CN115197101A - Method for preparing urea by recycling vanadium precipitation wastewater - Google Patents
Method for preparing urea by recycling vanadium precipitation wastewater Download PDFInfo
- Publication number
- CN115197101A CN115197101A CN202210634971.6A CN202210634971A CN115197101A CN 115197101 A CN115197101 A CN 115197101A CN 202210634971 A CN202210634971 A CN 202210634971A CN 115197101 A CN115197101 A CN 115197101A
- Authority
- CN
- China
- Prior art keywords
- vanadium precipitation
- precipitation wastewater
- urea
- recycling
- vanadium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C273/02—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds
- C07C273/04—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of urea, its salts, complexes or addition compounds from carbon dioxide and ammonia
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B17/00—Sulfur; Compounds thereof
- C01B17/22—Alkali metal sulfides or polysulfides
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Abstract
The invention relates to a method for preparing urea by recycling vanadium precipitation wastewater, belonging to the technical field of recycling vanadium precipitation wastewater. The method for preparing urea by recycling vanadium precipitation wastewater comprises the following steps: A. reducing the vanadium precipitation wastewater by a sodium roasting method; B.SO 2 Absorption of (2); C. and (3) preparing urea. The method for preparing urea by recycling vanadium precipitation wastewater has high recycling efficiency and saves cost. The invention treats the vanadium precipitation wastewater to ensure that the yield of the subsequent sodium sulfide can reach 89.3-97.2%, and the subsequent sodium sulfide is easy to leach and purify, and the purity of the concentrated and dried sodium sulfide can reach 97.6-99.9% after simple alkali liquor leaching.
Description
Technical Field
The invention relates to a method for preparing urea by recycling vanadium precipitation wastewater, belonging to the technical field of recycling vanadium precipitation wastewater.
Background
Vanadium has many excellent physical and chemical properties, and is widely used and called as metal vitamin. The application range of vanadium covers a plurality of fields of aerospace, chemistry, batteries, pigments, glass, optics, medicine and the like, wherein the consumption of vanadium in the steel industry accounts for 85 percent of the total production amount of vanadium. The demand of the steel industry directly influences the market quotation of vanadium. About 10% of vanadium is used to produce titanium alloys required by the aerospace industry. Vanadium can be used as a stabilizer and a reinforcer in the titanium alloy, so that the titanium alloy has good ductility and plasticity. In addition, vanadium is used primarily as a catalyst and colorant in the chemical industry. Vanadium has also been used to produce rechargeable hydrogen or vanadium redox batteries. In addition, the new national steel standard regulations require that the vanadium content standard in steel is improved by 25 times. The demand of vanadium is increased sharply due to various reasons, so that the vanadium extraction enterprises produce full production, and a large amount of solid waste generated by vanadium extraction is accumulated, and if the solid waste is not treated in time, the vanadium extraction enterprises can not only face the crisis of production halt; the accumulation of the vanadium extraction tailings can cause serious pollution to the environment.
The treatment of the vanadium extraction tailings in the prior art is to carry out sodium roasting method on the vanadium extraction tailings to extract V 2 O 5 And residual vanadium precipitation wastewater is accumulated, wherein the residual vanadium precipitation wastewater contains ammonium chloride, ammonium sulfate and other impurities. If the soil is not properly treated, not only is the resource waste caused, but also the requirement of clean production is not met, and the soil can be hardened after long-term storage, thereby obviously influencing the surrounding environment.
Disclosure of Invention
The first purpose of the invention is to provide a new method for preparing urea by recycling vanadium precipitation wastewater.
In order to achieve the aim of the invention, the method for preparing urea by recycling the vanadium precipitation wastewater comprises the following steps:
A. reduction of vanadium-precipitating waste water by sodium roasting method, namely extracting V from vanadium slag after vanadium extraction by sodium roasting method 2 O 5 Will extract V 2 O 5 The vanadium precipitation waste water is subjected to gradient roasting, then a reducing agent is added, and the reaction is carried out for 1.5 to 2 hours at the temperature of 1000 to 1150 ℃, SO that solid containing sodium sulfide and SO are obtained 2 、NH 3 、CO 2 A gas; the water content in the vanadium precipitation wastewater is less than 9.5 wt%;
the gradient roasting is firstly heated for 0.25 to 0.3 hour at the temperature of 1000 to 1075 ℃, then heated for 0.5 to 0.6 hour at the temperature of 1085 to 1135 ℃ and finally heated for 0.75 to 0.8 hour at the temperature of 1145 to 1150 ℃;
B.SO 2 absorption of (2): the SO in the step A is treated 2 After absorption, the CO is removed 2 And NH 3 Separating;
C. preparation of urea: separating CO 2 And NH 3 Reacting to obtain the urea.
The gradient roast is first at 1000-1075 deg.c, which refers to the ambient temperature range provided by the rotary kiln, not the temperature range of water.
CO 2 And NH 3 The separation method may be a conventional separation method.
For example, passing a gas over dilute H 2 SO 4 First, NH 3 Absorb and convert CO 2 Separating, adding NaOH into the solution after absorbing ammonia gas, and collecting NH 3。 Further, for example, the existing methods such as dilution and differential pressure can be used to separate CO 2 And NH 3 For example, CN102688651a discloses a method for separating mixed gas of ammonia and carbon dioxide. As long as it can remove CO 2 And NH 3 Separation is only needed.
Separating CO 2 And NH 3 The urea production method by reaction is a conventional urea production process by carbon dioxide stripping, and CO can be firstly used 2 After purification and compression, NH 3 Cooling, condensing and then carrying out a carbon dioxide stripping method to produce urea.
In a specific embodiment, the reducing agent is at least one of pulverized coal and fly ash.
In a specific embodiment, the mass of the vanadium precipitation wastewater after gradient roasting in the step A is X, and the mass ratio of X to the reducing agent is 4-5:1.
In a specific embodiment, the step A of gradient roasting is carried out until the moisture in the vanadium precipitation wastewater is completely evaporated.
In one embodiment, the particle size of the reducing agent should be kept below 7 mesh.
In a specific embodiment, the method further comprises leaching the solid containing sodium sulfide with 80% caustic soda solution at 80-85 ℃ for 4-4.5 h, taking the supernatant, concentrating and drying to obtain sodium sulfide.
In one embodiment, the sodium sulfide is present in a yield of 89.3 to 97.2% and a purity of 97.6 to 99.9%.
In one embodiment, SO in step B 2 With saturated NaHCO 3 。
In one embodiment, the reaction of step C is the reaction of CO 2 Compressing to 14-15 Mpa to obtain NH 3 Condensing to liquid ammonia, raising pressure of the liquid ammonia by 16.0-17.5 Mpa, and then carrying out carbon dioxide stripping to produce urea.
In one embodiment, the temperature of the reaction in step C is 180 to 185 ℃.
Has the beneficial effects that:
the method for preparing urea by recycling vanadium precipitation wastewater has high recycling efficiency and saves cost. The invention treats the vanadium precipitation wastewater to ensure that the yield of the subsequent sodium sulfide can reach 89.3-97.2%, and the subsequent sodium sulfide is easy to leach and purify, and the purity of the concentrated and dried sodium sulfide can reach 97.6-99.9% after simple alkali liquor leaching.
Drawings
FIG. 1 is a diagram of a process for practicing the present invention.
Detailed Description
In order to achieve the aim of the invention, the method for preparing urea by recycling the vanadium precipitation wastewater comprises the following steps:
A. sodium salt roastingReduction of vanadium-precipitation waste water, namely extracting V from vanadium slag after vanadium extraction by a sodium salt roasting method 2 O 5 Will extract V 2 O 5 The vanadium precipitation waste water is subjected to gradient roasting, then a reducing agent is added, and the reaction is carried out for 1.5 to 2 hours at the temperature of 1000 to 1150 ℃, SO that solid containing sodium sulfide and SO are obtained 2 、NH 3 、CO 2 A gas; the water content in the vanadium precipitation wastewater is less than 9.5 wt%;
the gradient roasting is firstly heated for 0.25 to 0.3 hour at the temperature of 1000 to 1075 ℃, secondly heated for 0.5 to 0.6 hour at the temperature of 1085 to 1135 ℃ and finally heated for 0.75 to 0.8 hour at the temperature of 1145 to 1150 ℃;
B.SO 2 absorption of (2): the SO in the step A is treated 2 After absorption, the CO is removed 2 And NH 3 Separating;
C. preparation of urea: separating CO 2 And NH 3 Reacting to obtain the urea.
The gradient roast is first at 1000-1075 deg.c, which refers to the ambient temperature range provided by the rotary kiln, not the temperature range of water.
Separating CO 2 And NH 3 The method for producing urea by reaction can be a conventional process for producing urea by carbon dioxide stripping, and CO can be firstly used 2 After purification and compression, NH 3 Cooling, condensing and then carrying out a carbon dioxide stripping method to produce urea.
In a specific embodiment, the reducing agent is at least one of pulverized coal and fly ash.
In a specific embodiment, the mass of the vanadium precipitation wastewater after the gradient roasting in the step A is X, and the ratio of the mass of X to the mass of the reducing agent is 4-5:1.
In a specific embodiment, the gradient roasting in the step A is carried out until the moisture in the vanadium precipitation wastewater is completely evaporated.
In one embodiment, the particle size of the reducing agent should be kept below 7 mesh.
In a specific embodiment, the method further comprises leaching the solid containing sodium sulfide with 80% caustic soda solution at the temperature of 80-85 ℃ for 4-4.5 h, taking the supernatant, concentrating and drying to obtain sodium sulfide.
In one embodiment, the sodium sulfide is present in a yield of 89.3 to 97.2% and a purity of 97.6 to 99.9%.
In one embodiment, SO in step B 2 With saturated NaHCO 3 。
In one embodiment, the reaction of step C is the reaction of CO 2 Compressing to 14-15 Mpa to obtain NH 3 Condensing to liquid ammonia, raising pressure of liquid ammonia by 16.0-17.5 Mpa, and then carrying out carbon dioxide stripping to produce urea.
In one embodiment, the temperature of the reaction in step C is 180 to 185 ℃.
The following examples are provided to further illustrate the embodiments of the present invention and are not intended to limit the scope of the present invention.
Example 1
The water content in the vanadium precipitation wastewater is 9.1 percent, the vanadium precipitation wastewater is conveyed to a reaction workshop for roasting, and is subjected to step-gradient continuous roasting through a rotary chamber, and the roasting is carried out for 0.28h at 1054 ℃, 0.55h at 1100 ℃ and 0.77h at 1148 ℃ in sequence. After roasting, the water is completely evaporated. The model number of the rotary furnace KY-LQ is 600-10m, and then the rotary furnace KY-LQ is mixed with high-quality coal powder (the particle size of the coal powder is less than 7 meshes) with high carbon content, and the weight ratio of the solid mass after the wastewater is dried to the coal powder is 5:1. Reacting for 1.8h at 1020 ℃ by taking coal gas as a heat source. The model of the reaction rotary furnace is QC-M1800-18IK. The equipment processing capacity is 5 t/h.
After the reaction of the rotary furnace, the reduced gas is directly led to the absorption chamber and saturated NaHCO is used 3 Absorb away SO 2 Remaining NH 3 And CO 2 Gas is introduced into dilute H 2 SO 4 First, NH 3 Absorb and convert CO 2 Separating, adding NaOH into the solution absorbing ammonia gas, collecting NH 3 ，CO 2 The pressure was raised to about 14.4MPa, and the product was fed into the stripper from the bottom. NH (NH) 3 Firstly compressing the liquid ammonia into liquid ammonia, boosting the pressure of the liquid ammonia to 16.8Mpa8, preheating and filtering the liquid ammonia, then introducing the liquid ammonia into a urea synthetic tower, finally evaporating and granulating the generated product,obtaining finished product urea.
Cooling the residual solid after the reaction in the rotary furnace to 700 ℃, putting the solid into NaOH solution with the temperature of 80 ℃ and the concentration of 80 percent for leaching for 4.5 hours, taking supernatant after leaching, concentrating and drying to obtain the sodium sulfide.
The yield of the obtained sodium sulfide is 96.8 percent; the purity of the sodium sulfide is detected to be 99.2%.
Example 2
a. 1kg of vanadium precipitation wastewater is continuously roasted by adopting a step gradient, wherein the mass fraction of Na in the vanadium precipitation wastewater is calculated 2 SO 4 68.0％，(NH 4 ) 2 SO 4 20.2％，H 2 O 9.1％，NH 4 0.8 percent of Cl0.9 percent and the rest 1.9 percent. The process of the sectional gradient continuous roasting comprises the following steps: firstly, heating for 0.25h at 1054 ℃; heating at 1100 deg.C for 0.5h; finally heating at 1148 deg.C for 0.75h. After the step gradient continuous roasting and sintering, completely evaporating the water in the vanadium precipitation wastewater;
b. pulverizing coal powder until the particle size is less than 7 meshes;
c. mixing the raw materials subjected to the sectional gradient continuous roasting with coal powder according to the weight ratio of 5:1, heating by using coal gas for reduction reaction at the reaction temperature of 1000 ℃ for 2 hours to obtain a solid pre-product and mixed gas;
d. cooling the pre-product to 700 ℃, putting the pre-product into 80 ℃ NaOH solution with the concentration of 80 percent, leaching for 4.5 hours, taking supernatant fluid after leaching, concentrating and drying to obtain the sodium sulfide.
The weight of the obtained sodium sulfide is 356.1g, and the yield is 95.4%; the purity of the sodium sulfide is detected to be 99.5%.
NH 3 And CO 2 Separation of CO 2 After purification and compression, NH 3 The liquid ammonia is compressed, preheated and filtered, then the liquid ammonia is introduced into a urea synthesis tower, and finally the produced product is evaporated and granulated to obtain 112g of finished product urea.
Comparative example 1
a. Taking 1kg of vanadium precipitation wastewater, wherein Na is contained in the wastewater 2 SO 4 68.0％，(NH 4 ) 2 SO 4 20.2％，H 2 O9.0%, willAfter the vanadium precipitation wastewater is heated for 6 hours at 1150 ℃, the water content of the vanadium precipitation wastewater is 0 percent.
b. Pulverizing coal powder until the particle size is less than 7 meshes;
c. mixing the dried raw material and coal powder according to a weight ratio of 5:1, heating by using coal gas to perform reduction reaction, wherein the reaction temperature is 1000 ℃, and the reaction time is controlled to be 2 hours, so as to obtain a pre-product;
d. cooling the pre-product to 700 ℃, putting the pre-product into 80 ℃ NaOH solution with the concentration of 80 percent, leaching for 4.5 hours, taking supernatant fluid after leaching, concentrating and drying to obtain the sodium sulfide.
The weight of sodium sulfide obtained was 194.8g, the yield was 60.2%, and the purity was determined to be 90.4%.
NH 3 And CO 2 Separation of CO 2 After purification and compression, NH 3 The liquid ammonia is compressed, preheated and filtered, then the liquid ammonia is introduced into a urea synthesis tower, and finally the produced product is evaporated and granulated to obtain 72g of finished product urea.
Claims (10)
1. The method for preparing urea by recycling vanadium precipitation wastewater is characterized by comprising the following steps:
A. reduction of vanadium-precipitating waste water by sodium roasting method, namely extracting V from vanadium slag after vanadium extraction by sodium roasting method 2 O 5 Will extract V 2 O 5 The vanadium precipitation waste water is subjected to gradient roasting, then a reducing agent is added, and the reaction is carried out for 1.5 to 2 hours at the temperature of 1000 to 1150 ℃, SO that solid containing sodium sulfide and SO are obtained 2 、NH 3 、CO 2 A gas; the water content in the vanadium precipitation wastewater is less than 9.5 wt%;
the gradient roasting is firstly heated for 0.25 to 0.3 hour at the temperature of 1000 to 1075 ℃, then heated for 0.5 to 0.6 hour at the temperature of 1085 to 1135 ℃ and finally heated for 0.75 to 0.8 hour at the temperature of 1145 to 1150 ℃;
B.SO 2 absorption of (2): the SO in the step A is treated 2 After absorption, the CO is removed 2 And NH 3 Separating;
C. preparation of urea: separating CO 2 And NH 3 Reacting to obtain the urea.
2. The method for preparing urea by recycling vanadium precipitation wastewater according to claim 1, wherein the reducing agent is at least one of pulverized coal and fly ash.
3. The method for preparing urea by recycling vanadium precipitation wastewater according to claim 1, wherein the mass of the vanadium precipitation wastewater left after the gradient roasting in step A is X, and the mass ratio of X to the reducing agent is 4-5:1.
4. The method for preparing urea by recycling vanadium precipitation wastewater according to claim 1 or 2, wherein the step A comprises the step of gradient roasting until the moisture in the vanadium precipitation wastewater is completely evaporated.
5. The method for preparing urea by recycling vanadium precipitation wastewater according to claim 1 or 2, wherein the particle size of the reducing agent is kept below 7 meshes.
6. The method for preparing urea by recycling vanadium precipitation wastewater according to claim 1 or 2, characterized by further comprising leaching sodium sulfide-containing solids with 80% caustic soda solution at a temperature of 80-85 ℃ for 4-4.5 h, taking supernatant, concentrating and drying to obtain sodium sulfide.
7. The method for preparing urea by recycling vanadium precipitation wastewater according to claim 6, wherein the yield of the sodium sulfide is 89.3-97.2%, and the purity of the sodium sulfide is 97.6-99.9%.
8. The method for preparing urea by recycling vanadium precipitation wastewater according to claim 1 or 2, wherein SO in the step B is SO 2 With saturated NaHCO 3 。
9. The method for preparing urea by recycling vanadium precipitation wastewater according to claim 1 or 2, wherein the step C isThe reaction is to react CO 2 Compressing to 14-15 Mpa, NH 3 Condensing to liquid ammonia, raising pressure of the liquid ammonia by 16.0-17.5 Mpa, and then carrying out carbon dioxide stripping to produce urea.
10. The method for preparing urea by recycling vanadium precipitation wastewater according to claim 1 or 2, wherein the reaction temperature in the step C is 180-185 ℃.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210634971.6A CN115197101A (en) | 2022-06-07 | 2022-06-07 | Method for preparing urea by recycling vanadium precipitation wastewater |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210634971.6A CN115197101A (en) | 2022-06-07 | 2022-06-07 | Method for preparing urea by recycling vanadium precipitation wastewater |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115197101A true CN115197101A (en) | 2022-10-18 |
Family
ID=83575948
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210634971.6A Withdrawn CN115197101A (en) | 2022-06-07 | 2022-06-07 | Method for preparing urea by recycling vanadium precipitation wastewater |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115197101A (en) |
-
2022
- 2022-06-07 CN CN202210634971.6A patent/CN115197101A/en not_active Withdrawn
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104876250B (en) | Method for extracting lithium and removing aluminum by treating lepidolite with sulfuric acid | |
| CN102031381B (en) | Process for preparing sodium pyroantimonate from arsenic- and stibium-containing smoke ash | |
| CN104152687B (en) | Aluminium, vanadium, molybdenum, the production technology of nickel element three-waste free discharge are extracted from black shale | |
| CN102828025B (en) | Method for extracting V2O5 from stone coal navajoite | |
| CN103738986B (en) | A kind of dolomite calcination water-soluble separating calcium and magnesium produce the method for magnesium hydroxide and calcium carbonate | |
| CN109957657B (en) | Method for simultaneously recycling iron, sodium and aluminum from red mud | |
| CN112280976B (en) | Method for recycling valuable metals from laterite-nickel ore and regenerating and recycling acid | |
| CN102628106A (en) | Technology for recycling manganese and lead from electrolytic manganese anode slag | |
| CN113651342A (en) | Method for producing lithium product by processing lepidolite through nitric acid atmospheric pressure method | |
| CN105671323A (en) | Method for comprehensively recycling copper and rhenium from rhenium-rich residues | |
| CN113772696A (en) | Method for producing various lithium products by processing lepidolite through nitric acid pressurization method | |
| CN111575478A (en) | Method for separating metal in heavy oil | |
| WO2023010969A1 (en) | Method for recycling spent lithium-ion batteries | |
| CN103937973A (en) | Organic-inorganic combined pyrolusite reduction method | |
| CN103449517A (en) | Method for preparing white arsenic from arsenic-containing dust in evaporation-free manner | |
| CN101148268A (en) | Method for separating and extracting calcium tungstate and tin slag by utilizing tungsten-containing tin furnace residue or tungsten-tin middlings | |
| CN114058848A (en) | System and process for recovering copper, nickel, zinc, chromium and iron from electroplating sludge or other multi-metal mixture | |
| RU2515154C1 (en) | Method of producing vanadium pentoxide from vanadium-containing slag | |
| CN105330344B (en) | A kind of preparation method for extracting potassium sulfate from blast furnace process gas ash | |
| CN105200236B (en) | A kind of method and device that W and V is reclaimed from waste flue gas denitration catalyst | |
| CN102154546A (en) | Method for smelting molybdenum-nickel mineral association by wet process | |
| CN101693554A (en) | Method for extracting vanadium pentoxide from stone coal ores | |
| CN111893327B (en) | Short-process efficient preparation method of tungsten oxide by decomposing scheelite concentrate with mixed acid | |
| CN101705377B (en) | Method for extracting vanadium from stone coal by wet-process enrichment and pyrogenic-process conversion | |
| CN219772165U (en) | Blast furnace cloth bag dust and ash removal processing system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20221018 |
|
| WW01 | Invention patent application withdrawn after publication |