CN110540497A - Method for preparing oxalic acid by using yellow phosphorus tail gas - Google Patents
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- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/02—Preparation of carboxylic acids or their salts, halides or anhydrides from salts of carboxylic acids
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/41—Preparation of salts of carboxylic acids
Abstract
the invention discloses a method for preparing oxalic acid by using yellow phosphorus tail gas, which mainly comprises the following three steps: (1) preparing sodium formate; (2) preparing sodium oxalate; (3) and (4) preparing oxalic acid. The invention relates to a method for preparing oxalic acid by taking yellow phosphorus tail gas as a raw material and combining the methods of sodium formate, self-heating fluidized dehydrogenation, calcium barium ion exchange and the like, thereby achieving the purposes of energy utilization and heavy metal pollution elimination, and belonging to the fields of energy conservation, emission reduction and environmental protection. The technology opens up a new path for the resource utilization of the yellow phosphorus tail gas, the industrial waste gas is used for replacing the emission reduction effect generated by fossil fuel, the technology only needs to increase proper investment, the fossil fuel is not needed, and the energy-saving and emission-reduction effects are very obvious.
Description
Technical Field
the invention relates to the technical field of energy conservation and emission reduction and environmental protection, in particular to a method for preparing oxalic acid by taking yellow phosphorus tail gas as a raw material and combining the methods of sodium formate, self-heating fluidized dehydrogenation, calcium barium ion exchange and the like.
Background
Oxalic acid is an important organic industrial raw material. Oxalic acid can be used for chemical synthesis, such as the preparation of basic chemical products such as oxamide, oxalate and the like; oxalic acid can be used in the pharmaceutical industry and is commonly used in medicine for preparing antibiotics, borneol and other medicines; oxalic acid and its derivatives are intermediates in the manufacture of many pharmaceutical products, such as cromolyn sodium and isoxazole hydrazine.
oxalic acid and its salts and esters are widely used in metal cleaning, metal surface treatment, textile printing and dyeing, leather processing, rare earth element extraction, medicine production and polymer and catalyst preparation.
the oxalic acid can be used for extracting, separating and refining rare earth elements, a saturated oxalic acid solution is added into the rare earth solution to generate oxalate RE2(C2O4)2, and the oxalate is calcined under normal pressure to obtain rare earth oxide.
oxalic acid can be used in the textile and printing and dyeing processing industries, can be used as a bleaching agent for cleaning textiles, can be used as a reducing agent for dyeing wool fabrics, and is also a raw material of a dye intermediate; in the leather industry, oxalic acid is used as a tanning agent, a decolorant and the like; oxalic acid can also be used for the synthesis of polymers, the refining of esters in the grease industry, and the like.
The largest users of oxalic acid will be in the chemical industry, and a large amount of oxalic acid is used for producing dimethyl oxalate and then used for producing ethylene glycol through hydrogenation.
The market demand for oxalic acid is large and most is for export.
The current production method of oxalic acid mainly utilizes petroleum processing products such as alkene, alkyne, alcohol and aldehyde oxidation method, and the yield is very low due to the limitation of raw material supply, price and other factors. The production method for oxalic acid by using sodium formate has the disadvantages of serious pollution, high production cost, no large-scale production and low yield.
The yellow phosphorus tail gas is rich in carbon monoxide, contains CO 80-90% (vol.), H25-7% and a heat value 10750-12000 kJ/Nm3, and belongs to medium-heat value coal gas. The yellow phosphorus tail gas can be used as fuel gas and synthesis gas, and can be used as a carbon chemical raw material gas by utilizing the rich carbon monoxide in the yellow phosphorus tail gas, and can be used for synthesizing various chemical products according to the requirements, such as carbon chemical products for synthesizing sodium formate, methanol, dimethyl ether, methyl formate, dimethyl carbonate and the like, and can also be used as a raw material gas for synthesizing ammonia.
The carbon monoxide in the yellow phosphorus tail gas can be converted into oxalic acid by a gas phase coupling method, so that the method has wide prospect, and is difficult to realize industrialization in a short time due to high requirements on a synthesis process and complex process in research.
Disclosure of Invention
In order to overcome the defects, the inventor of the invention continuously reforms and innovates through long-term exploration and trial and multiple experiments and efforts, and provides a method for preparing oxalic acid by using yellow phosphorus tail gas.
In order to achieve the purpose, the invention adopts the technical scheme that: a method for preparing oxalic acid by using yellow phosphorus tail gas comprises the following operations:
s1, removing CO2 in the yellow phosphorus tail gas: dedusting, desulfurizing, dephosphorizing and purifying the yellow phosphorus tail gas, pressurizing to 1.8-2.0MPa, and removing CO2 in the yellow phosphorus tail gas to below 50mg/Nm 3;
S2, preparing sodium formate: adding the decarburized yellow phosphorus tail gas and a NaOH solution into a synthesis reaction tower, and reacting at 150-200 ℃ and 1.8MPa to generate sodium formate with the concentration of 36-37%; evaporating the sodium formate solution in vacuum, concentrating the content of sodium formate in the sodium formate solution to 75% on average, cooling and crystallizing, and separating to obtain solid sodium formate with the water content of 5%;
S3, preparing sodium oxalate: sending the solid sodium formate obtained in the S2 into a dehydrogenation tower, heating by using circulating nitrogen at 400-420 ℃ for decomposition and dehydrogenation, enabling the temperature of the circulating nitrogen containing hydrogen and powdered sodium oxalate to be about 300 ℃, enabling the circulating nitrogen and the powdered sodium oxalate to enter a heat exchanger for heat exchange with low-temperature circulating nitrogen and rise to more than 150 ℃, enabling the circulating nitrogen and the powdered sodium oxalate to enter a catalytic combustor, adding air for combustion, rising the temperature to 400-420 ℃ for returning use, washing the circulating nitrogen containing hydrogen and the powdered oxalic acid by using water after heat exchange, and cooling at the same time to prepare suspension with the sodium oxalate content of 400 kg/m 3;
S4, preparation of calcium oxalate: lime is used as a precipitator to convert sodium oxalate into calcium oxalate precipitate;
S5, acidifying by calcium oxalate: calcium oxalate enters an acidification tank, sulfuric acid is added for acidification reaction to generate gypsum and crude oxalic acid, a filter is used for filtering, filter residues are gypsum and are discharged, and filtrate is crude oxalic acid;
S6, removing sulfate radicals in the crude oxalic acid: feeding the crude oxalic acid into a barium tank, adding a barium hydroxide suspension, generating a barium sulfate precipitate with excessive sulfate radicals, and filtering the precipitate;
S7, removing cations in oxalic acid: and (3) carrying out ion exchange by adopting a strong acid cation resin to remove cations in the crude oxalic acid solution. Obtaining purified oxalic acid solution;
S8, preparing oxalic acid: the refined oxalic acid is subjected to vacuum multi-effect evaporation, so that the temperature of the oxalic acid solution is reduced, and the oxalic acid is prevented from being decomposed; oxalic acid is concentrated to 55 percent, the solution is cooled to 20 ℃, crystallized and separated, and the oxalic acid product is obtained after drying and dehydration.
according to the method for preparing oxalic acid by using the yellow phosphorus tail gas, the further preferable technical scheme is as follows: pressurizing to 2MPa when removing CO2 in S1, washing with water, removing CO2 to be below 0.5%, then washing with 2-3% dilute alkali liquor, and removing CO2 in the purified yellow phosphorus tail gas to be below 50mg/Nm 3.
according to the method for preparing oxalic acid by using the yellow phosphorus tail gas, the further preferable technical scheme is as follows: s4, specifically, putting the sodium oxalate suspension in a calcification tank, adding lime slurry into the calcification tank according to the concentration of 14% in proportion, wherein the proportion of the sodium oxalate to the lime is (COONa): CaO = 1: 1.15; the reaction time is 2 h; the concentration of the alkali liquor is 80-100 g/L.
According to the method for preparing oxalic acid by using the yellow phosphorus tail gas, the further preferable technical scheme is as follows: and (3) in S5, feeding calcium oxalate into an acidification tank, wherein the feeding ratio is H2SO 4: CaC2O4=1.25 (molar ratio), adding sulfuric acid with initial concentration of 28-30%; the reaction time is 1 h.
According to the method for preparing oxalic acid by using the yellow phosphorus tail gas, the further preferable technical scheme is as follows: s6, removing sulfate radical from coarse oxalic acid, which is to prepare barium hydroxide with 10-15% concentration with hot condensed water, add it into coarse oxalic acid solution while stirring to generate barium sulfate precipitate until no sulfate radical is detected with barium chloride solution.
According to the method for preparing oxalic acid by using the yellow phosphorus tail gas, the further preferable technical scheme is as follows: the specific operation in S7 is dynamically carried out in a fixed bed ion exchange column, the ion exchange resin is immobile, the solution flows through the ion exchange resin under the flowing condition for ion exchange, and cations are trapped in the resin to obtain purified oxalic acid, wherein the cations in S7 are mainly Ca2+, Al3+, Fe3+, As3+, Hg2+ and Pb 2.
Compared with the prior art, the invention has the following advantages:
1. the invention opens up a new path for the resource utilization of the yellow phosphorus tail gas by reusing the yellow phosphorus tail gas, and the industrial waste gas is used for replacing the emission reduction effect generated by fossil fuel, the technology only needs to increase proper investment, the fossil fuel is not needed, the energy-saving and emission-reduction effects are very obvious, 3.3 tons of standard coal can be saved when 1 ton of oxalic acid is produced, and the emission reduction TCO2 of CO2 is =5.3 tons.
2. The invention only needs lower cost as waste gas treatment, and has high value-added product output, the economic benefit is obvious, the operation cost of each 1 ton of oxalic acid is not more than 2500 yuan, and the output value reaches more than 4000 yuan.
3. The invention fully utilizes the released heat, avoids using harmful substances as raw materials, does not produce secondary pollution, realizes environmental protection and is a blue sky project for benefiting human beings.
drawings
in order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a process flow diagram of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are a part of the embodiments of the present invention, not all of the embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. Thus, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention.
it should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it may not be further defined and explained in subsequent figures.
As shown in fig. 1: the invention takes yellow phosphorus tail gas as a raw material, prepares oxalic acid by combining methods of sodium formate, self-heating fluidized dehydrogenation, calcium barium ion exchange and the like, achieves the purposes of energy utilization and heavy metal pollution elimination, and belongs to the fields of energy conservation, emission reduction and environmental protection.
the principle of the environment-friendly and energy-saving preparation of oxalic acid from yellow phosphorus tail gas is as follows:
1. Purifying yellow phosphorus tail gas by dedusting, desulfurizing, dephosphorizing and the like, pressurizing to 2MPa, washing with water to remove CO2 to be below 0.5%, washing with 2-3% dilute alkali liquor, removing CO2 in the refined yellow phosphorus tail gas to be below 50mg/Nm3, heating the yellow phosphorus tail gas and a sodium hydroxide solution to 160-200 ℃, and reacting CO in the yellow phosphorus tail gas and a NaOH solution in a sodium formate reactor to generate sodium formate, wherein the main reaction equation is as follows:
CO+NaOH==HCOONa （1）
2. sodium oxalate is prepared by decomposing sodium formate
Sodium formate is heated to 400 ℃ to decompose and dehydrogenate to generate sodium oxalate, and the reaction is as follows:
(2)
The hydrogen generated by decomposing the sodium formate is combusted at low temperature by utilizing the catalyst to generate heat for heating the circulating inert gas for decomposing the sodium formate, and an external heat source is not needed.
3. Preparation of crude oxalic acid by calcium barium precipitation method
Lime is used as a precipitator to convert sodium oxalate into calcium oxalate precipitate, and the steps are as follows:
Firstly, sodium oxalate is prepared into suspension with a certain concentration in a reaction tank, and then lime milk is added for calcification reaction to generate calcium oxalate sediment and NaOH solution, and the reaction is as follows:
CaO + HO + （COONa） == （COO）Ca ↓ + 2NaOH （3）
And (4) carrying out three-time washover on the calcium oxalate filter cake to reach the standard, and then sending the calcium oxalate filter cake to acidification. The NaOH solution extracted for the first time is evaporated to 25% concentration and returned to the sodium formate working procedure.
Secondly, adjusting the calcium oxalate filter cake to a certain concentration, adding concentrated sulfuric acid for acidification to generate calcium sulfate precipitate, and separating out oxalic acid, wherein the reaction is as follows:
（COO）Ca +HSO == (HCOOH) + CaSO↓ （4）
After filtration, the oxalic acid solution is separated from the calcium sulfate precipitate.
Third step of barium hydroxide precipitation
In the acidification process of calcium oxalate, in order to improve the acidification conversion rate, the sulfuric acid is excessive, SO 42-in the crude oxalic acid adopts barium hydroxide to generate barium salt precipitate, and the reaction is as follows:
Ba（OH） + 2H + SO → BaSO↓ + 2HO
Filtering the barium sulfate to obtain crude oxalic acid.
4. preparation of oxalic acid
The first step is as follows: the purified crude oxalic acid solution of oxalic acid solution contains excessive Ca2+, Mg +2, Fe2+, Al3+ and other ions, and is ion exchanged with strong acid cation resin to eliminate the cations in the crude oxalic acid solution. A purified oxalic acid solution is obtained.
The second step is that: the concentration of the refined oxalic acid solution is about 5 percent, and the oxalic acid is obtained after concentration, cooling and crystallization.
The invention provides a method for preparing oxalic acid by utilizing yellow phosphorus tail gas, which mainly comprises the following three steps:
(1) preparing sodium formate; (2) preparing sodium oxalate; (3) preparing oxalic acid; the method comprises the following specific steps:
(1) preparing sodium formate: the refined yellow phosphorus tail gas enters a compressor through a gas-liquid separator to be compressed to 1.8-2.0MPa, enters a decarbonizing tower to remove CO2, then enters a sodium formate synthesis tower, carbon monoxide and sodium hydroxide react in the synthesis reaction tower to generate a sodium formate solution, the mixture of the sodium formate solution, nitrogen, trace carbon monoxide gas and the like enters a hydrocyclone separator for gas-liquid separation after pressure relief, and the mixed gas is discharged into the atmosphere. The sodium formate solution is taken out for evaporation and concentration, cooling and crystallization, and is separated into solid sodium formate.
(2) Preparing sodium oxalate: sodium formate is sent into a dehydrogenation kiln, heated to 400-420 ℃ by thermal cycle nitrogen for decomposition and dehydrogenation, the temperature of hydrogen-containing cycle nitrogen and powdered sodium oxalate is about 300 ℃, the hydrogen-containing cycle nitrogen and powdered sodium oxalate enter a heat exchanger for heat exchange to rise to more than 150 ℃, the hydrogen-containing cycle nitrogen enters a catalytic combustor, a certain amount of air is added for combustion, the temperature rises to 420 ℃, the hydrogen-containing cycle nitrogen and powdered sodium oxalate return to a dehydrogenation tower for heating, the temperature of the heat-exchanged cycle nitrogen and powdered sodium oxalate is below 140 ℃, the heat-exchanged cycle nitrogen and the powdered sodium oxalate enter a water washing cooling tower to be prepared into slurry for next process, and the powdered sodium oxalate is sent to the catalytic combustor for combustion and heating.
(3) Preparing oxalic acid: feeding the sodium oxalate slurry into a calcification tank, adding a certain amount of lime, carrying out calcification reaction to generate calcium oxalate precipitate and NaOH solution, filtering with a filter to obtain filter residue which is calcium oxalate, wherein the filtrate is NaOH dilute solution, and concentrating alkali liquor to 30% and returning the alkali liquor to a sodium formate synthesis tower for use.
calcium oxalate enters an acidification tank, a certain amount of sulfuric acid is added to carry out acidification reaction to generate gypsum and crude oxalic acid, a filter is used for filtering, filter residues are gypsum and are discharged, and filter liquor is crude oxalic acid.
The coarse oxalic acid enters a barium tank, a certain amount of barium hydroxide suspension is added to generate barium sulfate precipitate with excessive sulfate radical, the precipitate is filtered out and sent to a cation exchange column for ion exchange, and the fine and dilute oxalic acid is obtained after the cations are removed.
And (4) evaporating the refined diluted oxalic acid to 55% by multiple effect under reduced pressure, cooling and crystallizing, and separating and drying to obtain the oxalic acid product.
The following example illustrates the operation of preparing oxalic acid from yellow phosphorus tail gas according to the requirement of oxalic acid quality index "industrial oxalic acid GB/T1626-2008", and is specifically realized by the following steps:
1. CO2 removal from refined yellow phosphorus tail gas: pressurizing the yellow phosphorus tail gas to 1.8-2 MPa, washing with water to reduce CO2 of the yellow phosphorus tail gas to be below 0.5%, and washing with dilute alkali liquor to remove CO2 to be below 50mg/Nm 3.
2. Preparing sodium formate: reacting the decarbonized yellow phosphorus tail gas with 30% NaOH solution at 150-170 ℃ under 1.8MPa to generate sodium formate, wherein the concentration of the sodium formate is about 36-37%; the sodium formate solution is evaporated in vacuum, the content of sodium formate in the sodium formate solution is concentrated to 75 percent on average, and then the sodium formate solution is cooled and crystallized, and solid sodium formate with the water content of 5 percent is obtained by separation.
3. Preparing sodium oxalate: sending solid sodium formate into a dehydrogenation tower, heating by using circulating nitrogen at 400-420 ℃ for decomposition and dehydrogenation, enabling the temperature of the circulating nitrogen containing hydrogen and powdered sodium oxalate to be about 300 ℃, enabling the circulating nitrogen and the powdered sodium oxalate to enter a heat exchanger for heat exchange to rise to more than 150 ℃, enabling the circulating nitrogen and the powdered sodium oxalate to enter a catalytic combustor, adding a certain amount of air for combustion, enabling the temperature to rise to 400-420 ℃ for return use, washing the circulating nitrogen containing hydrogen and the powdered oxalic acid by using water after heat exchange, and cooling at the same time to prepare suspension with the sodium oxalate content of 400 kg/m 3.
4. Preparing calcium oxalate: adding the sodium oxalate suspension into a calcification tank, preparing lime slurry into 14% of the lime slurry according to a proportion, and adding the lime slurry for calcification, wherein the proportion of the sodium oxalate to the lime is (COONa): CaO = 1: 1.15; reaction time is 2 hours; ③ 80-100 g/L of alkali liquor.
5. acidification by calcium oxalate: the calcium oxalate enters an acidification tank, and the feed ratio is (1) H2SO 4: CaC2O4=1.25 (molar ratio), adding (2) sulfuric acid with the initial concentration of 28-30%; (3) the reaction time is 1 h.
6. removing sulfate radicals in the crude oxalic acid: barium hydroxide is prepared to a concentration of 10-15% using hot condensed water, and added to the crude oxalic acid solution with stirring to cause precipitation of barium sulfate until no sulfate radicals are detected with the barium chloride solution.
7. Removing cations such As Ca2+, Al3+, Fe3+, As3+, Hg2+, Pb2+ and the like in the oxalic acid: the ion exchange operation mode is dynamically carried out in a fixed bed ion exchange column, the ion exchange resin is immobile, the solution flows through the ion exchange resin under the flowing condition for ion exchange, cations are trapped in the resin, and the oxalic acid is purified.
8. Preparing oxalic acid: the refined oxalic acid is evaporated in multiple vacuum effects, so that the temperature of the oxalic acid solution is reduced and the oxalic acid is prevented from being decomposed. Oxalic acid is concentrated to 55 percent, the solution is cooled to 20 ℃, crystallized and separated, and the oxalic acid product is obtained after drying and dehydration.
The invention takes yellow phosphorus tail gas as raw material, realizes the optimized combination, has no pollution and low production cost, and prepares oxalic acid by combining the methods of sodium formate, autothermal dehydrogenation, calcium barium ion exchange and the like, thereby achieving the purposes of energy utilization and heavy metal pollution elimination. Proper investment is increased, fossil fuel is not needed, the energy-saving and emission-reducing effects are very obvious, the energy-saving efficiency is more than 20%, the emission-reducing range is large, the emission-reducing efficiency is more than 50%, the waste gas treatment does not need cost, and the waste gas treatment has high value-added product output, has obvious economic benefit and benefits human beings.
the above is only a preferred embodiment of the present invention, and it should be noted that the above preferred embodiment should not be considered as limiting the present invention, and the protection scope of the present invention should be subject to the scope defined by the claims. It will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the spirit and scope of the invention, and these modifications and adaptations should be considered within the scope of the invention.
Claims (7)
1. A method for preparing oxalic acid by using yellow phosphorus tail gas is characterized by comprising the following operations:
s1, removing CO2 in the yellow phosphorus tail gas: dedusting, desulfurizing, dephosphorizing and purifying the yellow phosphorus tail gas, pressurizing to 1.8-2.0MPa, and removing CO2 in the yellow phosphorus tail gas to below 50mg/Nm 3;
s2, preparing sodium formate: adding the decarburized yellow phosphorus tail gas and a NaOH solution into a synthesis reaction tower, and reacting at 150-200 ℃ and 1.8MPa to generate sodium formate with the concentration of 36-37%; evaporating the sodium formate solution in vacuum, concentrating the content of sodium formate in the sodium formate solution to 75% on average, cooling and crystallizing, and separating to obtain solid sodium formate with the water content of 5%;
S3, preparing sodium oxalate: sending the solid sodium formate obtained in the S2 into a dehydrogenation tower, heating by using circulating nitrogen at 400-420 ℃ for decomposition and dehydrogenation, enabling the temperature of the circulating nitrogen containing hydrogen and powdered sodium oxalate to be about 300 ℃, enabling the circulating nitrogen and the powdered sodium oxalate to enter a heat exchanger for heat exchange with low-temperature circulating nitrogen and rise to more than 150 ℃, enabling the circulating nitrogen and the powdered sodium oxalate to enter a catalytic combustor, adding air for combustion, rising the temperature to 400-420 ℃ for returning use, washing the circulating nitrogen containing hydrogen and the powdered oxalic acid by using water after heat exchange, and cooling at the same time to prepare suspension with the sodium oxalate content of 400 kg/m 3;
S4, preparation of calcium oxalate: lime is used as a precipitator to convert sodium oxalate into calcium oxalate precipitate;
S5, acidifying by calcium oxalate: calcium oxalate enters an acidification tank, sulfuric acid is added for acidification reaction to generate gypsum and crude oxalic acid, a filter is used for filtering, filter residues are gypsum and are discharged, and filtrate is crude oxalic acid;
s6, removing sulfate radicals in the crude oxalic acid: feeding the crude oxalic acid into a barium tank, adding a barium hydroxide suspension, generating a barium sulfate precipitate with excessive sulfate radicals, and filtering the precipitate;
s7, removing cations in oxalic acid: performing ion exchange with strong acid cation resin to remove cations in the crude oxalic acid solution,
Obtaining purified oxalic acid solution;
S8, preparing oxalic acid: the refined oxalic acid is subjected to vacuum multi-effect evaporation, so that the temperature of the oxalic acid solution is reduced, and the oxalic acid is prevented from being decomposed; oxalic acid is concentrated to 55 percent, the solution is cooled to 20 ℃, crystallized and separated, and the oxalic acid product is obtained after drying and dehydration.
2. The method for preparing oxalic acid by using the yellow phosphorus tail gas as claimed in claim 1, which is characterized in that: pressurizing to 2MPa when removing CO2 in S1, washing with water, removing CO2 to be below 0.5%, then washing with 2-3% dilute alkali liquor, and removing CO2 in the purified yellow phosphorus tail gas to be below 50mg/Nm 3.
3. The method for preparing oxalic acid by using the yellow phosphorus tail gas as claimed in claim 1, which is characterized in that: s4, specifically, putting the sodium oxalate suspension in a calcification tank, adding lime slurry into the calcification tank according to the concentration of 14% in proportion, wherein the proportion of the sodium oxalate to the lime is (COONa): CaO = 1: 1.15; the reaction time is 2 h; the concentration of the alkali liquor is 80-100 g/L.
4. the method for preparing oxalic acid by using the yellow phosphorus tail gas as claimed in claim 1, which is characterized in that: and (3) in S5, feeding calcium oxalate into an acidification tank, wherein the feeding ratio is H2SO 4: CaC2O4=1.25 (molar ratio), adding sulfuric acid with initial concentration of 28-30%; the reaction time is 1 h.
5. The method for preparing oxalic acid by using the yellow phosphorus tail gas as claimed in claim 1, which is characterized in that: s6, removing sulfate radical from coarse oxalic acid, which is to prepare barium hydroxide with 10-15% concentration with hot condensed water, add it into coarse oxalic acid solution while stirring to generate barium sulfate precipitate until no sulfate radical is detected with barium chloride solution.
6. The method for preparing oxalic acid by using the yellow phosphorus tail gas as claimed in claim 1, which is characterized in that: the specific operation in S7 is that fixed bed ion exchange column is used for dynamic operation, ion exchange resin is not used, solution flows through ion exchange resin under flowing for ion exchange, and cation is trapped in the resin to obtain purified oxalic acid.
7. the method for preparing oxalic acid by using the yellow phosphorus tail gas as claimed in claim 6, which is characterized in that: s7 the cations are Ca2+, Al3+, Fe3+, As3+, Hg2+ and Pb 2.
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| CN104610087A (en) * | 2014-11-28 | 2015-05-13 | 西南化工研究设计院有限公司 | Device and method for purifying yellow phosphorus tail gas and continuously synthesizing oxamide |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104610087A (en) * | 2014-11-28 | 2015-05-13 | 西南化工研究设计院有限公司 | Device and method for purifying yellow phosphorus tail gas and continuously synthesizing oxamide |
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| 刘兴勇等: "黄磷尾气的净化工艺与综合利用", 《现代化工》 * |
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