CN115477315B - Method for preparing potassium fluoride by utilizing buffer oxide etching waste liquid - Google Patents
Method for preparing potassium fluoride by utilizing buffer oxide etching waste liquid Download PDFInfo
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- 239000007788 liquid Substances 0.000 title claims abstract description 102
- NROKBHXJSPEDAR-UHFFFAOYSA-M potassium fluoride Chemical compound [F-].[K+] NROKBHXJSPEDAR-UHFFFAOYSA-M 0.000 title claims abstract description 74
- 239000002699 waste material Substances 0.000 title claims abstract description 57
- 238000005530 etching Methods 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 39
- 239000011698 potassium fluoride Substances 0.000 title claims abstract description 37
- 235000003270 potassium fluoride Nutrition 0.000 title claims abstract description 37
- 239000000463 material Substances 0.000 claims abstract description 107
- 238000001694 spray drying Methods 0.000 claims abstract description 26
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 18
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 18
- 239000011591 potassium Substances 0.000 claims abstract description 18
- 238000002156 mixing Methods 0.000 claims abstract description 11
- 239000011259 mixed solution Substances 0.000 claims abstract description 9
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 claims description 36
- 239000000243 solution Substances 0.000 claims description 16
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 13
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 9
- 235000015497 potassium bicarbonate Nutrition 0.000 claims description 5
- 239000011736 potassium bicarbonate Substances 0.000 claims description 5
- 229910000028 potassium bicarbonate Inorganic materials 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 abstract description 7
- 238000011084 recovery Methods 0.000 abstract description 4
- 238000002360 preparation method Methods 0.000 abstract description 3
- 239000000047 product Substances 0.000 description 20
- 230000001276 controlling effect Effects 0.000 description 15
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 9
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 9
- 239000002253 acid Substances 0.000 description 6
- 230000009615 deamination Effects 0.000 description 5
- 238000006481 deamination reaction Methods 0.000 description 5
- 239000000706 filtrate Substances 0.000 description 5
- 238000001914 filtration Methods 0.000 description 5
- -1 hydrogen ions Chemical class 0.000 description 5
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 4
- 229910021529 ammonia Inorganic materials 0.000 description 4
- 229910017604 nitric acid Inorganic materials 0.000 description 4
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 4
- 239000013049 sediment Substances 0.000 description 4
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 3
- 235000011941 Tilia x europaea Nutrition 0.000 description 3
- 238000004821 distillation Methods 0.000 description 3
- 229940104869 fluorosilicate Drugs 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 239000004571 lime Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 150000001339 alkali metal compounds Chemical class 0.000 description 2
- 150000001341 alkaline earth metal compounds Chemical class 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 2
- 229910001634 calcium fluoride Inorganic materials 0.000 description 2
- 159000000007 calcium salts Chemical class 0.000 description 2
- 238000010979 pH adjustment Methods 0.000 description 2
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 2
- 229910000027 potassium carbonate Inorganic materials 0.000 description 2
- 235000011181 potassium carbonates Nutrition 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 239000010802 sludge Substances 0.000 description 2
- 235000010344 sodium nitrate Nutrition 0.000 description 2
- 239000004317 sodium nitrate Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910000885 Dual-phase steel Inorganic materials 0.000 description 1
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 150000004673 fluoride salts Chemical class 0.000 description 1
- 229910052731 fluorine Inorganic materials 0.000 description 1
- 239000011737 fluorine Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229920005591 polysilicon Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D3/00—Halides of sodium, potassium or alkali metals in general
- C01D3/02—Fluorides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C1/00—Ammonia; Compounds thereof
- C01C1/24—Sulfates of ammonium
- C01C1/242—Preparation from ammonia and sulfuric acid or sulfur trioxide
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
- C01P2006/82—Compositional purity water content
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Removal Of Specific Substances (AREA)
- Heat Treatment Of Water, Waste Water Or Sewage (AREA)
Abstract
The invention relates to a method for preparing potassium fluoride by utilizing buffered oxide etching waste liquid, which comprises the following steps: (1) Adjusting the pH value of the first buffer oxide etching waste liquid to 9-12 by adopting a potassium-containing material to obtain an adjusting liquid; (2) Carrying out stripping treatment on the adjustment liquid obtained in the step (1) to obtain stripping liquid, and then mixing the stripping liquid with the second buffer oxide etching waste liquid to obtain a mixed liquid with the pH value of 7-8; (3) And (3) concentrating and spray-drying the mixed solution obtained in the step (2) in sequence to obtain a potassium fluoride product. According to the method provided by the invention, the pH value of the material is controlled in a gradient manner by adopting a specific technological process, and the waste liquid is utilized for multiple times to participate in the recovery process of the waste liquid, so that the preparation of a high-quality potassium fluoride product is realized, the purity of the obtained potassium fluoride product is more than or equal to 98.25%, the water content is less than or equal to 1.03%, and the mass percentage of the potassium fluoride product is calculated.
Description
Technical Field
The invention relates to the technical field of waste liquid treatment in the semiconductor industry, in particular to a method for preparing potassium fluoride by utilizing buffered oxide etching waste liquid.
Background
Currently, a buffer oxide etching solution is generally used in etching in the semiconductor industry, and is formed by mixing hydrofluoric acid (49%) with water or ammonium fluoride with water. Typically, there are different composition ratios, for example, 6:1 buffered oxide etching, i.e., a mixture of components representing 49% aqueous hydrogen fluoride to 40% aqueous ammonium fluoride=1:6 (volume ratio). The etching rate is about 10nm per second. Among the buffered oxide etchants, hydrofluoric acid is the main etchant, and ammonium fluoride is used as a buffer. Immobilization by ammonium fluoride [ H ] + The concentration is kept at a certain etching rate. After the buffer oxide etching solution is used for a certain time, the etching speed can not reach the requirement due to the consumption of hydrogen ions.
The current treatment method for the etching waste liquid is to add lime or slaked lime to react into calcium fluoride and ammonia water, the ammonia water can be recovered by a conditional disposal unit, and the calcium fluoride becomes sludge to be used for harmless landfill. The invention discloses a mixed acid treatment method for etching waste liquid, which relates to mixed acid recovery treatment, and comprises the following steps: fluoride, sulfate, fluorosilicate, and nitrate ions, the method comprising a first protocol and a second protocol, the first protocol comprising: mixing acid of etching waste liquid with lime to react so as to prepare calcium salt from fluoride ions, sulfate ions and fluosilicate ions, and reacting nitrate ions with sodium salt to prepare sodium nitrate and crystallizing and removing the sodium nitrate; the second scheme comprises the following steps: the mixed acid of the etching waste liquid reacts with lime to prepare calcium salt from fluoride ion, sulfate ion, fluosilicate ion and nitrate ion. Valuable hydrofluoric acid, nitric acid, sulfuric acid and fluosilicic acid in the waste liquid can be recovered in the form of metal salt.
CN104973580a discloses a treatment method for recycling and regenerating etching waste liquid of polysilicon texturing, which comprises the following steps: (a) Adding an alkali metal compound into the etching waste liquid under the stirring condition to react until no sediment is generated, and filtering to obtain a first sediment and a first filtrate; (b) Adding alkaline earth metal compounds into the first filtrate under the stirring condition to react until no sediment is generated, and filtering to obtain a second sediment and a second filtrate; (c) And distilling the second filtrate to obtain a nitric acid solution. According to the treatment method for recycling the polycrystalline silicon etching waste liquid, alkali metal compounds are added into the etching waste liquid to react until precipitation is not generated, alkaline earth metal compounds are added into filtrate after filtration, and then filtration is carried out, and finally nitric acid solution is obtained through distillation, so that fluorosilicate ions and fluoride ions in the waste liquid can be removed, fluorosilicate, fluoride salt and nitric acid solution which can be recycled are obtained, the environment can be protected, and the cost is saved.
However, the treatment method has the problems of high cost, large pollution and high sludge disposal cost, and meanwhile, when the waste liquid is comprehensively utilized to prepare the potassium fluoride, distillation, concentration and crystallization are generally adopted, and then centrifugation is carried out, so that the prepared product has high water content and is easy to agglomerate, and the product quality is influenced.
Disclosure of Invention
In view of the problems in the prior art, the invention aims to provide a method for preparing potassium fluoride by utilizing the buffer oxide etching waste liquid, which realizes the comprehensive utilization of the buffer oxide etching waste liquid and effectively recovers ammonia and fluorine in materials.
To achieve the purpose, the invention adopts the following technical scheme:
the invention provides a method for preparing potassium fluoride by utilizing buffered oxide etching waste liquid, which comprises the following steps:
(1) Adjusting the pH value of the first buffer oxide etching waste liquid to 9-12 by adopting a potassium-containing material to obtain an adjusting liquid;
(2) Carrying out stripping treatment on the adjustment liquid obtained in the step (1) to obtain stripping liquid, and then mixing the stripping liquid with the second buffer oxide etching waste liquid to obtain a mixed liquid with the pH value of 7-8;
(3) And (3) concentrating and spray-drying the mixed solution obtained in the step (2) in sequence to obtain a potassium fluoride product.
According to the method provided by the invention, the pH value of the material is controlled in a gradient manner by adopting a specific technological process, and the waste liquid is utilized for multiple times to participate in the recovery process of the waste liquid, so that the preparation of a high-quality potassium fluoride product is realized, the purity of the obtained potassium fluoride product is more than or equal to 98.25%, the water content is less than or equal to 1.03%, and the mass percentage of the potassium fluoride product is calculated.
In the present invention, the pH of the adjustment liquid is 9 to 12, and may be, for example, 9, 10, 11 or 12, etc., but not limited to the values recited, and other values not recited in the range are equally applicable.
In the present invention, the pH of the mixture is 7 to 8, and for example, 7, 7.2, 7.4, 7.6, 7.8 or 8 may be used, but the present invention is not limited to the above-mentioned values, and other values not mentioned in the above range are equally applicable.
In the invention, the sources of the first buffer oxide etching waste liquid and the second buffer oxide etching waste liquid can be the same, or the sources of the buffer oxide etching waste liquids can be different.
As a preferred embodiment of the present invention, the potassium-containing material in step (1) comprises 1 or a combination of at least 2 of potassium hydroxide solution, potassium carbonate solution or potassium bicarbonate solution.
In the invention, the potassium-containing material can also be potassium hydroxide solid, potassium carbonate solid or potassium bicarbonate solid, etc.
As a preferred embodiment of the present invention, the stripping treatment in step (2) is performed in a PP stripping tower.
As a preferable technical scheme of the invention, when the ammonia nitrogen concentration of the material in the stripping treatment in the step (2) is more than 5g/L, the pH value of the material is controlled to be more than 10, for example, the ammonia nitrogen concentration of the material is 6g/L, 8g/L, 10g/L, 15g/L or 20g/L, and the pH value of the material is controlled to be 10.5, 11 or 12, and the like, but the method is not limited to the listed values, and other non-listed values in the range are applicable.
As a preferable technical scheme of the invention, when the ammonia nitrogen concentration of the material in the stripping treatment in the step (2) is 1-5g/L, the pH value of the material is controlled to be 9-10, for example, when the ammonia nitrogen concentration of the material is 1g/L, 2g/L, 3g/L, 4g/L or 5g/L, the pH value of the material is controlled to be 9, 9.2, 9.4, 9.6, 9.8 or 10, etc., but the method is not limited to the listed values, and other values not listed in the range are equally applicable.
As a preferable technical scheme of the invention, when the ammonia nitrogen concentration of the material in the stripping treatment in the step (2) is less than 1g/L, the pH value of the material is controlled to be 8-9, for example, when the ammonia nitrogen concentration of the material is 0.1g/L, 0.2g/L, 0.4g/L, 0.6g/L or 0.8g/L, the pH value of the material is controlled to be 8, 8.2, 8.4, 8.6, 8.8 or 9, and the like, but the method is not limited to the listed values, and other non-listed values in the range are applicable.
As a preferred embodiment of the present invention, the end point of the stripping treatment in the step (2) is that the ammonia nitrogen concentration of the material is less than 50ppm, and for example, 48ppm, 46ppm, 44ppm, 42ppm, 40ppm, 35ppm, 30ppm, 25ppm, 20ppm, 15ppm or 10ppm, etc., but not limited to the recited values, and other values not recited in the range are equally applicable.
As a preferred embodiment of the present invention, the volume of the concentrated material at the end of the concentration in the step (3) is 0.25 to 0.3 times the volume of the material before concentration, for example, 0.25 times, 0.26 times, 0.27 times, 0.28 times, 0.29 times or 0.3 times, etc., but not limited to the recited values, and other non-recited values within this range are equally applicable.
In a preferred embodiment of the present invention, the spray-drying in the step (3) is carried out at a temperature of 230 to 300. For example, 230. DegreeLess 235. DegreeLess 240. DegreeLess 245. DegreeLess 250. DegreeLess 260. DegreeLess 265. DegreeLess 270. DegreeLess 275. DegreeLess 280. DegreeLess 285. DegreeLess 290. DegreeLess 295. DegreeLess 300. DegreeLess, however, the present invention is not limited to the above-mentioned values, and other values not mentioned in the above-mentioned range are equally applicable.
Preferably, the flow rate of the material in the spray drying in the step (3) is 65-75L/h, for example, 65L/h, 66L/h, 67L/h, 68L/h, 69L/h, 70L/h, 71L/h, 72L/h, 73L/h, 74L/h or 75L/h, etc., but not limited to the recited values, and other non-recited values in the range are equally applicable.
As a preferred technical scheme of the invention, the method comprises the following steps:
(1) Adjusting the pH value of the first buffer oxide etching waste liquid to 9-12 by adopting a potassium-containing material to obtain an adjusting liquid;
(2) Carrying out stripping treatment on the adjustment liquid obtained in the step (1) to obtain stripping liquid, and then mixing the stripping liquid with the second buffer oxide etching waste liquid to obtain a mixed liquid with the pH value of 7-8;
(3) Concentrating and spray drying the mixed solution obtained in the step (2) in sequence to obtain a potassium fluoride product;
the potassium-containing material of step (1) comprises 1 or a combination of at least 2 of potassium hydroxide solution, potassium carbonate solution, or potassium bicarbonate solution;
the stripping treatment in the step (2) is carried out in a PP stripping tower; when the ammonia nitrogen concentration of the material in the stripping treatment is more than 5g/L, controlling the pH value of the material to be more than 10; when the ammonia nitrogen concentration of the material in the stripping treatment is 1-5g/L, controlling the pH value of the material to be 9-10; when the ammonia nitrogen concentration of the material in the stripping treatment is less than 1g/L, controlling the pH value of the material to be 8-9; the end point of the stripping treatment is that the ammonia nitrogen concentration of the material is less than 50ppm;
the volume of the concentrated material at the concentration end point in the step (3) is 0.25-0.3 times of the volume of the material before concentration; the operation temperature of the spray drying is 230-300 ℃; the flow rate of the material in the spray drying is 65-75L/h.
In the invention, the stripping treatment is to blow ammonia out of the regulating solution, and then the ammonia is absorbed by adopting an acid solution, so that the high-efficiency utilization of ammonia in the waste material is realized.
In the invention, 2205 dual-phase steel distillation facilities can be adopted for concentration operation in the concentration.
Compared with the prior art, the invention has the following beneficial effects:
(1) The method of the invention utilizes the buffer oxide etching waste liquid, only conventional equipment is used, the equipment investment cost is reduced, the treatment cost is reduced, the process is simple, the operation is easy, and the skill requirement on workers is reduced.
(2) In the deamination process, the ammonia nitrogen content in the solution is detected, and the amount of the added potassium hydroxide is calculated, so that the pH value of the solution after deamination is close to 7-8; the pH adjustment step after deamination is performed by using the original buffer oxide etching waste liquid, so that hydrofluoric acid is avoided, and the improvement of the indexes of potassium fluoride products is realized.
(3) The invention adopts pH adjustment, filtration, deamination, concentration and spray drying. After the treatment of the steps, each component of the buffer oxide etching waste liquid is fully and reasonably recycled, and the prepared potassium fluoride finished product is white powder and is not easy to crystallize and agglomerate; ammonia gas generated by deamination is absorbed by an acid solution to prepare ammonium sulfate; the cost of the agent for directly neutralizing the waste liquid and the solid landfill cost are reduced, the problems existing in the treatment process of the buffer oxide etching waste liquid are overcome, the resources are recycled to the greatest extent, the pollutants discharged to the environment are minimized, and the comprehensive treatment cost is reduced.
Detailed Description
For a better illustration of the present invention, which is convenient for understanding the technical solution of the present invention, exemplary but non-limiting examples of the present invention are as follows:
example 1
The embodiment provides a method for preparing potassium fluoride by using buffer oxide etching waste liquid, which comprises the following steps:
(1) Adjusting the pH value of the first buffer oxide etching waste liquid to 10 by adopting a potassium-containing material to obtain an adjusting liquid;
(2) Carrying out stripping treatment on the adjustment liquid obtained in the step (1) to obtain stripping liquid, and then mixing the stripping liquid with the second buffer oxide etching waste liquid to obtain a mixed liquid with the pH value of 8;
(3) Concentrating and spray drying the mixed solution obtained in the step (2) in sequence to obtain a potassium fluoride product;
the potassium-containing material in the step (1) is potassium hydroxide solution;
the stripping treatment in the step (2) is carried out in a PP stripping tower; when the ammonia nitrogen concentration of the material in the stripping treatment is more than 5g/L, controlling the pH value of the material to be 10.5; when the ammonia nitrogen concentration of the material in the stripping treatment is 1-5g/L, controlling the pH value of the material to be 9.5; when the ammonia nitrogen concentration of the material in the stripping treatment is less than 1g/L, controlling the pH value of the material to be 8.5; the end point of the stripping treatment is that the ammonia nitrogen concentration of the material is 40ppm;
the volume of the concentrated material at the concentration end point in the step (3) is 0.3 times of the volume of the material before concentration; the operation temperature of the spray drying is 270 ℃; the flow rate of the material in the spray drying is 70L/h.
The indexes of the obtained potassium fluoride product are shown in Table 1 in detail.
Example 2
The embodiment provides a method for preparing potassium fluoride by using buffer oxide etching waste liquid, which comprises the following steps:
(1) Adjusting the pH value of the first buffer oxide etching waste liquid to 11 by adopting a potassium-containing material to obtain an adjusting liquid;
(2) Carrying out stripping treatment on the adjustment liquid obtained in the step (1) to obtain stripping liquid, and then mixing the stripping liquid with the second buffer oxide etching waste liquid to obtain a mixed liquid with the pH value of 7;
(3) Concentrating and spray drying the mixed solution obtained in the step (2) in sequence to obtain a potassium fluoride product;
the potassium-containing material in the step (1) is potassium carbonate;
the stripping treatment in the step (2) is carried out in a PP stripping tower; when the ammonia nitrogen concentration of the material in the stripping treatment is more than 5g/L, controlling the pH value of the material to be 12; when the ammonia nitrogen concentration of the material in the stripping treatment is 1-5g/L, controlling the pH value of the material to be 9; when the ammonia nitrogen concentration of the material in the stripping treatment is less than 1g/L, controlling the pH value of the material to be 8; the end point of the stripping treatment is that the ammonia nitrogen concentration of the material is 30ppm;
the volume of the concentrated material at the concentration end point in the step (3) is 0.25 times of the volume of the material before concentration; the operation temperature of the spray drying is 300 ℃; the flow rate of the material in the spray drying is 65L/h.
The indexes of the obtained potassium fluoride product are shown in Table 1 in detail.
Example 3
The embodiment provides a method for preparing potassium fluoride by using buffer oxide etching waste liquid, which comprises the following steps:
(1) Adjusting the pH value of the first buffer oxide etching waste liquid to 9 by adopting a potassium-containing material to obtain an adjusting liquid;
(2) Carrying out stripping treatment on the adjustment liquid obtained in the step (1) to obtain stripping liquid, and then mixing the stripping liquid with the second buffer oxide etching waste liquid to obtain a mixed liquid with the pH value of 7.6;
(3) Concentrating and spray drying the mixed solution obtained in the step (2) in sequence to obtain a potassium fluoride product;
the potassium-containing material in the step (1) is potassium hydroxide solution;
the stripping treatment in the step (2) is carried out in a PP stripping tower; when the ammonia nitrogen concentration of the material in the stripping treatment is more than 5g/L, controlling the pH value of the material to be more than 11.5; when the ammonia nitrogen concentration of the material in the stripping treatment is 1-5g/L, controlling the pH value of the material to be 9.8; when the ammonia nitrogen concentration of the material in the stripping treatment is less than 1g/L, controlling the pH value of the material to be 9; the end point of the stripping treatment is that the ammonia nitrogen concentration of the material is 10ppm;
the volume of the concentrated material at the concentration end point in the step (3) is 0.27 times of the volume of the material before concentration; the operation temperature of the spray drying is 230 ℃; the flow rate of the material in the spray drying is 68L/h.
The indexes of the obtained potassium fluoride product are shown in Table 1 in detail.
Example 4
The embodiment provides a method for preparing potassium fluoride by using buffer oxide etching waste liquid, which comprises the following steps:
(1) Adjusting the pH value of the first buffer oxide etching waste liquid to 12 by adopting a potassium-containing material to obtain an adjusting liquid;
(2) Carrying out stripping treatment on the adjustment liquid obtained in the step (1) to obtain stripping liquid, and then mixing the stripping liquid with the second buffer oxide etching waste liquid to obtain a mixed liquid with the pH value of 7-8;
(3) Concentrating and spray drying the mixed solution obtained in the step (2) in sequence to obtain a potassium fluoride product;
the potassium-containing material in the step (1) is potassium hydroxide solution;
the stripping treatment in the step (2) is carried out in a PP stripping tower; when the ammonia nitrogen concentration of the material in the stripping treatment is more than 5g/L, controlling the pH value of the material to be more than 11; when the ammonia nitrogen concentration of the material in the stripping treatment is 1-5g/L, controlling the pH value of the material to be 10; when the ammonia nitrogen concentration of the material in the stripping treatment is less than 1g/L, controlling the pH value of the material to be 8.3; the end point of the stripping treatment is that the ammonia nitrogen concentration of the material is 20ppm;
the volume of the concentrated material at the concentration end point in the step (3) is 0.28 times of the volume of the material before concentration; the operation temperature of the spray drying is 250 ℃; the flow rate of the material in the spray drying is 75L/h.
The indexes of the obtained potassium fluoride product are shown in Table 1 in detail.
TABLE 1
| Potassium fluoride content/% | Water content/% | Other impurities/% | |
| Example 1 | 98.88 | 0.44 | 0.68 |
| Example 2 | 98.68 | 0.68 | 0.64 |
| Example 3 | 98.25 | 1.03 | 0.72 |
| Example 4 | 98.45 | 0.94 | 0.61 |
As can be seen from the results of the above examples, the method provided by the invention realizes the preparation of high-quality potassium fluoride products by adopting a specific process and utilizing waste liquid for multiple times to participate in the recovery process of the waste liquid, wherein the purity of the obtained potassium fluoride products is more than or equal to 98.25%, the water content is less than or equal to 1.03%, and the obtained potassium fluoride products are all calculated according to the mass percentage.
It is stated that the detailed structural features of the present invention are described by the above embodiments, but the present invention is not limited to the above detailed structural features, i.e., it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be apparent to those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, addition of auxiliary components, selection of specific modes, etc., are within the scope of the present invention and the scope of the disclosure.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications belong to the protection scope of the present invention.
In addition, the specific features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various possible combinations are not described further.
Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.
Claims (8)
1. The method for preparing potassium fluoride by using the buffer oxide etching waste liquid is characterized by comprising the following steps:
(1) Adjusting the pH value of the first buffer oxide etching waste liquid to 9-12 by adopting a potassium-containing material to obtain an adjusting liquid;
(2) Carrying out stripping treatment on the adjustment liquid obtained in the step (1) to obtain stripping liquid, and then mixing the stripping liquid with the second buffer oxide etching waste liquid to obtain a mixed liquid with the pH value of 7-8;
(3) Concentrating and spray drying the mixed solution obtained in the step (2) in sequence to obtain a potassium fluoride product;
wherein, when the ammonia nitrogen concentration of the material in the stripping treatment in the step (2) is more than 5g/L, the pH value of the material is controlled to be more than 10;
when the ammonia nitrogen concentration of the material in the stripping treatment in the step (2) is 1-5g/L, controlling the pH value of the material to be 9-10;
and (3) controlling the pH value of the material to be 8-9 when the ammonia nitrogen concentration of the material in the stripping treatment in the step (2) is less than 1 g/L.
2. The method of claim 1, wherein the potassium-containing material of step (1) comprises 1 or a combination of at least 2 of potassium hydroxide solution, potassium carbonate solution, or potassium bicarbonate solution.
3. The process of claim 1 wherein the stripping treatment of step (2) is carried out in a PP stripping column.
4. The method of claim 1, wherein the stripping treatment in step (2) is terminated at a material ammonia nitrogen concentration of < 50ppm.
5. The method of claim 1, wherein the volume of the concentrated material at the end of the concentration in step (3) is 0.25 to 0.3 times the volume of the material before concentration.
6. The method of claim 1, wherein the spray drying of step (3) is performed at a temperature of 230 ℃ to 300 ℃.
7. The method of claim 1, wherein the flow rate of the material in the spray drying of step (3) is 65-75L/h.
8. The method according to claim 1, characterized in that the method comprises the steps of:
(1) Adjusting the pH value of the first buffer oxide etching waste liquid to 9-12 by adopting a potassium-containing material to obtain an adjusting liquid;
(2) Carrying out stripping treatment on the adjustment liquid obtained in the step (1) to obtain stripping liquid, and then mixing the stripping liquid with the second buffer oxide etching waste liquid to obtain a mixed liquid with the pH value of 7-8;
(3) Concentrating and spray drying the mixed solution obtained in the step (2) in sequence to obtain a potassium fluoride product;
the potassium-containing material of step (1) comprises 1 or a combination of at least 2 of potassium hydroxide solution, potassium carbonate solution, or potassium bicarbonate solution;
the stripping treatment in the step (2) is carried out in a PP stripping tower; when the ammonia nitrogen concentration of the material in the stripping treatment is more than 5g/L, controlling the pH value of the material to be more than 10; when the ammonia nitrogen concentration of the material in the stripping treatment is 1-5g/L, controlling the pH value of the material to be 9-10; when the ammonia nitrogen concentration of the material in the stripping treatment is less than 1g/L, controlling the pH value of the material to be 8-9; the end point of the stripping treatment is that the ammonia nitrogen concentration of the material is less than 50ppm;
the volume of the concentrated material at the concentration end point in the step (3) is 0.25-0.3 times of the volume of the material before concentration; the operation temperature of the spray drying is 230-300 ℃; the flow rate of the material in the spray drying is 65-75L/h.
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| US4713231A (en) * | 1986-07-21 | 1987-12-15 | The Dow Chemical Company | Process for the recovery of ammonia and fluoride values from ammonium fluoride solutions |
| CN103818933A (en) * | 2014-02-25 | 2014-05-28 | 浙江大洋生物科技集团股份有限公司 | Method for production of high-purity potassium fluoride by using hydrofluoric acid residual liquid |
| CN106336039A (en) * | 2016-09-26 | 2017-01-18 | 大连东泰产业废弃物处理有限公司 | Method of non-noxious treatment of scrapped silicon dioxide etching solution |
| CN215288251U (en) * | 2020-11-03 | 2021-12-24 | 湖南高安新材料有限公司 | Device for processing buffer oxide etching liquid |
| CN114291830A (en) * | 2021-03-17 | 2022-04-08 | 河南省氟基新材料科技有限公司 | Comprehensive utilization method of etching waste liquid |
| CN114477558A (en) * | 2022-03-03 | 2022-05-13 | 无锡中天固废处置有限公司 | Ammonia-removing treatment method for ammonia nitrogen wastewater |
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Patent Citations (6)
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| US4713231A (en) * | 1986-07-21 | 1987-12-15 | The Dow Chemical Company | Process for the recovery of ammonia and fluoride values from ammonium fluoride solutions |
| CN103818933A (en) * | 2014-02-25 | 2014-05-28 | 浙江大洋生物科技集团股份有限公司 | Method for production of high-purity potassium fluoride by using hydrofluoric acid residual liquid |
| CN106336039A (en) * | 2016-09-26 | 2017-01-18 | 大连东泰产业废弃物处理有限公司 | Method of non-noxious treatment of scrapped silicon dioxide etching solution |
| CN215288251U (en) * | 2020-11-03 | 2021-12-24 | 湖南高安新材料有限公司 | Device for processing buffer oxide etching liquid |
| CN114291830A (en) * | 2021-03-17 | 2022-04-08 | 河南省氟基新材料科技有限公司 | Comprehensive utilization method of etching waste liquid |
| CN114477558A (en) * | 2022-03-03 | 2022-05-13 | 无锡中天固废处置有限公司 | Ammonia-removing treatment method for ammonia nitrogen wastewater |
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