CN113816571A - Treatment method of cold rolling acid regeneration desilication sludge - Google Patents
Treatment method of cold rolling acid regeneration desilication sludge Download PDFInfo
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- CN113816571A CN113816571A CN202010568356.0A CN202010568356A CN113816571A CN 113816571 A CN113816571 A CN 113816571A CN 202010568356 A CN202010568356 A CN 202010568356A CN 113816571 A CN113816571 A CN 113816571A
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- 239000010802 sludge Substances 0.000 title claims abstract description 69
- 239000002253 acid Substances 0.000 title claims abstract description 56
- 238000000034 method Methods 0.000 title claims abstract description 45
- 230000008929 regeneration Effects 0.000 title claims abstract description 36
- 238000011069 regeneration method Methods 0.000 title claims abstract description 36
- 238000005097 cold rolling Methods 0.000 title claims abstract description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 45
- 239000000460 chlorine Substances 0.000 claims abstract description 34
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910052801 chlorine Inorganic materials 0.000 claims abstract description 30
- 238000006298 dechlorination reaction Methods 0.000 claims abstract description 29
- 238000005406 washing Methods 0.000 claims abstract description 25
- 239000003546 flue gas Substances 0.000 claims abstract description 19
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000012065 filter cake Substances 0.000 claims abstract description 18
- 238000001816 cooling Methods 0.000 claims abstract description 17
- 230000018044 dehydration Effects 0.000 claims abstract description 16
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 16
- 239000000706 filtrate Substances 0.000 claims abstract description 16
- 239000011268 mixed slurry Substances 0.000 claims abstract description 10
- 239000007787 solid Substances 0.000 claims abstract description 10
- 238000010310 metallurgical process Methods 0.000 claims abstract description 8
- 239000003517 fume Substances 0.000 claims abstract description 5
- 238000003825 pressing Methods 0.000 claims description 19
- 239000007788 liquid Substances 0.000 claims description 18
- 239000002699 waste material Substances 0.000 abstract description 19
- 238000004064 recycling Methods 0.000 abstract 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 20
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 15
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 13
- 238000005554 pickling Methods 0.000 description 12
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 11
- 238000002156 mixing Methods 0.000 description 11
- 229910000831 Steel Inorganic materials 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- 238000005245 sintering Methods 0.000 description 8
- 239000010959 steel Substances 0.000 description 8
- 229960002089 ferrous chloride Drugs 0.000 description 7
- 230000000382 dechlorinating effect Effects 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 6
- 229910021577 Iron(II) chloride Inorganic materials 0.000 description 5
- 230000002378 acidificating effect Effects 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- 238000009628 steelmaking Methods 0.000 description 5
- RBTARNINKXHZNM-UHFFFAOYSA-K iron trichloride Chemical compound Cl[Fe](Cl)Cl RBTARNINKXHZNM-UHFFFAOYSA-K 0.000 description 4
- 238000007599 discharging Methods 0.000 description 3
- 229960004887 ferric hydroxide Drugs 0.000 description 3
- IEECXTSVVFWGSE-UHFFFAOYSA-M iron(3+);oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Fe+3] IEECXTSVVFWGSE-UHFFFAOYSA-M 0.000 description 3
- NDLPOXTZKUMGOV-UHFFFAOYSA-N oxo(oxoferriooxy)iron hydrate Chemical compound O.O=[Fe]O[Fe]=O NDLPOXTZKUMGOV-UHFFFAOYSA-N 0.000 description 3
- 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 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- 229910000975 Carbon steel Inorganic materials 0.000 description 2
- 229910021578 Iron(III) chloride Inorganic materials 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000010962 carbon steel Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- -1 hydroxyl ferric oxide Chemical compound 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- VTLYFUHAOXGGBS-UHFFFAOYSA-N Fe3+ Chemical compound [Fe+3] VTLYFUHAOXGGBS-UHFFFAOYSA-N 0.000 description 1
- 238000003723 Smelting Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000002920 hazardous waste Substances 0.000 description 1
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 1
- 238000007131 hydrochloric acid regeneration reaction Methods 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
- 229910000859 α-Fe Inorganic materials 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1418—Recovery of products
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1456—Removing acid components
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
- C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
- C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
- C02F11/122—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using filter presses
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
- B01D2252/10—Inorganic absorbents
- B01D2252/103—Water
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/20—Halogens or halogen compounds
- B01D2257/202—Single element halogens
- B01D2257/2025—Chlorine
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/20—Halogens or halogen compounds
- B01D2257/204—Inorganic halogen compounds
- B01D2257/2045—Hydrochloric acid
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2258/00—Sources of waste gases
- B01D2258/02—Other waste gases
- B01D2258/0283—Flue gases
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/12—Halogens or halogen-containing compounds
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Abstract
The invention discloses a method for treating cold rolling acid regeneration desilication sludge, which comprises the following steps: 1) washing the desiliconized sludge with water according to the water-solid ratio of 5-12: 1; 2) carrying out high-pressure dehydration on the desiliconized sludge mixed slurry generated by water washing to form a filter cake with low water content, and reducing the water content of the filter cake after dehydration to be below 30%; 3) carrying out low-temperature roasting dechlorination on the filter cake, using the filtrate for cooling roasting flue gas or returning the filtrate to an acid regeneration system, wherein the roasting temperature is 300-450 ℃, the roasting time is 30-60min, and the roasting is carried out in the air atmosphere; 4) the roasted residue is used in metallurgical process, the roasted fume is cooled, deacidified, residual chlorine is removed and purified, and then discharged, the produced dilute acid solution is reused, and the chlorine content of the residue is less than 0.3%. The invention realizes the full-scale in-plant recycling of the desiliconized sludge through the technological processes of water washing, high-pressure dehydration and low-temperature roasting, and has simple technological process and no secondary waste discharge.
Description
Technical Field
The invention relates to a method for treating waste, in particular to a method for treating cold rolling acid regeneration desilication sludge.
Background
A large amount of pickling waste liquid is generated after the cold-rolled strip steel is pickled, the main components of the pickling waste liquid are ferrous chloride and a small amount of residual hydrochloric acid, the hydrochloric acid regeneration is usually carried out by adopting a spray roasting method, the pickling waste liquid is returned to a pickling section for continuous application, and simultaneously, iron oxide powder is recovered, wherein the iron oxide powder is the main raw material of a ferrite magnetic material. In order to produce high-quality iron oxide powder and prevent elements such as Si, Al, Mn and the like in steel from entering the iron oxide powder, particularly Si can seriously affect the quality of the iron oxide powder, and the pickling waste liquid needs to be subjected to desilication treatment before entering a regeneration process.
The desilication process in the prior art comprises the following steps: after the pickling waste liquid is reacted in an iron dissolving tank, ammonia water is added to regulate the pH value, and then compressed air is introduced to generate ferric iron to dissolve SiO in the solution2Coating, adding flocculant, and adding Fe (OH)3Together with SiO2Together settling to remove SiO in the pickling solution2And desiliconized sludge produced by dewatering the precipitated concentrated solution by filter pressing and the like. The desiliconized sludge contains 50-65 percent of dry-basis total iron and 10-20 percent of chlorine, is a strong-acid corrosive substance and contains a certain amount of chlorine, so that the desiliconized sludge is limited to be recycled in the internal smelting process of steel, and particularly contains rich FeCl2It is not only the source of chlorine generated by dioxin, but also the catalyst for generating dioxin.
Desiliconized sludge resource utilization the prior art mainly produces pigments, nano materials, bricks and the like by external resource utilization, and a small amount of internal waste is sintered and utilized or is used as hazardous waste to entrust a professional company for disposal; the prior art has long treatment process, complex process, certain potential safety hazard in the process due to the need of using waste acid, ammonia water and other raw materials, and is easy to generate secondary waste or pollutants. Meanwhile, the desiliconized sludge has high chlorine content and strong corrosivity, so that the site selection of the high-added-value utilization and processing of the sludge is difficult.
Disclosure of Invention
The invention aims to provide a treatment method of cold rolling acid regeneration desiliconized sludge, which can realize the full-scale in-plant recovery of the desiliconized sludge through the process flows of water washing, high-pressure dehydration and low-temperature roasting, has simple process flow and does not discharge secondary wastes in the whole process.
The invention is realized by the following steps:
a treatment method of cold rolling acid regeneration desilication sludge comprises the following steps:
step 1: washing the desiliconized sludge;
step 2: carrying out high-pressure dehydration on the desiliconized sludge mixed slurry generated by water washing to form a filter cake with lower water content;
and step 3: roasting the filter cake at low temperature for dechlorination, and utilizing the filtrate in a system;
and 4, step 4: the roasted residue is used in metallurgical process, the roasted fume is cooled, deacidified, residual chlorine is eliminated and purified and exhausted, and the dilute acid liquid produced in the fume purifying process is reused.
In the step 1, when the desiliconized sludge is washed by water, the water-solid ratio is 5-12:1, and the water and the desiliconized sludge are mixed and oscillated for 30-60 min.
In the step 2, the water content of the filter cake with low water content after dehydration is reduced to below 30 percent.
In the step 2, the dehydration is carried out through a high-pressure filter press, the filter-pressing pressure of the high-pressure filter press is more than or equal to 10Mpa, and the filter-pressing dehydration time of the high-pressure filter press is 5-10 min.
In the step 3, the roasting temperature is 300-450 ℃, the roasting time is 30-60min, and the roasting dechlorination operation is carried out in the air atmosphere.
In the step 3, the filtrate is used for a filter cake low-temperature roasting flue gas cooling process or returned to an acid regeneration system.
In the step 4, the chlorine content of the residue is less than 0.3%.
Compared with the prior art, the invention has the following beneficial effects:
1. the method has good dechlorination effect, can economically and efficiently reduce the chlorine content in the residue after the dechlorination of the desiliconized sludge to be less than 0.3 percent through water washing dechlorination and low-temperature roasting deep dechlorination, can return to sintering or a converter for utilization, and solves the problems of high chlorine content in the residue after the dechlorination, complex dechlorination process flow and high cost in the prior art.
2. The invention can fully recover the components in the desiliconized sludge, the main components of the desiliconized sludge are ferrous chloride, ferric hydroxide and hydroxyl ferric oxide, the iron-containing component can be converted into ferric oxide through low-temperature roasting, the main component of the dechlorination product solid residue is ferric oxide which can be used by in-plant sintering and converter, and chlorine is converted into HCl and Cl2The absorption liquid is cooled and absorbed to become dilute acid liquid which can return to an acid regeneration system, thereby realizing the nearby internal utilization of the recovered components.
3. The invention adopts washing dechlorination and low-temperature roasting dechlorination, so that dechlorination products can be completely recycled, secondary waste is not discharged, the problem of secondary pollution is solved, and the method is energy-saving, environment-friendly, simple in process, short in flow and low in cost.
The method can realize the full-scale in-plant recovery of the desiliconization sludge generated by desiliconization treatment before the regeneration of the carbon steel cold rolling hydrochloric acid pickling waste liquid acid through the technological processes of water washing and low-temperature roasting, is favorable for full utilization of the desiliconization sludge dechlorination by-products in the metallurgical process, and has the advantages of good dechlorination effect, simple technological process and low cost.
Drawings
FIG. 1 is a process flow diagram of the treatment method of cold rolling acid regeneration desiliconized sludge of the present invention.
Detailed Description
The invention is further described with reference to the following figures and specific examples.
Referring to the attached figure 1, the treatment method of the cold rolling acid regeneration desilication sludge comprises the following steps:
step 1: and (4) washing the desiliconized sludge. Preferably, when the desiliconized sludge is washed by water, the water-solid ratio is 5-12:1, and the water and the desiliconized sludge are mixed and oscillated for 30-60 min.
The water washing can be ensured to have a better dechlorination effect only when a certain water amount is reached, theoretically, the dechlorination effect is better when the water amount is more, but the concentration of the washing acid liquid is lower after the water amount is too much, so that the utilization of a acid returning regeneration system of the washing acid liquid is not facilitated, the solid content in the washing liquid is lower due to the excessive water amount, the subsequent filter pressing effect is not facilitated, and therefore the water-solid ratio is controlled to be 5-12:1 to be optimal. The mixing oscillation can further ensure the dechlorination effect after reaching a certain time, but the overlong time can cause the increase of energy consumption and cost, so the mixing oscillation time is controlled to be between 30 and 60 minutes to be optimal.
Step 2: and (3) carrying out high-pressure dehydration on the desiliconized sludge mixed slurry generated by water washing to form a filter cake with lower water content.
The dehydration operation of the desiliconized sludge mixed slurry can be carried out by adopting a high-pressure filter pressing mode, so that the water content of the dehydrated filter cake is reduced to below 30 percent. Preferably, the filter pressing pressure of the high-pressure filter press is more than or equal to 10MPa, and the upper limit of the filter pressing pressure is determined by the rated pressure of the high-pressure filter press; the filter-pressing dehydration time of the high-pressure filter press is 5-10 min. The mixed slurry washed by the high-pressure filter-pressing desiliconized sludge can ensure the removal effect of the hydrochloric acid solution in the desiliconized sludge, and can control the water content of the sludge to be below 30 percent, so that more hydrochloric acid solution can be removed, and the pressure of subsequent low-temperature roasting dechlorination is reduced.
And step 3: and (3) feeding the filter cake into a rotary kiln for low-temperature roasting dechlorination, and utilizing the filtrate in a filtrate system, namely, cooling the filtrate used for the low-temperature roasting flue gas of the desiliconized sludge filter cake or returning the filtrate to an acid regeneration system. Preferably, the roasting temperature is 300-450 ℃, the roasting time is 30-60min, and the roasting dechlorination operation is carried out in the air atmosphere.
Because the main phases of the desiliconized sludge are ferrous chloride and hydroxyl oxidationThe iron and the ferric hydroxide, the ferrous chloride dechlorination, the crystal water removal, the hydroxyl ferric oxide and the ferric hydroxide for removing the combined water all need certain reaction temperature, the temperature is too low, the dechlorination effect is poor, the temperature is too high, and the energy consumption is high, so the roasting temperature is controlled to be 300-450 ℃. At the same time, dechlorination of ferrous chloride and production of HCl require oxygen and H2The process can be carried out in the presence of O, and HCl is generated to recover hydrochloric acid and return the hydrochloric acid to an acid regeneration system for reuse, so that roasting dechlorination operation needs to be carried out in an air atmosphere.
The main reaction principle of low-temperature roasting dechlorination is as follows:
FeCl2(s)+1/4O2(g)=2/3FeCl3(s)+1/6Fe2O3(s) (1)
FeCl2(s)+1/4O2(g)+H2O=2HCl(g)+1/2Fe2O3(s) (2)
FeCl3+3/4O2(g)=1/2Fe2O3+3/2Cl2(g) (3)
FeCl3+3/2H2O(g)=1/2Fe2O3+3HCl(g) (4)
and 4, step 4: the roasted residue can be directly returned to the metallurgical processes of sintering or steelmaking and the like in an iron and steel plant for utilization, the roasted flue gas is purified and then discharged, and the dilute acid liquid generated in the flue gas purification process is returned to the acid desilication pretreatment process or the acid regeneration process for reuse.
The flue gas purification treatment comprises the following steps: cooling, deacidifying and removing residual chlorine, namely cooling the flue gas and cooling the flue gas; the cooled flue gas is washed by water to absorb and remove HCl, and can be safely discharged after reaching the standard after being removed by residual chlorine, and FeCl can be used for removing the residual chlorine2The dilute acid solution generated by solution absorption, cooling, deacidification and residual chlorine removal can be returned to an acid regeneration system for utilization.
The chlorine content of the residue is less than 0.3 percent, and the TFe content is generally 66-69 percent, so that the residue can be used for sintering or steelmaking in iron and steel enterprises.
The invention is produced by the desiliconization treatment before the acid regeneration of the carbon steel cold rolling hydrochloric acid pickling waste liquidThe desiliconized sludge is washed by water, and iron dichloride (FeCl) in the desiliconized sludge is utilized2∙4H2O) is washed with water for dechlorination, the mixed slurry after washing is pressed and filtered into a filter cake by high pressure, the filter cake is dechlorinated by a low-temperature roasting method, and iron dichloride and iron trichloride in the filter cake are dechlorinated to generate gaseous HCl and Cl under the conditions of certain temperature and existence of oxygen and moisture2The main component of the dechlorinated residue is ferric oxide which can be returned to the sintering or converter in factory for utilization, and the acidic filtrate generated by high-pressure dehydration after washing the desiliconized sludge can be used for cooling the low-temperature roasting flue gas or directly returned to an acid regeneration system for utilization. Cooling, deacidifying and removing residual chlorine from low-temperature roasting flue gas to obtain HCl and Cl in the flue gas2Can be absorbed in the dilute acid liquid and returned to the acid regeneration system for reuse.
Example 1:
the pickling waste acid of a certain steel mill is subjected to desiliconization treatment to generate desiliconized sludge, the water content of the desiliconized sludge is 45.5%, the TFe content is 53.7%, and the chlorine content on a dry basis is 24.18%. Firstly, pressing water: the solid ratio is 10: 1, mixing and washing desiliconized sludge, fully mixing and oscillating for 45min, carrying out filter pressing on the desiliconized sludge mixed slurry after mixing and oscillating for 10min by using a vertical high-pressure filter press, wherein the pressure is 12MPa, the water content of a desiliconized sludge cake is reduced to 25.6%, the chlorine content of a dry basis is 4.91%, then sending the desiliconized sludge cake into a rotary kiln for roasting and dechlorinating, the roasting temperature is 420 ℃, the roasting time is 50min, discharging residues after dechlorinating, the chlorine content of the dry basis of the residues is 0.21%, the content of TFe is 67.3%, cooling and returning the residues to a metallurgical process (sintering or steelmaking) for utilization; and returning the acidic filtrate generated by high-pressure filter pressing to an acid regeneration desilication system, and merging the acidic filtrate with the waste acid after desilication to perform acid regeneration. The temperature of the flue gas discharged from the rotary kiln is about 380 ℃, the flue gas is discharged after cooling, washing and deacidifying and residual chlorine removing, and the recovered diluted acid liquid is returned to an acid regeneration system for utilization.
Example 2:
the pickling waste acid of a certain steel mill is subjected to desiliconization treatment to generate desiliconized sludge, the water content of the desiliconized sludge is 47.5%, the TFe content is 53.7%, and the chlorine content on a dry basis is 12.38%. Firstly, pressing water: solid ratio 6: 1, mixing and washing desiliconized sludge, fully mixing and oscillating for 30min, carrying out filter pressing on the desiliconized sludge mixed slurry after mixing and oscillating for 6min by using a vertical high-pressure filter press, wherein the pressure is 12MPa, the water content of a desiliconized sludge cake is reduced to 27.6%, the chlorine content of a dry basis is 2.15%, then sending the desiliconized sludge cake into a rotary kiln for roasting and dechlorinating, the roasting temperature is 320 ℃, the roasting time is 45min, discharging residues after dechlorinating, the chlorine content of the dry basis of the residues is 0.16%, the content of TFe is 68.4%, cooling and returning the residues to a metallurgical process (sintering or steelmaking) for utilization; the filtrate is used for cooling the low-temperature roasting smoke. The temperature of the flue gas discharged from the rotary kiln is about 280 ℃, the flue gas is discharged after cooling, washing and deacidifying and residual chlorine removing, and the recovered diluted acid liquid is returned to an acid regeneration system for utilization.
Example 3:
the acid pickling waste acid of a certain steel mill is subjected to desiliconization treatment to generate desiliconized sludge cakes, the water content of the desiliconized sludge is 43.5%, the TFe content is 50.6%, and the chlorine content of a dry basis is 16.32%. Firstly, pressing water: the solid ratio is 8: 1, mixing and washing desiliconized sludge, fully mixing and oscillating for 40min, carrying out filter pressing on the desiliconized sludge mixed slurry after mixing and oscillating for 8min by using a vertical high-pressure filter press, wherein the pressure is 10MPa, the water content of a desiliconized sludge cake is reduced to 26.8%, the chlorine content of a dry basis is 3.35%, then sending the desiliconized sludge cake into a rotary kiln for roasting and dechlorinating, the roasting temperature is 400 ℃, the roasting time is 45min, discharging residues after dechlorinating, the chlorine content of the dry basis of the residues is 0.08%, the content of TFe is 67.9%, cooling and returning the residues to a metallurgical process (sintering or steelmaking) for utilization; and returning the acidic filtrate generated by high-pressure filter pressing to an acid regeneration desilication system, and merging the acidic filtrate with the waste acid after desilication to perform acid regeneration. The temperature of the flue gas discharged from the rotary kiln is about 280 ℃, the flue gas is discharged after cooling, washing and deacidifying and residual chlorine removing, and the recovered diluted acid liquid is returned to an acid regeneration system for utilization.
The present invention is not limited to the above embodiments, and any modifications, equivalent replacements, improvements, etc. within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (7)
1. A treatment method of cold rolling acid regeneration desilication sludge is characterized by comprising the following steps: the method comprises the following steps:
step 1: washing the desiliconized sludge;
step 2: carrying out high-pressure dehydration on the desiliconized sludge mixed slurry generated by water washing to form a filter cake with low water content;
and step 3: roasting the filter cake at low temperature for dechlorination, and utilizing the filtrate in a system;
and 4, step 4: the roasted residue is used in metallurgical process, the roasted fume is cooled, deacidified, residual chlorine is eliminated and purified and exhausted, and the dilute acid liquid produced in the fume purifying process is reused.
2. The method for treating cold rolling acid regeneration desiliconized sludge according to claim 1, characterized in that: in the step 1, when the desiliconized sludge is washed by water, the water-solid ratio is 5-12:1, and the water and the desiliconized sludge are mixed and oscillated for 30-60 min.
3. The method for treating cold rolling acid regeneration desiliconized sludge according to claim 1, characterized in that: in the step 2, the water content of the filter cake with low water content after dehydration is reduced to below 30 percent.
4. The method for treating cold rolling acid regeneration desiliconized sludge according to claim 1, characterized in that: in the step 2, the dehydration is carried out through a high-pressure filter press, the filter-pressing pressure of the high-pressure filter press is more than or equal to 10Mpa, and the filter-pressing dehydration time of the high-pressure filter press is 5-10 min.
5. The method for treating cold rolling acid regeneration desiliconized sludge according to claim 1, characterized in that: in the step 3, the roasting temperature is 300-450 ℃, the roasting time is 30-60min, and the roasting dechlorination operation is carried out in the air atmosphere.
6. The method for treating cold rolling acid regeneration desiliconized sludge according to claim 1, characterized in that: in the step 3, the filtrate is used for a filter cake low-temperature roasting flue gas cooling process or returned to an acid regeneration system.
7. The method for treating cold rolling acid regeneration desiliconized sludge according to claim 1, characterized in that: in the step 4, the chlorine content of the residue is less than 0.3%.
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