CN115259933A - Iron phosphate mother liquor and washing water treatment method and system - Google Patents
Iron phosphate mother liquor and washing water treatment method and system Download PDFInfo
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- CN115259933A CN115259933A CN202210958288.8A CN202210958288A CN115259933A CN 115259933 A CN115259933 A CN 115259933A CN 202210958288 A CN202210958288 A CN 202210958288A CN 115259933 A CN115259933 A CN 115259933A
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- 238000000034 method Methods 0.000 title claims abstract description 194
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 178
- 239000012452 mother liquor Substances 0.000 title claims abstract description 140
- 238000005406 washing Methods 0.000 title claims abstract description 121
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 title claims abstract description 51
- 229910000398 iron phosphate Inorganic materials 0.000 title claims description 30
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 522
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 208
- 239000007788 liquid Substances 0.000 claims abstract description 178
- 238000010521 absorption reaction Methods 0.000 claims abstract description 142
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 claims abstract description 103
- 235000011114 ammonium hydroxide Nutrition 0.000 claims abstract description 83
- 238000001816 cooling Methods 0.000 claims abstract description 45
- 238000001704 evaporation Methods 0.000 claims abstract description 34
- 239000003337 fertilizer Substances 0.000 claims abstract description 31
- 230000008020 evaporation Effects 0.000 claims abstract description 29
- 238000002309 gasification Methods 0.000 claims abstract description 25
- 238000002425 crystallisation Methods 0.000 claims abstract description 23
- 230000008025 crystallization Effects 0.000 claims abstract description 23
- 238000001035 drying Methods 0.000 claims abstract description 22
- 239000005955 Ferric phosphate Substances 0.000 claims abstract description 21
- 229940032958 ferric phosphate Drugs 0.000 claims abstract description 21
- 229910000399 iron(III) phosphate Inorganic materials 0.000 claims abstract description 21
- 230000003750 conditioning effect Effects 0.000 claims abstract description 18
- 238000000926 separation method Methods 0.000 claims abstract description 17
- 230000001143 conditioned effect Effects 0.000 claims abstract description 7
- 238000005119 centrifugation Methods 0.000 claims abstract description 6
- 238000005496 tempering Methods 0.000 claims description 61
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 claims description 22
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 claims description 22
- 235000019837 monoammonium phosphate Nutrition 0.000 claims description 22
- 239000006012 monoammonium phosphate Substances 0.000 claims description 22
- 238000002360 preparation method Methods 0.000 claims description 19
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 claims description 18
- 229910052921 ammonium sulfate Inorganic materials 0.000 claims description 18
- 235000011130 ammonium sulphate Nutrition 0.000 claims description 18
- 238000004519 manufacturing process Methods 0.000 claims description 11
- 229910000402 monopotassium phosphate Inorganic materials 0.000 claims description 11
- 235000019796 monopotassium phosphate Nutrition 0.000 claims description 11
- 150000001875 compounds Chemical class 0.000 claims description 10
- 239000011259 mixed solution Substances 0.000 claims description 10
- PJNZPQUBCPKICU-UHFFFAOYSA-N phosphoric acid;potassium Chemical compound [K].OP(O)(O)=O PJNZPQUBCPKICU-UHFFFAOYSA-N 0.000 claims description 10
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 claims description 8
- 239000005696 Diammonium phosphate Substances 0.000 claims description 7
- 229910000388 diammonium phosphate Inorganic materials 0.000 claims description 7
- 235000019838 diammonium phosphate Nutrition 0.000 claims description 7
- 238000001914 filtration Methods 0.000 claims description 7
- 239000000243 solution Substances 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 5
- 238000007602 hot air drying Methods 0.000 claims description 4
- 239000007787 solid Substances 0.000 claims 1
- 239000000126 substance Substances 0.000 abstract description 7
- 238000011084 recovery Methods 0.000 abstract description 6
- 239000007789 gas Substances 0.000 description 71
- 239000000047 product Substances 0.000 description 26
- 239000006096 absorbing agent Substances 0.000 description 15
- 238000006386 neutralization reaction Methods 0.000 description 11
- 229910021645 metal ion Inorganic materials 0.000 description 10
- 239000006200 vaporizer Substances 0.000 description 10
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 8
- 239000002351 wastewater Substances 0.000 description 8
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 7
- 229910019142 PO4 Inorganic materials 0.000 description 7
- -1 ammonium ions Chemical class 0.000 description 7
- 229910052739 hydrogen Inorganic materials 0.000 description 7
- 239000001257 hydrogen Substances 0.000 description 7
- 150000002500 ions Chemical class 0.000 description 7
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 7
- 239000010452 phosphate Substances 0.000 description 7
- 238000010586 diagram Methods 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000005507 spraying Methods 0.000 description 5
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 4
- 229910052757 nitrogen Inorganic materials 0.000 description 4
- 229910052698 phosphorus Inorganic materials 0.000 description 4
- 239000010935 stainless steel Substances 0.000 description 4
- 238000003860 storage Methods 0.000 description 4
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 3
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- 235000011941 Tilia x europaea Nutrition 0.000 description 3
- 239000004571 lime Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000010413 mother solution Substances 0.000 description 3
- 239000002244 precipitate Substances 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- 229910052567 struvite Inorganic materials 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 230000008016 vaporization Effects 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- MXZRMHIULZDAKC-UHFFFAOYSA-L ammonium magnesium phosphate Chemical compound [NH4+].[Mg+2].[O-]P([O-])([O-])=O MXZRMHIULZDAKC-UHFFFAOYSA-L 0.000 description 2
- 239000010405 anode material Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000011552 falling film Substances 0.000 description 2
- 239000000706 filtrate Substances 0.000 description 2
- 159000000003 magnesium salts Chemical class 0.000 description 2
- 239000012528 membrane Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 235000019738 Limestone Nutrition 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 229910001069 Ti alloy Inorganic materials 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 1
- CKMXBZGNNVIXHC-UHFFFAOYSA-L ammonium magnesium phosphate hexahydrate Chemical compound [NH4+].O.O.O.O.O.O.[Mg+2].[O-]P([O-])([O-])=O CKMXBZGNNVIXHC-UHFFFAOYSA-L 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 239000011790 ferrous sulphate Substances 0.000 description 1
- 235000003891 ferrous sulphate Nutrition 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 239000010842 industrial wastewater Substances 0.000 description 1
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 description 1
- 229910000359 iron(II) sulfate Inorganic materials 0.000 description 1
- 239000006028 limestone Substances 0.000 description 1
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 description 1
- 239000000347 magnesium hydroxide Substances 0.000 description 1
- 229910001862 magnesium hydroxide Inorganic materials 0.000 description 1
- 239000000395 magnesium oxide Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- GNSKLFRGEWLPPA-UHFFFAOYSA-M potassium dihydrogen phosphate Chemical compound [K+].OP(O)([O-])=O GNSKLFRGEWLPPA-UHFFFAOYSA-M 0.000 description 1
- LWIHDJKSTIGBAC-UHFFFAOYSA-K potassium phosphate Substances [K+].[K+].[K+].[O-]P([O-])([O-])=O LWIHDJKSTIGBAC-UHFFFAOYSA-K 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 239000012265 solid product Substances 0.000 description 1
- 229910001256 stainless steel alloy Inorganic materials 0.000 description 1
- 239000011232 storage material Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 239000006228 supernatant Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05B—PHOSPHATIC FERTILISERS
- C05B7/00—Fertilisers based essentially on alkali or ammonium orthophosphates
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Fertilizers (AREA)
Abstract
The invention provides a method and a system for treating ferric phosphate mother liquor and washing water, wherein the method comprises the following steps: s110, absorbing gas ammonia by using mother liquor to be treated to obtain process liquor, absorbing gas ammonia by using washing water to be treated to obtain ammonia absorption liquor, and absorbing gas ammonia by using process water to obtain ammonia water; wherein, the gas ammonia is generated by gasifying liquid ammonia by heat released by the mother liquor in the process of absorbing the gas ammonia; s120, conditioning the process liquid and the ammonia absorption liquid by using ammonia water; s130, performing one or more operations of evaporation concentration, centrifugation, solid-liquid separation, drying and cooling crystallization on the conditioned process liquid and the ammonia absorption liquid to obtain the product chemical fertilizer. The treatment water amount of subsequent evaporative crystallization can be reduced by using the gas ammonia; and the mother liquor after absorbing gas ammonia is cooled by circulating water and liquid ammonia gasification in sequence, the consumption of the circulating water is reduced by fully utilizing the heat absorption of the liquid ammonia gasification, the concentration of the mother liquor and washing water is improved while the ammonia recovery rate is improved, and the evaporation crystallization treatment water amount is further reduced, so that the investment and operation cost for treating the mother liquor and the washing water can be reduced.
Description
Technical Field
The invention relates to the technical field of wastewater treatment in new energy industry, in particular to a method and a system for treating iron phosphate mother liquor and washing water.
Background
With the rapid development of new energy markets, the demand for power batteries, energy storage materials or equipment is increasing, and the demand for preparing precursor iron phosphate of lithium iron phosphate of battery anode materials is correspondingly increasing, at present, ferrous sulfate, monoammonium phosphate and hydrogen peroxide are generally used as raw materials, and the iron phosphate is prepared by the processes of oxidation, synthesis, filtration, sintering, washing and the like, and the synthesis mother liquor and the washing water in the preparation process contain ammonium ions, metal ions and sulfate ions (SO) with different concentrations 4 2- ) Phosphate (hydrogen) ion (H) 2 PO 4 - ) If the high-salt inorganic wastewater is directly discharged, the discharge standard of the industrial wastewater is not met, and the surrounding environment is seriously polluted and damaged, so that the wastewater needs to be treated for recycling or meeting the discharge standard.
The iron phosphate is mainly used for producing the anode material lithium iron phosphate and is compounded by an iron phosphate precursor and battery-grade lithium hydroxide, and the reaction equation is as follows:
2FePO 4 +2LiOH+C→2LiFePO 4 +H 2 O+CO。
at present, two methods for producing iron phosphate exist, one is to use phosphoric acid and ferric salt for reaction, and the other is to recover lithium iron phosphate batteries. Both of the above iron phosphate treatment methods produce iron phosphate wastewater.
The current mainstream methods for the wastewater in the iron phosphate production comprise a lime precipitation method, a magnesium salt treatment method and a membrane treatment method:
1) Lime precipitation process
The method comprises the steps of adding a large amount of limestone and lime into wastewater, recovering gas ammonia without considering the standard exceeding of total salt, and directly discharging supernatant, and can generate a large amount of sludge which is difficult to treat without considering the discharge and disposal of salt.
2) Stripping of high concentration ammonia nitrogen and precipitation of magnesium ammonium phosphate
Adding magnesium oxide and magnesium hydroxide into the wastewater to generate magnesium ammonium phosphate (struvite); and then the residual ammonia/ammonium salt gas is stripped and sulfuric acid is absorbed to generate ammonium sulfate, but the method has long process flow, needs to consume a large amount of magnesium salt and steam, has high treatment cost and is difficult to discharge the waste water after reaching the standard.
3) Membrane process and multi-effect evaporation combined process
The ammonium sulfate and monoammonium phosphate fertilizer are generated, and the distilled water can be recycled, but the process is complex and the investment cost is high.
Further, the chinese patent application publication No. CN114105392A discloses a method for treating iron phosphate wastewater, comprising:
s1, pretreating a ferric phosphate mother solution to obtain a mother solution clarified filtrate, adding ammonia water to adjust the pH of the mother solution in the ferric phosphate production process to 7-8, pretreating ferric phosphate washing water to obtain concentrated water A, and adding ammonia water to adjust the pH of the washing water in the ferric phosphate production process to 7-8 before concentration;
s2, mixing the mother liquor clear filtrate with concentrated water A, and then evaporating and concentrating to obtain concentrated water B;
s3, centrifuging the concentrated water B, cooling and crystallizing to obtain a solid product, and drying to obtain fertilizer products of ammonium sulfate, ammonium hydrogen phosphate and magnesium sulfate.
This method has the following problems:
1) The demand for ammonia water is large, and the transportation and storage costs are high.
2) The ammonia water is used for tempering, so that the treatment capacity of mother liquor and washing water is increased by 5-20%, and the investment and operation cost of subsequent MVR evaporation crystallization are increased.
Therefore, how to reduce the treatment cost of the mother liquor and the washing water in the production process of the iron phosphate becomes a technical problem to be solved urgently.
Disclosure of Invention
Aiming at the technical problems that the treatment cost of mother liquor and washing water in the production process of the iron phosphate is high or the treatment is incomplete.
The invention provides a method for treating ferric phosphate mother liquor and washing water, which comprises the following steps:
s110, absorbing gas ammonia by using mother liquor to be treated to obtain process liquor, absorbing gas ammonia by using washing water to be treated to obtain ammonia absorbing liquor, and absorbing gas ammonia by using process water to obtain ammonia water; wherein, the gas ammonia is generated by gasifying liquid ammonia by heat released by the mother liquor in the process of absorbing the gas ammonia;
s120, conditioning the process liquid and the ammonia absorption liquid by using ammonia water;
s130, performing one or more operations of evaporation concentration, centrifugation, solid-liquid separation, drying and cooling crystallization on the conditioned process liquid and the ammonia absorption liquid to obtain the product chemical fertilizer.
Preferably, in S110, the method further comprises cooling the process liquid by using the circulating water and liquid ammonia gasification, and the ratio of the heat transfer amount of the circulating water and the gasification of the liquid ammonia is 1 (2-10).
Preferably, in S110, the mass ratio of the mother liquor, the washing water and the process water to absorb the ammonia gas is 1 (0.10-0.35) to (0.15-0.50).
Preferably, in S110, the concentration of the ammonia water obtained after the process water absorbs the gaseous ammonia is 17.7% to 22.3%.
Preferably, in S110, the mother liquor and the washing water are in a flowing state, wherein the flow rate of the mother liquor is 50-600m 3 The flow rate of washing water is 80-1200m 3 The volume ratio of the mother liquor to the washing water is 1 (1.3-2.5).
Preferably, in S120, the pH of the process liquid before tempering is 4.2-5.3, and the pH after tempering is 6.8-8.4; the pH value of the ammonia absorption liquid before tempering is 4.5-5.6, and the pH value after tempering is 7-8.8; the ratio of the process liquid to the ammonia absorption liquid for absorbing ammonia water is 1 (0.5-2.0).
Preferably, in S130, the product fertilizer comprises ammonium sulfate and monoammonium phosphate; wherein, the monoammonium phosphate is obtained by one or more operations of cooling crystallization, solid-liquid separation and drying of partial centrifugal mother liquor of the ammonium sulfate.
Preferably, after S130, the method further comprises: and S140, dissolving the monoammonium phosphate in water, and further reacting the monoammonium phosphate with ammonia water to obtain diammonium phosphate.
As a parallel scheme, the invention also provides a method for treating the ferric phosphate mother liquor and the washing water, which further comprises the following steps:
s210, absorbing gas ammonia by using mother liquor to be treated to obtain process liquor, absorbing gas ammonia by using washing water to be treated to obtain ammonia absorbing liquor, and absorbing gas ammonia by using process water to obtain ammonia water; wherein, the gas ammonia is generated by gasifying liquid ammonia by heat released by the mother liquor in the process of absorbing the gas ammonia;
s220, mixing the ammonia absorption liquid with process liquid after evaporation concentration operation including but not limited to, so as to obtain mixed liquid;
s230, tempering the mixed solution by using ammonia water and potassium dihydrogen phosphate;
s240, performing one or more operations of evaporation concentration and hot air drying on the tempered mixed solution to obtain the product compound fertilizer.
The invention also provides a treatment system of the ferric phosphate mother liquor and the washing water, which is applied to the treatment method and the parallel scheme of the ferric phosphate mother liquor and the washing water, and the system comprises the following components:
the mother liquor ammonia absorption cooling equipment is used for preparing process liquid by absorbing gas ammonia with mother liquor and cooling the process liquid; and
the washing water ammonia absorption equipment is used for preparing ammonia absorption liquid by washing water absorption gas ammonia;
the ammonia water preparation equipment is used for preparing ammonia water by absorbing gas ammonia with process water;
the liquid ammonia gasification equipment is used for gasifying liquid ammonia by utilizing heat released by absorbing gas ammonia by the mother liquor, and respectively provides gas ammonia for the mother liquor ammonia absorption cooling equipment, the washing water ammonia absorption equipment and the ammonia water preparation equipment through gas ammonia pipelines;
the conditioning equipment is respectively connected with the mother liquor ammonia absorption cooling equipment, the washing water ammonia absorption equipment and the ammonia water preparation and is used for conditioning the process liquid and the ammonia absorption liquid by using the ammonia water; or the ammonia water treatment system is respectively connected with the mother liquor ammonia absorption cooling equipment, the washing water ammonia absorption equipment and the ammonia water preparation and is used for tempering the mixed solution of the process liquid and the ammonia absorption liquid by using ammonia water and potassium dihydrogen phosphate;
and the fertilizer production equipment is connected with the conditioning equipment and is used for preparing a fertilizer product after one or more operations of filtering, evaporating and concentrating, centrifuging, solid-liquid separating, drying, cooling and crystallizing the conditioned process liquid and the ammonia absorption liquid.
In summary, according to the lithium iron phosphate mother liquor and the washing water treatment method and system provided by the invention, the liquid ammonia is gasified into gaseous ammonia by using the heat released by absorbing gaseous ammonia with the mother liquor, the process liquor is prepared by absorbing gaseous ammonia with the mother liquor, the ammonia absorption liquid is prepared by absorbing gaseous ammonia with the washing water, and the process liquor and the ammonia absorption liquid are subjected to quality adjustment by using ammonia water obtained by absorbing gaseous ammonia with the process water, and then the product chemical fertilizer or the product compound fertilizer is obtained through operations such as evaporation concentration, separation and drying.
Wherein, the use of the gas ammonia can reduce the transportation cost of the ammonia water and the water amount of subsequent evaporative crystallization treatment; furthermore, the mother liquor absorbs the gas ammonia and continuously emits heat to gasify the liquid ammonia, so that a liquid ammonia storage tank with large potential safety hazard is not needed, the mother liquor after absorbing the gas ammonia is cooled by circulating water and liquid ammonia gasification sequentially, the liquid ammonia gasification heat absorption can be fully utilized, the consumption of the circulating water is reduced, the concentration of the mother liquor and washing water is improved while the ammonia recovery rate is improved, the evaporation crystallization treatment water amount is further reduced, the mother liquor and the washing water are efficiently and inexpensively recovered into chemical fertilizers, and the investment and the operation cost for treating the mother liquor and the washing water are reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1: the embodiment of the invention provides a flow chart of a method for treating ferric phosphate mother liquor and washing water;
FIG. 2 is a schematic diagram: the process diagram of the treatment method of the ferric phosphate mother liquor and the washing water provided by the embodiment of the invention;
FIG. 3: the embodiment of the invention provides a flow chart of a method for treating ferric phosphate mother liquor and washing water;
FIG. 4: the embodiment of the invention provides a flow chart of a method for treating ferric phosphate mother liquor and washing water;
FIG. 5: the process diagram of the treatment method of the ferric phosphate mother liquor and the washing water provided by the embodiment of the invention;
FIG. 6: the embodiment of the invention provides an equipment diagram for producing a product, namely a chemical fertilizer, by using a treatment system of iron phosphate mother liquor and washing water;
FIG. 7 is a schematic view of: the embodiment of the invention provides a device diagram for producing a compound fertilizer by a treatment system of iron phosphate mother liquor and washing water.
Detailed Description
In order to make the above and other features and advantages of the present invention more apparent, the present invention is further described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are for purposes of illustration only and are not intended to be limiting.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the specific details need not be employed to practice the present invention. In other instances, well-known steps or operations are not described in detail to avoid obscuring the invention.
In order to reduce the treatment cost of the mother liquor and the washing water in the ferric phosphate production process, the invention provides a treatment method of ferric phosphate mother liquor and washing water, as shown in figure 1, the method comprises the following steps:
s110, absorbing gas ammonia by using mother liquor to be treated to obtain process liquor, absorbing gas ammonia by using washing water to be treated to obtain ammonia absorption liquor, and absorbing gas ammonia by using process water to obtain ammonia water; wherein, the gas ammonia is generated by gasifying liquid ammonia through heat released by the mother liquor in the process of absorbing the gas ammonia.
As shown in fig. 2, in the present application, the heat released by the liquid ammonia absorption mother liquor during the process of absorbing gaseous ammonia is gasified to generate gaseous ammonia, and the gaseous ammonia is respectively delivered to the mother liquor, the washing water and the process water through the gaseous ammonia pipeline. The mother liquor and the washing water are treated by utilizing the gas ammonia generated by gasifying the liquid ammonia without using ammonia water, so that the transportation cost and the treatment water amount of subsequent operations such as evaporation crystallization and the like can be reduced.
Specifically, the liquid ammonia gasification, mother liquor ammonia absorption and process liquid cooling equipment is integrated equipment, in the preferred scheme, the lower part is a liquid ammonia gasifier, gas ammonia obtained by liquid ammonia gasification is connected to the mother liquor ammonia absorber on the upper part through an internal pipeline to prepare process liquid, and then the process liquid is cooled through a middle circulating water cooler and the lower part liquid ammonia gasifier. Wherein, the temperature of the gas ammonia after the liquid ammonia gasification is-5 to 10 ℃, the pressure is 0.3 to 1.5MPa, and the gas ammonia can be directly sent into a washing water and process water ammonia absorption tower. In a preferred scheme, the process liquid is cooled by circulating water and gasified liquid ammonia, and the ratio of the heat transfer quantity of the two parts is 1 (2-10). Therefore, the amount of gas ammonia generated by gasifying the liquid ammonia is ensured, the heat absorption of gasifying the liquid ammonia is fully utilized, and the circulating water consumption of cooling process liquid is reduced. Furthermore, the circulating water and the liquid ammonia gasification two-stage cooling fully utilize the liquid ammonia gasification cold quantity, thereby removing heat in time, preventing ammonia from escaping, improving the recovery rate of ammonia and reducing the secondary pollution of ammonia.
In some preferred schemes, the mass ratio of the mother liquor, the washing water and the process water to absorb the ammonia gas is 1 (0.10-0.35) to (0.15-0.50). According to the mother liquor, the washing water component and the tempering requirement, the using amount of ammonia is accurately controlled, and the using amount of ammonia water is reduced as much as possible, so that the concentration of the process liquid can be improved, the processing amount of the process liquid can be reduced, and the investment and the operation cost of subsequent MVR evaporation crystallization can also be reduced.
In other preferable schemes, the concentration of the ammonia water obtained after the process water absorbs the gas ammonia is 17.7-22.3%. The treatment capacity of mother liquor and washing water can be ensured by accurately controlling the concentration of ammonia water, the subsequent adjustment of the pH of the process liquid and the ammonia absorption liquid is facilitated, and the treatment capacity of the process liquid and the ammonia absorption liquid after tempering can be reduced as much as possible.
In a more preferable scheme, the mother liquor and the washing water are in a flowing state, wherein the flow rate of the mother liquor is 50-600m 3 The flow rate of washing water is 80-1200m 3 H, the volume ratio of the mother liquor to the washing water is 1 (1.3-2.5), and the washing water is accurately controlledThe flow of the mother liquor and the washing water and the volume ratio of the mother liquor to the washing water can fully ensure the efficiency of the mother liquor and the washing water.
In some more preferable schemes, the washing water and the process water absorb ammonia gas by adopting an absorption tower spraying mode, the liquid-gas ratio in the absorption tower for preparing ammonia absorption liquid by washing water is 0.18-0.35L/L, the spraying layer number is at least 2, the liquid-gas ratio in the absorption tower for preparing ammonia water by process water is 0.02-0.1L/L, and the spraying layer number is at least 2.
And S120, conditioning the process liquid and the ammonia absorption liquid by using ammonia water.
Specifically, the pH value of the process liquid before tempering is 4.2-5.3, and the pH value after tempering is 6.8-8.4; the pH value of the ammonia absorption liquid before tempering is 4.5-5.6, and the pH value after tempering is 7-8.8; through the two-stage pH control, not only can the precipitation of a large amount of metal ions when absorbing gas ammonia be prevented from influencing the absorption effect, but also the precipitation amount of the metal ions in the two stages can be reasonably distributed, so that the metal ions are more thoroughly precipitated. Furthermore, in the tempering process, the ratio of the process liquid to the ammonia absorption liquid to absorb ammonia water is 1 (0.5-2.0), the usage amount of the ammonia water is accurately controlled, and the treatment amount of the process liquid and the ammonia absorption liquid after the tempering is reduced as much as possible under the condition of meeting the tempering requirement.
After tempering, the concentration of ammonium ions in the process liquid is 15-30g/L, the concentration of sulfate ions is 50-100g/L, the concentration of phosphate (hydrogen) ions is 0.5-2g/L, and the concentration of metal ions is 1.1-4g/L; the concentration of ammonium ions in the ammonia absorption liquid is 5-10g/L, the concentration of sulfate ions is 15-40g/L, and the concentration of phosphate (hydrogen) ions is 1.5-5g/L; the concentration of metal ions is 0.25-1g/L.
S130, performing one or more operations of evaporation concentration, centrifugation, solid-liquid separation, drying and cooling crystallization on the conditioned process liquid and the ammonia absorption liquid to obtain the product chemical fertilizer.
Specifically, the fertilizer product comprises ammonium sulfate and monoammonium phosphate; the process liquid after the tempering and the centrifugal liquid obtained by evaporating and crystallizing the ammonia absorption liquid are separated by solid-liquid separation equipment and then dried by drying equipment to obtain the product ammonium sulfate; wherein, the nitrogen content in the ammonium sulfate is more than or equal to 20 percent, and the sulfur content is more than or equal to 23 percent. Further, cooling, crystallizing, carrying out solid-liquid separation and drying on part of the ammonium sulfate solid-liquid separation mother liquor by using cooling crystallization equipment to obtain the product monoammonium phosphate.
As shown in fig. 3, after S130, the method further includes: and S140, dissolving the monoammonium phosphate in water, and further reacting with ammonia water to obtain diammonium phosphate.
After the monoammonium phosphate is prepared, the monoammonium phosphate can be reused for preparing the iron phosphate according to the requirement, or further reacted with ammonia water to be processed into diammonium phosphate.
As a parallel scheme of the present application, the present application further provides a method for treating iron phosphate mother liquor and washing water, as shown in fig. 4, the method further includes:
s210, absorbing gas ammonia by using mother liquor to be treated to obtain process liquor, absorbing gas ammonia by using washing water to be treated to obtain ammonia absorbing liquor, and absorbing gas ammonia by using process water to obtain ammonia water;
wherein, the gas ammonia is generated by gasifying liquid ammonia by heat released by the mother liquor in the process of absorbing the gas ammonia;
as shown in fig. 5, in the present application, the heat released by the liquid ammonia absorption mother liquor during the process of absorbing gaseous ammonia is gasified to generate gaseous ammonia, and the gaseous ammonia is respectively delivered to the mother liquor, the washing water and the process water through the gaseous ammonia pipeline. The mother liquor and the washing water are treated by the gas ammonia generated by gasifying the liquid ammonia without using ammonia water, so that the transportation cost and the treatment water amount of subsequent operations such as evaporation crystallization and the like can be reduced.
Specifically, the liquid ammonia gasification, mother liquor ammonia absorption and process liquid cooling equipment is integrated equipment, in the preferred scheme, the lower part is a liquid ammonia gasifier, gas ammonia obtained by liquid ammonia gasification is connected to the mother liquor ammonia absorber on the upper part through an internal pipeline to prepare process liquid, and then the process liquid is cooled through a middle circulating water cooler and the lower part liquid ammonia gasifier. Wherein, the temperature of the gas ammonia after the liquid ammonia is gasified is-5 to 10 ℃, the pressure is 0.3 to 1.5MPa, and the gas ammonia can be directly sent into a washing water and process water ammonia absorption tower. In the preferred scheme, the process liquid is cooled by the gasification of the circulating water and the liquid ammonia, and the ratio of the heat transfer of the two parts is 1 (2-10). Therefore, the amount of gas ammonia generated by gasifying the liquid ammonia is ensured, the heat absorption of gasifying the liquid ammonia is fully utilized, and the circulating water consumption of cooling process liquid is reduced. Furthermore, the circulating water and the liquid ammonia gasification two-stage cooling fully utilize the gasification cold quantity of the liquid ammonia, thereby being capable of removing heat in time, preventing ammonia from escaping, improving the recovery rate of ammonia and reducing the secondary pollution of ammonia.
In some preferred schemes, the mass ratio of the mother liquor, the washing water and the process water to absorb the ammonia gas is 1 (0.1-0.35) to (0.15-0.5). According to the mother liquor, the washing water component and the tempering requirement, the using amount of ammonia is accurately controlled, and the using amount of ammonia water is reduced as much as possible, so that the concentration of the process liquid can be improved, the processing amount of the process liquid can be reduced, and the investment and the operation cost of subsequent MVR evaporation crystallization can also be reduced.
In other preferable schemes, the concentration of the ammonia water obtained after the process water absorbs the gas ammonia is 17.7-22.3%. The treatment capacity of mother liquor and washing water can be ensured by accurately controlling the concentration of ammonia water, the subsequent adjustment of the pH of the process liquid and the ammonia absorption liquid is facilitated, and the treatment capacity of the process liquid and the ammonia absorption liquid after tempering can be reduced as much as possible.
In a more preferable scheme, the mother liquor and the washing water are in a flowing state, wherein the flow rate of the mother liquor is 50-600m 3 The flow rate of washing water is 80-1200m 3 The volume ratio of the mother liquor to the washing water is 1 (1.3-2.5), and the efficiency of treating the mother liquor and the washing water can be fully ensured by accurately controlling the flow rates of the mother liquor and the washing water and the volume ratio of the mother liquor to the washing water.
S220, mixing the ammonia absorption liquid with process liquid after evaporation concentration operation including but not limited to, so as to obtain mixed liquid;
s230, tempering the mixed solution by using ammonia water and potassium dihydrogen phosphate;
s240, performing one or more operations of evaporation concentration and hot air drying on the tempered mixed solution to obtain the product compound fertilizer.
Specifically, in the scheme, ammonia water is not used for tempering the ammonia absorption liquid, the ammonia absorption liquid is directly mixed with the process liquid after being concentrated, the mixed liquid is mixed and tempered by using ammonia water and potassium dihydrogen phosphate, and then the mixed liquid is further concentrated and then is subjected to hot air drying to obtain the product compound fertilizer. N and P in compound fertilizer 2 O 5 And K 2 The content of O is 40-50%, wherein, the content of N is more than or equal to 15%, P 2 O 5 The content is more than or equal to 16 percent,K 2 the content of O is more than or equal to 9 percent.
In summary, the method provided by the invention has the following advantages:
1) The use of the gas ammonia reduces the transportation cost of the ammonia water and the water amount of evaporative crystallization treatment, improves the concentration of mother liquor and washing water while improving the recovery rate of the ammonia, and reduces the investment and the operation cost of evaporative crystallization.
2) Liquid ammonia gasification heat absorption is fully utilized, and circulating water consumption is reduced.
3) Liquid ammonia is directly gasified and absorbed by process water/washing water/mother liquor, and a liquid ammonia storage tank with large potential safety hazard is not required to be matched.
4) The temperature of the process liquid can be reduced to 20-30 ℃ after the two-stage cooling of the circulating water and the liquid ammonia gasification, the cold energy of the liquid ammonia gasification is fully utilized, the heat is removed in time, the ammonia escape is prevented, the ammonia recovery rate is improved, and the secondary pollution is reduced.
5) The ammonia proportion in each step, the pH after ammonia use, the liquid-gas ratio of the absorption tower and other parameters are strictly controlled, the quality of ammonium sulfate and monoammonium phosphate products is guaranteed, the mother liquor and the washing water are recycled into chemical fertilizers with high efficiency and low cost, and the monoammonium phosphate can be reused for preparing the ferric phosphate or further processed into diammonium phosphate products as required.
6) The investment and the operation cost are reduced, the occupied area is reduced, and the operation stability is improved.
7) The mother liquor and the washing water can be independently modified or combined for modification, and the N and P can be produced by combining and modifying with ammonia water and potassium dihydrogen phosphate 2 O 5 And K 2 The total content of O is 40-50%, wherein, the content of N is more than or equal to 15%, and P is 2 O 5 Content is more than or equal to 16 percent, K 2 The O content is more than or equal to 9 percent, the added value of the product is improved, the investment and the operation cost are reduced, and the product structure is improved.
In order to demonstrate the advantages of the method provided by the present invention, reference will now be made to specific examples.
Example one
Liquid ammonia is gasified into gas ammonia by using the heat of the mother liquor for absorbing ammonia gas, the temperature of the gas ammonia after the liquid ammonia is gasified is 0 ℃, the pressure is 1MPa, the gasified liquid ammonia is respectively absorbed by the mother liquor, washing water and process water, and the absorption mass ratio is 1.25.
The temperature of the mother liquor after ammonia gas absorption is 60 ℃, the mother liquor after ammonia gas absorption is gasified by circulating water and liquid ammonia and then cooled, and the heat ratio of the two parts is 1; the temperature of the process liquid after cooling is 25 ℃.
The concentration of the ammonia water obtained after the process water absorbs the gas ammonia is 20 percent.
Ammonia water is used for tempering the process liquid, the pH value before tempering is 4.5, and the pH value after tempering is 7;
ammonia water is used for tempering the ammonia absorption liquid, the pH value before tempering is 4.8, and the pH value after tempering is 7.3;
wherein, the ratio of the process liquid to the ammonia absorption liquid to absorb ammonia water is 1.35.
After tempering, the concentration of ammonium ions in the process liquid is 22g/L, the concentration of sulfate ions is 65g/L, the concentration of phosphate (hydrogen) ions is 1.1g/L, and the concentration of metal ions is 1.1g/L;
the concentration of ammonium ions in the ammonia absorption liquid is 7g/L, the concentration of sulfate ions is 20g/L, and the concentration of phosphate (hydrogen) ions is 3g/L; the concentration of metal ions was 0.3g/L.
Separating the process liquid after tempering and the centrifugate evaporated and crystallized from the ammonia absorption liquid by solid-liquid separation equipment, and drying by drying equipment to obtain a product ammonium sulfate; and cooling, crystallizing, carrying out solid-liquid separation and drying on part of the ammonium sulfate solid-liquid separation mother liquor by using cooling crystallization equipment to obtain the product monoammonium phosphate.
Wherein the mother liquid flow rate is 180m 3 Flow rate of washing water is 360m 3 H; the consumption of liquid ammonia is 1t/h, the yield of the product ammonium sulfate is 20t/h, and the yield of the product monoammonium phosphate is 0.5t/h.
Example two
Liquid ammonia is gasified into gas ammonia by using heat of ammonia absorbed by mother liquor, the temperature of the gas ammonia after the liquid ammonia is gasified is 3 ℃, the pressure is 1.3MPa, the gasified liquid ammonia is respectively absorbed by the mother liquor, washing water and process water, and the absorption mass ratio is 1.3.
The temperature of the mother liquor after ammonia gas absorption is 75 ℃, the mother liquor after ammonia gas absorption is gasified by circulating water and liquid ammonia and then cooled, and the heat ratio of the two parts is 1; the temperature of the process liquid after cooling is 28 ℃.
The concentration of the ammonia water obtained after the process water absorbs the gas ammonia is 21 percent.
Ammonia water is used for tempering the process liquid, the pH value before tempering is 4.9, and the pH value after tempering is 7.6;
ammonia water is used for tempering the ammonia absorption liquid, the pH value before tempering is 5.2, and the pH value after tempering is 8;
wherein, the ratio of the process liquid to the ammonia absorption liquid to absorb ammonia water is 1.35.
After quenching and tempering, the concentration of ammonium ions in the process liquid is 27g/L, the concentration of sulfate ions is 74g/L, the concentration of phosphate (hydrogen) ions is 1.75g/L, and the concentration of metal ions is 1.6g/L;
the concentration of ammonium ions in the ammonia absorption liquid is 9g/L, the concentration of sulfate ions is 27g/L, and the concentration of phosphate (hydrogen) ions is 4.2g/L; the metal ion concentration was 0.6g/L.
Separating the process liquid after tempering and the centrifugate evaporated and crystallized from the ammonia absorption liquid by solid-liquid separation equipment, and drying by drying equipment to obtain a product ammonium sulfate; and (3) cooling, crystallizing, carrying out solid-liquid separation and drying on part of ammonium sulfate solid-liquid separation mother liquor by using cooling crystallization equipment to obtain a product monoammonium phosphate, further dissolving the obtained monoammonium phosphate in water, further reacting the obtained monoammonium phosphate with ammonia water, and then cooling, crystallizing, carrying out solid-liquid separation and drying by using cooling crystallization equipment to obtain diammonium phosphate.
Wherein the mother liquid flow rate is 180m 3 Flow rate of washing water is 360m 3 H; the consumption of liquid ammonia is 1.5t/h, the yield of ammonium sulfate is 25t/h, and the yield of diammonium phosphate is 2t/h.
EXAMPLE III
The embodiment is a parallel scheme of the embodiment 1, ammonia water is not used for tempering the ammonia absorption liquid 2, the ammonia absorption liquid 2 is directly concentrated and then mixed with the process liquid, ammonia water and potassium dihydrogen phosphate are used for mixing and tempering to obtain a mixed liquid, and the mixed liquid is further concentrated and then dried by hot air to obtain a product compound fertilizer.
Wherein the mother liquid flow rate is 180m 3 Flow rate of washing water is 360m 3 H; the consumption of liquid ammonia is 1.6t/h, the consumption of monopotassium phosphate is 12t/h, and the yield of the compound fertilizer is 40t/h. N and P in compound fertilizer 2 O 5 And K 2 The total content of O is 47.5%, the content of N is 19%, P 2 O 5 Content 21%, K 2 The O content was 11%.
The application also provides a processing system of ferric phosphate mother liquor and washing water, is applied to the processing method of the ferric phosphate mother liquor and washing water of this application, and this system includes:
the mother liquor ammonia absorption cooling equipment is used for preparing the process liquid by absorbing gas ammonia by the mother liquor and cooling the process liquid; and
the washing water ammonia absorption equipment is used for preparing ammonia absorption liquid by absorbing ammonia gas through washing water;
the ammonia water preparation equipment is used for preparing ammonia water by absorbing gas ammonia with process water;
the liquid ammonia gasification equipment is used for gasifying liquid ammonia by utilizing heat released by absorbing gas ammonia by the mother liquor, and respectively provides gas ammonia for the mother liquor ammonia absorption cooling equipment, the washing water ammonia absorption equipment and the ammonia water preparation equipment through gas ammonia pipelines;
the conditioning equipment is respectively connected with the mother liquor ammonia absorption cooling equipment, the washing water ammonia absorption equipment and the ammonia water preparation and is used for conditioning the process liquid and the ammonia absorption liquid by using the ammonia water; or the ammonia water treatment system is respectively connected with the mother liquor ammonia absorption cooling equipment, the washing water ammonia absorption equipment and the ammonia water preparation and is used for tempering the mixed solution of the process liquid and the ammonia absorption liquid by using ammonia water and potassium dihydrogen phosphate;
and the fertilizer production equipment is connected with the conditioning equipment and is used for preparing a fertilizer product after one or more operations of filtering, evaporating and concentrating, centrifuging, solid-liquid separating, drying, cooling and crystallizing the conditioned process liquid and the ammonia absorption liquid.
Specifically, as shown in fig. 6 and 7, the liquid ammonia vaporizer, the mother liquid ammonia absorber, and the process liquid cooler are integrated, and the liquid ammonia vaporizer is disposed at the lower portion, and gaseous ammonia obtained by vaporizing liquid ammonia is connected to the upper mother liquid ammonia absorber through an internal pipe, and is then cooled by the middle circulating water cooler and the lower liquid ammonia vaporizer, and then connected to the process liquid quality adjusting apparatus. Therefore, the liquid ammonia can be gasified after being directly unloaded, and a liquid ammonia storage tank is not required to be arranged. Wherein, liquid ammonia vaporizer is liquid ammonia gasification equipment, and mother liquor ammonia absorption cooling arrangement includes mother liquor ammonia absorber and circulating water cooler. In fig. 6, the conditioning equipment comprises a process liquid conditioning tank and a conditioning tank, and the fertilizer production equipment comprises a filter 1, a filter 2, an evaporator, a centrifuge and a dryer; in fig. 7, the conditioning equipment comprises a neutralization reactor and a preparation tank, and the fertilizer production equipment comprises a filter, an evaporator, a centrifuge and a dryer.
The ammonia absorption equipment for washing water comprises an absorption tower 1, the ammonia water preparation equipment comprises an absorption tower 2, the liquid-gas ratio in the absorption tower 1 is 0.18-0.35L/L, the number of spraying layers is at least 2, the liquid-gas ratio in the absorption tower 2 is 0.02-0.1L/L, and the number of spraying layers is at least 2.
The evaporation concentration equipment comprises 4-5-effect steam evaporation equipment, 3-effect MVR evaporation equipment and 3-effect MVR evaporation equipment; wherein, the temperature rise of the steam compressor is not less than 16 ℃, and the 3-effect MVR evaporation equipment is preferably double-effect falling film (rising film) evaporation equipment and single-effect forced circulation equipment.
Furthermore, in order to prevent corrosion of the equipment, the evaporation equipment is made of 316L stainless steel, 2205 stainless steel, 2507 stainless steel, titanium or nickel alloy. The double-effect falling film evaporation equipment is preferably made of 2205 stainless steel, and the single-effect forced circulation evaporation equipment is made of TA2 titanium.
In order to implement a specific embodiment of the method of the present invention, a corresponding system embodiment is provided below.
Example four
In this example, the iron phosphate mother liquor and the washing water treatment method of the first and second examples can be realized.
Specifically, as shown in fig. 6, the system for processing iron phosphate mother liquor and washing water provided in this embodiment includes: the device comprises a liquid ammonia gasifier, a mother liquor ammonia absorber, a process liquid cooler, an absorption tower 1, an absorption tower 2, washing water concentration equipment, a conditioning tank, a process liquid conditioning tank, a filter 1, a filter 2, an evaporator, a centrifugal machine and a dryer.
The liquid ammonia vaporizer, the mother liquid ammonia absorber and the process liquid cooler are integrated equipment, the liquid ammonia vaporizer is arranged on the lower portion, gas ammonia obtained by liquid ammonia vaporization is connected to the upper mother liquid ammonia absorber through an internal pipeline, and then is cooled through the middle circulating water cooler and the lower liquid ammonia vaporizer and then is connected with the process liquid tempering tank.
The branch of the gas ammonia pipeline of the liquid ammonia gasifier is also connected with the absorption tower 1 and the absorption tower 2 to provide gas ammonia for the absorption tower 1 and the absorption tower 2; wherein, the absorption tower 1 is used for preparing ammonia water by absorbing gas ammonia with process water, and the absorption tower 2 is used for preparing ammonia absorption liquid by absorbing gas ammonia with washing water.
The washing water concentration equipment is respectively connected with the absorption tower 2 and the tempering tank so as to concentrate the ammonia absorption liquid prepared in the absorption tower 2 and then convey the ammonia absorption liquid to the tempering tank.
The process liquid tempering tank is connected with the mother liquid ammonia absorber and is used for receiving the process liquid prepared in the mother liquid ammonia absorber.
The absorption tower 1 is respectively connected with the tempering tank and the process liquid tempering tank so as to utilize the ammonia water prepared in the absorption tower 1 to temper the ammonia absorption liquid in the tempering tank and the process liquid in the process liquid tempering tank.
The filter 1 is connected with the tempering tank and is used for filtering metal precipitates precipitated in the tempering tank and conveying the filtered ammonia absorption liquid to the evaporator.
The filter 2 is connected with the process liquid tempering tank and is used for filtering metal precipitates separated out from the process liquid tempering tank and conveying the filtered process liquid to the evaporator.
The evaporator is also connected with the centrifuge and the dryer in sequence and is used for carrying out operations such as evaporation crystallization, centrifugation, drying and the like on the ammonia absorption liquid and the process liquid.
EXAMPLE five
In this embodiment, the iron phosphate mother liquor and the washing water treatment method of the third embodiment can be realized.
Specifically, as shown in fig. 7, the system for processing iron phosphate mother liquor and washing water provided in this embodiment includes: the system comprises a liquid ammonia gasifier, a mother liquid ammonia absorber, a process liquid cooler, an absorption tower 1, an absorption tower 2, washing water concentration equipment, a neutralization reactor, a preparation tank, a filter, an evaporator, a centrifugal machine and a dryer.
The liquid ammonia vaporizer, the mother liquid ammonia absorber and the process liquid cooler are integrated equipment, the liquid ammonia vaporizer is arranged on the lower portion, gas ammonia obtained by vaporizing liquid ammonia is connected to the upper mother liquid ammonia absorber through an internal pipeline, and then is cooled through the middle circulating water cooler and the lower liquid ammonia vaporizer and then is connected with the neutralization reactor.
The branch of the gas ammonia pipeline of the liquid ammonia gasifier is also connected with the absorption tower 1 and the absorption tower 2 to provide gas ammonia for the absorption tower 1 and the absorption tower 2; wherein, the absorption tower 1 is used for preparing ammonia water by absorbing gas ammonia with process water, and the absorption tower 2 is used for preparing ammonia absorption liquid by absorbing gas ammonia with washing water.
The washing water concentration device is respectively connected with the absorption tower 2 and the neutralization reactor, so that the ammonia absorption liquid prepared in the absorption tower 2 is concentrated and then is conveyed to the neutralization reactor.
The neutralization reactor is also connected with the mother liquor ammonia absorber and is used for receiving the process liquid prepared in the mother liquor ammonia absorber.
The absorption tower 1 is respectively connected with the neutralization reactor and the preparation tank, and the preparation tank is also connected with the neutralization reactor, so that the ammonia water prepared in the absorption tower 1 and the potassium dihydrogen phosphate prepared in the preparation tank are utilized to adjust and temper the mixed solution of the process liquid and the ammonia absorption liquid in the neutralization reactor.
The filter is connected with the neutralization reactor and is used for filtering metal precipitates separated out from the neutralization reactor and conveying the filtered mixed liquid to the evaporator.
The evaporator is also connected with the centrifuge and the dryer in sequence and is used for carrying out operations such as evaporative crystallization, centrifugation, drying and the like on the mixed liquid.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A method for treating ferric phosphate mother liquor and washing water is characterized by comprising the following steps:
s110, absorbing gas ammonia by using mother liquor to be treated to obtain process liquor, absorbing gas ammonia by using washing water to be treated to obtain ammonia absorption liquor, and absorbing gas ammonia by using process water to obtain ammonia water;
wherein the gas ammonia is generated by gasifying liquid ammonia by the heat released by the mother liquor in the process of absorbing the gas ammonia;
s120, tempering the process liquid and the ammonia absorption liquid by using the ammonia water;
s130, performing one or more operations of evaporation concentration, centrifugation, solid-liquid separation, drying and cooling crystallization on the modified process liquid and the modified ammonia absorption liquid to obtain a fertilizer product.
2. The method for treating iron phosphate mother liquor and washing water according to claim 1,
s110, cooling the process liquid by utilizing circulating water and liquid ammonia gasification, wherein the ratio of the circulating water to the heat transferred by the liquid ammonia gasification is 1 (2-10).
3. The method for treating iron phosphate mother liquor and washing water according to claim 1,
in S110, the mass ratio of the mother liquor to the washing water to the process water to absorb the ammonia gas is 1 (0.10-0.35) to 0.15-0.50.
4. The method for treating iron phosphate mother liquor and washing water according to claim 1,
in S110, the concentration of the ammonia water obtained after the process water absorbs the gas ammonia is 17.7% -22.3%.
5. The method for treating iron phosphate mother liquor and washing water according to claim 1,
in S110, the mother liquor and the washing water are in a flowing state, wherein the flow rate of the mother liquor is 50-600m 3 The flow rate of the washing water is 80-1200m 3 The volume ratio of the mother liquor to the washing water is 1 (1.3-2.5).
6. The method for treating iron phosphate mother liquor and washing water according to claim 1,
in S120, the pH value of the process liquid before tempering is 4.2-5.3, and the pH value after tempering is 6.8-8.4;
the pH value of the ammonia absorption liquid before tempering is 4.5-5.6, and the pH value after tempering is 7.0-8.8;
the ratio of the process liquid to the ammonia absorption liquid for absorbing ammonia water is 1 (0.5-2.0).
7. The method for treating iron phosphate mother liquor and washing water according to claim 1,
in S130, the product fertilizer comprises ammonium sulfate and monoammonium phosphate; wherein, the monoammonium phosphate is obtained by one or more operations of cooling crystallization, solid-liquid separation and drying of partial centrifugal mother liquor of the ammonium sulfate.
8. The method for treating iron phosphate mother liquor and washing water according to claim 7, wherein after S130, the method further comprises:
s140, dissolving the monoammonium phosphate in water, and further reacting the monoammonium phosphate with the ammonia water to obtain diammonium phosphate.
9. The method for treating the ferric phosphate mother liquor and the washing water is characterized by further comprising the following steps:
s210, absorbing gas ammonia by using mother liquor to be treated to obtain process liquor, absorbing gas ammonia by using washing water to be treated to obtain ammonia absorption liquor, and absorbing gas ammonia by using process water to obtain ammonia water;
wherein the gas ammonia is generated by gasifying liquid ammonia by the heat released by the mother liquor in the process of absorbing the gas ammonia;
s220, mixing the ammonia absorption liquid with the process liquid after evaporation concentration operation including but not limited to, so as to obtain a mixed liquid;
s230, tempering the mixed solution by using the ammonia water and the potassium dihydrogen phosphate;
s240, performing one or more operations of evaporation concentration and hot air drying on the tempered mixed solution to obtain the product compound fertilizer.
10. A treatment system for iron phosphate mother liquor and washing water, which is applied to the treatment method according to any one of claims 1 to 8, and is characterized by comprising:
the mother liquor ammonia absorption cooling equipment is used for preparing process liquid by absorbing gas ammonia with mother liquor and cooling the process liquid; and
the washing water ammonia absorption equipment is used for preparing ammonia absorption liquid by washing water absorption gas ammonia;
the ammonia water preparation equipment is used for preparing ammonia water by absorbing gas ammonia with process water;
the liquid ammonia gasification equipment is used for gasifying liquid ammonia by utilizing heat released by absorbing gas ammonia by the mother liquor, and respectively provides gas ammonia for the mother liquor ammonia absorption cooling equipment, the washing water ammonia absorption equipment and the ammonia water preparation equipment through gas ammonia pipelines;
the tempering equipment is respectively connected with the mother liquor ammonia absorption cooling equipment, the washing water ammonia absorption equipment and the ammonia water preparation and is used for tempering the process liquid and the ammonia absorption liquid by using the ammonia water; or the ammonia water conditioning system is respectively connected with the mother liquor ammonia absorption cooling equipment, the washing water ammonia absorption equipment and the ammonia water preparation and is used for conditioning the mixed solution of the process solution and the ammonia absorption solution by using the ammonia water and potassium dihydrogen phosphate;
and the fertilizer production equipment is connected with the conditioning equipment and is used for preparing a product fertilizer after one or more operations of filtering, evaporating and concentrating, centrifuging, separating solid from liquid, drying and cooling and crystallizing the conditioned process liquid and the conditioned ammonia absorption liquid.
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| CN114772835A (en) * | 2022-05-25 | 2022-07-22 | 雅安天蓝新材料科技有限公司 | Treatment process for wastewater from iron phosphate production |
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