Method for preparing ceramsite and enriching sulfur oxide gas from sulfur-containing solid waste

Abstract

The invention provides a method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste, and relates to the technical field of ceramic product firing, and the method comprises the following steps: mixing the sulfur-containing solid waste with auxiliary materials to prepare ceramsite green pellets, the mass percentage content of sulfur element in the ceramsite green pellets is more than 5%, the mass percentage content of calcium oxide is 5.16-22.11%, and the mass percentage content of sulfur oxide in the ceramsite green pellets is 0.12-0.12%; the mass percentage content of silicon oxide is 38.97 to 59.21 percent; the ceramsite green pellets are conveyed into a roasting furnace to be roasted, sulfur dioxide is released in a high-temperature roasting section or a low-temperature roasting section in a heat preservation mode, flue gas is enriched through flue gas circulation, sulfur dioxide is collected, and sintered ceramsite is obtained. In the ceramsite preparation process, the sulfur oxide gas is released, the flue gas is circularly enriched, and the sulfur oxide is recycled, so that the efficient utilization of all components is realized, the decomposition of sulfate can be promoted, the sulfur oxide release reaction temperature is reduced, and the energy consumption is reduced by utilizing the high-temperature calcium-containing silicate reaction process of the ceramsite. The whole system is low in comprehensive energy consumption, balanced in temperature control and environment-friendly.

Description

Technical Field

[0001] The invention relates to the technical field of ceramic product firing, and in particular to a method for preparing ceramsite and enriching sulfur oxide gas by utilizing sulfur-containing solid waste. Background Art

[0002] Dust solid waste and industrial by-product sulfur-containing solid waste discharged from steel mills refer to solid waste containing one or more of sulfate, sulfite or sulfide, including industrial by-product desulfurization gypsum, industrial by-product desulfurization ash, electrolytic manganese slag, high-sulfur coal gangue, high-sulfur tailings, high-sulfur waste slag and sulfur-containing sludge. The mass percentage of sulfur in these sulfur-containing solid wastes exceeds 3%. There is little research on the utilization of sulfide-containing solid wastes, which are usually burned into ceramsite by rotary kiln or sintering machine process for resource utilization.

[0003] A rotary kiln is used to fire expanded clay, and sulfur-containing solid waste is used to prepare expanded clay balls. The expanded clay balls are then sent to a roasting furnace for roasting. The roasting process can efficiently prepare expanded clay according to a certain heating system. It is environmentally friendly and has adjustable temperature. However, the sulfur oxide gas generated during the roasting of solid waste with a high sulfur content needs to be recovered and treated. However, in the expanded clay firing process, the flue gas emitted during the sintering process of the raw balls is not further treated for sulfur oxide recovery.

[0004] In addition, heating is carried out from the kiln head and hot air is discharged from the kiln tail. The determination of the roasting section of the whole process is not determined by the reaction mechanism of the sulfur-containing elements in the expanded clay releasing sulfur oxides. In the rotary kiln process, if the components containing higher sulfur cannot be completely decomposed and released during the firing process, alkali efflorescence will appear on the surface of the final expanded clay product and the sulfur content will exceed the standard value by 1%. Summary of the invention

[0005] The present invention provides a method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste, so as to solve the technical problems that sulfur cannot be completely decomposed and released during the firing process of the existing solid waste raw materials with high sulfur content, and the surface of the prepared ceramsite finished product is prone to efflorescence and the sulfur content is too high.

[0006] In order to achieve the above-mentioned invention object, the technical solution provided by the present invention is as follows:

[0007] A method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste comprises the following steps:

[0008] S1. Mixing the sulfur-containing solid waste with auxiliary materials to prepare ceramsite green balls, wherein the raw materials of the ceramsite green balls include 40-65 parts of the sulfur-containing solid waste and 35-60 parts of the auxiliary materials by weight, and the weight percentage of sulfur in the ceramsite green balls exceeds 5%, the weight percentage of calcium oxide is 5.16-22.11%, and the weight percentage of silicon oxide is 38.97-59.21%;

[0009] S2, sending the ceramsite green balls to a roasting furnace for roasting, maintaining high temperature to release sulfur dioxide, enriching and collecting sulfur dioxide, and obtaining sintered ceramsite.

[0010] Preferably, the sulfur-containing solid waste in S1 is solid waste containing one or more of sulfate, sulfite and sulfide.

[0011] Preferably, the sulfur-containing solid waste in S1 contains sulfide, and the temperature of the high-temperature insulation is 400-600°C.

[0012] Preferably, the sulfur-containing solid waste in S1 contains sulfite or sulfate, and the temperature of the high-temperature insulation is 950-1180°C.

[0013] Preferably, the sulfur-containing solid waste in S1 contains sulfide and sulfate, and the high-temperature insulation is performed at 400-600° C. and 950-1180° C. in sequence.

[0014] Preferably, the sulfur-containing solid waste in S1 is one or more of rotary kiln waste slag, pyrite slag, desulfurized gypsum, industrial by-product desulfurized gypsum, sulfur-containing waste slag, and high-sulfur tailings.

[0015] Preferably, the auxiliary material in S1 is one or more of shale, clay, slag, fly ash, dredged mud, and desulfurized gypsum.

[0016] Preferably, the size of the ceramsite raw balls in S1 is 9-15 mm.

[0017] Preferably, the sulfur dioxide in S2 is used to prepare sulfuric acid or sulfate.

[0018] Preferably, the mass percentage of sulfur in the sintered ceramsite is less than 2%, and the mineral phase is one or more of anorthite, hematite, quartz, orthoclase, and pyroxene.

[0019] The calcium oxide and silicon oxide contents in the ceramsite green balls are within the scope of the present invention, which can ensure the formation of mesoprolite and anorthite phases in the sample after calcining the ceramsite, thereby enhancing the strength of the ceramsite.

[0020] The method proposed in the present invention releases sulfur dioxide by roasting sulfur-containing solid waste containing a large amount of sulfide, and realizes the enrichment of sulfur dioxide and the sintering of ceramsite. The present invention also points out the appropriate temperature range for sulfide to release sulfur dioxide. When the sulfur-containing solid waste contains sulfide, it is necessary to keep it warm at 350-550°C to release sulfur dioxide; when the sulfur-containing solid waste contains sulfide and the mass percentage of calcium oxide is 9-22%, it is necessary to keep it warm at 350-550°C and 950-1150°C at the same time to ensure the release of sulfur dioxide; when the sulfur-containing solid waste contains sulfite or sulfate, it is necessary to keep it warm at 950-1180°C to release sulfur dioxide. When the sulfur-containing solid waste contains both sulfide and sulfate, it is necessary to keep it warm at 350-550°C and 950-1180°C at the same time to ensure the release of sulfur dioxide. Ensure that the desulfurization reaction is fully carried out during the roasting process, avoid the low desulfurization rate in the process of preparing ceramsite from high-sulfur solid waste, and the high sulfur content and alkali phenomenon in the final product. The desulfurized ceramsite has good performance and improves the utilization rate of high-sulfur raw materials. The complete release of sulfur dioxide can be guaranteed within the corresponding temperature range.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] While preparing silicate product ceramsite, the present invention can also roast and release a large amount of sulfur-containing solid waste of sulfide, and points out the temperature range for the sulfide to release sulfur dioxide. While discovering that these different sulfides have different sulfur oxide release ranges, the inventors realized that the current roasting process of ceramsite can adopt an exhaust roasting method, and this method can be used to circulate and enrich the flue gas for utilization. This patent proposes to circulate the flue gas in combination with the release temperature range of sulfur dioxide, which can increase the concentration of sulfur oxide in the flue gas, reduce the amount of flue gas, and improve the recovery and utilization efficiency of sulfur oxide flue gas.

[0023] The present invention proposes to release sulfur oxide gas and recycle it during the preparation process of expanded clay, which not only realizes efficient utilization of all components and improves economic benefits, but also utilizes the high-temperature calcium silicate reaction process of expanded clay to promote the decomposition of sulfate and reduce the sulfur oxide release reaction temperature, so that the overall energy consumption of the entire system is low, the temperature control is balanced, and it is green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The sulfur content of sulfur-containing iron ore slag ceramsite changes at different temperatures;

[0025] Figure 2 The XRD patterns of ceramsite prepared from pyrite slag at different temperatures;

[0026] Figure 3 Another XRD pattern of ceramsite prepared from pyrite slag at different temperatures;

[0027] Figure 4 The XRD patterns of ceramsite containing gypsum solid waste at different sintering temperatures;

[0028] Figure 5 A gas circulation process flow chart of a method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste provided in a specific embodiment;

[0029] Figure 6 Another gas circulation process flow chart involved in a method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste provided in a specific embodiment;

[0030] Figure 7 Another gas circulation process flow chart involved in a method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste provided in a specific embodiment;

[0031] Figure 8 Another gas circulation process flow chart involved in a method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste provided in a specific embodiment. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The sulfur content of pyrite slag ceramsite was measured at different temperatures. The results are as follows: Figure 1 It can be seen that there are two significant desulfurization stages in the temperature ranges of 400-600℃ and 950-1180℃.

[0034] XRD patterns of ceramsite prepared from pyrite slag at different temperatures. Figure 2 and Figure 3 It can be seen that the pyrite-containing ceramsite still has pyrite at 485℃, but the transformation disappears after 600℃, and the corresponding hematite and gypsum ore phases appear, which indicates that the pyrite is oxidized in large quantities at this stage, part of the sulfur is converted into sulfur oxide and released, and the iron is converted into hematite, which corresponds to the first desulfurization stage; part of the sulfur is solidified by the calcium oxide in the ceramsite to form gypsum. At 600-1000℃, the peak of gypsum increases significantly, indicating that the solid sulfur reaction is enhanced at this stage; at 1000-1160℃, the gypsum peak disappears again, indicating that gypsum is decomposed, which also corresponds to the high-temperature desulfurization stage.

[0035] XRD patterns of ceramsite containing gypsum solid waste at different sintering temperatures, such as Figure 4 It can be seen that the diffraction peak of gypsum does not decrease significantly until 1100℃, and basically disappears at 1160℃, indicating that the decomposition reaction of gypsum occurs at 1100-1160℃.

[0036] Example 1

[0037] The present embodiment provides a method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste, wherein the sulfur-containing solid waste rotary kiln waste residue is used as the main raw material, and the rotary kiln waste residue contains pyrite and zinc sulfide as the main sulfur-containing mineral phases, and the mass ratio of the rotary kiln waste residue to the auxiliary material is 60:40, and the auxiliary materials are fly ash, dredging mud and clay. The ground powder is used for granulation by an extrusion granulator or a disc granulator, the diameter of the ceramsite green ball is 9mm, the average single ball compressive strength is 148N, the sulfur oxide content in the ceramsite green ball is 7.34wt%, the calcium oxide content is 22.11wt%, and the silicon oxide content is 38.97wt%. The ceramsite is sent to a roasting furnace for firing, and the average cylinder compressive strength of the ceramsite after firing is 8.5MPa, and the water absorption rate is 9.6%, which meets the requirements of the national standard for light aggregate (GB / T17431.1-2010), and the cylinder compressive strength shall not be less than 5.0MPa. The roasting furnace refers to the ceramsite roasting machine, the highest roasting temperature is 1250℃, including drying section 1, drying section 2, ignition section, low temperature desulfurization section 550℃, high temperature desulfurization section 1050℃, roasting section 1160℃, soaking section 1100℃, cooling section 1, cooling section 2. The gas circulation process flow chart is as follows: Figure 5 The high-temperature desulfurization section discharges 550℃ flue gas and the roasting and soaking section discharges high-temperature flue gas. The ceramsite that circulates to the low-temperature desulfurization section is heated and enriched with sulfur oxide before discharging flue gas, further realizing the resource utilization of flue gas containing sulfur dioxide; the remaining exhaust gas from the roasting and soaking section can be heated in the drying section 2 or output waste heat, and then treated and discharged as ordinary flue gas. The sulfur content of the final finished ceramsite is 0.95%, and the main mineral phases are calcium feldspar, hematite, and quartz. The sulfur content of ceramsite does not exceed 1%, which meets the detection content of sulfide and sulfate of ceramsite and is lower than the concentration limit of 1% in GB / T17431.2-201017 "Light Aggregate and Its Test Method Part 1: Light Aggregate".

[0038] Example 2

[0039] The present embodiment provides a method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste, wherein sulfur-containing iron ore slag and desulfurized gypsum are used together as sulfur-containing solid waste to prepare ceramsite, and auxiliary materials are shale, clay and clay. The mass ratio of sulfur-containing solid waste to auxiliary materials is 70:30, and the sulfur content of ceramsite raw balls is 9.5wt%, the calcium oxide content is 16wt%, and the silicon oxide content is 48wt%. The ceramsite is sent to a roasting furnace for firing. In this case, the kiln for calcining ceramsite is divided into drying section 1, drying section 2, ignition section, low-temperature desulfurization section 500℃, preheating section 700℃, roasting high-temperature desulfurization section 1120℃, equalizing section 1100℃, cooling section 1 and cooling section 2. The gas circulation process flow chart of ceramsite raw balls with higher calorific value (calorific value is 380kcal / kg) is as follows Figure 6 That is, the hot air with high oxygen content or the mixed gas with cooling air is first discharged into the low-temperature desulfurization section and the preheating section, and the 700℃ flue gas discharged is recycled to the ceramsite heating section of the roasting high-temperature desulfurization section and discharged to form flue gas enriched with sulfur oxide, further realizing the resource utilization of flue gas containing sulfur dioxide. The average cylinder pressure strength of the fired ceramsite is 6.8MPa, and the water absorption rate is 9.0%, which meets the requirements of the national standard for light aggregate (GB / T17431.1~2010). The main mineral phases in the final finished ceramsite are calcium feldspar, hematite, and pyroxene, and the detected sulfur content is 0.8%. The sulfur content of ceramsite does not exceed 1%, which meets the detection content of sulfide and sulfate in ceramsite and is lower than the concentration limit of 1% in GB / T17431.2-201017 "Light Aggregate and Its Test Method Part 1: Light Aggregate".

[0040] Example 3

[0041] The present embodiment provides a method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste, with industrial byproduct desulfurized gypsum as the main raw material, slag, dredged mud and fly ash as auxiliary materials, the sulfur-containing solid waste content is 45wt%, the ground powder is used for extrusion granulator or disc granulator for granulation, the diameter of ceramsite green balls is 11mm, the average single ball compressive strength is 180N, the sulfur content of ceramsite green balls is 9.6wt%, the calcium oxide content is 13.8wt%, and the silicon oxide content is 40wt%. The ceramsite is sent to a roasting furnace for firing, and the average cylinder compressive strength of the ceramsite after firing is 8.5MPa, and the water absorption rate is 9.2%, which meets the provisions of the national standard for light aggregate (GB / T17431.1-2010). The roasting furnace refers to roasting machines, sintering machines, chain grate machine-rotary kilns, solid waste ceramsite static material roasting furnaces, tunnel kilns and other ceramsite kiln equipment that adopts exhaust roasting. The maximum roasting temperature is 1250℃. During the roasting process, the heat must be kept in the roasting and desulfurization section to ensure that the sulfate is decomposed and sulfur dioxide is fully released. The gas circulation process flow chart is as follows: Figure 7The gas circulation of ceramsite containing sulfate solid waste is drying section 1, drying section 2, preheating section, roasting desulfurization section, soaking section, cooling section 1 and cooling section 2. The temperature of the desulfurization section is 1150℃. The sulfur-rich flue gas discharged from the roasting desulfurization section passes through the preheating section and is further cooled to achieve resource utilization. The main mineral phases in the final finished ceramsite are calcium feldspar, quartz, and yellow feldspar. The detected sulfur content is 0.67%, and the sulfur content of ceramsite does not exceed 1%. The detection content of sulfide and sulfate in ceramsite must be lower than the concentration limit of 1% in GB / T 17431.2-201017 "Light Aggregates and Their Test Methods Part 1: Light Aggregates".

[0042] Example 4

[0043] This embodiment provides a method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste, wherein the sulfur-containing solid waste is industrial byproduct desulfurization ash, and the auxiliary materials are pottery clay, fly ash and dredging mud. The sulfur-containing solid waste is added in an amount of 40wt%. The ground powder is used in an extrusion granulator for granulation. The size of the ceramsite green balls is 15mm, the average single ball compressive strength is 205N, the sulfur content of the ceramsite green balls is 7.6wt%, the calcium oxide content is 15.8wt%, and the silicon oxide content is 51wt%. The ceramsite is sent to a roasting furnace for firing, wherein the gas circulation process flow chart used in the roasting furnace is as follows: Figure 7 , respectively, drying section 1, drying section 2, preheating section (600℃), roasting desulfurization section (1180℃), soaking section (1120℃), cooling section 1 and cooling section 2. The temperature of the desulfurization section is 1180℃. The sulfur-rich flue gas discharged from the roasting desulfurization section is circulated through the preheating section and further cooled to achieve resource utilization. The average cylinder compressive strength of the fired ceramsite is 9.5MPa, and the water absorption rate is 8.8%, which meets the requirements of the national standard for light aggregate (GB / T17431.1~2010). The main mineral phases in the final finished ceramsite are calcium feldspar and quartz, and the sulfur content is 0.57%. The sulfur content of ceramsite does not exceed 1%, which meets the requirements that the detection content of sulfide and sulfate in ceramsite is lower than the concentration limit of 1% in GB / T 17431.2-201017 "Light Aggregate and Its Test Methods Part 1: Light Aggregate".

[0044] Example 5

[0045] This embodiment provides a method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste, with sulfide iron waste slag as the main raw material, the mass ratio of sulfur-containing waste slag to auxiliary materials is 65:35, and the auxiliary materials are fly ash and dredged mud. The ground powder is used for extrusion granulator or disc granulator for granulation, the diameter of ceramsite green balls is 9mm, the average single ball compressive strength is 120N, the sulfur oxide content of ceramsite green balls is 7.34wt%, the calcium oxide content is 10.11wt%, and the silicon oxide content is 40.97wt%. The ceramsite is sent to a roasting furnace for firing, and the average compressive strength of the ceramsite after firing is 10MPa, and the water absorption rate is 3.4%, which meets the requirements of the national standard for light aggregate (GB / T17431.1~2010), and the cylinder pressure strength shall not be less than 5.0MPa. The roasting furnace refers to roasting machine, sintering machine, chain grate machine-rotary kiln, solid waste ceramsite static material layer roasting furnace, tunnel kiln and other ceramsite kiln equipment using exhaust roasting method. The maximum roasting temperature is 1250℃, which is drying section 1, drying section 2, ignition section, low temperature desulfurization section 400℃, high temperature desulfurization section 950℃, roasting section, soaking section, cooling section 1, cooling section 2. The gas circulation process flow chart is as follows: Figure 5 ; The high-temperature desulfurization section discharges 950℃ flue gas to assist in mixing with air, or the roasting and soaking section discharges high-temperature flue gas to adjust the wind temperature and air volume, and circulates to the low-temperature desulfurization section for heating of the expanded clay and discharges sulfur oxide-enriched flue gas, thereby realizing resource utilization of sulfur dioxide-containing flue gas; the remaining exhaust gas from the roasting and soaking sections can be heated in the drying section 2 or output as waste heat, and then treated and discharged as ordinary flue gas. The main mineral phases in the final finished expanded clay are calcium feldspar, hematite, and quartz, and the detected sulfur content is 0.9%, which meets the requirements that the detected content of sulfides and sulfates in expanded clay must be lower than the concentration limit in GB / T17431.2-201017 "Light Aggregates and Their Test Methods Part 1: Light Aggregates".

[0046] Example 6

[0047] This embodiment provides a method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste, with high-sulfur coal gangue containing pyrite as the main raw material, and auxiliary materials being desulfurized gypsum and clay, and the mass ratio of sulfur-containing coal gangue to auxiliary materials being 65:35. The ground powder is used for granulation by an extrusion granulator or a disc granulator, the diameter of the ceramsite green ball is 10mm, the average single ball compressive strength is 125N, the sulfur oxide element content of the ceramsite green ball is 7.34wt%, the calcium oxide content is 20.11wt%, and the silicon oxide content is 48.97wt%. The ceramsite is sent to a roasting furnace for firing, and the average compressive strength of the ceramsite after firing is 16MPa, and the water absorption rate is 2.0%, which meets the requirements of the national standard for light aggregate (GB / T17431.1~2010), and the cylinder pressure strength shall not be less than 5.0MPa. The roasting furnace refers to roasting machine, sintering machine, chain grate machine-rotary kiln, solid waste ceramsite static material layer roasting furnace, tunnel kiln and other ceramsite kiln equipment using exhaust roasting method. The maximum roasting temperature is 1250℃, including drying section 1, drying section 2, ignition section, low-temperature desulfurization section 500℃, high-temperature desulfurization section 1100℃, roasting section, soaking section, cooling section 1, cooling section 2. The gas circulation process flow chart is as follows: Figure 5 ; The high-temperature desulfurization section discharges 1200℃ flue gas to assist in mixing with air, or the roasting and soaking section discharges high-temperature flue gas to adjust the wind temperature and air volume, and circulates to the low-temperature desulfurization section to heat the expanded clay and discharge sulfur oxide-enriched flue gas, thereby realizing resource utilization of sulfur dioxide-containing flue gas; the remaining exhaust gas from the roasting and soaking sections can be heated in the drying section 2 or output waste heat, and then treated and discharged as ordinary flue gas. The main mineral phases in the final finished expanded clay are calcium feldspar, hematite, and quartz, with a detected sulfur content of 0.95%, and the sulfur content of expanded clay does not exceed 1%, which complies with the detection content of sulfides and sulfates in expanded clay, which must be lower than the concentration limit of 1% in GB / T 17431.2-201017 "Light Aggregates and Their Test Methods Part 1: Light Aggregates".

[0048] Example 7

[0049] The present embodiment provides a method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste, with high-sulfur tailings as the main raw material, which contains pyrite as the main sulfur-containing mineral phase, the mass ratio of high-sulfur tailings to auxiliary materials is 60:40, and the auxiliary material is shale. The ground powder is used for extrusion granulator or disc granulator for granulation, the diameter of ceramsite green balls is 10mm, the average single ball compressive strength is 220N, the sulfur oxide content in the ceramsite green balls is 6.12wt%, the calcium oxide content is 5.16wt%, and the silicon oxide content is 59.21wt%. The ceramsite is sent to a roasting furnace for firing, and the average cylinder compressive strength of the ceramsite after firing is 7.6MPa, and the water absorption rate is 9.9%, which meets the requirements of the national standard for light aggregate (GB / T17431.1~2010), and the cylinder compressive strength shall not be less than 5.0MPa. The roasting furnace refers to the ceramsite roasting machine, the highest roasting temperature is 1200℃, including drying section 1, drying section 2, ignition section, low temperature desulfurization section 550℃, high temperature desulfurization section 600℃, roasting section 1180℃, soaking section 1130℃, cooling section 1, cooling section 2. The gas circulation process flow chart is as follows: Figure 8 , the 400-600℃ desulfurization roasting section is divided into two desulfurization sections of 350-600 and 600-900℃, and the flue gas of the high-temperature desulfurization section is circulated to the low-temperature desulfurization section to enrich sulfur oxides and then discharge the flue gas, further realizing the resource utilization of flue gas containing sulfur dioxide. The sulfur content of the final finished ceramsite is 0.79%, and the main mineral phases are calcium feldspar, hematite, and quartz. The sulfur content of ceramsite does not exceed 1%, which meets the detection content of sulfides and sulfates in ceramsite and is lower than the concentration limit of 1% in GB / T17431.2-201017 "Light Aggregates and Their Test Methods Part 1: Light Aggregates".

[0050] Comparative Example

[0051] This comparative example is similar to Example 1, except that the temperature of the desulfurization section in this comparative example is 900°C (not within the scope of protection of this application). The sulfur content of the final finished ceramsite is 1.95%, and the sulfur content of the ceramsite exceeds 1%, which does not meet the requirement that the sulfide and sulfate content of the ceramsite should be lower than the concentration limit of 1% in GB / T 17431.2-201017 "Light Aggregates and Test Methods Part 1: Light Aggregates".

[0052] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste, characterized in that: The following steps are involved: S1. Mixing the sulfur-containing solid waste with auxiliary materials to prepare ceramsite green balls, wherein the raw materials of the ceramsite green balls include 40-65 parts of the sulfur-containing solid waste and 35-60 parts of the auxiliary materials by weight, and the weight percentage of sulfur in the ceramsite green balls exceeds 5%, the weight percentage of calcium oxide is 5.16-22.11%, and the weight percentage of silicon oxide is 38.97-59.21%; S2, sending the ceramsite green balls to a roasting furnace for roasting, maintaining high temperature to release sulfur dioxide, enriching and collecting sulfur dioxide, and obtaining sintered ceramsite.

2. The method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste according to claim 1, characterized in that: The sulfur-containing solid waste described in S1 is solid waste containing one or more of sulfate, sulfite and sulfide.

3. The method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste according to claim 2, characterized in that: The sulfur-containing solid waste in S1 contains sulfide, and the temperature of the high-temperature insulation is 400-600°C.

4. The method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste according to claim 2, characterized in that: The sulfur-containing solid waste in S1 contains sulfite or sulfate, and the temperature of the high-temperature insulation is 950-1180°C.

5. The method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste according to claim 2, characterized in that: The sulfur-containing solid waste in S1 contains sulfide and sulfate, and the high-temperature insulation is carried out at 400-600° C. and 950-1180° C. in sequence.

6. The method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste according to claim 2, characterized in that: The sulfur-containing solid waste in S1 is one or more of rotary kiln waste slag, pyrite slag, desulfurized gypsum, industrial by-product desulfurized gypsum, sulfur-containing waste slag, and high-sulfur tailings.

7. The method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste according to claim 1, characterized in that: The auxiliary materials described in S1 are one or more of shale, clay, slag, fly ash, dredged mud, and desulfurized gypsum.

8. The method for preparing ceramsite and enriching sulfur oxide gas using sulfur-containing solid waste according to claim 1, characterized in that: The size of the ceramsite raw balls described in S1 is 9-15 mm.

9. The method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste according to claim 1, characterized in that: The sulfur dioxide described in S2 is used to prepare sulfuric acid or sulfate.

10. The method for preparing ceramsite and enriching sulfur oxide gas by using sulfur-containing solid waste according to claim 1, characterized in that: The mass percentage of sulfur in the sintered ceramsite is less than 2%, and the mineral phase is one or more of anorthite, hematite, quartz, orthoclase and pyroxene.

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