CN117771905A - Preparation method and equipment of high-purity sodium hypophosphite - Google Patents
Preparation method and equipment of high-purity sodium hypophosphite Download PDFInfo
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- KWSLGOVYXMQPPX-UHFFFAOYSA-N 5-[3-(trifluoromethyl)phenyl]-2h-tetrazole Chemical compound FC(F)(F)C1=CC=CC(C2=NNN=N2)=C1 KWSLGOVYXMQPPX-UHFFFAOYSA-N 0.000 title claims abstract description 80
- 229910001379 sodium hypophosphite Inorganic materials 0.000 title claims abstract description 80
- 238000002360 preparation method Methods 0.000 title claims abstract description 16
- 238000010521 absorption reaction Methods 0.000 claims abstract description 192
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 104
- 230000000694 effects Effects 0.000 claims abstract description 93
- 239000007788 liquid Substances 0.000 claims abstract description 82
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical class O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 73
- 238000000034 method Methods 0.000 claims abstract description 61
- 230000008859 change Effects 0.000 claims abstract description 47
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims abstract description 45
- 238000006243 chemical reaction Methods 0.000 claims abstract description 37
- 239000000243 solution Substances 0.000 claims abstract description 28
- 230000008569 process Effects 0.000 claims abstract description 25
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 19
- 239000011574 phosphorus Substances 0.000 claims abstract description 19
- 239000003513 alkali Substances 0.000 claims abstract description 12
- 238000001953 recrystallisation Methods 0.000 claims abstract description 10
- 239000012043 crude product Substances 0.000 claims abstract description 9
- 238000010438 heat treatment Methods 0.000 claims abstract description 9
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims abstract description 8
- 239000000920 calcium hydroxide Substances 0.000 claims abstract description 8
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims abstract description 8
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims abstract description 8
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims abstract description 8
- 239000011499 joint compound Substances 0.000 claims abstract description 8
- 230000001105 regulatory effect Effects 0.000 claims abstract description 8
- 239000011790 ferrous sulphate Substances 0.000 claims abstract description 7
- 235000003891 ferrous sulphate Nutrition 0.000 claims abstract description 7
- 238000001179 sorption measurement Methods 0.000 claims abstract description 7
- 238000001914 filtration Methods 0.000 claims abstract description 6
- 238000000926 separation method Methods 0.000 claims abstract description 5
- 239000008394 flocculating agent Substances 0.000 claims abstract description 3
- 150000002500 ions Chemical class 0.000 claims description 54
- 229940085991 phosphate ion Drugs 0.000 claims description 33
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 22
- 230000001174 ascending effect Effects 0.000 claims description 18
- 239000000047 product Substances 0.000 claims description 18
- 238000000746 purification Methods 0.000 claims description 18
- 238000004422 calculation algorithm Methods 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 14
- 238000007477 logistic regression Methods 0.000 claims description 12
- 239000002994 raw material Substances 0.000 claims description 11
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 9
- NCPXQVVMIXIKTN-UHFFFAOYSA-N trisodium;phosphite Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])[O-] NCPXQVVMIXIKTN-UHFFFAOYSA-N 0.000 claims description 9
- 239000002585 base Substances 0.000 claims description 8
- 239000012535 impurity Substances 0.000 claims description 8
- 238000013507 mapping Methods 0.000 claims description 8
- 239000011259 mixed solution Substances 0.000 claims description 8
- 238000005259 measurement Methods 0.000 claims description 7
- 238000004590 computer program Methods 0.000 claims description 6
- 230000001502 supplementing effect Effects 0.000 claims description 6
- KFDLHDGFDLHFRW-UHFFFAOYSA-N [O-][N+](Br)=O Chemical compound [O-][N+](Br)=O KFDLHDGFDLHFRW-UHFFFAOYSA-N 0.000 claims description 5
- 230000001276 controlling effect Effects 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- 239000002250 absorbent Substances 0.000 claims description 4
- 230000002745 absorbent Effects 0.000 claims description 4
- 238000005273 aeration Methods 0.000 claims description 4
- 239000002904 solvent Substances 0.000 claims description 4
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 3
- 239000013078 crystal Substances 0.000 claims description 2
- 238000004090 dissolution Methods 0.000 claims description 2
- 238000010517 secondary reaction Methods 0.000 claims 1
- 239000007789 gas Substances 0.000 description 80
- XYFCBTPGUUZFHI-UHFFFAOYSA-N Phosphine Chemical compound P XYFCBTPGUUZFHI-UHFFFAOYSA-N 0.000 description 40
- 229910000073 phosphorus hydride Inorganic materials 0.000 description 20
- 239000010802 sludge Substances 0.000 description 10
- 238000005516 engineering process Methods 0.000 description 6
- 230000036541 health Effects 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000004458 analytical method Methods 0.000 description 4
- 230000006378 damage Effects 0.000 description 4
- 238000004821 distillation Methods 0.000 description 3
- 239000003814 drug Substances 0.000 description 3
- 230000006870 function Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 238000002835 absorbance Methods 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- -1 phosphate radical ion Chemical class 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 238000002759 z-score normalization Methods 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000003463 adsorbent Substances 0.000 description 1
- 239000003963 antioxidant agent Substances 0.000 description 1
- 230000003078 antioxidant effect Effects 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 230000000739 chaotic effect Effects 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
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- 230000007547 defect Effects 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
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- 238000009776 industrial production Methods 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
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- 238000012544 monitoring process Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- ACVYVLVWPXVTIT-UHFFFAOYSA-M phosphinate Chemical compound [O-][PH2]=O ACVYVLVWPXVTIT-UHFFFAOYSA-M 0.000 description 1
- 239000003755 preservative agent Substances 0.000 description 1
- 230000002335 preservative effect Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000002910 solid waste Substances 0.000 description 1
- 238000002798 spectrophotometry method Methods 0.000 description 1
- 238000012549 training Methods 0.000 description 1
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- Treating Waste Gases (AREA)
Abstract
The application relates to the field of sodium hypophosphite preparation, and provides a method and equipment for preparing high-purity sodium hypophosphite, wherein the method comprises the following steps: respectively adding the phosphorus mud, water and alkali into a reaction kettle to prepare a sodium hypophosphite crude product solution, collecting tail gas generated by an initial reaction through a buffer bottle, heating the tail gas through an adsorption column water bath to adsorb the tail gas, and then absorbing the desorbed tail gas by using an excessive brominated nitric acid absorption liquid, wherein the concentration of the brominated nitric acid absorption liquid is regulated and controlled according to the water bath temperature and the change of the concentration of phosphate ions in the tail gas treatment process; placing the sodium hypophosphite crude product solution, calcium hydroxide and ferrous sulfate into a reactor for oscillating reaction, adding a flocculating agent, then distilling and concentrating, and then carrying out recrystallization and separation to obtain sodium hypophosphite solution; recrystallizing, filtering and separating the sodium hypophosphite solution to prepare the high-purity sodium hypophosphite. The concentration of the brominated nitric acid absorption liquid is regulated and controlled, so that the tail gas treatment effect of the brominated nitric acid absorption liquid is improved.
Description
Technical Field
The application relates to the field of sodium hypophosphite preparation, in particular to a method and equipment for preparing high-purity sodium hypophosphite.
Background
The high-purity sodium hypophosphite is an important chemical raw material and is widely applied to the fields of food industry, chemical industry, medicine and the like. For example, in the food industry, high purity sodium hypophosphite is used as an antioxidant to extend the shelf life of food; in the chemical industry, high-purity sodium hypophosphite is used as a preservative to improve the corrosion resistance of chemical products; in the field of medicine, the high-purity sodium hypophosphite can be used as a slow release agent of medicines and the like. The high-purity sodium hypophosphite has very wide application and plays an extremely important role in daily life and production application.
In the existing preparation methods of high-purity sodium hypophosphite, most of the methods for preparing the high-purity sodium hypophosphite by taking the phosphorus sludge as a raw material are used for preparing the high-purity sodium hypophosphite, the phosphorus sludge is mixed solid waste generated in industrial production, and the method for preparing the high-purity sodium hypophosphite by taking the phosphorus sludge as the raw material not only effectively treats the phosphorus sludge, but also converts the phosphorus sludge into a product with economic value.
However, in the process of preparing high-purity sodium hypophosphite by taking the sludge phosphorus as a raw material, phosphine harmful gas with higher concentration is generated in the tail gas of chemical reaction, so that the environmental pollution is great, and the phosphine harmful gas is required to be purified and discharged in the process of preparing the high-purity sodium hypophosphite by taking the sludge phosphorus as the raw material. In the conventional method for removing phosphine harmful gas generated in the process of preparing high-purity sodium hypophosphite by taking phosphorus sludge as a raw material, most of the phosphine harmful gas is dephosphorized and purified by utilizing absorption liquid. However, the dephosphorization and purification effects of the absorption liquid on the phosphine harmful gas depend on the concentration of the absorption liquid, and the concentration of the absorption liquid is changed greatly due to the fact that the concentration of the absorption liquid is reduced quickly in the absorption reaction process, so that the dephosphorization and purification effects are poor, and the environment and the human health are endangered.
Disclosure of Invention
The application provides a preparation method and equipment of high-purity sodium hypophosphite, which are used for solving the problem that the dephosphorization purification effect is poor due to the fact that the concentration of absorption liquid is changed greatly, and the adopted technical scheme is as follows:
in a first aspect, one embodiment of the present application provides a method for preparing high purity sodium hypophosphite, comprising the steps of:
initial reaction: respectively adding the phosphorus mud, water and alkali serving as basic raw materials into a reaction kettle, heating, stirring and reacting to obtain a sodium hypophosphite crude product solution;
tail gas treatment: collecting tail gas generated by the initial reaction through a buffer bottle, heating the tail gas through an adsorption column in a water bath for adsorption, then absorbing the desorbed tail gas by using excessive brominated nitric acid absorption liquid, and regulating and controlling the concentration of the brominated nitric acid absorption liquid according to the water bath temperature and the change of the concentration of phosphate ions in the absorption liquid in the tail gas treatment process;
and (3) reacting again: aerating the sodium hypophosphite crude product solution, adding calcium hydroxide and ferrous sulfate, continuing to perform aeration treatment, and finally placing the sodium hypophosphite crude product solution in a reactor for oscillating reaction;
standing and removing impurities: adding a flocculating agent into the solution after the re-reaction for standing and impurity removal treatment to obtain a sodium phosphite and sodium hypophosphite mixed solution;
And (3) distilling and concentrating: distilling and concentrating the sodium phosphite and sodium hypophosphite mixed solution to obtain a crystal product;
and (3) recrystallizing and separating: adding a solvent into the crystallized product for dissolution, then adjusting the pH value, and carrying out recrystallization and filtration separation to obtain sodium phosphite solid and sodium hypophosphite solution dissolved in ethanol respectively;
distillation-recrystallization: dissolving sodium hypophosphite in ethanolAnd (3) carrying out distillation and recrystallization treatment to obtain the high-purity sodium hypophosphite.
Preferably, the mass ratio of the phosphorus mud, the water and the alkali in the initial reaction is 1:115:4, wherein the alkali is a mixture of sodium hydroxide and calcium hydroxide according to a molar ratio of 4:1.
Preferably, the temperature of the heating and stirring reaction in the initial reaction is 80The time was 6h.
Preferably, in the re-reaction, the mass ratio of the calcium hydroxide to the ferrous sulfate is 2.6:1, wherein the concentration of ferrous sulfate in the crude sodium hypophosphite solution is 5mg/mL, and the time of the shaking reaction is 44min.
Preferably, the flocculant is a polyaluminum chloride flocculant, the concentration of the flocculant in the solution after the re-reaction is 5mg/mL, and the standing and impurity removing time is 57min.
Preferably, the solvent added in the recrystallization separation is 92% ethanol solution, the pH is adjusted to 7.75, and the volume ratio of the ethanol solution to the crystallized product is 1.3:1.
Preferably, the method for regulating and controlling the concentration of the brominated nitric acid absorption liquid according to the water bath temperature and the change of the concentration of phosphate ions in the tail gas treatment process comprises the following steps:
taking a sequence formed by water bath temperature data according to the time ascending order as a water bath temperature time sequence, and taking a sequence formed by phosphate ion concentration data according to the time ascending order as a phosphate ion concentration time sequence;
taking a set formed by a first preset parameter with the smallest time interval between every two collection moments as an adjacent moment set of each collection moment;
taking the data point of each acquisition time in the phosphate ion concentration time sequence as the data point of the first target time, and taking the sequence formed by all the data points of the acquisition times in the adjacent time set of the first target time according to the time ascending order as the neighbor ion concentration sequence of the data points of the first target time; taking the first-order difference sequence of the neighbor ion concentration sequence as a neighbor ion concentration change sequence of a data point at a first target moment;
acquiring an exhaust gas purifying effect index and an absorption performance gain coefficient at each acquisition time according to a neighbor ion concentration sequence and a neighbor ion concentration change sequence of a data point at each acquisition time in the phosphate ion concentration time sequence; acquiring the residual absorption capacity intensity of each acquisition time according to the tail gas purifying effect index and the absorption performance gain coefficient of each acquisition time;
Taking a sample consisting of residual absorption capacity intensity at all acquisition moments as a residual absorption capacity intensity sample, taking the residual absorption capacity intensity sample as input of a maximum inter-class variance algorithm, obtaining a measurement threshold value of the residual absorption capacity intensity sample by using the maximum inter-class variance algorithm, and marking the residual absorption capacity intensity at each acquisition moment which is greater than or equal to or less than the measurement threshold value in the residual absorption capacity intensity sample as 0 and 1 respectively;
taking the residual absorption capacity intensity at all the acquisition time in the residual absorption capacity intensity sample and the result marked by the residual absorption capacity intensity at all the acquisition time as input of an LR logistic regression model, and obtaining a classification result of the residual absorption capacity intensity at all the acquisition time in the residual absorption capacity intensity sample by using the LR logistic regression model, wherein the classification result comprises a class with weak residual absorption capacity of the nitric bromide absorption liquid and a class with strong residual absorption capacity of the nitric bromide absorption liquid;
if the residual absorption capacity intensity at the current moment belongs to the category of weak residual absorption capacity of the brominated nitric acid absorption liquid, supplementing the concentration of the brominated nitric acid absorption liquid at the current moment; if the residual absorption capacity intensity at the current moment belongs to the category with strong residual absorption capacity of the brominated nitric acid absorption liquid, the concentration of the brominated nitric acid absorption liquid does not need to be supplemented at the current moment.
Preferably, the method for respectively obtaining the tail gas purifying effect index and the absorption performance gain coefficient at each collection time according to the neighbor ion concentration sequence and the neighbor ion concentration change sequence of the data point at each collection time in the phosphate ion concentration time sequence comprises the following steps:
calculating the absolute value of the difference between the data point value at the first target moment and each element value in the neighbor ion concentration sequence of the data point at the first target moment, calculating the average value of the sum of the absolute values on the neighbor ion concentration sequence, and taking the product of the average value and the information entropy of all the element values in the neighbor ion concentration sequence as the ion concentration increase change coefficient of the data point at the first target moment;
taking a negative mapping result taking a natural constant as a base and taking the ion concentration increase change coefficient as an index as a molecule; calculating the difference value between the maximum value and the minimum value in the neighbor ion concentration sequence of the data point at the first target moment, and taking the product of the difference value and the element mean value in the neighbor ion concentration sequence as a denominator;
calculating the opposite number of the ratio of the numerator to the denominator; taking the sum of the opposite number and the second preset parameter as an exhaust gas purifying effect index at a first target moment;
Taking the tail gas purifying effect indexes at all the acquisition moments as the input of a DPC density peak value clustering algorithm, and obtaining clustering results of the tail gas purifying effect indexes at all the acquisition moments by using the DPC density peak value clustering algorithm;
calculating element mean values in each cluster in the clustering result, and taking the cluster corresponding to the maximum element mean value as an optimal purifying effect cluster; taking a set formed by the acquisition moments of all elements in the optimal purification effect cluster as a target moment data set, and taking a set formed by the water bath temperatures of all the acquisition moments in the target moment data set as an optimal water bath temperature set;
for each data point at the acquisition time in the water bath temperature time sequence, calculating the difference value between the data point value at the acquisition time and each element value in the optimal water bath temperature set, and taking a sequence formed by all the difference values according to the ascending order of the values as a water bath temperature difference value sequence of the data points at the acquisition time;
taking a natural constant as a base number, and taking a negative mapping result with the variation coefficient of all element values in the water bath temperature difference value sequence as an index as a molecule; taking the absolute value of the difference between each element value and the last element value in the water bath temperature difference sequence as a first composition factor, and taking the sum of the first composition factor and a third preset parameter as a denominator; taking the sum of the opposite number of the ratio of the numerator and the denominator and a second preset parameter as a second composition factor, and taking the average value of the sum of the second composition factors on the water bath temperature difference value sequence as a water bath temperature discretization index of the data point at the acquisition time;
Taking a natural constant as a base number, taking a negative mapping result taking the average value of elements in the water bath temperature difference value sequence as an index as a numerator, taking the sum of the water bath temperature discretization index and a third preset parameter as a denominator, and taking the ratio of the numerator to the denominator as an absorption performance gain coefficient at the acquisition time.
Preferably, the method for obtaining the residual absorption capacity strength at each collection time according to the exhaust gas purifying effect index and the absorption performance gain coefficient at each collection time comprises the following steps:
taking each acquisition time as a second target time, forming a sequence of tail gas purifying effect indexes of all acquisition times in a neighboring time set of the second target time according to the ascending order of time as a purifying effect sequence of the second target time, and forming a sequence of absorption performance gain coefficients of all acquisition times in the neighboring time set of the second target time according to the ascending order of time as a gain change sequence of the second target time;
calculating the difference value between each element value and the last element value in the purifying effect sequence at the second target moment, and taking the average value of the sum of the difference values on the purifying effect sequence as the purifying effect trend index at the second target moment;
Calculating the difference value between each element value and the last element value in the gain change sequence at the second target moment, and taking the average value of the sum of the difference values on the gain change sequence as the gain trend index at the second target moment;
taking a negative mapping result taking a natural constant as a base and taking the sum of the purifying effect trend index and the gain trend index as an index as a molecule; taking the product of the element mean value in the purifying effect sequence, the element mean value in the gain change sequence and the element mean value in the neighbor ion concentration change sequence of the data point at the second target moment as denominator; the ratio of the numerator to the denominator is taken as the remaining absorbent capacity strength at the second target instant.
In a second aspect, an embodiment of the present application further provides a high-purity sodium hypophosphite preparation apparatus, including a memory, a processor, and a computer program stored in the memory and running on the processor, where the processor implements the steps of any one of the methods described above when the processor executes the computer program.
The beneficial effects of this application are: according to the method, the tail gas purifying effect index is obtained according to the change rule of the phosphate radical ion concentration time sequence, the optimal purifying effect cluster is obtained by utilizing the tail gas purifying effect index, the absorption performance gain coefficient is obtained according to the optimal purifying effect cluster and the water bath temperature time sequence, and the residual absorption capacity intensity is obtained according to the tail gas purifying effect index and the absorption performance gain coefficient. And obtaining a residual absorption capacity intensity sample by utilizing the residual absorption capacity intensity, and obtaining the supplementing time of the concentration of the brominated nitric acid absorption liquid based on the absorption capacity intensity sample by utilizing an LR logistic regression model, so as to prepare the high-purity sodium hypophosphite by utilizing the traditional process. The method has the beneficial effects that the influence of the change of the water bath temperature and the phosphate ion concentration on the absorption capacity of the brominated nitric acid absorption liquid is considered, the supplementing time of the concentration of the brominated nitric acid absorption liquid is optimized, the phenomenon that harmful gas is released and damages the environment and the human health due to the insufficient concentration of the brominated nitric acid absorption liquid is avoided, and the dephosphorization and the phosphine purification effects of the brominated nitric acid absorption liquid are improved.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a schematic flow chart of a method for preparing high purity sodium hypophosphite according to an embodiment of the present disclosure;
fig. 2 is a flow chart of an implementation of a method for preparing high purity sodium hypophosphite according to an embodiment of the present application.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
Referring to fig. 1, a flowchart of a method for preparing high purity sodium hypophosphite according to an embodiment of the present application is shown, and the method includes the following steps:
And S001, obtaining a water bath temperature time sequence and a phosphate ion concentration time sequence in the tail gas treatment process for preparing the high-purity sodium hypophosphite.
The method takes the sludge phosphorus as the raw material to prepare the high-purity sodium hypophosphite, the preparation raw material for preparing the high-purity sodium hypophosphite is selected to be the sludge phosphorus, water and alkali, and the absorption liquid of the chemical reaction tail gas is selected to be the brominated nitric acid absorption liquid.
In the traditional process for preparing high-purity sodium hypophosphite by taking phosphorus mud as a raw material, the phosphorus mud, water and alkali are added into a reaction kettle to carry out chemical reaction to prepare the high-purity sodium hypophosphite. However, the high-concentration phosphine harmful gas is generated in the chemical reaction process of the preparation, and the high-concentration phosphine harmful gas is required to be transmitted to the tail gas treatment equipment in the preparation process of the high-purity sodium hypophosphite to carry out dephosphorization purification treatment on the phosphine harmful gas and exhaust gas emission, so that the harm to the environment and human health is prevented. The process for preparing the high-purity sodium hypophosphite mixed solution by taking the phosphorus mud, the water and the alkali as raw materials comprises the following steps:
initial reaction: under the protection of nitrogen with the flow rate of 25mL/min, respectively adding the phosphorus mud, water and alkali into a reaction kettle according to the mass ratio of 1:115:4, and standing at 80Heating and stirring to react for 6 hours to prepare a crude sodium hypophosphite product solution, wherein the alkali is obtained by mixing sodium hydroxide and calcium hydroxide according to a molar ratio of 4:1.
Tail gas treatment: dephosphorizing, purifying and discharging chemical tail gas generated by chemical reaction, wherein the absorption liquid is brominated nitric acid absorption liquid. In the chemical tail gas treatment process, the tail gas generated in the chemical reaction is required to pass through a buffer bottle, a water bath kettle and a brominated nitric acid absorption liquid to control the flow rate of the tail gas and the absorption temperature of the tail gas, and meanwhile, the concentration of the brominated nitric acid absorption liquid is regulated and controlled so as to achieve the optimal tail gas absorption effect and avoid the leakage of harmful phosphine gas.
Specifically, the tail gas generated by the initial reaction is collected through a buffer bottle, the collected tail gas is adsorbed by an adsorption column filled with N2 adsorbent, then water bath heating is used for adsorption, and the desorbed tail gas is absorbed by excessive nitric bromide absorption liquid.
The application utilizes a temperature sensor to collect the water bath temperature of the water bath kettle, and simultaneously utilizes a spectrophotometry to collect the concentration of phosphate ions in the brominated nitric acid absorption liquid. In this application, gather time interval is 2s, gathers time length for 6h, and the practitioner can take value according to actual conditions. For the accuracy of the subsequent analysis, the time sequence formed by the collected water bath temperature and the phosphate ion concentration according to the ascending order of time is respectively used as a water bath temperature data sequence and a phosphate ion concentration data sequence. In order to avoid the influence of different dimensions on analysis results, the water bath temperature data sequence and the phosphate ion concentration data sequence are subjected to z-score normalization processing, so that a water bath temperature time sequence and a phosphate ion concentration time sequence are obtained, and the z-score normalization processing is a known technology, and the specific process is not repeated.
Thus, a water bath temperature time series and a phosphate ion concentration time series were obtained.
Step S002, obtaining a neighbor ion concentration change sequence according to the phosphate ion concentration time sequence, obtaining a tail gas purifying effect index according to the neighbor ion concentration change sequence, obtaining an optimal water bath temperature set according to the tail gas purifying effect index, and obtaining an absorption performance gain coefficient according to the water bath temperature time sequence and the optimal water bath temperature set.
In general, due to the complexity of the preparation time of the high-purity sodium hypophosphite, the water bath temperature can change, and the water bath temperature can influence the absorption efficiency of the brominated nitric acid absorption liquid on phosphine harmful gas, thereby influencing the concentration change of the brominated nitric acid absorption liquid. In order to cope with the phenomenon that the concentration of the brominated nitric acid is too low and the absorption efficiency of the phosphine harmful gas is too low due to the too high consumption of the brominated nitric acid, it is necessary to analyze the influence relationship of the water bath temperature on the absorption efficiency of the brominated nitric acid absorption liquid.
Specifically, the change of the concentration of phosphate ions in adjacent times reflects the absorption efficiency of the brominated nitric acid absorption liquid to a certain extent, in order to measure the capability of the brominated nitric acid absorption liquid to absorb phosphine harmful gas, each acquisition time is taken as a marking time, a set formed by K acquisition times with the smallest time interval between the acquisition times is taken as an adjacent time set of the marking times, and the empirical value of K is 50.
Further, a sequence formed by data points at all the time points in adjacent time sets of each collecting time in the phosphate ion concentration time sequence according to the ascending order of time is used as a neighbor ion concentration sequence of the data points at each collecting time. For the adjacent ion concentration sequence of each data point at the collection time in the phosphate ion concentration time sequence, taking the adjacent ion concentration sequence as the input of differential operation, taking the output of the differential operation as the first differential sequence of the adjacent ion concentration sequence, taking the first differential sequence of the adjacent ion concentration sequence as the adjacent ion concentration change sequence of the data point at the collection time, and the differential operation is a known technology, and the specific process is not repeated.
Further, the exhaust gas purifying effect index at each acquisition time is calculated:
in the method, in the process of the invention,ion concentration increase change coefficient of data point representing ith acquisition time in phosphate ion concentration time series, +.>Information entropy of all element values in a neighbor ion concentration sequence representing data points at the ith acquisition time in a phosphate ion concentration time sequence, +.>The number of element values in the neighbor ion concentration sequence representing data points at the ith acquisition instant in the phosphate ion concentration time sequence,/- >Values representing data points at the ith acquisition instant in the phosphate ion concentration time series, +.>A b-th element value in a neighbor ion concentration sequence representing a data point at an i-th acquisition time in the phosphate ion concentration time sequence;
an exhaust gas purifying effect index indicating the i-th acquisition time,/->Representing an exponential function based on natural constants, < ->Mean value of all elements in neighbor ion concentration change sequence of data points representing ith acquisition time in phosphate ion concentration time sequence, +.>And->Respectively representing the maximum value and the minimum value of elements in a neighbor ion concentration change sequence of data points at the ith acquisition time in the phosphate ion concentration time sequence. The calculation of the information entropy is a well-known technology, and the specific process is not repeated.
Differences between the value of the data point at the ith acquisition time in the phosphate ion concentration time series and the value of the b-th element in the neighbor ion concentration series of its data pointThe larger and the entropy of all the element values in the neighbor ion concentration sequence of the data point at the i-th acquisition instant in the phosphate ion concentration time sequence>The larger the information composition of the elements in the neighbor ion concentration sequence is, the more complex the information composition is, and the more chaotic the ion change is in a short period of time to a certain extent, because the brominated nitric acid can cause the increase of the concentration of phosphate ions when absorbing the harmful phosphine gas, namely the faster the concentration of phosphate ions is increased, the larger the ion concentration increase change coefficient is, namely the stronger the purifying and absorbing effects of the brominated nitric acid are at the moment. In addition, the average value of all elements in the neighbor ion concentration change sequence of the data point at the ith acquisition time in the phosphate ion concentration time sequence The larger and the difference between the maximum value and the minimum value of the elements in the neighbor ion concentration variation sequence +.>The larger the phosphate ion concentration increases faster in the adjacent time,at the same time, the ion concentration increase change coefficient of the data point at the ith acquisition time in the phosphate ion concentration time series +.>The larger the absorption effect of the brominated nitric acid absorption liquid is, the larger the exhaust gas purifying effect index is.
Further, in order to analyze the influence relationship of the water bath temperature on the absorption efficiency of the brominated nitric acid absorption liquid, a set of tail gas purifying effect indexes at all collection moments is used as a tail gas purifying effect data set, all data in the tail gas purifying effect data set are used as inputs of a DPC density peak clustering algorithm (Density Peaks Clustering, DPC), the output of the DPC density peak clustering algorithm is used as a clustering result of all data in the tail gas purifying effect data set, and the DPC density peak clustering algorithm is a known technology, and the specific process is not repeated.
Different clusters in the clustering results of all the data in the exhaust gas purifying effect data set reflect the exhaust gas purifying effect of different degrees, and the cluster with the largest element mean value reflects the exhaust gas purifying effect best due to the clustering analysis based on the set of the exhaust gas purifying effect indexes. Therefore, element mean values of all elements in each cluster in the clustering result are calculated, and the cluster corresponding to the maximum element mean value is used as the optimal purifying effect cluster. Since all elements in the optimal purification effect cluster are composed of the exhaust gas purification effect indexes at the acquisition time, it can be explained that each element in the optimal purification effect cluster corresponds to one acquisition time. Therefore, the collection composed of the collection moments corresponding to all elements in the optimal purification effect cluster is taken as a target moment data set, and the collection composed of the water bath temperatures at all collection moments in the target moment data set is taken as an optimal water bath temperature collection.
The phosphate ions in the brominated nitric acid absorption liquid change rapidly at the corresponding collection time of the water bath temperature in the optimal water bath temperature set, namely the brominated nitric acid absorption liquid has good absorption effect at the moment. Thus, it can be stated that the magnitude of the water bath temperature in the optimum set of water bath temperatures has a promoting effect on the absorption effect of the brominated nitric acid absorption solution.
Further, in order to reflect the promotion effect of the water bath temperature at each acquisition time on the absorption performance of the brominated nitric acid absorption liquid, for each data point at the acquisition time in the water bath temperature time sequence, calculating the difference value between the numerical value of the data point at the acquisition time and each element value in the optimal water bath temperature set, and taking a sequence formed by all the difference values according to the ascending order of the numerical values as a water bath temperature difference value sequence. Because the water bath temperature in the optimal water bath temperature set represents the optimal water bath temperature for promoting the absorption effect of the brominated nitric acid absorption liquid to a certain extent, the smaller the element values in the water bath temperature difference value sequence are, the more concentrated the element distribution is, which shows that the closer the water bath temperature at the moment is to the optimal water bath temperature, namely the stronger the promotion effect on the brominated nitric acid absorption liquid to absorb the harmful phosphine gas is.
Based on the water bath temperature difference sequence, the absorption performance gain coefficient of each acquisition time is calculated:
in the method, in the process of the invention,a water bath temperature discretization index indicating the data point of the ith acquisition time in the time series of water bath temperatures,/>The number of element values in the sequence of water bath temperature difference values representing the data points at the i-th acquisition instant in the sequence of water bath temperature times, respectively>Representing an exponential function based on natural constants, < ->Indicating a water bathCoefficient of variation of all element values in the sequence of water bath temperature difference values of the data points at the ith acquisition time in the temperature time sequence, +.>And->The g-th and (g-1) -th element values in the water bath temperature difference value sequence of the data points of the ith acquisition time in the water bath temperature time sequence are respectively represented by +.>Representing error parameters, wherein the value of the denominator is avoided to be 0, and the empirical value of the error parameters is 0.01;
an absorption gain factor indicating the i-th acquisition instant,/->The average of all element values in the water bath temperature difference sequence representing the data point at the ith acquisition time in the water bath temperature time sequence. The calculation of the coefficient of variation is a well-known technique, and the detailed process is not repeated.
The smaller the difference between the g-th and (g-1) -th element values in the water bath temperature difference value sequence of the data points at the i-th acquisition time in the water bath temperature time sequence, namely the first composition factor The smaller and the coefficient of variation of all element values in the sequence of water bath temperature differences +.>The smaller, i.e. the second component factor +.>The smaller the difference value sequence, the smaller the discreteness of the element distribution in the water bath temperature difference value sequence, and the distance between the water bath temperature at the moment and the average level of the optimal water bath temperature set is reflected to a certain extentThe smaller the water bath temperature discretization index is, namely the higher the gain of the water bath temperature at the moment to the absorption capacity of the brominated nitric acid absorption liquid is. In addition, the smaller the water bath temperature discretization index of the data point at the i-th acquisition time in the water bath temperature time series, and the average value of all the element values in the water bath temperature difference value series of the data point at the i-th acquisition time in the water bath temperature time series +.>The smaller the water bath temperature at this point, the closer the water bath temperature to the average level of the optimum water bath temperature set, and the better the gain effect on the absorption capacity of the brominated nitric acid absorption liquid at this point, the larger the absorption performance gain coefficient.
Thus, the tail gas purifying effect index and the absorption performance gain coefficient at each acquisition time are obtained.
Step S003, a purifying effect sequence and a gain change sequence are obtained according to the tail gas purifying effect index and the absorption performance gain coefficient, and the residual absorption capacity strength is obtained according to the purifying effect sequence and the gain change sequence.
Because the concentration of the brominated nitric acid absorption liquid can be rapidly reduced when the brominated nitric acid absorption liquid absorbs the phosphine harmful gas generated in the process of preparing the high-purity sodium hypophosphite, if the concentration of the brominated nitric acid absorption liquid is not timely supplemented, insufficient dephosphorization and purification treatment of the phosphine harmful gas can be caused, and great harm can be generated to the environment and human health. In addition, the larger the absorption performance gain index is, the larger the exhaust gas purifying effect index is, which means that the faster the concentration of the brominated nitric acid absorption liquid is consumed at the moment, the weaker the residual capability of the brominated nitric acid absorption liquid for absorbing harmful gases is; meanwhile, the greater the concentration of phosphate ions in the brominated nitric acid absorption liquid, the more the concentration of the brominated nitric acid ions is consumed at the moment, the weaker the residual capability of the brominated nitric acid absorption liquid for absorbing harmful gases is because the brominated nitric acid absorption liquid and the harmful gas of phosphine are reflected to generate phosphate ions.
Specifically, for each collection time, a sequence of exhaust gas purifying effect indexes at all times in a set of adjacent times to the collection time in an ascending order of time is used as a purifying effect sequence of the collection time. And similarly, taking a sequence formed by absorption performance gain coefficients at all the moments in adjacent moment sets of each acquisition moment according to the ascending order of time as a gain change sequence of each acquisition moment. It should be noted that, the purifying effect sequence and the gain change sequence at each collecting time respectively represent the changes of the tail gas purifying effect index and the absorption performance gain coefficient in the local time period, and if the purifying effect sequence and the gain change sequence show an ascending trend, it is indicated that the more serious the concentration consumption of the brominated nitric acid absorption liquid in the local time period is, the weaker the residual capability of the brominated nitric acid absorption liquid for absorbing harmful gas is.
Based on the above analysis, the remaining absorbent capacity intensity at each acquisition instant is calculated:
in the method, in the process of the invention,purifying effect trend index indicating the ith acquisition time,/->Representing the number of element values in the purification effect sequence at the ith acquisition instant,/for the purification effect sequence>And->Respectively representing the h and (h-1) th element values in the purifying effect sequence at the ith acquisition time;
gain trend index indicating the ith acquisition instant, < +.>Representing the number of element values in the gain variation sequence at the ith acquisition instant,/for the gain variation sequence>And->The k (k-1) th element value in the gain change sequence of the ith acquisition time;
indicating the remaining absorbent capacity strength at the ith acquisition instant +.>Representing an exponential function based on natural constants, < ->Element mean value of the purification effect sequence representing the ith acquisition instant, +.>Element mean value of gain variation sequence representing the ith acquisition instant, +.>An elemental mean of the sequence of neighbor ion concentrations representing the data point at the i-th acquisition time.
Difference between h and (h-1) th element values in the purification effect sequence at the i-th acquisition timeThe larger the exhaust gas purifying effect index, the more obvious the upward trend of the exhaust gas purifying effect index is shown in the purifying effect sequence, and the larger the purifying effect index is. In addition, the kth, k, in the gain change sequence at the ith acquisition time, Difference between the values of the (k-1) th element +.>The larger the gain variation sequence, the more obvious the rising trend of the absorption performance gain coefficient is, the larger the gain trend index is. Therefore, the sum of the purifying effect trend index and the gain trend index at the ith acquisition time +.>The larger the tail gas purifying effect index and the absorption performance gain coefficient in the local time period of the ith acquisition time are, namely the larger the consumption of the concentration of the brominated nitric acid absorption liquid is, the weaker the residual absorption capacity is; and the element mean value of the purification effect sequence at the ith acquisition instant +.>The larger the element mean of the gain variation sequence +.>The larger the exhaust gas purifying effect index and the higher the average level of the absorption performance gain coefficient are, namely the faster the concentration of the brominated nitric acid absorption liquid is consumed, and the weaker the residual absorption capacity is at the moment; element mean of neighbor ion concentration sequence of data points at the ith acquisition timeThe larger the average level of the phosphate ion concentration in the brominated nitric acid absorption liquid, the higher the concentration of the brominated nitric acid absorption liquid which is already consumed at this time, that is, the weaker the residual absorption capacity of the brominated nitric acid absorption liquid at this time, the lower the residual absorption capacity intensity.
So far, the remaining absorption capacity intensity at each acquisition instant is obtained.
And S004, obtaining a residual absorption capacity intensity sample according to the residual absorption capacity intensity, and regulating and controlling the concentration of the brominated nitric acid absorption liquid at the current moment based on the residual absorption capacity intensity sample by utilizing an LR logistic regression model to finish the preparation of the high-purity sodium hypophosphite.
Further, taking the samples consisting of the residual absorption capacity intensities at all the acquisition moments as residual absorption capacity intensity samples, taking all the elements in the residual absorption capacity intensity samples as the input of a maximum inter-class variance algorithm, taking the output of the maximum accumulation variance algorithm as the measurement threshold of the residual absorption capacity intensity samples, wherein the maximum inter-class variance algorithm is a known technology, and the specific process is not repeated. Marking each element greater than or equal to the measurement threshold value in the residual absorption capacity intensity sample as 0, wherein the residual absorption capacity of the brominated nitric acid absorption liquid is higher; each element in the residual absorbance intensity sample that is less than the measurement threshold is labeled 1, representing a weaker residual absorbance of the brominated nitric acid absorber. A flow chart of an implementation of the present application is shown in fig. 2.
Further, the remaining absorption capacity intensity samples are used as input of an LR logistic regression model (Logistic regression, LR) and the LR logistic regression model is trained, and the training of the LR logistic regression model is a well-known technique, and the specific process is not repeated. The residual absorption capacity intensity at each moment in the tail gas treatment process of the traditional process for preparing the high-purity sodium hypophosphite is monitored, the trained LR logistic regression model is utilized to classify the residual absorption capacity intensity at all the acquisition moments in the tail gas treatment process to obtain a classification result, the classification result comprises a class with weak residual absorption capacity of the brominated nitric acid absorption liquid and a class with strong residual absorption capacity of the brominated nitric acid absorption liquid, and the LR logistic regression model is a known technology, and specific processes are not repeated.
The method comprises the steps of monitoring the residual absorption capacity intensity at the current moment in real time, and supplementing the concentration of the brominated nitric acid absorption liquid at the current moment if the residual absorption capacity intensity at the current moment belongs to the category with weaker residual absorption capacity of the brominated nitric acid absorption liquid; if the residual absorption capacity intensity at the current moment belongs to the category with stronger residual absorption capacity of the brominated nitric acid absorption liquid, the concentration of the brominated nitric acid absorption liquid does not need to be supplemented at the current moment.
So far, the time for supplementing the concentration of the brominated nitric acid absorption liquid is optimized, and the defects of insufficient dephosphorization and purification treatment of phosphine gas and harm to the environment and human health caused by the lower concentration of the brominated nitric acid absorption liquid are avoided.
After the treatment of the phosphine harmful gas generated by the chemical reaction is finished, a mixed solution for preparing high-purity sodium hypophosphite is obtained, and then the high-purity sodium hypophosphite is prepared through the following steps:
and (3) reacting again: 100mL of sodium hypophosphite crude product solution is taken and placed in a reactor, aeration treatment is carried out for 5.5 hours, then 1.3g Ca (OH) 2 and 0.5g FeSO4 are added into the solution, the pH value is adjusted to 11.5, aeration treatment is carried out for 11 hours, and then oscillation reaction is carried out for 44 minutes.
Standing and removing impurities: 1.5mg of polyaluminum chloride flocculant (Poly aluminum Chloride, PAC) is added into the solution after the re-reaction is completed, and the mixture is kept stand for 57min, filtered and purified to obtain a mixed solution of sodium phosphite and sodium hypophosphite.
And (3) distilling and concentrating: taking 50mL of mixed solution of sodium phosphite and sodium hypophosphite obtained after filtering and removing impurities at 100Concentrating by distillation, and then concentrating at 65->Crystallizing to obtain the crystallized product.
And (3) recrystallizing and separating: 65mL of 92% by mass ethanol solution was added to the concentrated crystalline product by distillation at 42Dissolving the crystallized product at a pH of 7.75 at 75 +>And recrystallizing to obtain sodium phosphite solid and sodium hypophosphite solution dissolved in ethanol.
And (3) preparing by recrystallization: dissolving sodium hypophosphite in ethanol at 70Recrystallizing, and filtering to obtain high puritySodium hypophosphite.
Based on the same inventive concept as the above method, the embodiment of the present application further provides a high-purity sodium hypophosphite preparation apparatus, which includes a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements the steps of any one of the above methods for preparing high-purity sodium hypophosphite when executing the computer program.
In this specification, each embodiment is described in a progressive manner, and identical and similar parts of each embodiment are all referred to each other, and each embodiment mainly describes differences from other embodiments. The foregoing description of the preferred embodiments of the present application is not intended to be limiting, but rather is intended to cover any and all modifications, equivalents, alternatives, and improvements within the principles of the present application.
Claims (10)
1. The preparation method of the high-purity sodium hypophosphite is characterized by comprising the following steps of:
initial reaction: respectively adding the phosphorus mud, water and alkali serving as basic raw materials into a reaction kettle, heating, stirring and reacting to obtain a sodium hypophosphite crude product solution;
tail gas treatment: collecting tail gas generated by the initial reaction through a buffer bottle, heating the tail gas through an adsorption column in a water bath for adsorption, then absorbing the desorbed tail gas by using excessive brominated nitric acid absorption liquid, and regulating and controlling the concentration of the brominated nitric acid absorption liquid according to the water bath temperature and the change of the concentration of phosphate ions in the absorption liquid in the tail gas treatment process;
and (3) reacting again: aerating the sodium hypophosphite crude product solution, adding calcium hydroxide and ferrous sulfate, continuing to perform aeration treatment, and finally placing the sodium hypophosphite crude product solution in a reactor for oscillating reaction;
Standing and removing impurities: adding a flocculating agent into the solution after the secondary reaction for standing, filtering and removing impurities to obtain a sodium phosphite and sodium hypophosphite mixed solution;
and (3) distilling and concentrating: distilling and concentrating the sodium phosphite and sodium hypophosphite mixed solution to obtain a crystal product;
and (3) recrystallizing and separating: adding a solvent into the crystallized product for dissolution, then adjusting the pH value, and carrying out recrystallization and filtration separation to obtain sodium phosphite solid and sodium hypophosphite solution dissolved in ethanol respectively;
and (3) preparing by recrystallization: and (3) carrying out distillation-recrystallization treatment on the sodium hypophosphite solution dissolved in ethanol to obtain high-purity sodium hypophosphite.
2. The method for preparing high-purity sodium hypophosphite according to claim 1, wherein the mass ratio of the phosphorus mud to the water to the alkali in the initial reaction is 1:115:4, and the alkali is a mixture of sodium hydroxide and calcium hydroxide according to a molar ratio of 4:1.
3. The method for preparing high purity sodium hypophosphite according to claim 1, wherein the temperature of the heating and stirring reaction in the initial reaction is 80The time was 6h.
4. The method for preparing high-purity sodium hypophosphite according to claim 1, wherein the mass ratio of calcium hydroxide to ferrous sulfate in the re-reaction is 2.6:1, wherein the concentration of ferrous sulfate in the crude sodium hypophosphite solution is 5mg/mL, and the time of the shaking reaction is 44min.
5. The method for preparing high-purity sodium hypophosphite according to claim 1, wherein the flocculant is polyaluminum chloride flocculant, the concentration of the flocculant in the solution after the re-reaction is 0.015mg/mL, and the standing and impurity removing time is 57min.
6. The method for preparing high purity sodium hypophosphite according to claim 1, wherein the solvent added in the recrystallization separation is 92% ethanol solution, the pH is adjusted to 7.75, and the volume ratio of the ethanol solution to the crystallized product is 1.3:1.
7. the method for preparing high-purity sodium hypophosphite according to claim 1, wherein the method for regulating and controlling the concentration of the brominated nitric acid absorption liquid according to the water bath temperature and the change of the concentration of phosphate ions in the tail gas treatment process comprises the following steps:
taking a sequence formed by water bath temperature data according to the time ascending order as a water bath temperature time sequence, and taking a sequence formed by phosphate ion concentration data according to the time ascending order as a phosphate ion concentration time sequence;
taking a set formed by a first preset parameter with the smallest time interval between every two collection moments as an adjacent moment set of each collection moment;
Taking the data point of each acquisition time in the phosphate ion concentration time sequence as the data point of the first target time, and taking the sequence formed by all the data points of the acquisition times in the adjacent time set of the first target time according to the time ascending order as the neighbor ion concentration sequence of the data points of the first target time; taking the first-order difference sequence of the neighbor ion concentration sequence as a neighbor ion concentration change sequence of a data point at a first target moment;
acquiring an exhaust gas purifying effect index and an absorption performance gain coefficient at each acquisition time according to a neighbor ion concentration sequence and a neighbor ion concentration change sequence of a data point at each acquisition time in the phosphate ion concentration time sequence; acquiring the residual absorption capacity intensity of each acquisition time according to the tail gas purifying effect index and the absorption performance gain coefficient of each acquisition time;
taking a sample consisting of residual absorption capacity intensity at all acquisition moments as a residual absorption capacity intensity sample, taking the residual absorption capacity intensity sample as input of a maximum inter-class variance algorithm, obtaining a measurement threshold value of the residual absorption capacity intensity sample by using the maximum inter-class variance algorithm, and marking the residual absorption capacity intensity at each acquisition moment which is greater than or equal to or less than the measurement threshold value in the residual absorption capacity intensity sample as 0 and 1 respectively;
Taking the residual absorption capacity intensity at all the acquisition time in the residual absorption capacity intensity sample and the result marked by the residual absorption capacity intensity at all the acquisition time as input of an LR logistic regression model, and obtaining a classification result of the residual absorption capacity intensity at all the acquisition time in the residual absorption capacity intensity sample by using the LR logistic regression model, wherein the classification result comprises a class with weak residual absorption capacity of the nitric bromide absorption liquid and a class with strong residual absorption capacity of the nitric bromide absorption liquid;
if the residual absorption capacity intensity at the current moment belongs to the category of weak residual absorption capacity of the brominated nitric acid absorption liquid, supplementing the concentration of the brominated nitric acid absorption liquid at the current moment; if the residual absorption capacity intensity at the current moment belongs to the category with strong residual absorption capacity of the brominated nitric acid absorption liquid, the concentration of the brominated nitric acid absorption liquid does not need to be supplemented at the current moment.
8. The method for preparing high-purity sodium hypophosphite according to claim 7, wherein the method for respectively obtaining the tail gas purifying effect index and the absorption performance gain coefficient at each collection time according to the neighbor ion concentration sequence and the neighbor ion concentration variation sequence of the data point at each collection time in the phosphate ion concentration time sequence comprises the following steps:
Calculating the absolute value of the difference between the data point value at the first target moment and each element value in the neighbor ion concentration sequence of the data point at the first target moment, calculating the average value of the sum of the absolute values on the neighbor ion concentration sequence, and taking the product of the average value and the information entropy of all the element values in the neighbor ion concentration sequence as the ion concentration increase change coefficient of the data point at the first target moment;
taking a negative mapping result taking a natural constant as a base and taking the ion concentration increase change coefficient as an index as a molecule; calculating the difference value between the maximum value and the minimum value in the neighbor ion concentration sequence of the data point at the first target moment, and taking the product of the difference value and the element mean value in the neighbor ion concentration sequence as a denominator;
calculating the opposite number of the ratio of the numerator to the denominator; taking the sum of the opposite number and the second preset parameter as an exhaust gas purifying effect index at a first target moment;
taking the tail gas purifying effect indexes at all the acquisition moments as the input of a DPC density peak value clustering algorithm, and obtaining clustering results of the tail gas purifying effect indexes at all the acquisition moments by using the DPC density peak value clustering algorithm;
calculating element mean values in each cluster in the clustering result, and taking the cluster corresponding to the maximum element mean value as an optimal purifying effect cluster; taking a set formed by the acquisition moments of all elements in the optimal purification effect cluster as a target moment data set, and taking a set formed by the water bath temperatures of all the acquisition moments in the target moment data set as an optimal water bath temperature set;
For each data point at the acquisition time in the water bath temperature time sequence, calculating the difference value between the data point value at the acquisition time and each element value in the optimal water bath temperature set, and taking a sequence formed by all the difference values according to the ascending order of the values as a water bath temperature difference value sequence of the data points at the acquisition time;
taking a natural constant as a base number, and taking a negative mapping result with the variation coefficient of all element values in the water bath temperature difference value sequence as an index as a molecule; taking the absolute value of the difference between each element value and the last element value in the water bath temperature difference sequence as a first composition factor, and taking the sum of the first composition factor and a third preset parameter as a denominator; taking the sum of the opposite number of the ratio of the numerator and the denominator and a second preset parameter as a second composition factor, and taking the average value of the sum of the second composition factors on the water bath temperature difference value sequence as a water bath temperature discretization index of the data point at the acquisition time;
taking a natural constant as a base number, taking a negative mapping result taking the average value of elements in the water bath temperature difference value sequence as an index as a numerator, taking the sum of the water bath temperature discretization index and a third preset parameter as a denominator, and taking the ratio of the numerator to the denominator as an absorption performance gain coefficient at the acquisition time.
9. The method for preparing high purity sodium hypophosphite according to claim 7, wherein the method for obtaining the residual absorption capacity intensity at each collection time according to the exhaust gas purifying effect index and the absorption performance gain coefficient at each collection time comprises the steps of:
taking each acquisition time as a second target time, forming a sequence of tail gas purifying effect indexes of all acquisition times in a neighboring time set of the second target time according to the ascending order of time as a purifying effect sequence of the second target time, and forming a sequence of absorption performance gain coefficients of all acquisition times in the neighboring time set of the second target time according to the ascending order of time as a gain change sequence of the second target time;
calculating the difference value between each element value and the last element value in the purifying effect sequence at the second target moment, and taking the average value of the sum of the difference values on the purifying effect sequence as the purifying effect trend index at the second target moment;
calculating the difference value between each element value and the last element value in the gain change sequence at the second target moment, and taking the average value of the sum of the difference values on the gain change sequence as the gain trend index at the second target moment;
Taking a negative mapping result taking a natural constant as a base and taking the sum of the purifying effect trend index and the gain trend index as an index as a molecule; taking the product of the element mean value in the purifying effect sequence, the element mean value in the gain change sequence and the element mean value in the neighbor ion concentration change sequence of the data point at the second target moment as denominator; the ratio of the numerator to the denominator is taken as the remaining absorbent capacity strength at the second target instant.
10. A high purity sodium hypophosphite preparation apparatus comprising a memory, a processor and a computer program stored in said memory and running on said processor, characterized in that said processor, when executing said computer program, realizes the steps of a high purity sodium hypophosphite preparation method according to any one of claims 1-9.
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| CN102502545A (en) * | 2011-11-24 | 2012-06-20 | 昆明理工大学 | Method for preparing sodium hypophosphite |
| CN103086334A (en) * | 2012-09-19 | 2013-05-08 | 广州金凯新材料有限公司 | Preparation method of high-concentration hypophosphorous acid |
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| CN101653692A (en) * | 2009-06-19 | 2010-02-24 | 昆明理工大学 | Method for comprehensively utilizing tail gas of sludge phosphorus-prepared sodium hypophosphite |
| CN102502545A (en) * | 2011-11-24 | 2012-06-20 | 昆明理工大学 | Method for preparing sodium hypophosphite |
| CN103086334A (en) * | 2012-09-19 | 2013-05-08 | 广州金凯新材料有限公司 | Preparation method of high-concentration hypophosphorous acid |
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