CN112723396A - Method for preparing magnesium oxide and calcium ammonium nitrate from chemical beneficiation by-product - Google Patents
Method for preparing magnesium oxide and calcium ammonium nitrate from chemical beneficiation by-product Download PDFInfo
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- CN112723396A CN112723396A CN202110004414.1A CN202110004414A CN112723396A CN 112723396 A CN112723396 A CN 112723396A CN 202110004414 A CN202110004414 A CN 202110004414A CN 112723396 A CN112723396 A CN 112723396A
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- magnesium
- calcium
- ammonium nitrate
- magnesium oxide
- filtrate
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- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 title claims abstract description 78
- 239000000395 magnesium oxide Substances 0.000 title claims abstract description 60
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 41
- NGLMYMJASOJOJY-UHFFFAOYSA-O azanium;calcium;nitrate Chemical compound [NH4+].[Ca].[O-][N+]([O-])=O NGLMYMJASOJOJY-UHFFFAOYSA-O 0.000 title claims abstract description 34
- 239000006227 byproduct Substances 0.000 title claims abstract description 26
- 239000000126 substance Substances 0.000 title claims abstract description 25
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 69
- 239000011777 magnesium Substances 0.000 claims abstract description 69
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 69
- 239000000706 filtrate Substances 0.000 claims abstract description 49
- 239000011575 calcium Substances 0.000 claims abstract description 39
- 238000005406 washing Methods 0.000 claims abstract description 38
- 238000002386 leaching Methods 0.000 claims abstract description 35
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 claims abstract description 33
- 229910052791 calcium Inorganic materials 0.000 claims abstract description 33
- 239000000047 product Substances 0.000 claims abstract description 29
- 238000006243 chemical reaction Methods 0.000 claims abstract description 28
- 238000000926 separation method Methods 0.000 claims abstract description 26
- 239000002002 slurry Substances 0.000 claims abstract description 26
- 239000012065 filter cake Substances 0.000 claims abstract description 25
- 239000002367 phosphate rock Substances 0.000 claims abstract description 23
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 claims abstract description 23
- 238000001354 calcination Methods 0.000 claims abstract description 20
- 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 15
- 238000001914 filtration Methods 0.000 claims abstract description 15
- 238000003825 pressing Methods 0.000 claims abstract description 13
- 239000012141 concentrate Substances 0.000 claims abstract description 12
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 10
- 239000002994 raw material Substances 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
- 239000004137 magnesium phosphate Substances 0.000 claims abstract description 8
- 229910000157 magnesium phosphate Inorganic materials 0.000 claims abstract description 8
- 229960002261 magnesium phosphate Drugs 0.000 claims abstract description 8
- ZFXVRMSLJDYJCH-UHFFFAOYSA-N calcium magnesium Chemical compound [Mg].[Ca] ZFXVRMSLJDYJCH-UHFFFAOYSA-N 0.000 claims abstract description 7
- 229910019142 PO4 Inorganic materials 0.000 claims description 23
- 239000000347 magnesium hydroxide Substances 0.000 claims description 22
- 229910001862 magnesium hydroxide Inorganic materials 0.000 claims description 22
- 239000010452 phosphate Substances 0.000 claims description 22
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 claims description 21
- 238000001704 evaporation Methods 0.000 claims description 20
- 230000008020 evaporation Effects 0.000 claims description 20
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 claims description 20
- 239000007788 liquid Substances 0.000 claims description 17
- 238000005469 granulation Methods 0.000 claims description 14
- 230000003179 granulation Effects 0.000 claims description 14
- 238000001035 drying Methods 0.000 claims description 12
- 238000010438 heat treatment Methods 0.000 claims description 10
- 235000010755 mineral Nutrition 0.000 claims description 8
- 230000035484 reaction time Effects 0.000 claims description 6
- 238000005507 spraying Methods 0.000 claims description 5
- 238000001816 cooling Methods 0.000 claims description 4
- 239000002245 particle Substances 0.000 claims description 4
- 238000012216 screening Methods 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 3
- 238000004537 pulping Methods 0.000 claims description 3
- 239000010959 steel Substances 0.000 claims description 3
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 abstract description 18
- 229910000019 calcium carbonate Inorganic materials 0.000 abstract description 9
- 239000000203 mixture Substances 0.000 abstract description 9
- 239000002699 waste material Substances 0.000 abstract description 7
- 238000004519 manufacturing process Methods 0.000 abstract description 4
- 239000000243 solution Substances 0.000 description 63
- 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 description 13
- 239000003337 fertilizer Substances 0.000 description 13
- 238000006386 neutralization reaction Methods 0.000 description 11
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 10
- 229910002651 NO3 Inorganic materials 0.000 description 10
- 235000011114 ammonium hydroxide Nutrition 0.000 description 10
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 description 8
- DLYUQMMRRRQYAE-UHFFFAOYSA-N phosphorus pentoxide Inorganic materials O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 6
- 229910052698 phosphorus Inorganic materials 0.000 description 6
- 239000011574 phosphorus Substances 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- XLYOFNOQVPJJNP-ZSJDYOACSA-N heavy water Substances [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 5
- 238000003860 storage Methods 0.000 description 5
- 238000011282 treatment Methods 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229910021532 Calcite Inorganic materials 0.000 description 3
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 3
- 239000000920 calcium hydroxide Substances 0.000 description 3
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 3
- 230000003247 decreasing effect Effects 0.000 description 3
- 239000010459 dolomite Substances 0.000 description 3
- 229910000514 dolomite Inorganic materials 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Inorganic materials [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 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 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-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
- 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
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- INIZPXBLAMXMBJ-UHFFFAOYSA-O azanium;magnesium;nitrate Chemical compound [NH4+].[Mg].[O-][N+]([O-])=O INIZPXBLAMXMBJ-UHFFFAOYSA-O 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 230000029087 digestion Effects 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- -1 phosphate radical ions Chemical class 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- MXZRMHIULZDAKC-UHFFFAOYSA-L ammonium magnesium phosphate Chemical compound [NH4+].[Mg+2].[O-]P([O-])([O-])=O MXZRMHIULZDAKC-UHFFFAOYSA-L 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
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- 229910052796 boron Inorganic materials 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
- 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
- 230000007547 defect Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000003912 environmental pollution 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
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052742 iron Inorganic materials 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
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 description 1
- 229910000021 magnesium carbonate Inorganic materials 0.000 description 1
- GVALZJMUIHGIMD-UHFFFAOYSA-H magnesium phosphate Chemical compound [Mg+2].[Mg+2].[Mg+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O GVALZJMUIHGIMD-UHFFFAOYSA-H 0.000 description 1
- 235000010994 magnesium phosphates Nutrition 0.000 description 1
- 229910052943 magnesium sulfate Inorganic materials 0.000 description 1
- 235000019341 magnesium sulphate Nutrition 0.000 description 1
- 229910021645 metal ion Inorganic materials 0.000 description 1
- 238000005065 mining 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
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 125000002467 phosphate group Chemical group [H]OP(=O)(O[H])O[*] 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 150000003254 radicals Chemical class 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 239000004328 sodium tetraborate Substances 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 229910052567 struvite Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 239000011573 trace mineral Substances 0.000 description 1
- 235000013619 trace mineral Nutrition 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
- 238000003828 vacuum filtration Methods 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 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
- C01F5/00—Compounds of magnesium
- C01F5/02—Magnesia
-
- 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
Abstract
The invention provides a method for preparing magnesium oxide and calcium ammonium nitrate by using a chemical mineral separation byproduct, which takes middle-low grade phosphorite as a raw material, prepares low-magnesium phosphate concentrate after crushing, calcining, digesting, leaching and filter-pressing separation, and concentrates calcium-magnesium-containing leaching solution discharged by a filter press to obtain calcium-magnesium ammonium nitrate concentrated solution with the concentration of more than 40 percent; introducing ammonia gas into the concentrated solution of calcium magnesium ammonium nitrate to carry out a magnesium removal reaction; filtering and washing the slurry after magnesium removal, and concentrating and granulating the filtered filtrate to obtain calcium ammonium nitrate; re-slurry washing is carried out on the washed filter cake, and the filter cake after re-slurry washing is dried and calcined to obtain a magnesium oxide product; the method takes the calcium magnesium ammonium nitrate concentrated solution as the raw material to prepare and obtain calcium ammonium nitrate and magnesium oxide, realizes calcium and magnesium separation, effectively solves the problems that the magnesium-containing calcium carbonate mixture has low utilization value, high actual production difficulty, unstable product content, no demand in the produced magnesium-containing calcium carbonate market and the like, generates no waste, and improves the added value of calcium and magnesium elements in the phosphorite.
Description
Technical Field
The invention relates to the technical field of chemical beneficiation by-product treatment, in particular to a method for preparing magnesium oxide and calcium ammonium nitrate from 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, the middle-low grade phosphorite or phosphate tailing is calcined at the temperature of 900-; 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 defects in the technology, the invention provides the method for preparing the magnesium oxide and the calcium ammonium nitrate from the chemical beneficiation by-product, the magnesium oxide and the calcium ammonium nitrate are prepared from the chemical beneficiation by-product through the simplest process flow, the calcium and magnesium separation is realized, and the problems of comprehensive utilization of middle 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 the calcium and magnesium leaching solution in chemical beneficiation are respectively extracted, so that the problems that calcium and magnesium are generally leached twice in the conventional phosphorite treatment and are respectively synthesized and separated, the required washing amount is large, and the operation is complex are solved, and the utilization rate of a calcium and magnesium product mixture is improved through repulping and washing.
In order to achieve the aim, the invention provides a method for preparing magnesium oxide and calcium ammonium nitrate by using a chemical beneficiation byproduct, which comprises the following steps:
taking middle-low grade phosphorite as a raw material, crushing, calcining, digesting, leaching, filter-pressing and separating, and concentrating calcium and magnesium contained leaching solution discharged by filter-pressing and separating to obtain calcium and magnesium ammonium nitrate concentrated solution with the concentration of more than 40%;
introducing ammonia gas into the concentrated solution of calcium magnesium ammonium nitrate to carry out a magnesium removal reaction;
filtering and washing the slurry after magnesium removal, and concentrating and granulating the filtered filtrate to obtain calcium ammonium nitrate; and (4) re-pulping and washing the washed filter cake, and drying and calcining the re-pulped and washed filter cake to obtain the magnesium oxide product.
Preferably, the method comprises the following steps: the crushing comprises crushing the middle-low grade phosphorite to particle size of less than or equal to 4.5mm, the calcining 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 and separation2O5≥34.5%wt、MgO≤0.85%wt low magnesium phosphate concentrate.
Specifically, the method comprises the following steps: the calcium and magnesium containing leaching solution discharged by filter pressing separation is concentrated, and a concentration system adopts a two-effect countercurrent evaporation device.
Preferably, the method comprises the following steps: in the step of the magnesium removal reaction, the reaction temperature is controlled between 10 ℃ and 50 ℃, and the reaction time is controlled between 1h and 3 h.
Specifically, the method comprises the following steps: in the step of drying and calcining to obtain the magnesium oxide product, the filter cake after repulping and washing is firstly dried to obtain magnesium hydroxide, and the magnesium hydroxide is calcined to obtain magnesium oxide.
Specifically, the method comprises the following steps: in the step of concentrating and granulating, the filtrate is sent to a preheater for preheating and then sent to a heat exchanger for heat exchange, the filtrate is sent to an evaporator for evaporation after passing through the heat exchanger, the evaporated filtrate is sent to a separator for separation and then sent to a granulating feeding groove, and the filtrate is sent to a granulator for granulation after heat exchange, and then is cooled, screened and wrapped to obtain the calcium ammonium nitrate.
Preferably, the method comprises the following steps: the preheater adopts condensate generated by medium-pressure steam as a heating medium; the heat exchanger adopts the evaporated filtrate as a heating medium; the evaporator is a forced circulation evaporator; the separator is a flash separator; the granulator is one of a rotary drum fluidized bed granulator, a tower granulator, a slurry spraying granulator, a disc granulator and a steel belt granulator.
Preferably, the method comprises the following steps: the evaporation temperature in the evaporator is 160-180 ℃.
Preferably, the method comprises the following steps: after the filtrate is sent to an evaporator for evaporation after passing through a heat exchanger, the concentrated solution is cooled to the granulation temperature of 100-120 ℃ after heat exchange with the feed liquid to be evaporated through the heat exchanger.
Preferably, the method comprises the following steps: the condensate generated in the concentration step is sent to a filtration washing step for washing.
The invention has the beneficial effects that: compared with the prior art, the method for preparing the magnesium oxide and the calcium ammonium nitrate by the chemical beneficiation by-product comprises the following steps: taking middle-low grade phosphorite as a raw material, preparing low-magnesium phosphate concentrate after crushing, calcining, digesting, leaching and filter pressing separation, and concentrating calcium-magnesium-containing leaching solution discharged from a filter press to obtain calcium-magnesium ammonium nitrate concentrated solution with the concentration of more than 40%; introducing ammonia gas into the concentrated solution of calcium magnesium ammonium nitrate to carry out a magnesium removal reaction; filtering and washing the slurry after magnesium removal, and concentrating and granulating the filtered filtrate to obtain calcium ammonium nitrate; re-slurry washing is carried out on the washed filter cake, and the filter cake after re-slurry washing is dried and calcined to obtain a magnesium oxide product; the method takes the calcium magnesium ammonium nitrate concentrated solution prepared from the mineral separation by-product of the medium-low grade phosphorite as the raw material to prepare and obtain calcium ammonium nitrate and magnesium oxide, thereby realizing calcium-magnesium separation, and effectively solving the problems that the magnesium-containing calcium carbonate mixture obtained in the prior art has low utilization value, the application range is greatly limited, the actual production difficulty is high, the filtrate conversion rate is low, the product content is unstable, and the magnesium-containing calcium carbonate produced at present cannot be digested.
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 schematic diagram 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%.
Specifically, the invention provides a method for preparing magnesium oxide and calcium ammonium nitrate from by-products of chemical beneficiation, referring to fig. 1, the method comprises: taking middle-low grade phosphorite as a raw material, crushing, calcining, digesting, leaching, filter-pressing and separating, and concentrating calcium and magnesium contained leaching solution discharged by filter-pressing and separating to obtain calcium and magnesium ammonium nitrate concentrated solution with the concentration of more than 40%;
introducing ammonia gas into the concentrated solution of calcium magnesium ammonium nitrate to carry out a magnesium removal reaction;
filtering and washing the slurry after magnesium removal, and concentrating and granulating the filtered filtrate to obtain calcium ammonium nitrate; re-slurry washing is carried out on the washed filter cake, and the filter cake after re-slurry washing is dried and calcined to obtain a magnesium oxide product; in this example, the medium and low grade phosphate ore is first crushed, calcined, digested, leached, filter-pressed and separated to prepare P2O5The low-magnesium phosphate concentrate with MgO not more than 34.5 percent and MgO not more than 0.85 percent comprises the following steps: the crushing comprises crushing the middle-low grade phosphorite to particle size of 4.5mm or less, calcining at 900-2O5Low-magnesium phosphate concentrate with the weight percent of more than or equal to 34.5 percent and MgO less than or equal to 0.85 percent; firstly, crushing and grinding the raw materials into fine powder, calcining the fine powder at the calcining temperature of 900-1000 ℃ for 1-1.5h to pyrolyze dolomite and calcite embedded in phosphate ore (simultaneously remove organic matters in the dolomite and the calcite), wherein the main chemical reaction is as follows:
ＣａＣＯ３·ＭｇＣＯ３→ＣａＯ＋ＭｇＯ＋２ＣＯ２↑
ＣａＣＯ３→ＣａＯ＋ＣＯ２↑
Ｃ＋Ｏ２→ＣＯ２
NH for calcined material４ＮＯ３The solution leaches CaO and MgO in the solution by controlling the reaction temperature, leaching time and NH４ＮＯ３The CaO and MgO in the calcined material can be basically removed under the conditions of solution concentration, liquid-solid ratio and the like, and the main chemical reactions are as follows:
ＣａＯ＋ＭｇＯ＋２Ｈ２Ｏ→Ｃａ（ＯＨ）２＋Ｍｇ（ＯＨ）２
by means of NH４ＮＯ３The characteristic of dissolving calcium and magnesium is that Ca (OH) generated after pyrolysis digestion is preferentially used２、Ｍｇ（ＯＨ）２Dissolving to generate Ca (NO)３）２、Ｍｇ（ＮＯ３）２，
The main chemical reactions are:
Ｃａ（ＯＨ）２＋２ＮＨ４ＮＯ３→Ｃａ（ＮＯ３）２＋２ＮＨ３↑＋２Ｈ２Ｏ
Ｍｇ（ＯＨ）２＋２ＮＨ４ＮＯ３→Ｍｇ（ＮＯ３）２＋２ＮＨ３↑＋２Ｈ２Ｏ
NH4NO3the mass fraction of the solution for leaching calcium and magnesium is controlled to be 17-30%, and the ratio of the solution to the calcium and magnesium to be removed is (2.1-2.3): 1, the liquid-solid ratio is (4-7): 1, the removal rate of calcium and magnesium can reach more than 96 percent under the condition, the MgO in the phosphate concentrate can be ensured to be less than or equal to 0.85 percent, and the P content can be ensured to be less than or equal to P2O5≥34.5%；
The leaching time is controlled to be 90-95 ℃ so as to be beneficial to leaching calcium and magnesium; the leaching time is controlled at 120-300min, so that the calcium and magnesium leaching rate can be ensured, and the energy consumption can be saved. And after the low-magnesium phosphate concentrate is prepared in the filter-pressing separation process, the filter press discharges the residual leaching solution containing calcium and magnesium elements.
In this embodiment: the calcium and magnesium containing leachate discharged by filter pressing separation is concentrated, a concentration system adopts a two-effect countercurrent evaporation device, and the two-effect countercurrent evaporation device is an evaporation operation in which two evaporators are connected in series to run, so that steam heat energy is utilized for multiple times, the heat energy utilization rate is improved, and the calcium and magnesium containing leachate is mainly used for aqueous solution treatment; in the process of the two-effect evaporation operation, the first evaporator (called as a first effect) takes the raw steam as the heating steam, and the second effect takes the secondary steam of the previous effect as the heating steam, so that the consumption of the raw steam can be reduced; the temperature of the secondary steam is always lower than that of the heating steam, so that the operating pressure of each effect and the boiling temperature of the solution are sequentially reduced along the flow direction of the steam during the two-effect evaporation.
Specifically, when a calcium magnesium ammonium nitrate concentrated solution with the concentration of more than 40% is prepared, a certain amount of water or washing liquor is added into calcined mineral powder to prepare a 40% slurry, 30% ammonium nitrate solution is gradually added, nitric acid is added after reaction for 1 hour to adjust the pH of the slurry, the reaction temperature is controlled to be 80 ℃, the reaction time is 2 hours, after the reaction is finished, filtration is carried out, a filter cake is phosphate concentrate, filtrate is sent to a two-effect countercurrent evaporation device to be concentrated to obtain the calcium magnesium nitrate concentrated solution with the concentration of more than 40%, condensate generated by a concentration system is returned to each filtration step to be reused, the utilization rate is increased, and waste is reduced. Or slowly adding a certain amount of calcium hydroxide into the filtrate, adjusting the pH value to 6.8, controlling the time to be 60min, stirring at the speed of 300rpm, filtering again after the reaction is finished, concentrating and crystallizing the filtrate, controlling the concentration temperature to be 90 ℃ and carrying out vacuum concentration until a large amount of crystals appear, drying the crystals in a drying oven at the drying temperature of 98 ℃ for 3h to obtain the calcium magnesium ammonium nitrate crystal fertilizer.
In this embodiment: in the step of magnesium removal and pulping, the reaction temperature is controlled between 10 ℃ and 50 ℃, and the reaction time is controlled between 1h and 3 h; specifically, the calcium magnesium nitrate concentrated solution is placed in a neutralization tank, ammonia water or ammonia gas is introduced, the pH value is adjusted, when the pH value of the first-step neutralization reaction is reached, the solution is stirred in the neutralization tank for a period of time, the obtained slurry is subjected to vacuum filtration, the obtained slurry and the ammonia water or ammonia gas introduced into the tank reactor are subjected to a second-step neutralization reaction, when a certain pH value is reached, the introduction of the ammonia water or ammonia gas is stopped, and the reaction is continued for a period of time.
Specifically, ammonia water is introduced to perform a first-step neutralization impurity removal reaction to generate magnesium ammonium phosphate, and the main chemical reaction is as follows:
Ｍｇ２＋ ＋ ＮＨ４ ＋ ＋ ＰＯ４ ３－ ＝ ＮＨ４ＭｇＰＯ４↓
then ammonia water is introduced for carrying out the second-step neutralization reaction to generate the product magnesium hydroxide:
Ｍｇ２＋ ＋２ＮＨ３＋２Ｈ２Ｏ＝Ｍｇ（ＯＨ）２↓＋２ＮＨ４ ＋
in this embodiment: in the step of drying and calcining to obtain the magnesium oxide product, the filter cake after pulp washing is firstly dried to obtain the hydrogen and oxygenMagnesium oxide is obtained by calcining magnesium hydroxide; the crystal shape of the magnesium hydroxide is hexagonal crystal form or amorphous, the magnesium hydroxide is decomposed into magnesium oxide and water at 350 ℃, the magnesium oxide and the water are directly dehydrated to be changed into the magnesium oxide when the temperature is increased to 500 ℃, and the specific chemical reaction is as follows: mg (OH)2→MgO+H2O; the leaching solution after the magnesium removal of the phosphorite contains a certain amount of magnesium sulfate, phosphate radical ions and some metal ions, if the waste liquid is directly discharged, the environment is polluted, and magnesium elements in the waste liquid are wasted.
In this embodiment: in the step of concentration and granulation, filtrate is sent to a preheater for preheating and then sent to a heat exchanger for heat exchange, the filtrate is sent to an evaporator for evaporation after passing through the heat exchanger, the evaporated filtrate is sent to a separator for separation and then sent to a granulation feeding groove, and after heat exchange, the filtrate is sent to a granulator for granulation and then is cooled, screened and wrapped to obtain calcium ammonium nitrate; specifically, the main component in the filtrate is Ca (NO)3）2、NH4NO3And part of trace elements, the calcium nitrate generated in the solution state is its hydrate Ca (NO)3）2·4H2O (containing N11%) is heated to 40 deg.C and 2H molecules are released2O, Ca (NO) formed at a given temperature3）2·2H2O (containing N13%), further heating to 150 deg.C, and dewatering to obtain Ca (NO)3）2And contains N18%. For granulation, the filtrate may contain NH when the calcium nitrate slurry is concentrated to 60%4NO3，NH4NO3As additive, the product containing N20-25.5% is produced. The calcium nitrate is stable to heat and only decomposes at high temperature (561 ℃), if a secondary element water-soluble fertilizer is to be produced, concentrated filtrate A is sent to a melting tank after heat exchange through a heat exchanger, metered solution containing boron and zinc is added, and the mixture is sent to a granulator for granulation after the temperature is reduced to 100-120 ℃.
One preferred embodiment mentions: the preheater adopts condensate generated by medium-pressure steam as a heating medium; the heat exchanger adopts the evaporated filtrate as a heating medium; the evaporator is a forced circulation type evaporator; the separator is a flash separator; the granulator is one of a rotary drum fluidized bed granulator, a tower granulator, a slurry spraying granulator, a disc granulator and a steel belt granulator.
One preferred embodiment mentions: the evaporation temperature in the evaporator is 160-180 ℃.
One preferred embodiment mentions: after the filtrate passes through a heat exchanger and is sent to an evaporator for evaporation, the temperature of the filtrate is reduced to 100-120 ℃.
One preferred embodiment mentions: the condensate produced in the concentration step is sent to the filtration washing step for washing.
In a specific example 1:
(1) separating the medium and low grade phosphate ores by a filter press to discharge calcium and magnesium containing leaching solution;
(2) conveying the calcium-containing magnesium leaching solution obtained in the step (1) to a concentration system for first concentration to obtain a calcium magnesium nitrate concentrated solution with the concentration of more than 40%;
(3) under the condition that the temperature is 50 ℃, adding ammonia water into the calcium magnesium nitrate concentrated solution in the step (3) and adjusting the pH value to be 11, wherein the dropping speed of the ammonia water is 1.5ml/min, the settling time is 100min, and carrying out a magnesium removal reaction to obtain a magnesium removal feed liquid, wherein the recovery rate of magnesium is 90.12%;
(4) filtering the magnesium-removed liquid in the step (3) in a vacuum filter to obtain a filtrate A and a filter cake B;
(5) and (4) washing the filter cake B in the step (4), then carrying out slurry washing and drying to obtain a magnesium hydroxide product, carrying out slurry washing at the temperature of 65 ℃, drying and calcining the filter cake at the temperature of 635 ℃ to obtain magnesium oxide with the mass fractions of MgO95.23% and CaO0.24%.
(6) And (5) carrying out second concentration on the filtrate A in the step (4): preheating the filtrate A, putting the preheated filtrate A into a heat exchanger for heat exchange, putting into a forced circulation type evaporator for evaporation, and carrying out gas-liquid separation on the filtrate A under the condition that the temperature of the filtrate A reaches 160 ℃ to obtain a concentrated solution;
(7) and (4) feeding the concentrated solution obtained in the step (6) into a granulation feeding groove, granulating by using a rotary drum fluidized bed granulator, cooling, screening and wrapping to obtain a calcium ammonium nitrate product containing 15.54% of N and 18.52% of Ca18.
In a specific example 2:
(1) separating the medium and low grade phosphate ores by a filter press to discharge calcium and magnesium containing leaching solution;
(2) conveying the calcium-containing magnesium leaching solution obtained in the step (1) to a concentration system for first concentration to obtain a calcium magnesium nitrate concentrated solution with the concentration of more than 40%;
(3) adding ammonia water into the calcium magnesium nitrate concentrated solution in the step (3) at the temperature of 40 ℃ to precipitate magnesium therein, wherein the main chemical reaction is as follows:
Ｍｇ（ＮＯ３）２＋2ＮＨ3.H2O→Ｍｇ（ＯＨ）２↓＋２ＮＨ４ＮＯ３
adjusting the pH value, wherein the pH value of the neutralization reaction in the first step is 10, the pH value of the neutralization reaction in the second step is 9.25, the dropping speed of ammonia water is 1.8ml/min, the settling time is 60min, and performing a magnesium removal process to obtain a magnesium removal liquid;
(4) filtering the magnesium-removed liquid in the step (3) in a vacuum filter to obtain a filtrate A and a filter cake B;
(5) washing the filter cake B in the step (4), then washing the filter cake B by pulp, drying the filter cake B at the temperature of 80 ℃ to obtain a magnesium hydroxide product, and calcining the magnesium hydroxide product at the temperature of 650 ℃ to obtain a magnesium oxide product, wherein the MgO composition obtained in the step (5) is shown in the following table:
| MgＯ | CaO≤ | iron ion is less than or equal to | Chloride is less than or equal to | Loss on ignition | |
| Mass fraction | 99.7 | 0.0940 | 0.0040 | 0.0040 | 25 |
(6) And (5) carrying out second concentration on the filtrate A in the step (4): preheating the filtrate A, putting the preheated filtrate A into a heat exchanger for heat exchange, putting into a forced circulation type evaporator for evaporation, and carrying out gas-liquid separation on the filtrate A under the condition that the temperature of the filtrate A reaches 160 ℃ to obtain a concentrated solution;
(7) and (4) feeding the concentrated solution obtained in the step (6) into a granulation feeding groove, granulating by a rotary drum fluidized bed granulator, cooling, screening and wrapping to obtain a calcium ammonium nitrate product containing 16.08 percent of N and 18.85 percent of Cao.
In one specific example 3:
(1) separating the medium and low grade phosphate ores by a filter press to discharge calcium and magnesium containing leaching solution;
(2) conveying the calcium-containing magnesium leaching solution obtained in the step (1) to a concentration system for first concentration to obtain a calcium magnesium nitrate concentrated solution with the concentration of more than 40%;
(3) under the condition that the temperature is 30 ℃, adding ammonia water into the calcium magnesium nitrate concentrated solution in the step (3) and adjusting the pH value, controlling the pH value at the end point of the neutralization reaction in the first step to be 9.3, controlling the pH value range at the end point of the neutralization reaction in the second step to be 10.25, and controlling the time of the neutralization reaction in the second step to be 45 min, preparing magnesium removal solutions with different mass concentrations to ensure that the mass concentrations of MgO are 0.002, 0.004, 0.005, 0.007, 0.010 and 0.02 g/ml, and obtaining results of the reaction under different mass concentrations as shown in the following table;
(4) filtering the magnesium-removed liquid in the step (3) in a vacuum filter to obtain a filtrate A and a filter cake B;
| mass concentration of MgO | 0.002 | 0.004 | 0.005 | 0.007 | 0.010 | 0.02 |
| Reaction time | 45 min | 45 min | 45 min | 45 min | 45 min | 45 min |
| Mass fraction of magnesium hydroxide | 95.32% | 96.14% | 97.12% | 99.58% | 97.01% | 96.47% |
As can be seen from Table 1, when the mass concentration of MgO in the magnesium removal solution is gradually increased, the mass fraction of magnesium hydroxide in the magnesium removal solution is increased and then decreased, and reaches the maximum value at 0.007 g/mL, and when the mass concentration of MgO in the magnesium removal waste solution is continuously increased, the mass fraction of magnesium hydroxide in the magnesium removal solution is gradually decreased, and the yield of magnesium oxide is decreased along with the increase of the mass concentration of MgO in the magnesium removal waste solution.
(5) And (3) washing the filter cake B in the step (4), then carrying out pulp washing again, wherein the pulp washing temperature is 180 ℃, drying to obtain a magnesium hydroxide product, comprehensively considering that the mass concentration of MgO in the magnesium removal liquid is preferably 0.007 g/mL, the mass fraction of the magnesium hydroxide is higher than 99.58%, and then calcining the magnesium hydroxide at 700 ℃ to obtain magnesium oxide products with the mass fractions of MgO95.68% and CaO0.13%.
(6) And (5) carrying out second concentration on the filtrate A in the step (4): preheating the filtrate A, putting the preheated filtrate A into a heat exchanger for heat exchange, putting into a forced circulation type evaporator for evaporation, and carrying out gas-liquid separation on the filtrate A under the condition that the temperature of the filtrate A reaches 160 ℃ to obtain a concentrated solution;
(7) and (3) feeding the concentrated solution obtained in the step (6) into a granulation feeding groove, adding 1% of borax and 0.5% of zinc nitrate as auxiliary materials, melting, granulating by a rotary drum fluidized bed granulator, a disc granulator or a slurry spraying granulator and the like, cooling, screening and packaging to obtain a calcium ammonium nitrate product containing 16.12% of N, 18.68% of Cao, 0.11% of B and 0.12% of Zno.
The invention has the advantages that:
the method takes middle-low grade phosphorite as a raw material, and the calcium magnesium ammonium nitrate concentrated solution with the concentration of more than 40 percent is obtained by concentrating the calcium magnesium containing leaching solution discharged after crushing, calcining, digesting, leaching and filter pressing separation; introducing ammonia gas into the concentrated solution of calcium magnesium ammonium nitrate to remove magnesium and form slurry; filtering and washing the slurry after magnesium removal, and concentrating and granulating the filtered filtrate to obtain calcium ammonium nitrate; re-slurry washing is carried out on the washed filter cake, and the filter cake after re-slurry washing is dried and calcined to obtain a magnesium oxide product; the method takes the calcium magnesium ammonium nitrate concentrated solution prepared from the mineral separation by-products of the medium-grade and low-grade phosphorite as the raw material to prepare and obtain calcium ammonium nitrate and magnesium oxide, thereby realizing calcium and magnesium separation and effectively solving the problems that the magnesium-containing calcium carbonate mixture obtained in the prior art has lower utilization value, large actual production difficulty, unstable product content, indigestibility of the produced magnesium-containing calcium carbonate and the like.
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 preparing magnesium oxide and calcium ammonium nitrate by using a chemical beneficiation byproduct is characterized by comprising the following steps:
taking middle-low grade phosphorite as a raw material, preparing low-magnesium phosphate concentrate after crushing, calcining, digesting, leaching and filter pressing separation, and concentrating calcium-magnesium-containing leaching solution discharged from a filter press to obtain calcium-magnesium ammonium nitrate concentrated solution with the concentration of more than 40%;
introducing ammonia gas into the concentrated solution of calcium magnesium ammonium nitrate to carry out a magnesium removal reaction;
filtering and washing the slurry after magnesium removal, and concentrating and granulating the filtered filtrate to obtain calcium ammonium nitrate; and (4) re-pulping and washing the washed filter cake, and drying and calcining the re-pulped and washed filter cake to obtain the magnesium oxide product.
2. The method for preparing magnesium oxide and calcium ammonium nitrate from by-products of chemical mineral separation according to claim 1, wherein the crushing comprises crushing middle-low grade phosphate ore to particle size of 4.5mm or less, the calcining temperature is 900-2O5The low-magnesium phosphate concentrate is more than or equal to 34.5 wt% and MgO is less than or equal to 0.85 wt%.
3. The method for preparing magnesium oxide and calcium ammonium nitrate from the by-products of chemical mineral separation according to claim 1, characterized in that the leaching solution containing calcium and magnesium discharged by filter-pressing separation is concentrated, and a concentration system adopts a two-effect counter-current evaporation device.
4. The method for preparing magnesium oxide and calcium ammonium nitrate by using the chemical beneficiation byproduct according to claim 1, wherein in the magnesium removal reaction step, the reaction temperature is controlled to be between 10 ℃ and 50 ℃, and the reaction time is controlled to be between 1h and 3 h.
5. The method for preparing magnesium oxide and calcium ammonium nitrate from the by-products of chemical beneficiation according to claim 1, wherein in the step of drying and calcining to obtain the magnesium oxide product, the filter cake after repulping and washing is firstly dried to obtain magnesium hydroxide, and then the magnesium hydroxide is calcined to obtain magnesium oxide.
6. The method for preparing magnesium oxide and calcium ammonium nitrate from byproducts of chemical mineral separation according to claim 1, characterized in that in the step of concentration and granulation, filtrate is sent to a preheater for preheating and then sent to a heat exchanger for heat exchange, the filtrate is sent to an evaporator for evaporation after heat exchange through the heat exchanger, the evaporated filtrate is sent to a separator for separation and then sent to a granulation feeding tank, and the filtrate is sent to a granulator for granulation, cooling, screening and wrapping after heat exchange to obtain calcium ammonium nitrate.
7. The method for preparing magnesium oxide and calcium ammonium nitrate from the chemical beneficiation by-product according to claim 6, wherein the preheater adopts condensate generated by medium-pressure steam as a heating medium; the heat exchanger adopts the evaporated feed liquid as a heating medium; the evaporator is a forced circulation evaporator; the separator is a flash separator; the granulator is one of a rotary drum fluidized bed granulator, a tower granulator, a slurry spraying granulator, a disc granulator and a steel belt granulator.
8. The method for preparing magnesium oxide and calcium ammonium nitrate from the by-product of chemical beneficiation according to claim 6, wherein the evaporation temperature in the evaporator is 160 ℃ to 180 ℃.
9. The method for preparing magnesium oxide and calcium ammonium nitrate from the byproducts of chemical beneficiation according to claim 6, wherein after the filtrate passes through a heat exchanger and is sent to an evaporator for evaporation, the concentrated solution is cooled to the granulation temperature of 100-120 ℃ after heat exchange with the feed liquid to be evaporated through the heat exchanger.
10. The method for preparing magnesium oxide and calcium ammonium nitrate from the by-product of chemical beneficiation according to claim 1, wherein the condensate generated in the concentration step is sent to a filtration washing step for washing.
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| CN110304947A (en) * | 2019-08-15 | 2019-10-08 | 贵州芭田生态工程有限公司 | Calcium ammonium nitrate magnesium granules fertilizer and preparation method thereof |
| CN111186850A (en) * | 2019-12-27 | 2020-05-22 | 南京宝淳新材料科技有限公司 | Magnesium oxide for oriented silicon steel annealing separant and preparation method thereof |
| CN111498820A (en) * | 2020-04-26 | 2020-08-07 | 贵州省化工研究院 | Process for simultaneously preparing high-quality calcium sulfate whiskers from phosphorus concentrate enriched by medium-low-grade phosphate ore or phosphorus tailings |
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Application publication date: 20210430 |