CN114292124A - Ceramsite fired by fly ash and preparation method and application thereof - Google Patents
Ceramsite fired by fly ash and preparation method and application thereof Download PDFInfo
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- CN114292124A CN114292124A CN202210129530.0A CN202210129530A CN114292124A CN 114292124 A CN114292124 A CN 114292124A CN 202210129530 A CN202210129530 A CN 202210129530A CN 114292124 A CN114292124 A CN 114292124A
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- 239000010881 fly ash Substances 0.000 title claims abstract description 135
- 238000002360 preparation method Methods 0.000 title claims abstract description 26
- 239000010802 sludge Substances 0.000 claims abstract description 113
- 238000000197 pyrolysis Methods 0.000 claims abstract description 48
- 239000000460 chlorine Substances 0.000 claims abstract description 41
- 239000000126 substance Substances 0.000 claims abstract description 36
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 34
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 34
- 239000010813 municipal solid waste Substances 0.000 claims abstract description 14
- 229910052742 iron Inorganic materials 0.000 claims abstract description 13
- 239000002994 raw material Substances 0.000 claims description 65
- 238000000034 method Methods 0.000 claims description 36
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 26
- 229910052593 corundum Inorganic materials 0.000 claims description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 26
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 26
- 229910001845 yogo sapphire Inorganic materials 0.000 claims description 26
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 claims description 25
- 239000000463 material Substances 0.000 claims description 25
- 239000007790 solid phase Substances 0.000 claims description 25
- KKCBUQHMOMHUOY-UHFFFAOYSA-N Na2O Inorganic materials [O-2].[Na+].[Na+] KKCBUQHMOMHUOY-UHFFFAOYSA-N 0.000 claims description 21
- 239000000843 powder Substances 0.000 claims description 21
- 238000001035 drying Methods 0.000 claims description 18
- 239000011268 mixed slurry Substances 0.000 claims description 14
- 238000010335 hydrothermal treatment Methods 0.000 claims description 13
- 238000000227 grinding Methods 0.000 claims description 11
- 239000007787 solid Substances 0.000 claims description 11
- 239000000919 ceramic Substances 0.000 claims description 10
- 238000007873 sieving Methods 0.000 claims description 10
- 239000002245 particle Substances 0.000 claims description 9
- 239000004566 building material Substances 0.000 claims description 6
- 238000002156 mixing Methods 0.000 claims description 6
- 239000012298 atmosphere Substances 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 5
- 239000007788 liquid Substances 0.000 claims description 5
- 238000000926 separation method Methods 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- 238000000967 suction filtration Methods 0.000 claims description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 4
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 239000010865 sewage Substances 0.000 claims description 4
- 239000010959 steel Substances 0.000 claims description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 claims description 3
- 239000004576 sand Substances 0.000 claims description 3
- 239000001569 carbon dioxide Substances 0.000 claims description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 2
- 238000005119 centrifugation Methods 0.000 claims description 2
- 239000001257 hydrogen Substances 0.000 claims description 2
- 229910052739 hydrogen Inorganic materials 0.000 claims description 2
- 125000004435 hydrogen atom Chemical class [H]* 0.000 claims description 2
- 150000002505 iron Chemical class 0.000 claims description 2
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 229910001385 heavy metal Inorganic materials 0.000 abstract description 15
- 229910052710 silicon Inorganic materials 0.000 abstract description 12
- 229910052782 aluminium Inorganic materials 0.000 abstract description 10
- 239000003795 chemical substances by application Substances 0.000 abstract description 7
- 230000008878 coupling Effects 0.000 abstract description 5
- 238000010168 coupling process Methods 0.000 abstract description 5
- 238000005859 coupling reaction Methods 0.000 abstract description 5
- 238000004056 waste incineration Methods 0.000 abstract description 5
- 230000008901 benefit Effects 0.000 abstract description 4
- 238000004064 recycling Methods 0.000 abstract description 4
- 239000002699 waste material Substances 0.000 abstract description 3
- 230000007613 environmental effect Effects 0.000 abstract description 2
- ODINCKMPIJJUCX-UHFFFAOYSA-N Calcium oxide Chemical compound [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 48
- 230000000052 comparative effect Effects 0.000 description 29
- 239000000203 mixture Substances 0.000 description 27
- 239000000047 product Substances 0.000 description 27
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 24
- 239000000292 calcium oxide Substances 0.000 description 24
- 235000012255 calcium oxide Nutrition 0.000 description 24
- 229910052681 coesite Inorganic materials 0.000 description 12
- 229910052906 cristobalite Inorganic materials 0.000 description 12
- 230000004907 flux Effects 0.000 description 12
- 239000000377 silicon dioxide Substances 0.000 description 12
- 229910052682 stishovite Inorganic materials 0.000 description 12
- 229910052905 tridymite Inorganic materials 0.000 description 12
- 238000001354 calcination Methods 0.000 description 10
- 230000008569 process Effects 0.000 description 10
- 238000002386 leaching Methods 0.000 description 9
- 238000010304 firing Methods 0.000 description 7
- 238000010998 test method Methods 0.000 description 6
- 239000011575 calcium Substances 0.000 description 5
- 238000005469 granulation Methods 0.000 description 5
- 230000003179 granulation Effects 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- HGUFODBRKLSHSI-UHFFFAOYSA-N 2,3,7,8-tetrachloro-dibenzo-p-dioxin Chemical compound O1C2=CC(Cl)=C(Cl)C=C2OC2=C1C=C(Cl)C(Cl)=C2 HGUFODBRKLSHSI-UHFFFAOYSA-N 0.000 description 4
- 238000010521 absorption reaction Methods 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 4
- 229910052500 inorganic mineral Inorganic materials 0.000 description 4
- 235000010755 mineral Nutrition 0.000 description 4
- 239000011707 mineral Substances 0.000 description 4
- 238000005245 sintering Methods 0.000 description 4
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 3
- 241000196324 Embryophyta Species 0.000 description 3
- 229910052791 calcium Inorganic materials 0.000 description 3
- 150000001804 chlorine Chemical class 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 230000003750 conditioning effect Effects 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000000465 moulding Methods 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 230000001988 toxicity Effects 0.000 description 3
- 231100000419 toxicity Toxicity 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 239000004567 concrete Substances 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 239000002920 hazardous waste Substances 0.000 description 2
- 238000001027 hydrothermal synthesis Methods 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 239000002910 solid waste Substances 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- 239000005995 Aluminium silicate Substances 0.000 description 1
- 239000002028 Biomass Substances 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 235000019738 Limestone Nutrition 0.000 description 1
- 241001122767 Theaceae Species 0.000 description 1
- 235000012211 aluminium silicate Nutrition 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- 229910001579 aluminosilicate mineral Inorganic materials 0.000 description 1
- 229910052586 apatite Inorganic materials 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- VTYYLEPIZMXCLO-UHFFFAOYSA-L calcium carbonate Substances [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 1
- 229910000019 calcium carbonate Inorganic materials 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000006298 dechlorination reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000007327 hydrogenolysis reaction Methods 0.000 description 1
- 230000003301 hydrolyzing effect Effects 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- NLYAJNPCOHFWQQ-UHFFFAOYSA-N kaolin Chemical compound O.O.O=[Al]O[Si](=O)O[Si](=O)O[Al]=O NLYAJNPCOHFWQQ-UHFFFAOYSA-N 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000005453 pelletization Methods 0.000 description 1
- VSIIXMUUUJUKCM-UHFFFAOYSA-D pentacalcium;fluoride;triphosphate Chemical compound [F-].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O VSIIXMUUUJUKCM-UHFFFAOYSA-D 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000009270 solid waste treatment Methods 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- 238000007158 vacuum pyrolysis Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/60—Production of ceramic materials or ceramic elements, e.g. substitution of clay or shale by alternative raw materials, e.g. ashes
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- Processing Of Solid Wastes (AREA)
Abstract
The invention provides ceramsite fired by using household garbage incineration fly ash and a preparation method and application thereof. By performing hydrothermal coupling pyrolysis treatment on the fly ash and the sludge, the content of soluble chlorine in a fly ash treatment product is greatly reduced, and the requirement of further recycling is met; the sludge is used as a regulator of Si, Al and Fe components, and provides necessary framework substances and pore-forming agents for the preparation process of the ceramsite by the waste incineration fly ash, so that the waste incineration fly ash is assisted to be sintered; the prepared ceramsite has good performance, and the high-strength building ceramsite with the density grade of 900-1200 can be prepared under the optimal condition; harmful heavy metals contained in the waste incineration fly ash and the sludge are effectively immobilized and stabilized. The invention implements the concept of treating waste by waste, realizes the common consumption of incineration fly ash and sludge, and has environmental benefit and economic benefit.
Description
Technical Field
The invention relates to the technical field of solid waste treatment, in particular to a fly ash fired ceramsite and a preparation method and application thereof.
Background
The fly ash from incineration of household garbage is a dangerous waste inevitably generated in the process of incineration of garbage. In the past decade, the domestic garbage production and the number of incineration plants in China are increased sharply, and the annual output of domestic garbage incineration fly ash is estimated to reach 900-1000 million tons in 2020. At present, the main treatment mode of incineration fly ash in China is landfill after cement solidification, but the mode has the defects of land resource occupation, low resource utilization rate and secondary environmental pollution, and under the condition that the output of the incineration fly ash is increased explosively, the development of non-landfill fly ash harmless and recycling technology is urgently needed.
CN106424077B discloses a method for treating incineration fly ash by using sludge. The method mixes the incineration fly ash and the sludge, and treats the incineration fly ash and the sludge through a hydrothermal coupling pyrolysis synergistic process, so as to achieve the purposes of dissolving and removing chlorine salt in the fly ash, hydrolyzing and detoxifying dioxin, and solidifying and stabilizing heavy metals. The fly ash and the inorganic components of the sludge act synergistically, so that the heavy metal is stabilized by generating aluminosilicate or zeolite-like substances, and the hydrothermal degradation of dioxin can be catalyzed to a certain extent; the tea residue biomass is added before pyrolysis, the solidification efficiency of heavy metal in pyrolysis is further enhanced, the leaching toxicity of the heavy metal in the obtained pyrolysis residue meets the GB5015.3-2007 standard, and the obtained pyrolysis residue can be used as common solid waste for landfill or used as an inorganic material for resource utilization. However, the problem of recycling the residue formed by co-hydrothermal and pyrolysis of fly ash and sludge, which are end-treatment products of the method, is not solved. The last kilometer is used after the end product is used, and the method has great significance for the landing popularization of the technology.
Because the incineration fly ash contains Si, Al, Ca, Fe, Na, K and other components, the components are similar to the components of the ceramic matrix raw material, and the preparation of the ceramsite by utilizing the incineration fly ash becomes one of the ways of recycling the incineration fly ash. The used incineration fly ash is mainly original incineration fly ash or incineration fly ash pretreated by water washing and leaching. For example, CN113213191A discloses a method for preparing ceramsite by using fly ash from waste incineration and the prepared ceramsite. The method takes waste incineration fly ash as a raw material, and prepares the ceramsite with excellent performance and standard harmful substance content by adding limestone, clay, fly ash, sludge and other high-silicon substances, regulating and controlling the proportion of main components of the ceramic preparation raw material, pelletizing, drying and roasting at high temperature. CN113336526A discloses a method for preparing ceramsite by pretreating incineration fly ash with chromium-containing wastewater in the steel industry. The method utilizes the once precipitated chromium-containing wastewater in the steel industry to wash and dissolve soluble chloride in the incineration fly ash for multiple times, and the washed chromium-containing fly ash mixed sludge is sintered to prepare the ceramsite.
At present, no patent related to the preparation of ceramsite by taking residues formed by hydrothermal and pyrolysis of incineration fly ash and sludge as raw materials exists. CN106007776B discloses a method and a device for preparing ceramsite by sludge pyrolytic biochar, wherein the method is used for mixing and granulating the sludge biochar with high-silicon auxiliary materials such as kaolin, quicklime or fly ash and the like to prepare the ceramsite applicable to the field of water treatment or building materials. However, due to the difference in raw materials and pretreatment methods, the properties of residues formed by hydrothermal and pyrolysis of incineration fly ash and sludge are different from those of sludge biochar and also different from the simple combination of sludge biochar and incineration fly ash. Therefore, the existing method is not suitable for incinerating the residues formed by co-hydrothermal and pyrolysis of fly ash and sludge.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a fly ash fired ceramsite and a preparation method and application thereof.
In a first aspect, the invention provides a fly ash fired ceramsite, and the preparation raw materials of the ceramsite comprise incineration fly ash and sludge.
As a specific embodiment of the present invention, the fly ash includes fly ash obtained by burning fly ash and/or household garbage; preferably, the content of soluble Cl in the fly ash is less than 30 wt%, and the content of CaO in the fly ash is 30-50 wt%.
As a specific embodiment of the present invention, the sludge is municipal sludge, preferably including at least one of sewage treatment plant sludge, water supply plant sludge, river dredging sludge, or drain pipe sludge; preferably, the sludge takes dry basis mass ratio as a reference, and SiO in the sludge is2Content (wt.)>20wt％，Al2O3Content (wt.)>10wt％，Fe2O3The content is 0.1 to 20 wt%.
In the present invention, for example, CaO, SiO2、Al2O3、Fe2O3The oxides do not mean that the raw materials involved or the raw materials necessarily contain the oxides, but represent the chemical composition of the materials in the form of oxides. In other words, in the present invention, the contents of Ca, Si, Al, Fe and the like are in terms of oxides.
As a specific embodiment of the present invention, Fe in the dry-based sludge2O3Content (wt.)<When the content is 10 wt%, the raw materials for preparing the ceramsite also comprise auxiliary materials. The auxiliary material is preferably a high-iron material, and the amount of the auxiliary material is enough to convert Fe based on the total amount of the auxiliary material and the mixed raw material2O3The content of (a) is adjusted to 10-20 wt%; the high-iron substance comprises at least one of sludge of an iron and steel plant, iron powder and iron salt.
As a specific embodiment of the present invention, Fe in sludge is used2O3When the content is more than or equal to 10 wt%, the addition of high-iron substances is not required. In particular, in some embodiments, Fe in the sludge2O3The content is more than or equal to 10 wt%, and high-iron substances are not added; in yet other embodiments, the Fe in the sludge2O3Content (wt.)<10 wt%, and the ceramsite preparation raw material also comprises a high-iron substance for improving Fe2O3But Fe2O3The content is less than or equal to 20wt percent.
As a specific embodiment of the invention, the sludge can be primary dehydrated activated sludge of an urban sewage treatment plant, and the water content is about 10-90 wt%. Preferably, the sludge is dewatered to obtain dry-based sludgeSiO2Content (wt.)>20wt％，Al2O3Content (wt.)>10wt％，Fe2O3The content is 10-20 wt%.
As a specific implementation mode of the invention, the sludge in the invention needs to have higher Si and Al contents, and can provide necessary framework substances and pore-forming agents for the fly ash incineration sintered ceramsite, so as to regulate and control the proportion of main components of the raw materials for preparing the ceramsite, thereby assisting the fly ash in sintering and preparing the ceramsite. On one hand, the low Si and Al contents are not beneficial to generating high-strength structures such as a glass phase and aluminosilicate minerals, and the strength of the ceramsite is reduced; on the other hand, the Fe element in the mixed raw materials is subjected to pretreatment and granulation steps, most of the Fe element exists in the form of Fe oxide>The gas can be dissociated and released at the high temperature of 1200 ℃, which is beneficial to creating a pore structure in the ceramsite, thereby reducing the density of the ceramsite and further obtaining a high-strength and light-weight ceramsite product. In addition, fluxing agent (K) required for preparing ceramsite2O、Na2O, MgO and CaO) component mainly derived from fly ash itself, excessive K2O、Na2O, MgO and CaO cause the sintering temperature range to be narrow, and the difficulty of sintering condition regulation is increased.
In a second aspect, the invention provides a preparation method of the ceramsite, which comprises the following steps:
s1: adding water into fly ash, sludge and optional auxiliary materials, and stirring to obtain mixed slurry;
s2: carrying out hydrothermal treatment on the mixed slurry to obtain a co-hydrothermal treatment product;
s3: carrying out solid-liquid separation on the co-hydrothermal treatment product, such as suction filtration or centrifugation, to obtain a co-hydrothermal mud cake;
s4: drying the co-hydrothermal mud cake, crushing, grinding and sieving to obtain co-hydrothermal solid-phase powder;
s5: pyrolyzing the hydrothermal solid-phase powder in an inert atmosphere to obtain pyrolysis residue;
s6: grinding and sieving the pyrolysis residue, adding water for humidifying and granulating to obtain raw material balls;
s7: and drying, roasting and cooling the raw material balls to obtain a ceramsite product.
In the step S1, the mass ratio of the fly ash to the sludge is 1 (4-10) on the basis of the mass ratio of the sludge on a dry basis.
As a specific embodiment of the invention, the main component contents of the mixed slurry are as follows on the basis of dry basis weight: SiO 22：20～60wt％，Al2O3：10～25wt％，Fe2O3:10 to 20 wt%. The specific adding proportion of the auxiliary materials can be adjusted according to the types of the auxiliary materials and the performance of the ceramsite.
The liquid-solid mass ratio in the obtained mixed slurry is not less than 4: 1.
The original fly ash is powdery and is directly used after being dried, so that the particle size of the fly ash is the intrinsic particle size; the sludge is primary dewatered sludge and is directly used without drying.
In a specific embodiment of the present invention, in the step S2, the hydrothermal treatment temperature is 110 to 240 ℃, and the hydrothermal treatment time is 30 to 60 min.
As a specific embodiment of the present invention, in the step S4, the soluble chlorine content of the hydrothermal solid phase powder can be calculated by the following formulas 1 and 2:
in the formulas 1 and 2, x and y respectively represent the dry basis mass ratio of the sludge to the fly ash raw material;
cSand cAThe content of soluble chlorine in the sludge and the fly ash is respectively as follows: wt%;
L/S is the liquid-solid ratio;
mris the dry mass of the sludge and fly ash blending raw material, the unit is: kg;
clis waterHot solid phase soluble Cl content, unit: wt%;
ωcakethe water content of the hydrothermal mud cake is shown as unit: wt%.
In a specific embodiment of the present invention, the grinding is performed to 100 to 200 mesh.
It should be noted that, according to the standard limit of HJ 1134-: the soluble chlorine content of the fly ash treatment product is not more than 2 wt%, preferably not more than 1 wt%.
As a specific embodiment of the present invention, in the present invention, chlorine salt removal is directly related to whether the pyrolysis residue satisfies the condition for resource utilization. Because excessive chlorine affects the safety and stability of the material treatment process and damages the structure and performance of the product, the country has established strict control standards for the chlorine content of the fly ash treatment product. In the hydrothermal coupling pyrolysis pretreatment process, the hydrothermal stage is a key dechlorination step, so that the co-hydrothermal solid-phase powder with the soluble chlorine content meeting the standard is a necessary premise for ensuring the chlorine content of the pyrolysis residue to reach the standard. In view of this, the present invention develops a formula that can be used to estimate the soluble chlorine content of co-hydrothermal solid-phase powders. On the one hand, this formula reveals hydrothermal process parameters such as: the mass ratio of fly ash to sludge, the hydrothermal liquid-solid ratio and the like are in internal relation with the content of soluble chlorine in the co-hydrothermal solid phase, the content of the soluble chlorine in the co-hydrothermal solid phase can be directly calculated by simply measuring indexes such as the water content of a hydrothermal mud cake and combining with the properties of raw materials, and the calculated value and the measured value show excellent fitting effect, as shown in fig. 5 (including but not limited to the embodiment), so that large-batch chemical measurement can be avoided; on the other hand, under the condition that the target content of the co-hydrothermal solid phase soluble chlorine and the mass ratio of the fly ash to the sludge are preset, the co-hydrothermal solid phase with the chlorine reaching the standard can be easily obtained by adopting the liquid-solid ratio not lower than the liquid-solid ratio calculated by the formula, so that the cost consumed by adjusting process parameters is saved.
As a specific embodiment of the present invention, in step S5, the inert atmosphere is any one of nitrogen, carbon monoxide, carbon dioxide, hydrogen, or vacuum pyrolysis;
the pyrolysis treatment temperature is 700-100 ℃, and the pyrolysis treatment time is 50-60 min;
the soluble chlorine content in the obtained pyrolysis residue is <2 wt%;
k in the obtained pyrolysis residue2O、Na2O, MgO sum of CaO content<25wt％。
As a specific embodiment of the invention, in the invention, the incineration fly ash is firstly pretreated by a sludge-assisted hydrothermal coupling pyrolysis process. On one hand, the content of soluble salt in the treated product of the fly ash is greatly removed, heavy metal in the fly ash is primarily removed and fixed and stabilized, dioxin substances are eliminated to a certain degree, and the negative harm of harmful substances to the subsequent resource process and products as well as the environment and human bodies is reduced; on the other hand, the co-hydrothermal-pyrolysis treatment of the fly ash and the sludge can obviously change the chemical composition of the treatment product, and the fly ash contains overhigh content of soluble chlorine salts such as NaCl, KCl, CaCl (OH) and the like and Ca (OH)2、CaCO3When the calcium-containing minerals are dissolved and removed, the Cl and fluxing agent contents in the raw materials are reduced, and the property of the fly ash used as the raw material for preparing the ceramsite is further improved.
In the step S6, the mass ratio of water to pyrolysis residue in the water-added granulation is (1.2-1.5): 1; the particle size of the raw material balls is 5-1 mm; the granulation mode can be manual granulation or mechanical disc granulation.
As a specific embodiment of the invention, in the step S7, the drying is low-temperature drying, and the drying temperature is 10 to 110 ℃; the roasting temperature is 1100-1300 ℃, and the roasting time is 5-30 min; preferably, the roasting temperature is 1150-1250 ℃, and the roasting time is 10-20 min.
As a preferred technical scheme, in the invention, the raw material ball is roasted for 10-20 min at the roasting temperature of 1150-1250 ℃ to obtain the ceramsite product with indexes such as compressive strength, water absorption and density meeting the standard. If the roasting temperature is too low, the ceramic components cannot be effectively melted, no enough liquid phase is generated in the system, and the particles are difficult to be tightly combined, so that the ceramic particle strength is low and the water absorption rate is high; if the roasting temperature is too high, the raw material components are excessively molten, so that the ceramsite cannot keep a fixed shape, and the phenomenon of collapse is caused; in addition, the energy consumption and the cost for firing the ceramsite at an excessively high temperature are high, and the obtained ceramsite product has no commercial application value. On the other hand, if the calcination time is too short, the calcination is not sufficient, and if the calcination time is too long, the energy is wasted.
The raw materials in the present invention may be obtained by sampling themselves or may be obtained commercially, and the present invention is not particularly limited thereto.
In a third aspect, the invention provides an application of the ceramsite in the field of building materials.
As a specific embodiment of the invention, the ceramsite is used as the ceramsite light aggregate and applied to the field of building materials.
As a specific embodiment of the invention, the ceramsite can be used as artificial light aggregate to replace natural sand and broken stone for preparing ceramsite concrete or ceramsite hollow blocks, and is applied to the fields of roads, house walls, engineering construction and the like.
Compared with the prior art, the invention has the beneficial effects that:
1. compared with the method that the incineration fly ash and the sludge are directly used as raw materials, the method effectively reduces the negative influence of high-concentration chloride in the fly ash on the performance of equipment and products, improves the utilization rate of the incineration fly ash, changes the chemical component content and proportion of the obtained ceramic raw material through the processing treatment of hydrothermal coupling pyrolysis of the raw materials, and greatly improves the characteristic of the fly ash as the sintered ceramsite preparation raw material.
2. The method prepares the ceramsite by roasting the pyrolysis residue, wherein the high-temperature roasting process is favorable for thoroughly decomposing and destroying toxic and harmful organic matters such as dioxin and the like; the pyrolysis residue contains apatite minerals (generated by P element from sludge and Ca mineral mainly from fly ash under pyrolysis conditions) beneficial to heavy metal stabilization besides Si and Al, and can effectively combine heavy metals, reduce volatilization of the heavy metals in the sintering process, and enable the heavy metals to be solidified in a glass phase or minerals in a stable form, thereby reducing emission of harmful waste gas.
3. The pyrolysis residue prepared in the core link of the invention has low volatile content, so the preparation of the ceramsite can save the preheating link, save energy and reduce emission; the invention has no residual residue, can simultaneously realize the final consumption of incineration fly ash and municipal sludge, and fully utilizes solid waste; the method is simple and easy to implement, and the prepared high-strength ceramsite can be applied to the field of building materials and has good environmental benefit and economic benefit.
Drawings
FIG. 1 is a photograph showing the appearance of the pyrolysis residue obtained in step S5 in example 2 of the present invention;
FIG. 2 is a photograph showing the appearance of the ceramsite product prepared in example 2;
FIG. 3 is a photograph showing the appearance of the ceramsite product prepared in example 3;
FIG. 4 is a photograph showing the appearance of the ceramsite product prepared in example 4 of the present invention;
FIG. 5 is a linear fit of calculated and actually measured soluble chlorine content values for the hydrothermal solid phase powder of the invention.
Detailed Description
The present invention is further illustrated by the following examples, which are not to be construed as limiting the invention in any way.
In the embodiments of the present invention, the adopted production standard HJ1134 and 2020 standard limit define: the soluble chlorine content of the fly ash treatment product is not more than 2 wt%, preferably not more than 1 wt%.
In the embodiments of the invention, the fly ash is fly ash powder left by burning domestic garbage of a certain city, the main components of the fly ash powder are that Cl is 24.75 wt%, CaO is 44.72 wt%, and (K)2O+Na2O + MgO + CaO) was 61.25 wt%.
In each embodiment of the invention, the sludge is sludge of a sewage treatment plant in a certain market, the water content is 79.34 wt%, and the dry basis main component content is SiO224.06 wt%, Al2O316.61 wt% Fe2O3It was 17.91 wt%.
Due to the fact thatFe of the sludge2O3The content is within the required range, so that no additional high iron substance is required to be added.
In each embodiment of the present invention, the specific device information used is as follows:
FCF-2L high-temperature high-pressure hydrothermal reaction kettle manufactured by Zhengzhou Boyan instruments Co., Ltd; a self-developed equipment pyrolysis carbonization furnace manufactured by Beijing Funsen electric furnace Co., Ltd; QSH-1700M muffle furnace manufactured by Shanghai Quanshuo electric Co.
Example 1
The embodiment provides a fly ash fired ceramsite and a preparation method thereof, and the specific details are as follows:
s1: uniformly stirring and mixing incineration fly ash and wet sludge according to the dry-basis mass ratio of 1:4, and adding water to adjust the liquid-solid ratio to 5:1 to obtain mixed slurry;
s2: carrying out hydro-thermal treatment on the mixed slurry at 110 ℃ for 60min to obtain a co-hydro-thermal product;
s3: carrying out solid-liquid separation on the obtained hydrothermal product in a suction filtration mode to obtain a hydrothermal mud cake;
s4: drying, crushing and grinding the co-hydrothermal mud cake and sieving the co-hydrothermal mud cake with a 100-mesh sieve to obtain co-hydrothermal solid-phase powder;
s5: pyrolyzing the hydrothermal solid-phase powder at 100 ℃ in a nitrogen atmosphere for 60min to obtain pyrolysis residue (residue 1);
s6: grinding the pyrolysis residues, sieving the ground pyrolysis residues with a 100-mesh sieve, adding water with the mass of 1.4 times of the residues for conditioning, and manually twisting the residues into raw material balls with the diameter of 5-1 mm;
s7: and drying the raw material balls in an oven, then feeding the dried raw material balls into a high-temperature furnace, roasting at the temperature of 1275 ℃ for 10min, and cooling along with the furnace to obtain a ceramsite product.
In example 1, the main chemical composition (expressed in oxide form) of fly ash, sludge and residue 1 is shown in table 1:
TABLE 1 chemical composition of sludge and residue 1 (wt%)
| Composition (I) | SiO2 | Al2O3 | Na2O | MgO | K2O | CaO | Fe2O3 | P2O5 |
| Fly ash | 3.51 | 0.11 | 9.10 | 1.09 | 5.64 | 44.72 | 0.19 | 0.30 |
| Sludge treatment | 24.06 | 16.21 | 0.11 | 1.41 | 1.41 | 3.42 | 17.91 | 10.20 |
| Residue 1 | 25.24 | 20.11 | 1.31 | 2.39 | 1.30 | 16.21 | 12.51 | 10.67 |
The fly ash and sludge mixed raw material obtained in step S1 of example 1 had the following main component contents: SiO 22：19.95wt％，Al2O3：13.19wt％，Fe2O3：14.51wt％。
The calculated value of the soluble chlorine content of the co-hydrothermal solid phase powder obtained in step S4 of example 1 was 2.10 wt%, which is close to the observed value of 2.00 wt%, indicating a good matching degree between the two.
The soluble chlorine content in the residue 1 obtained in step S5 of example 1 was 1.37 wt%, and satisfied the standard limit of HJ 1134-2020; flux (K) in the obtained residue 12O+Na2O + MgO + CaO) component content of 21.21 wt%, SiO2、Al2O3The contents were 25.24 wt% and 20.11 wt%, respectively. Therefore, compared with the incineration fly ash raw material, the content of chlorine and fluxing agent components in the residue 1 is greatly reduced, the content of Si and Al is greatly improved, and the property of fly ash used as the raw material for preparing ceramsite is obviously improved.
Example 2
The embodiment provides a ceramsite fired by using household garbage incineration fly ash and a preparation method thereof, and the specific details are as follows:
the difference between this example and example 1 is that the calcination temperature is 1250 deg.C, the calcination time is 20min, and other materials, conditions, steps, etc. are the same as example 1.
In example 2, the main chemical composition (expressed in oxide form) of fly ash, sludge and residue 1 is shown in table 2:
TABLE 2 chemical composition of sludge and residue 1 (wt%)
| Composition (I) | SiO2 | Al2O3 | Na2O | MgO | K2O | CaO | Fe2O3 | P2O5 |
| Fly ash | 3.51 | 0.11 | 9.10 | 1.09 | 5.64 | 44.72 | 0.19 | 0.30 |
| Sludge treatment | 24.06 | 16.21 | 0.11 | 1.41 | 1.41 | 3.42 | 17.91 | 10.20 |
| Residue 1 | 25.24 | 20.11 | 1.31 | 2.39 | 1.30 | 16.21 | 12.51 | 10.67 |
The fly ash and sludge mixed raw material obtained in step S1 of example 2 had the following main component contents: SiO 22：19.95wt％，Al2O3：13.19wt％，Fe2O3：14.51wt％。
The soluble chlorine content in the residue 1 obtained in step S5 of example 2 was 1.37 wt%, and satisfied the standard limit of HJ 1134-2020;
flux (K) in the obtained residue 12O+Na2O + MgO + CaO) component content was 21.21 wt%.
Example 3
The embodiment provides a ceramsite fired by using household garbage incineration fly ash and a preparation method thereof, and the specific details are as follows:
the difference between this example and example 1 is that the calcination temperature is 1200 deg.C, the calcination time is 20min, and other materials, conditions, steps, etc. are the same as example 1.
In example 3, the main chemical composition (expressed in oxide form) of fly ash, sludge and residue 1 is shown in table 3:
TABLE 3 chemical composition of sludge and residue 1 (wt%)
| Composition (I) | SiO2 | Al2O3 | Na2O | MgO | K2O | CaO | Fe2O3 | P2O5 |
| Fly ash | 3.51 | 0.11 | 9.10 | 1.09 | 5.64 | 44.72 | 0.19 | 0.30 |
| Sludge treatment | 24.06 | 16.21 | 0.11 | 1.41 | 1.41 | 3.42 | 17.91 | 10.20 |
| Residue 1 | 25.24 | 20.11 | 1.31 | 2.39 | 1.30 | 16.21 | 12.51 | 10.67 |
The fly ash and sludge mixed raw material obtained in step S1 of example 3 has the following main component contents: SiO 22：19.95wt％，Al2O3：13.19wt％，Fe2O3：14.51wt％。
The soluble chlorine content in the residue 1 obtained in step S5 of example 3 was 1.37 wt%, and satisfied the standard limit of HJ 1134-2020;
flux (K) in the obtained residue 12O+Na2O + MgO + CaO) component content was 21.21 wt%.
Example 4
The embodiment provides a ceramsite fired by using household garbage incineration fly ash and a preparation method thereof, and the specific details are as follows:
the present example is different from example 1 only in that the calcination temperature is 1150 ℃ and the calcination time is 30min, and other materials, conditions, steps and the like are the same as example 1.
In example 4, the main chemical composition (expressed in oxide form) of fly ash, sludge and residue 1 is shown in table 4:
TABLE 4 chemical composition of sludge and residue 1 (wt%)
| Composition (I) | SiO2 | Al2O3 | Na2O | MgO | K2O | CaO | Fe2O3 | P2O5 |
| Fly ash | 3.51 | 0.11 | 9.10 | 1.09 | 5.64 | 44.72 | 0.19 | 0.30 |
| Sludge treatment | 24.06 | 16.21 | 0.11 | 1.41 | 1.41 | 3.42 | 17.91 | 10.20 |
| Residue 1 | 25.24 | 20.11 | 1.31 | 2.39 | 1.30 | 16.21 | 12.51 | 10.67 |
The fly ash and sludge mixed raw material obtained in step S1 of example 4 had the following main component contents: SiO 22：19.95wt％，Al2O3：13.19wt％，Fe2O3：14.51wt％。
The soluble chlorine content in the residue 1 obtained in step S5 of example 4 was 1.37 wt%, and satisfied the standard limit of HJ 1134-2020;
flux (K) in the obtained residue 12O+Na2O + MgO + CaO) component content was 21.21 wt%.
Example 5
The embodiment provides a fly ash fired ceramsite and a preparation method thereof, and the specific details are as follows:
s1: uniformly stirring and mixing incineration fly ash and wet sludge according to the dry-basis mass ratio of 1:10, and adding water to adjust the liquid-solid ratio to 4:1 to obtain mixed slurry;
s2: carrying out hydro-thermal treatment on the mixed slurry at 110 ℃ for 60min to obtain a co-hydro-thermal product;
s3: carrying out solid-liquid separation on the obtained hydrothermal product in a suction filtration mode to obtain a hydrothermal mud cake;
s4: drying, crushing and grinding the co-hydrothermal mud cake and sieving the co-hydrothermal mud cake with a 100-mesh sieve to obtain co-hydrothermal solid-phase powder;
s5: pyrolyzing the hydrothermal solid-phase powder at 700 ℃ in a nitrogen atmosphere for 60min to obtain pyrolysis residue (residue 2);
s6: grinding the pyrolysis residues, sieving the ground pyrolysis residues with a 100-mesh sieve, adding water with the mass of 1.4 times of the residues for conditioning, and manually twisting the residues into raw material balls with the diameter of 5-1 mm;
s7: and drying the raw material balls in an oven, then feeding the dried raw material balls into a high-temperature furnace to be roasted at 1250 ℃, wherein the roasting time is 10min, and cooling the raw material balls along with the furnace to obtain a ceramsite product.
In example 5, the main chemical composition (expressed in oxide form) of fly ash, sludge and residue 2 is shown in table 5:
TABLE 5 chemical composition of sludge and residue 2 (wt%)
The fly ash and sludge mixed raw material obtained in step S1 of example 5 has the following main component contents: SiO 22：22.19wt％，Al2O3：14.17wt％，Fe2O3：16.36wt％。
The calculated value of the soluble chlorine content of the co-hydrothermal solid phase powder obtained in step S4 of example 5 was 1.31 wt%, which is close to the observed value of 1.31 wt%, indicating that the two have a better matching degree.
The soluble chlorine content in the residue 2 obtained in step S5 of example 5 was 1.03 wt%, and satisfied the HJ1134-2020 standard limit value; flux (K) in the obtained residue 22O+Na2O + MgO + CaO) component content of 9.63 wt%, SiO2、Al2O3The contents were 21.11 wt% and 19.72 wt%, respectively. Therefore, compared with the incineration fly ash raw material, the Cl and fluxing agent content of the residue 2 is greatly reduced, the Si and Al content is greatly improved, and the property of the fly ash used as the raw material for preparing the ceramsite is obviously improved.
Comparative example 1
The comparative example provides a fly ash fired ceramsite and a preparation method thereof, and the specific details are as follows:
s1: uniformly stirring and mixing incineration fly ash and wet sludge according to the dry-basis mass ratio of 3:4, and adding water to adjust the liquid-solid ratio to 10:1 to obtain mixed slurry;
s2: carrying out hydro-thermal treatment on the mixed slurry at 110 ℃ for 60min to obtain a co-hydro-thermal product;
s3: carrying out solid-liquid separation on the obtained hydrothermal product in a suction filtration mode to obtain a hydrothermal mud cake;
s4: drying, crushing and grinding the co-hydrothermal mud cake and sieving the co-hydrothermal mud cake with a 100-mesh sieve to obtain co-hydrothermal solid-phase powder;
s5: pyrolyzing the co-hydrothermal solid-phase powder at 100 ℃ for 60min in a carbon monoxide atmosphere to obtain pyrolysis residue (residue 3);
s6: grinding the pyrolysis residues, sieving the ground pyrolysis residues with a 100-mesh sieve, adding water with the mass of 1.45 times of the residues for conditioning, and manually twisting the residues into raw material balls with the diameter of 5-1 mm;
s7: and drying the raw material balls in an oven, then feeding the dried raw material balls into a high-temperature furnace to be roasted at 1150 ℃ for 30min, and cooling the raw material balls along with the furnace to obtain a ceramsite product.
In comparative example 1, the main chemical composition (expressed in oxide form) of fly ash, sludge and residue 3 is shown in table 6:
TABLE 6 chemical composition of sludge and residue 3 (wt%)
The fly ash and sludge mixed raw material obtained in step S1 of comparative example 1 had the following main component contents: SiO 22：15.25wt％，Al2O3：9.65wt％，Fe2O3：10.62wt％。
The calculated value of the soluble chlorine content of the hydrothermal solid phase powder of comparative example 1, step S4, was 1.95 wt%, which is close to the observed value of 1.92 wt%, indicating a good degree of matching between the two.
The soluble chlorine content in the residue 3 obtained in step S5 of comparative example 1 was 1.12 wt%, satisfying the HJ1134-2020 standard limit; flux (K) in the obtained residue 32O+Na2O + MgO + CaO) component content of 37.19 wt%, SiO2、Al2O3The contents were 19.51 wt% and 13.91 wt%, respectively. Therefore, compared with the incineration fly ash raw material, the Cl and fluxing agent content of the residue 3 is reduced, the Si and Al content is improved, and the property of preparing the ceramsite by taking the fly ash as the raw material is improved to a certain extent.
Comparative example 2
A ceramsite prepared by burning fly ash from incineration of household garbage is different from comparative example 1 only in that the adopted roasting temperature is 1225 ℃, the roasting time is 20min, and other materials, conditions, steps and the like are the same as those in example 1.
In comparative example 2, the main chemical composition (expressed in oxide form) of fly ash, sludge and residue 3 is shown in table 7:
TABLE 7 chemical composition of sludge and residue 3 (wt%)
| Composition (I) | SiO2 | Al2O3 | Na2O | MgO | K2O | CaO | Fe2O3 | P2O5 |
| Fly ash | 3.51 | 0.11 | 9.10 | 1.09 | 5.64 | 44.72 | 0.19 | 0.30 |
| Sludge treatment | 24.06 | 16.21 | 0.11 | 1.41 | 1.41 | 3.42 | 17.91 | 10.20 |
| Residue 3 | 19.51 | 13.91 | 0.62 | 2.93 | 1.21 | 33.06 | 11.33 | 6.17 |
The fly ash and sludge mixed raw material obtained in step S1 of comparative example 2 had the following main component contents: SiO 22：15.25wt％，Al2O3：9.65wt％，Fe2O3：10.62wt％。
The soluble chlorine content in the residue 3 obtained in step S5 of comparative example 2 was 1.12 wt%, satisfying the HJ1134-2020 standard limit;
flux (K) in the obtained residue 32O+Na2O + MgO + CaO) component content was 37.19 wt%.
Comparative example 3
A ceramsite produced by firing fly ash from incineration of household garbage is different from comparative example 1 only in that the firing temperature is 1250 ℃ and the firing time is 20min, and other materials, conditions, steps and the like are the same as those of example 1.
In comparative example 3, the main chemical composition (expressed in oxide form) of fly ash, sludge and residue 3 is shown in table 1:
TABLE 1 chemical composition of sludge and residue 3 (wt%)
| Composition (I) | SiO2 | Al2O3 | Na2O | MgO | K2O | CaO | Fe2O3 | P2O5 |
| Fly ash | 3.51 | 0.11 | 9.10 | 1.09 | 5.64 | 44.72 | 0.19 | 0.30 |
| Sludge treatment | 24.06 | 16.21 | 0.11 | 1.41 | 1.41 | 3.42 | 17.91 | 10.20 |
| Residue 3 | 19.51 | 13.91 | 0.62 | 2.93 | 1.21 | 33.06 | 11.33 | 6.17 |
The fly ash and sludge mixed raw material obtained in step S1 of comparative example 3 had the following main component contents: SiO 22：15.25wt％，Al2O3：9.65wt％，Fe2O3：10.62wt％。
The soluble chlorine content in the residue 3 obtained in step S5 of comparative example 3 was 1.12 wt%, satisfying the HJ1134-2020 standard limit;
flux (K) in the obtained residue 32O+Na2O + MgO + CaO) component content was 37.19 wt%.
Comparative example 4
This comparative example provides a ceramsite produced by firing fly ash from incineration of household garbage and a method for producing the same, which is different from example 1 only in that calcination is not performed, and other materials, conditions, steps, and the like are the same as those of example 1.
In comparative example 4, the main chemical composition (expressed in oxide form) of fly ash, sludge and residue 1 is shown in table 9:
TABLE 9 chemical composition of sludge and residue 1 (wt%)
| Composition (I) | SiO2 | Al2O3 | Na2O | MgO | K2O | CaO | Fe2O3 | P2O5 |
| Fly ash | 3.51 | 0.11 | 9.10 | 1.09 | 5.64 | 44.72 | 0.19 | 0.30 |
| Sludge treatment | 24.06 | 16.21 | 0.11 | 1.41 | 1.41 | 3.42 | 17.91 | 10.20 |
| Residue 1 | 25.24 | 20.11 | 1.31 | 2.39 | 1.30 | 16.21 | 12.51 | 10.67 |
The fly ash and sludge mixed raw material obtained in step S1 of comparative example 4 had the following main component contents: SiO 22：19.95wt％，Al2O3：13.19wt％，Fe2O3：14.51wt％。
The soluble chlorine content in the residue 1 obtained in step S5 of comparative example 4 was 1.37 wt%, satisfying the HJ1134-2020 standard limit;
flux (K) in the obtained residue 12O+Na2O + MgO + CaO) component content was 21.21 wt%.
Test example
The test method comprises the following steps:
(1) appearance: visually observing the appearance of the prepared ceramsite;
(2) and (3) performance testing: the measurement of the bulk density and water absorption of the ceramsite refers to the national standard lightweight aggregate and the test method part 2: the lightweight aggregate test method (GB/T17431.2-2010); the compression strength is tested on a universal material electronic testing machine, and the value can be folded into 0.9 time of the cylinder compression strength;
(3) and (3) leaching test of ceramsite heavy metal gold: an acetic acid solution buffer method (HJ/T300-2007) method is adopted.
The ceramsite obtained in examples 1 to 5 and comparative examples 1 to 3 was tested according to the above test method, and the test results are shown in tables 9 and 10.
The molding conditions and performance test results of the ceramsite are shown in Table 10:
TABLE 10 measurement of the molding conditions and Properties of the ceramsite
From the data in table 10 it can be seen that:
the ceramsite obtained in the embodiments 2-5 has a good molding state, and the ceramsite can keep a good fixed shape; whereas example 1 and comparative example 3 underwent the occurrence of the collapse at 1275 c and 1250 c, respectively, because the flux component content (37.19 wt%) of the residue 3 was higher than the flux content (21.21 wt%) of the residue 1, and an excessively high flux content caused the decrease in the melting phase transition temperature of the ceramsite.
Further comparing example 2 with comparative example 3, and example 3 with comparative example 2, it can be seen that the ceramsite prepared from residue 1 (examples 2 and 3) has higher compressive strength than the ceramsite prepared from residue 3 (comparative examples 2 and 3) at the same or lower temperature, because the dry-basis mass ratio of fly ash and sludge in comparative examples 2 and 3 is 3:4, and the excessively high mass ratio of fly ash and sludge directly causes the content of Si and Al in the fly ash and sludge co-hydrothermal-pyrolysis residue as raw materials for preparing the ceramsite to be too low, thereby causing the compressive strength of the ceramsite to be reduced.
Further comparing examples 1-5 and comparative examples 1-3 with GB/T17431.1-2010 lightweight aggregate and test method part 1 thereof: the standard of light aggregate shows that the ceramsite obtained in the embodiments 2 to 3 and 5 meets the requirement of the high-strength ceramsite with the density grade of 900 to 1200, and can be used as the ceramsite light aggregate to be applied to the field of building materials.
The leaching concentrations of heavy metals of the preferred examples 2 to 5 and comparative example 1 are shown in table 11:
TABLE 11 heavy metal leaching of ceramsite (mg. L)-1)
From the data in table 11 it can be seen that:
the leaching concentration of each heavy metal in the ceramsite prepared by the method is far lower than GB5015.3-2007 'identification Standard for hazardous waste identification Standard for Leaching toxicity'.
In conclusion, the ceramsite prepared by the method disclosed by the invention is good in performance, and the compressive strength, the water absorption and the bulk density of the ceramsite accord with GB/T17431.1-2010 light aggregate and the test method part 1 thereof: the standard of light aggregate requires, and the heavy metal leaching of the ceramsite meets GB5015.3-2007 'identification standard for hazardous waste identification Standard for leaching toxicity identification Standard'. In the preparation process of the ceramsite, in order to obtain pyrolysis residues with components meeting the ceramic preparation conditions, the dry-basis mass ratio and the hydrothermal liquid-solid ratio of fly ash and sludge are key parameters and need to be respectively controlled within the ranges of 1 (4-10) and not less than 4: 1; in order to ensure that the soluble chlorine of the pyrolysis residue meets the requirements of HJ 1134-; the ceramic raw material with the main component within the control range can be used for firing the ceramsite light aggregate within the roasting temperature range of 1100-1300 ℃, and can be used for successfully firing high-strength building ceramsite with the density grade of 900-1200 under a further optimized condition, so that the ceramic raw material can be used for preparing ceramsite concrete or ceramsite hollow blocks and can be applied to the fields of roads, building walls, engineering construction and the like.
Any numerical value mentioned in this specification, if there is only a two unit interval between any lowest value and any highest value, includes all values from the lowest value to the highest value incremented by one unit at a time. For example, if it is stated that the amount of a component, or a value of a process variable such as temperature, pressure, time, etc., is 50 to 90, it is meant in this specification that values of 51 to 19, 52 to 11 … …, and 69 to 71, and 70 to 71, etc., are specifically enumerated. For non-integer values, units of 0.1, 0.01, 0.001, or 0.0001 may be considered as appropriate. These are only some specifically named examples. In a similar manner, all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be disclosed in this application.
It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.
Claims (12)
1. The ceramsite fired by the fly ash is characterized in that the preparation raw materials of the ceramsite comprise the fly ash and sludge.
2. The ceramsite according to claim 1, wherein the fly ash comprises fly ash obtained by burning fly ash and/or household garbage; preferably, the content of soluble Cl in the fly ash is less than 30 wt%, and the content of CaO is 30-50 wt%;
and/or the sludge is municipal sludge, preferably comprising at least one of sewage treatment plant sludge, water supply plant sludge, river channel dredging sludge or drain pipeline sludge; preferably, the sludge takes dry basis mass ratio as a reference, and SiO in the sludge is2Content (wt.)>20wt％，Al2O3Content (wt.)>10wt％，Fe2O3The content is 0.1-20 wt%;
and/or the mass ratio of the fly ash to the sludge is (4-10) on the basis of the mass ratio of dry basis to the mass ratio of the sludge.
3. Ceramsite according to claim 1 or 2, characterized in that Fe is contained in the dry sludge2O3Content (wt.)<When the content of the auxiliary materials is 10 wt%, the raw materials for preparing the ceramsite also comprise auxiliary materials, wherein the auxiliary materials are high-iron substances, and the amount of the auxiliary materials is enough to ensure that the auxiliary materials are added into the total amount of the mixed raw materials based on the auxiliary materialsFe2O3The content of (a) is adjusted to 10-20 wt%;
the high-iron substance is preferably at least one of sludge of an iron and steel plant, iron powder and iron salt.
4. The method for preparing ceramsite according to any one of claims 1-3, wherein the method comprises the following steps:
s1: adding water into fly ash, sludge and optional auxiliary materials, and stirring to obtain mixed slurry;
s2: carrying out hydrothermal treatment on the mixed slurry to obtain a co-hydrothermal treatment product;
s3: carrying out solid-liquid separation on the co-hydrothermal treatment product, such as suction filtration or centrifugation, to obtain a co-hydrothermal mud cake;
s4: drying the co-hydrothermal mud cake, crushing, grinding and sieving to obtain co-hydrothermal solid-phase powder;
s5: pyrolyzing the hydrothermal solid-phase powder in an inert atmosphere to obtain pyrolysis residue;
s6: grinding and sieving the pyrolysis residue, adding water for humidifying and granulating to obtain raw material balls;
s7: and drying, roasting and cooling the raw material balls to obtain a ceramsite product.
5. The preparation method according to claim 4, wherein in the step S1, the mass ratio of the fly ash to the sludge is 1 (4-10) on a dry basis; and/or
On the basis of dry basis mass, the main component content of the mixed slurry is as follows: SiO 22：20～60wt％，Al2O3：10～25wt％，Fe2O3：10～20wt％；
And/or the liquid-solid mass ratio in the obtained mixed slurry is not less than 4: 1.
6. The method according to claim 4 or 5, wherein in the step S2, the hydrothermal treatment temperature is 180 to 240 ℃ and the hydrothermal treatment time is 30 to 60 min.
7. The method according to any one of claims 4 to 6, wherein in step S4, the soluble chlorine content of the co-hydrothermal solid phase powder is calculated by formulas 1 and 2:
in the formulas 1 and 2, x and y respectively represent the dry basis mass ratio of the sludge to the fly ash raw material;
cSand cAThe content of soluble chlorine in the sludge and the fly ash is respectively as follows: wt%;
L/S is the liquid-solid ratio;
mris the dry mass of the sludge and fly ash blending raw material, the unit is: kg;
clis the content of soluble chlorine in hydrothermal solid phase, unit: wt%;
ωcakethe water content of the hydrothermal mud cake is shown as unit: wt%.
8. The method according to any one of claims 4 to 7, wherein in step S4, the co-hydrothermal solid-phase powder has a particle size of 100 to 200 mesh.
9. The method according to any one of claims 4 to 8, wherein in step S5, the inert atmosphere is any one of nitrogen, carbon monoxide, carbon dioxide, hydrogen, or vacuum; and/or
The pyrolysis treatment temperature is 700-800 ℃, and the pyrolysis treatment time is 50-60 min; and/or
The soluble chlorine content in the obtained pyrolysis residue is <2 wt%; and/or
The above-mentionedK in the pyrolysis residue obtained2O、Na2O, MgO sum of CaO content<25wt％。
10. The production method according to any one of claims 4 to 9, wherein in the step S6, in the humidifying with water and granulating, the mass ratio of water to pyrolysis residue is (1.2-1.5): 1; and/or
The particle size of the raw material balls is 5-8 mm.
11. The preparation method according to any one of claims 4 to 10, wherein in the step S7, the drying is low-temperature drying, and the drying temperature is 80-110 ℃; and/or
The roasting temperature is 1100-1300 ℃, and preferably 1150-1250 ℃; the roasting time is 5-30 min, preferably 10-20 min.
12. The use of the ceramic particles according to any one of claims 1 to 3 or the ceramic particles obtained by the preparation method according to any one of claims 4 to 11 in the field of building materials.
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