A method for treating fly ash from solid waste incineration

Abstract

The present invention relates to the technical field of solid waste incineration fly ash, and in particular to a method for treating solid waste incineration fly ash. The method determines whether it is necessary to increase the operation of adding a first soluble salt to ensure that the proportion of soluble salts in the solution after the target solvent and the solid waste incineration fly ash to be treated is between 10% and 20%, and this proportion can be beneficial to improving the removal efficiency of carbon from the solid waste incineration fly ash by the target solvent under the premise of ensuring a high removal efficiency of the soluble salt. In addition, the removal efficiency of harmful organic matter from the solid waste incineration fly ash is improved by using isopropanol and ethanol dissolved in water in the target solvent, the calcium content in the washed ash is increased by using the target carbonate in the target solvent, and the water in the target solvent is used to ensure the removal efficiency of soluble salts from the solid waste incineration fly ash. The above scheme can improve the removal efficiency of soluble salts, carbon and harmful organic matter in the solid waste incineration fly ash.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste incineration fly ash, and in particular to a method for treating solid waste incineration fly ash. Background Art

[0002] In order to reduce the volume and quantity of solid waste (referred to as solid waste) such as urban domestic garbage and some hazardous waste, solid waste incineration technology has been widely used, but a large amount of toxic solid waste incineration fly ash will be produced during the solid waste incineration process. Solid waste incineration fly ash, as a hazardous solid waste containing a large amount of soluble salts and harmful organic matter, needs to be effectively treated and disposed of.

[0003] In the related art, solid waste incineration fly ash is usually treated by water washing, that is, using water to remove soluble salts and harmful organic matter in solid waste incineration fly ash, but this method has a low removal efficiency. In addition, solid waste incineration fly ash also has a high carbon content, and a simple water washing treatment method is difficult to effectively remove carbon from solid waste incineration fly ash.

[0004] Therefore, there is an urgent need for a method for treating solid waste incineration fly ash to solve the above problems. Summary of the invention

[0005] The embodiment of the present invention describes a method for treating solid waste incineration fly ash, which can improve the removal efficiency of soluble salts, carbon and harmful organic matter in the solid waste incineration fly ash.

[0006] One embodiment of the present invention provides a method for treating fly ash from solid waste incineration, comprising:

[0007] Determine the actual proportion of soluble salts in the solid waste incineration fly ash to be treated;

[0008] When the actual ratio is greater than the preset ratio, the following steps are performed: the target solvent is mixed with the solid waste incineration fly ash to be treated and centrifuged to obtain an organic layer, a carbon black layer, an inorganic layer and an ash layer distributed from top to bottom; the organic layer, the carbon black layer, the inorganic layer and the ash layer are separated respectively to obtain organic components, carbon black, brine and elution ash that can be recycled in turn; wherein the ratio of soluble salts in the solution after the target solvent and the solid waste incineration fly ash to be treated is between 10% and 20%;

[0009] When the actual ratio is not greater than the preset ratio, the following steps are performed: the target solvent, the solid waste incineration fly ash to be treated and the first soluble salt are mixed and centrifuged to obtain a liquid phase layer, a carbon black layer and an ash layer distributed from top to bottom; the liquid phase layer, the carbon black layer and the ash layer are separated respectively to obtain a liquid phase layer to be treated, recyclable carbon black and eluted ash in sequence; a second soluble salt is added to the liquid phase layer to be treated to obtain organic components and brine that can be recycled; wherein the proportion of soluble salts in the solution after the target solvent, the solid waste incineration fly ash to be treated and the first soluble salt are mixed is between 10% and 20%;

[0010] The preset ratio is any value between 40% and 50%, the target solvent includes an organic component and an inorganic component, the organic component includes isopropanol and ethanol, the inorganic component includes a target carbonate and water, and the target carbonate includes sodium carbonate and / or potassium carbonate.

[0011] According to the above embodiment, the proportion of the isopropanol to the organic component is 50% to 90%, and the proportion of the ethanol to the organic component is 10% to 50%.

[0012] According to the above embodiment, the organic component accounts for 20% to 90% of the target solvent, and the inorganic component accounts for 10% to 80% of the target solvent.

[0013] According to the above embodiment, the mass concentration ratio of the target carbonate to water is 1:100 to 1:10.

[0014] According to the above embodiment, the first soluble salt and the second soluble salt both include sodium salt and / or potassium salt.

[0015] According to the above embodiment, after obtaining the recyclable organic components, the method further comprises:

[0016] The recyclable organic component is distilled to obtain the organic component and water used as the target solvent.

[0017] According to the above embodiment, after obtaining the recyclable brine, the method further comprises:

[0018] The recyclable brine is subjected to heating treatment, cooling crystallization and evaporation crystallization in sequence to obtain calcium hydroxide, the target carbonate, chloride salt and water in sequence; wherein the target carbonate and water are used as inorganic components in the target solvent, and the chloride salt is used as the second soluble salt.

[0019] According to the above embodiment, the temperature of the heating treatment is 40-50°C, and the temperature of the cooling crystallization is 20-30°C.

[0020] According to the above embodiment, after obtaining the recyclable organic components, carbon black and brine, the method further comprises:

[0021] The recyclable carbon black is dried, and the dried carbon black is activated by the calcium hydroxide to obtain activated carbon.

[0022] According to the above embodiment, it also includes:

[0023] When the target solvent and the solid waste incineration fly ash to be treated are mixed or when the target solvent, the solid waste incineration fly ash to be treated and the first soluble salt are mixed, the flue gas generated by the solid waste incineration power plant is introduced into the mixed liquid.

[0024] According to the above embodiment, the method of introducing the flue gas generated by the solid waste incineration power plant into the mixed liquid includes:

[0025] Using the activated carbon to adsorb flue gas generated by a solid waste incineration power plant;

[0026] The adsorbed flue gas is introduced into the mixed liquid.

[0027] According to the method for treating solid waste incineration fly ash provided by the embodiment of the present invention, by determining the actual proportion of soluble salts in the solid waste incineration fly ash to be treated, it can be determined whether it is necessary to increase the operation of adding the first soluble salt to ensure that the proportion of soluble salts in the solution after the target solvent and the solid waste incineration fly ash to be treated is between 10% and 20%, and this proportion can be beneficial to improve the removal efficiency of carbon from solid waste incineration fly ash by the target solvent under the premise of ensuring a high removal efficiency of soluble salts. In addition, by using isopropanol and ethanol soluble in water in the target solvent to improve the removal efficiency of harmful organic matter from solid waste incineration fly ash, using the target carbonate in the target solvent to increase the calcium content in the washed ash to reduce the hardness of the brine, the softening cost of the brine can be reduced, and the water in the target solvent is used to ensure the removal efficiency of soluble salts from solid waste incineration fly ash. In summary, the above scheme can improve the removal efficiency of soluble salts, carbon and harmful organic matter in solid waste incineration fly ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic flow chart of a method for treating fly ash from solid waste incineration according to an embodiment is shown;

[0030] Figure 2 A schematic diagram showing a result after solid waste incineration fly ash and a target solvent are mixed and centrifuged according to an embodiment;

[0031] Figure 3 Another schematic diagram of the result after the solid waste incineration fly ash and the target solvent are mixed and centrifuged according to one embodiment is shown;

[0032] Figure 4 for Figure 3 Schematic diagram of the result of adding a second soluble salt to the middle liquid phase. DETAILED DESCRIPTION

[0033] The solution provided by the present invention is described below in conjunction with the accompanying drawings.

[0034] Figure 1 A schematic flow chart of a method for treating solid waste incineration fly ash according to an embodiment is shown.

[0035] like Figure 1 As shown, the method for treating fly ash from solid waste incineration includes:

[0036] Step 101, determining the actual proportion of soluble salts in the solid waste incineration fly ash to be treated;

[0037] Step 102: When the actual ratio is greater than the preset ratio, the following steps are performed: the target solvent is mixed with the solid waste incineration fly ash to be treated and centrifuged to obtain an organic layer, a carbon black layer, an inorganic layer and an ash layer distributed from top to bottom (see Figure 2 ); the organic layer, the carbon black layer, the inorganic layer and the ash layer are separated respectively, and the organic component, carbon black, brine and elution ash which can be recycled are obtained in turn; wherein the proportion of soluble salt in the solution after the target solvent is mixed with the solid waste incineration fly ash to be treated is between 10% and 20%;

[0038] Step 103: When the actual ratio is not greater than the preset ratio, the following steps are performed: the target solvent, the solid waste incineration fly ash to be treated and the first soluble salt are mixed and centrifuged to obtain a liquid phase layer, a carbon black layer and an ash layer distributed from top to bottom (see Figure 3 ); the liquid phase layer, the carbon black layer and the ash layer are separated respectively to obtain the liquid phase layer to be treated, the recyclable carbon black and the eluted ash in turn; the second soluble salt is added to the liquid phase layer to be treated to obtain the organic component and the brine which can be recycled (see Figure 4 ); wherein the ratio of the soluble salt in the solution after the target solvent, the solid waste incineration fly ash to be treated and the first soluble salt is between 10% and 20%;

[0039] The preset ratio is any value between 40% and 50%, the target solvent includes an organic component and an inorganic component, the organic component includes isopropanol and ethanol, the inorganic component includes a target carbonate and water, and the target carbonate includes sodium carbonate and / or potassium carbonate.

[0040] In this embodiment, by determining the actual proportion of soluble salts in the solid waste incineration fly ash to be treated, it can be determined whether it is necessary to increase the operation of adding the first soluble salt to ensure that the proportion of soluble salts in the solution after the target solvent and the solid waste incineration fly ash to be treated is between 10% and 20%, and this proportion can be beneficial to improve the removal efficiency of carbon from the solid waste incineration fly ash by the target solvent while ensuring a high removal efficiency of soluble salts. In addition, by using isopropanol and ethanol soluble in water in the target solvent to improve the removal efficiency of harmful organic matter from the solid waste incineration fly ash, using the target carbonate in the target solvent to increase the calcium content in the washed ash to reduce the hardness of the brine, the softening cost of the brine can be reduced, and the water in the target solvent is used to ensure the removal efficiency of soluble salts from the solid waste incineration fly ash. In summary, the above scheme can improve the removal efficiency of soluble salts, carbon and harmful organic matter in the solid waste incineration fly ash.

[0041] It should be noted that the organic components selected for the above-mentioned target solvent are isopropanol and ethanol soluble in water. The inventors found during the experiment that:

[0042] 1) If the organic component in the target solvent is selected, for example, methanol, no matter how high the soluble salt ratio of the target solvent and the solid waste incineration fly ash to be treated is, methanol has a strong hydrophilicity (although the soluble salt ratio increases, the hydrophilicity of methanol decreases (i.e., the degree of reduction in the hydrophilicity of methanol is the lowest), it is still difficult to remove carbon from the solid waste incineration fly ash and separate it from the inorganic layer), so its centrifugation result is only a liquid layer and an ash layer distributed from top to bottom, that is, there is no carbon black layer (i.e., the purpose of decarbonization cannot be achieved) and the organic layer and the inorganic layer cannot be separated (in addition, even if a second soluble salt is added later, the organic component cannot be recycled);

[0043] 2) If the organic components in the target solvent are selected, for example, isopropanol and ethanol, and the actual proportion of soluble salts in the solid waste incineration fly ash to be treated is greater than the preset proportion, the hydrophilicity of isopropanol and ethanol decreases. At this time, isopropanol and ethanol will show hydrophobicity, and the target solvent contains water. Therefore, the target solvent as a whole shows both hydrophilicity and hydrophobicity. The hydrophilic groups "adhere" to the surface of the carbon inward, and the hydrophobic groups form a hydrophobic film outward, thereby making the carbon floatable, that is, it is removed from the surface of the solid waste incineration fly ash in the form of carbon black; however , it is possible that for ethanol, as the salt content of the system increases, the degree of reduction in its hydrophilicity is moderate (i.e., the hydrophilicity of ethanol may be reduced to a level where carbon black can be separated but cannot be separated from water). Therefore, when the organic components in the target solvent include ethanol in addition to isopropanol, the mutual solubility of the organic components and the inorganic components in the target solvent can be further improved, that is, the overall hydrophilicity and hydrophobicity of the target solvent can be increased, so that more carbon and harmful organic matter can be removed from the solid waste incineration fly ash, that is, the removal efficiency of carbon and harmful organic matter can be further improved;

[0044] If the organic component in the target solvent is selected from isopropanol and ethanol, for example, and the actual proportion of soluble salts in the solid waste incineration fly ash to be treated is not greater than the preset proportion, in order to separate the carbon black, it is necessary to add a first soluble salt to the solution to reduce the hydrophilicity of the organic component and increase the hydrophobicity of the organic component; similarly, the centrifugation results corresponding to isopropanol and ethanol are a liquid phase layer, a carbon black layer and an ash layer distributed from top to bottom; however, by subsequently adding a second soluble salt, the liquid phase layer can be separated, that is, the organic component can be recycled;

[0045] 3) If the organic component in the target solvent is selected to be insoluble in water, such as benzene and / or n-hexane, and the actual proportion of soluble salts in the solid waste incineration fly ash to be treated is greater than the preset proportion, the centrifugation results corresponding to benzene and / or n-hexane are organic layers, carbon black layers, inorganic layers and ash layers distributed from top to bottom; however, when the actual proportion of soluble salts in the solid waste incineration fly ash to be treated is not greater than the preset proportion, even if the first soluble salt is continued to be added to the solution to make its salt content between 10% and 20%, the centrifugation results of the experiment conducted by the inventor are organic layers, inorganic layers and ash layers distributed from top to bottom, that is, no carbon black layer appears, not to mention the recovery and utilization of carbon black at this time.

[0046] In summary, the organic components selected for the target solvent are isopropanol and ethanol that are soluble in water, and cannot be other organic components that are soluble in water or organic components that are insoluble in water. This is a conclusion obtained by comprehensively considering the multiple purposes achieved by the embodiments of the present invention.

[0047] In one embodiment of the present invention, the proportion of isopropanol to the organic component is 50% to 90%, and the proportion of ethanol to the organic component is 10% to 50%.

[0048] From the above analysis, it can be seen that in order to separate more carbon black, it is necessary to ensure that the organic component has a certain hydrophobicity, that is, the content of isopropanol should be higher than that of ethanol, so that the target solvent has a higher hydrophobicity.

[0049] In one embodiment of the present invention, the organic component accounts for 20% to 90% of the target solvent, and the inorganic component accounts for 10% to 80% of the target solvent. In some embodiments, when the organic component and the inorganic component account for 40% to 60% of the target solvent, respectively, it can ensure a good effect of reducing the hardness of the brine and a good effect of removing harmful organic matter, carbon and salt.

[0050] In one embodiment of the present invention, the mass concentration ratio of the target carbonate to water is 1:100 to 1:10.

[0051] In one embodiment of the present invention, the first soluble salt and the second soluble salt both include sodium salt and / or potassium salt.

[0052] In some embodiments, the eluted ash can be landfilled, recycled, etc., which is not specifically limited in this embodiment of the present invention.

[0053] In one embodiment of the present invention, after obtaining the recyclable organic component, the process further comprises:

[0054] The recyclable organic component is distilled to obtain the organic component and water used as the target solvent.

[0055] In one embodiment of the present invention, after obtaining the recyclable brine, the method further comprises:

[0056] The recyclable brine is subjected to heating treatment, cooling crystallization and evaporation crystallization in sequence to obtain calcium hydroxide, target carbonate, chloride salt and water in sequence; wherein the target carbonate and water are used as inorganic components in the target solvent, and the chloride salt is used as the second soluble salt.

[0057] In one embodiment of the present invention, the temperature of the heating treatment is 40-50°C, and the temperature of the cooling crystallization is 20-30°C.

[0058] In this embodiment, the solid waste incineration fly ash to be treated contains a small amount of calcium hydroxide and calcium oxide. After calcium oxide comes into contact with water, it will react to form calcium hydroxide, and calcium hydroxide can be obtained by heating. Considering the separation of calcium hydroxide, for example, filtering can be used. In addition, the purpose of heating the brine is to create temperature conditions for the subsequent separation of target chloride salt and target carbonate. The specific reason is that the solubility of carbonate varies greatly with temperature, so it can be considered to use cooling crystallization (for example, from 40 to 50 ° C to 20 to 30 ° C) to achieve the separation of carbonate; at the same time, heating can evaporate water, which is conducive to evaporation and crystallization to obtain chloride salt.

[0059] In one embodiment of the present invention, after obtaining the recyclable organic components, carbon black and brine, the process further comprises:

[0060] The recyclable carbon black is dried and activated with calcium hydroxide to obtain activated carbon.

[0061] In one embodiment of the present invention, it also includes:

[0062] When the target solvent and the solid waste incineration fly ash to be treated are mixed or when the target solvent, the solid waste incineration fly ash to be treated and the first soluble salt are mixed, the flue gas generated by the solid waste incineration power plant is introduced into the mixed liquid.

[0063] In this embodiment, the flue gas (containing about 10% CO2) generated by the solid waste incineration power plant is introduced into the mixed solution to reduce the pH of the mixed solution to improve the removal efficiency of insoluble chloride salts (among which CaClOH, Ca6(CO3)2(OH)7Cl, 3CaO·Al2O3·CaCl2·10H2O are all common insoluble salts). The specific mechanism is as follows:

[0064] 2CaClOH+CO2→CaCO3+CaCl2+H2O;

[0065] 2Ca6(CO3)2(OH)7Cl+7CO2→11CaCO3+7H2O+CaCl2;

[0066] 3CaO·Al2O3·CaCl2·10H2O+3CO2→3CaCO3+Al2O3·xH2O+CaCl2+(10-x)H2O.

[0067] In one embodiment of the present invention, the flue gas generated by a solid waste incineration power plant is introduced into the mixed liquid, comprising:

[0068] Use activated carbon to adsorb flue gas generated by solid waste incineration power plants;

[0069] The adsorbed flue gas is introduced into the mixed liquid.

[0070] In this embodiment, carbon black is activated with calcium hydroxide and then sprayed back to the solid waste incineration power plant to adsorb heavy metals and harmful organic matter from the flue gas generated by the solid waste incineration power plant, thereby facilitating net zero emissions of flue gas from the solid waste incineration power plant.

[0071] The above describes specific embodiments of the present invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0072] The various embodiments of the present invention are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0073] It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating fly ash from solid waste incineration, characterized in that: include: Determine the actual proportion of soluble salts in the solid waste incineration fly ash to be treated; When the actual ratio is greater than the preset ratio, the following steps are performed: the target solvent is mixed with the solid waste incineration fly ash to be treated and centrifuged to obtain an organic layer, a carbon black layer, an inorganic layer and an ash layer distributed from top to bottom; the organic layer, the carbon black layer, the inorganic layer and the ash layer are separated respectively to obtain organic components, carbon black, brine and elution ash that can be recycled in turn; wherein the ratio of soluble salts in the solution after the target solvent and the solid waste incineration fly ash to be treated is between 10% and 20%; When the actual ratio is not greater than the preset ratio, the following steps are performed: the target solvent, the solid waste incineration fly ash to be treated and the first soluble salt are mixed and centrifuged to obtain a liquid phase layer, a carbon black layer and an ash layer distributed from top to bottom; the liquid phase layer, the carbon black layer and the ash layer are separated respectively to obtain a liquid phase layer to be treated, recyclable carbon black and eluted ash in sequence; a second soluble salt is added to the liquid phase layer to be treated to obtain organic components and brine that can be recycled; wherein the proportion of soluble salts in the solution after the target solvent, the solid waste incineration fly ash to be treated and the first soluble salt are mixed is between 10% and 20%; The preset ratio is any value between 40% and 50%, the target solvent includes an organic component and an inorganic component, the organic component includes isopropanol and ethanol, the inorganic component includes a target carbonate and water, and the target carbonate includes sodium carbonate and / or potassium carbonate.

2. The method for treating solid waste incineration fly ash according to claim 1, characterized in that: The isopropanol accounts for 50% to 90% of the organic component, and the ethanol accounts for 10% to 50% of the organic component.

3. The method for treating solid waste incineration fly ash according to claim 1, characterized in that: The organic component accounts for 20% to 90% of the target solvent, and the inorganic component accounts for 10% to 80% of the target solvent.

4. The method for treating fly ash from solid waste incineration according to claim 1, characterized in that: The first soluble salt and the second soluble salt both include sodium salt and / or potassium salt.

5. The method for treating solid waste incineration fly ash according to claim 1, characterized in that: After obtaining the recyclable organic components, it also includes: The recyclable organic component is distilled to obtain the organic component and water used as the target solvent.

6. The method for treating solid waste incineration fly ash according to any one of claims 1 to 5, characterized in that: After obtaining the recyclable brine, it also includes: The recyclable brine is subjected to heating treatment, cooling crystallization and evaporation crystallization in sequence to obtain calcium hydroxide, the target carbonate, chloride salt and water in sequence; wherein the target carbonate and water are used as inorganic components in the target solvent, and the chloride salt is used as the second soluble salt.

7. The method for treating fly ash from solid waste incineration according to claim 6, characterized in that: The temperature of the heating treatment is 40-50°C, and the temperature of the cooling crystallization is 20-30°C.

8. The method for treating fly ash from solid waste incineration according to claim 6, characterized in that: After obtaining the recyclable organic components, carbon black and brine, it also includes: The recyclable carbon black is dried, and the dried carbon black is activated by the calcium hydroxide to obtain activated carbon.

9. The method for treating fly ash from solid waste incineration according to claim 8, characterized in that: Also includes: When the target solvent and the solid waste incineration fly ash to be treated are mixed or when the target solvent, the solid waste incineration fly ash to be treated and the first soluble salt are mixed, the flue gas generated by the solid waste incineration power plant is introduced into the mixed liquid.

10. The method for treating fly ash from solid waste incineration according to claim 9, characterized in that: The method of introducing the flue gas generated by the solid waste incineration power plant into the mixed liquid comprises: Using the activated carbon to adsorb flue gas generated by a solid waste incineration power plant; The adsorbed flue gas is introduced into the mixed liquid.

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