CN117776447A - Treatment method of lead-zinc smelting waste acid - Google Patents
Treatment method of lead-zinc smelting waste acid Download PDFInfo
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- 239000002253 acid Substances 0.000 title claims abstract description 56
- 238000000034 method Methods 0.000 title claims abstract description 39
- 239000002699 waste material Substances 0.000 title claims abstract description 31
- 238000003723 Smelting Methods 0.000 title claims abstract description 27
- JQJCSZOEVBFDKO-UHFFFAOYSA-N lead zinc Chemical compound [Zn].[Pb] JQJCSZOEVBFDKO-UHFFFAOYSA-N 0.000 title claims abstract description 26
- 238000004073 vulcanization Methods 0.000 claims abstract description 49
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 46
- 239000011701 zinc Substances 0.000 claims abstract description 28
- 229910052793 cadmium Inorganic materials 0.000 claims abstract description 24
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910052785 arsenic Inorganic materials 0.000 claims abstract description 18
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 claims abstract description 18
- 239000010440 gypsum Substances 0.000 claims abstract description 16
- 229910052602 gypsum Inorganic materials 0.000 claims abstract description 16
- 238000006477 desulfuration reaction Methods 0.000 claims abstract description 3
- 230000023556 desulfurization Effects 0.000 claims abstract description 3
- 239000000706 filtrate Substances 0.000 claims description 28
- 239000007788 liquid Substances 0.000 claims description 21
- HYHCSLBZRBJJCH-UHFFFAOYSA-M sodium hydrosulfide Chemical compound [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 claims description 15
- 229910052716 thallium Inorganic materials 0.000 claims description 14
- BKVIYDNLLOSFOA-UHFFFAOYSA-N thallium Chemical compound [Tl] BKVIYDNLLOSFOA-UHFFFAOYSA-N 0.000 claims description 14
- 238000006243 chemical reaction Methods 0.000 claims description 13
- 235000008733 Citrus aurantifolia Nutrition 0.000 claims description 12
- 235000011941 Tilia x europaea Nutrition 0.000 claims description 12
- 239000004571 lime Substances 0.000 claims description 12
- 238000000926 separation method Methods 0.000 claims description 11
- 239000008267 milk Substances 0.000 claims description 7
- 210000004080 milk Anatomy 0.000 claims description 7
- 235000013336 milk Nutrition 0.000 claims description 7
- 229910052979 sodium sulfide Inorganic materials 0.000 claims description 7
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 claims description 7
- 238000003756 stirring Methods 0.000 claims description 7
- 239000008394 flocculating agent Substances 0.000 claims description 5
- 230000035484 reaction time Effects 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims description 4
- 239000000463 material Substances 0.000 claims description 3
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 claims description 2
- 239000006071 cream Substances 0.000 claims description 2
- 229910000037 hydrogen sulfide Inorganic materials 0.000 claims description 2
- 230000003472 neutralizing effect Effects 0.000 claims description 2
- 239000010802 sludge Substances 0.000 claims description 2
- 238000006386 neutralization reaction Methods 0.000 abstract description 15
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 abstract description 14
- 229910052725 zinc Inorganic materials 0.000 abstract description 14
- 230000002378 acidificating effect Effects 0.000 abstract description 6
- 238000010306 acid treatment Methods 0.000 abstract description 5
- 238000004064 recycling Methods 0.000 abstract description 2
- ZIXVIWRPMFITIT-UHFFFAOYSA-N cadmium lead Chemical compound [Cd].[Pb] ZIXVIWRPMFITIT-UHFFFAOYSA-N 0.000 abstract 1
- YIAVADUIRPWBCA-UHFFFAOYSA-N thallanylidynearsane Chemical compound [Tl]#[As] YIAVADUIRPWBCA-UHFFFAOYSA-N 0.000 abstract 1
- 239000006228 supernatant Substances 0.000 description 36
- 239000011133 lead Substances 0.000 description 23
- 239000002893 slag Substances 0.000 description 21
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 20
- 239000000126 substance Substances 0.000 description 17
- 229910001385 heavy metal Inorganic materials 0.000 description 16
- 238000004519 manufacturing process Methods 0.000 description 14
- 239000012535 impurity Substances 0.000 description 11
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 230000008719 thickening Effects 0.000 description 9
- 238000003825 pressing Methods 0.000 description 7
- 239000012530 fluid Substances 0.000 description 6
- 238000002386 leaching Methods 0.000 description 6
- WUPHOULIZUERAE-UHFFFAOYSA-N 3-(oxolan-2-yl)propanoic acid Chemical compound OC(=O)CCC1CCCO1 WUPHOULIZUERAE-UHFFFAOYSA-N 0.000 description 5
- 239000005083 Zinc sulfide Substances 0.000 description 5
- 229910052980 cadmium sulfide Inorganic materials 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 239000002910 solid waste Substances 0.000 description 5
- 230000001988 toxicity Effects 0.000 description 5
- 231100000419 toxicity Toxicity 0.000 description 5
- 229910052984 zinc sulfide Inorganic materials 0.000 description 5
- DRDVZXDWVBGGMH-UHFFFAOYSA-N zinc;sulfide Chemical compound [S-2].[Zn+2] DRDVZXDWVBGGMH-UHFFFAOYSA-N 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 239000010949 copper Substances 0.000 description 4
- 230000001186 cumulative effect Effects 0.000 description 4
- 238000002474 experimental method Methods 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 238000005987 sulfurization reaction Methods 0.000 description 4
- 239000012295 chemical reaction liquid Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 239000013049 sediment Substances 0.000 description 2
- 239000010865 sewage Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- BUGBHKTXTAQXES-UHFFFAOYSA-N Selenium Chemical compound [Se] BUGBHKTXTAQXES-UHFFFAOYSA-N 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 238000005352 clarification Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
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- 239000000428 dust Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 239000002920 hazardous waste Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 150000002505 iron Chemical class 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 229910052976 metal sulfide Inorganic materials 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- IHYNKGRWCDKNEG-UHFFFAOYSA-N n-(4-bromophenyl)-2,6-dihydroxybenzamide Chemical compound OC1=CC=CC(O)=C1C(=O)NC1=CC=C(Br)C=C1 IHYNKGRWCDKNEG-UHFFFAOYSA-N 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 229910052711 selenium Inorganic materials 0.000 description 1
- 239000011669 selenium Substances 0.000 description 1
- -1 sulfide ions Chemical class 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000003403 water pollutant Substances 0.000 description 1
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- Removal Of Specific Substances (AREA)
- Processing Of Solid Wastes (AREA)
Abstract
The invention relates to a method for treating lead-zinc smelting waste acid, which belongs to the technical field of lead-zinc smelting waste acid treatment and comprises four main steps of primary vulcanization, secondary vulcanization, neutralization to pH value of 3-5 and tertiary desulfurization, wherein in the primary vulcanization, secondary vulcanization and tertiary vulcanization, the addition of vulcanizing agents is respectively controlled by ORP difference values to realize staged removal of arsenic thallium, cadmium lead and zinc, and realize recycling of cadmium and zinc, and meanwhile, as more than 99% of arsenic and more than 99% of cadmium are removed under acidic conditions and before neutralization, gypsum generated by neutralization is prevented from becoming dangerous waste.
Description
Technical Field
The invention belongs to the technical field of lead-zinc smelting waste acid treatment, and particularly relates to a lead-zinc smelting waste acid treatment method.
Background
In the production of acid by smelting flue gas, the waste acid with the sulfuric acid content of about 2-8% can be produced. The contaminated acid contains sulfuric acid and a large amount of mineral dust, and also contains various harmful substances such as arsenic, copper, lead, zinc, cadmium, mercury, selenium, bismuth, fluorine, chlorine and the like, and has the characteristics of high pollutant concentration and complex components, and the contained harmful substances have different properties, so that the expected treatment effect is often difficult to achieve by adopting a single treatment method.
The treatment method of lead-zinc smelting waste acid mainly comprises a lime method (a neutralization precipitation method), an iron salt method and a vulcanization method, or a combination of the above methods is adopted. Compared with a lime method, the sulfuration method has certain advantages that sulfide ions can form indissolvable sediment with arsenic and heavy metal elements, the added materials are few, the slag yield is also greatly reduced, but the single sulfuration method can not lead the polluted acid heavy metal to reach the standard, the sulfuration method needs to be matched with other methods (such as a lime ferric salt method) for treatment, but the sulfuration method can lead the heavy metal to be co-precipitated, and the recycling of the heavy metal elements is inconvenient. The prior art shows that: the addition of the vulcanizing agent can effectively remove impurities in the polluted acid, and the precipitation sequence is Hg according to the solubility product of different metal sulfides 2+ >Cu + >Cu 2+ >Pb 2+ >Cd 2+ >Sn 2+ >Zn 2+ >As 3+ >Tl + . The larger the solubility product of sulfide, the easier it is to dissolve, and the smaller the solubility product, the easier it is to precipitate. For sulphide precipitation, the equilibrium concentration of metal ions in the solution decreases with increasing pH, and decreases with increasing sulphur concentration. The heavy metal removing effect is not only similar to S brought into solution by vulcanizing agent 2- The pH also has an effect on the heavy metal removal, depending on the concentration. Within a certain range, the greater the pH in the solution, the higher the heavy metal removal rate. The prior art shows that the efficiency of removing heavy metals such as arsenic, copper, mercury and the like by vulcanization under an acidic condition is higher, but the removal efficiency of cadmium, thallium, zinc and the like is poor, and the cadmium, thallium and zinc are important monitoring indexes for water pollutant discharge, so that in order to realize the removal of the heavy metals, the conventional combined process of vulcanization, neutralization and vulcanization (such as patent CN107399855A and CN 114772799A) is generally adopted for removing the heavy metals in the polluted acid, and the standard discharge of the polluted acid is difficult to realize due to the fluctuation of the heavy metal content in the polluted acid, and the problems that cadmium and zinc cannot be separated, the medicament cost is increased due to excessive vulcanizing agent and the like exist in the method; in addition, the method for treating the waste acid, cadmium, thallium and other metals cannot be precipitated under the acidic condition, and the metals are entrained into gypsum during neutralization, so that the heavy metal content of the obtained gypsum exceeds the standard, and the gypsum becomes dangerous waste.
Disclosure of Invention
In order to overcome the problems in the background technology, the invention provides a treatment method of lead-zinc smelting waste acid, wherein the addition amount of a vulcanizing agent can be controlled by an OPR difference value, and more than 99% of arsenic, thallium and cadmium precipitates are removed under an acidic condition before neutralization, so that gypsum generated by neutralization is prevented from becoming dangerous waste.
In order to achieve the above purpose, the invention is realized by the following technical scheme:
the treatment method of lead-zinc smelting waste acid comprises the following steps:
(1) First-stage vulcanizing, namely adding the contaminated acid and a vulcanizing agent into a reactor for vulcanization, wherein the adding amount of the vulcanizing agent is As in the contaminated acid 3- And Tl - 1 to 1.2 times of the total molar concentration, wherein the ORP difference value at the inlet and outlet of the reactor is 10 to 100, so that arsenic and thallium are precipitated; and (3) performing solid-liquid separation after vulcanization to obtain a first filtrate and first bottom mud.
(2) Secondary desulfurization, adding the first filtrate and a vulcanizing agent into a reactor, wherein the adding amount of the vulcanizing agent is Pb in the first filtrate 2- 、Cd 2- 、As 3- And Tl - The total molar concentration is 1-1.2 times, the ORP difference of the inlet and outlet of the reactor is 10-100, cadmium is vulcanized and precipitated, and solid-liquid separation is carried out after vulcanization, so as to obtain second filtrate and second bottom mud.
(3) And (3) neutralizing, namely adding lime cream into the second filtrate, controlling the pH value of the reaction end point to be 3-5, and carrying out solid-liquid separation to obtain a third filtrate and gypsum bottom mud.
Furthermore, the treatment method of lead-zinc smelting waste acid also comprises the step (4) of tertiary vulcanization,
specifically, the third filtrate and the vulcanizing agent are added into a reactor, wherein the adding amount of the vulcanizing agent is Zn in the third filtrate 2- 1 to 1.2 times of the molar concentration, the ORP difference value at the inlet and outlet of the reactor is 50 to 200, the pH value of the reaction material is controlled to be 6 to 8, and the solid and the liquid are separated after the reaction is finished, so as to obtain fourth filtrate and fourth bottom sludge.
Further, in the step (3), the reaction time of the second filtrate and lime milk is 0.5-2h, and the stirring speed is 60-100rpm.
Further, the vulcanizing agent is one or more of hydrogen sulfide, sodium sulfide and sodium hydrosulfide.
Further, the pressure of the reactor is 0.1-0.3MPa, the stirring speed is 500-800rpm, and the reaction time is 3-60s.
In the step (4), a flocculating agent is added after three-stage vulcanization, and then liquid-solid separation is carried out.
The invention has the beneficial effects that:
(1) According to the invention, the adding amount of the vulcanizing agent can be determined according to the ORP difference value in the production process, so that the vulcanizing agent is accurately added, the accurate removal of different substances in the polluted acid is realized, the sectional and step precipitation of different substances in the polluted acid is finally realized, the purity of the separated substances is improved, and the recovery of impurities, particularly the recovery of zinc and cadmium is realized.
(2) The invention can lead arsenic, thallium and cadmium to be precipitated and separated out under the acidic condition before the neutralization to the pH value of 3-5, and the precipitation rate is more than 99 percent, so that the heavy metal content in the gypsum product obtained by the subsequent neutralization is greatly reduced, and the toxicity leaching experiment shows that the obtained gypsum is general solid waste and has remarkable environmental protection benefit.
(3) The method can deeply remove arsenic, thallium, lead, zinc and cadmium in the contaminated acid, effectively solves the problem that the arsenic, thallium, lead, zinc and cadmium in the lead-zinc smelting contaminated acid cannot reach the standard stably, and the treated contaminated acid reaches the emission requirement of GB25466-2010 emission Standard of lead-zinc industrial pollutants.
(4) Compared with the prior art, the method has the advantages that the pH value of the thallium and cadmium precipitate is obviously reduced, the thallium and cadmium impurities are removed under the acidic condition, and the recovered cadmium can be recycled.
(5) The invention only uses the slag generated by primary vulcanization as dangerous waste, and the rest can be recycled, thereby greatly reducing the dangerous waste output of lead-zinc smelting waste acid.
Drawings
Fig. 1 is a process flow diagram of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantageous effects of the present invention more apparent, the technical solutions of the present invention will be described in detail below, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, other embodiments that may be obtained by those skilled in the art without making any inventive effort are within the scope of the present invention.
The treatment method of lead-zinc smelting waste acid comprises the following steps:
(1) Primary vulcanization: adding contaminated acid and a vulcanizing agent into a reactor for vulcanization, wherein the adding amount of the vulcanizing agent is As in the contaminated acid 3- And Tl - 1 to 1.2 times of the total molar concentration, and the ORP difference of the inlet and the outlet of the reactor is 10 to 100. In this step: the removal rates of arsenic and thallium respectively reach more than 95 percent and more than 90 percent, the partial removal of lead, the small removal of cadmium and the basic non-removal of zinc.
And performing solid-liquid separation after primary vulcanization to obtain a first filtrate and a first bottom mud.
(2) Secondary vulcanization: adding the first filtrate and a vulcanizing agent into a reactor, wherein the adding amount of the vulcanizing agent is Pb in the first filtrate 2- 、Cd 2- 、As 3- 、Tl - 1-1.2 times of total valence molar concentration, and the ORP difference of the inlet and the outlet of the reactor is 10-100. Cadmium is mainly removed in the step, the removal rate is more than 85%, zinc is not removed basically, and arsenic and thallium are removed basically and completely in the step. And performing solid-liquid separation after secondary vulcanization to obtain a second filtrate and second bottom mud. The cadmium sulfide slag contains more than 60% of cadmium.
(3) And (3) neutralization: lime milk is added into the second filtrate to react for 0.5-2h, the stirring speed is 60-100rpm in the reaction process, the pH value of the end point of the reaction liquid is controlled to be 3-5, and the third filtrate and the third bottom mud are obtained through solid-liquid separation.
And centrifuging the third sediment to obtain gypsum slag, and carrying out a toxicity leaching test on the gypsum slag according to hazardous waste identification standard leaching toxicity identification (GB 5085.3-2007), wherein cadmium in leaching liquid is less than 0.2mg/l (standard 1 mg/l), lead is less than 1mg/l (standard 5 mg/l), and arsenic is less than 1mg/l (standard 5 mg/l), so that the gypsum slag is general solid waste.
(4) Tertiary vulcanization: will beAdding the third filtrate and the vulcanizing agent into a reactor, wherein the inlet of the reactor is connected with the vulcanizing agent and a sodium hydroxide dosing pipe, and the adding amount of the vulcanizing agent is Zn in the third filtrate 2- The molar concentration is 1-1.2 times, the ORP difference value at the inlet and outlet of the reactor is 100-300, the pH value of the reaction liquid is regulated to 6-8, a flocculating agent is added after the reaction, the reaction liquid is sent into a thickening tank for sedimentation and clarification, a fourth supernatant fluid and fourth bottom mud are obtained, the fourth bottom mud is subjected to filter pressing by a filter press to obtain zinc sulfide slag, and the fourth supernatant fluid is discharged after reaching the standard.
The zinc sulfide slag contains more than 50% of zinc and more than 25% of sulfur.
In the production operation process, the method can control the addition amount of the vulcanizing agent according to the ORP difference value of the acid liquor, and realize the accurate and staged removal of different substances in the polluted acid. The inventors have also tried to judge the amount of vulcanizing agent added by ORP value, but the effect is not ideal, and the removal of impurities is not realized, or different impurities are removed simultaneously. Moreover, the ORP value of lead-zinc smelting waste acid fluctuates greatly, and if the ORP value is relied on to determine the dosage of vulcanizing agent in production, the vulcanization stripping can not be effectively realized at all. The inventor carries out a vulcanization experiment on lead-zinc smelting waste acid generated in a part of production sections, the change of the final ORP value can reach more than 1000, and because acidity, temperature, dissolved oxygen and chloride ions in a water body influence the ORP value, the addition amount of the vulcanizing agent is judged according to the ORP value, and the vulcanizing agent has no applicability in production and cannot provide guidance significance for production.
In order to more clearly illustrate the present invention, the following examples are provided.
Example 1
The waste acid of a certain lead-zinc smelting plant comprises the following components:
TABLE 1-1 lead zinc smelting dirty acid index case
| Element(s) | Sulfuric acid | Pb | Zn | Cd | As | Tl |
| Component (mg/l) | 21110 | 6.5 | 2351 | 196 | 850 | 2.6 |
Primary vulcanization treatment: preparing sodium hydrosulfide with concentration of 5% and sewage acid treatment capacity of 20m 3 And/h, carrying out As on lead-zinc smelting waste acid 3- 、Tl - Content detection according to As 3- And Tl - 1.2 times the total molar concentration (in the case of the ionic valences described below, the molar amounts of the ions in the corresponding valences were calculated only for trivalent arsenic and monovalent thallium), the addition of sodium bisulfide being 0.46m 3 And/h. The method comprises the steps of adding contaminated acid and sodium hydrosulfide into a reactor, wherein the volume of the reactor is 60 liters, the rotating speed of the reactor is 500rpm, the feeding pressure is 0.2MPa, ORP values at an inlet and an outlet of the reactor are 280 and 243 respectively, ORP difference value is 37, and after the reaction, the liquid automatically flows into a thickening tank to obtain first supernatant and first bottom mud, arsenic slag is obtained after the first bottom mud is subjected to filter pressing by a filter press, and the arsenic slag is disposed according to dangerous waste. The first supernatant was analyzed to obtain the removal rate of each substance as shown in tables 1 to 2.
Tables 1 to 2 removal rate of the first stage vulcanization treatment of each substance
| Element(s) | Sulfuric acid | Pb | Zn | Cd | As | Tl |
| Dirty acid (mg/l) | 21110 | 6.5 | 2351 | 196 | 850 | 2.6 |
| First supernatant (mg/l) | 20190 | 2.1 | 2325 | 175 | 14.6 | 0.14 |
| First-stage vulcanization removal rate | 67.69％ | 1.11％ | 10.71％ | 98.28％ | 94.62％ |
Secondary vulcanization treatment: the concentration of sodium hydrosulfide was 5% based on Pb in the first supernatant 2- 、Cd 2- 、As 3- And Tl - Calculated as 1.2 times of the total molar concentration, the addition amount of sodium hydrosulfide is 0.05m 3 And/h. The first supernatant was subjected to a flow rate of 20m 3 /h, sodium hydrosulfide at a flow rate of 0.05m 3 And (3) introducing the mixture/h into a reactor, wherein the volume of the reactor is 60 liters, the rotating speed of the reactor is 500rpm, the feeding pressure is 0.2MPa, the ORP value at the inlet and outlet of the reactor is 240 and 201 respectively, the ORP difference value is 39, the reacted liquid automatically flows into a thickening tank to obtain a second supernatant fluid and a second bottom mud, and the second bottom mud is subjected to filter pressing by a filter press to obtain cadmium sulfide slag (the cadmium dry basis content is 63.1 percent), so that the cadmium sulfide slag can be recycled. The second supernatant was analyzed to obtain the removal rate of each substance as shown in tables 1 to 3.
Tables 1 to 3 removal rate of the secondary vulcanization treatment of each substance
| Project | Sulfuric acid | Pb | Zn | Cd | As | Tl |
| Dirty acid (mg/l) | 21110 | 6.5 | 2351 | 196 | 850 | 2.6 |
| First supernatant (mg/l) | 20190 | 2.1 | 2325 | 175 | 14.6 | 0.14 |
| Second supernatant (mg/l) | 19874 | 0.97 | 2306 | 0.32 | 0.1 | 0.013 |
| Secondary vulcanization removal rate | 17.38％ | 0.81％ | 89.12％ | 1.71％ | 4.88％ | |
| Cumulative removal rate | 85.08％ | 1.91％ | 99.84％ | 99.99％ | 99.50％ |
And (3) neutralization treatment: adding the second supernatant and 10% lime milk into a neutralization reaction tank, stirring at a speed of 72rpm, adjusting the amount of lime milk, controlling the pH value of the neutralization effluent to be 3-5, allowing the reacted liquid to flow into a thickening tank to obtain a third supernatant and a third bottom mud, centrifuging the third bottom mud to obtain gypsum slag, and performing toxicity leaching experiments to show that the leached liquid cadmium: 0.17mg/l, lead: 0.96mg/l, arsenic: 0.51mg/l, belongs to common solid waste, and can be recycled to cement factories.
And (3) tertiary vulcanization treatment: preparing sodium sulfide with concentration of 5% and treating the third supernatant with treatment capacity of 20m 3 According to Zn in the third supernatant 2- Calculated as 1.2 times of the total molar concentration, the addition amount of sodium sulfide is 0.92m 3 And/h. Meanwhile, the inlet of the reactor is connected with a sulfuric acid and sodium hydroxide dosing pipe, and the pH value of the effluent of the reactor is regulated to be 6-8; the volume of the reactor is 60L, the rotating speed of the reactor is 500rpm, the feeding pressure is 0.2MPa, the ORP values at the inlet and outlet of the reactor are 159-29 respectively, the ORP difference value is 188, the reacted liquid enters a thickening tank after adding a flocculating agent, a fourth supernatant fluid and a fourth bottom mud are obtained, and zinc sulfide slag (zinc dry basis content is 56.3%) is obtained after the fourth bottom mud is subjected to filter pressing by a filter press, and resources are recovered. And measuring and analyzing the fourth supernatant index to obtain the removal rate of each substance as shown in tables 1-4.
Tables 1 to 4 removal rate of three-stage vulcanization treatment of each substance
| Project | pH | Pb | Zn | Cd | As | Tl |
| Dirty acid (mg/l) | 21110 | 6.5 | 2351 | 196 | 850 | 2.6 |
| Fourth supernatant (mg/l) | 7.2 | 0.26 | 0.82 | 0.04 | 0.07 | 0.005 |
| Three-stage vulcanization removal rate | 10.92％ | 98.05％ | 0.14％ | 0.00％ | 0.31％ | |
| Cumulative removal rate | 96.00％ | 99.97％ | 99.98％ | 99.99％ | 99.81％ |
The method comprises the steps of adding a reagent by referring to ORP difference values of an inlet and an outlet of a reactor, wherein when the total molar quantity of the removed impurities of the vulcanizing agent is 1.2 times of that of each step, the ORP difference value of primary vulcanization is 37, the ORP difference value of subsequent primary vulcanization is controlled to be 37+/-10, when the ORP difference value is lower than 27, the adding quantity of the vulcanizing agent is increased, when the ORP difference value is higher than 47, the adding quantity of the vulcanizing agent is reduced, and the adding quantity of the vulcanizing agent is controlled to be 39+/-10 and 188+/-10 respectively.
The heavy metal content in the polluted acid cannot be detected in real time in the production process, the adding amount of the vulcanizing agent is difficult to control directly according to the impurity content in the production process, but in a certain production period, the fluctuation of the ORP value of the acid is small, the ORP difference value has a linear relation with the mol amount of the impurity, the adding amount of the vulcanizing agent is controlled through the ORP difference value, the impurity content in the polluted acid is measured regularly, the adding amount of the vulcanizing agent is finely adjusted and corrected according to the impurity measurement data, and then the adding amount of the vulcanizing agent is controlled according to the ORP value after adjustment of the adding amount of the vulcanizing agent. The method can realize the accurate control of the addition amount of the vulcanizing agent in the production process, and has the advantages of stable control, stable heavy metal stripping rate and no solid waste gypsum production through verification of production practice.
Example 2
The waste acid of a certain lead smelting plant comprises the following components:
TABLE 2-1 lead zinc smelting dirty acid index case
| Element(s) | Sulfuric acid | Pb | Zn | Cd | As | Tl |
| Component (mg/l) | 35700 | 10.8 | 578 | 489 | 793 | 7.8 |
Primary vulcanization treatment: preparing sodium hydrosulfide with concentration of 6% and sewage acid treatment capacity of 15m 3 Per hour, according to As 3- And Tl - Calculated as 1.2 times of the total molar concentration, the addition amount of sodium hydrosulfide is 0.32m 3 And/h. The contaminated acid was fed at a flow rate of 15m 3 /h, sodium hydrosulfide at a flow rate of 0.32m 3 Adding the mixture into a reactor at a speed of 600rpm and a reaction pressure of 0.1MPa, wherein the ORP values at the inlet and the outlet of the reactor are respectively 365 and 322, ORP difference of 43. And allowing the reacted liquid to flow into a thickening tank automatically to obtain a first supernatant and a first bottom mud, and performing filter pressing on the first bottom mud by a filter press to obtain arsenic slag, and disposing according to dangerous waste. The first supernatant was analyzed to obtain the removal rate of each substance as shown in Table 2-2.
Table 2-2 removal Rate of Primary vulcanization treatment of substances
| Element(s) | Sulfuric acid | Pb | Zn | Cd | As | Tl |
| Dirty acid (mg/l) | 35700 | 10.8 | 578 | 489 | 793 | 7.8 |
| First supernatant (mg/l) | 34890 | 4.3 | 568 | 429 | 24 | 0.63 |
| First-stage vulcanization removal rate | 60.2％ | 1.7％ | 12.3％ | 97.0％ | 91.9％ |
Secondary vulcanization treatment: sodium hydrosulfide concentration was 6% based on Pb in the first supernatant 2- 、Cd 2- 、As 3- And Tl - Calculated as 1.2 times of the total molar concentration, the addition amount of sodium hydrosulfide is 0.09m 3 And/h. The first supernatant was subjected to a flow rate of 15m 3 /h, sodium hydrosulfide at a flow rate of 0.09m 3 And (3) introducing the mixture/h into a reactor, wherein the volume of the reactor is 60L, the rotating speed of the reactor is 600rpm, the reaction pressure is 0.1MPa, the ORP values at the inlet and outlet of the reactor are 326 and 277 respectively, the ORP difference value is 49, the reacted liquid automatically flows into a thickening tank to obtain a second supernatant fluid and a second bottom mud, and the second bottom mud is subjected to filter pressing by a filter press to obtain cadmium sulfide slag (the cadmium dry basis content is 65.3 percent), so that the cadmium sulfide slag can be recycled. The second supernatant was analyzed to obtain the removal rate of each substance as shown in tables 2 to 3.
Tables 2 to 3 removal rate of the secondary vulcanization treatment of each substance
| Project | Sulfuric acid | Pb | Zn | Cd | As | Tl |
| Dirty acid (mg/l) | 35700 | 10.8 | 578 | 489 | 793 | 7.8 |
| First supernatant (mg/l) | 34890 | 4.3 | 568 | 429 | 24 | 0.63 |
| Second supernatant (mg/l) | 34050 | 1.28 | 556 | 0.69 | 0.21 | 0.053 |
| Secondary vulcanization removal rate | 27.96％ | 2.08％ | 87.59％ | 3.00％ | 7.40％ | |
| Cumulative removal rate | 88.15％ | 3.81％ | 99.86％ | 99.97％ | 99.32％ |
And (3) neutralization treatment: the second supernatant and 10% lime milk react to neutralize the reaction tank, the stirring speed is 72rpm, the lime milk amount is regulated, the pH value of the neutralized effluent is controlled to be 3-5, the reacted liquid automatically flows into a thickening tank to obtain a third supernatant and a third bottom mud, the third bottom mud is centrifuged to obtain gypsum slag, and toxicity leaching experiments show that the gypsum slag belongs to common solid waste and can be recycled to cement factories.
And (3) tertiary vulcanization treatment: preparing sodium sulfide with concentration of 2.5% and treating third supernatant with treatment capacity of 15m 3 According to Zn in the third supernatant 2- Calculated as 1.2 times of the total molar concentration, the addition amount of sodium sulfide is 0.92m 3 And/h. The third supernatant was subjected to a flow rate of 20m 3 /h, sodium sulfide at a flow rate of 0.92m 3 Introducing the wastewater into a reactor, connecting sulfuric acid and sodium hydroxide dosing pipes at the inlet of the reactor, and adjusting the pH value of the effluent of the reactor to 6-8; the volume of the reactor is 60L, the rotating speed of the reactor is 600rpm, the reaction pressure is 0.1MPa, the ORP values at the inlet and outlet of the reactor are 206-35 respectively, the ORP difference value is 241, the reacted liquid is added with a flocculating agent and then automatically flows into a thickening tank to obtain fourth supernatant and fourth bottom mud, and the fourth bottom mud is subjected to filter pressing by a filter press to obtain zinc sulfide slag (the zinc dry basis content is 51.2 percent), so that the zinc sulfide slag can be recycled. Analyzing the fourth supernatant fluid index to obtain the removal of each substanceThe removal rates are shown in tables 2-4.
Tables 2 to 4 removal rate of three-stage vulcanization treatment of each substance
| Project | pH | Pb | Zn | Cd | As | Tl |
| Dirty acid (mg/l) | 35700 | 10.8 | 578 | 489 | 793 | 7.8 |
| Third supernatant (mg/l) | 3.9 | 1.03 | 489 | 0.46 | 0.18 | 0.047 |
| Fourth supernatant (mg/l) | 6.8 | 0.13 | 0.46 | 0.038 | 0.09 | 0.01 |
| Three-stage vulcanization removal rate | 10.65％ | 96.11％ | 0.13％ | 0.02％ | 0.55％ | |
| Cumulative removal rate | 98.80％ | 99.92％ | 99.99％ | 99.99％ | 99.87％ |
Because the heavy metal content in the polluted acid cannot be detected in real time in the production process, the reagent is added by referring to the ORP difference value at the inlet and outlet of the reactor, when the vulcanizing agent is added according to 1.2 times of the total molar quantity of the removed impurities, the ORP difference value of the primary vulcanization is 43, the ORP difference value of the subsequent primary vulcanization is 43+/-10, when the ORP difference value is lower than 33, the sodium hydrosulfide addition amount is increased, when the ORP difference value is higher than 53, the sodium hydrosulfide addition amount is reduced, and the ORP difference values of the secondary vulcanizing agent and the tertiary vulcanizing agent are 49+/-10 and 241+/-10 respectively.
Remarks: when the invention is not specifically described, the percentage amounts refer to mass percentage amounts.
Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as defined by the appended claims.
Claims (6)
1. The method for treating lead-zinc smelting waste acid is characterized by comprising the following steps of:
(1) First-stage vulcanizing, namely adding the contaminated acid and a vulcanizing agent into a reactor for vulcanization, wherein the adding amount of the vulcanizing agent is As in the contaminated acid 3- And Tl - 1 to 1.2 times of the total molar concentration, wherein the ORP difference value at the inlet and outlet of the reactor is 10 to 100, so that arsenic and thallium are precipitated; after vulcanization, carrying out solid-liquid separation to obtain a first filtrate and a first bottom mud;
(2) Secondary desulfurization, adding the first filtrate and a vulcanizing agent into a reactor, wherein the adding amount of the vulcanizing agent is Pb in the first filtrate 2- 、Cd 2- 、As 3- And Tl - 1-1.2 times of total molar concentration, wherein the ORP difference value at the inlet and outlet of the reactor is 10-100, so that cadmium is vulcanized and precipitated, and solid-liquid separation is carried out after vulcanization to obtain second filtrate and second bottom mud;
(3) And (3) neutralizing, namely adding lime cream into the second filtrate, controlling the pH value of the reaction end point to be 3-5, and carrying out solid-liquid separation to obtain a third filtrate and gypsum bottom mud.
2. The method for treating lead-zinc smelting waste acid according to claim 1, further comprising the step of (4) tertiary sulfidizing, wherein the third filtrate and sulfidizing agent are added into the reactor, and the adding amount of sulfidizing agent is Zn in the third filtrate 2- 1 to 1.2 times of the molar concentration, the ORP difference value at the inlet and outlet of the reactor is 50 to 200, the pH value of the reaction material is adjusted to 6 to 8, and the solid and the liquid are separated after the reaction is finished, so as to obtain fourth filtrate and fourth bottom sludge.
3. The method for treating lead-zinc smelting waste acid according to claim 1 or 2, wherein in the step (3), the reaction time of the second filtrate and lime milk is 0.5-2 hours, and the stirring speed is 60-100rpm.
4. The method for treating lead-zinc smelting waste acid according to claim 3, wherein the vulcanizing agent is one or more of hydrogen sulfide, sodium sulfide and sodium hydrosulfide.
5. The method for treating lead-zinc smelting contaminated acid according to claim 2, wherein the reactor pressure is 0.1-0.3MPa, the stirring speed is 500-800rpm, and the reaction time is 3-60s.
6. The method for treating lead-zinc smelting waste acid according to claim 2, wherein in the step (4), a flocculating agent is added after three-stage vulcanization and then liquid-solid separation is performed.
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