound used in Example F-1 and the amount thereof used were changed as shown in Table 8 below. The analysis results of the obtained heat-treated product are shown in Table 8.

Example F-15
An aqueous solution prepared by dissolving 1.25 parts by mass of pentapotassium triphosphate (K ₅ P ₃ O ₁₀ ) as a phosphorus-containing compound in 40 parts by mass of water was added to 100 parts by mass of coal ash E to obtain a mixture. Coal ash E is a residue formed by mixing and burning coal and biomass at a mass ratio of 1: 0.05. The mixture was heat treated at 900 ° C. for 1 hour in a baking furnace. The same analysis as in the above F-1 was performed on the obtained heat-treated product. The analysis results are shown in Table 9.

Examples F-16 to F-23
Example F except using coal ash shown in Table 9 or waste incineration ash instead of the coal ash E used in Example F-15 and replacing the amount of the phosphorus-containing compound with the values shown in Table 9 The same operation as -15 was performed. The analysis results of the obtained heat-treated product are shown in Table 9. Coal ash F-K is a residue produced by burning coal.

[Comparative examples 23 to 27]
Concentrations of harmful trace elements were measured in the same manner as above for the test solutions obtained by the above method for coal ash E, F, G and J used in Examples F-15 to F-23 and waste incineration ash itself. . The results are shown in Table 9.

Examples F-24 to F-29
As the incineration ash, 100 parts by mass of coal ash A was used. In addition, the phosphorus-containing compound and the amount used thereof were changed as shown in Table 10. Furthermore, it heat-processed at the temperature shown in Table 10. Except for these, the operation of Example F-1 was performed. The analysis results of the obtained heat-treated product are shown in Table 10.

[Comparative Examples 28 and 29]
The same operation as in Example F-24 was performed except that the heating temperature in Example F-24 was changed to the heating temperature shown in Table 10. The analysis results of the obtained heat-treated product are shown in Table 10.

[Comparative Examples 30 and 31]
The same operation as in Example F-24 was performed except that the phosphorus-containing compound was not used in Example F-24, and the heating temperature shown in Table 10 was changed. The analysis results of the obtained heat-treated product are shown in Table 10.

Example F-30
100 parts by mass of coal ash A and 10 parts by mass of pentapotassium triphosphate (K ₅ P ₃ O ₁₀ ) as a phosphorus-containing compound were mixed and heat-treated at 900 ° C. for 3 hours. The analysis results of the obtained heat-treated product are shown in Table 11.

[Comparative Examples 33 to 36]
In Example F-30, as shown in Table 11, the same operation as in Example F-30 was performed, except that the phosphorus-containing compound and the heat treatment temperature were changed. The analysis results of the obtained heat-treated product are shown in Table 11.

Example F-31
The same operation as in Example F-30 was performed, except that the phosphorus compound type and the amount thereof were changed. The analysis results of the obtained heat-treated product are shown in Table 11.

Example F-32
An aqueous solution prepared by dissolving 1.25 parts by mass of pentapotassium triphosphate (K ₅ P ₃ O ₁₀ ) as a phosphorus-containing compound in 40 parts by mass of water was added to 100 parts by mass of coal ash A to obtain a mixture. The mixture was heat treated in a baking furnace at 900 ° C. for 1 hour. A test solution was obtained for the obtained powdery heat-treated product by the above method, and the concentration of harmful trace elements in this test solution was measured by the above method. However, 5.0 mmol / L hydrochloric acid aqueous solution (pH 2.3) was used as a solvent to be mixed with the heat-treated product for preparation of a test solution. The analysis results of the obtained heat-treated product are shown in Table 12.

Example F-33
An aqueous solution prepared by dissolving 1.25 parts by mass of pentapotassium triphosphate (K ₅ P ₃ O ₁₀ ) as a phosphorus-containing compound in 40 parts by mass of water was added to 100 parts by mass of coal ash A to obtain a mixture. The mixture was heat treated in a baking furnace at 900 ° C. for 1 hour. A test solution was obtained for the obtained powdery heat-treated product by the above method, and the concentration of harmful trace elements in the test solution was measured by the above method. However, 3.85 mmol / L slaked lime aqueous solution (pH = 11.9) was used as a solvent mixed with a heat-treated product for preparation of a test solution. The analysis results of the obtained heat-treated product are shown in Table 12.

Comparative Example 37
A test solution was obtained by the above method for coal ash A itself used in Example F-32, and the concentration of each harmful trace element in the test solution was measured by the above method. However, 5.0 mmol / L hydrochloric acid aqueous solution (pH 2.3) was used as a solvent to be mixed with the coal ash A for preparation of a test solution. The analysis results are shown in Table 12.

Comparative Example 38
A test solution was obtained for coal ash A itself used in Example F-32 by the above method, and the concentration of each harmful trace element was measured for the test solution by the above method. However, 3.85 mmol / L slaked lime aqueous solution (pH = 11.9) was used as a solvent mixed with the coal ash A for test solution preparation. The analysis results are shown in Table 12.

Examples F-34 and F-35
A mixture was obtained by adding 8 parts by mass or 16 parts by mass of phosphoric acid (H ₃ PO ₄ ) as a phosphorus-containing compound to 100 parts by mass of refuse incineration ash. The mixture was heat treated at 700 ° C. for 1 hour in a baking furnace. A test solution was obtained from the obtained powdery heat-treated product by the above method, and the concentration of harmful trace elements in the test solution was measured by the above method. The analysis results of the obtained heat-treated product are shown in Table 13.

As described above, it is understood that the treatment method of the present invention can be applied without being influenced by the physical properties or composition of incineration ash, and can reduce the elution amount of harmful trace elements from the incineration ash.

According to the treatment method of the present invention, elution of harmful trace elements from incineration ash containing various harmful trace elements is highly productive, economical, efficient, and industrial without using various agents. It can be simply suppressed. In addition, according to the treatment method of the present invention, the elution amount of harmful trace elements can be reduced even under acidic conditions assuming acid rain or under basic conditions due to the presence of a basic compound liberated from the concrete structure. It is possible to effectively reduce the influence of the internal and external pH environment. The treatment method of the present invention is applicable to incineration ash of various physical properties and compositions such as coal ash and waste incineration ash. For this reason, the treatment method of this embodiment is environmental pollution such as reutilization of incinerated ash in construction projects and civil engineering projects, landfill use of waste treated ash that has been dumped in waste disposal sites, soil improvers, etc. It contributes to the effective use of incineration ash in consideration of prevention.

Claims

A method of treating solid waste, comprising the step of mixing incineration ash and a phosphorus source and heating the mixture at 600 ° C. or more and 1200 ° C. or less.
The method for treating solid waste according to claim 1, wherein phosphorus-containing waste is used as the phosphorus source.
The method of treating solid waste according to claim 1, wherein a phosphorus-containing compound is used as the phosphorus source.
The amount of phosphorus in the mixture of the incineration ash and the phosphorus source is 10 times by mass or more relative to the total amount of arsenic, chromium and boron in the incineration ash. The solid waste disposal method as described in a paragraph.
The amount of calcium in the mixture of the incineration ash and the phosphorus source is 30 mass times or more with respect to the total amount of arsenic, chromium and boron in the incineration ash. The solid waste disposal method as described in a paragraph.
The solid waste according to claim 5, wherein the amount of calcium in the mixture of the incineration ash and the phosphorus source is at least 75 times by mass relative to the total amount of arsenic, chromium and boron in the incineration ash. How to handle
The method according to claim 1, wherein the phosphorus-containing waste is at least one selected from the group consisting of sewage sludge-based phosphorus-containing waste, agricultural and fishery-based phosphorus-containing waste, industrial phosphorus-containing waste, and food-based phosphorus-containing waste. The method for treating solid waste according to 2.
The method for treating solid waste according to claim 2 or 7, wherein the phosphorus-containing waste comprises meat and bone meal.
The method for treating solid waste according to claim 2, 7 or 8, wherein general sewage sludge or a combination of industrial sewage sludge and meat-and-bone meal is used as the phosphorus-containing waste.
The amount of calcium in the mixture of the incineration ash and the phosphorus source is 1000 mass times or less with respect to the total amount of arsenic, chromium and boron in the incineration ash. The solid waste disposal method as described in a paragraph.
The solid waste according to claim 10, wherein the amount of calcium in the mixture of the incineration ash and the phosphorus source is 450 mass times or less with respect to the total amount of arsenic, chromium and boron in the incineration ash. How to handle
12. The method according to claim 1, wherein the incineration ash is coal ash and the temperature of heat treatment is 750 ° C. or more, or the incineration ash is waste incineration ash and the temperature of heat treatment is 780 ° C. or less. The solid waste disposal method described in.
The method of treating solid waste according to any one of claims 1 to 12, wherein the amount of phosphorus in the mixture of the incineration ash and the phosphorus source is 0.1% by mass or more and 10% by mass or less.
The method of treating solid waste according to any one of claims 1 to 13, wherein the amount of calcium in the mixture of the incineration ash and the phosphorus source is 0.1% by mass or more and 50% by mass or less.
The phosphorus concentration in the phosphorus source is 5% by mass or more and 60% by mass or less in a value in terms of P 2 O 5 in fluorescent X-ray analysis measured in a state of being calcined at 900 ° C. for 3 hours. The solid waste disposal method as described in 14.
The solid waste according to any one of claims 1 to 15, wherein the amount of the phosphorus source used is 0.1 parts by mass or more and 60 parts by mass or less in terms of phosphorus element with respect to 100 parts by mass of incinerated ash. How to handle
The method of treating solid waste according to any one of claims 1 to 16, wherein the mixture of incineration ash and phosphorus source is heated at 80 ° C to 300 ° C and then heated to 600 ° C to 1200 ° C. .
The solid waste disposal method according to any one of claims 1 to 17, wherein the incineration ash is coal ash generated by burning coal alone or a mixture of coal and biomass.
The solid waste treatment according to any one of claims 1 to 18, wherein paper sludge ash is added to the incineration ash in addition to the phosphorus source and then heated at 600 ° C to 1200 ° C. Method.
The solid waste disposal method according to any one of claims 1 to 19, wherein the incineration ash is heated at 600 ° C or more and 1200 ° C or less after adding a sodium component in addition to the phosphorus source. .
The solid waste disposal method according to claim 20, wherein the sodium component is at least one selected from sodium phosphate, sodium hydroxide and sodium chloride.
22. The method of treating solid waste according to claim 21, wherein the sodium component is sodium chloride.
The method according to any one of claims 19 to 22, wherein the incineration ash is waste incineration ash, and the phosphorus source is a method for reducing the elution of boron, arsenic and hexavalent chromium in waste incineration ash containing sewage sludge-based phosphorus-containing waste. The method for treating solid waste according to item 1 or 2.
The phosphorus-containing compound is at least one selected from the group consisting of condensed phosphoric acid, phosphoric acid, phosphorous acid, hypophosphorous acid, phosphonic acid and phosphinic acid, and salts thereof and hydrates thereof. The solid waste disposal method according to Item 3.
The solid waste according to claim 3 or 24, wherein the phosphorus-containing compound is at least one selected from the group consisting of pentapotassium triphosphate, condensed phosphoric acid, condensed phosphate and hypophosphite. Processing method.
The method according to any one of claims 1 to 25, wherein the elution amount of at least one member selected from the group consisting of boron, arsenic, selenium, fluorine, hexavalent chromium, lead, mercury and cadmium contained in the incineration ash or phosphorus source is reduced. Solid waste disposal method described.
The method for treating solid waste according to claim 26, wherein the elution amount of at least one member of the group consisting of boron, arsenic and hexavalent chromium contained in the incineration ash or phosphorus source is reduced.
Consists of boron, arsenic, selenium, fluorine, hexavalent chromium, lead, mercury and cadmium contained in incineration ash or phosphorus source, which has a step of mixing incineration ash and phosphorus source and heating at 600 ° C. to 1200 ° C. At least one elution suppression method of the group.
The elution inhibiting method according to claim 28, wherein the elution inhibiting of at least one selected from the group consisting of boron, arsenic and hexavalent chromium is inhibited.