CN118389822A - Method for preparing cold-bonded pellets based on alkali-activated steel slag and obtained product - Google Patents
Method for preparing cold-bonded pellets based on alkali-activated steel slag and obtained product Download PDFInfo
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- 239000002893 slag Substances 0.000 title claims abstract description 181
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 175
- 239000010959 steel Substances 0.000 title claims abstract description 175
- 239000008188 pellet Substances 0.000 title claims abstract description 165
- 239000003513 alkali Substances 0.000 title claims abstract description 68
- 238000000034 method Methods 0.000 title claims abstract description 58
- 239000000428 dust Substances 0.000 claims abstract description 61
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 21
- 238000002156 mixing Methods 0.000 claims abstract description 20
- 239000002440 industrial waste Substances 0.000 claims abstract description 19
- 239000007789 gas Substances 0.000 claims abstract description 18
- 238000007596 consolidation process Methods 0.000 claims abstract description 15
- 238000000227 grinding Methods 0.000 claims abstract description 14
- 238000003825 pressing Methods 0.000 claims abstract description 13
- 238000001465 metallisation Methods 0.000 claims abstract description 5
- 238000012216 screening Methods 0.000 claims abstract description 3
- 238000005245 sintering Methods 0.000 claims description 43
- 239000002245 particle Substances 0.000 claims description 28
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 17
- 239000003546 flue gas Substances 0.000 claims description 17
- 239000000126 substance Substances 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 12
- 239000000203 mixture Substances 0.000 claims description 8
- 238000005554 pickling Methods 0.000 claims description 7
- 229910004742 Na2 O Inorganic materials 0.000 claims description 5
- 239000012535 impurity Substances 0.000 claims description 5
- 239000002253 acid Substances 0.000 claims description 4
- 230000008569 process Effects 0.000 abstract description 17
- 238000002360 preparation method Methods 0.000 abstract description 10
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 abstract description 3
- 229910052725 zinc Inorganic materials 0.000 abstract description 3
- 239000011701 zinc Substances 0.000 abstract description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 30
- 230000000694 effects Effects 0.000 description 21
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 20
- 238000001514 detection method Methods 0.000 description 18
- 230000000052 comparative effect Effects 0.000 description 16
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 description 10
- 235000019253 formic acid Nutrition 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 9
- 230000001276 controlling effect Effects 0.000 description 9
- 238000006703 hydration reaction Methods 0.000 description 9
- 239000011148 porous material Substances 0.000 description 8
- 239000002994 raw material Substances 0.000 description 8
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 7
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 6
- 230000005284 excitation Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 230000002378 acidificating effect Effects 0.000 description 5
- 239000013543 active substance Substances 0.000 description 5
- 239000011259 mixed solution Substances 0.000 description 5
- 238000011112 process operation Methods 0.000 description 5
- 238000005096 rolling process Methods 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 239000011230 binding agent Substances 0.000 description 4
- 238000001354 calcination Methods 0.000 description 4
- 239000010419 fine particle Substances 0.000 description 4
- 239000010802 sludge Substances 0.000 description 4
- 238000005303 weighing Methods 0.000 description 4
- 230000009286 beneficial effect Effects 0.000 description 3
- 239000011575 calcium Substances 0.000 description 3
- 229910000019 calcium carbonate Inorganic materials 0.000 description 3
- 229910052918 calcium silicate Inorganic materials 0.000 description 3
- 235000012241 calcium silicate Nutrition 0.000 description 3
- 238000011049 filling Methods 0.000 description 3
- 238000004064 recycling Methods 0.000 description 3
- 238000006722 reduction reaction Methods 0.000 description 3
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 3
- 235000012239 silicon dioxide Nutrition 0.000 description 3
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 2
- 239000003929 acidic solution Substances 0.000 description 2
- 238000005054 agglomeration Methods 0.000 description 2
- 230000002776 aggregation Effects 0.000 description 2
- 229910000272 alkali metal oxide Inorganic materials 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- JHLNERQLKQQLRZ-UHFFFAOYSA-N calcium silicate Chemical compound [Ca+2].[Ca+2].[O-][Si]([O-])([O-])[O-] JHLNERQLKQQLRZ-UHFFFAOYSA-N 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 2
- 229910052593 corundum Inorganic materials 0.000 description 2
- 229910052906 cristobalite Inorganic materials 0.000 description 2
- BCAARMUWIRURQS-UHFFFAOYSA-N dicalcium;oxocalcium;silicate Chemical compound [Ca+2].[Ca+2].[Ca]=O.[O-][Si]([O-])([O-])[O-] BCAARMUWIRURQS-UHFFFAOYSA-N 0.000 description 2
- 230000029087 digestion Effects 0.000 description 2
- 238000001879 gelation Methods 0.000 description 2
- 230000036571 hydration Effects 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 230000036632 reaction speed Effects 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 239000000377 silicon dioxide Substances 0.000 description 2
- 239000002910 solid waste Substances 0.000 description 2
- 229910052682 stishovite Inorganic materials 0.000 description 2
- 235000019976 tricalcium silicate Nutrition 0.000 description 2
- 229910021534 tricalcium silicate Inorganic materials 0.000 description 2
- 229910052905 tridymite Inorganic materials 0.000 description 2
- 229910001845 yogo sapphire Inorganic materials 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- VVTSZOCINPYFDP-UHFFFAOYSA-N [O].[Ar] Chemical compound [O].[Ar] VVTSZOCINPYFDP-UHFFFAOYSA-N 0.000 description 1
- 239000012445 acidic reagent Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000000378 calcium silicate Substances 0.000 description 1
- OYACROKNLOSFPA-UHFFFAOYSA-N calcium;dioxido(oxo)silane Chemical compound [Ca+2].[O-][Si]([O-])=O OYACROKNLOSFPA-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000012770 industrial material Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 229910052909 inorganic silicate Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000007781 pre-processing Methods 0.000 description 1
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- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
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- 239000002912 waste gas Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 239000011787 zinc oxide Substances 0.000 description 1
Abstract
The invention discloses a method for preparing cold-bonded pellets based on alkali-activated steel slag and a product obtained by the method, and belongs to the technical field of pellet preparation. The method of the invention comprises the steps of: step one, steel slag pore-forming pretreatment to obtain porous steel slag; step two, preparing alkali-activated steel slag; grinding and screening the alkali-containing dust to a certain granularity, and carrying out wind power mixing with the porous steel slag to obtain alkali-activated steel slag; step three, adding water into the alkali-activated steel slag and the metallurgical dust mud, uniformly mixing, and pressing into green balls; and fourthly, introducing industrial waste gas, and performing carbonation consolidation treatment on the green pellets to obtain cold-bonded pellets. The method can effectively improve the strength of the cold bonded pellets, and the cold bonded pellets are applied to the rotary hearth furnace process for treating zinc-containing dust, and are dried and roasted, so that the strength of the produced metallized finished pellets is more than or equal to 1700N/Pellet, the yield is more than 75%, and the metallization rate is more than 80%.
Description
Technical Field
The invention belongs to the technical field of pellet preparation, and particularly relates to a method for preparing cold-bonded pellets based on alkali-activated steel slag and an obtained product.
Background
Steel-making slag (SS) is a by-product of the metallurgical industry and mainly includes Basic Oxygen Furnace (BOF) slag, electric Arc Furnace (EAF) slag, argon Oxygen Decarburization (AOD) slag, ladle refining (LF) slag, and the like. Wherein, the average content of CaO in the steel slag is above 30wt%, the content of SiO 2 is above 10wt%, and the average content of MgO is above 5wt%, and the main component of the steel slag is similar to the binder component used by the cold-bonded pellets, and can become one of the substitute materials of the cold-bonded binder.
However, the steel slag undergoes a high temperature and quenching process in the forming process, the mineral is well crystallized, the crystal grains are coarse, the structure is compact, the hydration speed is slow, and the gelation activity is low, so that the carbonation reaction speed of the steel slag is very slow, when the steel slag is used as a binder to prepare the cold-bonded pellets, the curing time of the pellets is prolonged, the mechanical properties of the prepared cold-bonded pellets and the metallized pellets prepared by roasting the cold-bonded pellets are influenced, and the application of the steel slag in the cold-bonded pellets and metallized products thereof is limited.
Therefore, an effective method is needed, the difficult problem of application of the steel slag in the cold bonded pellets and the metallized products thereof is solved, a new way is provided for digestion of the steel slag, and the recycling utilization rate of waste industrial materials is improved.
Disclosure of Invention
1. Problems to be solved
Firstly, aiming at the problem that the steel slag cannot be directly used for preparing the cold bonded pellets and the metallized products thereof in the prior art, the invention provides a method for preparing the cold bonded pellets based on the alkali-activated steel slag, which can effectively solve the problems by preprocessing the steel slag and doping sintering machine head ash into the preprocessed steel slag to prepare the alkali-activated steel slag.
Secondly, the invention also provides the cold bonded pellets prepared by the method and the metallized products thereof, and the prepared cold bonded pellets have green Pellet strength reaching more than 170N/Pellet after being solidified for 3 hours, and meet the requirement of rotary hearth furnace production on the strength of raw materials entering the furnace. Roasting the cold bonded pellets, wherein the strength of the prepared metallized pellets is more than or equal to 1700N/Pellet, and the metallization rate is more than 80%.
2. Technical proposal
In order to solve the problems, the technical scheme adopted by the invention is as follows:
the invention provides a method for preparing cold bonded pellets based on alkali-activated steel slag, which specifically comprises the following steps:
step one, steel slag pore-forming pretreatment;
Step two, preparing alkali-activated steel slag;
grinding and screening the alkali-containing dust to a certain granularity, and carrying out wind power mixing with the porous steel slag to obtain alkali-activated steel slag;
step three, adding water into the alkali-activated steel slag and the metallurgical dust mud, uniformly mixing, and pressing into green balls;
And fourthly, introducing industrial waste gas, and performing carbonation consolidation treatment on the green pellets to obtain cold-bonded pellets.
The preparation method of the invention has the innovation points that:
Firstly, in order to preliminarily solve the problem of low activity of the steel slag, the applicant pre-processes the steel slag, specifically, performs acidic pore-forming treatment on the steel slag to remove free CaO on the surface of the steel slag and form holes, so that the activity of the steel slag is improved, the subsequent carbonation reaction process is improved, and the curing time of the steel slag cooled agglomerated pellet is effectively shortened.
Meanwhile, in the process of adding acid for pore forming, the content of free CaO in steel slag can be reduced, the problems of cracking of pellets and the like caused by volume expansion of free CaO in the subsequent carbonation process can be prevented, and the consolidation strength of the obtained cooled pellets can be effectively ensured, so that the production requirement of a rotary hearth furnace is met.
And secondly, filling the porous steel slag formed after the acidic pore-forming treatment with sintering machine head ash to prepare alkali-activated steel slag, wherein the sintering machine head ash contains K 2O、Na2 O and other alkali oxides, and the alkali oxides react with water in pores on the surface of the steel slag to form an alkali environment. On the one hand, the generated alkaline substances can promote hydration reaction of silicate in the steel slag and accelerate generation of gel substances, and the gel substances can fill pores of raw material particles, so that the strength of the cold-bonded pellets is improved.
The method has the innovation point that the obtained alkali-activated steel slag and metallurgical dust mud are mixed and pressed into balls, the hydration reaction of active substances such as dicalcium silicate, tricalcium silicate and the like in the steel slag is accelerated compared with the steel slag without adding sintering machine head ash, a larger amount of soluble Ca 2+ and silicic acid gel can be formed, industrial waste gas is introduced into the prepared green balls to carry out carbonation treatment on the green balls, the cold-bonded balls are prepared, ca 2+ reacts with CO 2 dissolved in the solution to generate calcium carbonate precipitates, and the calcium carbonate precipitates and the gel are filled in the gaps among raw material particles, so that the strength of the balls is improved.
In a further preferred aspect of the present invention, in the first step, the steel slag is ground in a ball mill, and then immersed in an acidic solution for pickling. Specifically, grinding the steel slag until the mass percentage content of the steel slag with the granularity of-0.149 mm is more than or equal to 95%; the acidic solution adopts a mixed solution of formic acid and acetic acid, wherein the formic acid is as follows: acetic acid molar concentration ratio 1: (0.5-2) mol/L.
Specifically, in the process of pickling the steel slag, the content of free CaO in the steel slag is reduced to 0.1% -0.3%, the content of f-CaO is reduced, so that f-CaO is leached, holes become more, subsequent carbonation is facilitated, but the content of f-CaO cannot be reduced to be too low, the strength of the steel slag is deteriorated and becomes brittle due to the too low content of f-CaO, and therefore, the f-CaO content is controlled to be in a range of 0.1% -0.3% in the invention to be excellent.
The treatment method solves the defects of poor stability and low activity of the steel slag as a binding material, and the formed porous steel slag can effectively increase the specific surface area of the steel slag and the contact point of effective components such as CO 2 and silicate, and strengthen the carbonation efficiency, thereby improving the strength of the cold-bonded pellets and the emission reduction efficiency of CO 2.
In a further preferred aspect of the present invention, in the second step, the mass ratio of the alkali-containing dust to the steel slag is (0.04 to 0.10): 1, uniformly mixing for 10-30 min, wherein the alkali-containing dust adopts sintering machine head ash, and comprises the following main chemical components in percentage by mass: TFe: 20-40%, K 2O：3～12％、Na2 O:0.2 to 8.0% and other unavoidable impurities. More preferably, under the addition amount of the invention, the sum of K 2 O and Na 2 O in the sintering machine head ash is controlled to be between 10 and 20 percent of the total components. And grinding the sintering machine head ash to the particle size of-13 mu m, wherein the mass percentage content of the sintering machine head ash is controlled to be more than or equal to 95 percent, and the sintering machine head ash has larger specific surface area and is easier to enter and adsorb in holes on the surface of porous steel slag under the particle size, so that the sintering machine head ash is more fully contacted with active substances in the steel slag, when the particle size is overlarge, the sintering machine head ash particles cannot fill the holes of the steel slag, when the particle size is overlarge, the specific surface area of the sintering machine head ash is overlarge, self agglomeration is easy to occur, and the filling effect is reduced.
Porous steel slag is treated by using the sintering machine head ash, so that the hydration process of substances such as calcium silicate and the like in the steel slag is accelerated, more gel substances are formed, and the strength of the cold-bonded pellets is improved. The invention optimally designs the addition amount of the sintering machine head ash, and has the advantages of too little addition amount, poor excitation effect and slow hydration reaction; when the addition amount is too high, the alkali-aggregate reaction is accelerated, namely, alkali substances in the head ash of the sintering machine react with silicate in the steel slag too quickly, the volume of the slag expands, the steel slag framework and a newly generated gel structure are damaged, and the strength of the cold-bonded pellets is reduced.
As a further preferred aspect of the present invention, the steel slag has a chemical composition of CaO：40～60％、Fe2O3：10～20％、SiO2：4～12％、MgO：3～10％、MnO：1～5％、P2O5：1～3％、Al2O3：2～8％、TiO2：1～4％ and other unavoidable impurities in mass percent.
As a further preferred aspect of the present invention, in the third step, the mass ratio of the steel slag to the metallurgical dust mud is 1: (10-20), wherein the metallurgical dust and mud is blast furnace dust or OG mixed dust and mud, the granularity is-0.074 mm, and the mass percentage content of the particle size is more than or equal to 80%. The content of effective bonding components and the chemical components of raw materials can be regulated and controlled by controlling the proportion of steel slag and metallurgical dust mud, and a pair of roller ball presses is adopted for pressing during pressing, the rolling is controlled to be 25MPa, and the water content of pressed balls is controlled to be 14%.
As a further preferred aspect of the present invention, the metallurgical dust and sludge is a combination of blast furnace dust and OG mixed dust and sludge, wherein the mass ratio of blast furnace dust to OG mixed dust and sludge is 1: (3-4) the cold bonded pellets produced by the method need to contain a certain amount of carbon for the reduction reaction of iron oxide and zinc oxide, and the mixture ratio of blast furnace ash and OG mixed dust and sludge is suitable, so that the final quality of the pellets is facilitated.
In the fourth step, raw balls are placed in a curing box, industrial waste gas is introduced into the curing box for carbonation and consolidation, the industrial waste gas is sintering flue gas or rotary hearth furnace flue gas, the flow rate of the introduced industrial waste gas is 30000-80000 m 3/h, the temperature is 150-220 ℃, the concentration of CO 2 is 4-8wt%, the content of CO is 0.3-2wt%, the water content is 4-8wt%, and the treatment duration is 3-9h.
According to the invention, the industrial waste gas is introduced, a new way is provided for recycling waste gas, and the carbonation process can be further enhanced and promoted by introducing the industrial flue gas into the alkali-activated steel slag, and common air is adopted for carbonation, wherein the content of CO 2 is only 0.04wt% and the content of CO 2 in the industrial waste gas is 4-8wt%, so that carbonation can be accelerated. Meanwhile, the industrial flue gas has a certain temperature (generally 150-200 ℃), and besides, the H 2 O content in the industrial flue gas is 4-8wt% and the CO content is 0.3-2wt% which are beneficial to the carbonation reaction.
In addition, the steel slag contains metal oxides such as Mn, fe and the like, and the flue gas is introduced into the steel slag to catalyze CO in the flue gas to be converted into CO 2, release heat to improve the wind temperature by 20-30 ℃ and the conversion rate at 180 ℃ to be 60-70%, so that the concentration and the reaction temperature of CO 2 are further improved, and the carbonation reaction process is further accelerated.
Secondly, the invention provides the cold bonded pellets prepared by the preparation method, and the green Pellet strength of the pellets obtained after 3 hours of bonding reaches 170N/Pellet, thereby meeting the requirement of rotary hearth furnace production on the strength of raw materials entering the furnace.
Thirdly, the invention provides a method for preparing metallized pellets by adopting the cold bonded pellets, which comprises the steps of placing the cold bonded pellets in a rotary hearth furnace for drying and roasting at the drying temperature of 150-250 ℃ for 5-10min, and roasting at the roasting temperature of 1250-1350 ℃ for 15-25min, wherein zinc-containing dust in the rotary hearth furnace can be treated through the treatment; on the other hand, the metallized finished pellets used as the converter coolant can be produced.
Fourth, the invention also provides a metallized finished Pellet produced based on the cold bonded Pellet, the strength of the metallized finished Pellet is more than or equal to 1700N/Pellet, the rate of the finished Pellet is more than 75%, and the metallization rate is more than 80%.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) According to the method for preparing the cold-bonded pellets based on the alkali-activated steel slag, acid pore-forming is carried out on the steel slag, the activity of the steel slag is improved, porous steel slag is prepared, and the porous steel slag is further mixed with sintering machine head ash, so that the alkali-activated steel slag is prepared, the activity of the steel slag is remarkably improved, the problems that the existing steel slag is poor in activity and difficult to use for preparing the cold-bonded pellets are effectively solved, meanwhile, the strength of the prepared cold-bonded pellets can be further improved after the sintering machine head ash is added, the strength of the pellets after 3h of bonding is more than 170N/Pellet, and the method has good mechanical properties.
(2) The invention relates to a method for preparing a cold-bonded pellet based on alkali-activated steel slag, which mainly comprises the steps of taking steel slag, sintering machine head ash and metallurgical dust mud as raw materials, and finally introducing industrial waste gas for carbonation treatment, wherein the cold-bonded pellet is prepared by adopting metallurgical solid waste, so that the manufacturing cost of the existing cold-bonded pellet is remarkably reduced (the existing cold-bonded pellet is usually required to be additionally added when preparing the cold-bonded pellet, and the modified steel slag is adopted to replace the binder for preparation in the prior art), the recycling utilization efficiency of the industrial solid waste is improved, and a good way is provided for digestion and treatment of the industrial waste.
(3) According to the method for preparing the cold bonded pellets based on the alkali-activated steel slag, disclosed by the invention, the steel slag is subjected to grinding and acid modification, free CaO in the steel slag can be removed on one hand, a pore channel is formed, the steel slag is made into porous steel slag, the specific surface area of the steel slag and the contact point of effective components such as CO 2 and silicate are increased, the subsequent reinforcement of the carbonation efficiency is facilitated, and the strength of the cold bonded pellets and the CO 2 emission reduction efficiency are improved. In addition, the efficiency and effect of steel slag acidic pore-forming can be further improved through optimizing the used acidic reagent and the addition amount thereof.
(4) According to the method for preparing the cold-bonded pellets based on the alkali-activated steel slag, disclosed by the invention, the added amount of the sintering machine head ash is optimally designed, so that the activity of the steel slag is further activated, the strength of the obtained pellets is ensured, the volume expansion caused by alkali-aggregate reaction is reduced, the excitation effect of the steel slag is improved, and the proper hydration reaction speed is maintained.
(5) The strength of the cold bonded pellets prepared by the method reaches more than 170N/Pellet after the green pellets are bonded for 3 hours, meets the requirement of rotary hearth furnace production on the strength of raw materials entering the furnace, is applied to the rotary hearth furnace process for treating zinc-containing dust, and is subjected to drying and roasting treatment, so that the strength of the produced metallized finished pellets is more than or equal to 1700N/Pellet, the Pellet yield is more than 75%, and the metallization rate is more than 80%.
Drawings
FIG. 1 is a schematic flow chart of a method for preparing cold bonded pellets according to the present invention;
Detailed Description
The steel slag used in the following examples contains ：CaO：49.90％、Fe2O3：24.52％、SiO2：11.67％、MgO：3.94％、MnO：2.13％、P2O5：2.54％、Al2O3：2.90％、TiO2：1.27％, as a concrete component and the balance of unavoidable impurities.
The chemical composition and mass percentage of the sintering machine head ash are TFe:32.5%, K 2O：8.122％、Na2 O:3.420%, and other unavoidable impurities.
The invention is further described below in connection with specific embodiments.
Example 1
As shown in fig. 1, the method for preparing the cold-bonded pellets based on the alkali-activated steel slag in the embodiment comprises the following steps:
(1) Carrying out steel slag pore-forming pretreatment to obtain porous steel slag;
In this embodiment, the mass ratio is 1:0.06:15 weighing a certain amount of steel slag, sintering machine head ash and metallurgical dust mud for standby, firstly placing the steel slag in a ball mill for grinding to fine particle size, and controlling the mass percentage content of the steel slag particle size to be-0.149 mm particle size to be more than or equal to 95%. Then adding a mixed solution of formic acid and acetic acid (the molar concentration ratio of the formic acid to the acetic acid is 1:1.2 mol/L) for pickling, and controlling the content of free CaO to be reduced to 0.2 percent to prepare the porous steel slag.
(2) Preparing alkali-activated steel slag;
grinding the alkali-containing dust to the mass percentage content of the grain grade with the granularity of-13 mu m of more than or equal to 95%, and then carrying out wind power mixing with the porous steel slag for 20min to obtain the alkali-activated steel slag.
(3) Uniformly mixing the alkali-activated steel slag and the metallurgical dust mud, and pressing to prepare green pellets;
Adding water into the alkali-activated steel slag and metallurgical dust mud (namely the mixture of blast furnace ash and OG mixed dust mud according to the mass ratio of 1:3.5), uniformly mixing, pressing into green pellets, wherein the rolling pressure is controlled to be 25MPa, and the water content of the pressed pellets is controlled to be 14%.
(4) Carrying out carbonation consolidation treatment on the green pellets;
And (3) introducing sintering flue gas or rotary hearth furnace flue gas into the green pellets for carbonation consolidation treatment, wherein the flow rate of the introduced industrial waste gas is 60000m 3/h, the temperature is 180 ℃, the concentration of CO 2 is 6%, the water content is 6%, and the treatment time is 6h, so as to obtain the cold-bonded pellets.
Drying and roasting the obtained cold concreted pellets to prepare metallized finished pellets, wherein the specific operation is as follows:
Drying at 200deg.C for 5min, and calcining at 1300deg.C for 20min to obtain pellets.
The obtained cold bonded pellets and the baked metallized finished pellets were subjected to performance detection, and the detection results are shown in table 1.
Comparative example 1
The preparation method of the cold bonded pellets of this comparative example is different from example 1 in that: the porous steel slag and metallurgical dust mud after acidic pore-forming are directly mixed and pressed without the second treatment, and the other process operation and process parameters are the same as those of the embodiment 1.
The obtained cold bonded pellets and the baked metallized finished pellets were subjected to performance detection, and the detection results are shown in table 1.
Comparative example 2
The preparation method of the cold bonded pellets of this comparative example is different from example 1 in that: in the comparative example, the mass ratio of the steel slag to the sintering machine head ash is 1:0.04, and the rest of the process operation and process parameters are the same as in example 1.
The obtained cold bonded pellets and the baked metallized finished pellets were subjected to performance detection, and the detection results are shown in table 1.
Comparative example 3
The preparation method of the cold bonded pellets of this comparative example is different from example 1 in that: in the comparative example, the mass ratio of the steel slag to the sintering machine head ash is 1:0.10, and the rest of the process operation and process parameters are the same as in example 1.
The obtained cold bonded pellets and the baked metallized finished pellets were subjected to performance detection, and the detection results are shown in table 1.
Comparative example 4
The preparation method of the cold bonded pellets of this comparative example is different from example 1 in that: the particle size of the sinter is-2 μm not less than 95%, and the rest of the process operation and process parameters are the same as those of the embodiment 1.
The obtained cold bonded pellets and the baked metallized finished pellets were subjected to performance detection, and the detection results are shown in table 1.
Comparative example 5
The preparation method of the cold bonded pellets of this comparative example is different from example 1 in that: the particle size of the sinter is-100 μm not less than 65%, and the rest of the process operation and process parameters are the same as those of the embodiment 1.
The obtained cold bonded pellets and the baked metallized finished pellets were subjected to performance detection, and the detection results are shown in table 1.
Example 2
The method for preparing the cold-bonded pellets based on the alkali-activated steel slag of the embodiment comprises the following steps:
(1) Carrying out steel slag pore-forming pretreatment to obtain porous steel slag;
In this embodiment, the mass ratio is 1:0.04:10, weighing a certain amount of steel slag, sintering machine head ash and metallurgical dust mud for standby, firstly placing the steel slag in a ball mill for grinding to fine particle size, and controlling the mass percentage content of the steel slag particle size to be-0.149 mm particle size to be more than or equal to 95%. Then adding a mixed solution of formic acid and acetic acid (the molar concentration ratio of the formic acid to the acetic acid is 1:2 mol/L) for pickling, and controlling the content of free CaO to be reduced to 0.25 percent to prepare the porous steel slag.
(2) Preparing alkali-activated steel slag;
Grinding the alkali-containing dust to the mass percentage content of the grain grade with the granularity of-13 mu m of more than or equal to 95%, and then carrying out wind power mixing with the porous steel slag for 10min to obtain the alkali-activated steel slag.
(3) Uniformly mixing the alkali-activated steel slag and the metallurgical dust mud, and pressing to prepare green pellets;
adding water into the alkali-activated steel slag and metallurgical dust mud (namely a mixture of blast furnace ash and OG mixed dust mud according to the mass ratio of 1:4), uniformly mixing, pressing into green pellets, wherein the rolling pressure is controlled to be 20MPa, and the water content of the pressed pellets is controlled to be 14%.
(4) Carrying out carbonation consolidation treatment on the green pellets;
and (3) introducing sintering flue gas or rotary hearth furnace flue gas into the green pellets for carbonation consolidation treatment, wherein the flow rate of the introduced industrial waste gas is 30000m 3/h, the temperature is 220 ℃, the concentration of CO 2 is 8%, the water content is 9%, and the treatment time is 9h, so as to obtain the cold-bonded pellets.
Drying and roasting the obtained cold concreted pellets to prepare metallized finished pellets, wherein the specific operation is as follows:
drying at 150deg.C for 10min, and calcining at 1350 deg.C for 15min to obtain pellets.
The obtained cold bonded pellets and the baked metallized finished pellets were subjected to performance detection, and the detection results are shown in table 1.
Example 3
The method for preparing the cold-bonded pellets based on the alkali-activated steel slag of the embodiment comprises the following steps:
(1) Carrying out steel slag pore-forming pretreatment to obtain porous steel slag;
in this embodiment, the mass ratio is 1:0.1:20, weighing a certain amount of steel slag, sintering machine head ash and metallurgical dust mud for standby, firstly placing the steel slag in a ball mill for grinding to fine particle size, and controlling the mass percentage content of the steel slag particle size to be-0.149 mm particle size to be more than or equal to 95%. Then adding a mixed solution of formic acid and acetic acid (the molar concentration ratio of the formic acid to the acetic acid is 1:1.2 mol/L) for pickling, and controlling the content of free CaO to be reduced to 0.3 percent to prepare the porous steel slag.
(2) Preparing alkali-activated steel slag;
grinding the alkali-containing dust to the mass percentage content of the grain grade with the granularity of-13 mu m of more than or equal to 95%, and then carrying out wind power mixing with the porous steel slag for 20min to obtain the alkali-activated steel slag.
(3) Uniformly mixing the alkali-activated steel slag and the metallurgical dust mud, and pressing to prepare green pellets;
Adding water into the alkali-activated steel slag and metallurgical dust mud (namely the mixture of blast furnace dust and OG mixed dust mud according to the mass ratio of 1:3), uniformly mixing, pressing into green pellets, wherein the rolling pressure is controlled to be 28MPa, and the water content of the pressed pellets is controlled to be 13%.
(4) Carrying out carbonation consolidation treatment on the green pellets;
And (3) introducing sintering flue gas or rotary hearth furnace flue gas into the green pellets for carbonation consolidation treatment, wherein the flow rate of the introduced industrial waste gas is 50000m 3/h, the temperature is 150 ℃, the concentration of CO 2 is 7%, the water content is 6%, and the treatment time is 3h, so as to obtain the cold-bonded pellets.
Drying and roasting the obtained cold concreted pellets to prepare metallized finished pellets, wherein the specific operation is as follows:
drying at 200deg.C for 8min, and calcining at 1300deg.C for 20min to obtain pellets.
The obtained cold bonded pellets and the baked metallized finished pellets were subjected to performance detection, and the detection results are shown in table 1.
Example 4
The method for preparing the cold-bonded pellets based on the alkali-activated steel slag of the embodiment comprises the following steps:
(1) Carrying out steel slag pore-forming pretreatment to obtain porous steel slag;
In this embodiment, the mass ratio is 1:0.06:15 weighing a certain amount of steel slag, sintering machine head ash and metallurgical dust mud for standby, firstly placing the steel slag in a ball mill for grinding to fine particle size, and controlling the mass percentage content of the steel slag particle size to be-0.149 mm particle size to be more than or equal to 95%. Then adding a mixed solution of formic acid and acetic acid (the molar concentration ratio of the formic acid to the acetic acid is 1:0.5 mol/L) for pickling, and controlling the content of free CaO to be reduced to 0.1 percent to prepare the porous steel slag.
(2) Preparing alkali-activated steel slag;
Grinding the alkali-containing dust to the mass percentage content of the grain grade with the granularity of-13 mu m of more than or equal to 95%, and then carrying out wind power mixing with the porous steel slag for 30min to obtain the alkali-activated steel slag.
(3) Uniformly mixing the alkali-activated steel slag and the metallurgical dust mud, and pressing to prepare green pellets;
Adding water into the alkali-activated steel slag and metallurgical dust mud (namely the mixture of blast furnace ash and OG mixed dust mud according to the mass ratio of 1:3.5), uniformly mixing, pressing into green pellets, wherein the rolling pressure is controlled to be 30MPa, and the water content of the pressed pellets is controlled to be 15%.
(4) Carrying out carbonation consolidation treatment on the green pellets;
And (3) introducing sintering flue gas or rotary hearth furnace flue gas into the green pellets for carbonation consolidation treatment, wherein the flow rate of the introduced industrial waste gas is 80000m 3/h, the temperature is 190 ℃, the concentration of CO 2 is 4%, the water content is 4%, and the treatment time is 9h, so as to obtain the cold-bonded pellets.
Drying and roasting the obtained cold concreted pellets to prepare metallized finished pellets, wherein the specific operation is as follows:
Drying at 200deg.C for 5min, and calcining at 1250 deg.C for 25min to obtain pellets.
The obtained cold bonded pellets and the baked metallized finished pellets were subjected to performance detection, and the detection results are shown in table 1.
Table 1 results of performance tests of pellets obtained in examples and comparative examples
As can be seen from the data of table 1, in comparative example 1, after the steel slag is subjected to acidic pore formation, porous steel slag and metallurgical dust mud are directly mixed and pressed without adding sintering machine head ash, and industrial waste gas is introduced to carry out carbonation treatment, so that the strength of the obtained green pellets, namely carbonated pellets, is lower than that of example 1, which shows that adding the sintering machine head ash is beneficial to strengthening the gelation activity of the steel slag and increasing the production amount of gelled substances. This is mainly because the sintering machine head ash contains an alkaline oxide such as K 2O、Na2 O, which reacts with water to form an alkaline substance, and an alkaline environment is formed in micropores on the surface of the steel slag, which is favorable for hydration reaction of silicate active substances such as dicalcium silicate and tricalcium silicate in the steel slag, and the sintering machine head ash is filled in micropores of porous steel slag in example 1, so as to increase contact points between the alkaline substance and the steel slag active substances.
Analysis shows that the carbonation process can be divided into the following steps: (1) CO 2 is adsorbed and dissolved in the water layer on the surface of the particles, H 2CO3;(2)H+ is generated to react with C 2 S to generate soluble Ca 2+ and silicic acid gel (H 4SiO4);(3)Ca2+ reacts with HCO 3- to form CaCO 3 layer on the surface of the particles. After the sintering machine head ash is added, the alkaline environment is formed to facilitate the hydration reaction of the silicate in the step (2), the generation of soluble Ca 2+ and silicic acid gel is promoted, more CaCO 3,CaCO3 is generated in the back carbonation reaction in the step (3) and the gel is filled in the pores of the raw material particles, so that the pellet strength is further increased.
Comparative examples 2 and 3 show that the addition of the sintering machine head ash to the steel slag has an influence on the excitation effect of the activity of the steel slag, and when the addition is large, the alkali-aggregate reaction is accelerated, namely, the alkali substances in the sintering machine head ash react with silicate in the steel slag too quickly, the volume of the alkali substances expands, the steel slag framework and the newly generated gel structure are damaged, and the strength of the cold-bonded pellets is reduced. When the addition amount is small, the excitation effect on the activity of the steel slag is poor, so that the hydration reaction is slow, and the strength of the pellets is not greatly improved.
It is understood from the combination of comparative examples 4 and 5 that the particle size of the sinter head ash added to the steel slag has an influence on the excitation effect of the steel slag activity. When the size of the head ash of the sintering machine is too large, the size of the head ash of the sintering machine is larger than the pore diameter of the micropores of the porous steel slag, the head ash particles cannot fill the pores of the steel slag, and active substances of the steel slag cannot contact with alkaline oxides, so that the active excitation is poor; when the particle size of the head ash is too small, self agglomeration easily occurs due to the fact that the specific surface area of the head ash is too large, so that the head ash is not adsorbed on the steel slag surface, but the head ash contacts with the head ash to form large particles, the filling effect is reduced, and the strength of the pellets cannot be improved.
More specifically, although exemplary embodiments of the present invention have been described herein, the present invention is not limited to these embodiments, but includes any and all embodiments that have been modified, omitted, e.g., combined, adapted, and/or substituted between the various embodiments, as would be recognized by those skilled in the art in light of the foregoing detailed description. The limitations in the claims are to be interpreted broadly based on 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. 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.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In case of conflict, the present specification, definitions, will control. Where a rate, pressure, temperature, time, or other value or parameter is expressed as a range, preferred range, or as a range bounded by a list of upper and lower preferred values, this is to be understood as specifically disclosing all ranges formed from any pair of any upper range limit or preferred value and any lower range limit or preferred value, regardless of whether ranges are separately disclosed. For example, a range of 1-50 should be understood to include any number, combination of numbers, or subranges selected from 1、2、3、4、5、6、7、8、9、10、11、12、13、14、15、16、17、18、19、20、21、22、23、24、25、26、27、28、29、30、31、32、33、34、35、36、37、38、39、40、41、42、43、44、45、46、47、48、49 or 50, and all fractional values between the integers described above, e.g., 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9. Regarding sub-ranges, specifically considered are "nested sub-ranges" that extend from any end point within the range. For example, the nested subranges of exemplary ranges 1-50 can include 1-10, 1-20, 1-30, and 1-40 in one direction, or 50-40, 50-30, 50-20, and 50-10 in another direction.
Claims (10)
1. A method for preparing cold bonded pellets based on alkali-activated steel slag is characterized by comprising the following steps: the method comprises the following steps:
step one, steel slag pore-forming pretreatment to obtain porous steel slag;
Step two, preparing alkali-activated steel slag;
grinding and screening the alkali-containing dust to a certain granularity, and carrying out wind power mixing with the porous steel slag to obtain alkali-activated steel slag;
step three, adding water into the alkali-activated steel slag and the metallurgical dust mud, uniformly mixing, and pressing into green balls;
And fourthly, introducing industrial waste gas, and performing carbonation consolidation treatment on the green pellets to obtain cold-bonded pellets.
2. The method for preparing the cold-bonded pellets based on the alkali-activated steel slag, which is characterized in that: in the second step, the mass ratio of the alkali-containing dust to the steel slag is (0.04-0.10): 1, the mixing time is 10-30 min.
3. The method for preparing the cold-bonded pellets based on the alkali-activated steel slag, which is characterized in that: in the second step, the alkali-containing dust adopts sintering machine head dust, and the alkali-containing dust is ground to the mass percentage content of-13 mu m particle size grade which is more than or equal to 95 percent.
4. The method for preparing the cold-bonded pellets based on the alkali-activated steel slag, which is characterized in that: the chemical composition and mass percentage of the sintering machine head ash are TFe: 20-40%, K 2O：3～12％、Na2 O:0.2 to 8.0% and other unavoidable impurities.
5. The method for preparing the cold-bonded pellets based on the alkali-activated steel slag according to any one of claims 1 to 4, wherein the method comprises the following steps: in the first step, the steel slag is ground to the mass percentage content of the grain grade with the granularity of-0.149 mm to be more than or equal to 95 percent, and then the steel slag is immersed into an acid solution for pickling, and the content of free CaO is controlled to be reduced to 0.1-0.3 percent.
6. The method for preparing the cold-bonded pellets based on the alkali-activated steel slag according to any one of claims 1 to 4, wherein the method comprises the following steps: in the third step, the mass ratio of the steel slag to the metallurgical dust mud is 1: (10-20), wherein the metallurgical dust and mud is blast furnace dust or OG mixed dust and mud, the particle size of the metallurgical dust and mud is-0.074 mm, and the mass percentage content of the particle size is more than or equal to 80%.
7. The method for preparing the cold-bonded pellets based on the alkali-activated steel slag, which is characterized by comprising the following steps of: the metallurgical dust and mud adopts the combination of blast furnace dust and OG mixed dust and mud, and the mass ratio of the blast furnace dust to the OG mixed dust and mud is 1: (3-4).
8. The method for preparing the cold-bonded pellets based on the alkali-activated steel slag according to any one of claims 1 to 4, wherein the method comprises the following steps: and fourthly, placing the green pellets in a curing box, introducing industrial waste gas for carbonation and consolidation, wherein the industrial waste gas is sintering flue gas or rotary hearth furnace flue gas, the flow rate of the introduced industrial waste gas is 30000-80000 m 3/h, the temperature is 150-220 ℃, the concentration of CO 2 is 4-8%, the water content is 4-9%, and the treatment duration is 3-9h.
9. A cold bonded pellet made by the method of any one of claims 1-8, wherein: the green Pellet strength of the obtained Pellet after 3 hours of consolidation reaches more than 170N/Pellet.
10. A metallized finished pellet, characterized in that: the cold bonded pellets produced by the method of any one of claims 1-8 are placed in a rotary hearth furnace for drying and roasting treatment, the strength of the obtained metallized finished pellets is more than or equal to 1700N/Pellet, the Pellet yield is more than 75%, and the metallization rate is more than 80%.
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| CN118389822A true CN118389822A (en) | 2024-07-26 |
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