CN117902555A - Method for producing phosphoric acid by using corn soaking water - Google Patents
Method for producing phosphoric acid by using corn soaking water Download PDFInfo
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- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 title claims abstract description 214
- 229910000147 aluminium phosphate Inorganic materials 0.000 title claims abstract description 107
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 56
- 235000005824 Zea mays ssp. parviglumis Nutrition 0.000 title claims abstract description 30
- 235000002017 Zea mays subsp mays Nutrition 0.000 title claims abstract description 30
- 235000005822 corn Nutrition 0.000 title claims abstract description 30
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 23
- 238000002791 soaking Methods 0.000 title claims abstract description 19
- 240000008042 Zea mays Species 0.000 title claims description 28
- 238000000605 extraction Methods 0.000 claims abstract description 124
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 45
- 230000007062 hydrolysis Effects 0.000 claims abstract description 42
- 238000006460 hydrolysis reaction Methods 0.000 claims abstract description 42
- SQUHHTBVTRBESD-UHFFFAOYSA-N Hexa-Ac-myo-Inositol Natural products CC(=O)OC1C(OC(C)=O)C(OC(C)=O)C(OC(C)=O)C(OC(C)=O)C1OC(C)=O SQUHHTBVTRBESD-UHFFFAOYSA-N 0.000 claims abstract description 41
- CDAISMWEOUEBRE-GPIVLXJGSA-N inositol Chemical compound O[C@H]1[C@H](O)[C@@H](O)[C@H](O)[C@H](O)[C@@H]1O CDAISMWEOUEBRE-GPIVLXJGSA-N 0.000 claims abstract description 41
- 229960000367 inositol Drugs 0.000 claims abstract description 41
- CDAISMWEOUEBRE-UHFFFAOYSA-N scyllo-inosotol Natural products OC1C(O)C(O)C(O)C(O)C1O CDAISMWEOUEBRE-UHFFFAOYSA-N 0.000 claims abstract description 41
- 238000001914 filtration Methods 0.000 claims abstract description 39
- WPEXVRDUEAJUGY-UHFFFAOYSA-B hexacalcium;(2,3,4,5,6-pentaphosphonatooxycyclohexyl) phosphate Chemical compound [Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[Ca+2].[O-]P([O-])(=O)OC1C(OP([O-])([O-])=O)C(OP([O-])([O-])=O)C(OP([O-])([O-])=O)C(OP([O-])([O-])=O)C1OP([O-])([O-])=O WPEXVRDUEAJUGY-UHFFFAOYSA-B 0.000 claims abstract description 28
- 239000000706 filtrate Substances 0.000 claims abstract description 26
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 25
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 24
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 18
- 239000000047 product Substances 0.000 claims abstract description 17
- 239000007788 liquid Substances 0.000 claims abstract description 14
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 12
- 239000012535 impurity Substances 0.000 claims abstract description 12
- 230000001376 precipitating effect Effects 0.000 claims abstract description 11
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims abstract description 9
- 239000008213 purified water Substances 0.000 claims abstract description 9
- 238000004064 recycling Methods 0.000 claims abstract description 5
- 239000012071 phase Substances 0.000 claims description 56
- 238000004042 decolorization Methods 0.000 claims description 32
- 238000006243 chemical reaction Methods 0.000 claims description 23
- 239000007787 solid Substances 0.000 claims description 20
- 238000001728 nano-filtration Methods 0.000 claims description 18
- 239000002904 solvent Substances 0.000 claims description 18
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical group CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 claims description 14
- 239000002244 precipitate Substances 0.000 claims description 11
- GNFTZDOKVXKIBK-UHFFFAOYSA-N 3-(2-methoxyethoxy)benzohydrazide Chemical compound COCCOC1=CC=CC(C(=O)NN)=C1 GNFTZDOKVXKIBK-UHFFFAOYSA-N 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 10
- 239000000413 hydrolysate Substances 0.000 claims description 10
- 238000002156 mixing Methods 0.000 claims description 10
- 238000004537 pulping Methods 0.000 claims description 10
- 230000035484 reaction time Effects 0.000 claims description 10
- 230000020477 pH reduction Effects 0.000 claims description 9
- 239000012141 concentrate Substances 0.000 claims description 8
- 239000012530 fluid Substances 0.000 claims description 8
- 239000012528 membrane Substances 0.000 claims description 8
- 239000012452 mother liquor Substances 0.000 claims description 8
- 238000006386 neutralization reaction Methods 0.000 claims description 8
- 239000013049 sediment Substances 0.000 claims description 8
- 239000008346 aqueous phase Substances 0.000 claims description 7
- STCOOQWBFONSKY-UHFFFAOYSA-N tributyl phosphate Chemical compound CCCCOP(=O)(OCCCC)OCCCC STCOOQWBFONSKY-UHFFFAOYSA-N 0.000 claims description 5
- 239000003795 chemical substances by application Substances 0.000 claims description 4
- FGUUSXIOTUKUDN-IBGZPJMESA-N C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 Chemical compound C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 FGUUSXIOTUKUDN-IBGZPJMESA-N 0.000 claims description 2
- 238000005119 centrifugation Methods 0.000 claims description 2
- 238000004062 sedimentation Methods 0.000 claims description 2
- 230000003472 neutralizing effect Effects 0.000 claims 1
- 229910052799 carbon Inorganic materials 0.000 abstract description 13
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 abstract description 5
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 5
- 239000011574 phosphorus Substances 0.000 abstract description 5
- 239000002351 wastewater Substances 0.000 abstract description 4
- 241000209149 Zea Species 0.000 abstract 2
- 230000003301 hydrolyzing effect Effects 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 36
- 238000000926 separation method Methods 0.000 description 8
- 239000012074 organic phase Substances 0.000 description 7
- 239000004744 fabric Substances 0.000 description 6
- 235000013305 food Nutrition 0.000 description 4
- IMQLKJBTEOYOSI-GPIVLXJGSA-N Inositol-hexakisphosphate Chemical compound OP(O)(=O)O[C@H]1[C@H](OP(O)(O)=O)[C@@H](OP(O)(O)=O)[C@H](OP(O)(O)=O)[C@H](OP(O)(O)=O)[C@@H]1OP(O)(O)=O IMQLKJBTEOYOSI-GPIVLXJGSA-N 0.000 description 3
- 229910019142 PO4 Inorganic materials 0.000 description 3
- YYRMJZQKEFZXMX-UHFFFAOYSA-L calcium bis(dihydrogenphosphate) Chemical compound [Ca+2].OP(O)([O-])=O.OP(O)([O-])=O YYRMJZQKEFZXMX-UHFFFAOYSA-L 0.000 description 3
- 229940062672 calcium dihydrogen phosphate Drugs 0.000 description 3
- 229910000389 calcium phosphate Inorganic materials 0.000 description 3
- 235000019691 monocalcium phosphate Nutrition 0.000 description 3
- 239000010452 phosphate Substances 0.000 description 3
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 229920002261 Corn starch Polymers 0.000 description 2
- 241000196324 Embryophyta Species 0.000 description 2
- IMQLKJBTEOYOSI-UHFFFAOYSA-N Phytic acid Natural products OP(O)(=O)OC1C(OP(O)(O)=O)C(OP(O)(O)=O)C(OP(O)(O)=O)C(OP(O)(O)=O)C1OP(O)(O)=O IMQLKJBTEOYOSI-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 239000008120 corn starch Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000003814 drug Substances 0.000 description 2
- 239000003792 electrolyte Substances 0.000 description 2
- 239000003337 fertilizer Substances 0.000 description 2
- 229940068041 phytic acid Drugs 0.000 description 2
- 235000002949 phytic acid Nutrition 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 235000019738 Limestone Nutrition 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 235000013361 beverage Nutrition 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 235000015872 dietary supplement Nutrition 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 229940079593 drug Drugs 0.000 description 1
- 239000000975 dye Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 239000012527 feed solution Substances 0.000 description 1
- 235000013373 food additive Nutrition 0.000 description 1
- 239000002778 food additive Substances 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 239000003002 pH adjusting agent Substances 0.000 description 1
- 239000002367 phosphate rock Substances 0.000 description 1
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 description 1
- 239000000467 phytic acid Substances 0.000 description 1
- 230000008635 plant growth Effects 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000004321 preservation Methods 0.000 description 1
- 239000003755 preservative agent Substances 0.000 description 1
- 230000002335 preservative effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Abstract
The invention belongs to the technical field of phosphoric acid production, and discloses a method for producing phosphoric acid by using corn soaking water, which comprises the steps of adding lime water into corn soaking water after impurity removal to neutralize to obtain calcium phytate, hydrolyzing the calcium phytate at 160-180 ℃ and 0.6-0.7 Mpa, adding concentrated sulfuric acid into hydrolysis liquid to acidify, removing calcium sulfate to obtain filtrate, extracting the filtrate with an extractant to obtain an extraction phase and a raffinate phase, precipitating and centrifuging the extraction Yu Xiangna with methanol or ethanol after filtering to obtain inositol, and recovering and continuously extracting centrifugate; the extracted phase is reversely extracted by purified water to obtain a dilute phosphoric acid solution, and the dilute phosphoric acid solution is decolorized by active carbon and then is concentrated in vacuum to obtain a phosphoric acid finished product. The invention has the advantages of simple production process and low running cost; the method has the advantages of fully recycling the phosphorus resources, less wastewater discharge, high product purity and wide application area.
Description
Technical Field
The invention belongs to the technical field of phosphoric acid production, and particularly relates to a method for producing phosphoric acid by using corn soaking water.
Background
Phosphoric acid is a chemical substance with a wide range of uses: in the food and beverage industry, phosphoric acid is used as a pH adjuster, preservative and nutritional supplement; in the chemical industry, phosphoric acid is an important catalyst and intermediate for many chemical reactions, and is widely used for the synthesis of organic compounds, drugs, dyes and plastics; in agriculture, phosphoric acid is an important fertilizer component that can provide the phosphorus element required by plants. It is used for soil improvement and plant growth promotion in the agricultural field; in the electronics industry, phosphoric acid can be used as an electrolyte and electrolyte for batteries, both for charging and discharging the batteries.
Currently, phosphoric acid commonly found on the market is classified into hot phosphoric acid and wet phosphoric acid according to the production method: phosphoric acid is obtained by a thermal method using raw materials such as phosphate ore and limestone through a series of grinding, roasting, oxidizing and absorbing processes. The phosphoric acid product has higher purity and is often used in industries such as chemical fertilizers, foods, pharmacy and the like, but the preparation process is complicated, the energy consumption is higher, more pollutants such as sulfur dioxide and the like are generated, and certain influence is caused on the environment. The wet-process phosphoric acid preparation process is relatively simple, phosphate ore and sulfuric acid are used as raw materials, and phosphoric acid products are obtained through the procedures of acidification, filtration, concentration and the like, so that the production cost is low, but the purity is relatively low, and the phosphoric acid contains impurities to a certain extent; therefore, wet phosphoric acid is widely used in the industrial fields of papermaking, metal surface treatment and the like.
Corn steep water is the waste produced in the wet process of producing corn starch, wherein the phytic acid (inositol hexaphosphate) content is about 1.5%. The corn soaking water of about 3500 ten thousand tons is produced annually by China as the biggest corn starch producing country in the world, and rich plant phosphorus resources are contained therein, so that the development potential is huge. At present, the process for recovering phytate from corn soaking water and producing inositol and phosphate through the procedures of hydrolysis, separation, crystallization and the like has more reports, but the process for producing phosphoric acid has fewer reports, and CN115160108A reports a process for preparing inositol and phosphoric acid, which has the defects of long process flow, incomplete hydrolysis, large wastewater discharge, low quality of phosphoric acid and the like.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: the method for producing the phosphoric acid by using the corn soaking water is simple in production process and low in operation cost; the phosphorus resource is fully recovered, the wastewater discharge amount is small, the product purity is high, and the application area is wide; has higher economic benefit and ecological benefit.
In order to solve the technical problems, the technical scheme of the invention is as follows:
A method for producing phosphoric acid by using corn steep water, comprising the following steps:
a. And (3) neutralization: removing suspended impurities from the corn soaking water through sedimentation, adding lime water to neutralize until the pH value of the feed liquid is 6-8, and filtering to obtain calcium phytate sediment;
b. Hydrolysis: putting the calcium phytate obtained in the step a into a feeding tank, adding water, pulping until the solid content is 20-30% wt, transferring into a hydrolysis kettle, introducing steam, heating to 160-180 ℃ and 0.6-0.7 MPa, preserving heat and maintaining pressure for hydrolysis for 10-12 h, and ending the hydrolysis until the pH value is 2-3 to obtain a hydrolysate;
c. Acidifying: adding 98.3% sulfuric acid into the hydrolysate obtained in the step b for acidification, reacting the sulfuric acid with calcium dihydrogen phosphate to generate insoluble calcium sulfate precipitate, wherein the molar ratio of the sulfuric acid to the calcium phytate is 5-6:1, the reaction temperature is 60-80 ℃, and the reaction time is 2-4 hours to obtain an acidified solution;
d. And (3) filtering: c, filtering the acidizing fluid obtained in the step c through a plate frame, and removing calcium sulfate precipitate to obtain filtrate for later use;
e. extraction: adding an extracting agent into the filtrate obtained in the step d for extraction reaction, wherein the extracting agent is n-butanol or tributyl phosphate, the extraction temperature is 50-70 ℃ and the extraction time is 1-2 h compared with O/A which is 4-6:1; the extraction phase (upper layer) is an organic soluble phase containing phosphoric acid, and the raffinate phase is an aqueous phase containing inositol, so that separation of inositol and phosphoric acid is realized;
f. Inositol treatment: concentrating the raffinate phase (water phase containing inositol) in the step e to a solid content of 10-15%wt through nanofiltration, adding solvent methanol or ethanol with the volume of 2-3 times of that of the concentrate, uniformly mixing, precipitating for 3-5 h, centrifuging at 1500-3000 rpm to obtain inositol, and combining the raffinate produced after recovering the solvent from the centrifuging mother liquor with the plate-frame filtrate obtained in the step d for extraction;
g. And (3) back extraction: adding purified water into the extraction phase (organic phase containing phosphoric acid) in the step e for reverse extraction, wherein the extraction times are 3-5 times compared with O/A=0.5-1:1, the extraction temperature is 50-70 ℃ and the extraction time is 0.2-0.5 h; the dilute phosphoric acid solution is obtained, and the raffinate phase generated by back extraction returns to the step e and is used as an extractant for recycling;
h. decoloring: adding activated carbon into the dilute phosphoric acid solution obtained in the step g for decolorization, wherein the dosage of the activated carbon is 10-20 kg/m 3, the decolorization temperature is 30-40 ℃ and the decolorization time is 0.5-1 h; filtering after the decolorization is finished to obtain dilute phosphoric acid decolorized solution;
i. Concentrating: carrying out vacuum concentration on the dilute phosphoric acid decolorized solution obtained in the step h to obtain a phosphoric acid finished product; vacuum concentration temperature is 80-90 deg.c and vacuum degree is-0.07 to-0.09 MPa.
Preferably, the feed solution in the step a is neutralized to a pH value of 7.
Preferably, in the step b, water is added for pulping until the solid content is 25% wt, then the pulp is transferred into a hydrolysis kettle, steam is introduced for heating to 170 ℃ and 0.65MPa, the hydrolysis is carried out under the conditions of heat preservation and pressure maintaining, the hydrolysis time is 11h, and the hydrolysis is finished until the pH value is 2.5.
Preferably, in the step c, the molar ratio of sulfuric acid to calcium phytate is 5.5:1, the reaction temperature is 70 ℃, and the reaction time is 3 hours.
Preferably, in the step d, the model number of the plate-and-frame filter is XMZGF200/1250-U, and the manufacturer is Jingjin equipment and stock company.
Preferably, in the step e, the extractant is n-butanol, the extraction temperature is 60 ℃ and the extraction time is 1.5h compared with the O/A of 5:1.
Preferably, in the step f, the solid content after nanofiltration concentration is 12.5% wt, and the aperture of the nanofiltration membrane is 100Da; adding 2.5 times of solvent methanol in the volume of the concentrated solution, uniformly mixing, and precipitating for 4 hours; centrifugation at 2500 rpm.
Preferably, in the step g, the reverse extraction is performed for 0.35h at the extraction temperature of 60 ℃ for 4 times compared with the O/A of 0.75:1.
Preferably, the activated carbon dosage in the step h is 15kg/m 3, the decoloring temperature is 35 ℃, and the decoloring time is 0.75h.
Preferably, the vacuum concentration in the step i is carried out at a temperature of 85 ℃ and a vacuum degree of-0.08 MPa.
The phosphoric acid produced by using the corn soaking water has the characteristic of high purity (75-85%wt), so that the phosphoric acid can be widely applied to the fields of food, medicine, electronics and the like.
Due to the adoption of the technical scheme, the invention has the beneficial effects that:
The invention further expands the source of high-quality phosphoric acid by utilizing phosphoric acid produced by corn soaking water generated in the corn deep processing process, slows down ecological damage and environmental pollution caused by phosphorite exploitation and a hot phosphoric acid process, and has simple production process and low operation cost; the phosphorus resource is fully recovered, the wastewater discharge amount is small, the product purity is high, and the application area is wide; therefore, the method has remarkable economic and ecological benefits.
Detailed Description
The technical scheme of the invention is further described below by combining examples:
example 1:
a. and (3) neutralization: settling 10m 3 corn soaking water to remove suspended impurities, adding lime water to neutralize the solution until the pH value of the solution is 6, and filtering to obtain 285 kg calcium phytate sediment;
b. Hydrolysis: adding the calcium phytate obtained in the step a into a charging tank, adding 400 liters of water, pulping until the solid content is 20%wt, transferring into a hydrolysis kettle, introducing steam, heating to 160 ℃ and 0.6MPa, preserving heat and pressure for hydrolysis for 12 hours, and ending the hydrolysis until the pH value is 2;
c. Acidifying: adding 45L of sulfuric acid with the concentration of 98.3% into the hydrolysate obtained in the step b for acidification, and reacting the sulfuric acid with calcium dihydrogen phosphate to generate insoluble calcium sulfate precipitate, wherein the molar ratio of the sulfuric acid to the calcium phytate is 5:1, and the reaction temperature is 60 ℃ and the reaction time is 4 hours;
d. and (3) filtering: filtering the acidizing fluid obtained in the step c through a plate frame (the aperture of a filter cloth is 300 meshes, the filtering pressure is 0.3 MPa), and removing calcium sulfate precipitate to obtain 500 liters of filtrate for later use;
e. extraction: d, adding tributyl phosphate into the plate-frame filtrate obtained in the step d for extraction reaction, wherein the extraction temperature is 50 ℃ and the extraction time is 2h when the extraction ratio O/A is 4:1; the extract phase (upper layer) is organic soluble phase containing phosphoric acid to obtain 2100L, and the raffinate phase is water phase containing inositol to obtain 400L, so as to realize separation of inositol and phosphoric acid;
f. Inositol treatment: concentrating the raffinate phase (water phase containing inositol) in the step e to have a solid content of 10%wt and 250 liters through nanofiltration (nanofiltration membrane cut-off molecular weight of 100 Da), adding solvent ethanol with the volume of 2 times of that of the concentrate, uniformly mixing, precipitating for 3 hours, centrifuging at 1500rpm to obtain 30 kg of inositol, and combining residual liquid generated after recovering the solvent from the centrifuging mother liquor with the plate-frame filtrate obtained in the step d for extraction;
g. And (3) back extraction: adding 4200 liters of purified water into the extraction phase (organic phase containing phosphoric acid) in the step e for reverse extraction, wherein the ratio of O/A of the reverse extraction to O/A is 0.5:1, the extraction times are 5 times, the extraction temperature is 50 ℃, and the extraction time is 0.5h; 21000 liters of dilute phosphoric acid solution is obtained, and a raffinate phase generated by back extraction is returned to the step e and is used as an extractant for recycling;
h. Decoloring: adding 210kg of active carbon into the dilute phosphoric acid solution obtained in the step g for decolorization, wherein the dosage of the active carbon is 10kg/m 3, and the decolorization temperature is 30 ℃ and the decolorization time is 1h; filtering after the decolorization is finished to obtain 21000 liters of dilute phosphoric acid decolorized solution;
i. concentrating: vacuum concentrating the dilute phosphoric acid decolorized solution obtained in the step h at the temperature of 80 ℃ and the vacuum degree of-0.07 MPa; the yield of the phosphoric acid product was 70 l at a concentration of 75% wt and 92%.
Example 2:
a. And (3) neutralization: settling 10m 3 corn soaking water to remove suspended impurities, adding lime water to neutralize the solution until the pH value of the solution is 8, and filtering to obtain 310 kg calcium phytate sediment;
b. Hydrolysis: adding the calcium phytate obtained in the step a into a charging tank, adding 200 liters of water, pulping until the solid content is 30% wt, transferring into a hydrolysis kettle, introducing steam, heating to 180 ℃ and 0.7MPa, preserving heat and pressure for hydrolysis for 10 hours, and ending the hydrolysis until the pH value is 3;
c. Acidifying: adding 55L of sulfuric acid with the concentration of 98.3% into the hydrolysate obtained in the step b for acidification, and reacting the sulfuric acid with calcium dihydrogen phosphate to generate insoluble calcium sulfate precipitate, wherein the molar ratio of the sulfuric acid to the calcium phytate is 6:1, and the reaction temperature is 80 ℃ and the reaction time is 2 hours;
d. And (3) filtering: filtering the acidizing fluid obtained in the step c through a plate frame (the aperture of a filter cloth is 300 meshes, the filtering pressure is 0.3 MPa), and removing calcium sulfate precipitate to obtain 400 liters of filtrate for later use;
e. Extraction: d, adding tributyl phosphate into the plate-frame filtrate obtained in the step d for extraction reaction, wherein the extraction temperature is 70 ℃ and the extraction time is 1h when the extraction ratio O/A is 6:1; the extraction phase (upper layer) is an organic soluble phase containing phosphoric acid to obtain 2500 liters, and the extraction residual phase is an aqueous phase containing inositol to obtain 300 liters, so that separation of inositol and phosphoric acid is realized;
f. Inositol treatment: concentrating the raffinate phase (water phase containing inositol) in the step e to a solid content of 15%wt and 185 liters by nanofiltration (nanofiltration membrane cut-off molecular weight of 100 Da), adding solvent ethanol with the volume of 3 times of that of the concentrate, uniformly mixing, precipitating for 5 hours, centrifuging at 3000rpm to obtain 29.5 kg of inositol, and combining residual liquid generated after recovering the solvent from the centrifuging mother liquor with the plate-frame filtrate obtained in the step d for extraction;
g. And (3) back extraction: adding 2500L of purified water into the extraction phase (organic phase containing phosphoric acid) in the step e for reverse extraction, wherein the O/A ratio of the reverse extraction is 1:1, the extraction times are 3 times, the extraction temperature is 70 ℃, and the extraction time is 0.2h; 7500 liters of dilute phosphoric acid solution is obtained, and the raffinate phase generated by back extraction returns to the step e and is used as an extractant for recycling;
h. decoloring: adding 150kg of active carbon into the dilute phosphoric acid solution obtained in the step g for decolorization, wherein the dosage of the active carbon is 20kg/m 3, and the decolorization temperature is 40 ℃ and the decolorization time is 0.5h; 7500 liters of dilute phosphoric acid decolorized solution is obtained by filtration after decolorization;
i. Concentrating: vacuum concentrating the dilute phosphoric acid decolorized solution obtained in the step h at 90 ℃ and the vacuum degree of-0.09 MPa; the yield of the phosphoric acid product was 65 l and 93% with a concentration of 80% wt.
Example 3:
a. and (3) neutralization: settling 10m 3 corn soaking water to remove suspended impurities, adding lime water to neutralize until the pH value of the feed liquid is 7, and filtering to obtain 300 kg calcium phytate sediment;
b. Hydrolysis: putting the calcium phytate obtained in the step a into a feeding tank, adding 300 kg of water, pulping until the solid content is 25% wt, transferring into a hydrolysis kettle, introducing steam, heating to 170 ℃ and 0.65MPa, preserving heat and pressure for hydrolysis for 11h, and ending the hydrolysis until the pH value is 2.5;
c. acidifying: adding 50L of sulfuric acid with the concentration of 98.3% into the hydrolysate obtained in the step b for acidification, wherein the molar ratio of the sulfuric acid to the calcium phytate is 5.5:1, and the reaction temperature is 70 ℃ and the reaction time is 3 hours;
d. And (3) filtering: filtering the acidizing fluid obtained in the step c through a plate frame (the aperture of a filter cloth is 300 meshes, the filtering pressure is 0.3 MPa), and removing calcium sulfate precipitate to obtain 450 liters of filtrate for later use;
e. Extraction: adding n-butanol into the plate and frame filtrate obtained in the step d for extraction reaction, wherein the extraction temperature is 60 ℃ and the extraction time is 1.5h compared with the O/A of the extraction reaction which is 5:1; the extract phase (upper layer) is an organic soluble phase containing phosphoric acid, 2300 liters is obtained, the raffinate phase is an aqueous phase containing inositol, 400 liters is obtained, and separation of inositol and phosphoric acid is realized;
f. Inositol treatment: concentrating the raffinate phase (water phase containing inositol) in the step e to a solid content of 12.5%wt through nanofiltration (nanofiltration membrane cut-off molecular weight of 100 Da), adding solvent methanol with the volume of 2.5 times of the concentrate, uniformly mixing, precipitating for 4 hours, centrifuging at 2500rpm to obtain 31 kg of inositol, and combining residual liquid generated after recovering the solvent from the centrifuging mother liquor with the plate-frame filtrate obtained in the step d for extraction;
g. And (3) back extraction: adding 3060L of purified water into the extraction phase (organic phase containing phosphoric acid) in the step e for reverse extraction, wherein the O/A ratio of the reverse extraction is 0.75:1, the extraction times are 4 times, the extraction temperature is 60 ℃, and the extraction time is 0.35h; 12240 liters of dilute phosphoric acid solution is obtained, and the raffinate phase generated by back extraction returns to the step e and is reused as an extractant;
h. decoloring: adding 103.5kg of active carbon into the dilute phosphoric acid solution obtained in the step g for decolorization, wherein the dosage of the active carbon is 15kg/m 3, the decolorization temperature is 35 ℃, and the decolorization time is 0.75h; after the decolorization is finished, 12240 liters of dilute phosphoric acid decolorized solution is obtained by filtration;
i. Concentrating: vacuum concentrating the dilute phosphoric acid decolorized solution obtained in the step h at a temperature of 85 ℃ and a vacuum degree of-0.08 MPa; the yield of the phosphoric acid product was found to be 93.5% in 60 liters with a concentration of 85% wt.
Example 4:
a. And (3) neutralization: settling 10m 3 corn soaking water to remove suspended impurities, adding lime water to neutralize until the pH value of the feed liquid is 7, and filtering to obtain 305 kg calcium phytate sediment;
b. Hydrolysis: putting the calcium phytate obtained in the step a into a feeding tank, adding 305 kg of water, pulping until the solid content is 25% wt, transferring into a hydrolysis kettle, introducing steam, heating to 180 ℃ and 0.7MPa, preserving heat and pressure for hydrolysis for 10h, and ending the hydrolysis until the pH value is 2.5;
c. acidifying: adding 50L of sulfuric acid with the concentration of 98.3% into the hydrolysate obtained in the step b for acidification, wherein the molar ratio of the sulfuric acid to the calcium phytate is 5.5:1, and the reaction temperature is 70 ℃ and the reaction time is 3 hours;
d. And (3) filtering: filtering the acidizing fluid obtained in the step c through a plate frame (the aperture of a filter cloth is 400 meshes, and the filtering pressure is 0.4 MPa), and removing calcium sulfate precipitate to obtain 460 liters of filtrate for later use;
e. Extraction: adding n-butanol into the plate and frame filtrate obtained in the step d for extraction reaction, wherein the extraction temperature is 60 ℃ and the extraction time is 1.5h compared with the O/A of the extraction reaction which is 5:1; the extract phase (upper layer) is organic soluble phase containing phosphoric acid, 2360L is obtained, the extract phase is aqueous phase containing inositol, 400L is obtained, and separation of inositol and phosphoric acid is realized;
f. Inositol treatment: concentrating the raffinate phase (water phase containing inositol) in the step e to a solid content of 12.5%wt through nanofiltration (nanofiltration membrane cut-off molecular weight of 100 Da), adding solvent methanol with the volume of 2.5 times of the concentrate, uniformly mixing, precipitating for 4 hours, centrifuging at 2500rpm to obtain 30.5 kg of inositol, and combining the residual liquid generated after recovering the solvent from the centrifuging mother liquor with the plate-frame filtrate obtained in the step d for extraction;
g. And (3) back extraction: adding 3150L of purified water into the extraction phase (organic phase containing phosphoric acid) in the step e for reverse extraction, wherein the O/A ratio of the reverse extraction is 0.75:1, the extraction times are 4 times, the extraction temperature is 60 ℃, and the extraction time is 0.35h; 12600 liters of dilute phosphoric acid solution is obtained, and the raffinate phase generated by back extraction returns to the step e and is reused as an extractant;
h. Decoloring: adding 189kg of active carbon into the dilute phosphoric acid solution obtained in the step g for decolorization, wherein the dosage of the active carbon is 15kg/m 3, the decolorization temperature is 35 ℃, and the decolorization time is 0.75h; 12600 liters of dilute phosphoric acid decolorized solution is obtained after the decolorization is finished;
i. Concentrating: vacuum concentrating the dilute phosphoric acid decolorized solution obtained in the step h at a temperature of 85 ℃ and a vacuum degree of-0.08 MPa; 58 liters of phosphoric acid product with a concentration of 85% wt are obtained in a yield of 90.4%.
Example 5:
a. and (3) neutralization: settling 10m 3 corn soaking water to remove suspended impurities, adding lime water to neutralize until the pH value of the feed liquid is 7, and filtering to obtain 300 kg calcium phytate sediment;
b. Hydrolysis: putting the calcium phytate obtained in the step a into a feeding tank, adding 300 kg of water, pulping until the solid content is 25% wt, transferring into a hydrolysis kettle, introducing steam, heating to 170 ℃ and 0.65MPa, preserving heat and pressure for hydrolysis for 11h, and ending the hydrolysis until the pH value is 2.5;
c. acidifying: adding 45L of sulfuric acid with the concentration of 98.3% into the hydrolysate obtained in the step b for acidification, wherein the molar ratio of the sulfuric acid to the calcium phytate is 5:1, and the reaction temperature is 70 ℃ and the reaction time is 3h;
d. And (3) filtering: filtering the acidizing fluid obtained in the step c through a plate frame (the aperture of a filter cloth is 400 meshes, and the filtering pressure is 0.4 MPa), and removing calcium sulfate precipitate to obtain 450 liters of filtrate for later use;
e. Extraction: d, adding tributyl phosphate into the plate-frame filtrate obtained in the step d for extraction reaction, wherein the extraction temperature is 60 ℃ and the extraction time is 1.5h compared with the O/A of the extraction reaction which is 5:1; the extract phase (upper layer) is an organic soluble phase containing phosphoric acid, 2300 liters is obtained, the raffinate phase is an aqueous phase containing inositol, 400 liters is obtained, and separation of inositol and phosphoric acid is realized;
f. Inositol treatment: concentrating the raffinate phase (water phase containing inositol) in the step e to a solid content of 12.5%wt through nanofiltration (nanofiltration membrane cut-off molecular weight of 100 Da), adding solvent methanol with the volume of 2.5 times of the concentrate, uniformly mixing, precipitating for 4 hours, centrifuging at 1500rpm to obtain 30.6 kg of inositol, and combining the raffinate produced after recovering the solvent from the centrifuging mother liquor with the plate-frame filtrate obtained in the step d for extraction;
g. And (3) back extraction: adding 3060L of purified water into the extraction phase (organic phase containing phosphoric acid) in the step e for reverse extraction, wherein the O/A ratio of the reverse extraction is 0.75:1, the extraction times are 4 times, the extraction temperature is 60 ℃, and the extraction time is 0.35h; 12240 liters of dilute phosphoric acid solution is obtained, and the raffinate phase generated by back extraction returns to the step e and is reused as an extractant;
h. decoloring: adding 103.5kg of active carbon into the dilute phosphoric acid solution obtained in the step g for decolorization, wherein the dosage of the active carbon is 15kg/m 3, the decolorization temperature is 35 ℃, and the decolorization time is 0.75h; after the decolorization is finished, 12240 liters of dilute phosphoric acid decolorized solution is obtained by filtration;
i. Concentrating: vacuum concentrating the dilute phosphoric acid decolorized solution obtained in the step h at a temperature of 85 ℃ and a vacuum degree of-0.08 MPa; 59 liters of phosphoric acid product with a concentration of 85% by weight was obtained in a yield of 91.9%.
Example 6:
a. And (3) neutralization: settling 10m 3 corn soaking water to remove suspended impurities, adding lime water to neutralize the solution until the pH value of the solution is 7.5, and filtering to obtain 310 kg calcium phytate sediment;
b. Hydrolysis: putting the calcium phytate obtained in the step a into a feeding tank, adding 310 kg of water, pulping until the solid content is 25% wt, transferring into a hydrolysis kettle, introducing steam, heating to 170 ℃ and 0.65MPa, preserving heat and pressure for hydrolysis for 11h, and ending the hydrolysis until the pH value is 2.8;
c. acidifying: adding 50L of sulfuric acid with the concentration of 98.3% into the hydrolysate obtained in the step b for acidification, wherein the molar ratio of the sulfuric acid to the calcium phytate is 5.5:1, and the reaction temperature is 60 ℃ and the reaction time is 4 hours;
d. And (3) filtering: filtering the acidizing fluid obtained in the step c through a plate frame (the aperture of a filter cloth is 300 meshes, the filtering pressure is 0.3 MPa), and removing calcium sulfate precipitate to obtain 450 liters of filtrate for later use;
e. Extraction: adding n-butanol into the plate and frame filtrate obtained in the step d for extraction reaction, wherein the extraction temperature is 60 ℃ and the extraction time is 1.5h compared with the O/A of the extraction reaction which is 5:1; the extract phase (upper layer) is an organic soluble phase containing phosphoric acid, 2300 liters is obtained, the raffinate phase is an aqueous phase containing inositol, 400 liters is obtained, and separation of inositol and phosphoric acid is realized;
f. Inositol treatment: concentrating the raffinate phase (water phase containing inositol) in the step e to a solid content of 12.5%wt through nanofiltration (nanofiltration membrane cut-off molecular weight of 100 Da), adding solvent ethanol with the volume of 2.5 times of the concentrate, uniformly mixing, precipitating for 4 hours, centrifuging at 2500rpm to obtain 30.3 kg of inositol, and combining the residual liquid generated after recovering the solvent from the centrifuging mother liquor with the plate-frame filtrate obtained in the step d for extraction;
g. And (3) back extraction: adding 3060L of purified water into the extraction phase (organic phase containing phosphoric acid) in the step e for reverse extraction, wherein the O/A ratio of the reverse extraction is 0.75:1, the extraction times are 4 times, the extraction temperature is 60 ℃, and the extraction time is 0.35h; 12240 liters of dilute phosphoric acid solution is obtained, and the raffinate phase generated by back extraction returns to the step e and is reused as an extractant;
h. decoloring: adding 103.5kg of active carbon into the dilute phosphoric acid solution obtained in the step g for decolorization, wherein the dosage of the active carbon is 15kg/m 3, the decolorization temperature is 35 ℃, and the decolorization time is 0.75h; after the decolorization is finished, 12240 liters of dilute phosphoric acid decolorized solution is obtained by filtration;
i. concentrating: vacuum concentrating the dilute phosphoric acid decolorized solution obtained in the step h at a temperature of 85 ℃ and a vacuum degree of-0.08 MPa; 62 liters of phosphoric acid product with a concentration of 80% by weight are obtained in a yield of 89.2%.
Analysis of results: the results of the tests of the products of examples 1 to 6 (the test methods were carried out according to the methods described in GB 3149-2004 "food additive phosphoric acid") are shown in Table 1.
TABLE 1 content yield of products of examples 1-6 and heavy metal detection results
The detection data of the examples 1-6 show that the content and the impurity content of the phosphoric acid produced by the process method of the invention all meet the food-grade phosphoric acid requirement in the national food safety standard; wherein the process conditions of example 3 are the best, the product yield is the highest, and the impurity content is the lowest.
It is to be understood that these examples are illustrative of the present application and are not intended to limit the scope of the present application. Furthermore, it should be understood that various changes and modifications can be made by one skilled in the art after reading the teachings of the present application, and such equivalents are intended to fall within the scope of the application as defined in the appended claims.
Claims (9)
1. A method for producing phosphoric acid by using corn soaking water is characterized in that: the method comprises the following steps:
a. And (3) neutralization: removing suspended impurities from the corn soaking water through sedimentation, adding lime water to neutralize until the pH value of the feed liquid is 6-8, and filtering to obtain calcium phytate sediment;
b. Hydrolysis: putting the calcium phytate obtained in the step a into a feeding tank, adding water, pulping until the solid content is 20-30% wt, transferring into a hydrolysis kettle, introducing steam, heating to 160-180 ℃ and 0.6-0.7 MPa, preserving heat and maintaining pressure for hydrolysis for 10-12 h, and ending the hydrolysis until the pH value is 2-3 to obtain a hydrolysate;
c. Acidifying: adding sulfuric acid with the concentration of 98.3% into the hydrolysate obtained in the step b for acidification, wherein the molar ratio of the sulfuric acid to the calcium phytate is 5-6:1, the reaction temperature is 60-80 ℃, and the reaction time is 2-4 hours to obtain acidified liquid;
d. And (3) filtering: c, filtering the acidizing fluid obtained in the step c through a plate frame, and removing calcium sulfate precipitate to obtain filtrate for later use;
e. extraction: adding an extracting agent into the filtrate obtained in the step d for extraction reaction, wherein the extracting agent is n-butanol or tributyl phosphate, the extraction temperature is 50-70 ℃ and the extraction time is 1-2 h compared with O/A which is 4-6:1; the extraction phase is an organic soluble phase containing phosphoric acid, and the raffinate phase is an aqueous phase containing inositol;
f. Inositol treatment: concentrating the raffinate phase in the step e to a solid content of 10-15%wt through nanofiltration, adding solvent methanol or ethanol with the volume of 2-3 times of that of the concentrate, uniformly mixing, precipitating for 3-5 hours, centrifuging at 1500-3000 rpm to obtain inositol, and combining residual liquid generated after recovering the solvent from the centrifuging mother liquor with the plate-frame filtrate obtained in the step d for extraction;
g. And (3) back extraction: adding purified water into the extraction phase in the step e for reverse extraction, wherein the ratio of O/A in the reverse extraction is 0.5-1:1, the extraction times are 3-5, the extraction temperature is 50-70 ℃, and the extraction time is 0.2-0.5 h; the dilute phosphoric acid solution is obtained, and the raffinate phase generated by back extraction returns to the step e and is used as an extractant for recycling;
h. decoloring: adding activated carbon into the dilute phosphoric acid solution obtained in the step g for decolorization, wherein the dosage of the activated carbon is 10-20 kg/m 3, the decolorization temperature is 30-40 ℃ and the decolorization time is 0.5-1 h; filtering after the decolorization is finished to obtain dilute phosphoric acid decolorized solution;
i. Concentrating: carrying out vacuum concentration on the dilute phosphoric acid decolorized solution obtained in the step h to obtain a phosphoric acid finished product; vacuum concentration temperature is 80-90 deg.c and vacuum degree is-0.07 to-0.09 MPa.
2. The method for producing phosphoric acid by using corn steep water as claimed in claim 1, wherein: and c, neutralizing the feed liquid in the step a to a pH value of 7.
3. The method for producing phosphoric acid by using corn steep water as claimed in claim 1, wherein: and b, adding water, pulping to a solid content of 25% by weight, transferring into a hydrolysis kettle, introducing steam, heating to 170 ℃ and a pressure of 0.65MPa, preserving heat and maintaining pressure for hydrolysis for 11h, and ending the hydrolysis until the pH value is 2.5.
4. The method for producing phosphoric acid by using corn steep water as claimed in claim 1, wherein: in the step c, the molar ratio of sulfuric acid to calcium phytate is 5.5:1, the reaction temperature is 70 ℃, and the reaction time is 3 hours.
5. The method for producing phosphoric acid by using corn steep water as claimed in claim 1, wherein: in the step e, the extractant is n-butanol, the extraction ratio O/A is 5:1, the extraction temperature is 60 ℃, and the extraction time is 1.5h.
6. The method for producing phosphoric acid by using corn steep water as claimed in claim 1, wherein: the solid content after nanofiltration concentration in the step f is 12.5 percent by weight, and the aperture of the nanofiltration membrane is 100Da; adding 2.5 times of solvent methanol in the volume of the concentrated solution, uniformly mixing, and precipitating for 4 hours; centrifugation at 2500 rpm.
7. The method for producing phosphoric acid by using corn steep water as claimed in claim 1, wherein: in the step g, the reverse extraction is performed for 4 times at the extraction temperature of 60 ℃ for 0.35h compared with the O/A ratio of 0.75:1.
8. The method for producing phosphoric acid by using corn steep water as claimed in claim 1, wherein: in the step h, the using amount of the activated carbon is 15kg/m 3, the decoloring temperature is 35 ℃, and the decoloring time is 0.75h.
9. The method for producing phosphoric acid by using corn steep water as claimed in claim 1, wherein: the temperature of vacuum concentration in the step i is 85 ℃, and the vacuum degree is-0.08 MPa.
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