Method for treating desulfurized fly ash in semi-dry sintering flue gas desulfurization process

Abstract

The invention provides a method for treating desulfurized fly ash of a semi-dry sintering flue gas desulfurization process, which comprises the following steps of: uniformly premixing the desulfurized fly ash of the semi-dry sintering flue gas desulfurization process with dolomite powder, and adding the mixture into uniformly mixed ore for secondary mixing, so that the desulfurized fly ash is more uniformly mixed in the sintering process, and the desulfurized fly ash and the dolomite powder are mutually wrapped; pelletizing and mixing are uniform after sintering, meanwhile, the situation that desulfurized fly ash is pumped away in the follow-up sintering process is avoided, the amount of flux in a material layer, namely the amount of a liquid phase, cannot be reduced, and the strength of sintered ore is guaranteed. The method can consume the desulfurized fly ash of a semi-dry sintering flue gas desulfurization process, utilizes the high-calcium characteristic of the desulfurized fly ash, exerts the effect of replacing a flux of the desulfurized fly ash, reduces flux consumption, stabilizes the sintering process, can obtain qualified sinter with chemical components meeting requirements after sintering, meets the production requirements of a blast furnace, protects the environment, saves resources, and is suitable for industrial production. And the economic burden of an enterprise is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical manufacturing and relates to a method for treating desulfurized ash. Background Art

[0002] Desulfurization ash is the solid waste produced by semi-dry and dry flue gas desulfurization, while sintering flue gas desulfurization ash is a particle mixture produced after the sintering flue gas reacts with the desulfurizer and is separated by a cyclone separator or a bag dust collector.

[0003] Sintering flue gas desulfurization process is divided into dry method, semi-dry method and wet method. Dry desulfurization efficiency is low, wet method has corrosion and aerosol, semi-dry method better avoids the problems of dry method and wet method, and has the advantages of export flue gas meeting emission standards and no corrosion to equipment pipelines. Since the semi-dry sintering flue gas desulfurization process has the advantages of low investment, small footprint, less water consumption, less corrosion to equipment, dry by-products, no wastewater generation, and simple process, it can well overcome some problems and shortcomings of wet desulfurization process. Semi-dry sintering flue gas desulfurization process has gradually become the leading direction of sintering flue gas desulfurization. With the promotion of semi-dry sintering flue gas desulfurization process, the by-product desulfurization ash produced by it is difficult to use. The treatment of desulfurization ash of semi-dry sintering flue gas desulfurization process still mainly relies on stockpiling, which not only occupies land resources, but also causes secondary pollution to the environment. Management costs and processing costs also increase the economic burden of enterprises. The comprehensive utilization of desulfurization ash has gradually become the main obstacle to the development of semi-dry sintering flue gas desulfurization process. The desulfurization ash of the semi-dry sintering flue gas desulfurization process is unstable in nature and contains a large amount of calcium sulfite (CaSO3·0.5H2O). It has the characteristics of high calcium, fine particle size, strong hydrophilicity and poor stability. It is difficult to granulate and mix the desulfurization ash directly in the traditional sintering process, and part of the desulfurization ash will be directly absorbed as dust ash during the sintering process, resulting in a lack of flux in the material layer, a reduction in liquid phase, and poor strength of the sintered ore obtained by sintering. Summary of the invention

[0004] In order to solve the problem that the desulfurization ash of the semi-dry sintering flue gas desulfurization process described in the background technology is difficult to granulate and mix directly in the traditional sintering process, and the sintered ore has poor strength, the present invention provides a method for treating the desulfurization ash of the semi-dry sintering flue gas desulfurization process.

[0005] The method of the present invention comprises:

[0006] Step 1: Dry the desulfurized ash and crush it by a crusher to obtain desulfurized ash fine powder;

[0007] Step 2: pre-mix desulfurized ash fine powder and dolomite powder in a mass ratio of (15-20): (80-85) and mix them evenly to obtain an ash powder homogeneous mixture;

[0008] Step 3: Using the ash powder mixture as a batching variety of a mixed ore to prepare a mixed ore, wherein the weight ratio of the ash powder mixture to the mixed ore is 6.6-7.2%;

[0009] Step 4: Calculate the proportion of mixed ore, return ore, fuel and flux according to conventional sintering batching, and form a mixed material;

[0010] Step 5: Send the mixed material into the sintering machine for distribution, ignition and sintering to obtain sintered ore.

[0011] Furthermore, in the step 2, the desulfurized ash fine powder and dolomite powder are fed into a high-power mixer and mixed evenly.

[0012] Furthermore, in the step three, the ash powder mixture is fed into a batching ore trough for building a mixed ore pile, and mixed evenly to obtain a mixed ore.

[0013] Furthermore, in the step three, the mixed ore includes the following components in weight ratios: 5-10% Ka powder, 8-10% A powder, 10-25% MAC powder, 10-25% King powder, 5-10% Super special powder, 5-8% Add powder, 8-15% mixed powder, 1-8% high silica powder, 5-6% IOC6 powder, 5-8% Roy Mountain MB powder, 4-6% homogenized material, 0.1-0.3% iron dust mud, 1-2% undersize powder, and 6.6-7.2% ash powder mixture.

[0014] Furthermore, in step 4, the mixture is composed of the following components in weight ratio: 58-65% of mixed ore, 25-30% of returned ore, 3.4-4% of fuel, and 6.6-8% of solvent.

[0015] Furthermore, the fuel is pulverized coal.

[0016] Furthermore, the solvent is limestone and granular ash, wherein the weight ratio of limestone is 3.6-4.5%, and the weight ratio of granular ash is 3-3.5%.

[0017] Furthermore, in step 4, the mixture is composed of the following components in weight ratio: 62.4% of mixed ore, 27% of returned ore, 3.4% of coal powder, 4.0% of limestone, and 3.2% of granular ash. The mixture composed of this component has a small change rate of all chemical components before and after sintering, and the sintering process is very stable.

[0018] Furthermore, in step 4, the mixture is composed of the following components in weight ratio: 59% of mixed powder, 26% of returned ore, 3.6% of coal powder, 3.45% of limestone, 4.4% of dolomite, and 3.55% of granular ash. The mixture composed of this component has a small change rate of all chemical components before and after sintering, and the sintering process is very stable.

[0019] Furthermore, in the method, the weight ratio of the ash powder mixture to the mixed ore is adjusted according to the concentration of SO2 emissions in the sintering machine.

[0020] Compared with the prior art, the present invention premixes the desulfurization ash and dolomite powder in the semi-dry sintering flue gas desulfurization process, and then adds them into the mixed ore for secondary mixing, so that the desulfurization ash is mixed more evenly during the sintering process, and the desulfurization ash and dolomite powder wrap each other, and are granulated and mixed after sintering. At the same time, it also avoids the situation that the desulfurization ash is pumped away during subsequent sintering, so that the amount of flux in the material layer, that is, the amount of liquid phase, will not be reduced, and the strength of the sintered ore is guaranteed; the present invention can consume the desulfurization ash of the semi-dry sintering flue gas desulfurization process, utilize its high calcium characteristics, give play to the role of the desulfurization ash as a substitute for flux, reduce flux consumption, stabilize the sintering process, and obtain qualified sintered ore with chemical composition meeting the requirements after sintering, meet the needs of blast furnace production, protect the environment and save resources, and reduce the economic burden of the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] The treatment method of desulfurization ash in semi-dry sintering flue gas desulfurization process is as follows: Figure 1 As shown, the specific steps are described as follows.

[0024] Step 1: Dry the desulfurization ash, and then crush it through a crusher to obtain desulfurization ash fine powder.

[0025] The desulfurization ash of the semi-dry sintering flue gas desulfurization process has a high mass fraction of CaO, CaSO3 and CaSO4, which can replace part of the flux in sintering.

[0026] Step 2: pre-batch desulfurized ash fine powder and dolomite powder in a mass ratio of (15-20): (80-85) and mix them thoroughly to obtain an ash powder homogeneous mixture.

[0027] Specifically, the desulfurized ash fine powder and dolomite powder are fed into a powerful mixer and mixed evenly.

[0028] Step 3: Use the ash powder mixture as a batching variety of the mixed ore to prepare the mixed ore, wherein the weight ratio of the ash powder mixture to the mixed ore is 6.6-7.2%.

[0029] Specifically, the ash powder mixture is fed into a batching ore tank for building a mixed ore pile, and mixed evenly to obtain a mixed ore.

[0030] More specifically, the mixed ore includes the following components in weight ratios: 5-10% Ka powder, 8-10% A powder, 10-25% MAC powder, 10-25% King powder, 5-10% Super special powder, 5-8% Add powder, 8-15% mixed powder, 1-8% high silica powder, 5-6% IOC6 powder, 5-8% Roy Mountain MB powder, 4-6% homogenized material, 0.1-0.3% iron dust mud, 1-2% undersize powder, and 6.6-7.2% ash powder homogenate.

[0031] Step 4: Calculate the proportions of mixed ore, return ore, fuel and flux according to conventional sintering batching and compose the mixture.

[0032] Specifically, the mixture is composed of the following components in weight ratio: 58-65% of mixed ore, 25-30% of returned ore, 3.4-4% of fuel, and 6.6-8% of solvent, wherein the fuel is coal powder.

[0033] More specifically, the solvent is limestone and granular ash, wherein the weight ratio of the limestone is 3.6-4.5%, and the weight ratio of the granular ash is 3-3.5%.

[0034] Preferably, the mixture is composed of the following components in weight ratio: 62.4% of mixed ore, 27% of returned ore, 3.4% of coal powder, 4.0% of limestone, and 3.2% of granular ash. The mixture composed of this component has a small change rate of all chemical components before and after sintering, and the sintering process is very stable.

[0035] Preferably, the mixture is composed of the following components in weight ratio: 59% of mixed powder, 26% of returned ore, 3.6% of coal powder, 3.45% of limestone, 4.4% of dolomite, and 3.55% of granular ash. The mixture composed of this component has a small change rate of all chemical components before and after sintering, and the sintering process is very stable.

[0036] In the method, the weight ratio of the ash powder mixture to the mixed ore is adjusted according to the SO2 emission concentration in the sintering machine.

[0037] Example 1

[0038] The desulfurization ash is dried and then crushed by a crusher to obtain desulfurization ash fine powder.

[0039] Desulfurized ash fine powder and dolomite powder are pre-mixed in a mass ratio of 15:85, and sent into a high-power mixer to be fully mixed to obtain an ash powder homogeneous mixture.

[0040] The ash powder mixture is sent into the batching ore trough for mixed ore pile construction and mixed evenly to prepare mixed ore. The composition of the mixed ore is as follows: 5% Ka powder, 9% A powder, 13.8% MAC powder, 20% King powder, 10% Super special powder, 7% Add powder, 8.2% mixed powder, 1.2% high silica powder, 6% IOC6 powder, 7% Roy Mountain MB powder, 5.8% homogenized material, 0.3% iron dust mud, and 6.7% ash powder mixture.

[0041] The proportions of mixed ore, return ore, fuel and flux are calculated according to conventional sintering batching, and the mixed material is composed as follows: mixed ore 62.4%, return ore 27%, coal powder 3.4%, limestone 4.0%, and granular ash 3.2%.

[0042] The mixed material is fed into a sintering machine for distribution, ignition and sintering to obtain sintered ore.

[0043] Example 2

[0044] The desulfurization ash is dried and then crushed by a crusher to obtain desulfurization ash fine powder.

[0045] Desulfurized ash fine powder and dolomite powder are pre-mixed in a mass ratio of 15:85, and sent into a high-power mixer to be fully mixed to obtain an ash powder homogeneous mixture.

[0046] The ash powder mixture is sent into the batching ore trough for mixed ore pile construction and mixed evenly to prepare a mixed ore. The composition of the mixed ore is as follows: 7.7% Ka powder, 8% A powder, 22% MAC powder, 16.1% King powder, 5.5% Jia powder, 14.1% mixed powder, 4.9% high silica powder, 4.2% IOC6 powder, 8% Roy Mountain MB powder, 0.4% iron dust mud, 2% undersize powder, and 7.1% ash powder mixture.

[0047] According to the conventional sintering batching, the proportions of mixed ore, return ore, fuel and flux are calculated to form a mixed material. The composition of the mixed material is as follows: mixed powder 59%, return ore 26%, coal powder 3.6%, limestone 3.45%, dolomite 4.4%, and granular ash 3.55%.

[0048] The mixed material is fed into a sintering machine for distribution, ignition and sintering to obtain sintered ore.

[0049] Example 3

[0050] The desulfurization ash is dried and then crushed by a crusher to obtain desulfurization ash fine powder.

[0051] Desulfurized ash fine powder and dolomite powder are pre-mixed in a mass ratio of 18:82, and fed into a high-power mixer to be fully mixed to obtain an ash powder homogeneous mixture.

[0052] The ash powder mixture is sent into the batching ore trough for mixed ore pile construction and mixed evenly to prepare a mixed ore. The composition of the mixed ore is as follows: Ka powder 6%, A powder 8%, MAC powder 20%, King powder 12%, super special powder 8%, added powder 6%, mixed powder 9%, high silica powder 5%, IOC6 powder 5.5%, Roy Mountain MB powder 6%, homogenized material 5.5%, iron dust mud 0.2%, undersize powder 2%, and ash powder mixture 6.8%.

[0053] The proportions of mixed ore, return ore, fuel and flux are calculated according to conventional sintering batching, and the mixed material is composed as follows: mixed ore 62%, return ore 26%, coal powder 4%, limestone 4.5%, and granular ash 3.5%.

[0054] The mixed material is fed into a sintering machine for distribution, ignition and sintering to obtain sintered ore.

[0055] Example 4

[0056] The desulfurization ash is dried and then crushed by a crusher to obtain desulfurization ash fine powder.

[0057] Desulfurized ash fine powder and dolomite powder are pre-mixed in a mass ratio of 16:84, and sent into a high-power mixer to be fully mixed to obtain an ash powder homogeneous mixture.

[0058] The ash powder mixture is sent into the batching ore trough for mixed ore pile construction and mixed evenly to prepare mixed ore. The composition of the mixed ore is as follows: 8% Ka powder, 8% A powder, 18% MAC powder, 10% King powder, 10% Super special powder, 6% Add powder, 10% mixed powder, 4% high silica powder, 5.5% IOC6 powder, 6% Roy Mountain MB powder, 5.5% homogenized material, 0.3% iron dust mud, 1.5% undersize powder, and 7.2% ash powder mixture.

[0059] According to the conventional sintering batching, the proportion of mixed ore, return ore, fuel and flux is calculated to form a mixed material. The composition of the mixed material is as follows: mixed ore 58%, return ore 30%, coal powder 4%, limestone 4.5%, and granular ash 3.5%.

[0060] The mixed material is fed into a sintering machine for distribution, ignition and sintering to obtain sintered ore.

[0061] Example 5

[0062] The desulfurization ash is dried and then crushed by a crusher to obtain desulfurization ash fine powder.

[0063] Desulfurized ash fine powder and dolomite powder are pre-mixed in a mass ratio of 20:80, and sent into a high-power mixer to be fully mixed to obtain an ash powder homogeneous mixture.

[0064] The ash powder mixture is sent into the batching ore trough for mixed ore pile construction and mixed evenly to prepare a mixed ore. The composition of the mixed ore is as follows: 10% Ka powder, 10% A powder, 20% MAC powder, 10% King powder, 10% Super special powder, 6% Add powder, 10.2% mixed powder, 4.1% high silica powder, 5% IOC6 powder, 6% Roy Mountain MB powder, 0.1% iron dust mud, 2% undersize powder, and 6.6% ash powder mixture.

[0065] The proportions of mixed ore, return ore, fuel and flux are calculated according to conventional sintering batching, and the mixed material is composed as follows: mixed ore 65%, return ore 25%, coal powder 3.4%, limestone 3.6%, and granular ash 3%.

[0066] The mixed material is fed into a sintering machine for distribution, ignition and sintering to obtain sintered ore.

[0067] The components of the mixed ore and the sintered ore of Examples 1-5 were tested respectively, and the results are shown in Table 1. It can be seen that the chemical composition of the sintered ore obtained after sintering of the present invention meets the requirements, and the components meet the needs of blast furnace production.

[0068] Table 1 List of mixed ore composition and sintered ore composition

[0069]

[0070]

[0071] The present invention solves the problems of fine particle size, strong hydrophilicity, unstable properties, difficulty in granulation of desulfurized ash in the semi-dry sintering flue gas desulfurization process, and direct traditional batching during sintering by exhaust air on the sintering machine. A part of the desulfurized ash is directly sucked away as dust removal ash, resulting in lack of flux in the material layer, insufficient CaO, reduced liquid phase, and deterioration of sintered ore strength. The present invention mixes desulfurized ash with dolomite powder, and the mixed ore is mixed again during the pile building process. The dolomite powder, desulfurized ash and other components are fully mixed and wrapped, which can effectively prevent the desulfurized ash from being sucked away during sintering, consume the desulfurized ash, give play to the flux of the desulfurized ash, and stabilize the sintering process. In addition, the proportion of the desulfurized ash in the process can be adjusted according to the SO2 emission concentration of the sintering machine.

[0072] In particular, for the mixed materials of Example 1 and Example 2, the change rates of all chemical components before and after sintering are not large, and the sintering process is very stable.

[0073] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A method for treating desulfurization ash in a semi-dry sintering flue gas desulfurization process, characterized in that: include: Step 1: Dry the desulfurized ash and crush it by a crusher to obtain desulfurized ash fine powder; Step 2: pre-mix desulfurized ash fine powder and dolomite powder in a mass ratio of (15-20): (80-85) and mix them evenly to obtain an ash powder homogeneous mixture; Step 3: Using the ash powder mixture as a batching variety of a mixed ore to prepare a mixed ore, wherein the weight ratio of the ash powder mixture to the mixed ore is 6.6-7.2%; Step 4: Calculate the proportion of mixed ore, return ore, fuel and flux according to conventional sintering batching, and form a mixed material; Step 5: Send the mixed material into the sintering machine for distribution, ignition and sintering to obtain sintered ore.

2. The method for treating desulfurization ash of the semi-dry sintering flue gas desulfurization process according to claim 1 is characterized in that: In the step 2, the desulfurized ash fine powder and dolomite powder are fed into a high-power mixer and mixed evenly.

3. The method for treating desulfurization ash of the semi-dry sintering flue gas desulfurization process according to claim 2 is characterized in that: In the step three, the ash powder mixture is sent into the batching ore tank for mixing ore and mixed evenly to obtain the mixed ore.

4. The method for treating desulfurization ash of the semi-dry sintering flue gas desulfurization process according to claim 3 is characterized in that: In the step 3, the mixed ore includes the following components in weight ratio: 5-10% Ka powder, 8-10% A powder, 10-25% MAC powder, 10-25% King powder, 5-10% Super special powder, 5-8% Add powder, 8-15% mixed powder, 1-8% high silica powder, 5-6% IOC6 powder, 5-8% Roy Mountain MB powder, 4-6% homogenized material, 0.1-0.3% iron dust mud, 1-2% undersize powder, and 6.6-7.2% ash powder mixture.

5. The method for treating desulfurization ash of the semi-dry sintering flue gas desulfurization process according to claim 4 is characterized in that: In step 4, the mixture is composed of the following components in weight ratio: 58-65% of mixed ore, 25-30% of returned ore, 3.4-4% of fuel, and 6.6-8% of solvent.

6. The method for treating desulfurization ash of the semi-dry sintering flue gas desulfurization process according to claim 5 is characterized in that: The fuel is pulverized coal.

7. The method for treating desulfurization ash of the semi-dry sintering flue gas desulfurization process according to claim 6 is characterized in that: The solvent is limestone and granular ash, wherein the weight ratio of the limestone is 3.6-4.5%, and the weight ratio of the granular ash is 3-3.5%.

8. The method for treating desulfurization ash of the semi-dry sintering flue gas desulfurization process according to claim 7 is characterized in that: In the step 4, the mixture is composed of the following components in weight ratio: 62.4% of mixed ore, 27% of returned ore, 3.4% of coal powder, 4.0% of limestone, and 3.2% of granular ash.

9. The method for treating desulfurization ash of the semi-dry sintering flue gas desulfurization process according to claim 7, characterized in that: In the step 4, the mixture is composed of the following components in weight ratio: 59% of mixed powder, 26% of returned ore, 3.6% of coal powder, 3.45% of limestone, 4.4% of dolomite, and 3.55% of granular ash.

10. The method for treating desulfurized ash in a semi-dry sintering flue gas desulfurization process according to any one of claims 1 to 9, characterized in that: In the method, the weight ratio of the ash powder mixture to the mixed ore is adjusted according to the concentration of SO2 emission in the sintering machine.

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