CN106746402B - Method for treating arsenic-removing sludge - Google Patents
Method for treating arsenic-removing sludge Download PDFInfo
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- CN106746402B CN106746402B CN201611179880.9A CN201611179880A CN106746402B CN 106746402 B CN106746402 B CN 106746402B CN 201611179880 A CN201611179880 A CN 201611179880A CN 106746402 B CN106746402 B CN 106746402B
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- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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- C02F11/00—Treatment of sludge; Devices therefor
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
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- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
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Abstract
The invention discloses a method for treating arsenic-removing sludge, wherein the arsenic-removing sludge contains at least one of calcium carbonate, calcium hydroxide, ferric hydroxide and tungsten oxide, and the method comprises the following steps: (1) mixing the arsenic-removed sludge with water to obtain slurry; (2) mixing and dissolving the slurry with a first acid solution, and filtering to obtain a filtrate containing calcium ions and iron ions and a filter residue containing tungsten oxide; (3) mixing the tungsten smelting wastewater with a second acid solution and a filtrate containing calcium ions and iron ions, and filtering to obtain first arsenic-removing sludge and arsenic-removing filtrate; (4) and mixing the filter residue containing the tungsten oxide with alkali liquor and then filtering to obtain filtrate and filter residue containing tungstate. The method can reduce the amount of arsenic-removing sludge by more than 90 percent, reduce the amount of calcium salt and ferric salt added for removing arsenic in the tungsten smelting wastewater by more than 80 percent, ensure that the recovery rate of tungsten oxide reaches more than 85 percent, and has the advantages of low cost, simple equipment and easy operation process for realizing industrial application.
Description
Technical Field
The invention belongs to the field of resource recycling, and particularly relates to a method for treating arsenic-removing sludge.
Background
At present, the environment-friendly situation of tungsten smelting is increasingly severe. In 2016, 1 month, the national department of environmental protection lists tungsten smelting slag, molybdenum slag and waste water arsenic removal sludge as dangerous solid waste, so that the law of 'three slags' can be met if the treatment is slightly improper. How to effectively treat the 'three slags' becomes the most concerned thing of tungsten smelting enterprises at present. If the three slags are treated by a unit with dangerous waste treatment qualification, enterprises cannot bear the three slags due to very high treatment cost.
The tungsten smelting wastewater contains 3-7 mg/L arsenic as a main sludge factor, and the arsenic-removing sludge is mainly generated in the arsenic-removing process of the wastewater. The arsenic removal process mainly comprises a calcium salt precipitation method, an iron salt precipitation method or a calcium salt-iron salt combined precipitation method. At present, the calcium salt precipitation method and the iron salt precipitation method are greatly influenced by the pH value of wastewater and other impurity ions, so the arsenic removal effect is unstable; the calcium salt-iron salt combined precipitation method is the most stable method for removing arsenic from tungsten smelting wastewater, but can generate more arsenic-removing sludge. As for arsenic-containing sludge, the industry currently adopts the stabilization landfill, cement solidification or lime solidification treatment technology, i.e. all pollution components in the hazardous waste are rendered chemically inert or contained to reduce the subsequent treatment and potential danger.
Therefore, the existing technology for treating arsenic-removing sludge needs to be further improved.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, one purpose of the invention is to provide a method for treating arsenic-removing sludge, which can realize comprehensive recycling of resources such as calcium, iron, tungsten and the like in the arsenic-removing sludge, and the treatment method has the advantages of simple treatment equipment, simple and convenient operation process, convenient industrialization realization, low investment and contribution to improving the economic benefit of enterprises.
The present application was completed based on the following findings of the inventors: as the tungsten slag, the molybdenum slag and the waste water arsenic-removing sludge of tungsten smelting are listed as dangerous solid wastes, the treatment of the 'three slags' becomes important for tungsten smelting enterprises. For tungsten smelting enterprises, high treatment cost is spent, the three slags are treated by units with hazardous waste treatment quality, or the enterprises develop corresponding treatment processes to reach the corresponding national environmental protection emission standard. At present, the industry mostly adopts the stabilization landfill, cement solidification or lime solidification treatment technology for removing arsenic sludge from wastewater, i.e. all pollution components in the hazardous waste are rendered chemically inert or contained so as to reduce the subsequent treatment and potential danger. The method has the disadvantages that valuable metals in the arsenic-removing sludge cannot be recycled, and the use channel of the formed condensate is limited. In view of the above, the inventor of the present application actively explores the existing technology for treating arsenic-removing sludge, and aims to overcome the defects in the prior art, so as to obtain a treatment process which can effectively recycle valuable metals in arsenic-removing sludge, and has the advantages of simple treatment equipment, simple process and low production cost.
To this end, in one aspect of the invention, the invention provides a method of treating arsenic-removal sludge containing at least one of calcium carbonate, calcium hydroxide, iron hydroxide and tungsten oxide. According to an embodiment of the invention, the method comprises: (1) mixing the arsenic-removing sludge with water so as to obtain slurry; (2) mixing and dissolving the slurry liquid and a first acid liquid, and filtering to obtain a filtrate containing calcium ions and iron ions and a filter residue containing tungsten oxide; (3) mixing tungsten smelting wastewater with a second acid solution and the filtrate containing calcium ions and iron ions, filtering to obtain first arsenic-removing sludge and arsenic-removing filtrate, and returning the first arsenic-removing sludge to the step (1) for slurrying, wherein the tungsten smelting wastewater contains at least one of sodium hydroxide, sodium chloride, sodium arsenate, sodium silicate and tungsten oxide; (4) and mixing the filter residue containing the tungsten oxide with alkali liquor and then filtering to obtain filtrate and filter residue containing tungstate.
Therefore, the method for treating the arsenic-removing sludge according to the embodiment of the invention mixes the slurry liquid of the arsenic-removing sludge with the acid liquid, can convert calcium carbonate and ferric hydroxide contained in the arsenic-removing sludge into soluble calcium salt and ferric salt, so that filtrate containing calcium ions and iron ions and filter residue containing tungsten oxide can be obtained by filtering, then mixing the obtained filtrate containing calcium ions and iron ions with tungsten smelting wastewater as an arsenic removal reagent, wherein sodium arsenate in the tungsten smelting wastewater can be combined with the calcium ions and the iron ions in the filtrate to be converted into ferric arsenate and calcium arsenate, thereby not only effectively recycling valuable elements in the arsenic-removing sludge, but also obviously reducing the treatment cost of the tungsten smelting wastewater, the content of arsenic in the tungsten smelting wastewater can be obviously reduced, and the tungsten smelting wastewater can be discharged after reaching the standard after being subjected to defluorination and pH adjustment; meanwhile, arsenic-removing sludge obtained by separation in the tungsten smelting wastewater treatment process is returned to the step (1) for continuous use, iron salt and calcium salt in the part of arsenic-removing sludge can be continuously utilized, and then filter residue containing tungsten oxide obtained by separation in the step (2) is mixed with alkali liquor, and tungsten oxide can be converted into tungstate, so that the arsenic-removing sludge and tungsten element in tungsten smelting wastewater can be recycled, and in addition, the method for treating arsenic-removing sludge disclosed by the invention not only can reduce the amount of arsenic-removing sludge by more than 90%, but also can reduce the amount of calcium salt and iron salt added in the tungsten smelting wastewater for arsenic removal by more than 80%; the tungsten oxide can be effectively recovered by leaching the filter residue containing the tungsten oxide with alkali, and the recovery rate can reach more than 85 percent. Therefore, the method can realize the comprehensive recycling of resources such as calcium, iron, tungsten and the like in arsenic-removing sludge and tungsten smelting wastewater, and the treatment method has the advantages of simple treatment equipment, simple and convenient operation process, convenience for realizing industrialization, low investment and contribution to improving the economic benefit of enterprises.
In addition, the method for treating arsenic-removing sludge according to the above embodiment of the present invention may further have the following additional technical features:
in some embodiments of the invention, in the step (1), the mixing mass ratio of the water to the arsenic-removing sludge is (20-25): 1. therefore, the arsenic-removing sludge can be fully slurried.
In the step (1), the arsenic-removing sludge and the water are mixed and stirred for 0.3 to 1 hour, preferably 0.5 hour. Thus, the sludge from which arsenic has been removed can be made into a slurry sufficiently.
In some embodiments of the present invention, in the step (2), the first acid solution is at least one selected from hydrochloric acid and nitric acid. Therefore, the dissolution rate of calcium carbonate and ferric oxide in the arsenic-removing sludge can be obviously improved.
In some embodiments of the invention, in the step (2), the mass concentration of the first acid solution is 20-40%, preferably 31%. Therefore, the dissolution rate of calcium carbonate and ferric oxide in the arsenic-removing sludge can be further improved.
In some embodiments of the present invention, in the step (2), the mixing volume ratio of the slurry liquid to the first acid liquid is (15-25): 1. therefore, the dissolution rate of calcium carbonate and ferric oxide in the arsenic-removing sludge can be further improved.
In some embodiments of the present invention, in the step (2), the mixing and stirring time of the slurry and the first acid solution is 0.5 to 1.5 hours. Therefore, the dissolution rate of calcium carbonate and ferric oxide in the arsenic-removing sludge can be further improved.
In some embodiments of the invention, in the step (2), the mixing and stirring speed of the slurry and the first acid liquid is 30 to 100r/min, preferably 60 r/min. Therefore, the dissolution rate of calcium carbonate and ferric oxide in the arsenic-removing sludge can be further improved.
In some embodiments of the present invention, in step (3), the method further comprises: adding calcium salt and iron salt into the mixed solution of the tungsten smelting wastewater, the second acid solution and the filtrate containing calcium ions and iron ions. Therefore, the arsenic removal rate in the tungsten smelting wastewater can be obviously improved.
In some embodiments of the invention, in the step (3), the pH of the mixed solution containing the tungsten smelting wastewater and the second acid solution is 9.5 to 10.5. Therefore, the arsenic removal rate in the tungsten smelting wastewater can be further improved.
In some embodiments of the present invention, in the step (3), the second acid solution is at least one selected from hydrochloric acid and nitric acid. Therefore, the arsenic removal rate in the tungsten smelting wastewater can be further improved.
In some embodiments of the invention, in the step (3), the mixing volume ratio of the tungsten smelting wastewater to the filtrate containing calcium ions and iron ions is (15-25): 1. therefore, the arsenic removal rate in the tungsten smelting wastewater can be further improved.
In some embodiments of the invention, in the step (3), the tungsten smelting wastewater is mixed with the second acid solution and the filtrate containing calcium ions and iron ions for 5-10 minutes. Therefore, the arsenic removal rate in the tungsten smelting wastewater can be further improved.
In some embodiments of the invention, in step (3), the stirring is continued for 5 to 10 minutes after the calcium salt and the iron salt are added. Therefore, the arsenic removal rate in the tungsten smelting wastewater can be further improved.
In some embodiments of the present invention, in step (3), the calcium salt is at least one of calcium chloride, calcium nitrate, calcium carbonate and calcium sulfate, preferably calcium chloride and calcium nitrate, and the iron salt is at least one of ferric chloride, ferrous chloride, ferric sulfate and ferrous sulfate. Thereby, arsenic in the tungsten smelting wastewater can be further removed.
In some embodiments of the invention, in the step (3), the mixing ratio of the added calcium salt to the tungsten smelting wastewater is (0.025-0.05): 1. therefore, the arsenic removal rate in the tungsten smelting wastewater can be further improved.
In some embodiments of the invention, in the step (3), the mixing ratio of the supplemented iron salt to the tungsten smelting wastewater is (0.025-0.05): 1. therefore, the arsenic removal rate in the tungsten smelting wastewater can be further improved.
In some embodiments of the present invention, in the step (4), the alkali solution is at least one selected from the group consisting of sodium hydroxide and potassium hydroxide. This can improve the recovery rate of tungsten oxide.
In some embodiments of the invention, in the step (4), the weight ratio of the tungsten oxide-containing filter residue to the alkali liquor is (0.5-1.5): (1.5-2.5), preferably 1: 2. this can further improve the recovery rate of tungsten oxide.
In some embodiments of the invention, in the step (4), the mixing temperature of the tungsten oxide-containing filter residue and the alkali liquor is 120-150 ℃ and the mixing time is 3-6 hours. This can further improve the recovery rate of tungsten oxide.
In some embodiments of the present invention, in the steps (2) (3) (4), the filtration is at least one of vacuum suction filtration, centrifugal filtration and plate-and-frame filter-pressing, respectively and independently. Therefore, the comprehensive cyclic utilization of resources such as calcium, iron, tungsten and the like in the arsenic-removing sludge of the wastewater can be realized, the treatment process is simplified, and the industrial application is convenient to realize.
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The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
FIG. 1 is a schematic flow diagram of a method of treating arsenic removing sludge according to one embodiment of the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In one aspect of the invention, the invention provides a method for treating arsenic-removing sludge, wherein the arsenic-removing sludge contains at least one of calcium carbonate, calcium hydroxide, iron hydroxide and tungsten oxide. According to an embodiment of the invention, the method comprises: (1) mixing the arsenic-removing sludge with water so as to obtain slurry; (2) mixing and dissolving the slurry liquid and a first acid liquid, and filtering to obtain a filtrate containing calcium ions and iron ions and a filter residue containing tungsten oxide; (3) mixing tungsten smelting wastewater with a second acid solution and the filtrate containing calcium ions and iron ions, filtering to obtain first arsenic-removing sludge and arsenic-removing filtrate, and returning the first arsenic-removing sludge to the step (1) for slurrying, wherein the tungsten smelting wastewater contains at least one of sodium hydroxide, sodium chloride, sodium arsenate, sodium silicate and tungsten oxide; (4) and mixing the filter residue containing the tungsten oxide with alkali liquor and then filtering to obtain filtrate and filter residue containing tungstate. The inventor finds that calcium salt and ferric salt in the arsenic-removed sludge can be fully dissolved by slurrying the arsenic-removed sludge and then mixing the arsenic-removed sludge with the first acid solution, so that the amount of filter residue obtained after filtering is only 5-10 wt% of the total amount of the arsenic-removed sludge before acid dissolution, the amount of sludge is remarkably reduced, and 5-15 wt% of tungsten oxide is contained in the filter residue, thereby being beneficial to the recovery of subsequent tungsten oxide; the filtered filtrate contains a large amount of calcium salt and ferric salt, and can be used as an arsenic removal reagent in the tungsten smelting wastewater treatment process, so that the amount of the calcium salt and ferric salt which need to be supplemented for removing arsenic in the tungsten smelting wastewater can be greatly reduced, according to experiments, the supplementing amount of the calcium salt and ferric salt can be reduced by more than 80%, the arsenic content in the filtrate is greatly reduced by the arsenic removal process and is less than 0.1mg/L, and the filtrate can be discharged after reaching the standard after being subjected to fluorine removal and pH adjustment. The tungsten oxide is recovered by carrying out alkali leaching on the filter residue containing 5-15 wt% of tungsten oxide, and the recovery rate of the tungsten oxide can reach more than 85%. In the whole process, the recycling rate of calcium salt and ferric salt in the arsenic-removing sludge is high, the recovery rate of tungsten oxide is high, the arsenic-removing effect of the tungsten smelting wastewater is obvious, the process is environment-friendly and economical, the treatment process is simple, and the industrialization is convenient to realize.
The method for treating arsenic-removing sludge according to the embodiment of the present invention will be described in detail with reference to FIG. 1. According to an embodiment of the invention, the method comprises:
s100: mixing the arsenic-removing sludge with water
In this step, the arsenic removal sludge may contain at least one of calcium carbonate, calcium hydroxide, iron hydroxide and tungsten oxide, and specifically, the arsenic removal sludge may contain 2 wt% of magnesium oxide, 7 wt% of silicon oxide, 70 wt% of calcium carbonate, 11 wt% of calcium hydroxide, 8 wt% of iron hydroxide, 1.5 wt% of tungsten oxide, 0.5 wt% of arsenic oxide, and others. Specifically, the arsenic-removed sludge is mixed with water to obtain a slurry solution.
According to an embodiment of the present invention, the mixing ratio of water and arsenic-removing sludge in this step is not particularly limited, and may be selected by those skilled in the art according to actual needs, and according to an embodiment of the present invention, the mixing mass ratio of water and arsenic-removing sludge may be (20-25): 1. the inventor finds that when the mixing mass ratio of water and arsenic-removing sludge is too high, the obtained slurrying liquid is too much to be recycled, and the efficiency of treating the arsenic-removing sludge is reduced due to too much water; when the mixing mass ratio of the water to the arsenic-removing sludge is too low, the acidity of the slurry is too strong, so that the first acid solution and the second acid solution added subsequently are wasted, and the pH value of the first arsenic-removing sludge is too low.
According to another embodiment of the present invention, the mixing and stirring time of the arsenic-removing sludge and the water in the step is not particularly limited, and may be selected by those skilled in the art according to actual needs, and according to one embodiment of the present invention, the mixing and stirring time of the arsenic-removing sludge and the water may be 0.3 to 1 hour, preferably 0.5 hour. This makes it possible to further sufficiently slurry the arsenic-removed sludge.
S200: mixing and dissolving the slurry liquid and the first acid liquid, and filtering
In the step, the slurry obtained in the step is mixed with a first acid solution, stirred and filtered, so that filtrate containing calcium ions and iron ions and filter residue containing tungsten oxide are obtained. The inventor finds that by adding the first acid solution into the slurried arsenic-removing sludge and stirring while adding, insoluble calcium salt, iron salt and the like in the arsenic-removing sludge can be fully dissolved into the filtrate, so that the amount of filter residue obtained after filtering is only 5-10 wt% of the total amount of the arsenic-removing sludge before acid dissolution, the amount of sludge is remarkably reduced, and 5-15 wt% of tungsten oxide is contained in the filter residue obtained by separation, and the subsequent recovery of tungsten oxide is facilitated. The main chemical reaction equations involved in this step are shown below:
CaCO3+HCl＝CaCl2+H2O+CO2(1)
Ca(OH)2+HCl＝CaCl2+H2O (2)
Fe(OH)3+HCl＝FeCl3+H2O (3)
according to an embodiment of the present invention, the kind of the first acid solution is not particularly limited, and may be selected by those skilled in the art according to actual needs, and according to an embodiment of the present invention, the first acid solution may be at least one selected from hydrochloric acid and nitric acid. The inventor finds that the acid liquor can fully dissolve precipitates such as calcium salt, ferric salt and the like in the slurried arsenic-removing sludge, thereby remarkably reducing the sludge amount.
According to another embodiment of the present invention, the concentration of the first acid solution is not particularly limited, and may be selected by a person skilled in the art according to actual needs, and according to an embodiment of the present invention, the mass concentration of the first acid solution may be 20 to 40%, and preferably 31%. The inventor finds that the acid liquor with the concentration is obviously superior to other acid liquor with the concentration which can fully dissolve precipitates such as calcium salt, iron salt and the like in the slurried arsenic-removing sludge, thereby obviously reducing the sludge amount.
According to another embodiment of the present invention, the mixing ratio of the slurry and the first acid solution is not particularly limited, and may be selected by those skilled in the art according to actual needs, and according to an embodiment of the present invention, the mixing volume ratio of the slurry and the first acid solution may be (15-25): 1. the inventor finds that when the mixing volume ratio of the slurry and the first mixed acid is too high, the volume of the obtained filtrate is too large, the filtrate cannot be completely recycled, and the efficiency of treating the arsenic-removing sludge is reduced; when the mixing volume ratio of the slurry solution to the first mixed acid is too low, the acidity of the slurry solution is too strong, so that the second acid solution added subsequently is wasted, and the pH value of the first arsenic-removing sludge is too low.
According to another embodiment of the present invention, the mixing and stirring time of the slurry and the first acid solution is not particularly limited, and may be selected by those skilled in the art according to actual needs, and according to an embodiment of the present invention, the mixing and stirring time of the slurry and the first acid solution may be 0.5 to 1.5 hours. Therefore, the dissolving amount of precipitates such as calcium salt, iron salt and the like in the arsenic-removed sludge after slurrying can be remarkably increased, and the sludge amount is reduced.
According to another embodiment of the present invention, the mixing and stirring rotation speed of the slurry and the first acid solution is not particularly limited, and may be selected by a person skilled in the art according to actual needs, and according to an embodiment of the present invention, the mixing and stirring rotation speed of the slurry and the first acid solution may be 30 to 100r/min, and preferably 60 r/min. Therefore, the dissolving amount of precipitates such as calcium salt, iron salt and the like in the arsenic-removed sludge after slurrying can be remarkably increased, and the sludge amount is reduced.
S300: mixing the tungsten smelting wastewater with a second acid solution and a filtrate containing calcium ions and iron ions, filtering, and returning the first arsenic-removing sludge to the step S100 for slurrying
In the step, the tungsten smelting wastewater can contain at least one of sodium hydroxide, sodium chloride, sodium arsenate, sodium silicate and tungsten oxide; and mixing the filtrate containing calcium ions and iron ions obtained in the step S200 with the tungsten smelting wastewater treated by the second acid solution so as to obtain first arsenic-removing sludge and arsenic-removing filtrate. Wherein the obtained first arsenic-removing sludge can be returned to S100 for slurrying. The inventor finds that the filtrate containing calcium ions and iron ions obtained in the step S200 is used as an arsenic removal reagent to be mixed with the tungsten smelting wastewater, sodium arsenate in the tungsten smelting wastewater can be combined with the calcium ions and the iron ions in the filtrate to be converted into ferric arsenate and calcium arsenate, so that valuable elements in arsenic removal sludge can be effectively recycled, the treatment cost of the tungsten smelting wastewater can be obviously reduced, the content of arsenic elements in the tungsten smelting wastewater can be obviously reduced, arsenic removal sludge obtained by separation in the tungsten smelting wastewater treatment process is returned to the step S100 to be continuously used, and ferric salts and calcium salts in the part of arsenic removal sludge can be continuously utilized. Specifically, the arsenic content in the obtained arsenic-removing filtrate is less than 0.1 mg/L. The main chemical reaction equations involved in this step are shown below:
Na3AsO4+FeCl3＝FeAsO4↓+3NaCl (4)
2Na3AsO4+3CaCl2＝Ca3(AsO4)2↓+6NaCl (5)
FeCl3+3NaOH＝Fe(OH)3↓+3NaCl (6)
according to an embodiment of the present invention, in this step, calcium salt and iron salt may be added to a mixed solution containing the tungsten-smelting wastewater, the second acid solution, and the filtrate containing calcium ions and iron ions. The inventor finds that if all the filtrate containing calcium ions and iron ions obtained in step S200 is used as an arsenic removal reagent in the tungsten smelting wastewater in the step, the treatment amount in the treatment process is inevitably increased, and the treatment mode of adding calcium salts and iron salts into the filtrate containing calcium ions and iron ions can not only significantly reduce the raw material cost of calcium salts and iron salts, but also significantly reduce the workload and improve the economic benefit of enterprises.
According to another embodiment of the present invention, the pH of the tungsten smelting wastewater treated with the second acid solution is not particularly limited, and may be selected by a person skilled in the art according to actual needs, and according to an embodiment of the present invention, the pH of a mixed solution containing the tungsten smelting wastewater and the second acid solution may be 9.5 to 10.5. The inventor finds that the mixed liquor containing the tungsten smelting wastewater and the second acid liquor has a pH value which is too high, so that the arsenic in the tungsten smelting wastewater can not be completely removed, and the pH value which is too low can cause the waste of the second acid liquor, so that the arsenic in the tungsten smelting wastewater can not be completely removed.
According to another embodiment of the present invention, the selection of the second acid solution is not particularly limited, and may be selected by a person skilled in the art according to actual needs. Therefore, the arsenic removal rate in the tungsten smelting wastewater can be obviously improved.
According to another embodiment of the present invention, the mixing volume ratio of the tungsten smelting wastewater treated by the second acid solution to the filtrate containing calcium ions and iron ions is not particularly limited, and can be selected by those skilled in the art according to actual needs, and according to one embodiment of the present invention, the mixing volume ratio of the tungsten smelting wastewater treated by the second acid solution to the filtrate containing calcium ions and iron ions can be (15-25): 1. the inventor finds that the excessive mixing volume ratio of the tungsten smelting wastewater treated by the second acid solution and the filtrate containing calcium ions and iron ions can cause the incomplete arsenic removal of the tungsten smelting wastewater treated by the second acid solution, while the excessive mixing volume ratio can cause the low pH value of the first arsenic-removing sludge, thereby increasing the consumption of subsequent alkali liquor and simultaneously causing the waste of the filtrate containing calcium ions and iron ions.
According to another embodiment of the present invention, the mixing and stirring time of the tungsten smelting wastewater treated by the second acid solution and the filtrate containing calcium ions and iron ions is not particularly limited, and can be selected by a person skilled in the art according to actual needs, and according to an embodiment of the present invention, the mixing and stirring time of the tungsten smelting wastewater treated by the second acid solution and the filtrate containing calcium ions and iron ions can be 5 to 10 minutes. Therefore, the arsenic removal rate in the tungsten smelting wastewater can be further improved.
According to another embodiment of the present invention, the time for continuing stirring after adding the calcium salt and the iron salt is not particularly limited, and may be selected by a person skilled in the art according to actual needs, and according to a specific embodiment of the present invention, the time for continuing stirring after adding the calcium salt and the iron salt may be 5 to 10 minutes. Therefore, the arsenic removal rate in the tungsten smelting wastewater can be further improved.
According to another embodiment of the present invention, the kind of the supplementary calcium salt is not particularly limited, and may be selected by those skilled in the art according to actual needs, and according to a specific embodiment of the present invention, the supplementary calcium salt may be at least one of calcium chloride, calcium nitrate, calcium carbonate and calcium sulfate, preferably calcium chloride and calcium nitrate. The inventor finds that the calcium salt in the application has higher calcium ion concentration compared with calcium salts such as calcium carbonate and calcium sulfate, thereby being beneficial to reducing the using amount of the calcium salt and further reducing the raw material cost of the calcium salt.
According to another embodiment of the present invention, the kind of the supplementary iron salt is not particularly limited, and may be selected by one skilled in the art according to actual needs, and according to a specific embodiment of the present invention, the supplementary iron salt may be at least one of ferric chloride, ferrous chloride, ferric sulfate, and ferrous sulfate. The inventor finds that compared with other iron salts, the iron ions in the ferric chloride, the ferrous chloride, the ferric sulfate and the ferrous sulfate are higher in concentration, so that the dosage of the iron salt is favorably reduced, and the raw material cost of the iron salt is reduced.
According to another embodiment of the present invention, the mixing ratio of the added calcium salt to the tungsten smelting wastewater is not particularly limited, and can be selected by those skilled in the art according to actual needs, and according to one embodiment of the present invention, the mixing ratio of the added calcium salt to the tungsten smelting wastewater can be (0.025-0.05): 1. the inventor finds that the calcium salt is wasted due to the fact that the mixing ratio of the added calcium salt to the tungsten smelting wastewater is too high, and arsenic in the tungsten smelting wastewater is not completely removed due to the fact that the calcium salt is too low.
According to another embodiment of the present invention, the mixing ratio of the supplemented iron salt to the tungsten smelting wastewater is not particularly limited, and can be selected by those skilled in the art according to actual needs, and according to one embodiment of the present invention, the mixing ratio of the supplemented iron salt to the tungsten smelting wastewater can be (0.025-0.05): 1. the inventor finds that the ferric salt is wasted due to the fact that the mixing ratio of the supplemented ferric salt to the tungsten smelting wastewater is too high, and arsenic in the tungsten smelting wastewater is not completely removed due to the fact that the mixing ratio of the supplemented ferric salt to the tungsten smelting wastewater is too low.
S400: mixing the filter residue containing tungsten oxide with alkali liquor and filtering
In the step, the tungsten oxide-containing filter residue obtained in step S200 is mixed with an alkali solution, and then filtered to obtain a tungstate-containing filtrate and filter residue. The inventors found that by dissolving tungsten oxide in a filter residue containing tungsten oxide with alkali in an autoclave, the chemical reaction equation is: WO3+2OH-＝WO4 2-+H2And O, so that the purpose of recovering tungsten oxide is achieved, and the generated tungstate-containing filtrate can be returned to a main workshop for use. According to a specific embodiment of the invention, the inventor finds that the exchange rate of the tungsten oxide is as high as more than 85% by dissolving the filter residue containing the tungsten oxide by using alkali to recover the tungsten oxide, so that the economic benefit of enterprises is improved, the equipment is simple, the operation process is simple, and the industrial application is favorably realized.
The alkali solution is not particularly limited according to an embodiment of the present invention, and may be selected by those skilled in the art according to actual needs, and according to an embodiment of the present invention, the alkali solution may be at least one selected from the group consisting of sodium hydroxide and potassium hydroxide.
According to another embodiment of the present invention, the weight ratio of the tungsten oxide-containing filter residue to the alkali solution is not particularly limited, and may be selected by those skilled in the art according to actual needs, and according to a specific embodiment of the present invention, the weight ratio of the tungsten oxide-containing filter residue to the alkali solution may be (0.5-1.5): (1.5-2.5), preferably 1: 2. the inventors have found that a too high weight ratio of filter residue containing tungsten oxide to lye leads to an incomplete recovery of tungsten oxide in the filter residue containing tungsten oxide, whereas a too low weight ratio leads to a waste of lye.
According to another embodiment of the present invention, the mixing temperature of the tungsten oxide-containing filter residue and the alkali solution is not particularly limited, and may be selected by those skilled in the art according to actual needs, and according to a specific embodiment of the present invention, the mixing temperature of the tungsten oxide-containing filter residue and the alkali solution may be 120-150 ℃. This can significantly improve the recovery rate of tungsten oxide.
According to another embodiment of the present invention, the mixing time of the tungsten oxide-containing filter residue and the lye is not particularly limited and may be selected by those skilled in the art according to the actual requirements, and according to one embodiment of the present invention, the mixing time of the tungsten oxide-containing filter residue and the lye may be 3 to 6 hours. This can further improve the recovery rate of tungsten oxide.
According to still another embodiment of the present invention, in steps S200, S300 and S400, the filtering method is not particularly limited and may be selected by those skilled in the art according to actual needs, and according to a specific embodiment of the present invention, the filtering may independently employ at least one of vacuum suction filtering, centrifugal filtering and plate-and-frame filter pressing, respectively. Therefore, the comprehensive cyclic utilization of resources such as calcium, iron, tungsten and the like in the arsenic-removing sludge of the wastewater can be realized, the treatment process is simplified, and the industrial application is convenient to realize.
The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be limiting in any way.
The experimental procedures described in the following examples are conventional unless otherwise specified.
The starting materials described in the examples below are all commercially available.
Example 1
The method comprises the following steps:
(1) pretreatment of arsenic-removing sludge: 200kg of arsenic-removing sludge is taken, wherein the arsenic-removing sludge can contain 2 wt% of magnesium oxide, 7 wt% of silicon oxide, 70 wt% of calcium carbonate, 11 wt% of calcium hydroxide, 8 wt% of ferric hydroxide, 1.5 wt% of tungsten oxide, 0.5 wt% of arsenic oxide and the balance of other substances, and the weight is added to 10m34000kg of water was further added to the stirring vessel of (1), and the mixture was stirred for 0.5 hour to obtain a slurry.
(2) Acid dissolving stage of slurrying liquid: adding 0.25m into the stirring tank331 wt% hydrochloric acid, stirring while adding acid, stirring to react for 0.5 hr, and filtering to obtain about 4m3And (4) leaving the filtrate containing calcium ions and iron ions to be used in the step (3), and leaving 23kg of filter residue containing tungsten oxide to be used in the step (4). In the step, the dissolution rate of the arsenic-removing sludge reaches 88.5 percent, the amount of filter residue is only 11.5 percent of the amount of sludge, and WO in the filter residue3The content of 9 percent and the arsenic content of 4.5 percent.
(3) And (3) arsenic removal stage of filtrate: taking 100m at normal temperature3Adjusting the pH value of the tungsten smelting wastewater to 10.5 and then adding 4m of the arsenic obtained in the step (2) into the tungsten smelting wastewater with the arsenic concentration of 4.8mg/L3Stirring the filtrate containing calcium ions and iron ions for 5min, adding 2.5kg of ferric chloride, finally adding 30kg of alkaline calcium chloride, stirring for 5min, and then filtering to obtain arsenic-removing filtrate and arsenic-removing sludge, wherein the arsenic concentration in the arsenic-removing filtrate is 0.21mg/L, and then removing fluorine and adjusting the pH value to reach the standard and discharging; returning the arsenic-removing sludge to the step (1) for continuous treatment, wherein the removal rate of arsenic in the tungsten smelting wastewater reaches 95.6%.
(4) Alkali leaching and tungsten recovery: adding 23kg of tungsten oxide-containing filter residue generated in the step (2) into a 100L closed reaction kettle, adding 23kg of water, stirring to form slurry, adding 2.85kg of sodium hydroxide, heating to 140 ℃, stirring for reaction for 3 hours, cooling to 50 ℃, and performing plate-and-frame filtration to obtain a filtrate which is a sodium tungstate solution and can be returned to the main flow for use; the obtained filter residue WO3The content of the tungsten slag is 1.3 percent, the content of the arsenic is 5.1 percent, the filter residue and the tungsten slag are recycled and treated by qualified units, and WO in the filter residue is treated in the stage3Is returned toThe yield reaches 85.6 percent.
Example 2
The method comprises the following steps:
(1) pretreatment of arsenic-removing sludge: 200kg of arsenic-removing sludge is taken, wherein the arsenic-removing sludge can contain 2 wt% of magnesium oxide, 7 wt% of silicon oxide, 70 wt% of calcium carbonate, 11 wt% of calcium hydroxide, 8 wt% of ferric hydroxide, 1.5 wt% of tungsten oxide, 0.5 wt% of arsenic oxide and the balance of other substances, and the weight is added to 10m35000kg of water was further added to the stirring vessel of (1), and the mixture was stirred for 0.5 hour to obtain a slurry.
(2) Acid dissolving stage of slurrying liquid: adding 0.3m into the stirring tank3Adding 31% hydrochloric acid while stirring, stirring for reaction for 0.5 hr, and filtering to obtain 5m solution containing calcium ion and iron ion3And (4) reserving the filtrate in the step (3) for use, and reserving the obtained 15kg of filter residue containing tungsten oxide in the step (4) for use. In the step, the dissolution rate of the arsenic-removing sludge reaches 92.5 percent, the amount of filter residue accounts for 7.5 percent of the amount of sludge, and WO in the filter residue3The content of arsenic was 13.5% and 4.3%.
(3) And (3) arsenic removal stage of filtrate: taking 100m at normal temperature3Adjusting the pH value of the tungsten smelting wastewater to 10.0 and then adding 5m of the arsenic obtained in the step (2) into the tungsten smelting wastewater with the arsenic concentration of 5.4mg/L3Stirring the filtrate containing calcium ions and iron ions for 5min, adding 2.0kg of ferric chloride, finally adding 24kg of alkaline calcium chloride, stirring for 5min, and filtering to obtain arsenic-removed filtrate and arsenic-removed sludge. Wherein, the arsenic concentration in the arsenic-removing filtrate is 0.08mg/L, and the arsenic can be discharged after reaching the standard after defluorination and pH adjustment; returning the arsenic-removing sludge to the step (1) for continuous treatment, wherein the removal rate of the arsenic in the tungsten smelting wastewater reaches 98.5%.
(4) Alkali leaching and tungsten recovery: adding 15kg of tungsten oxide-containing filter residue generated in the step (2) into a 100L closed reaction kettle, adding 15kg of water, stirring to form slurry, adding 3.5kg of sodium hydroxide, heating to 160 ℃, stirring for reacting for 4 hours, cooling to 50 ℃, and performing plate-and-frame filtration to obtain a filtrate which is a sodium tungstate solution and can be returned to the main flow for use; the obtained filter residue WO30.9 percent of arsenic and 5.7 percent of tungsten slagQualified unit recovery treatment, in this stage, WO in filter residue3The recovery rate of the product reaches 93.3 percent.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (23)
1. A method for treating tungsten smelting wastewater by using arsenic-removing sludge, wherein the arsenic-removing sludge contains calcium carbonate, calcium hydroxide, iron hydroxide and tungsten oxide, and is characterized by comprising the following steps:
(1) mixing the arsenic-removing sludge with water so as to obtain slurry;
(2) mixing and dissolving the slurry liquid and a first acid liquid, and filtering to obtain a filtrate containing calcium ions and iron ions and a filter residue containing tungsten oxide;
(3) mixing tungsten smelting wastewater with a second acid solution and the filtrate containing calcium ions and iron ions, filtering to obtain first arsenic-removing sludge and arsenic-removing filtrate, and returning the first arsenic-removing sludge to the step (1) for slurrying, wherein the tungsten smelting wastewater contains sodium hydroxide, sodium chloride, sodium arsenate, sodium silicate and tungsten oxide;
(4) mixing the filter residue containing tungsten oxide with alkali liquor, filtering to obtain filtrate and filter residue containing tungstate,
wherein in the step (3), the pH value of the mixed solution containing the tungsten smelting wastewater and the second acid solution is 9.5-10.5.
2. The method according to claim 1, wherein in the step (1), the mixing mass ratio of the water to the arsenic removal sludge is (20-25): 1.
3. the method according to claim 1, wherein in the step (1), the arsenic-removing sludge is mixed with the water and stirred for 0.3 to 1 hour.
4. The method according to claim 3, wherein in step (1), the arsenic-removing sludge is mixed with the water under stirring for 0.5 hours.
5. The method according to claim 1, wherein in the step (2), the first acid solution is at least one selected from hydrochloric acid and nitric acid.
6. The method according to claim 1, wherein in the step (2), the mass concentration of the first acid solution is 20-40%.
7. The method according to claim 6, wherein in the step (2), the mass concentration of the first acid solution is 31%.
8. The method according to claim 5, wherein in the step (2), the mixing volume ratio of the slurry liquid to the first acid liquid is (15-25): 1.
9. the method according to claim 5, wherein in the step (2), the slurry and the first acid solution are mixed and stirred for 0.5 to 1.5 hours.
10. The method according to claim 5, wherein in the step (2), the mixing and stirring speed of the slurry and the first acid liquid is 30-100 r/min.
11. The method according to claim 5, wherein in the step (2), the mixing and stirring speed of the slurry and the first acid liquid is 60 r/min.
12. The method of claim 1, wherein step (3) further comprises: adding calcium salt and iron salt into the mixed solution of the tungsten smelting wastewater, the second acid solution and the filtrate containing calcium ions and iron ions.
13. The method according to claim 12, wherein the second acid solution is at least one selected from hydrochloric acid and nitric acid.
14. The method according to claim 12, wherein the mixing volume ratio of the tungsten smelting wastewater to the filtrate containing calcium ions and iron ions is (15-25): 1.
15. the method according to claim 12, wherein the tungsten smelting wastewater is mixed with the second acid solution and the filtrate containing calcium ions and iron ions for 5-10 minutes.
16. The method of claim 14, wherein the stirring is continued for 5 to 10 minutes after the calcium salt and the iron salt are added.
17. The method of claim 14, wherein the calcium salt is at least one of calcium chloride, calcium nitrate, calcium carbonate, and calcium sulfate, and the iron salt is at least one of ferric chloride, ferrous chloride, ferric sulfate, and ferrous sulfate.
18. The method of claim 14, wherein the calcium salts are calcium chloride and calcium nitrate.
19. The method according to claim 1, wherein in the step (4), the alkali solution is at least one selected from the group consisting of sodium hydroxide and potassium hydroxide.
20. The method according to claim 1, wherein the weight ratio of the tungsten oxide-containing filter residue to the alkali liquor is (0.5-1.5): (1.5-2.5).
21. The method according to claim 20, wherein the weight ratio of the tungsten oxide containing filter residue to the lye is 1: 2.
22. the method according to claim 1, wherein the mixing temperature of the tungsten oxide-containing filter residue and the alkali liquor is 120-150 ℃ and the mixing time is 3-6 hours.
23. The method according to claim 1, wherein in the steps (2) (3) (4), the filtration is independently at least one of vacuum suction filtration, centrifugal filtration and plate-and-frame filter-pressing.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0347240A2 (en) * | 1988-06-16 | 1989-12-20 | Inc. Industrial Waste Management | Method for recycle and use of contaminated soil and sludge |
| US5820966A (en) * | 1997-12-09 | 1998-10-13 | Inco Limited | Removal of arsenic from iron arsenic and sulfur dioxide containing solutions |
| CN101171348A (en) * | 2005-05-03 | 2008-04-30 | 奥图泰有限公司 | Method for the recovery of valuable metals and arsenic from a solution |
| CN102107981A (en) * | 2009-12-23 | 2011-06-29 | 湖南布鲁斯凯环保科技发展有限公司 | High-efficiency method for treating arsenic-containing wastewater |
| CN104058515A (en) * | 2014-05-08 | 2014-09-24 | 昆明有色冶金设计研究院股份公司 | Acid wastewater treatment system and method |
-
2016
- 2016-12-19 CN CN201611179880.9A patent/CN106746402B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0347240A2 (en) * | 1988-06-16 | 1989-12-20 | Inc. Industrial Waste Management | Method for recycle and use of contaminated soil and sludge |
| US5820966A (en) * | 1997-12-09 | 1998-10-13 | Inco Limited | Removal of arsenic from iron arsenic and sulfur dioxide containing solutions |
| CN101171348A (en) * | 2005-05-03 | 2008-04-30 | 奥图泰有限公司 | Method for the recovery of valuable metals and arsenic from a solution |
| CN102107981A (en) * | 2009-12-23 | 2011-06-29 | 湖南布鲁斯凯环保科技发展有限公司 | High-efficiency method for treating arsenic-containing wastewater |
| CN104058515A (en) * | 2014-05-08 | 2014-09-24 | 昆明有色冶金设计研究院股份公司 | Acid wastewater treatment system and method |
Non-Patent Citations (1)
| Title |
|---|
| 铁砷共沉淀中的硫酸钙对砷固定作用;李小亮等;《生态学杂质》;20141031;第33卷(第10期);第2803-2809页 * |
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