Flotation method and system for dirt removal and calcium conservation of waste incineration fly ash

Abstract

The invention relates to the technical field of solid waste treatment, in particular to a flotation method and system for waste incineration fly ash decontamination and calcium conservation. The method comprises the steps that waste incineration fly ash is placed in a natural environment to be subjected to a natural carbonation reaction till the pH value is 7-9, pretreated fly ash is obtained and mixed with water, and then a collecting agent and a foaming agent are added for flotation separation; or mixing the waste fly ash by using the sulfuric acid aqueous solution as the flotation liquid, and then adding the collecting agent and the foaming agent for flotation separation; wherein the collecting agent is one or more of butyl xanthate, ammonium dibutyl dithiophosphate and N, N-diethyldithiocarbamate. By means of the method, heavy metal and chlorine salt in the fly ash can be removed, Ca-based components in the fly ash can be reserved, and therefore resource utilization of the waste incineration fly ash is achieved to the maximum extent.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste treatment, and in particular to a flotation method and system for decontamination and calcium retention of fly ash from garbage incineration. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] Waste incineration fly ash is a fine particle produced during the incineration process. It contains a large amount of pollutants such as heavy metals and chloride salts and is classified as hazardous waste. At present, the treatment methods for waste incineration fly ash mainly include cement solidification, melt solidification, chemical stabilization, etc. However, these methods have problems such as high treatment cost, low resource utilization rate, and easy to cause secondary pollution.

[0004] In recent years, flotation, as an efficient physical separation technology, has received extensive attention and application in the field of waste incineration fly ash treatment. This technology can effectively separate heavy metals and chloride salts in fly ash through differences in surface chemical properties, which not only achieves fly ash reduction treatment, but also provides a new way for its resource utilization. However, traditional flotation methods still face significant challenges in the treatment of waste incineration fly ash, among which the most prominent is the recycling of calcium. Waste incineration fly ash usually contains a large amount of calcium in the form of calcium oxide, calcium hydroxide, etc. These calcium resources have important application value in cement manufacturing, building materials production and other fields. However, existing fly ash treatment processes often find it difficult to achieve efficient recovery of calcium, resulting in the waste of this precious resource, which has become one of the key bottlenecks restricting the resource utilization of fly ash. Summary of the invention

[0005] In order to overcome the deficiencies in the prior art, the purpose of the present invention is to provide a flotation method and system for decontamination and calcium retention of waste incineration fly ash, which can not only remove heavy metals and chloride salts from fly ash, but also retain Ca-based components in fly ash, thereby realizing the resource utilization of waste incineration fly ash to the greatest extent.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] In the first aspect, a flotation method for decontamination and calcium retention of waste incineration fly ash is provided, wherein the waste incineration fly ash is placed in a natural environment for natural carbonation reaction, and the pH value is reacted to 7-9 to obtain pretreated fly ash, and the pretreated fly ash is mixed with water, and then a collector and a frother are added for flotation separation; wherein the collector is one or more of butyl xanthate, butyl ammonium black medicine, and ethyl thiocyanate.

[0008] In the process of natural carbonation reaction, CaO, Ca(OH)2 and other Ca-based components in the fly ash react with CO2 in the air to generate CaCO3, and at the same time, some heavy metal ions in the fly ash also react with CO2 to generate carbonate precipitation, thereby achieving the initial stabilization of heavy metals. In the flotation process, through the selection of collectors, heavy metals (such as Pb, Zn, Cd, etc.) can be captured in a targeted manner and attached to bubbles, and are captured and floated by the bubbles to form foam products, which are scum after solid-liquid separation, and at the same time, Ca-based components in the fly ash such as (such as CaCO3, etc.) are left at the bottom of the flotation tank to form tailings. The present invention realizes the removal of heavy metals and chloride salts in fly ash and the retention of Ca-based components through the coordinated cooperation of the natural carbonation reaction process and the collector in the flotation process.

[0009] In a second aspect, a flotation system for decontamination and calcium retention of waste incineration fly ash is provided, which is used to implement the flotation method described in the first aspect of the present invention, comprising:

[0010] A pretreatment device, configured to allow waste incineration fly ash to undergo a natural carbonation reaction in a natural environment;

[0011] a flotation device configured to perform flotation separation on the material from the pre-treatment device;

[0012] a collector storage tank configured to add collector to the flotation device;

[0013] a conditioning agent storage tank configured to add conditioning agent to the flotation device;

[0014] The frother storage tank is configured to add the frother into the flotation device.

[0015] In the third aspect, a flotation method for decontamination and calcium retention of waste incineration fly ash is provided, wherein the waste fly ash is mixed with an aqueous sulfuric acid solution as the flotation liquid, and then a collector and a frother are added for flotation separation; wherein the collector is one or more of butyl xanthate, butyl ammonium black medicine, and ethylthiocyanate.

[0016] The present invention selects sulfuric acid aqueous solution as flotation liquid, that is, sulfuric acid is added to water, and the pH value in the flotation process is controlled, so that part of the insoluble and insoluble chloride salts in the fly ash are removed, and calcium sulfate slightly soluble in water is generated, so that the Ca-based components can be retained; in the flotation process, through the selection of collectors, heavy metals (such as Pb, Zn, Cd, etc.) can be captured and attached to bubbles, and are captured and floated by bubbles to form foam products, which are scum after solid-liquid separation, and the Ca-based components (such as calcium carbonate, calcium sulfate, etc.) in the fly ash are left at the bottom of the flotation tank to form tailings. The present invention realizes the removal of heavy metals and chloride salts in fly ash and the retention of Ca-based components by selecting sulfuric acid aqueous solution as flotation liquid and cooperating with collectors in the flotation process.

[0017] In a fourth aspect, a flotation system for decontamination and calcium retention of waste incineration fly ash is provided, which is used to implement the flotation method described in the third aspect of the present invention, comprising:

[0018] a sulfuric acid storage tank configured to add sulfuric acid to the flotation unit;

[0019] A flotation device, configured to perform flotation separation on waste incineration fly ash;

[0020] a collector storage tank configured to add collector to the flotation device;

[0021] a conditioning agent storage tank configured to add conditioning agent to the flotation device;

[0022] The frother storage tank is configured to add the frother into the flotation device.

[0023] A fifth aspect provides a fly ash tailings obtained by the flotation method described in the first aspect of the present invention or the flotation method described in the third aspect of the present invention.

[0024] A sixth aspect is a use of the fly ash tailings described in the fifth aspect of the present invention in the preparation of building materials.

[0025] The beneficial effects of the present invention are:

[0026] 1. The present invention firstly performs a suitable acidification treatment on the fly ash, which can not only convert calcium ions into precipitates or components slightly soluble in water, but also release chloride ions in the fly ash. Specifically, the suitable acidification treatment includes natural carbonation pretreatment and selecting a sulfuric acid aqueous solution as a flotation liquid, wherein the natural carbonation pretreatment utilizes carbon dioxide in the air, does not require the addition of additional chemical reagents, is low in cost, and does not cause secondary pollution; the sulfuric acid aqueous solution is selected as the flotation liquid, and the pH value of the experimental endpoint is controlled by directly adding sulfuric acid, so that some of the insoluble and insoluble chloride salts (Friedel's salts) in the fly ash can be removed, thereby improving the removal effect of the Cl element.

[0027] 2. Compared with traditional fly ash flotation, the present invention adopts mineral processing agent as collector to efficiently capture multiple heavy metals such as Pb, Cd, Cu, Zn in fly ash at the same time, increase the heavy metal content in slag, and effectively reduce the heavy metal leaching concentration in tailings. At the same time, combined with fly ash acidification treatment, it can realize efficient separation of calcium resources and pollutants in fly ash, obtain calcium carbonate products with low heavy metal content, and improve the resource utilization rate of fly ash.

[0028] 3. The present invention can effectively remove heavy metals and chloride salts in fly ash from waste incineration while retaining Ca-based components in the fly ash, thereby achieving harmless treatment and resource utilization of fly ash. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0030] Figure 1 This is a flow chart of the flotation method for decontamination and calcium retention of waste incineration fly ash according to Examples 1 to 8 of the present invention;

[0031] Figure 2 This is a flow chart of the flotation method for decontamination and calcium retention of waste incineration fly ash of Examples 9 to 12 of the present invention. DETAILED DESCRIPTION

[0032] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] The flotation described in the present invention refers to the process of separating harmful components from beneficial components in the slurry through flotation agents and aeration stirring. The solid obtained after the ash-containing foam scraped out during flotation is filtered and dried is called scum, the solution obtained after the slurry after flotation is filtered is called flotation waste liquid, and the solid obtained is called tailings.

[0035] Considering that the heavy metals present in fly ash will cause leaching when it comes into contact with water during its use as building materials, causing secondary pollution, and the chlorine present in fly ash will cause corrosion damage to instruments and equipment during its co-treatment in cement kilns, thereby affecting the resource recycling of fly ash, the present invention proposes a flotation method and system for decontamination and calcium retention of waste incineration fly ash.

[0036] A typical embodiment of the present invention provides a flotation method for decontamination and calcium retention of waste incineration fly ash, wherein the waste incineration fly ash is placed in a natural environment for natural carbonation reaction, and the pH value is reacted to 7-9 to obtain pretreated fly ash, and the pretreated fly ash is mixed with water, and then a collector and a frother are added for flotation separation; wherein the collector is one or more of butyl xanthate, butyl ammonium black medicine, and ethyl thiocyanate.

[0037] In some embodiments, the natural carbonation reaction time is 5 to 7 days.

[0038] In some embodiments, during the flotation process, the liquid-to-solid ratio of water to pretreated fly ash is 9-11:1, L / kg.

[0039] In some embodiments, during the flotation process, the flow rate of air is 200-400 L / h, and the time of air introduction is 5-15 min.

[0040] In some embodiments, the mass ratio of pretreated fly ash to collector is 100:0.05-1.10. When the collector is ethylthiocyanate, the mass ratio of pretreated fly ash to collector is 100:0.05-0.10. When the collector is butyl xanthate and butyl ammonium black medicine, the mass ratio of pretreated fly ash to collector is 100:0.90-1.00. The mass ratio of butyl xanthate and butyl ammonium black medicine is 0.9-1.0:1.

[0041] In some embodiments, the foaming agent is sodium lauryl sulfate.

[0042] In some embodiments, the mass ratio of pretreated fly ash to foaming agent is 100:0.03-0.05.

[0043] In some embodiments, a regulator needs to be added during the flotation separation process. Specifically, the regulator is sodium sulfide. Specifically, the mass ratio of the pretreated fly ash to the regulator is 100: 0.09-0.11.

[0044] Another embodiment of the present invention provides a flotation system for waste incineration fly ash decontamination and calcium retention, which is used to implement the above flotation method, including:

[0045] A pretreatment device, configured to allow waste incineration fly ash to undergo a natural carbonation reaction in a natural environment;

[0046] a flotation device configured to perform flotation separation on the material from the pre-treatment device;

[0047] a collector storage tank configured to add collector to the flotation device;

[0048] a conditioning agent storage tank configured to add conditioning agent to the flotation device;

[0049] The frother storage tank is configured to add the frother into the flotation device.

[0050] The third embodiment of the present invention provides a flotation method for decontamination and calcium retention of waste incineration fly ash, wherein the waste fly ash is mixed with an aqueous sulfuric acid solution as the flotation liquid, and then a collector and a frother are added for flotation separation; wherein the collector is one or more of butyl xanthate, butyl ammonium black medicine, and ethylthiocyanate.

[0051] In some embodiments, 20-22 mL of 98% sulfuric acid is added for every 100 g of fly ash. By calculating the acid neutralization capacity of fly ash, the amount of H2O that the fly ash needs to consume when the pH value of the system is 7 can be calculated. + The amount of substance in the fly ash is used to calculate the mass of sulfuric acid required. The theoretical calculation formula for fly ash acid neutralization capacity (ANC) is as follows:

[0052]

[0053] Where ANC is the value of the acid neutralization capacity of fly ash; is the mass fraction of Al2O3 in fly ash (%); is the mass fraction of Fe2O3 in fly ash (%); ω CaP is the mass fraction of CaO in fly ash (%); ω MgP is the mass fraction of MgO in fly ash (%); is the mass fraction of K2O in fly ash (%); is the mass fraction of Na2O in fly ash (%); is the mass fraction of SO3 in fly ash (%); is the mass fraction (%) of H2SO4 in fly ash.

[0054] When calculating the amount of sulfuric acid to be added, the final pH value of the flotation system is 7, assuming that sulfuric acid is completely electrolyzed in water. + The amount of material needs to be equal to the ANC of the fly ash. The mass of sulfuric acid required per gram of fly ash is calculated as follows:

[0055]

[0056] Where m is the mass of sulfuric acid required per gram of fly ash (g); ANC is the acid neutralization capacity of fly ash.

[0057] Integrating the above two formulas and converting the units, we can get the mass of sulfuric acid that needs to be added per kilogram of fly ash:

[0058]

[0059] Where ANC is the value of the acid neutralization capacity of fly ash; is the mass fraction of Al2O3 in fly ash (%); is the mass fraction of Fe2O3 in fly ash (%); ω CaP is the mass fraction of CaO in fly ash (%); ω MgO is the mass fraction of MgO in fly ash (%); is the mass fraction of K2O in fly ash (%); is the mass fraction of Na2O in fly ash (%); is the mass fraction of SO3 in fly ash (%); is the mass fraction (%) of H2SO4 in fly ash.

[0060] In some embodiments, during the flotation process, the liquid-to-solid ratio of the flotation liquid to the pretreated fly ash is 9-11:1, L / kg.

[0061] In some embodiments, during the flotation process, the flow rate of air is 200-400 L / h, and the time of air introduction is 5-15 min.

[0062] In some embodiments, the mass ratio of pretreated fly ash to collector is 100:0.05-1.10. When the collector is ethylthiocyanate, the mass ratio of pretreated fly ash to collector is 100:0.05-0.10. When the collector is butyl xanthate and butyl ammonium black medicine, the mass ratio of pretreated fly ash to collector is 100:0.90-1.00. The mass ratio of butyl xanthate and butyl ammonium black medicine is 0.9-1.0:1.

[0063] In some embodiments, the foaming agent is sodium lauryl sulfate.

[0064] In some embodiments, the mass ratio of pretreated fly ash to foaming agent is 100:0.03-0.05.

[0065] In some embodiments, a regulator needs to be added during the flotation separation process. Specifically, the regulator is sodium sulfide. Specifically, the mass ratio of the pretreated fly ash to the regulator is 100:0.09-0.11.

[0066] A fourth embodiment of the present invention provides a flotation system for waste incineration fly ash decontamination and calcium retention, which is used to implement the above flotation method, including:

[0067] a sulfuric acid storage tank configured to add sulfuric acid to the flotation unit;

[0068] A flotation device, configured to perform flotation separation on waste incineration fly ash;

[0069] a collector storage tank configured to add collector to the flotation device;

[0070] a conditioning agent storage tank configured to add conditioning agent to the flotation device;

[0071] The frother storage tank is configured to add the frother into the flotation device.

[0072] A fifth embodiment of the present invention provides a fly ash tailing obtained by the above flotation method.

[0073] A sixth embodiment of the present invention provides a use of the fly ash tailings described above in the present invention in preparing building materials.

[0074] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with specific embodiments.

[0075] Example 1

[0076] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 1 As shown, the steps are as follows:

[0077] (1) The waste incineration fly ash is placed in a natural environment and exposed to air for a natural carbonation reaction for 5 days to achieve mild carbonation treatment.

[0078] (2) After the fly ash pretreated by natural carbonation is dried and crushed, 100 g of the sample is weighed, deionized water is added at a liquid-to-solid ratio of 10:1 (L / kg), and the sample is placed in a flotation tank and stirred at a speed of 300 r / min for 10 min to fully wet the fly ash and obtain a uniform slurry.

[0079] (3) Add 0.46g of butyl xanthate and 0.50g of butyl ammonium black medicine to the mortar, stir thoroughly to mix, and then add 0.04g of sodium dodecyl sulfate for a second stirring to ensure that the agents are evenly dispersed.

[0080] (4) Turn on the aeration device and introduce air at a constant flow rate of 300 L / h while maintaining stirring.

[0081] (5) Immediately after aeration, use a scraper to collect the ash-containing foam. After continuous aeration for 10 minutes, stop aeration and stirring, and collect the ash-containing foam and tail slurry separately.

[0082] (6) The two products are separated into solid and liquid by a suction filtration device. The solid product obtained after the ash-containing foam is filtered is recorded as scum, and the solid product obtained after the tailing slurry is filtered is recorded as tailing. The liquid generated during the filtration process is collected as flotation waste liquid.

[0083] The tailings were prepared into a leachate according to the Horizontal Oscillation Method for Toxicity Leaching of Solid Waste (HJ 557-2010), and the heavy metal concentration in the leachate was detected by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The tailings were prepared into a tailings digestate according to the hot plate digestion method in the Inductively Coupled Plasma Optical Emission Spectrometry for the Determination of Metal Elements in Solid Waste (HJ 766-2015), and the Ca content in the tailings digestate and the Ca loss in the flotation waste liquid were detected by the EDTA Titration Method for the Determination of Calcium in Water Quality (GB 7476-1987). According to the Silver Nitrate Titration Method for the Determination of Chloride in Water Quality (GB

[0084] 11896-1989) standard for testing the soluble chlorine content in tailings.

[0085] Example 2

[0086] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 1 As shown, the steps are as follows:

[0087] (1) The waste incineration fly ash is placed in a natural environment and exposed to air for a natural carbonation reaction for 5 days to achieve mild carbonation treatment.

[0088] (2) After the fly ash pretreated by natural carbonation is dried and crushed, 100 g of the sample is weighed, deionized water is added at a liquid-to-solid ratio of 10:1 (L / kg), and the sample is placed in a flotation tank and stirred at a speed of 300 r / min for 10 min to fully wet the fly ash and obtain a uniform slurry.

[0089] (3) Add 0.07 g of ethyl thiocyanate to the mortar, stir thoroughly, and then add 0.04 g of sodium dodecyl sulfate for a second stirring to ensure that the agent is evenly dispersed.

[0090] (4) Turn on the aeration device and introduce air at a constant flow rate of 300 L / h while maintaining stirring.

[0091] (5) Immediately after aeration, use a scraper to collect the ash-containing foam. After continuous aeration for 10 minutes, stop aeration and stirring, and collect the ash-containing foam and tail slurry separately.

[0092] (6) The two products are separated into solid and liquid by a suction filtration device. The solid product obtained after the ash-containing foam is filtered is recorded as scum, and the solid product obtained after the tailing slurry is filtered is recorded as tailing. The liquid generated during the filtration process is collected as flotation waste liquid.

[0093] The tailings were prepared into leaching solution according to the HJ 557-2010 method, and the heavy metal concentration in the leaching solution was detected by ICP-OES. The tailings were prepared into tailings digestion solution according to the hot plate digestion method in HJ 766-2015, and the Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0094] Example 3

[0095] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 1 As shown, the steps are as follows:

[0096] (1) The waste incineration fly ash is placed in a natural environment and exposed to air for a natural carbonation reaction for 5 days to achieve mild carbonation treatment.

[0097] (2) After the fly ash pretreated by natural carbonation is dried and crushed, 100 g of the sample is weighed, deionized water is added at a liquid-to-solid ratio of 10:1 (L / kg), and the sample is placed in a flotation tank and stirred at a speed of 300 r / min for 10 min to fully wet the fly ash and obtain a uniform slurry.

[0098] (3) Add 0.07 g of ethyl thiocyanate, 0.46 g of butyl xanthate and 0.50 g of butyl ammonium black medicine to the mortar, stir thoroughly and then add 0.04 g of sodium dodecyl sulfate for a second stirring to ensure that the agents are evenly dispersed.

[0099] (4) Turn on the aeration device and introduce air at a constant flow rate of 300 L / h while maintaining stirring.

[0100] (5) Immediately after aeration, use a scraper to collect the ash-containing foam. After continuous aeration for 10 minutes, stop aeration and stirring, and collect the ash-containing foam and tail slurry separately.

[0101] (6) The two products are separated into solid and liquid by a suction filtration device. The solid product obtained after the ash-containing foam is filtered is recorded as scum, and the solid product obtained after the tailing slurry is filtered is recorded as tailing. The liquid generated during the filtration process is collected as flotation waste liquid.

[0102] The tailings were prepared into leaching solution according to the HJ 557-2010 method, and the heavy metal concentration in the leaching solution was detected by ICP-OES. The tailings were prepared into tailings digestion solution according to the hot plate digestion method in HJ 766-2015, and the Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0103] Example 4

[0104] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 1 As shown, the steps are as follows:

[0105] (1) The waste incineration fly ash is placed in a natural environment and exposed to air for a natural carbonation reaction for 5 days to achieve mild carbonation treatment.

[0106] (2) After the fly ash pretreated by natural carbonation is dried and crushed, 100 g of the sample is weighed, deionized water is added at a liquid-to-solid ratio of 10:1 (L / kg), and the sample is placed in a flotation tank and stirred at a speed of 300 r / min for 10 min to fully wet the fly ash and obtain a uniform slurry.

[0107] (3) Add 0.10 g of sodium sulfide to the mortar and stir for 2 min. Then add 0.07 g of ethyl dithiocarbamide, 0.46 g of butyl xanthate and 0.50 g of butyl ammonium black medicine. After fully stirring and mixing, add 0.04 g of sodium dodecyl sulfate and stir again to ensure that the agents are evenly dispersed.

[0108] (4) Turn on the aeration device and introduce air at a constant flow rate of 300 L / h while maintaining the stirring state;

[0109] (5) Immediately after aeration, use a scraper to collect the ash-containing foam. After continuous aeration for 10 minutes, stop aeration and stirring, and collect the ash-containing foam and tail slurry separately.

[0110] (6) The two products are separated into solid and liquid by a suction filtration device. The solid product obtained after the ash-containing foam is filtered is recorded as scum, and the solid product obtained after the tailing slurry is filtered is recorded as tailing. The liquid generated during the filtration process is collected as flotation waste liquid.

[0111] The tailings were prepared into leaching solution according to the HJ 557-2010 method, and the heavy metal concentration in the leaching solution was detected by ICP-OES. The tailings were prepared into tailings digestion solution according to the hot plate digestion method in HJ 766-2015, and the Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0112] Example 5

[0113] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 1 As shown, the steps are as follows:

[0114] (1) The waste incineration fly ash is placed in a natural environment and exposed to air for a natural carbonation reaction for 7 days to achieve severe carbonation treatment.

[0115] (2) After the fly ash pretreated by natural carbonation is dried and crushed, 100 g of the sample is weighed, deionized water is added at a liquid-to-solid ratio of 10:1 (L / kg), and the sample is placed in a flotation tank and stirred at a speed of 300 r / min for 10 min to fully wet the fly ash and obtain a uniform slurry.

[0116] (3) Add 0.46g of butyl xanthate and 0.50g of butyl ammonium black medicine to the mortar, stir thoroughly to mix, and then add 0.04g of sodium dodecyl sulfate for a second stirring to ensure that the agents are evenly dispersed.

[0117] (4) Turn on the aeration device and introduce air at a constant flow rate of 300 L / h while maintaining the stirring state;

[0118] (5) Immediately after aeration, use a scraper to collect the ash-containing foam. After continuous aeration for 10 minutes, stop aeration and stirring, and collect the ash-containing foam and tail slurry separately.

[0119] (6) The two products are separated into solid and liquid by a suction filtration device. The solid product obtained after the ash-containing foam is filtered is recorded as scum, and the solid product obtained after the tailing slurry is filtered is recorded as tailing. The liquid generated during the filtration process is collected as flotation waste liquid.

[0120] The tailings were prepared into leaching solution according to the HJ 557-2010 method, and the heavy metal concentration in the leaching solution was detected by ICP-OES. The tailings were prepared into tailings digestion solution according to the hot plate digestion method in HJ 766-2015, and the Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0121] Example 6

[0122] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 1 As shown, the steps are as follows:

[0123] (1) The waste incineration fly ash is placed in a natural environment and exposed to air for a natural carbonation reaction for 7 days to achieve severe carbonation treatment.

[0124] (2) After the fly ash pretreated by natural carbonation is dried and crushed, 100 g of the sample is weighed, deionized water is added at a liquid-to-solid ratio of 10:1 (L / kg), and the sample is placed in a flotation tank and stirred at a speed of 300 r / min for 10 min to fully wet the fly ash and obtain a uniform slurry.

[0125] (3) Add 0.07 g of ethyl thiocyanate to the mortar, stir thoroughly, and then add 0.04 g of sodium dodecyl sulfate for a second stirring to ensure that the agent is evenly dispersed.

[0126] (4) Turn on the aeration device and introduce air at a constant flow rate of 300 L / h while maintaining the stirring state;

[0127] (5) Immediately after aeration, use a scraper to collect the ash-containing foam. After continuous aeration for 10 minutes, stop aeration and stirring, and collect the ash-containing foam and tail slurry separately.

[0128] (6) The two products are separated into solid and liquid by a suction filtration device. The solid product obtained after the ash-containing foam is filtered is recorded as scum, and the solid product obtained after the tailing slurry is filtered is recorded as tailing. The liquid generated during the filtration process is collected as flotation waste liquid.

[0129] The tailings were prepared into leaching solution according to the HJ 557-2010 method, and the heavy metal concentration in the leaching solution was detected by ICP-OES. The tailings were prepared into tailings digestion solution according to the hot plate digestion method in HJ 766-2015, and the Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0130] Example 7

[0131] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 1 As shown, the steps are as follows:

[0132] (1) The waste incineration fly ash is placed in a natural environment and exposed to air for a natural carbonation reaction for 7 days to achieve severe carbonation treatment.

[0133] (2) After the fly ash pretreated by natural carbonation is dried and crushed, 100 g of the sample is weighed, deionized water is added at a liquid-to-solid ratio of 10:1 (L / kg), and the sample is placed in a flotation tank and stirred at a speed of 300 r / min for 10 min to fully wet the fly ash and obtain a uniform slurry.

[0134] (3) Add 0.07 g of ethyl thiocyanate, 0.46 g of butyl xanthate and 0.50 g of butyl ammonium black medicine to the mortar, stir thoroughly and then add 0.04 g of sodium dodecyl sulfate for a second stirring to ensure that the agents are evenly dispersed.

[0135] (4) Turn on the aeration device and introduce air at a constant flow rate of 300 L / h while maintaining stirring.

[0136] (5) Immediately after aeration, use a scraper to collect the ash-containing foam. After continuous aeration for 10 minutes, stop aeration and stirring, and collect the ash-containing foam and tail slurry separately.

[0137] (6) The two products are separated into solid and liquid by a suction filtration device. The solid product obtained after the ash-containing foam is filtered is recorded as scum, and the solid product obtained after the tailing slurry is filtered is recorded as tailing. The liquid generated during the filtration process is collected as flotation waste liquid.

[0138] The tailings were prepared into leaching solution according to the HJ 557-2010 method, and the heavy metal concentration in the leaching solution was detected by ICP-OES. The tailings were prepared into tailings digestion solution according to the hot plate digestion method in HJ 766-2015, and the Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0139] Example 8

[0140] A flotation method for decontamination and calcium retention of waste incineration fly ash, the steps are as follows:

[0141] (1) The waste incineration fly ash is placed in a natural environment and exposed to air for a natural carbonation reaction for 7 days to achieve severe carbonation treatment.

[0142] (2) After the fly ash pretreated by natural carbonation is dried and crushed, 100 g of the sample is weighed, deionized water is added at a liquid-to-solid ratio of 10:1 (L / kg), and the sample is placed in a flotation tank and stirred at a speed of 300 r / min for 10 min to fully wet the fly ash and obtain a uniform slurry.

[0143] (3) Add 0.10 g of sodium sulfide to the mortar and stir for 2 min. Then add 0.07 g of ethyl dithiocarbamide, 0.46 g of butyl xanthate and 0.50 g of butyl ammonium black medicine. After fully stirring and mixing, add 0.04 g of sodium dodecyl sulfate and stir again to ensure that the agents are evenly dispersed.

[0144] (4) Turn on the aeration device and introduce air at a constant flow rate of 300 L / h while maintaining the stirring state;

[0145] (5) Immediately after aeration, use a scraper to collect the ash-containing foam. After continuous aeration for 10 minutes, stop aeration and stirring, and collect the ash-containing foam and tail slurry separately.

[0146] (6) The two products are separated into solid and liquid by a suction filtration device. The solid product obtained after the ash-containing foam is filtered is recorded as scum, and the solid product obtained after the tailing slurry is filtered is recorded as tailing. The liquid generated during the filtration process is collected as flotation waste liquid.

[0147] The tailings were prepared into leaching solution according to the HJ 557-2010 method, and the heavy metal concentration in the leaching solution was detected by ICP-OES. The tailings were prepared into tailings digestion solution according to the hot plate digestion method in HJ 766-2015, and the Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0148] After testing Examples 1 to 8, the data obtained are as follows:

[0149] Table 1 Flotation tailings experimental data table of Examples 1 to 8

[0150]

[0151] According to the data in Table 1, the heavy metal leaching concentration of the flotation tailings of Examples 1 to 8 is better than that of the traditional water-washed fly ash. Among them, the heavy metal leaching concentration of the tailings after flotation fully meets the limit requirements of the "Comprehensive Sewage Discharge Standard" (GB 8978-1996). At the same time, the soluble chlorine content of the tailings is also much lower than that of the traditional water-washed fly ash, and the soluble chlorine content is strictly controlled within the limit range specified in the "Technical Specifications for Pollution Control of Fly Ash from Municipal Waste Incineration" (HJ 1134-2020) (the specification requires that the soluble chlorine content after fly ash pretreatment shall not exceed 2%, preferably not more than 1%). In addition, the Ca loss rate of this method is greatly reduced compared with the traditional water-washing process, and the Ca content in the tailings is higher than that of the traditional water-washed fly ash. This result fully confirms that this method has significant advantages in reducing the loss of Ca-based components.

[0152] Example 9

[0153] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 2 As shown, the steps are as follows:

[0154] (1) Dry the fly ash sample in an oven and weigh 100 g of the dried sample and place it in a flotation tank.

[0155] (2) Add flotation liquid (aqueous sulfuric acid solution, prepared by taking 21 mL of sulfuric acid (mass fraction 98%) and diluting it to 1 L with water) at a liquid-to-solid ratio of 10:1 (L / kg), and stir continuously at a speed of 300 r / min for 10 min to obtain a uniform slurry.

[0156] (3) Add 0.46 g of butyl xanthate and 0.50 g of butyl ammonium black powder to the mortar, stir for 2 min to mix them thoroughly, then add 0.04 g of sodium dodecyl sulfate, a foaming agent, and continue stirring for 30 s to evenly disperse the agents.

[0157] (4) Start the aeration device, introduce air at a constant flow rate of 300 L / h, maintain stirring, and start flotation operation.

[0158] (5) During the flotation process, a scraper is used to collect the ash-containing foam. After continuous ventilation for 10 minutes, the aeration and stirring device is turned off. The ash-containing foam and tailings are collected separately and filtered to achieve solid-liquid separation. The ash-containing foam is filtered to obtain scum, and the tailings are filtered to obtain tailings. The filtrate is the flotation waste liquid.

[0159] The tailings were prepared with leaching solution according to the HJ 557-2010 method, and the scum digestion solution was prepared with the hot plate digestion method in HJ 766-2015. The heavy metal concentration of the tailings leaching solution and the heavy metal content of the scum digestion solution were detected by ICP-OES. The Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0160] Example 10

[0161] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 2 As shown, the steps are as follows:

[0162] (1) Dry the fly ash sample in an oven and weigh 100 g of the dried sample and place it in a flotation tank.

[0163] (2) Add flotation liquid (aqueous sulfuric acid solution, prepared by taking 21 mL of sulfuric acid (mass fraction 98%) and diluting it to 1 L with water) at a liquid-to-solid ratio of 10:1 (L / kg), and stir continuously at a speed of 300 r / min for 10 min to obtain a uniform slurry.

[0164] (3) Add 0.07 g of ethyl dithiocarbamide as a collector to the mortar and stir for 2 min to fully mix it. Then add 0.04 g of sodium dodecyl sulfate as a foaming agent and continue stirring for 30 s to evenly disperse the agent.

[0165] (4) Start the aeration device, introduce air at a constant flow rate of 300 L / h, maintain stirring, and start flotation operation.

[0166] (5) During the flotation process, a scraper is used to collect the ash-containing foam. After continuous ventilation for 10 minutes, the aeration and stirring device is turned off. The ash-containing foam and tailings are collected separately and filtered to achieve solid-liquid separation. The ash-containing foam is filtered to obtain scum, and the tailings are filtered to obtain tailings. The filtrate is the flotation waste liquid.

[0167] The tailings were prepared with leaching solution according to the HJ 557-2010 method, and the scum digestion solution was prepared with the hot plate digestion method in HJ 766-2015. The heavy metal concentration of the tailings leaching solution and the heavy metal content of the scum digestion solution were detected by ICP-OES. The Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0168] Embodiment 11

[0169] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 2As shown, the steps are as follows:

[0170] (1) Dry the fly ash sample in an oven and weigh 100 g of the dried sample and place it in a flotation tank.

[0171] (2) Add flotation liquid (aqueous sulfuric acid solution, prepared by taking 21 mL of sulfuric acid (mass fraction 98%) and diluting it to 1 L with water) at a liquid-to-solid ratio of 10:1 (L / kg), and stir continuously at a speed of 300 r / min for 10 min to obtain a uniform slurry.

[0172] (3) Add 0.46 g of butyl xanthate, 0.50 g of butyl ammonium black powder, and 0.07 g of ethyl thiocyanate to the mortar and stir for 2 min to mix them thoroughly. Then add 0.04 g of sodium dodecyl sulfate, a foaming agent, and continue stirring for 30 s to evenly disperse the agents.

[0173] (4) Start the aeration device, introduce air at a constant flow rate of 300 L / h, maintain stirring, and start flotation operation.

[0174] (5) During the flotation process, a scraper is used to collect the ash-containing foam. After continuous ventilation for 10 minutes, the aeration and stirring device is turned off. The ash-containing foam and tailings are collected separately and filtered to achieve solid-liquid separation. The ash-containing foam is filtered to obtain scum, and the tailings are filtered to obtain tailings. The filtrate is the flotation waste liquid.

[0175] The tailings were prepared with leaching solution according to the HJ 557-2010 method, and the scum digestion solution was prepared with the hot plate digestion method in HJ 766-2015. The heavy metal concentration of the tailings leaching solution and the heavy metal content of the scum digestion solution were detected by ICP-OES. The Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0176] Example 12

[0177] A flotation method for decontamination and calcium retention of waste incineration fly ash, such as Figure 2 As shown, the steps are as follows:

[0178] (1) Dry the fly ash sample in an oven and weigh 100 g of the dried sample and place it in a flotation tank.

[0179] (2) Add flotation liquid (aqueous sulfuric acid solution, prepared by taking 21 mL of sulfuric acid (mass fraction 98%) and diluting it to 1 L with water) at a liquid-to-solid ratio of 10:1 (L / kg), and stir continuously at a speed of 300 r / min for 10 min to obtain a uniform slurry.

[0180] (3) Add 0.1 g of sodium sulfide as a conditioning agent to the mortar and stir for 2 min. Then add 0.46 g of butyl xanthate, 0.50 g of butyl ammonium black medicine and 0.07 g of ethyl thiocyanate as a collector and stir for 2 min to fully mix them. Then add 0.04 g of sodium dodecyl sulfate as a foaming agent and continue stirring for 30 s to evenly disperse the agents.

[0181] (4) Start the aeration device, introduce air at a constant flow rate of 300 L / h, maintain stirring, and start flotation operation.

[0182] (5) During the flotation process, a scraper is used to collect the ash-containing foam. After continuous ventilation for 10 minutes, the aeration and stirring device is turned off. The ash-containing foam and tailings are collected separately and filtered to achieve solid-liquid separation. The ash-containing foam is filtered to obtain scum, and the tailings are filtered to obtain tailings. The filtrate is the flotation waste liquid.

[0183] The tailings were prepared with leaching solution according to the HJ 557-2010 method, and the scum digestion solution was prepared with the hot plate digestion method in HJ 766-2015. The heavy metal concentration of the tailings leaching solution and the heavy metal content of the scum digestion solution were detected by ICP-OES. The Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0184] Example 13

[0185] (1) Dry the fly ash sample in an oven and weigh 100 g of the dried sample and place it in a flotation tank.

[0186] (2) Add flotation liquid (aqueous sulfuric acid solution, prepared by taking 21 mL of sulfuric acid (mass fraction 98%) and diluting it to 1 L with water) at a liquid-to-solid ratio of 10:1 (L / kg), and stir continuously at a speed of 300 r / min for 10 min to obtain a uniform slurry.

[0187] (3) Add 1.25 mL of kerosene as a collector to the mortar and stir for 2 min to mix it thoroughly. Then add 0.15 g of sodium dodecyl sulfate as a foaming agent and continue stirring for 30 s to evenly disperse the agent.

[0188] (4) Start the aeration device, introduce air at a constant flow rate of 300 L / h, maintain stirring, and start flotation operation.

[0189] (5) During the flotation process, a scraper is used to collect the ash-containing foam. After continuous ventilation for 10 minutes, the aeration and stirring device is turned off. The ash-containing foam and tailings are collected separately and filtered to achieve solid-liquid separation. The ash-containing foam is filtered to obtain scum, and the tailings are filtered to obtain tailings. The filtrate is the flotation waste liquid.

[0190] The tailings were prepared with leaching solution according to the HJ 557-2010 method, and the scum digestion solution was prepared with the hot plate digestion method in HJ 766-2015. The heavy metal concentration of the tailings leaching solution and the heavy metal content of the scum digestion solution were detected by ICP-OES. The Ca content in the tailings digestion solution and the Ca loss in the flotation waste liquid were detected according to GB 7476-1987. The soluble chlorine content in the tailings was detected according to GB 11896-1989.

[0191] After testing Examples 9 to 13, the data obtained are as follows:

[0192] Table 2 Flotation tailings experimental data table of Examples 9 to 13

[0193]

[0194] Table 3 Flotation scum experimental data table of Examples 9 to 13

[0195]

[0196] According to the data in Table 2, the heavy metal leaching concentration of the tailings of Examples 9 to 12 meets the limit value requirements of the "Comprehensive Sewage Discharge Standard" (GB 8978-1996), and the soluble chlorine content is also lower than the specified limit value of the "Technical Specification for Pollution Control of Fly Ash from Incineration of Municipal Waste" (HJ1134-2020). It is particularly noteworthy that this method is outstanding in reducing the Ca loss rate, which is lower than the Ca loss rate of conventional flotation, and significantly lower than the Ca loss rate of the traditional water-washed fly ash process (about 40%). The Ca content in the tailings of Examples 9 to 12 is higher than that of Example 13 (conventional flotation), which shows that this method can effectively reduce the loss of Ca-based components and retain them in the tailings. The data in Table 2 further show that the present method has significant advantages in heavy metal enrichment: compared with conventional flotation, the heavy metal content in the slag of Examples 9 to 12 is significantly increased, among which the enrichment effect of Zn is increased by 79.5%, the enrichment effect of Pb is increased by 270.0%, and the enrichment effect of Cd is significantly increased by 1472.6%, which fully confirms the superiority of the present method.

[0197] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A flotation method for decontamination and calcium retention of fly ash from garbage incineration, characterized in that: The waste incineration fly ash is placed in a natural environment for natural carbonation reaction until the pH value reaches 7-9 to obtain pretreated fly ash. After the pretreated fly ash is mixed with water, a collector and a frother are added for flotation separation; wherein the collector is one or more of butyl xanthate, butyl ammonium black medicine, and ethyl thiocyanate.

2. The flotation method according to claim 1, characterized in that: The natural carbonation reaction time is 5 to 7 days.

3. A flotation system for waste incineration fly ash decontamination and calcium retention, characterized in that: The flotation method according to claim 1 comprises: A pretreatment device, configured to allow waste incineration fly ash to undergo a natural carbonation reaction in a natural environment; a flotation device configured to perform flotation separation on the material from the pre-treatment device; a collector storage tank configured to add collector to the flotation device; a conditioning agent storage tank configured to add conditioning agent to the flotation device; The frother storage tank is configured to add the frother into the flotation device.

4. A flotation method for decontamination and calcium retention of fly ash from garbage incineration, characterized in that: After the garbage fly ash is mixed with sulfuric acid aqueous solution as the flotation liquid, a collector and a frother are added for flotation separation; wherein the collector is one or more of butyl xanthate, butyl ammonium black medicine, and ethyl thiocyanate.

5. The flotation method according to claim 4, characterized in that: For every 100 g of fly ash treated, 20 to 22 mL of 98% sulfuric acid was added.

6. The flotation method according to claim 1 or 4, characterized in that: During the flotation process, the liquid-to-solid ratio of the flotation liquid to the pretreated fly ash was 9-11:1, L / kg; Alternatively, during the flotation process, the air flow rate is 200 to 400 L / h, and the air introduction time is 5 to 15 minutes.

7. The flotation method according to claim 1 or 4, characterized in that: The mass ratio of pretreated fly ash to collector is 100:0.05-1.10; Or, the foaming agent is sodium lauryl sulfate; Or, the mass ratio of pretreated fly ash to foaming agent is 100:0.03-0.05; Alternatively, during the flotation separation process, a regulator needs to be added; preferably, the regulator is sodium sulfide; preferably, the mass ratio of the pretreated fly ash to the regulator is 100:0.09-0.

11.

8. A flotation system for waste incineration fly ash decontamination and calcium retention, used to implement the flotation method of claim 4, comprising: a sulfuric acid storage tank configured to add sulfuric acid to the flotation unit; A flotation device, configured to perform flotation separation on waste incineration fly ash; a collector storage tank configured to add collector to the flotation device; a conditioning agent storage tank configured to add conditioning agent to the flotation device; The frother storage tank is configured to add the frother into the flotation device.

9. A fly ash tailings, characterized in that: Obtained by the flotation method described in any one of claims 1 to 2 and 4 to 7.

10. Use of the fly ash tailings according to claim 9 in preparing building materials.

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