A material proportioning method suitable for waste incineration fly ash heat treatment

Abstract

The present application relates to the technical field of waste incineration fly ash heat treatment, and particularly relates to a material proportioning method suitable for waste incineration fly ash heat treatment. The technical scheme respectively determines the content of alkaline 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 fluxing agent to be proportioned, obtains the first determination result and the second determination result, then determines the mixed alkalinity based on the first determination result and the second determination result, and finally determines the proportion of the waste incineration fly ash and the fluxing agent based on the mixed alkalinity. Therefore, the above technical scheme can reasonably calculate the mixing proportion of the waste incineration fly ash and the fluxing agent, so as to realize the stability of the fly ash heat treatment temperature and improve the uniformity of the heat treatment product composition.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste incineration fly ash heat treatment, and particularly relates to a material proportioning method suitable for waste incineration fly ash heat treatment. BACKGROUND

[0002] High-temperature heat treatment technology can efficiently realize 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 the waste incineration fly ash often determines the melting temperature of the material.

[0003] However, since the waste incineration fly ash contains a large amount of chlorides (such as sodium chloride, potassium chloride, calcium chloride, etc.), this will cause a large deviation between the measured proportion of oxides of silicon, aluminum and calcium (i.e. calcium oxide, aluminum oxide and silicon oxide) and the actual melting product. In addition, the content of calcium element in the waste incineration fly ash is affected by the amount of lime slurry sprayed in the semi-dry method deacidification. Over-spraying of the lime slurry will cause the content of basic calcium (i.e. calcium oxide, calcium hydroxide and calcium carbonate) in the fly ash to increase. When the concentration of acidic gas in the flue gas is relatively high, the reaction of the lime slurry with the acidic gas is relatively complete, the content of basic calcium-containing substances in the lime slurry decreases, and the content of calcium chloride and other calcium salts significantly increases. However, these calcium salts will not react with other oxides in the fly ash to form a molten phase at high temperatures. Therefore, the content of basic calcium in the waste incineration fly ash will directly affect the formation of the ternary oxide system of silicon, aluminum and calcium during high-temperature heat treatment.

[0004] In related technologies, 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-base oxides therein, so as to ensure that the fly ash can be melted at a relatively low temperature and the system can be stably operated. Therefore, before the waste incineration fly ash is subjected to heat treatment, the content of the oxide components actually participating in the melting in the fly ash is determined, and the mixing ratio of the fly ash and the flux is reasonably calculated, so as to realize the stability of the fly ash heat treatment temperature and improve the uniformity of the heat treatment product composition. SUMMARY

[0005] The present application provides a material proportioning method suitable for waste incineration fly ash heat treatment, which can reasonably calculate the mixing ratio of waste incineration fly ash and flux, so as to realize the stability of the fly ash heat treatment temperature and improve the uniformity of the heat treatment product composition.

[0006] The present application provides a material proportioning method suitable for waste incineration fly ash heat treatment, which can reasonably calculate the mixing ratio of waste incineration fly ash and flux, so as to realize the stability of the fly ash heat treatment temperature and improve the uniformity of the heat treatment product composition.

[0007] The content of basic calcium and a first target oxide in the waste incineration fly ash to be proportioned is determined to 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] determining a content of the second target oxide in the flux to be proportioned to obtain a second determination result; wherein the second target oxide comprises calcium oxide, aluminum oxide and silicon oxide;

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

[0010] determining the proportioning of the waste incineration fly ash and the flux based on the mixed alkalinity.

[0011] From the above scheme, the material proportioning method suitable for waste incineration fly ash heat treatment provided by the present application is provided. The content of the alkaline 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 determined respectively to obtain the first determination result and the second determination result. Then, the mixed alkalinity is determined based on the first determination result and the second determination result. Finally, the proportioning of the waste incineration fly ash and the flux is determined based on the mixed alkalinity. Therefore, the above technical scheme can reasonably calculate the mixing proportion of the waste incineration fly ash and the flux to realize the stability of the fly ash heat treatment temperature and improve the uniformity of the heat treatment product composition. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative labor.

[0013] Figure 1 The flowchart of the material proportioning method suitable for waste incineration fly ash heat treatment provided by the present application is shown. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0015] Please refer to Figure 1 An embodiment of the present application provides a material proportioning method suitable for waste incineration fly ash heat treatment, which comprises:

[0016] Step S1, the content of the basic calcium and the first target oxide in the waste incineration fly ash to be proportioned is determined to 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;

[0017] Step S2, the content of the second target oxide in the fluxing agent to be proportioned is determined to obtain a second determination result; wherein the second target oxide includes calcium oxide, aluminum oxide and silicon oxide;

[0018] Step S3, the mixed basicity is determined based on the first determination result and the second determination result;

[0019] Step S4, the proportioning of the waste incineration fly ash and the fluxing agent is determined based on the mixed basicity.

[0020] In the embodiment, the content of the 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 fluxing agent to be proportioned are determined respectively to obtain the first determination result and the second determination result, then the mixed basicity is determined based on the first determination result and the second determination result, and finally the proportioning of the waste incineration fly ash and the fluxing agent is determined based on the mixed basicity. Therefore, the above technical solution can reasonably calculate the mixing ratio of the waste incineration fly ash and the fluxing agent to realize the stability of the fly ash heat treatment temperature and improve the uniformity of the heat treatment product composition.

[0021] That is, the above technical solution detects the content of the calcium-containing component actually participating in the melting reaction in the waste incineration fly ash, and then guides the proportioning before the high-temperature heat treatment of the fly ash, solves the problem of the difference between the proportioning composition and the actual fly ash composition after melting in the traditional detection method, and avoids the fly ash melting temperature fluctuation caused by inaccurate addition of the fluxing agent.

[0022] In some embodiments, the content of the first target oxide and the second target oxide is determined by an XRF spectrometer.

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

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

[0025] The content of the second soluble salt that can be dissolved in an acid solution in the waste incineration fly ash is determined; 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 first soluble salt is determined as the content of the basic calcium.

[0027] In the present embodiment, considering that the basic calcium mainly includes calcium oxide, calcium carbonate and calcium hydroxide, the basic 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 the basic calcium.

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

[0029] The dried waste incineration fly ash is mixed with deionized water at a temperature of 40-90°C at a mass ratio of 1:5-1:10;

[0030] After complete dissolution, the waste incineration fly ash is sequentially filtered and dried to obtain the mass of the fly ash not dissolved in water;

[0031] Based on the mass of the dried waste incineration fly ash and the fly ash not dissolved in water, the content of the first soluble salt is determined.

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

[0033] Considering that the fly ash will continuously absorb water during storage, resulting in continuous increase in its mass, however, the water in the fly ash is completely removed during high-temperature heat treatment. Therefore, removing the water absorbed by the fly ash during storage and the crystal water can obtain a weight reference closer to the high-temperature heat treatment state of the fly ash, which helps to improve the accuracy of the fly ash ratio. The fly ash drying process needs to be heated at 400-500°C for 1-4 hours to obtain a dried fly ash sample, and the water content of the fly ash is calculated according to the difference before and after drying.

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

[0035] The dried waste incineration fly ash is mixed with an acid solution at a temperature of 40-90°C at a mass ratio of 1:5-1:10;

[0036] After complete dissolution, the waste incineration fly ash is sequentially filtered and dried to obtain the mass of the fly ash not dissolved in acid;

[0037] Based on the mass of the dried waste incineration fly ash and the fly ash not dissolved in acid, the content of the second soluble salt is determined.

[0038] In the present 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, and at the same time, the basic calcium in the dried waste incineration fly ash can be more fully dissolved into the acid solution at this temperature.

[0039] In some embodiments, the calcium content in fly ash is generally about 20-40%, so when configuring the acid solution, it is necessary to ensure that the hydrogen ions are absolutely excessive, so as to ensure that the basic calcium is completely dissolved into the acid solution. According to the dissolution characteristics of the acid solution, hydrochloric acid and nitric acid are preferred in the present application. In addition, in order to increase the solubility of calcium sulfate in fly ash, ammonium chloride can be added to the acid solution, and the addition amount is 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 0.2-1% by volume.

[0040] In an embodiment of the present application, the content of the first soluble salt is determined by the following method:

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

[0042] The turbidity of each first solution mixed at different mass ratios is tested, and the obtained turbidity is converted into the mass of fly ash added in water;

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

[0044] Based on the first standard curve, the mass of undissolved fly ash in water is determined;

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

[0046] In an embodiment of the present application, the content of the second soluble salt is determined by the following method:

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

[0048] The turbidity of each second solution mixed at different mass ratios is tested, and the obtained turbidity is converted into the mass of fly ash added in the acid;

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

[0050] Based on the second standard curve, the mass of undissolved fly ash in the acid is determined;

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

[0052] In an embodiment of the present application, the content of the 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 basic calcium, M H is the mass of the acid solution, M fa is the mass of the non-dried waste incineration fly ash, M ud-H is the mass of the non-dissolved 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 the non-dissolved fly ash in the water, C Ca-w is the concentration of calcium ions in the water.

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

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

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

[0058] The obtained mixed solution is filtered and diluted at a dilution ratio of 2 times, 5 times and 10 times, respectively.

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

[0060] During the above test process, the concentrations of the two solutions (water washing, acid washing) are mainly tested by testing the content of calcium ions. However, during the engineering practice, the detection of ion concentration is a very time-consuming process. In order to improve the need of engineering application, the content of alkaline calcium in fly ash with relatively stable composition of 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 at a mass ratio of 1:5, then the obtained solution is filtered, and the solution is diluted at multiple dilution ratios such as 2 times, 5 times, 10 times, and the solution density is measured, and then a series of solution density and concentration relationship equations are obtained. According to the equation, the solution density increase can be calculated by the result measured by the online density detection device, that is, the concentration of calcium salt dissolved after the reaction of the acid solution with the alkaline calcium.

[0061] It should be noted that at present, the grate furnace is the main incineration furnace type in garbage incineration in China, and the fly ash generated by the grate furnace incineration is mainly composed of calcium elements, and the content of silicon oxide and aluminum oxide is usually less than 10%, so additional acidic components such as silicon oxide and aluminum oxide need to be added to neutralize the fly ash during the fly ash melting process, thereby promoting 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 actual engineering application, the content ratio of each element in the above additives is relatively stable, and before use, the content of calcium, silicon, aluminum and other elements in the above additives is measured, and then the ratio of fly ash and fluxing agent is obtained.

[0062] In an embodiment of the present application, 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 C is a content of silicon oxide in the first target oxide Al-fa C is a content of aluminum oxide in the first target oxide Ca-fl C is a content of calcium oxide in the second target oxide Si-fl C is a content of silicon oxide in the second target oxide Al-fl C is a content of aluminum oxide in the second target oxide; wherein the first dry basis mass is a mass after drying to remove water in the municipal solid waste incineration fly ash, and the second dry basis mass is a mass after drying to remove water in the fluxing agent.

[0065] In an embodiment of the present application, the step S4 can specifically include:

[0066] controlling the mixed alkalinity to be between 0.5 and 1.5, and calculating the ratio of the first dry basis mass and the second dry basis mass;

[0067] determining the ratio of the first dry basis mass and the second dry basis mass as the ratio of the municipal solid waste incineration fly ash and the fluxing agent.

[0068] Generally, controlling the alkalinity of the fly ash to be between 0.5 and 1.5 can ensure that the fly ash melting temperature is relatively low, and meanwhile the addition ratio of the fluxing agent is not too high. In the present application, by measuring the meltable calcium-containing components in the fly ash through the above technical solution, dynamic ratio of the fly ash and the fluxing agent can be realized, and the stability of the fly ash melting temperature can be ensured. By adjusting the ratio of the fly ash and the fluxing agent to change the mixing ratio of the sample after mixing, the alkalinity of the sample can be controlled in the required range.

[0069] It should be noted that, in the present application, the relationship 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 the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0070] Finally, it should be noted that: the above description is only the preferred embodiment of the present application, which is only used to illustrate the technical scheme of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A material proportioning method suitable for heat treatment of waste incineration fly ash, characterized in that: include: The contents of basic calcium and a first target oxide in the waste incineration fly ash to be proportioned are measured to obtain 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; Measuring the content of a 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; determining a mixed alkalinity based on the first measurement result and the second measurement result; Determining a ratio of the waste incineration fly ash and the flux based on the mixed alkalinity; The content of the basic calcium is determined as follows: Determining the content of a first soluble salt soluble 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 comprises 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.

2. The method according to claim 1, characterized in that The content of the first soluble salt is determined by: Mixing the dried waste incineration fly ash with deionized water at 40-90° C. in a mass ratio of 1:5-1:10; 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.

3. The method according to claim 2, characterized in that The content of the second soluble salt is determined as follows: Mixing the dried waste incineration fly ash with an acid solution at 40-90° C. in a mass ratio of 1:5-1:10; 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.

4. The method according to claim 1, wherein The content of the first soluble salt is determined by: The dried waste incineration fly ash was 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 to 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.

5. The method according to claim 4, characterized in that The content of the second soluble salt is determined as follows: The dried waste incineration fly ash was mixed with an acid solution at a temperature of 40-90° C. at 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 four obtained turbidities and the mass of fly ash added to 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.

6. The method according to claim 3, characterized in that The content of the basic 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 Where C Ca-al is the content of the basic 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.

7. The method according to any one of claims 1 to 6, 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 the 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 moisture from the waste incineration fly ash, and the second dry basis mass is the mass after drying and removing moisture from the flux.

8. The method according to claim 7, characterized in that The step of determining the ratio of the waste incineration fly ash and the flux based on the mixed alkalinity includes: Controlling the mixed alkalinity between 0.5 and 1.5, and calculating the ratio of the first dry basis mass to the second dry basis mass; 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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