CN110484715B - Desulfurization ash treatment method - Google Patents
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- 238000000034 method Methods 0.000 title claims abstract description 46
- 238000006477 desulfuration reaction Methods 0.000 title claims abstract description 42
- 230000023556 desulfurization Effects 0.000 title claims abstract description 42
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 72
- 239000010881 fly ash Substances 0.000 claims abstract description 72
- 239000002956 ash Substances 0.000 claims abstract description 65
- 238000010438 heat treatment Methods 0.000 claims abstract description 29
- 238000004321 preservation Methods 0.000 claims abstract description 12
- 238000006243 chemical reaction Methods 0.000 claims description 72
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 34
- 229910052925 anhydrite Inorganic materials 0.000 claims description 27
- 229910052799 carbon Inorganic materials 0.000 claims description 22
- 230000001681 protective effect Effects 0.000 claims description 20
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims description 13
- 239000007795 chemical reaction product Substances 0.000 claims description 12
- 239000000047 product Substances 0.000 claims description 11
- 239000000843 powder Substances 0.000 claims description 8
- 238000007664 blowing Methods 0.000 claims description 6
- 239000003245 coal Substances 0.000 claims description 5
- 238000001035 drying Methods 0.000 claims description 5
- 238000005303 weighing Methods 0.000 claims description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 abstract description 22
- 238000005245 sintering Methods 0.000 abstract description 20
- 229910052742 iron Inorganic materials 0.000 abstract description 11
- 239000000126 substance Substances 0.000 abstract description 11
- 230000004907 flux Effects 0.000 abstract description 8
- 238000004064 recycling Methods 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 45
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 17
- 230000008569 process Effects 0.000 description 15
- 238000000354 decomposition reaction Methods 0.000 description 14
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 11
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 10
- 239000000292 calcium oxide Substances 0.000 description 10
- 235000012255 calcium oxide Nutrition 0.000 description 10
- 239000011593 sulfur Substances 0.000 description 10
- 229910052717 sulfur Inorganic materials 0.000 description 10
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 8
- 239000003546 flue gas Substances 0.000 description 8
- 239000002994 raw material Substances 0.000 description 7
- 239000007787 solid Substances 0.000 description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 238000011160 research Methods 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 5
- 239000011261 inert gas Substances 0.000 description 4
- 230000004048 modification Effects 0.000 description 4
- 238000012986 modification Methods 0.000 description 4
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- 238000002347 injection Methods 0.000 description 3
- 239000007924 injection Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 238000007254 oxidation reaction Methods 0.000 description 3
- 230000009467 reduction Effects 0.000 description 3
- 238000006722 reduction reaction Methods 0.000 description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 2
- 239000000571 coke Substances 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000005501 phase interface Effects 0.000 description 2
- 239000001117 sulphuric acid Substances 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 235000002918 Fraxinus excelsior Nutrition 0.000 description 1
- 206010024769 Local reaction Diseases 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- GBAOBIBJACZTNA-UHFFFAOYSA-L calcium sulfite Chemical compound [Ca+2].[O-]S([O-])=O GBAOBIBJACZTNA-UHFFFAOYSA-L 0.000 description 1
- 235000010261 calcium sulphite Nutrition 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000029087 digestion Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- NIFIFKQPDTWWGU-UHFFFAOYSA-N pyrite Chemical compound [Fe+2].[S-][S-] NIFIFKQPDTWWGU-UHFFFAOYSA-N 0.000 description 1
- 229910052683 pyrite Inorganic materials 0.000 description 1
- 239000011028 pyrite Substances 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000006479 redox reaction Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000012265 solid product Substances 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
- 238000009270 solid waste treatment Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 235000011149 sulphuric acid Nutrition 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/02—Roasting processes
- C22B1/10—Roasting processes in fluidised form
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/14—Agglomerating; Briquetting; Binding; Granulating
- C22B1/16—Sintering; Agglomerating
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Environmental & Geological Engineering (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention discloses a desulfurized fly ash treatment method, and belongs to the technical field of iron ore sintering. The method comprises the steps of carrying out first-stage heat preservation on dried desulfurization ash at the temperature of T1-747 ℃, adding carbon powder, heating to the temperature of T2-812-887 ℃, and carrying out second-stage heat preservation, so as to obtain the desulfurization ash treatment product. The desulfurized fly ash treatment substance can replace a CaO flux for sintering the iron ore and return to the sintering of the iron ore, thereby realizing the effective treatment and recycling of the desulfurized fly ash and solving the problems that the desulfurized fly ash occupies land and pollutes the environment.
Description
Technical Field
The invention relates to the technical field of iron ore sintering, in particular to a desulfurized fly ash treatment method.
Background
SO discharged by iron and steel enterprises in China250-70% of the total sulfur content comes from a sintering process, a semi-dry desulfurization technology is generally adopted in the prior art for sintering flue gas desulfurization, the method is low in investment and high in desulfurization rate, but a large amount of desulfurization ash is generated in the semi-dry desulfurization process, and the desulfurization ash is mainly subjected to stack treatment at present. Because the desulfurized fly ash contains a large amount of CaSO with unstable properties3The method can cause resource waste, environmental pollution and land occupation, so that how to treat the desulfurized fly ash becomes a current research hotspot.
In addition, with the increasing requirements of our country on solid waste treatment, the researchers pay attention to how to better comprehensively treat and utilize the sinter flue gas desulfurization ash. A great deal of research is carried out on the comprehensive utilization of the flue gas desulfurization ash of the sinter in many colleges and enterprises, and the research mainly comprises backfilling, road building, acid soil improvement, autoclaved brick making, dry powder mortar making, ceramsite, cement retarder preparation, CaSO preparation after modification and oxidation4The method starts to treat the desulfurized ash in the aspects of whiskers and the like. However, the existing research only stays in a laboratory stage, and the solid waste digestion and treatment function of the metallurgical enterprises is neglected.
Found by search, the Tangchao boiling furnace is doped with the semi-dry method sintering flue gas desulfurization ash to prepare SO2Basic research on applications of (Wuhan science and technology university Master theory)In article 2016, it is mentioned that SO is obtained by roasting desulphurised ash in a fluidized bed furnace with sulphuric acid2Study of CaSO conditions of different oxygen partial pressures3The decomposition condition and the reaction behavior of feeding the mixture of the desulfurized fly ash, the pyrite and the ferrous sulfate from the lower part of the fluidized bed furnace are also researched. The main objective of this study was to obtain SO by thermal decomposition of sulfur-containing species2Sulfuric acid is produced, but the sulfur content of S in the residual products after decomposition is very high, and the decomposed solid products are difficult to be effectively utilized.
"Panzhihua science and information" 2014 (3): 26-30, the idea of the semi-dry desulfurized fly ash pyrolysis process is to use coke oven or blast furnace gas as a heat source and a reducing medium, and to use a fluidized bed process to pyrolyze the semi-dry desulfurized fly ash to form active calcium oxide and sulfur-rich flue gas, wherein the calcium oxide is returned to be used as a sintering flux, and the sulfur-containing flue gas is recovered to be used for preparing sulfuric acid. But CaSO still exists3Oxidation reaction to generate CaSO4Meanwhile, if the CO concentration is too high, CaSO will be generated3The reduction to CaS results in a sharp increase in the residual amount of S in the decomposition products, which makes it difficult to effectively return to the problem of utilization in the sintering process. In addition, coke oven or blast furnace gas contains a large amount of CO2、N2Etc. will greatly dilute SO2Concentration affects the production of sulfuric acid.
Wang et al, a new process for utilization of flue gas desulfurization ash by semidry process, journal of engineering thermophysics, 2011, V32 (6): 1077 and 1079, the semi-dry desulfurization ash is decomposed and utilized in an oxygen-free atmosphere, the temperature of a high-temperature reactor is set to 800-900 ℃, and the CaSO can be effectively decomposed3However, this process does not allow the CaSO in the feedstock to be present4The decomposition can cause that the calcium oxide of the reaction product contains a large amount of CaSO4Limiting its effective processing and utilization.
Therefore, it is urgently needed to develop a method for treating desulfurized fly ash with low cost and high efficiency, and achieve the economic and environmental-friendly goals of harmless and comprehensive resource utilization of desulfurized fly ash.
Disclosure of Invention
1. Technical problem to be solved by the invention
The invention aims to solve the problem that the sintering ore flue gas desulfurization ash is difficult to treat and recycle in the prior art, and provides a desulfurization ash treatment method.
2. Technical scheme
In order to achieve the purpose, the technical scheme provided by the invention is as follows:
adding the dried desulfurized fly ash into a reaction vessel, introducing protective gas into the reaction vessel, heating to T1 temperature under the condition of the protective gas, and carrying out first-stage heat preservation; then adding carbon powder into the reaction container, continuously heating to T2 temperature, and carrying out second-stage heat preservation; wherein T1 is 747-812 deg. C, T2 is 812-887 deg. C.
Preferably, after the desulfurized fly ash is heated to the temperature T1 for the first-stage heat preservation, the reaction product SO in the reaction vessel is detected2When the concentration of SO is2When the concentration of (B) is less than 10ppm, carbon powder is added to the reaction vessel.
Preferably, the specific steps of the desulfurized fly ash treatment are as follows:
s10, drying and weighing the desulfurized fly ash to obtain dry desulfurized fly ash with mass m, and detecting CaSO in the dry desulfurized fly ash4Is w1, Fe2O3W 2;
s20, calculating CaSO in the desulfurized fly ash4And Fe2O3Respectively has a mass of mCaSO4And mFe2O3Adding desulfurized ash into a reaction vessel, and introducing protective gas;
s30, heating the desulfurized ash to T1 temperature under the condition of protective gas, carrying out first-stage heat preservation, and detecting a reaction product SO in the reaction container2When the concentration of SO is2When the concentration of (2) is less than 10ppm, adding carbon powder with the mass of Wc into the reaction container;
S40、continuously heating to T2 temperature, carrying out second stage heat preservation, and detecting reaction product SO in the reaction container2When the concentration of SO is2When the concentration of (A) is 0, stopping heating to obtain a desulfurized fly ash treatment product;
wherein T1 is 747-812 deg. C, T2 is 812-887 deg. C.
Preferably, the step S30 of adding carbon powder specifically includes: and (3) blowing carbon powder into the reaction vessel by using protective gas, wherein the gas flow is Q2, the blowing time is 10 seconds, and then reducing the gas flow to Q1, wherein Q2 is more than or equal to 100Q 1.
Preferably, the amount of the carbon powder added in step S30 is:
Wc＝γ×(12×mCaSO4/MCaSO4+36×mFe2O3/MFe2O3) /Dc, wherein
Wc: amount of carbon powder, g;
γ: the reaction coefficient;
dc: carbon content in carbon powder,%;
mCaSO4: CaSO in dry desulfurized fly ash4Content, g;
MCaSO4：CaSO4molar mass, g/mol;
mFe2O3: fe in dry desulphurised ash2O3Content, g;
MFe2O3：Fe2O3molar mass, g/mol.
Preferably, the carbon powder added in step S30 includes coke powder or coal powder.
Preferably, the carbon content Dc in the carbon powder is 75% to 85%.
Preferably, γCoefficient of reactionThe range of (1) is 1.364 to 2.224.
3. Advantageous effects
Compared with the prior art, the technical scheme provided by the invention has the following remarkable effects:
(1) according to the desulfurization ash treatment method, the temperature rise gradient of desulfurization ash treatment is set, and the desulfurization ash is subjected to carbon distribution treatment, so that sulfur elements in the desulfurization ash are effectively removed, and a desulfurization ash treatment substance is obtained; the desulfurized fly ash treatment substance obtained by the invention can replace CaO flux for sintering to return to iron ore for sintering, and the problems that desulfurized fly ash in the prior art can not be effectively treated and recycled, and the desulfurized fly ash occupies land and pollutes the environment are fully solved;
(2) the desulfurization ash treatment method provided by the invention comprises the following steps of preserving heat of desulfurization ash at the temperature of 747-812 ℃ for anaerobic heating decomposition to enable CaSO3*0.5H2Completely decomposing O, adding carbon powder, and heating to 812-887 ℃ until CaSO in the desulfurized ash is completely decomposed4Completely decomposing to obtain a desulfurized fly ash treatment substance, and continuously heating the desulfurized fly ash after carbon preparation to 812-887 ℃ to ensure that CaSO in the desulfurized fly ash4The decomposition is complete, and the energy consumption in the desulfurization ash treatment process is greatly reduced;
(3) the desulfurization ash treatment method creatively and reasonably mixes carbon in the desulfurization ash so as to realize CaSO4The solid-solid reaction coefficient gamma in the process of reducing calcium sulfate from carbon, and CaSO contained in the desulfurized fly ash raw material4And CaSO in anaerobic decomposition3·0.5H2O and Fe2O3CaSO generated by oxidation-reduction reaction4Considering carbon distribution amount in three aspects, and designing a specific carbon powder carbon distribution amount calculation formula as Wc ═ γ × (12 × m)CaSO4/MCaSO4+36×mFe2O3/MFe2O3) The range of/Dc, gamma is 1.364-2.224;
(4) according to the desulfurization ash treatment method, carbon powder enters the reaction container in a gas injection mode, the gas flow is Q2, so that gas and desulfurization ash form convolution in the reaction container, the sufficient and uniform mixing of the carbon powder and the desulfurization ash is increased, the gas flow is reduced to Q1 after 10s of injection, Q2 is more than or equal to 100Q1, and the CaSO is caused at the moment4Start decomposition, reduce gas flow to facilitate SO2Decomposition of (2);
(5) according to the desulfurization ash treatment method, the content of the S element in the obtained desulfurization ash treatment substance is reduced to the minimum, and the desulfurization ash treatment substance can replace a CaO flux for sintering to be recycled to the field of iron ore sintering; the desulfurized ash treatment substance is mixed with an external flux to obtain a mixed flux, the mass percentage of the desulfurized ash treatment substance in the mixed flux is controlled to be 20-40%, the liquidity of the liquid phase of the sintered iron ore powder can be improved, the quality index of the sintered product and the metallurgical performance of the sintered ore are obviously improved, the consumption of the sintered fuel is reduced, and the effective treatment and recycling of the desulfurized ash can be realized.
Drawings
FIG. 1 is a schematic flow diagram of a desulfurized fly ash treatment process of the present invention.
Detailed Description
The detailed description and exemplary embodiments of the invention will be better understood when read in conjunction with the appended drawings, where the elements and features of the invention are identified by reference numerals.
The structure, proportion, size and the like shown in the drawings are only used for matching with the content disclosed in the specification, so that the person skilled in the art can understand and read the description, and the description is not used for limiting the limit condition of the implementation of the invention, so the method has no technical essence, and any structural modification, proportion relation change or size adjustment still falls within the scope of the technical content disclosed by the invention without affecting the effect and the achievable purpose of the invention. Meanwhile, the terms such as "upper", "lower", "left", "right" and "middle" used in the present specification are for clarity of description only, and are not used to limit the implementable scope, and the relative relationship changes or adjustments may be considered to be within the implementable scope of the present invention without substantial technical changes; in addition, the embodiments of the present invention are not independent of each other, but may be combined.
Example 1
As shown in FIG. 1, the method for treating desulfurized fly ash of the present invention comprises the following steps:
s10, drying 500g of raw material desulfurized fly ash in vacuum at 105 ℃ for 4h, weighing to obtain dried desulfurized fly ash, taking 100g of dried desulfurized fly ash, and detecting CaSO in the dried desulfurized fly ash4W 1-2.50% by mass, Fe2O3The mass fraction of (a) is w 2-1.21%;
s20, calculating CaSO in the dry desulfurized fly ash4And Fe2O3Respectively has a mass of mCaSO42.50g and mFe2O3Adding 1.21g of dry desulfurized ash into a reaction vessel, introducing protective gas into the reaction vessel to discharge oxygen in the reaction vessel, wherein the protective gas is inert gas or N2A gas, in this embodiment the protective gas is N2The gas flow rate is Q1 ═ 0.5L/min;
s30, heating the dry desulfurized ash to T1 temperature under the condition of protective gas, wherein the heating rate is 10 ℃/min, the T1 is 800 ℃, and carrying out first-stage heat preservation, wherein CaSO is kept at the time3*0.5H2Decomposition of O to SO2，SO2Is discharged from the pipeline and oxidized into SO by a catalytic device3For the preparation of sulphuric acid; detecting reaction product SO in reaction vessel2When the concentration of SO is2When the concentration of (B) is less than 10ppm, N is used2Injecting gas into a reaction container, and adding carbon powder with the mass Wc of 1.21g into the reaction container, wherein the carbon powder comprises coke powder or coal powder, the carbon content Dc in the carbon powder is 75-85%, the carbon powder used in the embodiment is coke powder, the granularity of the coke powder is less than 200 meshes, and the carbon content Dc is 81.25%;
it is worth to be noted that the gas flow of the injected carbon powder is Q2, and the injection time is 10 seconds, so that the gas and the desulfurized ash form convolution in the reaction vessel, and the sufficient and uniform mixing of the carbon powder and the desulfurized ash is increased; then the gas flow is reduced to Q1, and Q2 is more than or equal to 100Q1, because the CaSO4Start decomposition, reduce gas flow to facilitate SO2Decomposition of (3). In the embodiment, Q1 is 0.5L/min; q2 ═ 50L/min.
S40, adding carbon powder, heating to T2 deg.C at 10 deg.C/min and T2 at 830 deg.C, maintaining the temperature at the second stage, and detecting the reaction product SO in the reaction container2When the concentration of SO is2When the concentration of (D) is 0, the heating is stopped to obtain a desulfurized fly ash.
It should be noted that, in the prior art, the research on the utilization of the desulfurized ash by those skilled in the art mainly focuses on the oxidation and stability of calcium sulfite, but this treatment method results in low utilization rate of the desulfurized ash, and the desulfurized ash still escapes a large amount of pollutants during the treatment process, and cannot achieve the purpose of effective treatment of the desulfurized ash. The method overcomes the difficulty in the prior art, sets the temperature rise gradient of the desulfurized fly ash, and simultaneously carries out carbon blending treatment on the desulfurized fly ash to separate out sulfur in the desulfurized fly ash.
The desulfurization ash treatment method of the invention carries out anaerobic heating on the dried desulfurization ash, and when the heating temperature is raised to T1-747-812 ℃, the temperature is kept to promote CaSO in the desulfurization ash3·0.5H2Completely decomposing O, adding carbon powder into the desulfurized ash, raising the temperature to T2-812-887 ℃, and then preserving the heat, wherein CaSO is used at the moment4+C＝CaO+SO2+ CO, promoting the sulphur in the desulphurised ashes as SO2The form of the sulfur-containing gas is completely discharged, the content of S element in the obtained desulfurization ash treatment substance is reduced to the minimum, the desulfurization ash treatment substance can be effectively recycled to iron ore sintering, and SO in the gas product is2Can be used for preparing sulfuric acid.
It is also noted that the main component of the desulfurized fly ash is CaSO3·0.5H2O、CaCO3、Ca(OH)2、CaSO4、Fe2O3And some gangue components, the prior art generally selects to directly return desulfurized ash to sintering for utilization as CaO flux due to CaSO3Is easily oxidized into CaSO under the oxygen-containing atmosphere4The residual sulfur in the sintered ore aggravates the increase of the sulfur content in the sintered ore and is not beneficial to blast furnace smelting, so the thermal decomposition of the desulfurized fly ash is carried out in an oxygen-free environment. Adding desulfurized ash into a reaction vessel, and introducing inert gas or N2Discharging the oxygen in the container, heating and carbon preparation.
In addition, according to the decomposition thermodynamic conditions of the main components of the desulfurized fly ash, the invention designs a calculation formula of the carbon content of the specific carbon powder as follows:
Wc＝γ×(12×mCaSO4/MCaSO4+36×mFe2O3/MFe2O3)/Dc，
wherein Wc: amount of carbon powder, g; γ: the solid-solid reaction coefficient of the process of carbon reduction of calcium sulfate is dimensionless; dc: carbon content in carbon powder,%; m isCaSO4: CaSO in the raw Material4Content, g; mCaSO4：CaSO4Molar mass, g/mol；mFe2O3: fe in the raw material2O3Content, g; mFe2O3：Fe2O3Molar mass, g/mol.
It is noted that γ in the formulaCoefficient of reactionIn the range of 1.364 to 2.224, preferably gammaCoefficient of reactionThe range is 1.5 to 2.0.
In the experimental conditions of this example, the process of carbon reduction of calcium sulfate is a solid-solid reaction, and the kinetic equation is applicable to a homogeneous reaction under isothermal conditions:
wherein α is the percent conversion of reactant to product, t is time, k (T) is the temperature dependence of the rate constant, and f (α) is a function of the reaction mechanism;
in the solid homogeneous reaction kinetics:
k(T)＝ATB
wherein A is a pre-exponential factor; t is the temperature; b is a reaction index;
the reaction is carried out on a phase interface where the calcium sulfate particles and the solid carbon particles are contacted, a local reaction active area exists at the interface, and therefore the reaction progress is characterized by a phase interface reaction kinetic mode function:
wherein n is the apparent reaction stage number; d α/dt is the theoretical reaction rate, the actual reaction rate is lower than the theoretical value, and therefore a reaction correction factor γ is introduced;
wherein v represents the actual reaction rate; through calculation of an empirical formula, for the homogeneous isothermal one-dimensional diffusion solid reaction, the pre-factor A is 3, the reaction response stage number is 3/4, the reaction index B is-3/4, at the reaction end point, the calcium sulfate is reacted by 98%, and the reaction correction coefficients at different temperatures are shown in the following table 1:
TABLE 1 relationship between reaction temperature and solid-solid reaction coefficient
In this example, the reaction temperature of T2 is 830 ℃, so that γ takes the value of 1.997.
As a result of analyzing the main chemical components of the desulfurized fly ash treated material obtained by the desulfurized fly ash treatment method of this example, as shown in table 2, the S content of the treated material was reduced from 13.78% in the original raw material to 0.02%, the S content of the quick lime used in the sintering site was usually 0.05% to 0.10%, and the S content of the quick lime obtained in this example was reduced by 60% as compared with the quick lime used in the sintering site.
TABLE 2 desulfurized fly ash XRF results after decomposition
Example 2
The basic content of this example is the same as example 1, except that the method for treating desulfurized fly ash of this example comprises the following steps:
s10, drying 500g of raw material desulfurized fly ash in vacuum at 105 ℃ for 4h, weighing to obtain dried desulfurized fly ash, taking 100g of dried desulfurized fly ash, and detecting CaSO in the dried desulfurized fly ash4W 1-2.50% by mass, Fe2O3The mass fraction of (a) is w 2-1.21%;
s20, calculating CaSO in the dry desulfurized fly ash4And Fe2O3Respectively has a mass of mCaSO42.50g and mFe2O3Adding 1.21g of dry desulfurized ash into a reaction vessel, introducing protective gas into the reaction vessel to discharge oxygen in the reaction vessel, wherein the protective gas is inert gas or N2A gas, in this embodiment the protective gas is N2Gas, gasThe volume flow rate is Q1 ═ 0.5L/min;
s30, heating the dry desulfurized ash to a temperature of T1 under the condition of protective gas, wherein the heating rate is 10 ℃/min, and the temperature of T1 is 747 ℃, and carrying out first-stage heat preservation; detecting reaction product SO in reaction vessel2When the concentration of SO is2When the concentration of (B) is less than 10ppm, N is used2Injecting gas into a reaction container, and adding carbon powder with the mass of Wc being 1.17g, wherein the carbon powder comprises coke powder or coal powder, and the carbon content Dc in the carbon powder is 75%;
in the embodiment, the gas flow of the blown carbon powder is Q2, the blowing time is 10 seconds, and then the gas flow is reduced to Q1, wherein Q2 is more than or equal to 100Q1, and Q1 is 0.5L/min; q2 ═ 50L/min.
S40, adding carbon powder, heating to T2 deg.C at a heating rate of 10 deg.C/min and T2 ═ 850 deg.C, maintaining the temperature at the second stage, and detecting the reaction product SO in the reaction container2When the concentration of SO is2When the concentration of (D) is 0, the heating is stopped to obtain a desulfurized fly ash.
The reaction temperature of T2 in this example was 850 ℃ and therefore γCoefficient of reactionThe value is 1.778. The content of the S element in the desulfurized fly ash treated product obtained by the desulfurized fly ash treatment method of the embodiment is reduced to 0.017% at minimum, and the desulfurized fly ash treated product can be recycled to iron ore sintering.
Example 3
The basic content of this example is the same as example 1, except that the method for treating desulfurized fly ash of this example comprises the following steps:
s10, drying 500g of raw material desulfurized fly ash in vacuum at 105 ℃ for 4h, weighing to obtain dried desulfurized fly ash, taking 100g of dried desulfurized fly ash, and detecting CaSO in the dried desulfurized fly ash4W 1-2.50% by mass, Fe2O3The mass fraction of (a) is w 2-1.21%;
s20, calculating CaSO in the dry desulfurized fly ash4And Fe2O3Respectively has a mass of mCaSO42.50g and mFe2O3Adding 1.21g of dry desulfurized ash into a reaction vessel, introducing protective gas into the reaction vessel to discharge oxygen in the vessel, wherein the protective gas is inertGas or N2A gas, in this embodiment the protective gas is N2The gas flow rate is Q1 ═ 0.5L/min;
s30, heating the dry desulfurized ash to T1 temperature under the condition of protective gas, wherein the heating rate is 10 ℃/min, and the T1 is 812 ℃, and carrying out first-stage heat preservation; detecting reaction product SO in reaction vessel2When the concentration of SO is2When the concentration of (B) is less than 10ppm, N is used2Injecting gas into a reaction container, and adding carbon powder with the mass of Wc being 1.03g, wherein the carbon powder comprises coke powder or coal powder, and the carbon content Dc in the carbon powder is 75%;
in the embodiment, the gas flow of the blown carbon powder is Q2, the blowing time is 10 seconds, and then the gas flow is reduced to Q1, wherein Q2 is more than or equal to 100Q1, and Q1 is 0.5L/min; q2 ═ 50L/min.
S40, adding carbon powder, heating to T2 deg.C at a heating rate of 10 deg.C/min and T2 of 870 deg.C, maintaining the temperature at the second stage, and detecting the reaction product SO in the reaction container2When the concentration of SO is2When the concentration of (D) is 0, the heating is stopped to obtain a desulfurized fly ash.
The T2 reaction temperature in this example was 870 ℃ and therefore γCoefficient of reactionThe value is 1.561. The content of the S element in the desulfurized fly ash treated product obtained by the desulfurized fly ash treatment method of this embodiment is reduced to a minimum of 0.015%, and the desulfurized fly ash treated product can be recycled to iron ore sintering.
The invention has been described in detail hereinabove with reference to specific exemplary embodiments thereof. It will, however, be understood that various modifications and changes may be made without departing from the scope of the invention as defined in the appended claims. The detailed description and drawings are to be regarded as illustrative rather than restrictive, and any such modifications and variations are intended to be included within the scope of the present invention as described herein. Furthermore, the background is intended to be illustrative of the state of the art as developed and the meaning of the present technology and is not intended to limit the scope of the invention or the application and field of application of the invention.
More specifically, although exemplary embodiments of the invention have been described herein, the invention is not limited to these embodiments, but includes any and all embodiments modified, omitted, combined (e.g., between various embodiments), adapted and/or substituted as would be recognized by those skilled in the art from the foregoing detailed description. The limitations in the claims are to be interpreted broadly based the language employed in the claims and not limited to examples described in the foregoing detailed description or during the prosecution of the application, which examples are to be construed as non-exclusive. For example, in the present invention, the term "preferably" is not exclusive, and it means "preferably, but not limited to" herein. Any steps recited in any method or process claims may be executed in any order and are not limited to the order presented in the claims. The scope of the invention should, therefore, be determined only by the appended claims and their legal equivalents, rather than by the descriptions and examples given above.
Claims (4)
1. A desulfurization ash treatment method is characterized in that: the specific steps of the desulfurized fly ash treatment are as follows:
s10, drying and weighing the desulfurized fly ash to obtain dry desulfurized fly ash with mass m, and detecting CaSO in the dry desulfurized fly ash4Is w1, Fe2O3W 2;
s20, calculating CaSO in the desulfurized fly ash4And Fe2O3Respectively has a mass of mCaSO4And mFe2O3Adding desulfurized ash into a reaction vessel, and introducing protective gas;
s30, heating the desulfurized ash to T1 temperature under the condition of protective gas, carrying out first-stage heat preservation, and detecting a reaction product SO in the reaction container2When the concentration of SO is2When the concentration of (2) is less than 10ppm, adding carbon powder with the mass of Wc into the reaction container;
s40, continuously heating to T2 temperature, carrying out second stage heat preservation, and detecting reaction product SO in the reaction container2When the concentration of SO is2When the concentration of (A) is 0, stopping heating to obtain a desulfurized fly ash treatment product;
wherein T1 is 747-812 deg.C, T2 is 812-887 deg.C; carbon added in step S30The powder amount is: wc ═ γ × (12 × m)CaSO4/MCaSO4+36×mFe2O3/MFe2O3)/Dc；
And, wherein Wc: amount of carbon powder, g;
γ: the reaction coefficient;
dc: carbon content in carbon powder,%;
mCaSO4: CaSO in dry desulfurized fly ash4Content, g;
MCaSO4：CaSO4molar mass, g/mol;
mFe2O3: fe in dry desulphurised ash2O3Content, g;
MFe2O3：Fe2O3molar mass, g/mol;
γcoefficient of reactionThe range of (1) is 1.364 to 2.224.
2. The desulfurization ash treatment method according to claim 1, wherein the specific step of adding carbon powder in step S30 is as follows: and (3) blowing carbon powder into the reaction vessel by using protective gas, wherein the gas flow is Q2, the blowing time is 10 seconds, and then reducing the gas flow to Q1, wherein Q2 is more than or equal to 100Q 1.
3. The desulfurization ash treatment method according to claim 1, characterized in that: the carbon powder added in step S30 includes coke powder or coal powder.
4. The desulfurization ash treatment method according to claim 1, characterized in that: the carbon content Dc in the carbon powder is 75-85%.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101462698A (en) * | 2009-01-13 | 2009-06-24 | 南京师范大学 | Industrial method for cyclic utilization of ironmaking production desulfurized gypsum and blast furnace gas |
| CN103418598A (en) * | 2013-07-11 | 2013-12-04 | 江苏卓易环保科技有限公司 | Novel system and method for recovery of anaerobic thermal decomposition of desulfurized fly ash |
| CN103482584A (en) * | 2012-06-15 | 2014-01-01 | 南京理工大学 | Production technology for preparing calcium oxide and sulfur dioxide through utilizing desulfurized gypsum |
| CN109593953A (en) * | 2018-12-20 | 2019-04-09 | 张家港宏昌钢板有限公司 | Method for synergistic resource utilization of semidry desulfurization ash and titanium dioxide byproduct copperas |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101462698A (en) * | 2009-01-13 | 2009-06-24 | 南京师范大学 | Industrial method for cyclic utilization of ironmaking production desulfurized gypsum and blast furnace gas |
| CN103482584A (en) * | 2012-06-15 | 2014-01-01 | 南京理工大学 | Production technology for preparing calcium oxide and sulfur dioxide through utilizing desulfurized gypsum |
| CN103418598A (en) * | 2013-07-11 | 2013-12-04 | 江苏卓易环保科技有限公司 | Novel system and method for recovery of anaerobic thermal decomposition of desulfurized fly ash |
| CN109593953A (en) * | 2018-12-20 | 2019-04-09 | 张家港宏昌钢板有限公司 | Method for synergistic resource utilization of semidry desulfurization ash and titanium dioxide byproduct copperas |
Non-Patent Citations (2)
| Title |
|---|
| 半干法脱硫灰制硫酸-粉煤灰同步提取氧化铝的研究;牟雅琴;《中国优秀硕士学位论文全文数据库 工程科技I辑》;20111115;27-28 * |
| 沸腾炉掺烧半干法烧结烟气脱硫灰制备SO2的应用基础研究;唐超;《中国优秀硕士学位论文全文数据库 工程科技I辑》;20170615;22-23 * |
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