CN112723404A - Method for separating calcium, magnesium and phosphorus in chemical beneficiation by-product - Google Patents
Method for separating calcium, magnesium and phosphorus in chemical beneficiation by-product Download PDFInfo
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- CN112723404A CN112723404A CN202110004418.XA CN202110004418A CN112723404A CN 112723404 A CN112723404 A CN 112723404A CN 202110004418 A CN202110004418 A CN 202110004418A CN 112723404 A CN112723404 A CN 112723404A
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- magnesium
- calcium
- potassium
- nitrate
- phosphorus
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- 239000011575 calcium Substances 0.000 title claims abstract description 55
- 229910052791 calcium Inorganic materials 0.000 title claims abstract description 55
- 239000011777 magnesium Substances 0.000 title claims abstract description 52
- 229910052749 magnesium Inorganic materials 0.000 title claims abstract description 52
- 238000000034 method Methods 0.000 title claims abstract description 52
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 title claims abstract description 49
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 title claims abstract description 46
- 239000000126 substance Substances 0.000 title claims abstract description 39
- 239000006227 byproduct Substances 0.000 title claims abstract description 36
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 title claims abstract description 24
- 239000011574 phosphorus Substances 0.000 title claims abstract description 24
- 229910052698 phosphorus Inorganic materials 0.000 title claims abstract description 24
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 claims abstract description 97
- 238000005406 washing Methods 0.000 claims abstract description 63
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims abstract description 62
- 239000004323 potassium nitrate Substances 0.000 claims abstract description 50
- 235000010333 potassium nitrate Nutrition 0.000 claims abstract description 50
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 claims abstract description 38
- 229910052939 potassium sulfate Inorganic materials 0.000 claims abstract description 38
- 235000011151 potassium sulphates Nutrition 0.000 claims abstract description 38
- 238000002386 leaching Methods 0.000 claims abstract description 34
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 32
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims abstract description 32
- 239000010452 phosphate Substances 0.000 claims abstract description 32
- 238000000926 separation method Methods 0.000 claims abstract description 31
- SNNUUXJFRJODOJ-UHFFFAOYSA-N [Mg++].[K+].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O Chemical compound [Mg++].[K+].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O SNNUUXJFRJODOJ-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000012452 mother liquor Substances 0.000 claims abstract description 28
- RBIDTZUOKZFXOO-UHFFFAOYSA-O [N+](=O)([O-])[O-].[NH4+].[Mg].[Ca] Chemical compound [N+](=O)([O-])[O-].[NH4+].[Mg].[Ca] RBIDTZUOKZFXOO-UHFFFAOYSA-O 0.000 claims abstract description 26
- 239000002367 phosphate rock Substances 0.000 claims abstract description 25
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 claims abstract description 25
- 238000001914 filtration Methods 0.000 claims abstract description 24
- 238000001035 drying Methods 0.000 claims abstract description 20
- 238000003825 pressing Methods 0.000 claims abstract description 19
- 238000001354 calcination Methods 0.000 claims abstract description 17
- RPASNPADOARUAP-UHFFFAOYSA-N calcium magnesium tetranitrate Chemical compound [Mg++].[Ca++].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O RPASNPADOARUAP-UHFFFAOYSA-N 0.000 claims abstract description 17
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 12
- 239000011591 potassium Substances 0.000 claims abstract description 12
- 239000002994 raw material Substances 0.000 claims abstract description 12
- 238000005469 granulation Methods 0.000 claims abstract description 10
- 230000003179 granulation Effects 0.000 claims abstract description 10
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 9
- 239000011707 mineral Substances 0.000 claims abstract description 9
- ZFXVRMSLJDYJCH-UHFFFAOYSA-N calcium magnesium Chemical compound [Mg].[Ca] ZFXVRMSLJDYJCH-UHFFFAOYSA-N 0.000 claims abstract description 8
- 239000000706 filtrate Substances 0.000 claims abstract description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 45
- 238000002425 crystallisation Methods 0.000 claims description 40
- 230000008025 crystallization Effects 0.000 claims description 40
- 239000012065 filter cake Substances 0.000 claims description 34
- 239000007788 liquid Substances 0.000 claims description 33
- 238000006243 chemical reaction Methods 0.000 claims description 29
- 239000013078 crystal Substances 0.000 claims description 23
- 238000001704 evaporation Methods 0.000 claims description 19
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims description 16
- 239000012141 concentrate Substances 0.000 claims description 12
- 230000008020 evaporation Effects 0.000 claims description 12
- 230000035484 reaction time Effects 0.000 claims description 12
- 239000000395 magnesium oxide Substances 0.000 claims description 11
- 238000003756 stirring Methods 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- INIZPXBLAMXMBJ-UHFFFAOYSA-O azanium;magnesium;nitrate Chemical compound [NH4+].[Mg].[O-][N+]([O-])=O INIZPXBLAMXMBJ-UHFFFAOYSA-O 0.000 claims description 6
- 239000004137 magnesium phosphate Substances 0.000 claims description 6
- 229910000157 magnesium phosphate Inorganic materials 0.000 claims description 6
- 229960002261 magnesium phosphate Drugs 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 6
- 238000012545 processing Methods 0.000 claims description 5
- 239000002002 slurry Substances 0.000 claims description 5
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims description 4
- 239000000920 calcium hydroxide Substances 0.000 claims description 4
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 238000004140 cleaning Methods 0.000 claims description 3
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Inorganic materials [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 claims description 3
- 229910021529 ammonia Inorganic materials 0.000 claims description 2
- 230000000717 retained effect Effects 0.000 claims description 2
- 239000000047 product Substances 0.000 abstract description 27
- 238000003912 environmental pollution Methods 0.000 abstract description 5
- 230000029087 digestion Effects 0.000 abstract description 3
- NGLMYMJASOJOJY-UHFFFAOYSA-O azanium;calcium;nitrate Chemical compound [NH4+].[Ca].[O-][N+]([O-])=O NGLMYMJASOJOJY-UHFFFAOYSA-O 0.000 abstract 1
- 239000000843 powder Substances 0.000 abstract 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 15
- 239000003337 fertilizer Substances 0.000 description 14
- 238000010438 heat treatment Methods 0.000 description 9
- 238000001816 cooling Methods 0.000 description 8
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 description 7
- 238000011282 treatment Methods 0.000 description 7
- 230000005484 gravity Effects 0.000 description 6
- 238000003860 storage Methods 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000006386 neutralization reaction Methods 0.000 description 4
- DLYUQMMRRRQYAE-UHFFFAOYSA-N phosphorus pentoxide Inorganic materials O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 4
- 229910021532 Calcite Inorganic materials 0.000 description 3
- 229910000019 calcium carbonate Inorganic materials 0.000 description 3
- 238000004090 dissolution Methods 0.000 description 3
- 239000010459 dolomite Substances 0.000 description 3
- 229910000514 dolomite Inorganic materials 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 230000007613 environmental effect Effects 0.000 description 3
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 230000000996 additive effect Effects 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Inorganic materials [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 2
- SWHAQEYMVUEVNF-UHFFFAOYSA-N magnesium potassium Chemical compound [Mg].[K] SWHAQEYMVUEVNF-UHFFFAOYSA-N 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 1
- BHPQYMZQTOCNFJ-UHFFFAOYSA-N Calcium cation Chemical compound [Ca+2] BHPQYMZQTOCNFJ-UHFFFAOYSA-N 0.000 description 1
- JLVVSXFLKOJNIY-UHFFFAOYSA-N Magnesium ion Chemical compound [Mg+2] JLVVSXFLKOJNIY-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- YMKIRWHSXOBLCF-UHFFFAOYSA-N [Mg].[P].[Ca] Chemical compound [Mg].[P].[Ca] YMKIRWHSXOBLCF-UHFFFAOYSA-N 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- 229910001424 calcium ion Inorganic materials 0.000 description 1
- 239000001506 calcium phosphate Substances 0.000 description 1
- 229910000389 calcium phosphate Inorganic materials 0.000 description 1
- 235000011010 calcium phosphates Nutrition 0.000 description 1
- 229930002875 chlorophyll Natural products 0.000 description 1
- 235000019804 chlorophyll Nutrition 0.000 description 1
- ATNHDLDRLWWWCB-AENOIHSZSA-M chlorophyll a Chemical compound C1([C@@H](C(=O)OC)C(=O)C2=C3C)=C2N2C3=CC(C(CC)=C3C)=[N+]4C3=CC3=C(C=C)C(C)=C5N3[Mg-2]42[N+]2=C1[C@@H](CCC(=O)OC\C=C(/C)CCC[C@H](C)CCC[C@H](C)CCCC(C)C)[C@H](C)C2=C5 ATNHDLDRLWWWCB-AENOIHSZSA-M 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- YWEUIGNSBFLMFL-UHFFFAOYSA-N diphosphonate Chemical compound O=P(=O)OP(=O)=O YWEUIGNSBFLMFL-UHFFFAOYSA-N 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000011010 flushing procedure Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 238000003973 irrigation Methods 0.000 description 1
- 230000002262 irrigation Effects 0.000 description 1
- 239000001095 magnesium carbonate Substances 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 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
- 229910001425 magnesium ion Inorganic materials 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000007935 neutral effect Effects 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- QORWJWZARLRLPR-UHFFFAOYSA-H tricalcium bis(phosphate) Chemical compound [Ca+2].[Ca+2].[Ca+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O QORWJWZARLRLPR-UHFFFAOYSA-H 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/36—Nitrates
- C01F11/42—Double salts
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D9/00—Nitrates of sodium, potassium or alkali metals in general
- C01D9/08—Preparation by double decomposition
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F11/00—Compounds of calcium, strontium, or barium
- C01F11/46—Sulfates
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Inorganic Chemistry (AREA)
- Geology (AREA)
- Agronomy & Crop Science (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention relates to a method for separating calcium, magnesium and phosphorus from chemical beneficiation byproducts, which takes middle-low grade phosphorite as a raw material, and carries out crushing, calcining, digestion, leaching, filter pressing separation, and the calcium and magnesium containing leaching solution obtained after the filter pressing separation is concentrated to obtain ammonium nitrate calcium and magnesium concentrated solution with the mass concentration of more than 25%; preparing a potassium sulfate solution with the concentration of 20-50%; reacting the concentrated solution of calcium magnesium ammonium nitrate with a potassium sulfate solution for decalcification filtration, wherein the filtrate after decalcification filtration is subjected to centrifugal separation to obtain potassium nitrate, and the crystallized mother liquor after centrifugal separation is subjected to concentration granulation to obtain potassium magnesium nitrate/potassium calcium magnesium nitrate; washing and drying the decalcified and filtered filter residue to obtain a calcium sulfate powder product; the invention takes the concentrated solution of calcium magnesium ammonium nitrate in the by-products of mineral separation of medium and low grade phosphate ores as raw materials, and prepares calcium sulfate, potassium nitrate and magnesium potassium nitrate/calcium magnesium potassium nitrate simultaneously, thereby effectively solving the problems of comprehensive utilization of medium and low grade phosphate ores, environmental pollution caused by occupation of a large amount of land in phosphate tailings and the like.
Description
Technical Field
The invention relates to the technical field of chemical beneficiation by-product treatment, in particular to a method for separating calcium, magnesium and phosphorus in chemical beneficiation by-products.
Background
China's storage of phosphate ore is second in the world, but compared with the related aspects in the world, the storage of phosphate ore has larger difference in the aspects of ore quality, selectivity, phosphate ore mining and the like, the basic storage of the phosphate ore available for processing and utilization is relatively lower, only 40.54 hundred million tons, and a lot of low-grade ores exist, and P is P2O5The mass fraction of rich ore is more than 30 percent and is only 11.08 hundred million tons, and the Chinese phosphorite P2O5The average mass fraction is about 17 percent, most of phosphate ores can meet the production requirements of phosphoric acid and high-concentration phosphate fertilizers after being enriched, and according to the current speed of exploiting phosphate ores, if the rich ores with the mass fraction of 30 percent can be maintained for about 10 years, the economic reserves can be maintained for about 40 years, and the middle and low-grade phosphate ores with higher cost are forced to be exploited in the future.
Therefore, in the prior art, how to fully utilize the by-products generated in the chemical beneficiation process is researched; for example, in the prior art, a calcium magnesium nitrate liquid fertilizer can be prepared from chemical beneficiation byproducts, and the calcium magnesium nitrate fertilizer is an efficient medium-element water-soluble fertilizer, can adjust the pH value of soil, promotes the absorption of nitrogen, phosphorus and potassium in the soil by crops, increases the chlorophyll content, promotes the formation of sugar water compounds, enhances the resistance of the crops and the like. The calcium magnesium nitrate fertilizer is a neutral fertilizer, has the characteristics of quick fertilizer effect and good absorption, can be used as a base fertilizer and an additional fertilizer, is widely applied to greenhouses, greenhouses and large-area farmlands, and can promote the growth and development of roots, stems and leaves of plants. In addition, the application mode of the calcium nitrate magnesium liquid fertilizer is flexible, and the calcium nitrate magnesium liquid fertilizer can be applied in various modes such as flushing application, drip irrigation, foliage spraying and the like.
In the prior art, for example, the document with the application number of 201510889509.0 discloses a process for preparing phosphate concentrate and by-products of calcium carbonate and magnesium oxide from medium and low grade phosphate ore, which comprises the following steps: calcining the middle-low grade phosphorite or phosphate tailings at the temperature of 900 ℃ and 1100 ℃; then a series of treatments such as digestion, leaching and precipitation are carried out to obtain phosphate concentrate, calcium carbonate and magnesium oxide. The washing capacity requirement is large, the steps are complex, leaching needs to be carried out twice, two acid radicals of two leaching systems of ammonium nitrate and ammonium sulfate can influence each other, the leaching efficiency is reduced, and the purity of a final product can be influenced. Therefore, in the prior art, if calcium and magnesium separation is required, a mode of leaching twice is adopted and then synthesis is respectively carried out, calcium and magnesium products are obtained as a mixture and are obtained simultaneously, the washing amount in the whole process is large, and the operation is complex; meanwhile, the obtained calcium-magnesium product mixture has low utilization value and greatly limited application range.
Disclosure of Invention
Aiming at the existing technologies such as: in the prior art, when a calcium-magnesium-phosphorus product is extracted from a chemical beneficiation byproduct, no method is simple to operate, and calcium, magnesium and phosphorus resources are prepared and recovered simultaneously; the process for obtaining high-quality calcium and magnesium products.
In particular to a method for separating calcium, magnesium and phosphorus in a chemical beneficiation byproduct, which comprises the following steps:
taking middle-low grade phosphorite as a raw material, sequentially crushing, calcining, digesting, leaching, filter-pressing and separating, and concentrating a calcium and magnesium containing leaching solution obtained after filter-pressing and separating to obtain a calcium and magnesium ammonium nitrate concentrated solution with the mass concentration of more than 25%;
preparing a potassium sulfate solution with the concentration of 20-50%;
reacting the calcium magnesium ammonium nitrate concentrated solution with a potassium sulfate solution to carry out decalcification filtration, wherein the decalcification filtration filtrate is concentrated and crystallized to obtain potassium nitrate, and the concentrated and crystallized crystallization mother liquor is concentrated and granulated to obtain potassium magnesium nitrate/potassium calcium magnesium nitrate; and drying the decalcified and filtered filter residue to obtain calcium sulfate.
Preferably, the crushing comprises crushing the middle-low grade phosphorite to the particle size of less than or equal to 4.5mm, the calcining temperature is 900-2O5The low-magnesium phosphate concentrate contains not less than 34.5 percent of MgO and not more than 0.85 percent of MgO.
Preferably, the calcium and magnesium containing leaching solution discharged by filter pressing separation is concentrated, and a double-effect countercurrent evaporation device is adopted in a concentration system.
Preferably, the reaction temperature is 20-110 ℃ and the reaction time is 3-6h when the decalcification filtration is carried out; the alkaline substance is one of calcium hydroxide and ammonia.
Preferably, the decalcified slurry is filtered using one of a cake vacuum filter, a plate and frame filter, and a rotary disc filter, and the cake is washed with water to obtain a washing liquid for dissolving potassium sulfate.
Preferably, the filter cake is washed once with water again to obtain two wash solutions, which are retained as wash water for the first washing of the filter cake in the next manufacturing process cycle.
Preferably, the potassium sulfate liquid is prepared by heating to 40-70 ℃ with stirring.
Preferably, when the concentration and crystallization are carried out, the working temperature is 100-; and the condensed water produced in the concentration process is used for cleaning the filter cake.
Preferably, the potassium nitrate crystals obtained by the centrifugal separation after the concentration and crystallization are washed and dried to obtain potassium nitrate; concentrating and granulating the crystallization mother liquor after centrifugal separation.
Preferably, the crystallization mother liquor is sent to a preheater for preheating and then sent to a heat exchanger for heat exchange, the mother liquor is sent to a forced circulation type evaporator for evaporation after heat exchange through the heat exchanger, wherein the temperature of the evaporation feed liquor is 140-165 ℃, the evaporated material is separated by a high-efficiency flash separator and then is sent to a granulator for granulation, and the temperature is reduced to the optimum granulation temperature of 100-120 ℃ after heat exchange with the evaporation feed liquor through the heat exchanger, and the potassium magnesium nitrate/potassium calcium magnesium nitrate is obtained.
The invention has the beneficial effects that:
the invention provides a method for separating calcium, magnesium and phosphorus from chemical beneficiation byproducts, which comprises the following steps: taking middle-low grade phosphorite as a raw material, sequentially crushing, calcining, digesting, leaching, filter-pressing and separating, and concentrating a calcium and magnesium containing leaching solution obtained after filter-pressing and separating to obtain a calcium and magnesium ammonium nitrate concentrated solution with the mass concentration of more than 25%; preparing a potassium sulfate solution with the concentration of 20-50%; adding the calcium magnesium ammonium nitrate concentrated solution and the potassium sulfate solution into a decalcification reaction tank at the same time for decalcification reaction, adding an alkaline substance for neutralization, and then filtering, wherein the decalcification filtrate obtained by decalcification filtration is subjected to concentration crystallization and separation to obtain potassium nitrate, and the separated crystallization mother liquor is subjected to concentration granulation to obtain potassium magnesium nitrate/potassium calcium magnesium nitrate; drying the decalcified and filtered filter residue to obtain calcium sulfate; the invention takes the concentrated solution of calcium magnesium ammonium nitrate in the by-products of mineral separation of medium and low grade phosphate ores as raw materials, and prepares calcium sulfate, potassium nitrate and magnesium potassium nitrate/calcium magnesium potassium nitrate simultaneously, thereby effectively solving the problems of comprehensive utilization of medium and low grade phosphate ores, environmental pollution caused by occupation of a large amount of land in phosphate tailings and the like.
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 is a flow chart of the method of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are conventionally placed in use, and are only used for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.
Furthermore, the terms "horizontal", "vertical", "suspended", and the like do not imply that the components are required to be absolutely horizontal or suspended, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.
In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Some embodiments of the invention are described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.
In order to more clearly express the present invention, the present invention will be further described below with reference to examples.
The storage capacity of phosphorite in China is the second place in the world, but about 80% of the storage capacity is middle-low grade phosphorite, most of which is refractory middle-low grade collophanite, the mineral particles are fine and closely embedded, and associated magnesium and other impurities are higher, so that the grade of the phosphorite can be reduced, the sulfuric acid consumption during wet treatment of the phosphorite is increased, and the deep processing process of phosphoric acid and phosphate and the quality of products are influenced. Mineral processing is carried out to low-grade phosphorite in the tradition to this reduces the content of impurity such as magnesium in the phosphorite, then carries out deep-processing next step, with the degree of difficulty that reduces follow-up phosphorite and utilize. However, after beneficiation, phosphate tailings which are difficult to treat are generated, and the loss rate of phosphorus is large. The types of the by-product calcium-magnesium mixtures generated after chemical beneficiation are disordered, and the reuse degree of the tailings in the prior art is not high, so that a method for recycling and extracting calcium, magnesium and phosphorus resources aiming at the by-products of chemical beneficiation is needed, the operation procedures are few, and high-quality calcium and magnesium products are obtained; the discharge of three wastes is reduced, and the pollution to the environment is reduced; it should be noted that the medium-low grade phosphorus ore refers to phosphorus ore with a mass content of phosphorus pentoxide less than 30%, and mainly contains calcium phosphate, calcium fluoride, dolomite and calcite, and in some specific embodiments of the present invention, the medium-low grade phosphorus ore includes the following components by mass: p2O5-24.34％、CaO-41.03％、MgO-4.79％、Fe2O3-0.34％、Al2O3-0.41％、F-3.16％、SiO2-3.38%, acid insoluble 4.50%, organic matter 0.46%.
In particular to a method for separating calcium, magnesium and phosphorus in a by-product of chemical beneficiation, please refer to fig. 1, which comprises the following steps:
taking middle-low grade phosphorite as a raw material, sequentially crushing, calcining, digesting, leaching, filter-pressing and separating, and concentrating a calcium and magnesium containing leaching solution obtained after filter-pressing and separating to obtain a calcium and magnesium ammonium nitrate concentrated solution with the mass concentration of more than 25%;
firstly, crushing the mixture until the particle size is less than or equal to 4.5 mm. WhileThe temperature of the raw ore for calcination treatment has a great influence on the decomposition degree of dolomite, calcite and organic matters in the phosphorite raw ore. In view of the above, in a preferred embodiment, the raw phosphorite is calcined at the temperature of 900-1100 ℃, so as to ensure that the decomposition of calcium carbonate and magnesium carbonate (including calcite and dolomite) in the raw phosphorite is controlled within a reasonable range, so that the calcium and magnesium contents in the finally obtained phosphate concentrate and calcium magnesium nitrate liquid fertilizer are both within a reasonable range, wherein the mass percentage of magnesium oxide in the phosphate concentrate is below 0.85%; if the calcining temperature is too low, the decomposition rate of calcium carbonate salt and magnesium carbonate salt in the raw phosphorite ore is low, even decomposition reaction can not occur, so that the calcium content and the magnesium content in the phosphate concentrate, particularly the magnesium content, exceed the standard, and therefore, for the subsequent preparation of low-magnesium phosphate concentrate, the calcining temperature is controlled at 900-1100 ℃ for 1.5-4 h; leaching reaction temperature is 75-90 ℃, reaction time is 2-5h, and reaction pH is 4.0-6.5; if the calcining temperature is too high, the raw phosphorite ore is too little at the too high calcining temperature, and the preparation of the low-magnesium phosphate concentrate can not be met; the subsequent leaching and filter pressing separation are not facilitated; leaching and demagging and leaching and decalcification are needed after calcination, and certainly, in order to better perform leaching and demagging, grinding can be performed in a water environment after calcination, and then leaching is performed, wherein reactions in the leaching and demagging processes mainly include that calcium and magnesium in calcium hydroxide and magnesium hydroxide are leached into calcium ions and magnesium ions which enter leaching solution, the reaction temperature during leaching is 75-90 ℃, and the reaction time is 120-300 min; thereby removing calcium and magnesium; and carrying out filter-pressing separation treatment after leaching decalcification and leaching demagging, and concentrating the filtrate discharged from the filter press. After filter pressing separation, concentrating the slurry to obtain concentrated solution of ammonium nitrate calcium magnesium with mass concentration of more than 25% and P2O5The low-magnesium phosphate concentrate contains not less than 34.5 percent of MgO and not more than 0.85 percent of MgO.
Preparing a potassium sulfate solution with the concentration of 20-50% after preparing a calcium magnesium ammonium nitrate concentrated solution in advance; simultaneously adding the concentrated solution of calcium magnesium ammonium nitrate and the potassium sulfate solution into a decalcification reaction tank for decalcification reaction, and then adding an alkaline substance for neutralization reaction;
filtering the slurry after reaction, wherein the filtrate after decalcification and filtration is concentrated and crystallized to obtain potassium nitrate, and the crystallized mother liquor after concentration and crystallization is concentrated and granulated to obtain potassium magnesium nitrate/potassium calcium magnesium nitrate; and drying the decalcified and filtered filter residue to obtain calcium sulfate. Therefore, the mineral separation by-products can be utilized to simultaneously prepare calcium sulfate, potassium nitrate and magnesium potassium nitrate/magnesium potassium calcium nitrate, no tailings are generated, and the filtrate generated in the process period can be reserved in the preparation of potassium sulfate solution in the next process cycle, so that resources are fully utilized. The obtained calcium sulfate, potassium nitrate, potassium magnesium nitrate/potassium calcium magnesium nitrate can be directly sold, can also be used as a raw material of a fertilizer product, an additive of the fertilizer product and an additive of a chemical product, and has wide application.
In some embodiments of the invention, the calcium and magnesium containing leachate discharged from the filter press is pumped to a two-effect counter-current evaporation device for concentration to obtain a calcium and magnesium ammonium nitrate concentrated solution with a concentration of more than 25%; can be concentrated efficiently and rapidly. The concentration of the solution is increased in each effect in turn, and simultaneously the temperature is increased, so that the viscosity of the solution in each effect is not changed greatly, and the process is suitable for evaporating the solution with the viscosity greatly changing along with the concentration and the temperature.
In some embodiments of the invention, the reaction temperature is 20-110 ℃ and the reaction time is 3-6h when decalcification filtration is carried out; adding alkaline substance calcium hydroxide for neutralization reaction after decalcification. This is advantageous in precipitating calcium and promoting the separation of calcium and magnesium, and in contrast to the above-described operation, the filtration is generally performed by one of a vacuum filter, a plate and frame filter, and a rotary disc filter.
In some embodiments of the invention, the decalcifying filtration is performed using one of a vacuum filter, a plate and frame filter, and a rotary disc filter, and the filter cake is washed with water to obtain a washing solution, which is used to dissolve the potassium sulfate. Therefore, the water resource can be repeatedly utilized, and the nitrate and the removed substances can be fully utilized.
In some embodiments of the invention, the filter cake is washed again with water after a first wash to provide a second wash, which is the liquid that is left to wash the filter cake for the first time in the process cycle for the next preparation.
In some embodiments of the invention, the potassium sulfate liquid is heated to 40-70 ℃ under stirring; at this time, the dissolution is rapid and the reaction is fast.
In some embodiments of the invention, during the concentration and crystallization, the working temperature during the concentration is 100-; and the condensed water generated in the cooling crystallization process is used for cleaning the filter cake. In this case, potassium nitrate crystals can be rapidly precipitated by the concentrated crystals, and potassium nitrate can be obtained after drying.
In some embodiments of the invention, centrifugal separation is performed after the concentration and crystallization, and the separated potassium nitrate crystals are washed and dried to obtain potassium nitrate; concentrating and granulating the crystallization mother liquor after centrifugal separation.
In some embodiments of the invention, the crystallization mother liquor is preheated and then added into a heat exchanger, and enters a forced circulation type evaporator, wherein the temperature of the evaporation feed liquor is 120-145 ℃, and the material after evaporation is sent to a granulator for granulation when the temperature of the material is reduced to 100-120 ℃ by a flash separator; obtaining the potassium magnesium nitrate/potassium calcium magnesium nitrate. Thereby simultaneously obtaining calcium sulfate, potassium nitrate and magnesium potassium nitrate/magnesium potassium calcium nitrate from a complete process; and in the water resources used in the first washing and the second washing, the first washing liquid can be continuously put into the dissolution of the potassium sulfate, so that the potassium sulfate trapped in the filter cake and part of unreacted calcium magnesium ammonium nitrate slurry are fully utilized for decalcification.
Flow of implementation
Taking middle-low grade phosphorite as raw material, preparing P by the working procedures of crushing, calcining, digesting, leaching, filter pressing separation and the like2O5The low-magnesium phosphate concentrate with the MgO content of more than or equal to 34.5 percent and the MgO content of less than or equal to 0.85 percent, or the by-product after the phosphorite ore dressing can be directly subjected to the subsequent treatment; pumping the calcium and magnesium containing leaching solution discharged from the filter press to a concentration system (a two-effect countercurrent evaporation device) to obtain a calcium and magnesium ammonium nitrate concentrated solution with the concentration of more than 25 percent; preparing potassium sulfate solution with concentration of 20-50%, mixing the concentrated solution of ammonium calcium magnesium nitrate and the potassium sulfate solutionAdding into a decalcification reaction tank for decalcification reaction, adding alkaline substance for neutralization, filtering with one of vacuum filter, plate-and-frame filter press and rotary disc filter, and concentrating the decalcification solution; at the same time, the filter cake is washed by adding water for the first time, the obtained first washing water is used for dissolving potassium sulfate, and the second washing water of the second washing is used for the first washing procedure of the filter cake of the next process cycle; the decalcified liquid sent to the concentration process is concentrated to the temperature of 100-. Pumping the crystallization mother liquor from the centrifugal separation process to a preheater, taking condensate generated by medium-pressure steam as a heating medium, feeding the preheated material into a heat exchanger, taking the evaporated crystallization mother liquor as the heating medium, feeding the heated crystallization mother liquor into a forced circulation type evaporator to ensure that the temperature of the evaporation feed liquid is 1240 and 165 ℃, separating the evaporated material through a flash separator, feeding the separated material into a granulation feeding tank, reducing the heat exchange of the concentrated solution and the feed liquid to be evaporated to the optimal granulation temperature of 100 and 120 ℃ through the heat exchanger, then feeding the concentrated solution into a granulator for granulation, cooling and screening, and wrapping to obtain a potassium magnesium nitrate/calcium magnesium nitrate product, wherein calcium sulfate, potassium nitrate, potassium magnesium nitrate/calcium magnesium nitrate can be obtained simultaneously in the whole process; the problems of comprehensive utilization of middle-low grade phosphate ore, environmental pollution caused by occupation of a large amount of land of phosphate tailings and the like are effectively solved; and materials in all links are recycled, so that the washing water amount is greatly reduced, the water consumption is reduced, and the washing water is completely recycled, so that the method has obvious environmental protection significance. The content of the calcium sulfate obtained by the process is more than 98 percent, and the whiteness is more than 95 percent; the potassium nitrate meets the agricultural grade potassium nitrate standard; the potassium magnesium nitrate contains more than 25% of N, K2More than O14 percent and more than Mg5 percent.
Example 1
The method comprises the following steps: metering 160kg of potassium sulfate on green, adding 408kg of the first batch of washing liquor, and heating to 40 ℃ under the condition of stirring for later use;
step two: 600kg of by-product calcium magnesium ammonium nitrate concentrated solution (N) from chemical ore dressing is measuredGeneral assembly12.95％、NAmmonium salt3.45%, CaO7.27%, MgO3.98%, specific gravity 1.406, pH 6.78) for use;
step three: adding a small amount of seed crystals into the first step, slowly adding the calcium magnesium ammonium nitrate concentrated solution obtained in the second step into the first step for decalcification reaction, controlling the reaction temperature at 40 ℃ and the reaction time for 3 hours, filtering to obtain 916kg of decalcification solution, adding 400kg of water into a filter cake for first washing to obtain 439kg of first washing solution, using the first washing solution as a potassium sulfate solution prepared in the next batch, adding 400kg of water into the filter cake for second washing to obtain 401kg of second washing solution, and drying the filter cake to obtain 105kg of calcium sulfate, wherein the content of the calcium sulfate product is 98.35% and the whiteness is 95.48%.
Step four: concentrating the decalcified solution obtained in step three to 100 deg.C, evaporating to remove water 266kg, cooling to room temperature, controlling crystallization time to about 4 hr, centrifuging to obtain 500kg of crystallization mother liquor and 115kg of potassium nitrate crystal (wet), drying potassium nitrate crystal to obtain 108K potassium nitrate product containing 13.65% of N and 13.65% of K2O45.06％。
Step five: directly concentrating the crystallization mother liquor obtained in the step four to 145 ℃, and granulating to obtain potassium magnesium nitrate, wherein the product contains NGeneral assembly26.17％、NAmmonium salt8.61％、K2O 14.35％、Ca 0.59％、Mg 5.97％。
Example 2
The method comprises the following steps: metering 160kg of potassium sulfate on green, adding 408kg of the first batch of washing liquid, and heating to 45 ℃ under the stirring condition for later use;
step two: 600kg of by-product calcium magnesium ammonium nitrate concentrated solution (N) from chemical ore dressing is measuredGeneral assembly12.95％、NAmmonium salt3.45%, CaO7.27%, MgO3.98%, specific gravity 1.406, pH 6.78) for use;
step three: adding a small amount of seed crystals into the first step, slowly adding the calcium magnesium ammonium nitrate concentrated solution obtained in the second step into the first step for decalcification reaction, controlling the reaction temperature at 45 ℃ and the reaction time for 6 hours, filtering to obtain 916kg of decalcification solution, adding 500kg of water into a filter cake for first washing to obtain 499kg of first washing liquid, using the first washing liquid as a potassium sulfate solution prepared in the next batch, adding 500kg of water into the filter cake for second washing to obtain 411kg of second washing liquid, and drying the filter cake to obtain 100kg of calcium sulfate, wherein the content of the calcium sulfate product is 97.11% and the whiteness is 94.89%.
Step four: concentrating the decalcified solution obtained in step three to 135 deg.C, evaporating water 281kg, cooling to room temperature, controlling crystallization time to about 5 hr, centrifuging to obtain 520kg of crystallization mother liquor and 135kg of potassium nitrate crystal (wet), drying potassium nitrate crystal to obtain 112K potassium nitrate product containing N14.65% and K2O46.06％。
Step five: directly concentrating the crystallization mother liquor obtained in the step four to 165 ℃, and granulating to obtain potassium magnesium nitrate, wherein the product contains NGeneral assembly26.01％、NAmmonium salt8.21％、K2O 15.35％、Ca 0.51％、Mg 5.27％。
Example 3
The method comprises the following steps: metering 200kg of potassium sulfate on green, adding 470kg of the first batch of washing liquid, and heating to 43 ℃ under the stirring condition for later use;
step two: 600kg of by-product calcium magnesium ammonium nitrate concentrated solution (N) from chemical ore dressing is measuredGeneral assembly13.15％、NAmmonium salt3.45%, CaO7.27%, MgO3.98%, specific gravity 1.486, pH 6.58) for use;
step three: adding a small amount of seed crystals into the first step, slowly adding the calcium magnesium ammonium nitrate concentrated solution obtained in the second step into the first step for decalcification reaction, controlling the reaction temperature at 45 ℃ and the reaction time for 5.5 hours, filtering to obtain 960kg of decalcification solution, adding 400kg of water into a filter cake for first washing to obtain 521kg of first washing solution, taking the first washing solution as a potassium sulfate solution prepared in the next batch, adding 500kg of water into the filter cake for second washing to obtain 431kg of second washing solution, and drying the filter cake to obtain 120kg of calcium sulfate, wherein the content of the calcium sulfate is 96.91% and the whiteness is 95.16%.
Step four: concentrating the decalcified solution obtained in the third step to 133 ℃, namely evaporating 301kg of water, cooling to room temperature, controlling the crystallization time to be about 4.5h, performing centrifugal separation to obtain 542kg of crystallization mother liquor and 155kg of potassium nitrate crystals (wet), and drying the potassium nitrate crystals to obtain 132K potassium nitrate product containing 16.65 percent of N and 16.65 percent of K2O48.06％。
Step five: will be described in detailDirectly concentrating the crystallization mother liquor to 160 ℃, and granulating to obtain the magnesium potassium nitrate, wherein the product contains NGeneral assembly26.81％、NAmmonium salt7.91％、K2O 16.32％、Ca 0.62％、Mg 5.17％。
Example 4
The method comprises the following steps: metering 170kg of potassium sulfate on green, adding 418kg of the first batch of washing liquid, and heating to 45 ℃ under the stirring condition for later use;
step two: 600kg of by-product calcium magnesium ammonium nitrate concentrated solution (N) from chemical ore dressing is measuredGeneral assembly12.88％、NAmmonium salt3.45%, CaO6.97%, MgO4.18%, specific gravity 1.406, pH 6.78) for use;
step three: adding a small amount of seed crystals into the first step, slowly adding the concentrated solution of calcium magnesium ammonium nitrate in the second step into the first step for decalcification reaction, controlling the reaction temperature at 43 ℃ and the reaction time for 5 hours, filtering to obtain 876kg of decalcification solution, adding 480kg of water into a filter cake for first washing to obtain 461kg of first washing liquid, taking the first washing liquid as a potassium sulfate solution prepared in the next batch, adding 480kg of water into the filter cake for second washing to obtain 400kg of second washing liquid, and drying the filter cake to obtain 90kg of calcium sulfate, wherein the content of the calcium sulfate is 97.62% and the whiteness is 95.13%.
Step four: concentrating the decalcified liquid obtained in the third step to 137 ℃, namely evaporating 260kg of water, cooling to room temperature, controlling the crystallization time to be about 4.3h, centrifugally separating to obtain 502kg of crystallization mother liquid and 135kg of potassium nitrate crystals (wet), drying the potassium nitrate crystals to obtain 112K potassium nitrate products containing 15.65 percent of N and 15.65 percent of K2O47.12％。
Step five: directly concentrating the crystallization mother liquor obtained in the fourth step to 155 ℃, and granulating to obtain potassium magnesium nitrate, wherein the product contains NGeneral assembly27.91％、NAmmonium salt7.68％、K2O 16.35％、Ca 0.51％、Mg 5.01％。
Example 5
The method comprises the following steps: metering 120kg of potassium sulfate on green, adding 318kg of the first batch of washing liquid, and heating to 45 ℃ under the stirring condition for later use;
step two: 500kg of by-product calcium magnesium ammonium nitrate concentrated solution (N) from chemical ore dressing is measuredGeneral assembly12.95％、NAmmonium salt3.45％、CaO727%, mgo3.98%, specific gravity 1.406, pH 6.78) for use;
step three: adding a small amount of seed crystals into the first step, slowly adding the concentrated solution of calcium magnesium ammonium nitrate in the second step into the first step for decalcification reaction, controlling the reaction temperature at 45 ℃ and the reaction time for 6 hours, filtering to obtain 836kg of decalcification solution, adding 500kg of water into filter cakes for first washing to obtain 412kg of first washing liquid, taking the first washing liquid as a potassium sulfate solution prepared in the next batch, adding 500kg of water into the filter cakes for second washing to obtain 401kg of second washing liquid, and drying the filter cakes to obtain 88kg of calcium sulfate, wherein the content of the calcium sulfate is 94.11% and the whiteness is 95.19%.
Step four: concentrating the decalcified solution obtained in step three to 135 deg.C, evaporating water to 233kg, cooling to room temperature, controlling crystallization time to about 5 hr, centrifuging to obtain 480kg of crystallization mother liquor and 105kg of potassium nitrate crystal (wet), drying potassium nitrate crystal to obtain 98K potassium nitrate product containing N15.15% and K15%2O46.76％。
Step five: directly concentrating the crystallization mother liquor obtained in the step four to 160 ℃, and granulating to obtain potassium magnesium nitrate, wherein the product contains NGeneral assembly25.91％、NAmmonium salt8.21％、K2O 14.15％、Ca 0.51％、Mg 5.17％。
Example 6
The method comprises the following steps: weighing 80kg of potassium sulfate on green, adding 202kg of the first batch of washing liquor, and heating to 45 ℃ under the stirring condition for later use;
step two: metering 300kg of by-product calcium magnesium ammonium nitrate concentrated solution (N) from chemical ore dressingGeneral assembly12.95％、NAmmonium salt3.45%, CaO7.27%, MgO3.98%, specific gravity 1.406, pH 6.78) for use;
step three: adding a small amount of seed crystals into the first step, slowly adding the calcium magnesium ammonium nitrate concentrated solution obtained in the second step into the first step for decalcification reaction, controlling the reaction temperature at 45 ℃ and the reaction time for 6 hours, filtering to obtain 416kg of decalcification solution, adding 250kg of water into a filter cake for first washing to obtain 255kg of first washing solution, taking the first washing solution as a potassium sulfate solution prepared in the next batch, adding 250kg of water into the filter cake for second washing to obtain 211kg of second washing solution, and drying the filter cake to obtain 50kg of calcium sulfate, wherein the content of the calcium sulfate product is 98.11% and the whiteness is 95.89%.
Step four: concentrating the decalcified solution obtained in step three to 135 deg.C, evaporating to remove water 141kg, cooling to room temperature, controlling crystallization time to about 5 hr, centrifuging to obtain 260kg of crystallization mother liquor and 75kg of potassium nitrate crystal (wet), drying potassium nitrate crystal to obtain 62K potassium nitrate product containing N16.65% and K162O47.06％。
Step five: directly concentrating the crystallization mother liquor obtained in the fourth step to 150 ℃, and granulating to obtain potassium magnesium nitrate, wherein the product contains NGeneral assembly27.01％、NAmmonium salt7.91％、K2O 16.35％、Ca 0.51％、Mg 6.17％。
According to the embodiment, calcium sulfate, potassium nitrate and potassium magnesium nitrate/potassium calcium magnesium nitrate are obtained by taking the calcium and magnesium-containing leaching solution and potassium sulfate which are byproducts of chemical ore dressing as main raw materials, so that the problems of comprehensive utilization of medium and low grade phosphorite, environmental pollution caused by occupation of a large amount of land of phosphate tailings and the like are effectively solved; meanwhile, calcium and magnesium contained in calcium and magnesium leaching solution in chemical ore dressing are respectively extracted, so that the problems that calcium and magnesium are generally leached twice and are respectively synthesized and separated in the conventional phosphorite treatment, the required washing amount is large, and the operation is complicated are solved; the high-quality calcium sulfate, potassium nitrate, potassium magnesium nitrate/potassium calcium magnesium nitrate are obtained after sequential separation, so that the problem that high-quality phosphate concentrate is obtained by concentrating phosphate ores at present is solved, primary washing water and secondary washing water in the separation process and water required for dissolution can be recycled, and the method has economic value and environmental protection significance for the mineral industry, and because the calcium sulfate is obtained from filter cakes washed for multiple times, the process has no resource waste, and the fluidity is high, the whiteness quality is good, the content of the calcium sulfate is more than 98%, and the whiteness is more than 95%; the potassium nitrate meets the agricultural grade potassium nitrate standard; the potassium magnesium nitrate contains more than 25% of N, K2More than O14 percent and more than Mg5 percent.
The invention has the advantages that:
the invention takes middle-low grade phosphorite as raw material, sequentially carries out crushing, calcining, digestion, leaching, filter-pressing separation, and the leaching solution containing calcium and magnesium obtained after the filter-pressing separation is concentrated to obtainObtaining a calcium magnesium ammonium nitrate concentrated solution with the mass concentration of more than 25 percent; preparing a potassium sulfate solution with the concentration of 20-50%; reacting the calcium magnesium ammonium nitrate concentrated solution with a potassium sulfate solution to carry out decalcification filtration, wherein the decalcification filtration filtrate is concentrated and crystallized to obtain potassium nitrate, and the concentrated and crystallized crystallization mother liquor is concentrated and granulated to obtain potassium magnesium nitrate/potassium calcium magnesium nitrate; drying the decalcified and filtered filter residue to obtain calcium sulfate; the method takes the concentrated solution of calcium magnesium ammonium nitrate in the by-products of mineral separation of medium and low grade phosphate ores as the raw material, and prepares calcium sulfate, potassium nitrate and magnesium potassium nitrate/calcium magnesium potassium nitrate simultaneously, thereby effectively solving the problems of comprehensive utilization of medium and low grade phosphate ores and environmental pollution caused by occupation of a large amount of land in phosphate tailings; the amount of washing water is greatly reduced, the consumption of water is reduced, and the washing water is completely recycled, so that the method has obvious environmental protection significance; the content of the obtained calcium sulfate is more than 98 percent, and the whiteness is more than 95 percent; the potassium nitrate meets the agricultural grade potassium nitrate standard; the potassium magnesium nitrate contains more than 25% of N, K2More than O14 percent and more than Mg5 percent.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit 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.
The above disclosure is only for a few specific embodiments of the present invention, but the present invention is not limited thereto, and any variations that can be made by those skilled in the art are intended to fall within the scope of the present invention.
Claims (10)
1. A method for separating calcium, magnesium and phosphorus from chemical beneficiation byproducts is characterized by comprising the following steps:
taking middle-low grade phosphorite as a raw material, sequentially crushing, calcining, digesting, leaching, filter-pressing and separating, and concentrating a calcium and magnesium containing leaching solution obtained after filter-pressing and separating to obtain a calcium and magnesium ammonium nitrate concentrated solution with the mass concentration of more than 25%;
preparing a potassium sulfate solution with the concentration of 20-50%;
reacting the calcium magnesium ammonium nitrate concentrated solution with a potassium sulfate solution to carry out decalcification filtration, wherein the decalcification filtration filtrate is concentrated and crystallized to obtain potassium nitrate, and the concentrated and crystallized crystallization mother liquor is concentrated and granulated to obtain potassium magnesium nitrate/potassium calcium magnesium nitrate; and drying the decalcified and filtered filter residue to obtain calcium sulfate.
2. The method for separating calcium, magnesium and phosphorus from byproducts of chemical mineral separation according to claim 1, wherein the crushing comprises crushing middle and low grade phosphate ore to particle size of 4.5mm or less, the calcination temperature is 900-1100 ℃, the time is 1.5-4h, the leaching reaction temperature is 75-90 ℃, the reaction time is 2-5h, the reaction pH is 4.0-6.5, and P is obtained after filter pressing separation2O5The low-magnesium phosphate concentrate contains not less than 34.5 percent of MgO and not more than 0.85 percent of MgO.
3. The method for separating calcium, magnesium and phosphorus from chemical beneficiation by-products according to claim 1, wherein the calcium and magnesium containing leachate discharged by the filter-pressing separation is concentrated, and a double-effect counter-current evaporation device is adopted in a concentration system.
4. The method for separating calcium, magnesium and phosphorus from chemical beneficiation by-products according to claim 1, wherein the reaction temperature is 20-110 ℃ and the reaction time is 3-6h when decalcification filtration is carried out; the alkaline substance is one of calcium hydroxide and ammonia.
5. The method for separating calcium, magnesium and phosphorus from chemical beneficiation by-products according to claim 4, wherein the decalcified slurry is filtered by one of a filter cake vacuum filter, a plate and frame filter press and a rotary disc filter, and the filter cake is washed with water to obtain a washing liquid, and the washing liquid is used for dissolving potassium sulfate.
6. The method for separating calcium, magnesium and phosphorus from chemical beneficiation by-products according to claim 5, wherein the filter cake is washed once and then is washed again with water to obtain two washing liquids, and the two washing liquids are retained as washing water for washing the filter cake for the first time in a process cycle for the next preparation.
7. The method for separating calcium, magnesium and phosphorus from chemical beneficiation by-products according to claim 1, wherein in the preparation of the potassium sulfate liquid, the potassium sulfate liquid is heated to 40-70 ℃ under stirring.
8. The method for separating calcium, magnesium and phosphorus from the by-product of chemical beneficiation according to claim 1, wherein during concentration and crystallization, the working temperature during concentration is 100-; and the condensed water produced in the concentration process is used for cleaning the filter cake.
9. The method for separating calcium, magnesium and phosphorus from the chemical beneficiation by-product according to claim 8, wherein the potassium nitrate is obtained by washing and drying potassium nitrate crystals obtained by centrifugal separation after concentration and crystallization; concentrating and granulating the crystallization mother liquor after centrifugal separation.
10. The method for separating calcium, magnesium and phosphorus from byproducts of chemical mineral processing according to claim 9, wherein the crystallization mother liquor is preheated in a preheater and then sent to a heat exchanger for heat exchange, the mother liquor is subjected to heat exchange in the heat exchanger and then sent to a forced circulation type evaporator for evaporation, wherein the temperature of the evaporation feed liquor is 140-165 ℃, the evaporated material is separated by a high-efficiency flash separator, then subjected to heat exchange with the feed liquor to be evaporated through the heat exchanger, then cooled to the optimum granulation temperature of 100-120 ℃, and sent to a granulator for granulation, so as to obtain the magnesium potassium nitrate/calcium magnesium nitrate.
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