Material proportioning method suitable for heat treatment of waste incineration fly ash

Abstract

The invention relates to the technical field of heat treatment of waste incineration fly ash, in particular to a material proportioning method suitable for heat treatment of waste incineration fly ash. According to the technical scheme, the contents of alkaline calcium and a first target oxide in the waste incineration fly ash to be proportioned and the content of a second target oxide in a fluxing agent to be proportioned are respectively measured to obtain a first measurement result and a second measurement result, and then the mixed alkalinity is determined based on the first measurement result and the second measurement result. And finally, determining the ratio of the waste incineration fly ash to the fluxing agent based on the mixing alkalinity. Therefore, according to the technical scheme, the mixing proportion of the waste incineration fly ash and the fluxing agent can be reasonably calculated, so that the stability of the heat treatment temperature of the fly ash is realized, and the uniformity of the composition of a heat treatment product is improved.

Description

Technical Field

[0001] The invention relates to the technical field of heat treatment of waste incineration fly ash, and in particular to a material proportioning method suitable for heat treatment of waste incineration fly ash. Background Art

[0002] High-temperature heat treatment technology can effectively achieve the detoxification and resource utilization of waste incineration fly ash. When waste incineration fly ash is subjected to high-temperature heat treatment, the proportion of oxides of elements such as silicon, aluminum, and calcium contained in it often determines the melting temperature of the material.

[0003] However, since the waste incineration fly ash contains a large amount of chloride (such as sodium chloride, potassium chloride, calcium chloride, etc.), this will cause the measured ratio of silicon-aluminum-calcium oxides (i.e. calcium oxide, aluminum oxide and silicon oxide) to deviate greatly from the actual molten product. In addition, the content of calcium in the waste incineration fly ash is affected by the amount of lime slurry sprayed in the semi-dry deacidification process. Overspraying of lime slurry will increase the content of alkaline calcium (i.e. calcium oxide, calcium hydroxide and calcium carbonate) in the fly ash. When the concentration of acidic gas in the flue gas is high, the lime slurry reacts with it more completely, and the content of alkaline calcium-containing substances is reduced, and the content of calcium salts such as calcium chloride is significantly increased. However, these calcium salts will not react with other oxides in the fly ash at high temperatures to form a molten phase. Therefore, the content of alkaline calcium in the waste incineration fly ash will directly affect the formation of the silicon-aluminum-calcium ternary oxide system during high-temperature heat treatment.

[0004] In the related art, when waste incineration fly ash is subjected to high-temperature heat treatment, a flux rich in silicon and aluminum is usually added to balance the content of acid and alkali oxides therein, thereby ensuring that the fly ash can melt at a lower temperature and ensure the stable operation of the system. Therefore, before heat treating the waste incineration fly ash, the content of the oxide components actually involved in melting in the fly ash is measured and the mixing ratio of the fly ash and the flux is reasonably calculated, so as to achieve the stability of the heat treatment temperature of the fly ash and improve the uniformity of the composition of the heat treatment product. Summary of the invention

[0005] The present invention provides a material proportioning method suitable for heat treatment of waste incineration fly ash, which can achieve the stability of the heat treatment temperature of the fly ash and improve the uniformity of the composition of the heat treatment product by reasonably calculating the mixing ratio of the waste incineration fly ash and the flux.

[0006] The embodiment of the present invention provides a material proportioning method suitable for heat treatment of waste incineration fly ash, comprising:

[0007] Determine the contents of basic calcium and a first target oxide in the waste incineration fly ash to be proportioned, and obtain a first determination result; wherein the basic calcium includes calcium oxide, calcium carbonate and calcium hydroxide, and the first target oxide includes aluminum oxide and silicon oxide;

[0008] Determine the content of the second target oxide in the flux to be proportioned to obtain a second determination result; wherein the second target oxide includes calcium oxide, aluminum oxide and silicon oxide;

[0009] determining a mixed alkalinity based on the first measurement result and the second measurement result;

[0010] Based on the mixed alkalinity, the ratio of the waste incineration fly ash and the flux is determined.

[0011] It can be seen from the above scheme that the material proportioning method suitable for heat treatment of waste incineration fly ash provided by the present invention measures the content of basic calcium and the first target oxide in the waste incineration fly ash to be proportioned and the content of the second target oxide in the flux to be proportioned, respectively, to obtain the first measurement result and the second measurement result, and then determines the mixed alkalinity based on the first measurement result and the second measurement result, and finally determines the proportion of waste incineration fly ash and flux based on the mixed alkalinity. Therefore, the above technical scheme can achieve the stability of the heat treatment temperature of the fly ash and improve the uniformity of the composition of the heat treatment product by reasonably calculating the mixing ratio of waste incineration fly ash and flux. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 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.

[0013] Figure 1 A schematic flow chart of a material proportioning method suitable for thermal treatment of waste incineration fly ash provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0015] See also Figure 1 One embodiment of the present invention provides a material proportioning method suitable for heat treatment of waste incineration fly ash, the method comprising:

[0016] Step S1, measuring the contents of basic calcium and the first target oxide in the waste incineration fly ash to be proportioned, and obtaining a first measurement result; wherein the basic calcium includes calcium oxide, calcium carbonate and calcium hydroxide, and the first target oxide includes aluminum oxide and silicon oxide;

[0017] Step S2, measuring the content of the second target oxide in the flux to be proportioned to obtain a second measurement result; wherein the second target oxide includes calcium oxide, aluminum oxide and silicon oxide;

[0018] Step S3, determining the mixed alkalinity based on the first measurement result and the second measurement result;

[0019] Step S4: determining the ratio of the waste incineration fly ash and the flux based on the mixed alkalinity.

[0020] In this embodiment, the content of basic calcium and the first target oxide in the waste incineration fly ash to be proportioned and the content of the second target oxide in the flux to be proportioned are measured respectively to obtain the first measurement result and the second measurement result, and then the mixed alkalinity is determined based on the first measurement result and the second measurement result, and finally the proportion of the waste incineration fly ash and the flux is determined based on the mixed alkalinity. Therefore, the above technical solution can achieve the stability of the fly ash heat treatment temperature and improve the uniformity of the composition of the heat treatment product by reasonably calculating the mixing ratio of the waste incineration fly ash and the flux.

[0021] That is, the above technical scheme detects the content of calcium-containing components that actually participate in the melting reaction in the waste incineration fly ash, and then guides the proportioning of the fly ash before high-temperature heat treatment, thereby solving the problem of the difference between the proportioning composition of the traditional detection method and the actual composition of the fly ash after melting, and avoiding fluctuations in the fly ash melting temperature caused by inaccurate addition of flux.

[0022] In some embodiments, the contents of the first target oxide and the second target oxide are both measured by an XRF spectrometer.

[0023] In one embodiment of the present invention, the content of basic calcium is determined by the following method:

[0024] Determining the content of the first soluble salt that can be dissolved in deionized water in the waste incineration fly ash;

[0025] Determining the content of a second soluble salt in the waste incineration fly ash that is soluble in an acid solution; wherein the acid solution includes at least one of hydrochloric acid and nitric acid;

[0026] The difference between the content of the second soluble salt and the content of the first soluble salt is determined as the content of basic calcium.

[0027] In this embodiment, considering that alkaline calcium mainly includes calcium oxide, calcium carbonate and calcium hydroxide, alkaline calcium is insoluble in water but soluble in acid, so the difference between the content of the obtained second soluble salt and the first soluble salt can be used as the content of alkaline calcium.

[0028] In one embodiment of the present invention, the content of the first soluble salt is determined by:

[0029] Mix the dried waste incineration fly ash with deionized water at 40 to 90° C. in a mass ratio of 1:5 to 1:10;

[0030] The completely dissolved waste incineration fly ash is filtered and dried in sequence to obtain the mass of undissolved fly ash in water;

[0031] The content of the first soluble salt is determined based on the mass of the dried waste incineration fly ash and the mass of the undissolved fly ash in water.

[0032] In this embodiment, the dried waste incineration fly ash is mixed with deionized water at 40 to 90° C. in a mass ratio of 1:5 to 1:10, which can reduce the solubility of calcium hydroxide in the fly ash as much as possible, while increasing the solubility of first soluble salts such as calcium chloride, sodium chloride and potassium chloride.

[0033] Considering that fly ash will continuously absorb water during storage, causing its mass to increase continuously, the water in fly ash is completely removed during high-temperature heat treatment. Therefore, removing the water and crystallization water absorbed by fly ash during storage can obtain a weight reference closer to the fly ash in high-temperature heat treatment state, which helps to improve the accuracy of fly ash proportioning. The fly ash drying process needs to be heated at 400-500℃ for 1-4 hours to obtain a dry fly ash sample, and the moisture content of the fly ash is calculated based on the difference before and after drying.

[0034] In one embodiment of the present invention, the content of the second soluble salt is determined by:

[0035] Mixing the dried waste incineration fly ash with an acid solution at 40 to 90° C. in a mass ratio of 1:5 to 1:10;

[0036] The completely dissolved waste incineration fly ash is filtered and dried in sequence to obtain the mass of the fly ash not dissolved in the acid;

[0037] The content of the second soluble salt is determined based on the mass of the dried waste incineration fly ash and the mass of the undissolved fly ash in the acid.

[0038] In this embodiment, the temperature of the acid solution and the deionized water is controlled to be consistent, which can better ensure the accuracy of the experiment. At the same time, at this temperature, the alkaline calcium in the dried waste incineration fly ash can also be more fully dissolved in the acid solution.

[0039] In some embodiments, generally speaking, the calcium content in fly ash is about 20-40%, so when preparing the acid solution, it is necessary to ensure that the hydrogen ions are absolutely excessive, so as to ensure that the alkaline calcium is completely dissolved in the acid solution. According to the dissolution characteristics of the acid solution, hydrochloric acid and nitric acid are preferably selected in the present invention. In addition, in order to increase the solubility of calcium sulfate in fly ash, ammonium chloride can be added to the acid solution in an amount of 0.04-0.1 mol / L. At the same time, according to the ratio of fly ash to acid solution, the concentration of the acid solution can be set to a volume ratio of 0.2-1%.

[0040] In one embodiment of the present invention, the content of the first soluble salt is determined by:

[0041] The dried waste incineration fly ash was mixed with deionized water at 40-90° C. in mass ratios of 1:20, 1:15, 1:10, and 1:5, respectively;

[0042] The turbidity of the first solution after mixing at each mass ratio is tested respectively, and the obtained turbidity is converted into the mass of fly ash added in the water;

[0043] The four obtained turbidities and the mass of fly ash added to the water are plotted into a first standard curve;

[0044] determining the mass of undissolved fly ash in water based on the first standard curve;

[0045] The content of the first soluble salt is determined based on the mass of the dried waste incineration fly ash and the mass of the undissolved fly ash in water.

[0046] In one embodiment of the present invention, the content of the second soluble salt is determined by:

[0047] The dried waste incineration fly ash is mixed with an acid solution at 40 to 90° C. in a mass ratio of 1:20, 1:15, 1:10, and 1:5, respectively;

[0048] The turbidity of the second solution after mixing at each mass ratio is tested respectively, and the obtained turbidity is converted into the mass of fly ash added to the acid;

[0049] The obtained four turbidities and the mass of fly ash added in the acid are plotted into a second standard curve;

[0050] determining the mass of undissolved fly ash in the acid based on a second standard curve;

[0051] The content of the second soluble salt is determined based on the mass of the dried waste incineration fly ash and the mass of the undissolved fly ash in the acid.

[0052] In one embodiment of the present invention, the content of basic calcium is determined by the following formula:

[0053] C Ca-al =(M H +M fa -M ud-H )*C Ca-H / M fa -(M w +M fa -M ud-w )*C Ca-w / M fa

[0054] In the formula, C Ca-al is the content of alkaline calcium, M H is the mass of the acid solution, M fa is the mass of undried waste incineration fly ash, M ud-H is the mass of fly ash not dissolved in the acid, C Ca-H is the concentration of calcium ions in the acid, M w is the mass of deionized water, M ud-w is the mass of fly ash not dissolved in water, C Ca-w is the concentration of calcium ions in water.

[0055] In this embodiment, the basic calcium content calculated by this method is more accurate than the other two methods, that is, the basic calcium content is equal to the total acid-soluble calcium content minus the water-soluble acidic calcium content.

[0056] In one embodiment of the present invention, the content of basic calcium is determined by the following method:

[0057] The dried waste incineration fly ash is mixed with deionized water at 40 to 90°C and an acid solution at a mass ratio of 1:5;

[0058] The obtained mixed solution was filtered, and the mixed solution was diluted at dilution ratios of 2 times, 5 times, and 10 times;

[0059] The solution density and the concentration of calcium ions of the mixed solutions at different dilution ratios were determined to obtain the content of alkaline calcium.

[0060] In the above test process, the concentration of the two solutions obtained (water washing and acid washing) is mainly tested by the content of calcium ions. However, in the process of engineering practice, the detection of ion concentration is a very time-consuming process. In order to improve the needs of engineering applications, the content of alkaline calcium in the fly ash with a relatively stable composition of the incinerated garbage can be approximately calculated by testing the density of the above two solutions. The specific method is as follows: first, the garbage incineration fly ash is dissolved with the above deionized water or acid solution in a mass ratio of 1:5, and then the obtained solution is filtered, and the solution is diluted with multiple dilution ratios such as 2 times, 5 times, and 10 times, and the solution density is measured, and then a series of equations related to the relationship between solution density and concentration are obtained. According to the equation, the increase in solution density, that is, the concentration of calcium salt dissolved after the acid solution reacts with alkaline calcium, can be calculated by the results measured by the online density detection device.

[0061] It should be noted that at present, the main type of incinerator for waste incineration in my country is the grate furnace. The fly ash produced by the grate furnace is mainly composed of calcium, while the content of silicon oxide and aluminum oxide is usually below 10%. Therefore, in the process of fly ash melting, it is necessary to add additional acidic components such as silicon oxide and aluminum oxide to neutralize the fly ash and promote the melting of the fly ash. Generally speaking, waste glass, slag, aluminum ash, quartz and other materials rich in silicon and aluminum elements are the main additives. In the actual engineering application process, the content ratio of each element in the above additives is relatively stable. Before use, the content of calcium, silicon, aluminum and other elements will be measured to obtain the ratio of fly ash to flux.

[0062] In one embodiment of the present invention, the mixed alkalinity is determined by the following formula:

[0063] HJ=(C Ca-al * M FA * 56 / 40+C Ca-fl * M FL ) / (C Si-fa * M FA +C Al-fa * M FA +C Si-fl * M FL +C Al-fl * M FL )

[0064] In the formula, HJ is the mixed alkalinity, M FA is the first dry basis mass, M FL is the second dry basis mass, C Ca-al is the content of alkaline calcium, CSi-fa is the content of silicon oxide in the first target oxide, C Al-fa is the content of aluminum oxide in the first target oxide, C Ca-fl is the content of calcium oxide in the second target oxide, C Si-fl is the content of silicon oxide in the second target oxide, C Al-fl is the content of aluminum oxide in the second target oxide; wherein the first dry basis mass is the mass after drying and removing moisture from the waste incineration fly ash, and the second dry basis mass is the mass after drying and removing moisture from the flux.

[0065] In one embodiment of the present invention, step S4 may specifically include:

[0066] The mixed alkalinity is controlled between 0.5 and 1.5, and the ratio of the first dry basis mass to the second dry basis mass is calculated;

[0067] The ratio of the first dry basis mass to the second dry basis mass is determined as the ratio of the waste incineration fly ash and the flux.

[0068] Generally speaking, controlling the basicity of fly ash between 0.5-1.5 can ensure that the melting temperature of fly ash is low, and at the same time, the addition ratio of flux is not too much. In the present invention, the fusible calcium-containing components in fly ash are measured by the above technical scheme, and the dynamic ratio of fly ash and flux can be achieved to ensure the stability of the melting temperature of fly ash. By adjusting the ratio of fly ash to flux to change the mixing ratio of the sample after the two are mixed, the basicity of the sample can be controlled within the required range.

[0069] It should be noted that, in the present invention, 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.

[0070] Finally, it should be noted that the above is only a preferred embodiment of the present invention, which is only used to illustrate the technical solution of the present invention, and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A material proportioning method suitable for heat treatment of waste incineration fly ash, characterized in that: include: Determine the contents of basic calcium and a first target oxide in the waste incineration fly ash to be proportioned, and obtain a first determination result; wherein the basic calcium includes calcium oxide, calcium carbonate and calcium hydroxide, and the first target oxide includes aluminum oxide and silicon oxide; Determine the content of the second target oxide in the flux to be proportioned to obtain a second determination result; wherein the second target oxide includes calcium oxide, aluminum oxide and silicon oxide; determining a mixed alkalinity based on the first measurement result and the second measurement result; Based on the mixed alkalinity, the ratio of the waste incineration fly ash and the flux is determined.

2. The method according to claim 1, characterized in that The content of the basic calcium is determined as follows: Determining the content of a first soluble salt that can be dissolved in deionized water in the waste incineration fly ash; Determining the content of a second soluble salt in the waste incineration fly ash that is soluble in an acid solution; wherein the acid solution includes at least one of hydrochloric acid and nitric acid; The difference between the content of the second soluble salt and the content of the first soluble salt is determined as the content of the basic calcium.

3. The method according to claim 2, characterized in that The content of the first soluble salt is determined by: The dried waste incineration fly ash is mixed with deionized water at 40 to 90° C. in a mass ratio of 1:5 to 1:10; The completely dissolved waste incineration fly ash is filtered and dried in sequence to obtain the mass of undissolved fly ash in water; The content of the first soluble salt is determined based on the mass of the dried waste incineration fly ash and the mass of the undissolved fly ash in the water.

4. The method according to claim 3, characterized in that The content of the second soluble salt is determined by: Mixing the dried waste incineration fly ash with an acid solution at 40 to 90° C. in a mass ratio of 1:5 to 1:10; The completely dissolved waste incineration fly ash is filtered and dried in sequence to obtain the mass of the fly ash not dissolved in the acid; The content of the second soluble salt is determined based on the mass of the dried waste incineration fly ash and the mass of the undissolved fly ash in the acid.

5. The method according to claim 2, characterized in that: The content of the first soluble salt is determined by: The dried waste incineration fly ash is mixed with deionized water at 40-90° C. in a mass ratio of 1:20, 1:15, 1:10, and 1:5 respectively; The turbidity of the first solution after mixing at each mass ratio is tested respectively, and the obtained turbidity is converted into the mass of fly ash added in the water; The four obtained turbidities and the mass of fly ash added to the water are plotted into a first standard curve; determining the mass of undissolved fly ash in water based on the first standard curve; The content of the first soluble salt is determined based on the mass of the dried waste incineration fly ash and the mass of the undissolved fly ash in the water.

6. The method according to claim 5, characterized in that The content of the second soluble salt is determined by: The dried waste incineration fly ash is mixed with an acid solution at 40 to 90° C. in a mass ratio of 1:20, 1:15, 1:10, and 1:5, respectively; The turbidity of the second solution after mixing at each mass ratio is tested respectively, and the obtained turbidity is converted into the mass of fly ash added to the acid; The obtained four turbidities and the mass of fly ash added in the acid are plotted into a second standard curve; determining the mass of undissolved fly ash in the acid based on the second standard curve; The content of the second soluble salt is determined based on the mass of the dried waste incineration fly ash and the mass of the undissolved fly ash in the acid.

7. The method according to claim 4, characterized in that The content of alkaline calcium is determined by the following formula: C Ca-al =(M H +M fa -M ud-H )*C Ca-H / M fa -(M w +M fa -M ud-w )*C Ca-w / M fa In the formula, C Ca-al is the content of the alkaline calcium, M H is the mass of the acid solution, M fa is the mass of the undried waste incineration fly ash, M ud-H is the mass of undissolved fly ash in the acid, C Ca-H is the concentration of calcium ions in the acid, M w is the mass of the deionized water, M ud-w is the mass of undissolved fly ash in the water, C Ca-w is the concentration of calcium ions in water.

8. The method according to claim 1, characterized in that The content of the basic calcium is determined as follows: The dried waste incineration fly ash is mixed with deionized water at 40 to 90° C. and an acid solution at a mass ratio of 1:5; The obtained mixed solution was filtered, and the mixed solution was diluted at dilution ratios of 2 times, 5 times, and 10 times; The solution density and the concentration of calcium ions of the mixed solution at different dilution ratios are determined to obtain the content of the alkaline calcium.

9. The method according to any one of claims 1 to 8, characterized in that The mixed alkalinity is determined by the following formula: HJ=(C Ca-al * M FA * 56 / 40+C Ca-fl * M FL ) / (C Si-fa * M FA +C Al-fa * M FA +C Si-fl * M FL +C Al-fl * M FL ) Wherein, HJ is the mixed alkalinity, M FA is the first dry basis mass, M FL is the second dry basis mass, C Ca-al is the content of alkaline calcium, C Si-fa is the content of silicon oxide in the first target oxide, C Al-fa is the content of aluminum oxide in the first target oxide, C Ca-fl is the content of calcium oxide in the second target oxide, C Si-fl is the content of silicon oxide in the second target oxide, C Al-fl is the content of aluminum oxide in the second target oxide; wherein the first dry basis mass is the mass after drying and removing the moisture in the waste incineration fly ash, and the second dry basis mass is the mass after drying and removing the moisture in the flux.

10. The method according to claim 9, characterized in that The method of determining the ratio of the waste incineration fly ash and the flux based on the mixed alkalinity comprises: The mixed basicity is controlled between 0.5 and 1.5, and the ratio of the first dry basis mass to the second dry basis mass is calculated; The ratio of the first dry basis mass to the second dry basis mass is determined as the ratio of the waste incineration fly ash to the flux.

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