CN115385507B - Pretreatment method for co-treatment of sulfuric acid system waste etching solution and water treatment chromium-containing sludge - Google Patents
Pretreatment method for co-treatment of sulfuric acid system waste etching solution and water treatment chromium-containing sludge Download PDFInfo
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- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 title claims abstract description 132
- 239000011651 chromium Substances 0.000 title claims abstract description 112
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 title claims abstract description 108
- 229910052804 chromium Inorganic materials 0.000 title claims abstract description 108
- 238000005530 etching Methods 0.000 title claims abstract description 76
- 239000002699 waste material Substances 0.000 title claims abstract description 74
- 239000010802 sludge Substances 0.000 title claims abstract description 62
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 27
- 238000002203 pretreatment Methods 0.000 title claims abstract description 18
- 238000011278 co-treatment Methods 0.000 title claims abstract description 17
- 239000000243 solution Substances 0.000 claims abstract description 84
- 239000002253 acid Substances 0.000 claims abstract description 29
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims abstract description 28
- 238000001914 filtration Methods 0.000 claims abstract description 25
- 239000010949 copper Substances 0.000 claims abstract description 24
- 239000000706 filtrate Substances 0.000 claims abstract description 23
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910052802 copper Inorganic materials 0.000 claims abstract description 22
- 238000004090 dissolution Methods 0.000 claims abstract description 20
- 239000002002 slurry Substances 0.000 claims abstract description 18
- 238000001704 evaporation Methods 0.000 claims abstract description 17
- 239000002893 slag Substances 0.000 claims abstract description 14
- 239000011259 mixed solution Substances 0.000 claims abstract description 12
- 239000002994 raw material Substances 0.000 claims abstract description 10
- 239000003957 anion exchange resin Substances 0.000 claims abstract description 8
- 238000003723 Smelting Methods 0.000 claims abstract description 7
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 claims abstract description 6
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 claims abstract description 6
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 5
- MOUPNEIJQCETIW-UHFFFAOYSA-N lead chromate Chemical compound [Pb+2].[O-][Cr]([O-])(=O)=O MOUPNEIJQCETIW-UHFFFAOYSA-N 0.000 claims abstract description 5
- 230000003472 neutralizing effect Effects 0.000 claims abstract description 5
- 239000007788 liquid Substances 0.000 claims description 40
- PXLIDIMHPNPGMH-UHFFFAOYSA-N sodium chromate Chemical compound [Na+].[Na+].[O-][Cr]([O-])(=O)=O PXLIDIMHPNPGMH-UHFFFAOYSA-N 0.000 claims description 29
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims description 15
- 239000013078 crystal Substances 0.000 claims description 10
- KPVWDKBJLIDKEP-UHFFFAOYSA-L dihydroxy(dioxo)chromium;sulfuric acid Chemical compound OS(O)(=O)=O.O[Cr](O)(=O)=O KPVWDKBJLIDKEP-UHFFFAOYSA-L 0.000 claims description 10
- 239000004568 cement Substances 0.000 claims description 9
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims description 8
- 238000002425 crystallisation Methods 0.000 claims description 8
- 230000008025 crystallization Effects 0.000 claims description 8
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 claims description 7
- XEMZLVDIUVCKGL-UHFFFAOYSA-N hydrogen peroxide;sulfuric acid Chemical compound OO.OS(O)(=O)=O XEMZLVDIUVCKGL-UHFFFAOYSA-N 0.000 claims description 7
- 229910052938 sodium sulfate Inorganic materials 0.000 claims description 7
- 235000011152 sodium sulphate Nutrition 0.000 claims description 7
- 230000008020 evaporation Effects 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- 230000003647 oxidation Effects 0.000 claims description 3
- 238000007254 oxidation reaction Methods 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 2
- 239000000463 material Substances 0.000 claims 1
- 238000004064 recycling Methods 0.000 abstract description 6
- 238000002360 preparation method Methods 0.000 abstract 1
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical group [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 18
- 238000000034 method Methods 0.000 description 13
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 12
- 230000000052 comparative effect Effects 0.000 description 12
- 238000000926 separation method Methods 0.000 description 9
- 238000006243 chemical reaction Methods 0.000 description 8
- 239000000047 product Substances 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 238000012360 testing method Methods 0.000 description 7
- 229910001870 ammonium persulfate Inorganic materials 0.000 description 6
- 238000002386 leaching Methods 0.000 description 6
- 230000000593 degrading effect Effects 0.000 description 4
- 239000002440 industrial waste Substances 0.000 description 4
- 239000012528 membrane Substances 0.000 description 4
- 238000001238 wet grinding Methods 0.000 description 4
- 208000005156 Dehydration Diseases 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 230000018044 dehydration Effects 0.000 description 3
- 238000006297 dehydration reaction Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 2
- 235000011130 ammonium sulphate Nutrition 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000007711 solidification Methods 0.000 description 2
- 230000008023 solidification Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000711 cancerogenic effect Effects 0.000 description 1
- 229910001430 chromium ion Inorganic materials 0.000 description 1
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical compound [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 description 1
- 229940125368 controlled substance Drugs 0.000 description 1
- 239000000599 controlled substance Substances 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000001784 detoxification Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000011549 displacement method Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000008394 flocculating agent Substances 0.000 description 1
- 229910052602 gypsum Inorganic materials 0.000 description 1
- 239000010440 gypsum Substances 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G37/00—Compounds of chromium
- C01G37/14—Chromates; Bichromates
-
- 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
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/048—Purification of waste water by evaporation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/722—Oxidation by peroxides
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
- C02F2001/422—Treatment of water, waste water, or sewage by ion-exchange using anionic exchangers
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F2001/5218—Crystallization
-
- 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
- C02F2101/101—Sulfur compounds
-
- 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
- C02F2101/20—Heavy metals or heavy metal compounds
-
- 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
- C02F2101/20—Heavy metals or heavy metal compounds
- C02F2101/22—Chromium or chromium compounds, e.g. chromates
-
- 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
- C02F2101/30—Organic compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/16—Nature of the water, waste water, sewage or sludge to be treated from metallurgical processes, i.e. from the production, refining or treatment of metals, e.g. galvanic wastes
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- Chemical & Material Sciences (AREA)
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- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Inorganic Chemistry (AREA)
- ing And Chemical Polishing (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Abstract
The invention discloses a pretreatment method for the co-treatment of sulfuric acid system waste etching solution and water treatment chromium-containing sludge, which comprises the following steps: s1: preparing chromium-containing sludge into sludge slurry; s2: carrying out acid dissolution on the sludge slurry by using waste etching solution containing sulfuric acid; s3: filtering the mixed solution after acid dissolution to obtain chromium-containing filtrate and filter residues, and dehydrating the filter residues to be comprehensively utilized by taking the filter residues as a substitute raw material; s4: adding a neutralizing agent into the chromium-containing filtrate to adjust the pH value and filtering to obtain chromic acid and copper-rich slag, wherein the copper-rich slag can be used for recovering metallic copper through smelting; s5: adding strong-alkaline anion exchange resin and hydrogen peroxide into chromic acid solution, evaporating and crystallizing to obtain the raw material for preparing chrome yellow. The invention discloses a pretreatment method for the co-treatment of sulfuric acid system waste etching solution and water treatment chromium-containing sludge, and the pretreatment method can be used for recycling chromium resources in the waste acid etching solution and the water treatment chromium-containing sludge, so that the purpose of waste preparation by waste is achieved.
Description
Technical Field
The invention relates to the technical field of industrial waste recycling, in particular to a pretreatment method for the co-treatment of sulfuric acid system waste etching solution and water treatment chromium-containing sludge.
Background
Chromium occupies a significant position in industrial production, but the reserves of the chromium resources are not abundant, and particularly, china belongs to countries with poor chromium resources, and chromium ores mainly depend on import, so that the reasonable and effective utilization of the chromium resources and the recycling of the chromium resources in industrial wastes are the most important problems at present.
With the development of the electrochemical industry, the productivity is continuously enlarged, and the discharge amount of waste acid etching liquid and chromium-containing wastewater generated in the electroplating industry is gradually increased year by year. Because chromium has great harm to the environment and can accumulate in the human body, has carcinogenic effect, and has strict standards on chromium-containing wastewater and sludge in China, the two wastes need corresponding disposal modes.
At present, the main methods for treating waste acidic etching liquid in China are chemical methods (an electrolytic method and a displacement method) for recovering valuable metals in waste liquid or traditional alkali addition for neutralization to become solid waste. Wherein the chemical method has complex process, incomplete recovery, insignificant economic benefit and secondary pollutant generation. The traditional method has the problems that the total amount of waste emission is increased, valuable metals cannot be recycled and the like although the cost is lower.
At present, the main method for disposing the chromium-containing sludge is a solidification method, hexavalent chromium in the chromium-containing sludge is reduced into trivalent chromium with lower toxicity through wet detoxification, then alkali liquor and flocculating agent are added, solid-liquid separation is carried out, and filter residues are added with stabilizing agent and cement for solidification and then landfill is carried out. The method has complex treatment process and faces the problems of sludge compatibilization and incapability of recycling metals.
Disclosure of Invention
The invention discloses a pretreatment method for the co-treatment of sulfuric acid system waste etching solution and water treatment chromium-containing sludge, which reduces the problems of secondary pollutant discharge, land occupation resource, environmental pollution and the like when the waste acid etching solution and the chromium-containing sludge are treated, and simultaneously recovers the chromium resource in the waste acid etching solution and the water treatment chromium-containing sludge, thereby achieving the purpose of waste disposal.
In order to achieve the above object, the technical scheme of the present invention is as follows:
a pretreatment method for co-treatment of sulfuric acid system waste etching liquid and water treatment chromium-containing sludge comprises the following steps:
s1: uniformly mixing chromium-containing sludge and water to obtain sludge;
s2: acid-dissolving the sludge slurry prepared in the step S1 by using sulfuric acid-containing waste etching liquid, wherein the acid-dissolving temperature is 55-65 ℃, and the acid-dissolving time is 2-4 hours to obtain a mixed liquid, and the mass ratio of chromium in the chromium-containing sludge to sulfuric acid in the sulfuric acid-containing waste etching liquid is 1: (7.5-9); preferably, the acid dissolution temperature is 60 ℃;
the reaction is as follows: 2Cr (OH) 3 +3H 2 SO 4 →Cr 2 (SO 4 ) 3 +6H 2 O；
S3: filtering the mixed solution prepared in the step S2 to obtain chromium-containing filtrate and filter residues, wherein the filter residues can be comprehensively utilized as a substitute raw material by a cement kiln after dehydration;
s4: adding a neutralizing agent into the chromium-containing filtrate obtained in the step S3, adjusting the pH value to 14, and then filtering to obtain a chromium-containing filtrate containing CrO 2 - The solution and the copper-rich slag, wherein the copper-rich slag can be used for recovering metallic copper through smelting; preferably, the neutralizing agent is sodium hydroxide;
the reaction is as follows: cu (Cu) 2+ +2OH - →Cu(OH) 2 ↓
Cr 3+ +3OH - →Cr(OH) 3 ↓
Cr(OH) 3 +OH - →CrO 2 - +2H 2 O；
S5: to step S4, crO is added 2 - Adding strong alkaline anion exchange resin and 30% hydrogen peroxide into the solution, adding CrO 2 - Oxidation to CrO 4 2- Then evaporating and crystallizing to obtain chromic acidThe sulfate content in the sodium product is between 0.2 percent and 0.4 percent, and the sodium chromate content is more than 98 percent and accords with the HG/T4312-2012 standard of industrial sodium chromate, thus being used as the raw material for preparing chrome yellow.
The reaction is as follows: 2CrO 2 - +3H 2 O 2 +2OH - →2CrO 4 2- +4H 2 O
Pb 2+ +CrO 4 2- →PbCrO 4 ↓。
By adopting the technical scheme, as the chromic acid-sulfuric acid with the sulfuric acid concentration of 7-12 percent, the etching solution of the hydrogen peroxide-sulfuric acid system and the chromium-containing sludge are mixed and dissolved in the mass ratio of 1 (7.5-9), the ammonium persulfate etching solution with lower sulfuric acid concentration can better leach chromium in the chromium sludge and convert redundant sulfuric acid in the etching solution into calcium sulfate precipitation. The chromium content of the filter residue after acid dissolution and filtration reaches the standard, and the dehydrated calcium sulfate content is more than 75 percent, so that the filter residue can be used as a substitute raw material of a cement kiln. And adding a neutralizing agent into the acid-dissolved filtrate to adjust the pH value to 14, controlling the reaction temperature to 10 ℃, removing metal ions by precipitation, and reversely dissolving chromium ions into the solution to realize impurity removal and recovery. Removing sulfate radical from the solution by anion exchange resin, adding hydrogen peroxide with 2.5-3 times of chromium mass in the solution, and adding CrO under strong alkaline condition 2 - Oxidation to CrO 4 2- At the same time, a small amount of organic matters remained in the etching solution can be oxidized and degraded. And finally evaporating and crystallizing for multiple times, and evaporating and separating out sodium sulfate remained in the solution to obtain a sodium chromate product with the sulfate content of 0.2-0.4%.
Further, the mass fraction of sulfuric acid in the sulfuric acid-containing waste etching solution is 7% -12%.
Further, the content of total chromium in the sulfuric acid-containing waste etching solution is 0.1-60g/L, and the density is 1.1-1.3g/cm 3 The pH is less than 1.
Further, the sulfuric acid-containing waste etching liquid is selected from chromic acid-sulfuric acid system waste etching liquid or hydrogen peroxide-sulfuric acid system waste etching liquid;
the chromic acid-sulfuric acid system waste etching solution contains 1-3 wt% of chromic acid and 7-10 wt% of sulfuric acid;
the hydrogen peroxide-sulfuric acid system waste etching liquid contains less than 3wt% of hydrogen peroxide and 8-12 wt% of sulfuric acid.
Further, the mass fraction of chromium in the chromium-containing sludge is 5-13%
Further, in the step S3, the filter residue contains more than or equal to 75wt% of calcium sulfate.
Further, in step S5, the hydrogen peroxide and the CrO-containing solution are mixed 2 - The mass ratio of chromium in the solution is (2.5-3): 1.
further, in step S4, the temperature is controlled to 5-10 ℃ during the process of adjusting the pH to 14.
Further, the sodium chromate crystal contains 0.2 to 0.4 percent of sulfate by mass percent.
Further, the operation of the evaporative crystallization is as follows: will contain CrO 4 2- And heating and evaporating the solution, filtering after crystallization occurs, crystallizing and separating out residual sodium sulfate, then performing secondary evaporation on the filtrate obtained by filtering, and repeating the filtering steps to obtain sodium chromate crystals with the mass fraction of 84.0% -85.6% of sodium chromate.
The pretreatment method for the co-treatment of the sulfuric acid system waste etching solution and the water treatment chromium-containing sludge has the beneficial effects that:
firstly, the method for preparing waste by waste adopts water to treat chromium sludge and waste etching solution containing sulfuric acid to cooperatively treat, and simultaneously precipitates heavy metals in the waste acid etching solution while preparing sodium chromate products, so that residual organic matters are degraded, the treated chromium sludge can be used as a cement kiln to replace raw materials, the recycling utilization of industrial wastes is realized, and the landfill volume and the treatment cost are reduced.
Secondly, the sulfate content in the sodium chromate product obtained by the invention is between 0.2 and 0.4 percent, and the sodium chromate content is more than 98 percent and accords with the HG/T4312-2012 standard of industrial sodium chromate, so that the sodium chromate product can be used as a raw material for preparing chrome yellow, and the economic effect is maximized.
Thirdly, the invention refers to the waste acid etching liquid through the chromium in the chromium-containing sludge and consumes the acid in the waste acid etching liquid, copper in the waste acid etching liquid is precipitated by adjusting the pH value by NaOH, and the chromium is reversely dissolved into the liquid because of excessive alkali, thus the effect of reducing impurities is obtained.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Examples
Example 1
A pretreatment method for co-treatment of sulfuric acid system waste etching liquid and water treatment chromium-containing sludge comprises the following steps:
s1: adding 10kg of water into 100kg of chromium-containing sludge, and wet-grinding into slurry by a wet ball mill to obtain sludge; the mass fraction of chromium in the chromium-containing sludge is 5 percent according to GB/T36690-2018 standard;
s2: conveying the sludge slurry prepared in the step S1 into a reaction kettle with stirring through a slurry pump, and then adding 536kg of sulfuric acid-containing waste etching solution for acid dissolution, wherein the acid dissolution temperature is 55 ℃, and the mixed solution is obtained after 2 hours of acid dissolution; the mass ratio of chromium in the sludge slurry to sulfuric acid in the sulfuric acid-containing waste etching solution is 1:7.5;
the sulfuric acid-containing waste etching solution is hydrogen peroxide-sulfuric acid waste etching solution, and the hydrogen peroxide-sulfuric acid waste etching solution contains 1.5wt% of hydrogen peroxide and 7wt% of sulfuric acid;
s3: performing solid-liquid separation on the mixed solution prepared in the step S2 through a high-pressure membrane filter press to obtain chromium-containing filtrate and filter residues;
s4: adding NaOH solution into the chromium-containing filtrate obtained in the step S3, stirring, adjusting the pH value to 14, reacting at 10 ℃, and then carrying out solid-liquid separation to obtain NaCrO 2 The solution and copper-rich slag, the copper-rich slag can recycle metallic copper through smelting;
s5: to the NaCrO prepared in step S4 2 Adding strong alkaline anion exchange resin into the solution to remove sulfate radical, adding 42kg hydrogen peroxide with mass concentration of 30%, degrading residual organic matters in the solution and making CrO 2 - Fully oxidized to CrO 4 2- Then will contain CrO 4 2- And heating and evaporating the solution, filtering after crystallization occurs, crystallizing and separating out residual sodium sulfate, then performing secondary evaporation on the filtrate obtained by filtering, and repeating the filtering step for 3 times to obtain sodium chromate crystals.
Example 2:
a pretreatment method for co-treatment of sulfuric acid system waste etching liquid and water treatment chromium-containing sludge comprises the following steps:
s1: adding 15kg of water into 100kg of chromium-containing sludge, and wet-grinding into slurry by a wet ball mill to obtain sludge; the mass fraction of chromium in the chromium-containing sludge is 8 percent according to GB/T36690-2018 standard;
s2: conveying the sludge slurry prepared in the step S1 into a reaction kettle with stirring through a slurry pump, and then adding 600kg of sulfuric acid-containing waste etching solution for acid dissolution, wherein the acid dissolution temperature is 60 ℃, and the mixed solution is obtained after 3 hours of acid dissolution; the mass ratio of the chromium in the chromium-containing sludge to the sulfuric acid in the sulfuric acid-containing waste etching solution is 1:9;
the sulfuric acid-containing waste etching solution is chromic acid-sulfuric acid system waste etching solution, and the chromic acid-sulfuric acid system waste etching solution contains 3.8wt% chromic acid and 12wt% sulfuric acid;
s3: performing solid-liquid separation on the mixed solution prepared in the step S2 through a high-pressure membrane filter press to obtain chromium-containing filtrate and filter residues;
s4: adding NaOH solution into the chromium-containing filtrate obtained in the step S3, stirring, adjusting the pH value to 14, reacting at 5 ℃, and then carrying out solid-liquid separation to obtain NaCrO 2 The solution and copper-rich slag, the copper-rich slag can recycle metallic copper through smelting;
s5: to the NaCrO prepared in step S4 2 Adding strong alkaline anion exchange resin into the solution to remove sulfate radical, adding 244kg hydrogen peroxide with mass concentration of 30%, degrading residual organic matters in the solution and making CrO 2 - Fully oxidized to CrO 4 2- Then will containWith CrO 4 2- And heating and evaporating the solution, filtering after crystallization occurs, crystallizing and separating out residual sodium sulfate, then performing secondary evaporation on the filtrate obtained by filtering, and repeating the filtering step for 3 times to obtain sodium chromate crystals.
Example 3:
a pretreatment method for co-treatment of sulfuric acid system waste etching liquid and water treatment chromium-containing sludge comprises the following steps:
s1: adding 20kg of water into 100kg of chromium-containing sludge, and wet-grinding into slurry by a wet ball mill to obtain sludge; the mass fraction of chromium in the chromium-containing sludge is 10% according to GB/T36690-2018 standard test;
s2: conveying the sludge slurry prepared in the step S1 into a reaction kettle with stirring through a slurry pump, and then adding 982kg of sulfuric acid-containing waste etching solution for acid dissolution, wherein the acid dissolution temperature is 65 ℃, and the mixed solution is obtained after acid dissolution for 4 hours; the mass ratio of chromium in the chromium-containing sludge to sulfuric acid in the sulfuric acid-containing waste etching solution is 1:9;
the sulfuric acid-containing waste etching solution is chromic acid-sulfuric acid system waste etching solution, and the chromic acid-sulfuric acid system waste etching solution contains 1.7 weight percent of chromic acid and 8.2 weight percent of sulfuric acid;
s3: performing solid-liquid separation on the mixed solution prepared in the step S2 through a high-pressure membrane filter press to obtain chromium-containing filtrate and filter residues;
s4: adding NaOH solution into the chromium-containing filtrate obtained in the step S3, stirring, adjusting the pH value to 14, reacting at 8 ℃, and then carrying out solid-liquid separation to obtain NaCrO 2 The solution and copper-rich slag, the copper-rich slag can recycle metallic copper through smelting;
s5: to the NaCrO prepared in step S4 2 Adding strong-alkaline anion exchange resin into the solution to remove sulfate radical, adding 558kg hydrogen peroxide with mass concentration of 30%, degrading residual organic matters in the solution and making CrO 2 - Fully oxidized to CrO 4 2- Then will contain CrO 4 2- And heating and evaporating the solution, filtering after crystallization occurs, crystallizing and separating out residual sodium sulfate, then performing secondary evaporation on the filtrate obtained by filtering, and repeating the filtering step for 3 times to obtain sodium chromate crystals.
Comparative example
Comparative example 1:
s1: adding 15kg of water into 100kg of chromium-containing sludge, and wet-grinding into slurry by a wet ball mill to obtain sludge; the mass fraction of chromium in the chromium-containing sludge is 8 percent according to GB/T36690-2018 standard;
s2: conveying the sludge slurry prepared in the step S1 into a reaction kettle with stirring through a slurry pump, and then adding 1412kg of ammonium persulfate waste etching solution for acid dissolution, wherein the acid dissolution temperature is 60 ℃, and the mixed solution is obtained after 3 hours of acid dissolution; the mass ratio of the chromium in the chromium-containing sludge to the sulfuric acid in the sulfuric acid-containing waste etching solution is 1:9;
the sulfuric acid-containing waste etching liquid is ammonium persulfate system waste etching liquid, and the ammonium persulfate system waste etching liquid contains 5.1wt% of sulfuric acid and 6.8 wt% of ammonium sulfate;
s3: performing solid-liquid separation on the mixed solution prepared in the step S2 through a high-pressure membrane filter press to obtain chromium-containing filtrate and filter residues;
s4: adding NaOH solution into the chromium-containing filtrate obtained in the step S3, stirring, adjusting the pH value to 14, reacting at 5 ℃, and then carrying out solid-liquid separation to obtain NaCrO 2 The solution and copper-rich slag, the copper-rich slag can recycle metallic copper through smelting;
s5: to the NaCrO prepared in step S4 2 Adding strong alkaline anion exchange resin into the solution to remove sulfate radical, adding 244kg hydrogen peroxide with mass concentration of 30%, degrading residual organic matters in the solution and making CrO 2 - Fully oxidized to CrO 4 2- Then will contain CrO 4 2- And heating and evaporating the solution, filtering after crystallization occurs, crystallizing and separating out residual sodium sulfate, then performing secondary evaporation on the filtrate obtained by filtering, and repeating the filtering step for 3 times to obtain sodium chromate crystals.
Performance test:
1. in the treatment of the above examples 1 to 3 and comparative example 1, the following tests were conducted on the content of chromium in the sulfuric acid-containing waste etching solution and the chromium mud in step S2, and the test results are shown in table 1.
TABLE 1
| Technical index | Sulfuric acid concentration (wt%) | Chromium content (wt%) | Etching solution addition amount (kg) |
| Example 1 | 7 | 5 | 536 |
| Example 2 | 12 | 8 | 600 |
| Example 3 | 8.2 | 10 | 982 |
| Comparative example 1 | 5.1 | 8 | 1412 |
It can be seen from the combination of examples 1 to 3 and comparative example and the combination of table 1 that the ammonium persulfate etching solution has a lower sulfuric acid concentration than chromic acid-sulfuric acid, hydrogen peroxide-sulfuric acid etching solutions. In the case where the chromium mud chromium content and the sulfuric acid addition mass ratio were the same, the amount of the etching solution required was too much, which was 2.4 times that of example 2.
2. In the above-described treatment procedures of examples 1 to 3 and comparative example, the filter residue obtained in step S3 was subjected to dehydration treatment, and the filter residue after detection of the dehydration treatment was subjected to the following test, and the test results are shown in table 2.
TABLE 2
| Technical index | Attached water content (wt%) | Calcium sulfate content (wt%) | Chromium content (wt%) |
| Example 1 | 13 | 79 | 0.15 |
| Example 2 | 10 | 83 | 0.07 |
| Example 3 | 14.1 | 76 | 0.13 |
| Comparative example 1 | 12.7 | 68.4 | 1.82 |
| Detection standard | GB/T 5484 | GB/T 21371-2019 | GB/T 30905-2014 |
As can be seen from the combination of examples 1 to 3 and comparative example 1 and the combination of table 2, the sulfuric acid concentration in example 2 is higher than that in comparative example when the acid dissolution temperature is the same, and the lower the chromium content in example 2, the higher the leaching rate of chromium, and thus the higher the sulfuric acid concentration, the higher the leaching rate for chromium.
The concentration of sulfuric acid in the etching solution and the temperature influence the leaching rate of chromium and the content of calcium sulfate in filter residues. Within the specified temperature, the temperature rise favors leaching of chromium. The higher the concentration of sulfuric acid, the higher the leaching rate of chromium and the content of calcium sulfate in the filter residue. The leaching rate of chromium can reach 97.0% -99.1%, and the residual chromium content of filter residues is between 0.07% -0.15% and accords with the limit value of controlled substance chromium less than or equal to 0.5% in the cement plant protocol standard; the content of calcium sulfate is 76-83%, meets the standard of industrial byproduct gypsum for cement (GB/T21371-2019), can be used as a byproduct for cement production in cement factories, realizes the recycling of industrial wastes, and reduces landfill amount and treatment cost
3. The sodium chromate-containing crystals provided in examples 1 to 3 and comparative example 1 above were subjected to the following test, and the test results are shown in table 3.
TABLE 3 Table 3
| Technical index | Sulfate content (wt%) | Sodium chromate content (wt%) |
| Example 1 | 0.29 | 98.5 |
| Example 2 | 0.21 | 99.0 |
| Example 3 | 0.37 | 98.1 |
| Comparative example 1 | 1.64 | 95.7 |
| Detection standard | GB/T214-2007 | HG/T 4312-2012 |
As can be seen from Table 3, the sulfate content in the obtained sodium chromate product is between 0.2% and 0.4%, and the sodium chromate content is more than 98% and meets the standard of HG/T4312-2012 of industrial sodium chromate, so that the sodium chromate product can be used as a raw material for preparing chrome yellow.
As can be seen from the combination of examples 1, 2, 3 and comparative example 1 and the combination of table 3, the ammonium sulfate in the ammonium persulfate etching solution increases the sulfate content in the sodium chromate product and decreases the sodium chromate yield.
It can be seen from the combination of examples 2 and 3 and the combination of Table 3 that the addition amount of hydrogen peroxide has a lower influence on the sodium chromate yield, and that the higher the hydrogen peroxide addition ratio is, the higher the sodium chromate yield is in the prescribed range.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (6)
1. A pretreatment method for co-treatment of sulfuric acid system waste etching liquid and water treatment chromium-containing sludge is characterized by comprising the following steps:
s1: uniformly mixing chromium-containing sludge and water to obtain sludge;
s2: carrying out acid dissolution on the sludge slurry prepared in the step S1 by using sulfuric acid-containing waste etching solution, wherein the acid dissolution temperature is 55-65 ℃, and the mixed solution is obtained after acid dissolution treatment for 2-4 hours, wherein the mass ratio of chromium in the sludge slurry to sulfuric acid in the sulfuric acid-containing waste etching solution is 1 (7.5-9); the sulfuric acid-containing waste etching liquid is selected from chromic acid-sulfuric acid system waste etching liquid or hydrogen peroxide-sulfuric acid system waste etching liquid; the mass fraction of sulfuric acid in the sulfuric acid-containing waste etching liquid is 7% -12%;
s3: filtering the mixed solution prepared in the step S2 to obtain a chromium-containing filtrate and filter residues, wherein the filter residues can be comprehensively utilized as a substitute raw material by a cement kiln after being dehydrated, and in the step S3, the filter residues contain more than or equal to 75wt% of calcium sulfate;
s4: adding a neutralizing agent into the chromium-containing filtrate obtained in the step S3, adjusting the pH value to 14, and then filtering to obtain a chromium-containing filtrate containing CrO 2 - The solution and the copper-rich slag, wherein the copper-rich slag can be used for recovering metallic copper through smelting;
s5: to step S4, crO is added 2 - Adding strong alkaline anion exchange resin into the solution to remove sulfate radical, adding 30% hydrogen peroxide by mass percent, and adding CrO 2 - Oxidation to CrO 4 2- Then evaporating and crystallizing to obtain sodium chromate crystal which can be used as raw material for preparing chrome yellow, the hydrogen peroxide and CrO-containing material 2 - The mass ratio of chromium in the solution was (2).5-3): 1, the sodium chromate crystal contains 0.2 to 0.4 percent of sulfate by mass percent.
2. The pretreatment method for the co-treatment of a sulfuric acid system waste etching solution and a water treatment chromium-containing sludge according to claim 1, wherein the sulfuric acid system waste etching solution has a total chromium content of 0.1-60g/L and a density of 1.1-1.3g/cm 3 The pH is less than 1.
3. The pretreatment method for co-treatment of sulfuric acid system waste etching liquid and water treatment chromium-containing sludge according to claim 1, wherein the chromic acid-sulfuric acid system waste etching liquid contains 1wt% to 3wt% chromic acid and 7wt% to 10wt% sulfuric acid.
4. The pretreatment method for co-treatment of sulfuric acid system waste etching liquid and water treatment chromium-containing sludge according to claim 1, wherein the mass fraction of chromium in the chromium-containing sludge is 5-13%.
5. The pretreatment method for co-treatment of sulfuric acid system waste etching liquid and water-treated chromium-containing sludge according to claim 1, wherein in step S4, the temperature is controlled to 5-10 ℃ during the adjustment of pH to 14.
6. The pretreatment method for co-treatment of sulfuric acid system waste etching liquid and water treatment chromium-containing sludge according to claim 1, wherein the operation of evaporative crystallization is as follows: will contain CrO 4 2- And heating and evaporating the solution, filtering after crystallization occurs, crystallizing and separating out residual sodium sulfate, then performing secondary evaporation on the filtrate obtained by filtering, and repeating the filtering steps to obtain sodium chromate crystals with the mass fraction of 84.0% -85.6% of sodium chromate.
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