JP3737459B2 - Waste recycling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention collects useful materials such as cement raw materials from various difficult-to-process wastes including chlorine, alkali metals, heavy metals, dioxins, etc. such as waste plastic, waste glass, shredder dust, contaminated soil, fly ash, etc. The present invention relates to a waste recycling method.
[0002]
[Prior art]
Conventionally, calcium, heavy metals, chlorides, etc. are separated and recovered from incineration fly ash obtained by incineration of flammable waste (for example, combustible garbage from homes, etc.) or fly ash such as molten fly ash. Various technologies for recycling have been proposed.
For example, Japanese Patent Application Laid-Open No. 2000-212654 discloses that a substance (for example, fly ash) containing a heavy metal component such as zinc and chlorine is added with a mineral acid to be slurried, and the pH is adjusted to 5 or less to dissolve chlorine. A chlorine dissolving step to be performed, and an alkali agent is added to the slurry of the chlorine dissolving step to adjust the pH to 12 or more, and then the heavy metal containing starch is separated and recovered from the chlorine containing filtrate by solid-liquid separation. A method for recovering heavy metals from a material containing heavy metals and chlorine, characterized in that it comprises a starch recovery step is described.
[0003]
Japanese Patent Laid-Open No. 2001-17939 includes washing a cement kiln exhaust gas dust with water, adjusting the obtained wash water to pH 7 to 10, and then adding a sulfurizing agent to recover heavy metals such as lead. In the first stage, the hydrochloric acid is added to the dehydrated cake after the water washing treatment in the first stage and dissolved and leached. A method for treating cement kiln exhaust gas dust comprising a second stage including recovery is described. Further, the publication describes that, in the first stage, the liquid component after removing heavy metals is heated and concentrated, and then cooled to precipitate potassium chloride for recovery. Furthermore, this publication describes that sulfuric acid is added to the liquid component after the heavy metal is recovered in the second stage, and the calcium content is recovered as gypsum (calcium sulfate).
[0004]
[Problems to be solved by the invention]
As described above, various techniques for separating and recovering calcium that can be used as a cement raw material, heavy metal that can be used as a non-ferrous refining raw material, and the like from fly ash containing heavy metal and chlorine are proposed.
However, waste that is difficult to incinerate, such as waste plastic and waste glass, is currently being disposed of in landfills, etc., except for some recyclable resins such as PET resin. is there.
[0005]
On the other hand, recycling of waste containing soluble salts such as incineration fly ash obtained by incineration of combustible waste and recycling of waste that is difficult to incinerate such as waste plastic and waste glass It would be advantageous if they could be integrated to simplify and increase the efficiency of processing steps and reduce the cost of processing.
In view of such a current situation, the present invention is a waste recycling process including waste plastics and waste glass that is difficult to incinerate, and waste containing soluble salts such as incinerated fly ash and molten fly ash. Integrated waste recycling process that can simplify and improve the efficiency of various waste disposal processes, and reduce the costs required for disposal. It aims to provide a method.
[0006]
[Means for Solving the Problems]
As a result of diligent investigations to solve the above problems, the present inventors have found that the residue after washing waste containing pulverized waste such as plastic waste and soluble salts such as fly ash with water. A certain solid content is mixed so that it is likely to volatilize when heated, and this mixture is heat-treated in the kiln, and the calcined residue containing calcium content is used as a cement raw material, etc. In addition to the waste containing the soluble salts, by adopting a treatment method such as washing with the waste containing the soluble salts, waste that is difficult to incinerate and waste containing the soluble salts The present invention has been completed by conceiving that an efficient and low-cost waste recycling method targeted can be realized.
[0007]
That is, in the waste recycling method of the present invention (Claim 1), (A) waste that is difficult to be incinerated (for example, waste plastic, waste glass, shredder dust, etc.) is pulverized and appropriately treated. A waste pretreatment step for obtaining a pulverized product pulverized to a size, and (B) a waste product containing soluble salts such as fly ash is washed with water, and then solid-liquid separated by filtration or the like to obtain a solid content (one calcium content). Water-soluble waste-containing waste water washing step for obtaining a liquid component (which includes chloride ions, sodium ions, potassium ions, etc. in addition to the remainder of calcium and the balance of heavy metals) And (C) mixing the pulverized material obtained in the waste pretreatment step (A) and the solid content obtained in the soluble salt-containing waste water washing step (B) to obtain a mixture, The mixture volatilizes when heated. The amount of chlorine and alkali metal contained in the mixture is adjusted, the mixture is heated in a kiln such as a rotary kiln for producing cement clinker, and kiln exhaust gas dust (specifically, heavy metal or alkali metal A heat treatment step for obtaining a calcined residue (cement raw material) containing calcium and other components (silicon, aluminum, etc.), and (D) the heat treatment step (C). A dust returning step of adding the obtained kiln exhaust gas dust to the waste containing the soluble salts before washing in the soluble salt-containing waste water washing step (B), and (E) the soluble salt-containing waste water washing step (B ) To separate and recover heavy metals (non-ferrous smelting raw materials), calcium (cement raw materials) and chlorides (chemical fertilizer raw materials) from the liquid obtained in Characterized in that it comprises a recovery step.
[0008]
According to the waste recycling method comprising such steps (A) to (E), waste recycling that is difficult to incinerate, such as waste plastic, and soluble salts such as fly ash are included. By integrating waste recycling, heavy metals, calcium and chloride can be recovered efficiently. Moreover, according to the method of the present invention, the solid content obtained by removing the chlorine content obtained by washing the waste containing soluble salts with the soluble salt-containing waste water washing step (B) is difficult to incinerate. Since it is put into the kiln together with the pulverized product, the content of chlorine in the heated object (mixture) in the kiln can be reduced, and as a result, the operation is hindered by the excessive amount of chlorine. Is not generated, and chlorination and volatilization in the kiln can be performed stably and smoothly.
[0009]
In the waste recycling method of the present invention (Claim 2), instead of the dust return step (D), (F) the kiln exhaust gas dust obtained in the heat treatment step (C) and an acid are used. The aqueous solution containing the mixture is mixed and then separated into solid and liquid to obtain a solid and a liquid. The solid is then heated together with the solid obtained in the soluble salt-containing waste water washing step (B). An acid treatment step including sending to the treatment step (C) and sending the liquid component to the fraction recovery step (E) together with the liquid component obtained in the soluble salt-containing waste water washing step (B). And
According to the waste recycling method comprising such steps (A) to (C), (F) and (E), the waste recycling method described above (steps (A) to ( E), in addition to the advantage of the acid treatment step (F) for performing the acid treatment of the kiln exhaust gas dust, the pH of the heavy metal contained in the volatile component of the kiln (kiln exhaust gas dust) is alkaline. Copper and zinc, which are difficult to elute if they were in the region, can be eluted in an acid-adjusted liquid, and heavy metals such as copper, zinc, and lead can be efficiently recovered in the separate recovery step (E). it can.
The amount of chlorine and alkali metal can be adjusted, for example, by adjusting the amount of waste containing chlorine and waste containing alkali metal in the mixture (claim 3).
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of the method of the present invention will be described with reference to the drawings. FIG. 1 shows a waste recycling method (having a dust return step (D) in which a volatile component of a kiln is added to waste containing salt, such as fly ash; hereinafter referred to as “first processing method”) FIG. 2 shows a waste recycling method (having an acid treatment step for acid treatment of kiln exhaust gas dust; hereinafter, also referred to as “second treatment method”). It is a flowchart which shows an example.
[0011]
As shown in FIG. 1, the first treatment method of the present invention comprises (A) a waste pretreatment step of pulverizing waste that is difficult to incinerate to obtain a pulverized product pulverized to an appropriate size. (B) Waste containing soluble salts (also referred to as soluble salt-containing waste in the present specification) is washed with water and then separated into solid and liquid to obtain solids and liquids. Mixing the pulverized material obtained in the step (C) waste pretreatment step (A) and the solid content obtained in the soluble salt-containing waste water washing step (B) to obtain a mixture, Heating the mixture in a kiln to adjust the amounts of chlorine and alkali metals so that the mixture is likely to volatilize and chlorinate when heated to obtain kiln exhaust gas dust and a calcination residue containing calcium. Processing step and kill obtained in (D) heat treatment step (C) From the liquid obtained in the dust return step of adding the exhaust gas dust to the soluble salt-containing waste before washing in the soluble salt-containing waste water washing step (B), and (E) the soluble salt-containing waste water washing step (B), It consists of a separate collection step of separating and recovering heavy metals, calcium and chlorides.
[0012]
Hereinafter, each process will be described.
[A. Waste pretreatment process]
This is a step of pulverizing waste that is difficult to incinerate to obtain a pulverized product pulverized to an appropriate size.
Specific examples of wastes that are difficult to incinerate include, for example, waste plastics (specifically, molded products made of polypropylene resin, polyethylene resin, hard or soft vinyl chloride resin, etc.), waste glass, ceramics, various Shredder dust (specifically, shredder dust obtained by crushing scrap vehicles, shredder dust obtained by crushing waste home appliances, etc.), construction mixed waste (gypsum board generated when building is demolished, etc.) ), Synthetic resin-coated electric wires, contaminated soil (for example, soil contaminated with heavy metals or dioxins), and the like.
[0013]
Examples of elements contained in wastes that are difficult to incinerate include calcium, silicon, aluminum, chlorine, sodium, potassium, copper, lead, zinc, and the like.
The content of these elements varies depending on the type of waste that is difficult to incinerate. For example, when the ratio of chlorine-containing resins such as vinyl chloride resin and polyvinylidene chloride resin in waste that is difficult to incinerate is large, the chlorine content in the waste increases. Moreover, when the ratio of the waste glass in the waste which is difficult to incinerate is large, the content rate of silicon, sodium, or the like in the waste becomes large. When the ratio of shredder dust in waste that is difficult to incinerate is large, the content of metal (for example, aluminum) in the waste increases.
The average particle size of the pulverized waste that is difficult to be incinerated is only required to be large enough to be baked in the kiln and varies depending on the type of material, but is preferably 50 mm or less, more preferably 6 mm. It is as follows.
Examples of the pulverizing means include a pot mill, a vibration mill, a roller mill, a ball mill, a collision type jet pulverizer, and a turbo pulverizer.
When the size of the pulverized product is relatively large, the firing residue after the heat treatment in the kiln may be obtained as a granular material. This granular material is free from heavy metals and chlorine, and can be recycled as an aggregate.
[0014]
[B. Soluble salt-containing waste water washing process]
This is a process in which a soluble salt-containing waste such as fly ash is washed with water and then solid-liquid separated by filtration or the like to obtain a solid content and a liquid content.
Here, the term "fly ash" is extracted from incineration fly ash discharged from incineration facilities such as garbage and sewage sludge, molten fly ash discharged from melting facilities such as incineration ash, and cement manufacturing processes. Used to include chlorine bypass dust and bag filter dust in ecocement manufacturing.
Fly ash contains elements, such as calcium, silicon, aluminum, chlorine, sodium, potassium, copper, lead, zinc, for example.
The composition ratio of various elements contained in fly ash varies depending on the type of fly ash. For example, the average composition of molten fly ash is 30% calcium, 9% sodium, 10% potassium, 1.6% lead, 5.4% zinc, 24% chlorine (but chlorine) The weight ratio in terms of oxide is indicated.
[0015]
In this step, for example, soluble salt-containing waste such as fly ash and water are stirred so that the solid-liquid ratio (mass of soluble salt-containing waste in 1 liter of slurry) is preferably 100 to 600 g / liter. After mixing to make a slurry, the slurry is filtered to obtain a solid and a liquid. When the solid-liquid ratio is less than 100 g / liter, not only the volume of the mixing tank is increased, but also the time required for solid-liquid separation is increased, and the processing efficiency is lowered. When the solid-liquid ratio exceeds 600 g / liter, it is difficult to sufficiently elute various water-soluble components contained in the solid content in the liquid, which is not preferable.
[0016]
The pH of the slurry comprising soluble salt-containing waste such as fly ash and water is, for example, about 11 to 12. Since the elution rate of copper and zinc is small near this numerical range, it is preferable to add an acid such as hydrochloric acid as necessary to lower the pH of the slurry and increase the elution rate of copper and zinc. .
The time for stirring the soluble salt-containing waste and water varies depending on the amount of slurry and the solid-liquid ratio, but is, for example, about 10 to 40 minutes.
In addition, when the calcium ion concentration in a liquid is high, the elution rate of lead will become high. From this viewpoint, the calcium ion concentration is preferably 45 g / liter or more. In the present invention, a water-soluble calcium salt such as calcium chloride can be added as necessary to increase the elution rate of lead.
The stirred slurry is subjected to solid-liquid separation by filtration or the like. Examples of the solid-liquid separation means include a belt filter and a filter press.
The solid content after the solid-liquid separation includes, for example, calcium, silicon, aluminum, copper, zinc, lead and the like. The liquid component contains, for example, sodium, potassium, chlorine (chloride ion), calcium, copper, zinc, lead and the like.
[0017]
[C. Heat treatment process]
The pulverized material obtained in the waste pretreatment step (A) and the solid content obtained in the soluble salt-containing waste water washing step (B) are mixed to obtain a mixture, and the mixture is volatile by evaporation during heating. In this step, the amount of chlorine and alkali metal contained in the mixture is adjusted so that the mixture is easily heated, and the mixture is heated in the kiln to obtain kiln exhaust gas dust and a calcined residue containing calcium.
In this step (C), heavy metals in the solid content obtained in the soluble salt-containing waste water washing step (B) (that is, those contained in the vitreous particles or insoluble double salts are formed. The soluble salt-containing waste water washing step (B) does not elute in the liquid, but remains in the solid content) and decomposes and volatilizes by high-temperature treatment in the kiln and elutes in the liquid. It changes to a form (chloride) that is easy to do. Therefore, these heavy metals can be eluted in the liquid at a high elution rate by a subsequent water washing treatment (that is, a water washing treatment after the dust returning step (D)).
On the other hand, if the pulverized product obtained in the waste pretreatment step (A) has a high chlorine content, the kiln must be added unless solids derived from waste (for example, fly ash) containing soluble salts are added. When heat-treating the inside, it is necessary to add natural raw materials such as lime and clay in order to prevent the pulverized material from melting and stabilize the operation of the kiln. In this respect, in this step (C), since solids derived from waste containing soluble salts (made of calcium etc. from which chlorine content has been removed) are added, it is obtained in the waste grinding step (A). Even when the chlorine content in the pulverized product is high, it is not necessary to add lime, clay, or the like from outside the system, and the treatment can be performed efficiently.
[0018]
The mixing of the pulverized material obtained in the waste pretreatment step (A) and the solid content obtained in the soluble salt-containing waste water washing step (B) is not only to add them together, but also to a uniform state. It is desirable to stir so that The reason is as follows.
The pulverized waste obtained in the waste pretreatment step (A), which is difficult to be incinerated, may contain chlorine at a relatively high content by containing a chlorine-containing resin or the like. On the other hand, the solid content after the water washing treatment of the waste obtained in the soluble salt-containing waste water washing step (B) has a small chlorine content because the soluble chlorine content is eluted in the liquid. If the pulverized material in the waste pretreatment step (A) and the solid content in the soluble salt-containing waste water washing step (B) are put into the kiln without sufficiently stirring and mixing, they are heated in the kiln. As the chlorine content in the processed material (mixture) varies greatly, the chlorination volatilization phenomenon (a phenomenon in which heavy metals volatilize with the chlorine content) does not occur stably in the kiln, and the processing efficiency may decrease. is there. In particular, when an object to be processed with a relatively high chlorine content (for example, an object to be processed mainly composed of a pulverized product of chlorine-containing resin) is heated in a kiln, the object to be treated before the chlorination phenomenon occurs. Melting of the processed material occurs, and as a result, not only the chlorination volatilization phenomenon is inhibited, but also the kiln operation may be hindered. Therefore, the pulverized material obtained in the waste pretreatment step (A) and the solid content obtained in the soluble salt-containing waste water washing step (B) are thoroughly stirred and mixed, and the chlorine content concentration in the mixture is determined. It is desirable to make it uniform.
[0019]
Although the compounding ratio of the pulverized material obtained in the step (A) and the solid content obtained in the step (B) is not particularly limited, for example, the mass ratio is 10: 1 to 1:10.
The amount of chlorine and alkali metals contained in the mixture is adjusted so that the mixture of the pulverized product obtained in step (A) and the solid content obtained in step (B) is easily volatile in the kiln. After that, it is thrown into the kiln.
In order to adjust the amount of chlorine and alkali metal in the mixture as described above, for example, waste (for example, vinyl chloride resin) containing chlorine in the mixture put into the kiln and waste containing alkali metal What is necessary is just to adjust the quantity (for example, waste glass etc.) suitably. In addition, there is no problem even if a waste containing chlorine or a waste containing alkali metal is additionally charged into the kiln.
Specific examples of the kiln as the heating means include a rotary kiln for producing cement clinker. In this way, the cost required for implementing the present invention can be reduced by using existing equipment.
The heating temperature in the kiln is preferably 1,000 to 1,500 ° C, more preferably 1,100 to 1,400 ° C. When the temperature is less than 1,000 ° C., the chlorination volatilization phenomenon does not occur sufficiently, heavy metals, alkali metals and chlorine do not volatilize sufficiently, and when the temperature exceeds 1,500 ° C., the amount of energy becomes excessive, Cost increases.
[0020]
Kiln exhaust gas dust contains alkali metals such as sodium and potassium, heavy metals such as copper, zinc and lead, and chlorine. As will be described later, the kiln exhaust gas dust is added to the soluble salt-containing waste (for example, fly ash) before washing in the soluble salt-containing waste water washing step (B) by the dust returning step (D).
On the other hand, the solid that remains as a baking residue in the kiln without volatilizing contains calcium, silicon, aluminum, etc., and since harmful heavy metals and chlorine are removed, it can be used as a cement raw material, aggregate, etc. It can be recycled.
[0021]
[D. Dust return process]
In this step, the kiln exhaust gas dust obtained in the heat treatment step (C) is added to the soluble salt-containing waste (for example, fly ash) before washing in the soluble salt-containing waste water washing step (B).
In the present invention, by adding the kiln exhaust gas dust to the waste containing soluble salts before washing with water, chlorine, sodium, potassium, heavy metals (for example, copper, zinc, lead) derived from waste that is difficult to incinerate Can be eluted together with chlorine, sodium, potassium, heavy metals (eg, copper, zinc, lead), etc. in waste containing soluble salts, and efficient treatment can be realized at low cost. Can do.
[0022]
[E. Separation and collection process]
This is a step of separating and recovering heavy metal, calcium and chloride from the liquid (filtrate) obtained in the soluble salt-containing waste water washing step (B).
For example, as shown in FIG. 1, this step includes a series of processing operations arranged in the order of heavy metal recovery processing, calcium recovery processing, and chloride recovery processing.
The heavy metal recovery process is performed, for example, by adding a sulfiding agent to the liquid after washing the soluble salt-containing waste, followed by solid-liquid separation by filtration or the like. Specific examples of the sulfiding agent include sodium hydrosulfide (NaHS) and sodium sulfide (Na ₂ S) and the like. By adding a sulfiding agent, lead sulfide (PbS), zinc sulfide (ZnS), copper sulfide (CuS) and the like can be obtained as precipitates.
[0023]
The pH of the filtrate when adding the sulfiding agent is adjusted to 6.5 to 8.0, preferably 6.8 to 7.7. If the pH is less than 6.5, the sulfurization reaction of zinc in the liquid becomes insufficient, the amount of zinc sulfide produced decreases, and the zinc recovery rate decreases. When the pH exceeds 8.0, the amount of calcium remaining as solid (hydroxide) without being eluted in the liquid increases, and separation of heavy metal and calcium becomes insufficient. In addition, since heavy metals are present in the solids as hydroxides instead of sulfides, this heavy metal hydroxide takes in chloride ions, sodium ions, potassium ions, etc. eluted in the liquid, The content of components other than heavy metals (chloride ions, sodium ions, etc.) in the solid content increases, and the value of the solid content as a nonferrous refining raw material decreases.
The pH may be adjusted using an acid such as hydrochloric acid or an alkalizing agent such as sodium hydroxide.
[0024]
In the calcium recovery treatment, for example, an alkaline agent such as sodium hydroxide is added to the filtrate after removing heavy metals, and the pH is adjusted to preferably 12.5 or more, more preferably 13.0 or more, and calcium hydroxide is obtained. After the precipitate is formed, the solid-liquid separation is performed by filtration or the like.
[0025]
The chloride recovery process is performed, for example, by a crystallization method. That is, first, the filtrate after the above calcium recovery treatment is concentrated to a concentration suitable for chloride precipitation by membrane treatment or evaporation. The filtrate is then heated under reduced pressure to evaporate the liquid. At this time, if the temperature of the filtrate is changed, various chlorides can be separated and precipitated based on the difference in the crystal precipitation temperature. For example, to separate and recover sodium chloride and potassium chloride, first, the temperature of the filtrate is raised to 50 ° C. or higher to precipitate sodium chloride, which is filtered and collected, and then the temperature of the filtrate is 30 ° C. or lower. The solution may be cooled to precipitate potassium chloride, which may be collected by filtration.
Distilled water obtained by evaporation by the crystallization method can be used as washing water for waste containing soluble salts in the soluble salt-containing waste water washing step (B).
[0026]
As shown in FIG. 2, the second treatment method of the present invention is a method in which the dust return step (D) is replaced with an acid treatment step (F) in the first treatment method of the present invention. (A) A waste pretreatment step for pulverizing waste that is difficult to be incinerated to obtain a pulverized product that has been pulverized to an appropriate size; (B) After washing the waste containing soluble salts with water, Soluble salt-containing waste water washing step for separating and obtaining solids and liquids, (C) pulverized product obtained in waste pretreatment step (A), and soluble salt-containing waste water washing step (B) The resulting solid is mixed to obtain a mixture, and the mixture is heated in a kiln by adjusting the amounts of chlorine and alkali metals contained in the mixture so that the mixture easily volatilizes when heated. Heat treatment to obtain kiln exhaust gas dust and calcined residue containing calcium And (F) the kiln exhaust gas dust obtained in the heat treatment step (C) and an aqueous solution containing an acid, and then solid-liquid separation to obtain a solid and a liquid, The solid content is sent to the heat treatment step (C) together with the solid content of the soluble salt-containing waste water washing step (B), and the liquid fraction is separated together with the liquid content of the soluble salt-containing waste water washing step (B). Acid treatment step sent to the recovery step (E), and (E) a separate recovery step for separating and recovering heavy metals, calcium and chloride from the liquid obtained in the soluble salt-containing waste water washing step (B) It consists of
Among these steps, steps (A) to (C) and (E) are the same as those in the first treatment method of the present invention, and thus the description thereof is omitted. Hereinafter, the acid treatment step (F) will be described.
[0027]
[F. Acid treatment process]
In this step, first, the kiln exhaust gas dust obtained in the heat treatment step (C) and an aqueous solution containing an acid are mixed to prepare a slurry.
In this invention, heavy metals, such as copper and zinc, can be eluted in a liquid by mixing kiln exhaust gas dust and the aqueous solution containing an acid. In addition, since the heavy metal in kiln exhaust gas dust is a volatile component in a kiln and exists in the form of a chloride as mentioned above, it is easy to elute in water.
Here, as a specific example of the acid for eluting heavy metals, for example, hydrochloric acid and the like can be mentioned.
By adding an acid, the pH of the slurry is preferably adjusted to 1.5-4.0, more preferably 2.0-3.0. By adjusting the pH to 4.0 or less, heavy metals such as copper and zinc can be eluted in the liquid at a high elution rate. Further, by adjusting the pH to 1.5 or more, it is possible to avoid an increase in cost due to the use of an excessive amount of acid.
[0028]
Next, the slurry is solid-liquid separated by filtration or the like to obtain a solid content and a liquid content.
Among these, solid content is sent to a heat treatment process (C) with the solid content obtained by solid-liquid separation in the soluble salt containing waste water washing process (B).
On the other hand, the liquid is sent to the separation and recovery step (E) together with the liquid obtained by solid-liquid separation in the soluble salt-containing waste water washing step (B).
The treatment method after the heat treatment step (C) and the treatment method after the fraction collection step (E) are the same as those in the first treatment method described above.
The distilled water obtained during the chloride recovery process (crystallization method) in the fractional recovery step (E) is the wash water for the soluble salt-containing waste (for example, fly ash) in the soluble salt-containing waste water washing step (B). In addition, it can be used as water for slurrying kiln exhaust gas dust (water for dissolving acid) in the acid treatment step (F).
[0029]
【The invention's effect】
According to the waste recycling method of the present invention, the amount of chemicals used is suppressed for waste that is difficult to incinerate, such as plastic waste, and waste that contains soluble salts such as fly ash. It is possible to efficiently process at low cost by separating and collecting heavy metals that can be used as non-ferrous refining raw materials, calcium that can be used as cement raw materials, sodium chloride used as industrial raw materials, etc. it can.
[Brief description of the drawings]
FIG. 1 is a flowchart showing an example of a waste recycling method according to the present invention.
FIG. 2 is a flowchart showing another example of the waste recycling method of the present invention.

Claims (3)

(A) A waste pretreatment step of pulverizing waste that is difficult to incinerate to obtain a pulverized product pulverized to an appropriate size;
(B) After washing the waste containing soluble salts with water, the solid-liquid separation, and the soluble salt-containing waste water washing step for obtaining solids and liquids;
(C) The pulverized material obtained in the waste pretreatment step (A) and the solid content obtained in the soluble salt-containing waste water washing step (B) are mixed to obtain a mixture, and the mixture The amount of chlorine and alkali metal contained in the mixture is adjusted so that the salt easily evaporates when heated, and the mixture is heated in the kiln to obtain kiln exhaust gas dust and a calcination residue containing calcium. Process,
(D) A dust return step of adding the kiln exhaust gas dust obtained in the heat treatment step (C) to the waste containing the soluble salts before washing in the soluble salt-containing waste water washing step (B),
(E) A waste collection process comprising a separation and recovery step of separating and recovering heavy metals, calcium and chloride from the liquid obtained in the soluble salt-containing waste water washing step (B). Recycling method. Instead of the dust return step (D),
(F) The kiln exhaust gas dust obtained in the heat treatment step (C) is mixed with an aqueous solution containing an acid, and then solid-liquid separation is performed to obtain a solid content and a liquid content. The solid content obtained in the soluble salt-containing waste water washing step (B) is sent to the heat treatment step (C), and the liquid content is obtained in the soluble salt-containing waste water washing step (B). The waste recycling process method of Claim 1 including the acid treatment process sent to the said fraction collection process (E) with the liquid part. The amount of chlorine and alkali metal is adjusted by adjusting the amount of waste containing chlorine and waste containing alkali metal in the mixture charged into the kiln. Waste recycling method.

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