WO2001077019A2 - A process for the production of potassium nitrate - Google Patents
A process for the production of potassium nitrate Download PDFInfo
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- WO2001077019A2 WO2001077019A2 PCT/IL2001/000327 IL0100327W WO0177019A2 WO 2001077019 A2 WO2001077019 A2 WO 2001077019A2 IL 0100327 W IL0100327 W IL 0100327W WO 0177019 A2 WO0177019 A2 WO 0177019A2
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- Prior art keywords
- solution
- nitrate
- magnesium
- ions
- calcium
- Prior art date
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- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 title claims abstract description 81
- 238000000034 method Methods 0.000 title claims abstract description 31
- 235000010333 potassium nitrate Nutrition 0.000 title claims abstract description 24
- 239000004323 potassium nitrate Substances 0.000 title claims abstract description 24
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 9
- 239000000243 solution Substances 0.000 claims abstract description 80
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 claims abstract description 23
- 229910052500 inorganic mineral Inorganic materials 0.000 claims abstract description 22
- 235000010755 mineral Nutrition 0.000 claims abstract description 22
- 239000011707 mineral Substances 0.000 claims abstract description 22
- 239000002244 precipitate Substances 0.000 claims abstract description 19
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910000514 dolomite Inorganic materials 0.000 claims abstract description 17
- 239000010459 dolomite Substances 0.000 claims abstract description 17
- 229910017604 nitric acid Inorganic materials 0.000 claims abstract description 17
- 229910002651 NO3 Inorganic materials 0.000 claims abstract description 14
- ZCCIPPOKBCJFDN-UHFFFAOYSA-N calcium nitrate Chemical compound [Ca+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ZCCIPPOKBCJFDN-UHFFFAOYSA-N 0.000 claims abstract description 14
- 238000001816 cooling Methods 0.000 claims abstract description 14
- 150000002500 ions Chemical class 0.000 claims abstract description 14
- 239000011575 calcium Substances 0.000 claims abstract description 13
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 claims abstract description 12
- PALNZFJYSCMLBK-UHFFFAOYSA-K magnesium;potassium;trichloride;hexahydrate Chemical compound O.O.O.O.O.O.[Mg+2].[Cl-].[Cl-].[Cl-].[K+] PALNZFJYSCMLBK-UHFFFAOYSA-K 0.000 claims abstract description 12
- 239000000203 mixture Substances 0.000 claims abstract description 12
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims abstract description 11
- 239000001103 potassium chloride Substances 0.000 claims abstract description 11
- 235000011164 potassium chloride Nutrition 0.000 claims abstract description 11
- 239000007864 aqueous solution Substances 0.000 claims abstract description 10
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims abstract description 10
- -1 nitrate ions Chemical class 0.000 claims abstract description 10
- 229910001868 water Inorganic materials 0.000 claims abstract description 10
- 239000000395 magnesium oxide Substances 0.000 claims abstract description 9
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 claims abstract description 7
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims abstract description 7
- 239000001095 magnesium carbonate Substances 0.000 claims abstract description 7
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims abstract description 7
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 claims abstract description 6
- 239000000920 calcium hydroxide Substances 0.000 claims abstract description 6
- 229910001861 calcium hydroxide Inorganic materials 0.000 claims abstract description 6
- 239000000292 calcium oxide Substances 0.000 claims abstract description 6
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 claims abstract description 6
- 239000000347 magnesium hydroxide Substances 0.000 claims abstract description 6
- 229910001862 magnesium hydroxide Inorganic materials 0.000 claims abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 6
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims abstract description 5
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 claims abstract description 5
- 239000011591 potassium Substances 0.000 claims abstract description 5
- 229910052700 potassium Inorganic materials 0.000 claims abstract description 5
- 238000005185 salting out Methods 0.000 claims abstract description 5
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims description 19
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 claims description 17
- 238000003756 stirring Methods 0.000 claims description 16
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 14
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 10
- 229910001629 magnesium chloride Inorganic materials 0.000 claims description 9
- UXVMQQNJUSDDNG-UHFFFAOYSA-L Calcium chloride Chemical compound [Cl-].[Cl-].[Ca+2] UXVMQQNJUSDDNG-UHFFFAOYSA-L 0.000 claims description 8
- 239000011780 sodium chloride Substances 0.000 claims description 8
- 239000001110 calcium chloride Substances 0.000 claims description 7
- 229910001628 calcium chloride Inorganic materials 0.000 claims description 7
- 238000001914 filtration Methods 0.000 claims description 4
- 239000006227 byproduct Substances 0.000 claims description 3
- 239000000706 filtrate Substances 0.000 claims description 2
- 239000012535 impurity Substances 0.000 claims description 2
- 238000000926 separation method Methods 0.000 claims description 2
- 230000001376 precipitating effect Effects 0.000 claims 1
- 229910052791 calcium Inorganic materials 0.000 abstract description 7
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 abstract description 4
- 108091006629 SLC13A2 Proteins 0.000 abstract 1
- 239000011777 magnesium Substances 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- 229910052749 magnesium Inorganic materials 0.000 description 5
- 239000000843 powder Substances 0.000 description 5
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 3
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 3
- 150000004679 hydroxides Chemical class 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000008346 aqueous phase Substances 0.000 description 2
- 239000003337 fertilizer Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 229910001414 potassium ion Inorganic materials 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 229910013724 M(OH)2 Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000012074 organic phase Substances 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D9/00—Nitrates of sodium, potassium or alkali metals in general
- C01D9/04—Preparation with liquid nitric acid
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D9/00—Nitrates of sodium, potassium or alkali metals in general
- C01D9/08—Preparation by double decomposition
- C01D9/12—Preparation by double decomposition with nitrates or magnesium, calcium, strontium, or barium
Definitions
- the present invention relates to a process for the production of potassium nitrate (KNO 3 ) by the salting-out of KNO 3 through cooling of a solution which essentially contains the ions K + , Cl , M ++ and N0 3 , wherein M ++ represents Ca " ⁇ and/or Mg ⁇ .
- the process according to the present invention is carried out in aqueous phase and is characterized by the addition of calcium carbonate or magnesium carbonate or magnesium oxide or calcium oxide or magnesium hydroxide or calcium hydroxide or dolomite (Ca » MgC0 3 ), to aqueous solution of potassium chloride and nitric acid.
- the addition of said minerals and cooling cause KNO 3 to crystallize and salt-out of the solution.
- the M ++ and nitrate ions can be obtained from calcium nitrate and/or magnesium nitrate.
- the potassium chloride is added to the mixture in the form of carnallite (KCl-MgCl 2 -6H 2 O), sylvinite (KCl-NaCl), and mixtures containing KC1 and CaCl 2 and/or MgCl 2 and/or NaCL
- Potassium nitrate has various agricultural and industrial applications. It is a very important potassium fertilizer and is used extensively as raw material for the dying and explosive industries. It is also used in technical baths for elevated temperatures. Most of the potassium nitrate in the market is industrially manufactured.
- reaction 2 does not result in KNO 3 precipitation but in a solution containing the ions K + , NO 3 , H + and Cl . Therefore, if the process is carried out in solution it is usually carried out with excess of nitric acid in order to drive the reaction forward, and additional materials and steps are needed to enable the precipitation of the desired mineral from the aqueous solution and to recycle the excess acid.
- Such steps involve the addition of an organic phase such as disclosed in US4364914 and US437834 and GB2217700.
- non-simple apparatus such as an apparatus for negative pressure and elevated temperatures as disclosed in CNl 064063, or a plurality of resin filled chambers as disclosed in US5110578 which is based on ion exchange method.
- the present invention provides a simple and facile method for the preparation of potassium nitrate from potassium chloride and nitric acid in stoicheiometric ratio, which involves simple equipment and only abundant and low-cost raw materials.
- the method according to present invention is carried out in aqueous phase without the addition of any organic solvent and without the need for sophisticated equipment.
- the method for the preparation of potassium nitrate according to the present invention is based on salting out of potassium nitrate from an aqueous solution containing the ions K + , Cl , N0 3 and IVf ⁇ " , wherein Iv represents Ca " ⁇ and/or
- the source of said ions is not important as long as approximately stoichometric ratio between the potassium and nitrate ions is obtained.
- the minerals from which the solution is prepared can be selected according to their abundance and cost.
- the present invention is characterized by the addition of carbonates or oxides or hydroxides of calcium or magnesium, or dolomite, or a combination thereof, (i.e, CaC0 3 or MgC0 3 or CaO or MgO or Ca(OH) 2 or Mg(OH) 2 or dolomite - CaC0 3 «MgC0 3 ) to a solution containing HNO 3 and KC1 in approximately stoicheiometric ratio.
- the addition of these minerals which are all naturally occurred abundant minerals, causes, upon cooling, the precipitation of potassium nitrate from the solution.
- KC1 can be added to the solution not as pure potassium chloride but as raw carnallite (KCl-MgCl 2 -6H 2 0) or sylvinite (KCl-NaCl), or mixtures containing KC1, and NaCl and/or MgCl 2 and/or CaCl 2 , which are very abundant natural occurring minerals and also the principal components of many salt deposits.
- Sylvinite and carnallite are also a by-product in the salt in dustry and the last deposition in stage by stage evaporation in salt lakes such as in the Dead Sea.
- Sylvinite and carnallite are one of the main sources for KC1 and using it as it is, without the need to firstly separate the KC1 provides a process which is simpler and saves costs and energy.
- the M* ' and nitrate ions can be obtained from calcium nitrate and/or magnesium nitrate.
- the present invention relates to a short and facile process for the preparation of potassium nitrate characterized by the preparation of an aqueous solution at temperature higher than 40 °C, containing the ions K + , Cl , M " " and N0 3 wherein M ++ represents Ca -* " and/or Mg ⁇ , and obtaining precipitate of the potassium nitrate by cooling said solution
- the method of the present invention comprises the following steps:
- step (b) dissolving at least one source for potassium chloride, in the solution obtained at step (a) at temperature higher than 40°C, wherein the amount of said source is chosen such as to obtain an approximately stoicheiometric ratio between potassium and nitrate ions and wherein said source is selected from the group consisting of KC1, carnallite, sylvinite, and a mixture of KC1 with MgCl 2 , NaCl, CaCl 2 or a combination thereof;
- step (c) cooling the solution obtained at step (b) to obtain a precipitate of potassium nitrate.
- the method according to the present invention can be carried out as a continuous process or in batch.
- the concentration of the nitrate and potassium ions in the initial hot solution is in the range 0.5 to 8N, preferably in the range 3-6 N (N being the concentration in equivalents per liter solution).
- the method according to the present invention can further comprise the production of magnesium chloride (MgCl 2 ) or of calcium chloride (CaCl 2 ) as a by-product from the filtrate solution obtained after the separation of KNO 3
- the method according to the present invention is based on salting out of potassium nitrate from an aqueous solution containing approximately equivalent amounts of the ions K + , Cl , NO 3 and M “ " , wherein M " " represents Ca " ⁇ and/or
- Mg "1-1" which results from oxides, hydroxides or carbonates of magnesium and/or calcium.
- the first step to obtain such a solution is by dissolving carbonates or oxides or hydroxides of calcium or magnesium, or dolomite, in aqueous solution of HN0 3 ; followed by dissolving an equivalent amount of KC1.
- Reactions 3 - 5 are exothermic reactions resulting in elevation of the solution temperature.
- the aqueous solution contains the ions K + , Cl , Ca ++ and/or
- the hot solution is filtered to filter out impurities and then cooled to 0 - 10°C,
- the pure mineral usually of more than 96% purity, is obtained by separating from solution.
- the potassium nitrate so obtained can be further purified by known techniques such as rinsing with water or with potassium nitrate solution, to obtained purity of more than 98% for use as fertilizer or by re-crystallization to obtain technical grade potassium nitrate with purity higher than 99.8%.
- the first step of preparing the solution is by dissolving calcium nitrate and/or magnesium nitrate in water, then dissolving in the obtained solution a mineral or a mixture of minerals, being a source for potassium chloride in an amount which provides a solution of approximately equivalent concentrations of nitrate and potassium ions.
- the source for the KC1 can be selected from KC1 of different purity grades, carnallite, sylvinite, or it can be a mixture of KC1 with MgCl 2 and/or NaCl and/or CaCl 2 .
- HN0 3 HN0 3
- dolomite powder (96% purity) was added to 102 g of 25% HN0 3 solution under continuous stirring.
- 48 g of sylvinite (30 g KC1 + 15 g NaCl + 2 g H 2 0) were added to the dolomite hot solution (76-78°C) with continuous stirring. After the sylvinite dissolved completely, the solution was cooled to 6°C. 39.6 g of KN0 3 precipitate was obtained.
- dolomite powder (96% purity) was added to 102 g of 25% HN0 3 solution under continuous stirring.
- I l l g of carnallite (30 g KC1 + 38 g MgCl 2 + 43.2 g H 2 O) were added to the dolomite hot solution (80°C) with continuous stirring. After the carnallite dissolved completely, the solution was cooled to 20°C. 39 g of KNO 3 precipitate was obtained.
- dolomite powder (94.7% purity) was added to 102 g of 25% HNO 3 solution under continuous stirring.
- Examples 6-8, and 10-11 demonstrate that under appropriate conditions neither an excess of the ions Cl , M ++ , nor the presence of Na + , interfere with the process.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Agronomy & Crop Science (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Inorganic Chemistry (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
Abstract
A method for the production of potassium nitrate by its salting out from an aqueous solution comprising the ions K?+, C1-, M++¿ and NO¿3?- wherein M++ represents Ca++ and/or Mg++, comprising the following steps; (a) dissolving at least one mineral selected from the group consisting of calcium carbobate, magnesium carbonate, magnesium oxide, calcium oxide, calcium hydroxide, magnesium hydroxide and dolomite, in aqueous nitric acid, in an amount which is approximately stoichiometrically equivalent to the amount of nitrate ions in the solution, or dissolving at least one mineral selected from the group consisting of calcium nitrate and magnesium nitrate, in water; (b) dissolving at least one source for potassium chloride, in the solution obtained at step (a) at temperature higher than 40 °C, wherein the amount of the source is chosen such as to obtain an approximately stoichiometric ratio between potassium and nitrate ions and wherein the source is selected from the group consisting of KC1, carnallite, sylvinite, and a mixture of KC1 with MgC1¿2?, NaC1, CaC12 or a combination thereof; (c) cooling the solution obtained at step (b) to obtain a precipitate of potassium nitrate.
Description
A PROCESS FOR THE PRODUCTION OF POTASSIUM NITRATE
Field of the invention
The present invention relates to a process for the production of potassium nitrate (KNO3) by the salting-out of KNO3 through cooling of a solution which essentially contains the ions K+, Cl , M++ and N03 , wherein M++ represents Ca"^ and/or Mg^. The process according to the present invention is carried out in aqueous phase and is characterized by the addition of calcium carbonate or magnesium carbonate or magnesium oxide or calcium oxide or magnesium hydroxide or calcium hydroxide or dolomite (Ca»MgC03), to aqueous solution of potassium chloride and nitric acid. The addition of said minerals and cooling cause KNO3 to crystallize and salt-out of the solution. In another embodiment of the present invention the M++ and nitrate ions can be obtained from calcium nitrate and/or magnesium nitrate. In another embodiment, the potassium chloride is added to the mixture in the form of carnallite (KCl-MgCl2-6H2O), sylvinite (KCl-NaCl), and mixtures containing KC1 and CaCl2 and/or MgCl2 and/or NaCL
Background of the invention
Potassium nitrate has various agricultural and industrial applications. It is a very important potassium fertilizer and is used extensively as raw material for the dying and explosive industries. It is also used in technical baths for elevated temperatures. Most of the potassium nitrate in the market is industrially manufactured.
There are two main routes for the production of potassium nitrate. One is by the reaction between sodium nitrate and potassium chloride:
1) KC1 + NaNO3 → KN03 + NaCl
The second route is based on the reaction between potassium chloride and nitric acid:
2) KC1 + HN03 → KNO3 + HC1
However, in aqueous media, under stoicheiometric proportions, reaction 2 does not result in KNO3 precipitation but in a solution containing the ions K+, NO3 , H+ and Cl . Therefore, if the process is carried out in solution it is usually carried out with excess of nitric acid in order to drive the reaction forward, and additional materials and steps are needed to enable the precipitation of the desired mineral from the aqueous solution and to recycle the excess acid. Such steps involve the addition of an organic phase such as disclosed in US4364914 and US437834 and GB2217700. Other methods which do not involve an organic solvent, involve non-simple apparatus such as an apparatus for negative pressure and elevated temperatures as disclosed in CNl 064063, or a plurality of resin filled chambers as disclosed in US5110578 which is based on ion exchange method.
The present invention provides a simple and facile method for the preparation of potassium nitrate from potassium chloride and nitric acid in stoicheiometric ratio, which involves simple equipment and only abundant and low-cost raw materials. The method according to present invention is carried out in aqueous phase without the addition of any organic solvent and without the need for sophisticated equipment.
The method for the preparation of potassium nitrate according to the present invention is based on salting out of potassium nitrate from an aqueous solution containing the ions K+, Cl , N03 and IVf^", wherein Iv represents Ca"^ and/or
Mg^ .
According to the method of the present invention the source of said ions is not important as long as approximately stoichometric ratio between the potassium and nitrate ions is obtained. Thus according to the present invention, the
minerals from which the solution is prepared can be selected according to their abundance and cost.
The present invention is characterized by the addition of carbonates or oxides or hydroxides of calcium or magnesium, or dolomite, or a combination thereof, (i.e, CaC03 or MgC03 or CaO or MgO or Ca(OH)2 or Mg(OH)2 or dolomite - CaC03«MgC03 ) to a solution containing HNO3 and KC1 in approximately stoicheiometric ratio. The addition of these minerals, which are all naturally occurred abundant minerals, causes, upon cooling, the precipitation of potassium nitrate from the solution.
Furthermore, KC1 can be added to the solution not as pure potassium chloride but as raw carnallite (KCl-MgCl2-6H20) or sylvinite (KCl-NaCl), or mixtures containing KC1, and NaCl and/or MgCl2 and/or CaCl2, which are very abundant natural occurring minerals and also the principal components of many salt deposits. Sylvinite and carnallite are also a by-product in the salt in dustry and the last deposition in stage by stage evaporation in salt lakes such as in the Dead Sea. Sylvinite and carnallite are one of the main sources for KC1 and using it as it is, without the need to firstly separate the KC1 provides a process which is simpler and saves costs and energy. This is possible according to the present invention since the other ions present in the mineral are added to the solution anyway, providing that the other minerals added to the hot solution are added in amounts that maintain the equivalent ratios between the ions, i.e., in suitable amounts.
In another embodiment of the present invention the M* ' and nitrate ions can be obtained from calcium nitrate and/or magnesium nitrate.
Summary of the invention
The present invention relates to a short and facile process for the preparation of potassium nitrate characterized by the preparation of an aqueous solution at temperature higher than 40 °C, containing the ions K+, Cl , M" " and N03 wherein M++ represents Ca -*" and/or Mg^ , and obtaining precipitate of the potassium nitrate by cooling said solution
The method of the present invention comprises the following steps:
(a) dissolving at least one mineral selected from the group consisting of calcium carbonate, magnesium carbonate, magnesium oxide, calcium oxide, calcium hydroxide, magnesium hydroxide and dolomite, in aqueous nitric acid, in an amount which is approximately stoicheiometrically equivalent to the amount of nitrate ions in the solution, or dissolving at least one mineral selected from the group consisting of calcium nitrate and magnesium nitrate, in water;
(b) dissolving at least one source for potassium chloride, in the solution obtained at step (a) at temperature higher than 40°C, wherein the amount of said source is chosen such as to obtain an approximately stoicheiometric ratio between potassium and nitrate ions and wherein said source is selected from the group consisting of KC1, carnallite, sylvinite, and a mixture of KC1 with MgCl2, NaCl, CaCl2 or a combination thereof;
(c) cooling the solution obtained at step (b) to obtain a precipitate of potassium nitrate.
The method according to the present invention can be carried out as a continuous process or in batch.
The concentration of the nitrate and potassium ions in the initial hot solution is in the range 0.5 to 8N, preferably in the range 3-6 N (N being the concentration in equivalents per liter solution).
The method according to the present invention can further comprise the production of magnesium chloride (MgCl2) or of calcium chloride (CaCl2) as a by-product from the filtrate solution obtained after the separation of KNO3
Detailed description of the invention
The method according to the present invention is based on salting out of potassium nitrate from an aqueous solution containing approximately equivalent
amounts of the ions K+, Cl , NO3 and M " ", wherein M " " represents Ca"^ and/or
Mg"1-1" which results from oxides, hydroxides or carbonates of magnesium and/or calcium.
According to one embodiment of the present invention the first step to obtain such a solution is by dissolving carbonates or oxides or hydroxides of calcium or magnesium, or dolomite, in aqueous solution of HN03 ; followed by dissolving an equivalent amount of KC1.
In the first step HNO3 reacts with the Mg or Ca containing minerals according to the following reactions:
3) MC03 + 2HN03 ► M 2+ + 2NO3 + C02 + 2H20 or:
4) MO + 2HN03 ►M 2++ 2NO3 + H20 or
5) M(OH)2 + 2HN03 ► M 2++ 2NO3 + 2H20 where M=Ca, Mg, Ca*Mg
Reactions 3 - 5 are exothermic reactions resulting in elevation of the solution temperature.
After adding KCL the aqueous solution contains the ions K+, Cl , Ca++ and/or
Mg""", and N03.
The hot solution is filtered to filter out impurities and then cooled to 0 - 10°C,
Upon cooling potassium nitrate precipitates selectively from the solution. The pure mineral, usually of more than 96% purity, is obtained by separating from solution.
The potassium nitrate so obtained can be further purified by known techniques such as rinsing with water or with potassium nitrate solution, to obtained purity of more than 98% for use as fertilizer or by re-crystallization to obtain technical grade potassium nitrate with purity higher than 99.8%.
According to another embodiment of the present invention the first step of preparing the solution is by dissolving calcium nitrate and/or magnesium nitrate in water, then dissolving in the obtained solution a mineral or a mixture of minerals, being a source for potassium chloride in an amount which provides a solution of approximately equivalent concentrations of nitrate and potassium ions.
The source for the KC1 can be selected from KC1 of different purity grades, carnallite, sylvinite, or it can be a mixture of KC1 with MgCl2 and/or NaCl and/or CaCl2 .
The present invention will be further demonstrated by the following examples. These examples do not intend to limit the scope of the invention.
Example 1
60 g of 12 wt. % nitric acid solution was added to 2.6 g magnesium oxide (98%
MgO). After the magnesium oxide dissolved completely, 8.55 g KC1 is added to the solution with continuous stirring until its full dissolving is obtained. The hot solution is filtered and evaporated to 40 g.
After cooling the solution to 6°C, KN03 crystals precipitate and 9.4 g of
KN03 of 96% purity is received after filtration. The yield (calculated by
HN03) is 81.2%/.
The obtained KN03 is washed with solution of KN03 to receive 98.8% purity.
Example 2
30 g of 24% nitric acid solution is added to 6.0 g of CaC03 (97.6% CaCO3) under continuous stirring. 9.0 g of KC1 is added to the hot solution (about 60°C). After KC1 dissolved completely, the solution is filtered and cooled to 4°C. 10.3 g of KN03 was obtained (86% yield calculated by HNO3). After washing with KNO3 solution, 98.2% purity is obtained.
Example 3
9 g of MgC03 was added under continuous stirring to 50 g of 20% HN03 solution. 14.7 g of KC1 was added to the hot solution until complete dissolution was achieved. The solution was filtered and cooled to 4°C. 18.2 g of KN03 precipitate was obtained. After washing with KN03 solution, the purity is
98.4%.
Example 4
32.8 g of 50% solution of Ca(NO3)2 is heated to 70°C.
15.0 g of KC1 was added to the hot solution under continuous stirring.
Upon cooling to 5°C, 18 g of KN03 precipitate was collected.
Example 5
186 g of dolomite powder (96% purity) was added to 102 g of 25% nitric acid solution under continuous stirring. 30 g of KC1 was added to the hot solution with continuous stirring. After the KC1 dissolved completely, the solution was filtered and cooled to 4°C. 37.4 g of KN03 precipitate was obtained.
Example 6
50.6 g of 25% nitric acid solution is mixed with 2.0 g of magnesium carbonate and filtered. The obtained solution is mixed with 56.0 g carnallite (KCl MgCl2-6H20) at 75°C for 30 min. After cooling the solution to 4°C, 19.8 g precipitate of 94.3% KN03 was obtained.
Example 7
63 g of 20% HN03 solution is mixed with 11.0 g calcium carbonate and filtered. The obtained solution is mixed with 15.3 g KC1 and 12.0 MgCl2-6H20 at 70°C for 30 min. After cooling the solution to 6°C and filtration and drying of the obtained precipitate, 20.5 g dry precipitate of 93.0 % KN03 was obtained.
Example 8
18.8 g of dolomite powder (94.7% purity) were added to 102 g of 25% wt. HN03 solution, under continuous stirring. 30 g of KC1 (99.2%) were added to the obtained solution at 78-80°C with continuous stirring. After the KC1 dissolved completely, the solution was filtered and cooled to 24°C. 32.0 g of KN03 precipitate was obtained.
Example 9
18.6 g dolomite powder (96% purity) was added to 102 g of 25% HN03 solution under continuous stirring. 48 g of sylvinite (30 g KC1 + 15 g NaCl + 2 g H20) were added to the dolomite hot solution (76-78°C) with continuous stirring. After the sylvinite dissolved completely, the solution was cooled to 6°C. 39.6 g of KN03 precipitate was obtained.
Example 10
18.6 g dolomite powder (96% purity) was added to 102 g of 25% HN03 solution under continuous stirring. I l l g of carnallite (30 g KC1 + 38 g MgCl2 + 43.2 g H2O) were added to the dolomite hot solution (80°C) with continuous stirring. After the carnallite dissolved completely, the solution was cooled to 20°C. 39 g of KNO3 precipitate was obtained.
Example 11
18.8 g dolomite powder (94.7% purity) was added to 102 g of 25% HNO3 solution under continuous stirring. A mixture of 30 g KC1 + 32 g MgCl2 + 8 g NaCl + 37 g H2O was added to the hot dolomite solution (80°C) with continuous stirring. After the mixture dissolved completely, the solution was cooled to 12°C. 40 g of KNO3 precipitate was obtained.
Examples 6-8, and 10-11 demonstrate that under appropriate conditions neither an excess of the ions Cl , M++ , nor the presence of Na+, interfere with the process.
Claims
1) A method for the production of potassium nitrate by its salting out from an aqueous solution comprising the ions K+, Cl , M"' and N03 wherein M*~+ represents Ca ^ and/or Mg++ , comprising the following steps;
(a) dissolving at least one mineral selected from the group consisting of calcium carbonate, magnesium carbonate, magnesium oxide, calcium oxide, calcium hydroxide, magnesium hydroxide and dolomite, in aqueous nitric acid, in an amount which is approximately stoicheiometrically equivalent to the amount of nitrate ions in the solution, or dissolving at least one mineral selected from the group consisting of calcium nitrate and magnesium nitrate, in water;
(b) dissolving at least one source for potassium chloride, in the solution obtained at step (a) at temperature higher than 40°C, wherein the amount of said source is chosen such as to obtain an approximately stoicheiometric ratio between potassium and nitrate ions and wherein said source is selected from the group consisting of KC1, carnallite, sylvinite, and a mixture of KC1 with MgCl2, NaCl, CaCl2 or a combination thereof;
(c) cooling the solution obtained at step (b) to obtain a precipitate of potassium nitrate.
2) A method according to claim 1 further comprising filtering the hot aqueous solution before cooling, to filter out impurities.
3) A method according to claim 1 carried out under continuous conditions.
4) A method according to claim 1 carried out in batch.
5) A method according to claim 1 wherein the calcium carbonate or magnesium carbonate or dolomite are in their natural form.
6) A method according to claim 1 wherein the initial temperature of the solution is in the range 50-80° and the solution is cooled to 0-30°, preferably to 0-10°.
7) A method according to claim 1 wherein the concentration of the ions in the solution is in the range 0.5 to 8 N.
8) A method according to claim 1 wherein the concentration of ions in the solution is in the range 3 to 6 N.
9) A method according to claim 1 wherein the concentration of the nitric acid solution is in the range 10 - 40 wt. %
10) A method according to claim 1 further comprising the production of MgCl2 or CaCl2 as a by-product, by precipitating MC12 from the filtrate solution that remains after the separation of KN03.
11) A method for the production of potassium nitrate according to claim 1 comprising the following steps;
a) dissolving under continuous stirring at least one mineral selected from the group consisting of calcium carbonate, magnesium carbonate, magnesium oxide, calcium oxide, calcium hydroxide, magnesium hydroxide or dolomite, in nitric acid solution of 10 - 40 wt.%, wherein the amount of said mineral is approximately stoicheiometrically equivalent to the amount of nitrate ions in the solution;
b) adding to the solution obtained in step (a) an equivalent amount of a mineral or a mixture of minerals selected from the group consisting of KC1, carnallite, sylvinite, a mixture of KC1 with MgCl2 and/or CaCl2 and/or NaCl, under continuos stirring and at temperatures in the range of 40-80°C; c) filtering the solution; d) cooling the solution to 0-30°C, preferably 0-10°C, to let potassium nitrate crystallize and precipitate; e) separating and collecting the potassium nitrate precipitate. f) optionally rinsing the precipitate with water or with KN03 solution to obtain higher purity.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU50605/01A AU5060501A (en) | 2000-04-12 | 2001-04-05 | A process for the production of potassium nitrate |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IL135611 | 2000-04-12 | ||
| IL13561100A IL135611A0 (en) | 2000-04-12 | 2000-04-12 | A process for the production of potassium nitrate |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2001077019A2 true WO2001077019A2 (en) | 2001-10-18 |
| WO2001077019A3 WO2001077019A3 (en) | 2002-02-07 |
Family
ID=11074049
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/IL2001/000327 WO2001077019A2 (en) | 2000-04-12 | 2001-04-05 | A process for the production of potassium nitrate |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU5060501A (en) |
| IL (1) | IL135611A0 (en) |
| WO (1) | WO2001077019A2 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1301215C (en) * | 2005-02-25 | 2007-02-21 | 湖南理工学院 | Technological process of preparing potassium nitrate and magnesium chloride |
| CN1302992C (en) * | 2005-09-06 | 2007-03-07 | 张罡 | Method for making potassium nitrate using magnesium hydroxide circular reaction method |
| CN1318303C (en) * | 2005-08-08 | 2007-05-30 | 张罡 | Method for preparing potassium nitrate using nitric acid conversion methdo |
| RU2393117C1 (en) * | 2008-12-22 | 2010-06-27 | Закрытое акционерное общество "Завод "БИНИТ" | Method of producing potassium nitrate and magnesium chloride from potassium chloride and magnesium nitrate |
| CN106629783A (en) * | 2016-10-13 | 2017-05-10 | 张宏善 | Potassium nitrate preparation method |
| CN110862101A (en) * | 2019-12-25 | 2020-03-06 | 安徽胜达化工科技有限公司 | Preparation method of potassium nitrate |
| TWI716267B (en) | 2020-01-20 | 2021-01-11 | 中國石油化學工業開發股份有限公司 | Purification method for purifying 2,4-bis(phenylsulfonyl)phenol |
| CN112875728A (en) * | 2021-02-07 | 2021-06-01 | 武汉世吉药业有限公司 | Preparation method of high-purity potassium nitrate and high-purity potassium nitrate |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108439435A (en) * | 2018-03-24 | 2018-08-24 | 山东天化学股份有限公司 | A kind of method that direct method prepares potassium nitrate |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3433584A (en) * | 1966-03-07 | 1969-03-18 | St Paul Ammonia Products Inc | Production of potassium nitrate from calcium nitrate |
| GB1313926A (en) * | 1969-05-22 | 1973-04-18 | Montedison Spa | Preparation of potassium nitrate |
| IL53431A (en) * | 1977-11-21 | 1980-12-31 | Israel Chemicals Ltd | Process for the production of potassium nitrate |
| CS276859B6 (en) * | 1990-08-09 | 1992-08-12 | Anton Dipl Tech Pavlotty | A method of producing potassium nitrate |
| CN1043750C (en) * | 1995-08-31 | 1999-06-23 | 夏文建 | Process for producing potassium nitrate |
-
2000
- 2000-04-12 IL IL13561100A patent/IL135611A0/en unknown
-
2001
- 2001-04-05 AU AU50605/01A patent/AU5060501A/en not_active Abandoned
- 2001-04-05 WO PCT/IL2001/000327 patent/WO2001077019A2/en active Application Filing
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1301215C (en) * | 2005-02-25 | 2007-02-21 | 湖南理工学院 | Technological process of preparing potassium nitrate and magnesium chloride |
| CN1318303C (en) * | 2005-08-08 | 2007-05-30 | 张罡 | Method for preparing potassium nitrate using nitric acid conversion methdo |
| CN1302992C (en) * | 2005-09-06 | 2007-03-07 | 张罡 | Method for making potassium nitrate using magnesium hydroxide circular reaction method |
| RU2393117C1 (en) * | 2008-12-22 | 2010-06-27 | Закрытое акционерное общество "Завод "БИНИТ" | Method of producing potassium nitrate and magnesium chloride from potassium chloride and magnesium nitrate |
| CN106629783A (en) * | 2016-10-13 | 2017-05-10 | 张宏善 | Potassium nitrate preparation method |
| CN110862101A (en) * | 2019-12-25 | 2020-03-06 | 安徽胜达化工科技有限公司 | Preparation method of potassium nitrate |
| TWI716267B (en) | 2020-01-20 | 2021-01-11 | 中國石油化學工業開發股份有限公司 | Purification method for purifying 2,4-bis(phenylsulfonyl)phenol |
| CN113135847A (en) * | 2020-01-20 | 2021-07-20 | 中国石油化学工业开发股份有限公司 | Purification method of 2, 4-diphenylsulfuryl phenol |
| CN112875728A (en) * | 2021-02-07 | 2021-06-01 | 武汉世吉药业有限公司 | Preparation method of high-purity potassium nitrate and high-purity potassium nitrate |
Also Published As
| Publication number | Publication date |
|---|---|
| AU5060501A (en) | 2001-10-23 |
| WO2001077019A3 (en) | 2002-02-07 |
| IL135611A0 (en) | 2001-05-20 |
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