EP0648198A1 - A process for modifying particulate solids and particulate solids prepared thereby - Google Patents
A process for modifying particulate solids and particulate solids prepared therebyInfo
- Publication number
- EP0648198A1 EP0648198A1 EP93914848A EP93914848A EP0648198A1 EP 0648198 A1 EP0648198 A1 EP 0648198A1 EP 93914848 A EP93914848 A EP 93914848A EP 93914848 A EP93914848 A EP 93914848A EP 0648198 A1 EP0648198 A1 EP 0648198A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- salt
- reaction product
- water soluble
- particulate solid
- water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
- 238000000034 method Methods 0.000 title claims abstract description 43
- 239000007787 solid Substances 0.000 title claims abstract description 42
- 230000008569 process Effects 0.000 title claims abstract description 39
- 150000003839 salts Chemical class 0.000 claims abstract description 102
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 100
- 239000003153 chemical reaction reagent Substances 0.000 claims abstract description 44
- 239000007795 chemical reaction product Substances 0.000 claims abstract description 35
- 150000002500 ions Chemical class 0.000 claims abstract description 30
- 229910017053 inorganic salt Inorganic materials 0.000 claims abstract description 29
- 238000004090 dissolution Methods 0.000 claims abstract description 18
- 239000007864 aqueous solution Substances 0.000 claims abstract description 17
- 229910019142 PO4 Inorganic materials 0.000 claims abstract description 16
- 235000021317 phosphate Nutrition 0.000 claims abstract description 16
- 150000003013 phosphoric acid derivatives Chemical class 0.000 claims abstract description 14
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims abstract description 13
- 150000002823 nitrates Chemical class 0.000 claims abstract description 12
- 150000004820 halides Chemical class 0.000 claims abstract description 11
- 230000007423 decrease Effects 0.000 claims abstract description 10
- 238000000576 coating method Methods 0.000 claims description 64
- 239000011248 coating agent Substances 0.000 claims description 54
- 239000002245 particle Substances 0.000 claims description 32
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical group [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 claims description 21
- 150000001768 cations Chemical class 0.000 claims description 10
- 239000011575 calcium Substances 0.000 claims description 9
- 229910052748 manganese Inorganic materials 0.000 claims description 9
- 229910052802 copper Inorganic materials 0.000 claims description 8
- 229910052742 iron Inorganic materials 0.000 claims description 8
- 229910052725 zinc Inorganic materials 0.000 claims description 8
- 229910052750 molybdenum Inorganic materials 0.000 claims description 7
- 229910052700 potassium Inorganic materials 0.000 claims description 7
- 239000011785 micronutrient Substances 0.000 claims description 6
- 235000013369 micronutrients Nutrition 0.000 claims description 6
- 239000004094 surface-active agent Substances 0.000 claims description 6
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 5
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 4
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical group [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 claims description 4
- 239000011591 potassium Substances 0.000 claims description 4
- 229910020440 K2SiF6 Inorganic materials 0.000 claims description 3
- 239000001506 calcium phosphate Substances 0.000 claims description 3
- 229910000389 calcium phosphate Inorganic materials 0.000 claims description 3
- 235000011010 calcium phosphates Nutrition 0.000 claims description 3
- 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 claims description 3
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 2
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 claims description 2
- 229910001634 calcium fluoride Inorganic materials 0.000 claims description 2
- QXDMQSPYEZFLGF-UHFFFAOYSA-L calcium oxalate Chemical compound [Ca+2].[O-]C(=O)C([O-])=O QXDMQSPYEZFLGF-UHFFFAOYSA-L 0.000 claims description 2
- GUPPESBEIQALOS-UHFFFAOYSA-L calcium tartrate Chemical compound [Ca+2].[O-]C(=O)C(O)C(O)C([O-])=O GUPPESBEIQALOS-UHFFFAOYSA-L 0.000 claims description 2
- 239000001427 calcium tartrate Substances 0.000 claims description 2
- 235000011035 calcium tartrate Nutrition 0.000 claims description 2
- HIAAVKYLDRCDFQ-UHFFFAOYSA-L calcium;dodecanoate Chemical compound [Ca+2].CCCCCCCCCCCC([O-])=O.CCCCCCCCCCCC([O-])=O HIAAVKYLDRCDFQ-UHFFFAOYSA-L 0.000 claims description 2
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 229910052698 phosphorus Inorganic materials 0.000 claims description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims 2
- 229910003202 NH4 Inorganic materials 0.000 claims 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims 1
- 239000012736 aqueous medium Substances 0.000 claims 1
- 239000011574 phosphorus Substances 0.000 claims 1
- 235000002639 sodium chloride Nutrition 0.000 description 80
- 239000003337 fertilizer Substances 0.000 description 36
- 238000006243 chemical reaction Methods 0.000 description 12
- 239000000243 solution Substances 0.000 description 12
- -1 NH. Substances 0.000 description 11
- 239000000203 mixture Substances 0.000 description 9
- 239000004323 potassium nitrate Substances 0.000 description 9
- 235000010333 potassium nitrate Nutrition 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- 238000011282 treatment Methods 0.000 description 8
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 7
- 239000002253 acid Substances 0.000 description 7
- 235000015097 nutrients Nutrition 0.000 description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 239000002904 solvent Substances 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 239000010949 copper Substances 0.000 description 5
- 239000008187 granular material Substances 0.000 description 5
- 239000011572 manganese Substances 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 239000002689 soil Substances 0.000 description 5
- 239000011701 zinc Substances 0.000 description 5
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 4
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 4
- 150000001412 amines Chemical class 0.000 description 4
- 238000009472 formulation Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 235000021049 nutrient content Nutrition 0.000 description 4
- 239000011780 sodium chloride Substances 0.000 description 4
- 150000003863 ammonium salts Chemical class 0.000 description 3
- 150000001450 anions Chemical class 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 3
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Inorganic materials [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 239000000470 constituent Substances 0.000 description 3
- 229910052602 gypsum Inorganic materials 0.000 description 3
- 239000010440 gypsum Substances 0.000 description 3
- 230000002209 hydrophobic effect Effects 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 150000007524 organic acids Chemical class 0.000 description 3
- 239000002367 phosphate rock Substances 0.000 description 3
- 229920000642 polymer Polymers 0.000 description 3
- 239000001103 potassium chloride Substances 0.000 description 3
- 235000011164 potassium chloride Nutrition 0.000 description 3
- 230000009467 reduction Effects 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
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 description 2
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000004115 Sodium Silicate Substances 0.000 description 2
- QPZLAIPVODCKBU-UHFFFAOYSA-O [N+](=O)([O-])[O-].[NH4+].[Co] Chemical compound [N+](=O)([O-])[O-].[NH4+].[Co] QPZLAIPVODCKBU-UHFFFAOYSA-O 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- LFVGISIMTYGQHF-UHFFFAOYSA-N ammonium dihydrogen phosphate Chemical compound [NH4+].OP(O)([O-])=O LFVGISIMTYGQHF-UHFFFAOYSA-N 0.000 description 2
- 229910000387 ammonium dihydrogen phosphate Inorganic materials 0.000 description 2
- MXZRMHIULZDAKC-UHFFFAOYSA-L ammonium magnesium phosphate Chemical compound [NH4+].[Mg+2].[O-]P([O-])([O-])=O MXZRMHIULZDAKC-UHFFFAOYSA-L 0.000 description 2
- 229910052925 anhydrite Inorganic materials 0.000 description 2
- 229910000152 cobalt phosphate Inorganic materials 0.000 description 2
- ZBDSFTZNNQNSQM-UHFFFAOYSA-H cobalt(2+);diphosphate Chemical compound [Co+2].[Co+2].[Co+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O ZBDSFTZNNQNSQM-UHFFFAOYSA-H 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 2
- MNNHAPBLZZVQHP-UHFFFAOYSA-N diammonium hydrogen phosphate Chemical compound [NH4+].[NH4+].OP([O-])([O-])=O MNNHAPBLZZVQHP-UHFFFAOYSA-N 0.000 description 2
- 239000000839 emulsion Substances 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 229910000399 iron(III) phosphate Inorganic materials 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 2
- IIPYXGDZVMZOAP-UHFFFAOYSA-N lithium nitrate Chemical compound [Li+].[O-][N+]([O-])=O IIPYXGDZVMZOAP-UHFFFAOYSA-N 0.000 description 2
- MFUVDXOKPBAHMC-UHFFFAOYSA-N magnesium;dinitrate;hexahydrate Chemical compound O.O.O.O.O.O.[Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MFUVDXOKPBAHMC-UHFFFAOYSA-N 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 235000019837 monoammonium phosphate Nutrition 0.000 description 2
- 229910000402 monopotassium phosphate Inorganic materials 0.000 description 2
- 235000019796 monopotassium phosphate Nutrition 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- PJNZPQUBCPKICU-UHFFFAOYSA-N phosphoric acid;potassium Chemical compound [K].OP(O)(O)=O PJNZPQUBCPKICU-UHFFFAOYSA-N 0.000 description 2
- 239000011435 rock Substances 0.000 description 2
- 238000005201 scrubbing Methods 0.000 description 2
- 239000011734 sodium Substances 0.000 description 2
- 229910052708 sodium Inorganic materials 0.000 description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 2
- NTHWMYGWWRZVTN-UHFFFAOYSA-N sodium silicate Chemical compound [Na+].[Na+].[O-][Si]([O-])=O NTHWMYGWWRZVTN-UHFFFAOYSA-N 0.000 description 2
- 229910052911 sodium silicate Inorganic materials 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 230000001988 toxicity Effects 0.000 description 2
- 231100000419 toxicity Toxicity 0.000 description 2
- 239000012808 vapor phase Substances 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 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
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 239000004254 Ammonium phosphate Substances 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 235000010469 Glycine max Nutrition 0.000 description 1
- 244000068988 Glycine max Species 0.000 description 1
- 241000581652 Hagenia abyssinica Species 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- 229910017958 MgNH Inorganic materials 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 1
- RSBNPUNXBGVNNB-UHFFFAOYSA-M S(=O)(=O)([O-])[O-].[NH4+].[Co+] Chemical compound S(=O)(=O)([O-])[O-].[NH4+].[Co+] RSBNPUNXBGVNNB-UHFFFAOYSA-M 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 1
- 229920001807 Urea-formaldehyde Polymers 0.000 description 1
- 238000007259 addition reaction Methods 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 229910000148 ammonium phosphate Inorganic materials 0.000 description 1
- 235000019289 ammonium phosphates Nutrition 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
- 229910001871 ammonium zinc sulfate Inorganic materials 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- YNGQHHUHCOYPKT-UHFFFAOYSA-L azanium;calcium;phosphate Chemical compound [NH4+].[Ca+2].[O-]P([O-])([O-])=O YNGQHHUHCOYPKT-UHFFFAOYSA-L 0.000 description 1
- FCXHHGTWMFGYPP-UHFFFAOYSA-L azanium;cobalt(2+);phosphate Chemical compound [NH4+].[Co+2].[O-]P([O-])([O-])=O FCXHHGTWMFGYPP-UHFFFAOYSA-L 0.000 description 1
- VCNSVJZBSHPMSH-UHFFFAOYSA-N azanium;cobalt;chloride Chemical compound [NH4+].[Cl-].[Co] VCNSVJZBSHPMSH-UHFFFAOYSA-N 0.000 description 1
- JLUGKDWGQPNDGX-UHFFFAOYSA-L azanium;manganese(2+);phosphate Chemical compound [NH4+].[Mn+2].[O-]P([O-])([O-])=O JLUGKDWGQPNDGX-UHFFFAOYSA-L 0.000 description 1
- TZCXTZWJZNENPQ-UHFFFAOYSA-L barium sulfate Inorganic materials [Ba+2].[O-]S([O-])(=O)=O TZCXTZWJZNENPQ-UHFFFAOYSA-L 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- YYRMJZQKEFZXMX-UHFFFAOYSA-L calcium bis(dihydrogenphosphate) Chemical compound [Ca+2].OP(O)([O-])=O.OP(O)([O-])=O YYRMJZQKEFZXMX-UHFFFAOYSA-L 0.000 description 1
- 229940062672 calcium dihydrogen phosphate Drugs 0.000 description 1
- 229960001714 calcium phosphate Drugs 0.000 description 1
- 159000000007 calcium salts Chemical class 0.000 description 1
- CJZGTCYPCWQAJB-UHFFFAOYSA-L calcium stearate Chemical compound [Ca+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CJZGTCYPCWQAJB-UHFFFAOYSA-L 0.000 description 1
- 239000008116 calcium stearate Substances 0.000 description 1
- 235000013539 calcium stearate Nutrition 0.000 description 1
- YYRMJZQKEFZXMX-UHFFFAOYSA-N calcium;phosphoric acid Chemical compound [Ca+2].OP(O)(O)=O.OP(O)(O)=O YYRMJZQKEFZXMX-UHFFFAOYSA-N 0.000 description 1
- XOZREOIZDKNXBN-UHFFFAOYSA-L calcium;potassium;sulfate Chemical compound [K+].[Ca+2].[O-]S([O-])(=O)=O XOZREOIZDKNXBN-UHFFFAOYSA-L 0.000 description 1
- VVJRSSJSRXEOQL-UHFFFAOYSA-N calcium;potassium;sulfuric acid;hydrate Chemical compound O.[K].[K].[Ca].OS(O)(=O)=O.OS(O)(=O)=O VVJRSSJSRXEOQL-UHFFFAOYSA-N 0.000 description 1
- 239000004202 carbamide Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 239000004568 cement Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000005352 clarification Methods 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 239000010883 coal ash Substances 0.000 description 1
- 239000007931 coated granule Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 1
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 description 1
- 229910001981 cobalt nitrate Inorganic materials 0.000 description 1
- MULYSYXKGICWJF-UHFFFAOYSA-L cobalt(2+);oxalate Chemical compound [Co+2].[O-]C(=O)C([O-])=O MULYSYXKGICWJF-UHFFFAOYSA-L 0.000 description 1
- SCNCIXKLOBXDQB-UHFFFAOYSA-K cobalt(3+);2-hydroxypropane-1,2,3-tricarboxylate Chemical compound [Co+3].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O SCNCIXKLOBXDQB-UHFFFAOYSA-K 0.000 description 1
- 239000012612 commercial material Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 229910000153 copper(II) phosphate Inorganic materials 0.000 description 1
- GQDHEYWVLBJKBA-UHFFFAOYSA-H copper(ii) phosphate Chemical compound [Cu+2].[Cu+2].[Cu+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O GQDHEYWVLBJKBA-UHFFFAOYSA-H 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000001723 curing Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- TXGQALXWGNPMKD-UHFFFAOYSA-L diazanium;zinc;disulfate;hexahydrate Chemical compound [NH4+].[NH4+].O.O.O.O.O.O.[Zn+2].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O TXGQALXWGNPMKD-UHFFFAOYSA-L 0.000 description 1
- 235000014113 dietary fatty acids Nutrition 0.000 description 1
- 150000004683 dihydrates Chemical class 0.000 description 1
- ZPWVASYFFYYZEW-UHFFFAOYSA-L dipotassium hydrogen phosphate Chemical compound [K+].[K+].OP([O-])([O-])=O ZPWVASYFFYYZEW-UHFFFAOYSA-L 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- POULHZVOKOAJMA-UHFFFAOYSA-M dodecanoate Chemical compound CCCCCCCCCCCC([O-])=O POULHZVOKOAJMA-UHFFFAOYSA-M 0.000 description 1
- 238000010410 dusting Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000000194 fatty acid Substances 0.000 description 1
- 229930195729 fatty acid Natural products 0.000 description 1
- 150000004665 fatty acids Chemical class 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000005188 flotation Methods 0.000 description 1
- 229910052587 fluorapatite Inorganic materials 0.000 description 1
- 238000005469 granulation Methods 0.000 description 1
- 230000003179 granulation Effects 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 159000000014 iron salts Chemical class 0.000 description 1
- WBJZTOZJJYAKHQ-UHFFFAOYSA-K iron(3+) phosphate Chemical compound [Fe+3].[O-]P([O-])([O-])=O WBJZTOZJJYAKHQ-UHFFFAOYSA-K 0.000 description 1
- 229940070765 laurate Drugs 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 229910001386 lithium phosphate Inorganic materials 0.000 description 1
- 229910003002 lithium salt Inorganic materials 0.000 description 1
- 159000000002 lithium salts Chemical class 0.000 description 1
- AZEPWULHRMVZQR-UHFFFAOYSA-M lithium;dodecanoate Chemical compound [Li+].CCCCCCCCCCCC([O-])=O AZEPWULHRMVZQR-UHFFFAOYSA-M 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- UHNWOJJPXCYKCG-UHFFFAOYSA-L magnesium oxalate Chemical compound [Mg+2].[O-]C(=O)C([O-])=O UHNWOJJPXCYKCG-UHFFFAOYSA-L 0.000 description 1
- 159000000003 magnesium salts Chemical class 0.000 description 1
- JWSMTBMIGYJJJM-UHFFFAOYSA-N magnesium;azane Chemical compound N.[Mg+2] JWSMTBMIGYJJJM-UHFFFAOYSA-N 0.000 description 1
- BJZBHTNKDCBDNQ-UHFFFAOYSA-L magnesium;dodecanoate Chemical compound [Mg+2].CCCCCCCCCCCC([O-])=O.CCCCCCCCCCCC([O-])=O BJZBHTNKDCBDNQ-UHFFFAOYSA-L 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- AXLHVTKGDPVANO-UHFFFAOYSA-N methyl 2-amino-3-[(2-methylpropan-2-yl)oxycarbonylamino]propanoate Chemical compound COC(=O)C(N)CNC(=O)OC(C)(C)C AXLHVTKGDPVANO-UHFFFAOYSA-N 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003607 modifier Substances 0.000 description 1
- BDRTVPCFKSUHCJ-UHFFFAOYSA-N molecular hydrogen;potassium Chemical compound [K].[H][H] BDRTVPCFKSUHCJ-UHFFFAOYSA-N 0.000 description 1
- 235000019691 monocalcium phosphate Nutrition 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 1
- 235000005985 organic acids Nutrition 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000010094 polymer processing Methods 0.000 description 1
- ODGAOXROABLFNM-UHFFFAOYSA-N polynoxylin Chemical compound O=C.NC(N)=O ODGAOXROABLFNM-UHFFFAOYSA-N 0.000 description 1
- JMTCDHVHZSGGJA-UHFFFAOYSA-M potassium hydrogenoxalate Chemical compound [K+].OC(=O)C([O-])=O JMTCDHVHZSGGJA-UHFFFAOYSA-M 0.000 description 1
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 description 1
- 229910052939 potassium sulfate Inorganic materials 0.000 description 1
- 235000011151 potassium sulphates Nutrition 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 239000012047 saturated solution Substances 0.000 description 1
- 150000004760 silicates Chemical class 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000001488 sodium phosphate Substances 0.000 description 1
- 229910000162 sodium phosphate Inorganic materials 0.000 description 1
- 159000000000 sodium salts Chemical class 0.000 description 1
- UJRAXLUXHBUNDO-UHFFFAOYSA-M sodium;hydron;oxalate Chemical compound [Na+].OC(=O)C([O-])=O UJRAXLUXHBUNDO-UHFFFAOYSA-M 0.000 description 1
- 235000014347 soups Nutrition 0.000 description 1
- 239000012798 spherical particle Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 238000005728 strengthening Methods 0.000 description 1
- 229910052567 struvite Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 239000002426 superphosphate Substances 0.000 description 1
- 238000013268 sustained release Methods 0.000 description 1
- 239000012730 sustained-release form Substances 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
- 229910000391 tricalcium phosphate Inorganic materials 0.000 description 1
- TWQULNDIKKJZPH-UHFFFAOYSA-K trilithium;phosphate Chemical compound [Li+].[Li+].[Li+].[O-]P([O-])([O-])=O TWQULNDIKKJZPH-UHFFFAOYSA-K 0.000 description 1
- RYFMWSXOAZQYPI-UHFFFAOYSA-K trisodium phosphate Chemical compound [Na+].[Na+].[Na+].[O-]P([O-])([O-])=O RYFMWSXOAZQYPI-UHFFFAOYSA-K 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- LRXTYHSAJDENHV-UHFFFAOYSA-H zinc phosphate Chemical compound [Zn+2].[Zn+2].[Zn+2].[O-]P([O-])([O-])=O.[O-]P([O-])([O-])=O LRXTYHSAJDENHV-UHFFFAOYSA-H 0.000 description 1
- 229910000165 zinc phosphate Inorganic materials 0.000 description 1
- LPEBYPDZMWMCLZ-CVBJKYQLSA-L zinc;(z)-octadec-9-enoate Chemical compound [Zn+2].CCCCCCCC\C=C/CCCCCCCC([O-])=O.CCCCCCCC\C=C/CCCCCCCC([O-])=O LPEBYPDZMWMCLZ-CVBJKYQLSA-L 0.000 description 1
- ZPEJZWGMHAKWNL-UHFFFAOYSA-L zinc;oxalate Chemical compound [Zn+2].[O-]C(=O)C([O-])=O ZPEJZWGMHAKWNL-UHFFFAOYSA-L 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J2/00—Processes or devices for granulating materials, e.g. fertilisers in general; Rendering particulate materials free flowing in general, e.g. making them hydrophobic
- B01J2/006—Coating of the granules without description of the process or the device by which the granules are obtained
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05G—MIXTURES OF FERTILISERS COVERED INDIVIDUALLY BY DIFFERENT SUBCLASSES OF CLASS C05; MIXTURES OF ONE OR MORE FERTILISERS WITH MATERIALS NOT HAVING A SPECIFIC FERTILISING ACTIVITY, e.g. PESTICIDES, SOIL-CONDITIONERS, WETTING AGENTS; FERTILISERS CHARACTERISED BY THEIR FORM
- C05G5/00—Fertilisers characterised by their form
- C05G5/30—Layered or coated, e.g. dust-preventing coatings
Definitions
- the present invention relates to water soluble inorganic salts having substantially water insoluble coatings and to processes for the preparation thereof. More particularly the present invention relates to the water soluble fertilizers provided with substantially water insoluble coatings for slow/sustained release thereof.
- Water soluble salts are of extensive use in aqueous solutions. Especially salts selected from the group consisting of halides, nitrates, phosphates and sulfates are of extensive use in the fertilizer industry. Such salts often contain cations of Li, Na, Mg and Ca and preferably contain cations which also serve as nutrients and micronutrients e.g., K, NH., Fe, Mn, Cu, Co, Mo and Zn. In certain cases, however, slow release of the salt into the aqueous solution is required. An important example is slow release fertilizers. Use of slow release fertilizers instead of direct application of the fertilizer as a soluble salt provides many advantages such as: increased efficiency, reduced number of applications, reduced soil toxicity, reduced nutrient losses and thereby lower contamination of underground water.
- SUBSTITUTESHEET Tne first aoproacn involves the preparation of low solubility compounds sucn as: urea formaldehyde (Hasegawa and Onishi, JP63, 134,593, Stajer, Glaser, Vidensky and Vosolsobe (CS 2588147), syngemte (Von Maessennausen, Czikkely and Jung, DE 3,518,369) ana magnesium ammonium phosonate (JP 82 67,089); or water soluble salts granulated, pressed or sintered with other compounds such as gypsum (Koike JP 61,295,294), coal (Fujimori BR 88 03,282), coal ash (Oshikata, JP 60,239,381) and silicates (JP 59 04,397).
- the main disadvantage of low-solubility compounds or formulations is the high cost of raw materials and/or manufacturing.
- Coatings of soluble salts comprise polymers (Hansen, L'S 3,223,518, Showa, JP 60,103,093; U.S. 3,223,518), sulfur, wax ( ⁇ ibner, DE 3,321,053), pitch (Zou, CM 1,030,745), soybean formulation (NL 34 03,505), salts of fatty acids (Pipko, Manor and Ziv, EP 276,179), sodium silicate (Ko ⁇ ssarov and Panfileva SU 1,353,767), iron phospnate (Eibner DE 3,321,053), magnesium ammonium phosphate (Ninon JP 81,164,090) and gypsum or cement (JP 59,50,086).
- SUBSTITUTESHEET With this state of the art in mind, it is an object c: the present invention to provide a process for modifying a particulate solid comprising a water soluble inorganic salt, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates, so as to decrease the rate of dissolution of such salts in water.
- the surface of the water soluble, inorganic salt particles can be converted through reaction with suitable reagents into a water insoluble coating thereby decreasing the dissolution of the water soluble salt. It was surprisingly found that such coating can be formed even when the reagent is applied in aqueous solution.
- the present invention provides a process for modifying a particulate solid comprising a water soluble inorganic salt, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates, so as to decrease the rate of dissolution of said salt in aqueous solution, said process comprising contacting said salt with at least one reagent which reacts with one or more ions of
- SUBSTITUTESHEET said salt to form a reaction product which coats said salt, said reaction product containing at least one ion of said water soluble inorganic salt as a component thereof and having a water solubility not more than half that of the original uncoated organic salt.
- particulate solids as used herein concerns particulate solids that range from soluble salts only to compositions that contain at least one water soluble salt as one constituent amongst others that may be water soluble or water insoluble.
- particulate table salt consisting of 100% sodium chloride is included in the present invention as is a particulate dry soup containing about 10% sodium chloride.
- particulate solid for the purposes of the present invention, several fertilizer materials are listed below. These were chosen since controlling the rate of dissolution of particulate fertilizer is a major, though by no means exclusive, object of this invention.
- a) muriate of potash which is over 95% KC1 and the remainder of which is mainly NaCl, both of which are fully water soluble: b) granulated "triple super phosphate" which is made fr om phosphate rock and wet process acid and contains soluble monocalci urn phospnate as the main constituent and may contain some 20% of insoluble solids originating in the rock (silica, iron oxide%) and in clay used as a binder for the granulation process; c) granulated NPK made of ammonium phosphate, muriate of potash arid phosphate rock, which may contain over 50% of the water insoluble rock.
- the water soluble salts present in the particulate solids to which this invention refers are halides, sul ⁇ fates, nitrates and phosphates. Naturally, when anions of these salts report to an aqueous solution an equivalent amount of cations do so.
- said reagent can react with either said anion or its companion cation.
- a process for modifying a particulate solid comprising a water soluble inorganic salt, so as to decrease the rate of dissolution of said salt in aqueous solution, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates and optionally including cations of K, MH ⁇ , re, Mn, Cu, Co, Mo and Zn, said process comprising contacting said salt with at least
- SUBSTITUTESHEET one reagent whic. reacts with one or more ions of said salt to form a reaction product which coats said salt, sai ⁇ reaction product containing at least one of said ions as a component thereof and having a water solubility not more tnan half that of the original uncoated organic salt.
- a process for modifying a particulate solid comprising a water soluble inorganic salt, said process comprising contacting particles of said particulate solid with at least one reagent which reacts with one or more ions of said salt to form a reaction product which coats said particles.
- the invention also provides a particulate solid comprising a water soluble inorganic salt, said salt being selected from the group consisting of halioes, nitrates, phosphates ana sulfates, and sai ⁇ salt having a substantially water insoluble coating, said coating having been formed by contacting said salt with at least one reagent which reacts with one or more ions of said water soluble salt to form a reaction product which coats said salt, said reaction product containing at least one ion of said water soluble organic salt as a component thereof and having a water solubility not more than half that of the original uncoated organic salt.
- a water soluble inorganic salt said salt being selected from the group consisting of halioes, nitrates, phosphates ana sulfates, and sai ⁇ salt having a substantially water insoluble coating, said coating having been formed by contacting said salt with at least one reagent which reacts with one or more ions of said water
- the invention provides a particulate solid comprising a water soluole inorganic salt, sai ⁇ salt
- SUBSTITUTESHEET being selected from the group consisting of halides, nitrates, phosphates and sulfates, and optionally including cations of K, NH., Fe, Mn, Cu, Co, Mo and Zn, said salt having a substantially water insoluble coating, said coating having been formed by contacting said salt with at least one reagent which reacts with one or more of said ions to form a reaction product which coats said salt, said reaction product containing at least one of said ions as a component thereof and having a water solubility not more than half that of the original uncoated organic salt.
- the invention also provides a particulate solid according to the present invention comprising a water soluble inorganic salt wherein particles of said particulate solid are provided with a substantially water insoluble coating, said coating on said particles having been formed by contacting said salt with at least one reagent which reacts with one or more of said ions to form a reaction product which coats said particles, said reaction product containing at least one of said ions as a component thereof and having a water solubility not more than half that of the original uncoated organic salt.
- said reaction product has a water solubility less than 10% of that of the original uncoated water soluble inorganic salt.
- the reagent is applied in a combination with at least one of the group comprising surfactants, viscosity, modifiers, water-repellants and binders, to improve mechanical strength, adhesivity to the particle and to further reduce solubility in water.
- SUBSTITUTESHEET One example is treatment by a surface active agent (which is arice to the reagent or applied at a subsequent stage).
- a surface active agent which is arice to the reagent or applied at a subsequent stage.
- Such agent might be selected, for example, from those used for anticaking of crystals or for flotation (e.g. amines).
- the polar side of the surface active agent (surfactant) interacts with the reaction product in the particulate cover, while the hydrophobic end decreases interaction with water and thereby affects solubility.
- This hydrophobic end also provides for further coating of the particle by hydrophobic solvents as hydrocarbons.
- Other treatments may include thermal treatment for affecting the coating's characteristics (e.g., converting gypsum dihydrate to hemi-hydrate), a second treatment by the same reagent or treatment by a second reagent (e.g., treatment by a base to convert CaHPO, in the coating to the less soluble Ca,(P0.) ? ), etc.
- tne aDove method suffers from tne disadvantages that it requires the introduction ana use cf bctn an organic acid or salt and a metal oxide or caroonate to interreact with each otner to form a coating around the fertilizer particles as opposed to tne present invention in which water soluble fertilizer particles tnemselves actively interact with the reagent and ions of said water soluble fertilizer form an integral component of the formed water insoluble coating.
- tne present invention assures that the reaction to form the water insoluble coating takes place on the surface of the water soluble salt, since in the present invention this salt functions as one of the reactants, which is not the case with said prior art process. This further assures that loss of reagent due to precipi ⁇ tation away from the surface of the salt does not take place.
- the fertilizer to be coated according to the present invention may be selected from the well known water scluole fertilizers such as: potassium nitrate, ootassiu- sulfate, ammonium nitrate. monopotassium pnosohate, ammonium ohosonates, mixtures of N. P.K. fertilizers, etc.
- water scluole fertilizers such as: potassium nitrate, ootassiu- sulfate, ammonium nitrate. monopotassium pnosohate, ammonium ohosonates, mixtures of N. P.K. fertilizers, etc.
- SUBSTITUTESHEET The main nutrients providec tnrougn fertilizers are N, ? ano K.
- Micro-nutrients consist of Fe, Mn, Cu, Co, Mo, In, etc. N is provi ⁇ ed as ammonium salts (e.g., (NH birthdayS0 ⁇ ), NO.*,- salts (e.g., Ca(N0-.) 2 , NaNC,) and urea. is provided in its soluble salts such as KC1 ana KoSO. and P as pnosonates.
- ammonium salts e.g., (NH birthdayS0 ⁇ )
- NO.* - salts
- urea is provided in its soluble salts such as KC1 ana KoSO. and P as pnosonates.
- fertilizers m whicn both the amon and the cations comprise a nutrient, e.g. KNO, ( H 4 ) 2 HP
- Reagents forming water insoluble salts with the anion or the cation of the water soluble salts are suitable for tne process.
- the surface cf tne particle is converted according to the reaction: K-.SO4 ⁇ * rUSiF, > K 2 SiF 6 + H 2 S0 4 .
- the modified particle thus comprises K ⁇ SO. coated with K ⁇ S F ⁇ - with substantially no decrease of nutrient content.
- nutrient replacement is low and the replaced nutrient can oe recovered as in the reaction: 2 S0 4 + Ca(N0 3 ) 2 > CaS0 4 ⁇ « ⁇ KN0 3 .
- the reagent can be chosen to also add micro-nutrients to tne fertilizer.
- micro-nutrients e.g, ZnCHN. ⁇ SO. ) 2 or cobalt ammonium nitrate are suitable insoluble coatings of ammonium salts.
- preferred embodiments of the present invention will include the nutrients N, P or K as a component of the reaction product and especially preferred embodiments of the present invention will also incorporate one or more micronutrients selected from Fe, Mn, Cu, Co, Mo and Zn in said coating.
- Reagents for the process are those forming water insoluble salts with at least one of the ions comprising the fertilizer.
- K salts can be coated with K 2 Ca(S0 4 ) 2 , K 3 Co(N0 2 )g and K 2 SlF g ;
- NH 4 + salts form insoluble coatings such as H 4 CaP0 4 , NH 4 CoP0 4 - H 4 gP0 4 and H 4 MnP0 4 ;
- soluble calcium phosphates or Ca(NC ) can be coated with insoluble salts such as CaCO ⁇ , CaF-, Ca laurate, Ca oxalate, Ca 3 (P0 4 ) 2 and Ca tartarate;
- water soluble phosphate can be coated with water insoluble phosphates such as FeP0 4 and water soluble sulfates with water
- reagents may be applied in vapor phase (NH 3 , SiF ⁇ ), in non-aqueous liquid, as a dispersion, emulsion or even in aqueous solution.
- the reagent may also be sprayed over the solid particles.
- the rate of release of the water soluble salt is dependent on coating thickness, which can be affected by parameters of reagent application.
- the rate of release is also affected by solubility of the coating wherein less soluble coatings provides for slower release.
- Particles coated in the process of this invention can be further coated by other coating materials such as wax.
- SUBSTITUTESHEET Modified particulate solids obtained according to the invention having a low rate of dissolution in aqueous solutions, provide excellent starting material for additional treatments for further improvement of their properties, i.e., improvement of mechanical strength, further reduction of rate of dissolution, etc.
- Such additional treatment may, for example, use components such as surfactants, binders and polymeric materials dissolved or dispersed in aqueous solution.
- Such option is, in fact, impractical with unmodified water-soluble particulate solids, as it would lead to the dissolution of a major part of the unmodified particulate.
- the reaction product of low water solubility that coats the soluble salt in the modified particulate solid may, in some cases, perform as a low-cost filler in other coatings formed cocurrently with, or subsequently to, it.
- the coating is formed on reaction with the soluble salt particle and includes at least one of its ions, good adhesion to the particle is ootained avoiding the need of binders and improving the ability to affect the coating of less spherical particles.
- Formation of inorganic coating reduces the ⁇ anger of flammability ana of formation of explosive materials.
- SUBSTITUTE SHEET The process of the invention allows using reagents in vapor phase, in non-aqueous liquid, as an emulsion or even in aqueous solution. Melting of reagents is not required. In addition reaction of the reagent with the water soluble particle is spontaneous requiring no energy introduction. The process thus does not require energy input or temperature elevation. In fact in most cases low temperature is favorable, which is advantageous for coating of temperature-sensitive compounds such as HN.N0-,.
- the reagent is introduced in an organic solvent.
- organic solvents such as those defined in Israel
- Patent 57024 corresponding to U.S. Patent No. 4,291,007, the teachings of which are incorporated herein by reference, bind H-,SiF, to form the fluosilicate of the amine according to the reaction
- R NH- + H-,SiF, > R NH. HSiF, or (R NH. 7 SiF,. n J-n n 4-n 6 n 4-n . o wherein n 1 , 2 or 3.
- Reaction may be affected and controlled by the properties of the solvent, e.g., it is known that amines prefer nitric acid over
- the solvent may be use ⁇ to extract a reagent from its a ⁇ ueous solution thereny permitting the use of reagents formed as by-products even if in dilute solutions (e.g., H-,SiFg formed on scrubbing Sir, , in phosphoric acid industry); and
- the solvent may be chosen so as to form tne required organic coating on the top of the insoluble salt which is formed.
- the process of the invention provides for higher compatibility with fertilizer production and utilization.
- SUBSTITUTESHEET examples wnich include preferred embodiments will serve to illustrate the practice of tms invention, it being understood that tne particulars shown are by way of example and for purposes of illustrative discussicn of preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of formulation procedures as well as of the principles and conceptual aspects of the invention.
- Potassium nitrate granules with sizes ranging between about 1 mm and 5 mm were introduced into water in w/w ratio of 1:20 respectively. Strong shaking was applied in a mechanical shaker at ambient temperature. Complete dissolution was observed after about 3 minutes. (No insoluble matter was left in the solution).
- Potassium nitrate granules from the batch used in Comparative Example A were introduced into 36% w/w a ⁇ ueous solution of fluosilicic acid and gently stirred in a mechanical shaker at ambient temperature for a period of about five hours to effect the coating thereof. No indication of potassium nitrate dissolution was found and it is assumed that any potassium nitrate exiting from the coated granules was immediately reacted with the fluosilicic acid still in solution and adds to the coating. Independent precipitation of I SiFg was not
- the treated granules were separated from tne solution, washe ⁇ and introduced into water in w/w ratio of 1:20 respectively. Strong shaking was applied in a mechanical shaker at ambient temperature. Potassium nitrate dissolution could be visually followed as the coating formed is partially transparent. About eight hours were required for substantial dissolution of the potassium fluosilicate coated potassium nitrate. After 16 hours only the coating remains in solution.
- This example shows that coating potassium nitrate with potassium fluosilicate slows its dissolution by a factor of 2 orders of magnitude.
- Magnesium phosphate Magnesium fluoride 0.008 Magnesium laurate 0.007 Magnesium oleate 0.024 Magnesium oxalate 0.07
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Abstract
The invention provides a process for modifying a particulate solid comprising a water soluble inorganic salt, the salt being selected from the group consisting of halides, nitrates, phosphates and sulfates, so as to decrease the rate of dissolution of the salt in aqueous solution, the process comprising contacting the salt with at least reagent which reacts with one or more ions of the salt to form a reaction product which coats the salt, the reaction product containing at least one ion of the water soluble inorganic salt as a component thereof and having a water solubility not more than half that of the original uncoated water soluble inorganic salt.
Description
A PROCESS FOR MODIFYI NG PARTI CULATE SOLI DS AND PARTI CULATE SOLIDS PREPARED
THEREBY
The present invention relates to water soluble inorganic salts having substantially water insoluble coatings and to processes for the preparation thereof. More particularly the present invention relates to the water soluble fertilizers provided with substantially water insoluble coatings for slow/sustained release thereof.
Water soluble salts are of extensive use in aqueous solutions. Especially salts selected from the group consisting of halides, nitrates, phosphates and sulfates are of extensive use in the fertilizer industry. Such salts often contain cations of Li, Na, Mg and Ca and preferably contain cations which also serve as nutrients and micronutrients e.g., K, NH., Fe, Mn, Cu, Co, Mo and Zn. In certain cases, however, slow release of the salt into the aqueous solution is required. An important example is slow release fertilizers. Use of slow release fertilizers instead of direct application of the fertilizer as a soluble salt provides many advantages such as: increased efficiency, reduced number of applications, reduced soil toxicity, reduced nutrient losses and thereby lower contamination of underground water.
In the prior art literature there are described two basic approaches for the preparation of slow release salts, i.e., the preparation of. low solubility formulations or the coating of a water soluble salt.
SUBSTITUTESHEET
Tne first aoproacn involves the preparation of low solubility compounds sucn as: urea formaldehyde (Hasegawa and Onishi, JP63, 134,593, Stajer, Glaser, Vidensky and Vosolsobe (CS 2588147), syngemte (Von Maessennausen, Czikkely and Jung, DE 3,518,369) ana magnesium ammonium phosonate (JP 82 67,089); or water soluble salts granulated, pressed or sintered with other compounds such as gypsum (Koike JP 61,295,294), coal (Fujimori BR 88 03,282), coal ash (Oshikata, JP 60,239,381) and silicates (JP 59 04,397). The main disadvantage of low-solubility compounds or formulations is the high cost of raw materials and/or manufacturing.
Coatings of soluble salts comprise polymers (Hansen, L'S 3,223,518, Showa, JP 60,103,093; U.S. 3,223,518), sulfur, wax (Ξibner, DE 3,321,053), pitch (Zou, CM 1,030,745), soybean formulation (NL 34 03,505), salts of fatty acids (Pipko, Manor and Ziv, EP 276,179), sodium silicate (Koππssarov and Panfileva SU 1,353,767), iron phospnate (Eibner DE 3,321,053), magnesium ammonium phosphate (Ninon JP 81,164,090) and gypsum or cement (JP 59,50,086).
Current coating material and processes involve many disadvantages such as low resistance to moisture penetration, explosivity with certain fertilizers, high cost raw materials, introducing into the soil of non-degradable materials and difficulties in achievement of well adhering complete coatings. The main disadvantages, however, relate to complicated and expensive coating processes, to reduction of
SUBSTITUTESHEET
nutrient content, to addition of oalast and to reαuceα freedom in tailoring fertilizer compositions.
As is known, even tne preferred prior art processes of coating witn a polymer are complex, multistage operations which involve elements from polymer processing such as the use of a solvent .vnich may cause safety ana environmental difficulties and which has to be evaoorateα and recovered, curing, cross-linking and condensation. These operations are expensive, require know-how ana equipment wnicn is strange to the fertilizer industry and in some cases, incompatible with the fertilizer due, e.g., to relatively high temperatures or to formation of explosive compositions with K!\LN0, containing fertilizers. Current processes of coating witn inorganic materials are also tedious, require several stages and may require binders. Thus, coating with MgNH.PO. comprises spraying of H,P0- solution followed by dusting with MgO ana SiO-, and tnen spraying NH.OH solution or ammomation with gaseous ammonia.
With current coating materials ana processes, consiaerable amounts of coating are required (up to 50" of fertilizer's weight). Nutrient content thus decreases and expensive raw-materials are consumed, balast such as polymers, sodium silicate and calcium stearate, making uo a substantial component of tne coateα materials. Cost cf raw matc- a s ana of coating processes, toxicity ana coating builcup in the soil thus limit tne use of coateα fertilizers.
SUBSTITUTESHEET
With this state of the art in mind, it is an object c: the present invention to provide a process for modifying a particulate solid comprising a water soluble inorganic salt, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates, so as to decrease the rate of dissolution of such salts in water.
It is another object of the present invention to provide a new and simpler method of coating which is compatible with the fertilizer industry, enables the utilization of low-cost raw materials, decreases the reduction in nutrient content and addition of balast and enables the preparation of tailor made fertilizers.
In accordance with the present invention it has now been found that the surface of the water soluble, inorganic salt particles can be converted through reaction with suitable reagents into a water insoluble coating thereby decreasing the dissolution of the water soluble salt. It was surprisingly found that such coating can be formed even when the reagent is applied in aqueous solution.
Thus, the present invention provides a process for modifying a particulate solid comprising a water soluble inorganic salt, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates, so as to decrease the rate of dissolution of said salt in aqueous solution, said process comprising contacting said salt with at least one reagent which reacts with one or more ions of
SUBSTITUTESHEET
said salt to form a reaction product which coats said salt, said reaction product containing at least one ion of said water soluble inorganic salt as a component thereof and having a water solubility not more than half that of the original uncoated organic salt.
The term particulate solids as used herein concerns particulate solids that range from soluble salts only to compositions that contain at least one water soluble salt as one constituent amongst others that may be water soluble or water insoluble. Thus, particulate table salt consisting of 100% sodium chloride is included in the present invention as is a particulate dry soup containing about 10% sodium chloride. For further clarification of the term "particulate solid" for the purposes of the present invention, several fertilizer materials are listed below. These were chosen since controlling the rate of dissolution of particulate fertilizer is a major, though by no means exclusive, object of this invention. In this connection it is appropriate to mention that the term "rate of dissolution" is commonly used loosely with respect to the interaction of particulate commercial materials with aqueous solutions; the implication being that as the truly water soluble constituents dissolve, the particle disintegrates. This clearly applies to particulate fertilizer that frequently contains insoluble constitutents.
Thus examples of particulate solids which can be modified according to the above process include:
SUBSTITUTESHEET
β
a) muriate of potash, which is over 95% KC1 and the remainder of which is mainly NaCl, both of which are fully water soluble: b) granulated "triple super phosphate" which is made fr om phosphate rock and wet process acid and contains soluble monocalci urn phospnate as the main constituent and may contain some 20% of insoluble solids originating in the rock (silica, iron oxide...) and in clay used as a binder for the granulation process; c) granulated NPK made of ammonium phosphate, muriate of potash arid phosphate rock, which may contain over 50% of the water insoluble rock.
As stated hereinbefore, the water soluble salts present in the particulate solids to which this invention refers are halides, sul¬ fates, nitrates and phosphates. Naturally, when anions of these salts report to an aqueous solution an equivalent amount of cations do so.
As explained hereinafter said reagent can react with either said anion or its companion cation.
In a preferred embodiment of the present invention there is provided a process for modifying a particulate solid comprising a water soluble inorganic salt, so as to decrease the rate of dissolution of said salt in aqueous solution, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates and optionally including cations of K, MHΛ, re, Mn, Cu, Co, Mo and Zn, said process comprising contacting said salt with at least
SUBSTITUTESHEET
one reagent whic. reacts with one or more ions of said salt to form a reaction product which coats said salt, saiα reaction product containing at least one of said ions as a component thereof and having a water solubility not more tnan half that of the original uncoated organic salt.
In an especially preferrec emoodiment of the present invention there is provided a process for modifying a particulate solid comprising a water soluble inorganic salt, said process comprising contacting particles of said particulate solid with at least one reagent which reacts with one or more ions of said salt to form a reaction product which coats said particles.
The invention also provides a particulate solid comprising a water soluble inorganic salt, said salt being selected from the group consisting of halioes, nitrates, phosphates ana sulfates, and saiα salt having a substantially water insoluble coating, said coating having been formed by contacting said salt with at least one reagent which reacts with one or more ions of said water soluble salt to form a reaction product which coats said salt, said reaction product containing at least one ion of said water soluble organic salt as a component thereof and having a water solubility not more than half that of the original uncoated organic salt.
In especially preferred embodiments the invention provides a particulate solid comprising a water soluole inorganic salt, saiα salt
SUBSTITUTESHEET
being selected from the group consisting of halides, nitrates, phosphates and sulfates, and optionally including cations of K, NH., Fe, Mn, Cu, Co, Mo and Zn, said salt having a substantially water insoluble coating, said coating having been formed by contacting said salt with at least one reagent which reacts with one or more of said ions to form a reaction product which coats said salt, said reaction product containing at least one of said ions as a component thereof and having a water solubility not more than half that of the original uncoated organic salt.
The invention also provides a particulate solid according to the present invention comprising a water soluble inorganic salt wherein particles of said particulate solid are provided with a substantially water insoluble coating, said coating on said particles having been formed by contacting said salt with at least one reagent which reacts with one or more of said ions to form a reaction product which coats said particles, said reaction product containing at least one of said ions as a component thereof and having a water solubility not more than half that of the original uncoated organic salt.
In an especially preferred embodiment of the present invention said reaction product has a water solubility less than 10% of that of the original uncoated water soluble inorganic salt.
SUBSTITUTESHEET
In a preferred embodiment, the reagent is applied in a combination with at least one of the group comprising surfactants, viscosity, modifiers, water-repellants and binders, to improve mechanical strength, adhesivity to the particle and to further reduce solubility in water.
In another preferred embodiment, additional operations are effected for further improvement of the solid particulate properties.
SUBSTITUTESHEET
One example is treatment by a surface active agent (which is arice to the reagent or applied at a subsequent stage). Such agent might be selected, for example, from those used for anticaking of crystals or for flotation (e.g. amines). The polar side of the surface active agent (surfactant) interacts with the reaction product in the particulate cover, while the hydrophobic end decreases interaction with water and thereby affects solubility. This hydrophobic end also provides for further coating of the particle by hydrophobic solvents as hydrocarbons.
Other treatments may include thermal treatment for affecting the coating's characteristics (e.g., converting gypsum dihydrate to hemi-hydrate), a second treatment by the same reagent or treatment by a second reagent (e.g., treatment by a base to convert CaHPO, in the coating to the less soluble Ca,(P0.)?), etc.
In EPA publication No. 276179 there is described and claimed a method for the manufacture cf physically prepared slow-release fertilizers, wherein the fertilizer particles are coated by at least one layer of a substantially water insoluble metal salt of an organic acid containing from 6 to 30 cabon atoms, particularly between 12 and 20 carbon atoms, or of water insoluble metal salts of a mixture of two or more such organic acids,, the metal salt(s) coating being formed in-sit' from the organic salt(s) and metal oxide or carbonate.
SUBSTITUTESHEET
As will be realized, nowever, tne aDove method suffers from tne disadvantages that it requires the introduction ana use cf bctn an organic acid or salt and a metal oxide or caroonate to interreact with each otner to form a coating around the fertilizer particles as opposed to tne present invention in which water soluble fertilizer particles tnemselves actively interact with the reagent and ions of said water soluble fertilizer form an integral component of the formed water insoluble coating.
Furthermore, tne present invention assures that the reaction to form the water insoluble coating takes place on the surface of the water soluble salt, since in the present invention this salt functions as one of the reactants, which is not the case with said prior art process. This further assures that loss of reagent due to precipi¬ tation away from the surface of the salt does not take place.
Although the process cf the present invention can be applied to all kincs cf ater soluble salts, tne following description concentrates on the treatment of water soluble fertilizers in orαer to modify these into fertilizers with slow release properties.
Thus, as in said European application the fertilizer to be coated according to the present invention, may be selected from the well known water scluole fertilizers such as: potassium nitrate, ootassiu- sulfate, ammonium nitrate. monopotassium pnosohate, ammonium ohosonates, mixtures of N. P.K. fertilizers, etc.
SUBSTITUTESHEET
The main nutrients providec tnrougn fertilizers are N, ? ano K. Micro-nutrients consist of Fe, Mn, Cu, Co, Mo, In, etc. N is proviαed as ammonium salts (e.g., (NH „S0Λ), NO.*,- salts (e.g., Ca(N0-.)2, NaNC,) and urea. is provided in its soluble salts such as KC1 ana KoSO. and P as pnosonates. Of higher value are fertilizers m whicn both the amon and the cations comprise a nutrient, e.g. KNO, ( H4)2HP04, H2P0 and NH_, 03.
Reagents forming water insoluble salts with the anion or the cation of the water soluble salts are suitable for tne process. Thus, e.g., on reacting O . particles witn rLSiFg, the surface cf tne particle is converted according to the reaction: K-.SO4 ÷* rUSiF, > K2SiF6 + H2S04.
The modified particle thus comprises K^SO. coated with K^S F^- with substantially no decrease of nutrient content. However, even on reaction with the otner ion, nutrient replacement is low and the replaced nutrient can oe recovered as in the reaction: 2S04 + Ca(N03)2 > CaS04 ■«■ KN03.
In another preferred embodiment the reagent can be chosen to also add micro-nutrients to tne fertilizer. Thus, e.g, ZnCHN.^ζSO. )2 or cobalt ammonium nitrate are suitable insoluble coatings of ammonium salts.
SUBSTITUTESHEET
Thus, preferred embodiments of the present invention will include the nutrients N, P or K as a component of the reaction product and especially preferred embodiments of the present invention will also incorporate one or more micronutrients selected from Fe, Mn, Cu, Co, Mo and Zn in said coating.
Reagents for the process are those forming water insoluble salts with at least one of the ions comprising the fertilizer. A person versed in the art can choose reagents according to solubility data and according to crystalographic know-how. According to the present invention, it will now be realized that, e.g., K salts can be coated with K2Ca(S04)2, K3Co(N02)g and K2SlFg; NH4 + salts form insoluble coatings such as H4CaP04, NH4CoP04- H4 gP04 and H4MnP04; soluble calcium phosphates or Ca(NC ) can be coated with insoluble salts such as CaCO^, CaF-, Ca laurate, Ca oxalate, Ca3(P04)2 and Ca tartarate; water soluble phosphate can be coated with water insoluble phosphates such as FeP04 and water soluble sulfates with water- msoluble sulfates such as CaS04 and BaS04.
In carrying out the process of the present invention, reagents may be applied in vapor phase (NH3, SiFα), in non-aqueous liquid, as a dispersion, emulsion or even in aqueous solution. The reagent may also be sprayed over the solid particles.
It has thus been found that on introducing particles comprising a water-soluble salt into gently mixed, relatively concentrated solution
SUBSTITUTESHEET
of the reagent at about ambient temperature, a water insoluble coating is immediately formed on the surface of the salt particles which prevents considerable losses of the soluble salt through dissolution in the aqueous solution.
The rate of release of the water soluble salt is dependent on coating thickness, which can be affected by parameters of reagent application. Thus in using the reagent in an aqueous solution, concentration of the aqueous solution, contact time and temperature. pH, reagent nature and additives to the solution, affect coating thickness and thereby the rate of release of the soluble salt.
The rate of release is also affected by solubility of the coating wherein less soluble coatings provides for slower release.
Unlike in other processes of coating water soluble particles, elevated temperatures are not required. The process is thus suitable for coating particles of unstable compounds such as HN4N0-,.
Particles coated in the process of this invention can be further coated by other coating materials such as wax.
SUBSTITUTESHEET
Modified particulate solids obtained according to the invention, having a low rate of dissolution in aqueous solutions, provide excellent starting material for additional treatments for further improvement of their properties, i.e., improvement of mechanical strength, further reduction of rate of dissolution, etc. Such additional treatment may, for example, use components such as surfactants, binders and polymeric materials dissolved or dispersed in aqueous solution. Such option is, in fact, impractical with unmodified water-soluble particulate solids, as it would lead to the dissolution of a major part of the unmodified particulate. The reaction product of low water solubility that coats the soluble salt in the modified particulate solid may, in some cases, perform as a low-cost filler in other coatings formed cocurrently with, or subsequently to, it.
The large variety of reagents suitable for modifying the solubility of water soluble particles according to the present invention allows freedom in choosing the reagents and adjusting them
SUBSTITUTESHEET
to reαuirements such as addition of micronutrients, adjustaoi 1ity to acid/base properties of the soil and low cost.
The latter point is of high importance as slow release fertilizers formed by current processes are relatively expensive due to high cost of raw material and of processing. Using the present invention thus allows the use of low cost reagents such as H-SiFg solutions. More specifically, it has now been found that introducing granules of KNO, into gently mixed
solution at ambient temperature results in their coating with water insoluble K7Si"g, wnich changes the solubility of the coated fertilizer. H-,SiFg is a very low cost reagent. In fact, in the neighborhood of wet process acid (WPA) production it may even have a negative value. Fluoride present in phosphate rock in the form of fluoroapatite results in fluosilicic acid in the phosphoric acid. On concentration of the WPA
SiF- evaporates and on scrubbing in water H2SiFg reforms according to the reaction:
2SiF. + H,0 > H„Slr- ÷ Si0 . A 2 c D 2
Since the coating is formed on reaction with the soluble salt particle and includes at least one of its ions, good adhesion to the particle is ootained avoiding the need of binders and improving the ability to affect the coating of less spherical particles.
Formation of inorganic coating reduces the αanger of flammability ana of formation of explosive materials.
SUBSTITUTE SHEET
The process of the invention allows using reagents in vapor phase, in non-aqueous liquid, as an emulsion or even in aqueous solution. Melting of reagents is not required. In addition reaction of the reagent with the water soluble particle is spontaneous requiring no energy introduction. The process thus does not require energy input or temperature elevation. In fact in most cases low temperature is favorable, which is advantageous for coating of temperature-sensitive compounds such as HN.N0-,.
In another preferred embodiment the reagent is introduced in an organic solvent. Thus, amine solvents such as those defined in Israel
Patent 57024 corresponding to U.S. Patent No. 4,291,007, the teachings of which are incorporated herein by reference, bind H-,SiF, to form the fluosilicate of the amine according to the reaction
R NH- + H-,SiF, > R NH. HSiF, or (R NH. 7SiF,. n J-n n 4-n 6 n 4-n . o wherein n = 1 , 2 or 3.
Reacting this organic phase with a solid particle containing KNO^ for example, results in a reaction of forming a water insoluble coating on the particle according to the reaction
(R NH. )_SiF, + 2KN0, > 2R.NH. NO, + 9SiF,. n 4-n'2 6 3 4 4-n 3 2 6
Introduction of the reagent in the presence of an organic solvent provides several advantages such as:
1. Reaction may be affected and controlled by the properties of the solvent, e.g., it is known that amines prefer nitric acid over
SUBSTITUTESHEET
fluosilicic acid thereby Droviding a driving force for tne reaction;
2. the solvent may be useα to extract a reagent from its aαueous solution thereny permitting the use of reagents formed as by-products even if in dilute solutions (e.g., H-,SiFg formed on scrubbing Sir,, in phosphoric acid industry); and
3. the solvent may be chosen so as to form tne required organic coating on the top of the insoluble salt which is formed.
The extensive know-how in the field of crystalization, and in benaviour of saturated and cf super-saturated solutions can be utilized for adjusting coating's properties. Small amounts of additives may affect the habit of coating and improve product properties.
As both fertilizers and soil are inorganic and as fertilizer release and utilization are dependent on water presence, the process of the invention provides for higher compatibility with fertilizer production and utilization.
While the invention will now be described in connection with certain preferred embodiments in the following examples so that aspects thereof may be more fully unαerstood and appreciated, it is not intended to limit the invention to these particular embodiments. On the contrary. it is intended to cover all alternatives, modifications and eαuivalents as may be included within the scooe of the invention as defined by the appended claims. Thus, the following
SUBSTITUTESHEET
examples wnich include preferred embodiments will serve to illustrate the practice of tms invention, it being understood that tne particulars shown are by way of example and for purposes of illustrative discussicn of preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of formulation procedures as well as of the principles and conceptual aspects of the invention.
Comparative Example A
Potassium nitrate granules with sizes ranging between about 1 mm and 5 mm were introduced into water in w/w ratio of 1:20 respectively. Strong shaking was applied in a mechanical shaker at ambient temperature. Complete dissolution was observed after about 3 minutes. (No insoluble matter was left in the solution).
Example 1
Potassium nitrate granules from the batch used in Comparative Example A were introduced into 36% w/w aαueous solution of fluosilicic acid and gently stirred in a mechanical shaker at ambient temperature for a period of about five hours to effect the coating thereof. No indication of potassium nitrate dissolution was found and it is assumed that any potassium nitrate exiting from the coated granules was immediately reacted with the fluosilicic acid still in solution and adds to the coating. Independent precipitation of I SiFg was not
SUBSTITUTESHEET
ooserveα thus strengthening tne assumption that K7SiFg was formeα solely as a coating on tne granules ana not independent thereof.
The treated granules were separated from tne solution, washeα and introduced into water in w/w ratio of 1:20 respectively. Strong shaking was applied in a mechanical shaker at ambient temperature. Potassium nitrate dissolution could be visually followed as the coating formed is partially transparent. About eight hours were required for substantial dissolution of the potassium fluosilicate coated potassium nitrate. After 16 hours only the coating remains in solution.
This example shows that coating potassium nitrate with potassium fluosilicate slows its dissolution by a factor of 2 orders of magnitude.
Having illustrated the principals of the present invention and the carrying out thereof in the above example it will now be simple for men skilled in tne art to carry out the present invention with other ions simply by consulting any handbook and noting the comparative solubility of soluble and substantially insoluble salts.
Thus, e.g., from The Handbook of Chemistry and Physics, Chemical Rubber Co. the following listing of solubilities of a gram of salts per 100 gram H-,0 in cold water can be founα, which listings are presented hereinafter for eacn ion, first with regard to water soluble
SUBSTITUTESHEET
salts and then with regard to less soluble salts which can serve as the reaction product coating for the first batch of water soluble salts.
In the following lists, "i" stands for insoluble.
SUBSTITUTE SHEET
Sodium salts Cold water
Sodium nitrate 92.1
Sodium hydrogen oxalate 1.7 Sodium phosphate 1.5 Sodium fluosilicate 0.65
Lithium salts
Lithium nitrate 90
Lithium laurate 0.15 Lithium phosphate 0.04 Lithium fluoride 0.27
Magnesium salts
Magnesium nitrate hexahydrate 125
Magnesium phosphate Magnesium fluoride 0.008 Magnesium laurate 0.007 Magnesium oleate 0.024 Magnesium oxalate 0.07
SUBSTITUTESHEET
K. salts
Potassium sulfate 12
Potassium chloride 34.7
Potassium nitrate 13.3
Potassium dihydrogen phosphate 33
Dipotassium hydrogen phosphate 167
Potassium hydrogen oxalate 2.5
Potassium hydrogen tartarate 0.37
Potassium fluosilicate 0.12 Potassium calcium sulfate
(syngenite) 0.25
Calcium salts
Calcium dihydrogen phosphate 1.8 Calcium nitrate 121
Calcium sulfate 0.2
Calcium carbonate 0.001
Calcium fluoride 0.002
Calcium laurate 0.004
Calcium oxalate 0.0007
Calcium phosphate 0.002
Calcium tartrate 0.03
SUBSTITUTESHEET
1370
24
Ammonium salts
Ammonium sulfate 70.6
Ammonium nitrate 118.3
Ammonium dihydrogen phosphate 22.7
Ammonium hydrogen phosphate 57.5
Ammonium calcium phosphate i
Ammonium magnesium phosphate 0.02
Ammonium cobalt phosphate i
Ammonium manganese phosphate 0.003
Ammonium zinc sulfate 7
Cobalt ammonium nitrate 1.7
Cobalt ammonium sulfate 1.4
Cobalt ammonium chloride 0.4
SUBSTITUTESHEET
Iron Salts
SUBSTITUTE SHEET
/01370
2
Cobalt Salts
Cobalt chloride 38
Cobalt nitrate 134
Cobalt citrate 0.8
Cobalt oxalate i
Cobalt phosphate i
Zinc Salts
Zinc chloride 432
Zinc nitrate 114
Zinc oleate i
Zinc oxalate 0.0008
Zinc phosphate i
Phosphates
Potassium dihydrogen phosphate 33 Ammonium dihydrogen phosphate 22.7
Iron (III) phosphate i
Cobalt (II) phosphate i
Copper (II) phosphate i
Zi c phosphate i
SUBSTITUTESHEET
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative examples and that the present invention may be embodied in other specific forms without departing from the essential attributes thereof, and it is therefore desired that the present embodiments and examples be considered in all respects as illustrative and not restrictive, reference being made to the appended claims, rather than to the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
SUBSTITUTESHEET
Claims
1. A process for modifying a particulate solid comprising a water soluble inorganic salt, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates, so as to decrease the rate of dissolution of said salt in aqueous solution, said process comprising contacting said salt with at least one reagent which reacts with one or more ions of said salt to form a reaction product which coats said salt, said reaction product containing at least one ion of said water soluble inorganic salt as a component thereof and having a water solubility not more than half that of the original uncoated water soluble inorganic salt.
2. A process for modifying a particulate solid comprising a water soluble inorganic salt, as claimed in claim 1, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates, and optionally including cations of K, NH4, Fe, Mn, Cu, Co, Mo and Zn, so as to decrease the rate of dissolution of said salt in aqueous solution, said process comprising contacting said salt with at least one reagent which reacts with one or more ions of said salt to form a reaction product which coats said salt, said reaction product containing at least one of said ions as a component thereof and having a water solubility not more than half that of the original uncoated water soluble inorganic salt.
3. A process according to claim 1 wherein said particulate solid is contacted with an aqueous medium containing said reagent.
4. A process according to claim 1 for modifying a particulate solid comprising a water soluble inorganic salt, said process comprising contacting particles of said particulate solid with at least one reagent which reacts with one or more ions of said salt to form a reaction product which coats said particles.
5. A particulate solid comprising a water soluble inorganic salt, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates, and said salt having a substantially water insoluble coating, said coating having been formed by contacting said salt with at least one reagent which reacts with one or more ions of said water soluble salt to form a reaction product which coats said water soluble salt, said reaction product containing at least one ion of said water soluble inorganic salt as a component thereof and having a water solubility not more than half that of the original uncoated water soluble inorganic salt.
6. A particulate solid as claimed in claim 5 comprising a water soluble inorganic salt, said salt being selected from the group consisting of halides, nitrates, phosphates and sulfates, and optionally containing cations of K, NH4, Fe, Mn, Cu, Co, Mn and Zn, said salt having a substantially water insoluble coating, said coating having been formed by contacting said salt with at least one reagent which reacts with one or more of said ions to form a reaction product which coats said salt, said reaction product containing at least one of said ions as a component thereof and having a water solubility not more than half that of the original uncoated water soluble inorganic salt.
7. A particulate solid according to claim 5 wherein said reaction product has a water solubility less than 10% of that of the original uncoated water soluble inorganic salt.
8. A particulate solid according to claim 5 wherein said reaction product is selected from K2Ca(SO4)2, K3Co(NO2)6 and K2SiF6.
9. A particulate solid according to claim 5 wherein said reaction product is selected from calcium sulfate, calcium carbonate, calcium fluoride, calcium laurate, calcium oxalate, calcium phosphate and calcium tartrate.
10. A particulate solid according to claim 5 wherein said reaction product includes nitrogen, phosphorus or potassium as a component thereof.
11. A particulate solid according to claim 5 wherein said reaction product further includes a micronutrient selected from Fe, Mn, Cu, Co, Mo and Zn as a component thereof.
12. A particulate solid according to claim 5 comprising a water soluble inorganic salt, wherein particles of said particulate solid are provided with a substantially water insoluble coating, said coating on said particles having been formed by contacting said salt with at least one reagent which reacts with one or more ions of said waster-soluble salt to form a reaction product which coats said particles, said reaction product containing at least one ion of said water-soluble inorganic salt as a component thereof and having a water solubility not more than half that of the original uncoated water-soluble inorganic salt.
13. A particulate solid according to claim 5, wherein said water-soluble inorganic salt is KNO3.
14. A particulate solid according to claim 13, wherein said reaction product is K2SiF6.
15. A particulate solid according to claim 1, further comprising a surfactant.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL10237092 | 1992-06-30 | ||
| IL10237092A IL102370A (en) | 1992-06-30 | 1992-06-30 | Process for modifying particulate solids and particulate solids prepared thereby |
| PCT/GB1993/001370 WO1994000405A1 (en) | 1992-06-30 | 1993-06-30 | A process for modifying particulate solids and particulate solids prepared thereby |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP0648198A1 true EP0648198A1 (en) | 1995-04-19 |
Family
ID=11063777
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP93914848A Ceased EP0648198A1 (en) | 1992-06-30 | 1993-06-30 | A process for modifying particulate solids and particulate solids prepared thereby |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0648198A1 (en) |
| AU (1) | AU4507193A (en) |
| IL (1) | IL102370A (en) |
| WO (1) | WO1994000405A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9716961B2 (en) | 2013-08-10 | 2017-07-25 | Advanced Acoustic Sf Gmbh | Wave field synthesis system |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AUPN003894A0 (en) * | 1994-12-13 | 1995-01-12 | Xenotech Research Pty Ltd | Head tracking system for stereoscopic display apparatus |
| CN1040096C (en) * | 1995-08-17 | 1998-10-07 | 郑州乐喜施磷复肥技术研究推广中心 | Releasion controlled fertilizer |
| DE29518155U1 (en) | 1995-11-16 | 1996-01-11 | Göttfert Küchentechnik, 74392 Freudental | Kitchen appliance |
| FR2787799B1 (en) * | 1998-12-23 | 2001-03-09 | Rhodia Chimie Sa | COMPOSITION COMPRISING AN INORGANIC BARK AND A CORE COMPRISING AT LEAST ONE POLYHYDROXYL COMPOUND |
| FR2801810B1 (en) * | 1999-12-07 | 2002-05-03 | Rhodia Food S A S | CAPSULE COMPRISING AT LEAST ONE MINERAL BARK CONSISTING OF A UNIQUE CHEMICAL COMPOUND AND A CORE COMPRISING AT LEAST ONE POLYHYDROXYL COMPOUND |
| DE102014100026A1 (en) * | 2014-01-02 | 2015-07-02 | Chemische Fabrik Budenheim Kg | Mixed-metallic crystalline orthophosphates for the time-controlled release of trace elements in rhizodermal and epidermal areas of plants |
| WO2024105570A1 (en) * | 2022-11-14 | 2024-05-23 | SABIC Agri-Nutrients Company | Method for multi-phase preparation of complex mineral fertilizer from phosphate rock and nitric acid |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3378363A (en) * | 1965-02-23 | 1968-04-16 | Shell Oil Co | Method of imparting hardness on water-soluble particles |
| US5152821A (en) * | 1988-02-01 | 1992-10-06 | Hi-Fert Pty. Ltd. | Addition of supplemental macro & micro nutrients to granular phosphatic fertilizers |
-
1992
- 1992-06-30 IL IL10237092A patent/IL102370A/en not_active IP Right Cessation
-
1993
- 1993-06-30 AU AU45071/93A patent/AU4507193A/en not_active Abandoned
- 1993-06-30 WO PCT/GB1993/001370 patent/WO1994000405A1/en not_active Application Discontinuation
- 1993-06-30 EP EP93914848A patent/EP0648198A1/en not_active Ceased
Non-Patent Citations (1)
| Title |
|---|
| See references of WO9400405A1 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9716961B2 (en) | 2013-08-10 | 2017-07-25 | Advanced Acoustic Sf Gmbh | Wave field synthesis system |
Also Published As
| Publication number | Publication date |
|---|---|
| AU4507193A (en) | 1994-01-24 |
| IL102370A0 (en) | 1993-01-14 |
| IL102370A (en) | 1995-03-30 |
| WO1994000405A1 (en) | 1994-01-06 |
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