CN113735313A - Rare earth extraction wastewater zero-discharge treatment technology - Google Patents
Rare earth extraction wastewater zero-discharge treatment technology Download PDFInfo
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Abstract
The invention discloses a rare earth extraction wastewater zero-discharge treatment technology, which comprises the following steps: oil removal: deoiling the rare earth extraction wastewater to obtain deoiled wastewater; removing COD by an oxidation method: removing COD in the deoiled wastewater by adopting an oxidation method to obtain COD standard wastewater; removing heavy metals: introducing hydrogen sulfide gas into the COD standard wastewater to precipitate heavy metals in the COD standard wastewater, and filtering to remove the heavy metals to obtain heavy metal-removed wastewater; and (3) pH adjustment: adjusting the pH value of the heavy metal removal wastewater to convert ammonia nitrogen in the heavy metal removal wastewater into ammonia gas to obtain ammonia gas-containing wastewater; and (3) membrane deamination: and removing ammonia nitrogen from the ammonia-containing wastewater by a membrane deamination method, namely finishing zero-emission treatment of the rare earth extraction wastewater. The treatment technology not only effectively removes the components of oil, COD, heavy metal, ammonia nitrogen and the like in the rare earth extraction wastewater, but also realizes the recycling of the oil and the ammonia nitrogen, and really realizes the zero emission of the rare earth extraction wastewater.
Description
Technical Field
The invention relates to the technical field of wastewater discharge. In particular to a rare earth extraction wastewater zero-discharge treatment technology.
Background
A large amount of extraction wastewater is generated in the rare earth extraction process, and the wastewater is characterized by high salt, high COD, heavy metal content and high ammonia nitrogen content, so that the rare earth extraction wastewater can be discharged or recycled after COD, ammonia nitrogen and heavy metal removal. At present, a large amount of medicaments are generally required to be added for treating the rare earth extraction wastewater, secondary pollution is caused, the recycling of resources in the wastewater cannot be realized, and the difficulty in treating the wastewater is further increased due to the presence of components such as oil extractants in the rare earth extraction wastewater.
Patent CN103964612B discloses a low concentration ammonia nitrogen waste water deamination treatment method of high COD, high salt, high heavy metal content, and it only uses the flocculation and precipitation method to get rid of COD and heavy metal, and this kind of method is limited to the removal effect of COD and heavy metal, does not carry out the degree of depth of COD and gets rid of, and is great to the impact of follow-up deamination membrane. The deamination membrane as a hydrophobic membrane is very easily polluted by solvents and oil substances in wastewater, so that the hydrophobicity of the membrane is ineffective.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to provide a rare earth extraction wastewater zero-discharge treatment technology to solve the problems of short service life of a hydrophobic membrane, incomplete wastewater treatment and the like when wastewater generated in the rare earth extraction process is treated by the hydrophobic membrane.
In order to solve the technical problems, the invention provides the following technical scheme:
a rare earth extraction wastewater zero-discharge treatment technology comprises the following steps:
(1) oil removal: deoiling the rare earth extraction wastewater to obtain deoiled wastewater;
(2) the oxidation method reduces COD: reducing COD in the deoiled wastewater by adopting an oxidation method to obtain COD standard-reaching wastewater;
(3) removing heavy metals: introducing hydrogen sulfide gas into the COD standard wastewater to precipitate heavy metals in the COD standard wastewater, and filtering to remove the heavy metals to obtain heavy metal-removed wastewater;
(4) and (3) pH adjustment: adjusting the pH value of the heavy metal removal wastewater to convert ammonium ions in the heavy metal removal wastewater into ammonia gas to obtain ammonia gas-containing wastewater;
(5) and (3) membrane deamination: and removing ammonia gas from the ammonia gas-containing wastewater by adopting a membrane deamination method, namely finishing zero-emission treatment of the rare earth extraction wastewater.
According to the rare earth extraction wastewater zero-discharge treatment technology, the oil removal in the step (1) comprises two stages of wastewater pretreatment and deep oil removal:
wastewater pretreatment: removing suspended impurities in the rare earth extraction wastewater by adopting a filtering method;
deep oil removal: removing the oil extractant in the pretreated rare earth extraction wastewater by using an oil removal adsorption material; in the finally obtained deoiled wastewater: the oil content is less than 1mg/L, and the COD content is 100-500 mg/L.
According to the rare earth extraction wastewater zero-discharge treatment technology, the oil removal adsorption material is an ORZ material, the oil extraction agent is recovered after the oil removal adsorption material is regenerated, and the recovered oil extraction agent is returned to the extraction section for recycling.
According to the rare earth extraction wastewater zero-discharge treatment technology, in the step (2), the oxidation method is an ozone catalytic oxidation method or a Fenton oxidation method, and the COD in the obtained wastewater reaching the standard is as follows: the COD content is less than 60 mg/L.
According to the rare earth extraction wastewater zero-discharge treatment technology, in the catalytic ozonation method, the mass ratio of ozone to COD is (1-5): 1.
according to the rare earth extraction wastewater zero-discharge treatment technology, in the step (3), the introduction amount of the hydrogen sulfide gas is as follows: the molar ratio of hydrogen sulfide to heavy metal ions is (0.5-3): 1; in the obtained heavy metal removal wastewater: the heavy metal content is less than 0.1 mg/L.
According to the rare earth extraction wastewater zero-discharge treatment technology, in the step (4), the pH value of the heavy metal removal wastewater is adjusted by using an alkali liquor, so that the pH value of the heavy metal removal wastewater is within the range of 10-12; the alkali liquor is a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 10-30 wt%.
According to the rare earth extraction wastewater zero-discharge treatment technology, in the step (5), the method for removing ammonia nitrogen by using the membrane deamination method comprises the following steps:
step (5-1): filtering the ammonia-containing wastewater by an ultrafiltration membrane unit, conveying the filtered ammonia-containing wastewater to the inside of membrane filaments of a deamination membrane assembly, and conveying sulfuric acid or hydrochloric acid serving as absorption liquid to the outside of the membrane filaments; ammonia gas in the membrane filaments penetrates through the membrane filaments, enters the outside of the membrane filaments and reacts with the absorption liquid to generate ammonium chloride or ammonium sulfate; the mass concentration of the sulfuric acid or the hydrochloric acid is 15-25 wt%;
step (5-2): the absorption liquid outside the membrane filaments is recycled, when the mass concentration of the generated ammonium chloride or ammonium sulfate is more than or equal to 15 wt%, the recycling of the absorption liquid is stopped and recovered to obtain ammonium chloride or ammonium sulfate solution; and simultaneously supplementing a sulfuric acid or hydrochloric acid solution with the mass concentration of 15-25 wt% as an absorption liquid to continuously and circularly absorb the ammonia gas until the ammonia nitrogen in the ammonia gas-containing wastewater is removed.
According to the rare earth extraction wastewater zero-discharge treatment technology, in the step (5), a membrane deamination system is adopted to remove ammonia nitrogen in the ammonia-containing wastewater; the membrane deamination system comprises an ultrafiltration prefilter unit and a deamination membrane unit, and a liquid outlet of the ultrafiltration prefilter unit is communicated with a liquid inlet fluid in a membrane wire of the deamination membrane unit.
According to the rare earth extraction wastewater zero-discharge treatment technology, the ultrafiltration pre-filtration unit comprises a cartridge filter and an ultrafiltration membrane component, and the cartridge filter and the ultrafiltration membrane component are used for filtering impurities before deamination; the ammonia-removing membrane unit comprises a ammonia-removing membrane component, a waste water storage tank and an absorption liquid storage tank, wherein the ammonia-removing membrane component consists of a membrane shell and hollow fiber membrane filaments, ammonia-containing waste water enters the hollow fiber membrane filaments from the waste water storage tank from top to bottom and is discharged from a liquid outlet at the bottom, the absorption liquid enters the outer parts of the hollow fiber membrane filaments from the absorption liquid storage tank from bottom to top, and the absorption liquid returns to the absorption liquid storage tank for circulation; valves are respectively arranged on the circulating pipelines close to the membrane wire outer liquid inlet and the membrane wire outer liquid outlet so as to supplement absorption liquid and discharge the absorption liquid.
The technical scheme of the invention achieves the following beneficial technical effects:
1. the invention provides a multi-process coupling technology for zero discharge treatment of rare earth extraction wastewater, which truly realizes zero discharge and recycling of the rare earth extraction wastewater aiming at the characteristics of high salt, high COD, high ammonia nitrogen, heavy metal content and the like of the rare earth extraction wastewater; the technology has no discharge of pollutants, extractant oil enriched in an oil removal section can be returned to an extraction section for recycling, no pollutants are introduced in an advanced oxidation section, sulfide slag generated in a heavy metal removal section is finally recovered in a sulfide precipitation mode, an ammonia-removing membrane is used for purifying ammonia nitrogen in wastewater into high-purity ammonium chloride or ammonium sulfate, and the residual sodium chloride or sodium sulfate solution can be evaporated or subjected to acid-base regeneration.
2. The traditional rare earth high ammonia nitrogen wastewater usually uses ammonia distillation and stripping rectification methods to remove ammonia nitrogen in the wastewater, and the technologies usually have the characteristics of large steam consumption, high energy consumption and the like.
3. When the hydrophobic membrane is used for treating ammonia nitrogen in wastewater, the hydrophobic membrane is easily impacted and polluted by substances such as solvents, oils and the like in the wastewater, so that the hydrophobicity of the membrane is invalid, and the service life of the hydrophobic membrane is shortened. Before ammonia nitrogen is treated, the method thoroughly removes oil, COD, heavy metals, suspended impurities and the like in the wastewater, reduces the impact of the impurities in the wastewater on the hydrophobic membrane to the maximum extent, and greatly prolongs the service life of the hydrophobic membrane.
4. The treatment technology can be used for treating wastewater with COD content of 500-5000mg/L, oil content of 10-100mg/L, ammonia nitrogen content of 1000-5000mg/L and TDS content of 50-150g/L, and the treated rare earth extraction wastewater has heavy metal content of less than 0.1mg/mL, COD content of less than 60mg/L, oil content of less than 1mg/mL, and the service life of the membrane can reach more than 5 years. The treatment technology not only effectively removes the components of oil, COD, heavy metal, ammonia nitrogen and the like in the rare earth extraction wastewater, but also realizes the recycling of the oil and the ammonia nitrogen, and really realizes the zero emission of the rare earth extraction wastewater.
5. In the technical scheme of the invention, the oil content in the rare earth extraction wastewater is reduced to less than 1mg/L, COD and reduced to 100-500 mg/L through oil removal treatment; if the content of oil and COD after oil removal treatment can not be reduced to the range, the treatment effect of reducing COD by a subsequent oxidation method can be influenced, so that the technical aim of effectively reducing the impact of the rare earth extraction wastewater on a hydrophobic membrane in the subsequent membrane deamination process can not be achieved; the content of COD is further reduced by an oxidation method to make the content of the COD less than 60mg/L, and the reason is found in practice that the subsequent heavy metal removal effect is more favorably improved when the content of oil in the rare earth extraction wastewater is reduced to the content of less than 1mg/L, COD to the content of less than 60mg/L before heavy metal removal; in addition, when the content of oil is reduced to <1mg/L, COD and the content of heavy metal is reduced to <60mg/L and 0.1mg/L before the membrane deamination process, the impact on the membrane is small in the membrane deamination process, and the service life of the membrane is further favorably prolonged.
Drawings
FIG. 1 is a flow chart of the rare earth extraction wastewater zero-discharge treatment technology.
Detailed Description
Example 1
Rare earth extraction wastewater generated by a certain enterprise is treated by adopting a rare earth extraction wastewater zero-discharge treatment technology, wherein in the rare earth extraction wastewater: COD is 500mg/L, oil content is 10mg/L, ammonia nitrogen content is 1000mg/L, total dissolved solid TDS is 50g/L, heavy metal Pb is 10mg/L, As is 1.2 mg/L; the specific operation method comprises the following steps:
(1) oil removal: deoiling the rare earth extraction wastewater to obtain deoiled wastewater; the oil removal comprises two stages of wastewater pretreatment and deep oil removal: the wastewater pretreatment is to remove suspended impurities in the rare earth extraction wastewater by adopting a filtering method; deep degreasing is to remove oil extractant in pretreated rare earth extraction wastewater by using a degreasing adsorption material ORZ material (see Chinese patent document CN113083256A for details). After the oil is removed in the step (1), removing oil from the wastewater: the oil content is 0.1mg/L, and the COD content is 120 mg/L; in the oil removing process, because the oil is an organic matter, after most of the oil is removed, the COD value is naturally reduced, and if the COD is directly removed by an oxidation method without oil removing treatment, the COD removing cost is greatly increased due to the existence of the oil;
(2) the oxidation method reduces COD: reducing COD in the deoiled wastewater by adopting an ozone catalytic oxidation method to obtain COD standard-reaching wastewater; the mass ratio of ozone to COD is 1: 1; after the treatment of the step (2), the COD content in the COD-reaching wastewater is 55 mg/L;
(3) removing heavy metals: introducing hydrogen sulfide gas into the COD standard wastewater to precipitate heavy metals in the COD standard wastewater, and filtering to remove the heavy metals to obtain heavy metal-removed wastewater; the introduction amount of the hydrogen sulfide gas is as follows: the molar ratio of hydrogen sulfide to heavy metal ions is 1: 1; after the treatment of the step (3), Pb is less than 0.1mg/L, As is less than 0.05 mg/L;
(4) and (3) pH adjustment: adjusting the pH of the heavy metal removal wastewater to convert ammonium ions in the heavy metal removal wastewater into ammonia gas to obtain ammonia gas-containing wastewater, wherein the alkali liquor is NaOH solution, the concentration of the alkali liquor is 10 wt%, and the pH of the ammonia gas-containing wastewater is 10 after the pH is adjusted;
(5) and (3) membrane deamination: and removing ammonia gas from the ammonia-containing wastewater by adopting a membrane deamination method, namely finishing zero-emission treatment of the rare earth extraction wastewater. After the treatment of the step (5), the ammonia nitrogen content in the wastewater is less than 10mg/L, and the content of dissolved total solid TDS is 48 g/L. The deamination wastewater mainly contains sodium chloride or sodium sulfate, and can be recycled through evaporation or acid-base regeneration, so that the aim of zero discharge of the rare earth extraction wastewater is fulfilled.
The method for removing ammonia nitrogen by the membrane deamination method comprises the following steps:
step (5-1): filtering the ammonia-containing wastewater by an ultrafiltration membrane unit, conveying the filtered ammonia-containing wastewater to the inside of membrane filaments of a deamination membrane assembly, and conveying sulfuric acid serving as absorption liquid to the outside of the membrane filaments; ammonia gas in the membrane filaments penetrates through the membrane filaments and enters the outside of the membrane filaments to react with the absorption liquid to generate ammonium sulfate; the mass concentration of the sulfuric acid is 15 wt%;
step (5-2): the absorption liquid outside the membrane filaments is recycled, and when the mass concentration of the generated ammonium sulfate is more than 15 wt%, the recycling of the absorption liquid is stopped and recovered to obtain an ammonium sulfate solution; and meanwhile, supplementing a sulfuric acid solution with the mass concentration of 15 wt% as an absorption liquid to continuously and circularly absorb ammonia gas until the ammonia nitrogen in the ammonia gas-containing wastewater is less than 10 mg/L. In this example, the mass concentration of ammonium sulfate in the finally recovered absorption solution was 16 wt%, and the final absorption solution was evaporated to obtain high-purity ammonium sulfate with a purity of > 99%, which was sold as an ammonium sulfate product or used as an ammonia fertilizer.
In the embodiment, a membrane deamination system is adopted to remove ammonia nitrogen in the ammonia-containing wastewater; the membrane deamination system comprises an ultrafiltration prefilter unit and a deamination membrane unit, and a liquid outlet of the ultrafiltration prefilter unit is communicated with a liquid inlet fluid in a membrane wire of the deamination membrane unit. The ultrafiltration pre-filtering unit comprises a security filter and an ultrafiltration membrane component which are used for filtering impurities before the deamination membrane; the ammonia-removing membrane unit comprises a ammonia-removing membrane component, a waste water storage tank and an absorption liquid storage tank, wherein the ammonia-removing membrane component consists of a membrane shell and hollow fiber membrane filaments, ammonia-containing waste water enters the hollow fiber membrane filaments from the waste water storage tank from top to bottom and is discharged from a liquid outlet at the bottom, the absorption liquid enters the outer parts of the hollow fiber membrane filaments from the absorption liquid storage tank from bottom to top, and the absorption liquid returns to the absorption liquid storage tank for circulation; valves are respectively arranged on the circulating pipelines close to the membrane wire outer liquid inlet and the membrane wire outer liquid outlet so as to supplement absorption liquid and discharge the absorption liquid.
When the treatment technology of the embodiment is adopted to treat the rare earth extraction wastewater, the removal rate of oil is 99%, the removal rate of heavy metal Pb is more than 99%, the removal rate of As is more than 95.8%, the removal rate of COD is 89%, and the removal rate of ammonia nitrogen is more than 99%; the service life of the deamination film in the embodiment can reach more than 5 years.
Example 2
Rare earth extraction wastewater generated by a certain enterprise is treated by adopting a rare earth extraction wastewater zero-discharge treatment technology, wherein in the rare earth extraction wastewater: COD is 5000mg/L, oil content is 100mg/L, ammonia nitrogen content is 5000mg/L, total dissolved solid TDS is 150g/L, heavy metal Pb is 30mg/L, As is 5mg/L, Mn is 1.2 mg/L; the specific operation method comprises the following steps:
(1) oil removal: deoiling the rare earth extraction wastewater to obtain deoiled wastewater; the oil removal comprises two stages of wastewater pretreatment and deep oil removal: the wastewater pretreatment is to remove suspended impurities in the rare earth extraction wastewater by adopting a filtering method; deep degreasing is to remove oil extractant in pretreated rare earth extraction wastewater by using a degreasing adsorption material ORZ material (see Chinese patent document CN113083256A for details). After the oil is removed in the step (1), removing oil from the wastewater: the oil content is 0.8mg/L, and the COD content is 500 mg/L;
(2) the oxidation method reduces COD: reducing COD in the deoiled wastewater by adopting an ozone catalytic oxidation method to obtain COD standard-reaching wastewater; the mass ratio of ozone to COD is 5: 1; after the treatment of the step (2), the COD content in the COD-reaching wastewater is 60 mg/L;
(3) removing heavy metals: introducing hydrogen sulfide gas into the COD standard wastewater to precipitate heavy metals in the COD standard wastewater, and filtering to remove the heavy metals to obtain heavy metal-removed wastewater; the introduction amount of the hydrogen sulfide gas is as follows: the molar ratio of hydrogen sulfide to heavy metal ions is 3: 1; after the treatment of the step (3), Pb is less than 0.1mg/L, As is less than 0.05mg/L, and Mn is less than 0.1 mg/L;
(4) and (3) pH adjustment: adjusting the pH of the heavy metal removal wastewater to convert ammonium ions in the heavy metal removal wastewater into ammonia gas to obtain ammonia gas-containing wastewater, wherein the alkali liquor is a NaOH solution, the concentration of the alkali liquor is 20 wt%, and the pH of the ammonia gas-containing wastewater is 12 after the pH is adjusted;
(5) and (3) membrane deamination: and removing ammonia gas from the ammonia gas-containing wastewater by adopting a membrane deamination method, namely finishing zero-emission treatment of the rare earth extraction wastewater. After the treatment of the step (5), the ammonia nitrogen content in the wastewater is less than 10mg/L, and the content of soluble total solid TDS is 145 g/L. The deamination wastewater mainly contains sodium chloride or sodium sulfate, and can be recycled through evaporation or acid-base regeneration, so that the aim of zero discharge of the rare earth extraction wastewater is fulfilled.
The method for removing ammonia nitrogen by the membrane deamination method comprises the following steps:
step (5-1): filtering the ammonia-containing wastewater by an ultrafiltration membrane unit, conveying the filtered ammonia-containing wastewater to the inside of membrane filaments of a deamination membrane assembly, and conveying sulfuric acid serving as absorption liquid to the outside of the membrane filaments; ammonia gas in the membrane filaments penetrates through the membrane filaments and enters the outside of the membrane filaments to react with the absorption liquid to generate ammonium sulfate; the mass concentration of the sulfuric acid is 25 wt%;
step (5-2): the absorption liquid outside the membrane filaments is recycled, and when the mass concentration of the generated ammonium sulfate is more than 15 wt%, the recycling of the absorption liquid is stopped and recovered to obtain an ammonium sulfate solution; and meanwhile, supplementing a sulfuric acid solution with the mass concentration of 25 wt% as an absorption liquid to continuously and circularly absorb ammonia gas until the ammonia nitrogen in the ammonia gas-containing wastewater is less than 10 mg/L. In this example, the mass concentration of ammonium sulfate in the finally recovered absorption liquid was 25 wt%. The high-purity ammonium sulfate is obtained by evaporation, the purity of the ammonium sulfate is more than 99 percent, and the ammonium sulfate can be sold as an ammonium sulfate product and also can be used as an ammonia fertilizer.
In the embodiment, a membrane deamination system is adopted to remove ammonia nitrogen in the ammonia-containing wastewater; the membrane deamination system comprises an ultrafiltration prefilter unit and a deamination membrane unit, and a liquid outlet of the ultrafiltration prefilter unit is communicated with a liquid inlet fluid in a membrane wire of the deamination membrane unit. The ultrafiltration pre-filtering unit comprises a security filter and an ultrafiltration membrane component which are used for filtering impurities before the deamination membrane; the ammonia-removing membrane unit comprises a ammonia-removing membrane component, a waste water storage tank and an absorption liquid storage tank, wherein the ammonia-removing membrane component consists of a membrane shell and hollow fiber membrane filaments, ammonia-containing waste water enters the hollow fiber membrane filaments from the waste water storage tank from top to bottom and is discharged from a liquid outlet at the bottom, the absorption liquid enters the outer parts of the hollow fiber membrane filaments from the absorption liquid storage tank from bottom to top, and the absorption liquid returns to the absorption liquid storage tank for circulation; valves are respectively arranged on the circulating pipelines close to the membrane wire outer liquid inlet and the membrane wire outer liquid outlet so as to supplement absorption liquid and discharge the absorption liquid.
When the treatment technology of the embodiment is adopted to treat the rare earth extraction wastewater, the removal rate of oil is 99.2%, the removal rate of heavy metal Pb is more than 99.7%, the removal rate of As is more than 99%, the removal rate of Mn is more than 91.7%, the removal rate of COD is 98.8%, and the removal rate of ammonia nitrogen is more than 99.8%; the service life of the deamination film in the embodiment can reach more than 5 years.
Example 3
Rare earth extraction wastewater generated by a certain enterprise is treated by adopting a rare earth extraction wastewater zero-discharge treatment technology, wherein in the rare earth extraction wastewater: COD is 2000mg/L, oil content is 40mg/L, ammonia nitrogen content is 3000mg/L, total dissolved solids TDS is 80g/L, heavy metal Pb is 18mg/L, As is 3mg/L, Mn is 1.2 mg/L; the specific operation method comprises the following steps:
(1) oil removal: deoiling the rare earth extraction wastewater to obtain deoiled wastewater; the oil removal comprises two stages of wastewater pretreatment and deep oil removal: the wastewater pretreatment is to remove suspended impurities in the rare earth extraction wastewater by adopting a filtering method; deep degreasing is to remove oil extractant in pretreated rare earth extraction wastewater by using a degreasing adsorption material ORZ material (see Chinese patent document CN113083256A for details). After the oil is removed in the step (1), removing oil from the wastewater: the oil content is 0.4mg/L, and the COD content is 400 mg/L;
(2) the oxidation method reduces COD: reducing COD in the deoiled wastewater by adopting an ozone catalytic oxidation method to obtain COD standard-reaching wastewater; the mass ratio of ozone to COD is 4: 1; after the treatment of the step (2), the COD content in the COD-reaching wastewater is 55 mg/L;
(3) removing heavy metals: introducing hydrogen sulfide gas into the COD standard wastewater to precipitate heavy metals in the COD standard wastewater, and filtering to remove the heavy metals to obtain heavy metal-removed wastewater; the introduction amount of the hydrogen sulfide gas is as follows: the molar ratio of hydrogen sulfide to heavy metal ions is 2: 1; after the treatment of the step (3), Pb is less than 0.1mg/L, As is less than 0.05mg/L, and Mn is less than 0.1 mg/L;
(4) and (3) pH adjustment: adjusting the pH of the heavy metal removal wastewater to convert ammonium ions in the heavy metal removal wastewater into ammonia gas to obtain ammonia gas-containing wastewater, wherein the alkali liquor is NaOH solution, the concentration of the alkali liquor is 30 wt%, and the pH of the ammonia gas-containing wastewater is 11 after the pH is adjusted;
(5) and (3) membrane deamination: and removing ammonia gas from the ammonia gas-containing wastewater by adopting a membrane deamination method, namely finishing zero-emission treatment of the rare earth extraction wastewater. After the treatment of the step (5), the ammonia nitrogen content in the wastewater is less than 10mg/L, and the content of dissolved total solid TDS is 76 g/L. The deamination wastewater mainly contains sodium chloride or sodium sulfate, and can be recycled through evaporation or acid-base regeneration, so that the aim of zero discharge of the rare earth extraction wastewater is fulfilled.
The method for removing ammonia nitrogen by the membrane deamination method comprises the following steps:
step (5-1): filtering the ammonia-containing wastewater by an ultrafiltration membrane unit, conveying the filtered ammonia-containing wastewater to the inside of membrane filaments of a deamination membrane assembly, and conveying hydrochloric acid serving as absorption liquid to the outside of the membrane filaments; ammonia gas in the membrane filaments penetrates through the membrane filaments and enters the outside of the membrane filaments to react with the absorption liquid to generate ammonium chloride; the mass concentration of the hydrochloric acid is 15 wt%;
step (5-2): recycling the absorption liquid outside the membrane filaments, and stopping recycling the absorption liquid and recycling the absorption liquid to obtain an ammonium chloride solution when the mass concentration of the generated ammonium chloride is more than 15 wt%; and meanwhile, a hydrochloric acid solution with the mass concentration of 15 wt% is supplemented to serve as an absorption liquid to continuously and circularly absorb ammonia gas until the ammonia nitrogen in the ammonia gas-containing wastewater is less than 10 mg/L. In this example, the mass concentration of ammonium chloride in the finally recovered absorbing solution was 15 wt%. The high-purity ammonium chloride is obtained by evaporation, the purity of the ammonium chloride is more than 99 percent, and the ammonium chloride can be sold as an ammonium chloride product and also can be used as an ammonia fertilizer.
In the embodiment, a membrane deamination system is adopted to remove ammonia nitrogen in the ammonia-containing wastewater; the membrane deamination system comprises an ultrafiltration prefilter unit and a deamination membrane unit, and a liquid outlet of the ultrafiltration prefilter unit is communicated with a liquid inlet fluid in a membrane wire of the deamination membrane unit. The ultrafiltration pre-filtering unit comprises a security filter and an ultrafiltration membrane component which are used for filtering impurities before the deamination membrane; the ammonia-removing membrane unit comprises a ammonia-removing membrane component, a waste water storage tank and an absorption liquid storage tank, wherein the ammonia-removing membrane component consists of a membrane shell and hollow fiber membrane filaments, ammonia-containing waste water enters the hollow fiber membrane filaments from the waste water storage tank from top to bottom and is discharged from a liquid outlet at the bottom, the absorption liquid enters the outer parts of the hollow fiber membrane filaments from the absorption liquid storage tank from bottom to top, and the absorption liquid returns to the absorption liquid storage tank for circulation; valves are respectively arranged on the circulating pipelines close to the membrane wire outer liquid inlet and the membrane wire outer liquid outlet so as to supplement absorption liquid and discharge the absorption liquid.
When the treatment technology of the embodiment is adopted to treat the rare earth extraction wastewater, the removal rate of oil is 99%, the removal rate of heavy metal Pb is more than 99.9%, the removal rate of As is more than 98.3%, the removal rate of Mn is more than 91.7%, the removal rate of COD is 97.3%, the removal rate of ammonia nitrogen reaches more than 99.7%, and the service life of the deamination membrane in the embodiment can reach more than 5 years.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications are possible which remain within the scope of the appended claims.
Claims (10)
1. A rare earth extraction wastewater zero-discharge treatment technology is characterized by comprising the following steps:
(1) oil removal: deoiling the rare earth extraction wastewater to obtain deoiled wastewater;
(2) the oxidation method reduces COD: reducing COD in the deoiled wastewater by adopting an oxidation method to obtain COD standard-reaching wastewater;
(3) removing heavy metals: introducing hydrogen sulfide gas into the COD standard wastewater to precipitate heavy metals in the COD standard wastewater, and filtering to remove the heavy metals to obtain heavy metal-removed wastewater;
(4) and (3) pH adjustment: adjusting the pH value of the heavy metal removal wastewater to convert ammonium ions in the heavy metal removal wastewater into ammonia gas to obtain ammonia gas-containing wastewater;
(5) and (3) membrane deamination: and removing ammonia gas from the ammonia gas-containing wastewater by adopting a membrane deamination method, namely finishing zero-emission treatment of the rare earth extraction wastewater.
2. The rare earth extraction wastewater zero emission treatment technology according to claim 1, wherein the oil removal in the step (1) comprises two stages of wastewater pretreatment and deep oil removal:
wastewater pretreatment: removing suspended impurities in the rare earth extraction wastewater by adopting a filtering method;
deep oil removal: removing the oil extractant in the pretreated rare earth extraction wastewater by using an oil removal adsorption material; in the finally obtained deoiled wastewater: the oil content is less than 1mg/L, and the COD content is 100-500 mg/L.
3. The rare earth extraction wastewater zero-emission treatment technology according to claim 2, wherein the oil removal adsorption material is an ORZ material, the oil removal adsorption material is regenerated to recover the oil extractant, and the recovered oil extractant is returned to the extraction section for recycling.
4. The rare earth extraction wastewater zero emission treatment technology according to claim 1, wherein in the step (2), the oxidation method is an ozone catalytic oxidation method or a Fenton oxidation method, and the obtained COD-qualified wastewater is treated by: the COD content is less than 60 mg/L.
5. The rare earth extraction wastewater zero emission treatment technology according to claim 4, wherein in the catalytic ozonation process, the mass ratio of ozone to COD is (1-5): 1.
6. the rare earth extraction wastewater zero-emission treatment technology as claimed in claim 1, wherein in the step (3), the introduction amount of the hydrogen sulfide gas is as follows: the molar ratio of hydrogen sulfide to heavy metal ions is (0.5-3): 1; in the obtained heavy metal removal wastewater: the heavy metal content is less than 0.1 mg/L.
7. The rare earth extraction wastewater zero-emission treatment technology as claimed in claim 1, wherein in the step (4), the pH value of the heavy metal removal wastewater is adjusted by using alkaline liquor, so that the pH value of the heavy metal removal wastewater is within a range of 10-12; the alkali liquor is a sodium hydroxide solution, and the concentration of the sodium hydroxide solution is 10-30 wt%.
8. The rare earth extraction wastewater zero-emission treatment technology of claim 1, wherein in the step (5), the method for removing ammonia nitrogen by membrane deamination comprises the following steps:
step (5-1): filtering the ammonia-containing wastewater by an ultrafiltration membrane unit, conveying the filtered ammonia-containing wastewater to the inside of membrane filaments of a deamination membrane assembly, and conveying sulfuric acid or hydrochloric acid serving as absorption liquid to the outside of the membrane filaments; ammonia gas in the membrane filaments penetrates through the membrane filaments, enters the outside of the membrane filaments and reacts with the absorption liquid to generate ammonium chloride or ammonium sulfate; the mass concentration of the sulfuric acid or the hydrochloric acid is 15-25 wt%;
step (5-2): the absorption liquid outside the membrane filaments is recycled, when the mass concentration of the generated ammonium chloride or ammonium sulfate is more than or equal to 15 wt%, the recycling of the absorption liquid is stopped and recovered to obtain ammonium chloride or ammonium sulfate solution; and simultaneously supplementing a sulfuric acid or hydrochloric acid solution with the mass concentration of 15-25 wt% as an absorption liquid to continuously and circularly absorb the ammonia gas until the ammonia nitrogen in the ammonia gas-containing wastewater is removed.
9. The zero discharge treatment technology for rare earth extraction wastewater as claimed in claim 8, wherein in the step (5), a membrane deamination system is adopted to remove ammonia nitrogen in the ammonia-containing wastewater; the membrane deamination system comprises an ultrafiltration prefilter unit and a deamination membrane unit, and a liquid outlet of the ultrafiltration prefilter unit is communicated with a liquid inlet fluid in a membrane wire of the deamination membrane unit.
10. The zero discharge treatment technology for rare earth extraction wastewater as claimed in claim 9, wherein the ultrafiltration pre-filtration unit comprises a cartridge filter and an ultrafiltration membrane module, both of which are used for filtering impurities before deamination membrane; the ammonia-removing membrane unit comprises a ammonia-removing membrane component, a waste water storage tank and an absorption liquid storage tank, wherein the ammonia-removing membrane component consists of a membrane shell and hollow fiber membrane filaments, ammonia-containing waste water enters the hollow fiber membrane filaments from the waste water storage tank from top to bottom and is discharged from a liquid outlet at the bottom, the absorption liquid enters the outer parts of the hollow fiber membrane filaments from the absorption liquid storage tank from bottom to top, and the absorption liquid returns to the absorption liquid storage tank for circulation; valves are respectively arranged on the circulating pipelines close to the membrane wire outer liquid inlet and the membrane wire outer liquid outlet so as to supplement absorption liquid and discharge the absorption liquid.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115583745A (en) * | 2022-09-29 | 2023-01-10 | 江西盖亚环保科技有限公司 | Method and device for treating rare earth ammonia nitrogen wastewater |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090045135A1 (en) * | 2007-08-18 | 2009-02-19 | Khudenko Engineering, Inc. | Method for water filtration |
| US20120255904A1 (en) * | 2006-12-12 | 2012-10-11 | Veolia Water Solutions & Technologies Support | Method of Recovering Oil or Gas and Treating the Resulting Produced Water |
| CN103964612A (en) * | 2014-05-22 | 2014-08-06 | 北京赛科康仑环保科技有限公司 | Deaminizing treatment method of medium-concentration and low-concentration ammonia-nitrogen wastewater under high COD (Chemical Oxygen Demand), salt content and heavy metal content |
| CN107043192A (en) * | 2017-05-05 | 2017-08-15 | 北京中科康仑环境科技研究院有限公司 | A kind of integrated conduct method of Rare-earth Ammonia soap raffinate |
| CN110015795A (en) * | 2019-04-01 | 2019-07-16 | 河海大学 | The recycling and zero-discharge treatment system and technique of binary complex system nickel hydrometallurgy waste water with high salt |
| CN111392943A (en) * | 2019-11-29 | 2020-07-10 | 北京耀智环保科技有限公司 | Method for treating and recycling high-concentration ammonia nitrogen and COD sewage |
| CN113087319A (en) * | 2021-05-21 | 2021-07-09 | 北京赛科康仑环保科技有限公司 | System and method for treating rare earth or nonferrous smelting high-salt high-COD wastewater |
| CN113307438A (en) * | 2021-06-30 | 2021-08-27 | 赛恩斯环保股份有限公司 | Treatment method of nickel-cobalt smelting heavy metal wastewater |
-
2021
- 2021-09-07 CN CN202111042791.0A patent/CN113735313A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120255904A1 (en) * | 2006-12-12 | 2012-10-11 | Veolia Water Solutions & Technologies Support | Method of Recovering Oil or Gas and Treating the Resulting Produced Water |
| US20090045135A1 (en) * | 2007-08-18 | 2009-02-19 | Khudenko Engineering, Inc. | Method for water filtration |
| CN103964612A (en) * | 2014-05-22 | 2014-08-06 | 北京赛科康仑环保科技有限公司 | Deaminizing treatment method of medium-concentration and low-concentration ammonia-nitrogen wastewater under high COD (Chemical Oxygen Demand), salt content and heavy metal content |
| CN107043192A (en) * | 2017-05-05 | 2017-08-15 | 北京中科康仑环境科技研究院有限公司 | A kind of integrated conduct method of Rare-earth Ammonia soap raffinate |
| CN110015795A (en) * | 2019-04-01 | 2019-07-16 | 河海大学 | The recycling and zero-discharge treatment system and technique of binary complex system nickel hydrometallurgy waste water with high salt |
| CN111392943A (en) * | 2019-11-29 | 2020-07-10 | 北京耀智环保科技有限公司 | Method for treating and recycling high-concentration ammonia nitrogen and COD sewage |
| CN113087319A (en) * | 2021-05-21 | 2021-07-09 | 北京赛科康仑环保科技有限公司 | System and method for treating rare earth or nonferrous smelting high-salt high-COD wastewater |
| CN113307438A (en) * | 2021-06-30 | 2021-08-27 | 赛恩斯环保股份有限公司 | Treatment method of nickel-cobalt smelting heavy metal wastewater |
Non-Patent Citations (1)
| Title |
|---|
| 张学铭等编: "《化学小辞典 第2版》", 31 August 1994, 科学技术文献出版社, pages: 330 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115583745A (en) * | 2022-09-29 | 2023-01-10 | 江西盖亚环保科技有限公司 | Method and device for treating rare earth ammonia nitrogen wastewater |
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