CA3111115A1 - An industrial process and a system for production of potassium and potassium magnesium fertilizers - Google Patents
An industrial process and a system for production of potassium and potassium magnesium fertilizers Download PDFInfo
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- CA3111115A1 CA3111115A1 CA3111115A CA3111115A CA3111115A1 CA 3111115 A1 CA3111115 A1 CA 3111115A1 CA 3111115 A CA3111115 A CA 3111115A CA 3111115 A CA3111115 A CA 3111115A CA 3111115 A1 CA3111115 A1 CA 3111115A1
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- sulfate
- potassium
- khso4
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 50
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 title claims abstract description 46
- 229910052700 potassium Inorganic materials 0.000 title claims abstract description 46
- 239000011591 potassium Substances 0.000 title claims abstract description 46
- 239000003337 fertilizer Substances 0.000 title claims description 13
- SWHAQEYMVUEVNF-UHFFFAOYSA-N magnesium potassium Chemical compound [Mg].[K] SWHAQEYMVUEVNF-UHFFFAOYSA-N 0.000 title description 5
- CHKVPAROMQMJNQ-UHFFFAOYSA-M potassium bisulfate Chemical compound [K+].OS([O-])(=O)=O CHKVPAROMQMJNQ-UHFFFAOYSA-M 0.000 claims abstract description 200
- 229910000343 potassium bisulfate Inorganic materials 0.000 claims abstract description 200
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 186
- CSNNHWWHGAXBCP-UHFFFAOYSA-L Magnesium sulfate Chemical compound [Mg+2].[O-][S+2]([O-])([O-])[O-] CSNNHWWHGAXBCP-UHFFFAOYSA-L 0.000 claims abstract description 155
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 119
- OTYBMLCTZGSZBG-UHFFFAOYSA-L potassium sulfate Chemical compound [K+].[K+].[O-]S([O-])(=O)=O OTYBMLCTZGSZBG-UHFFFAOYSA-L 0.000 claims abstract description 107
- 229910052939 potassium sulfate Inorganic materials 0.000 claims abstract description 106
- 229910052943 magnesium sulfate Inorganic materials 0.000 claims abstract description 76
- 235000019341 magnesium sulphate Nutrition 0.000 claims abstract description 76
- 235000011151 potassium sulphates Nutrition 0.000 claims abstract description 71
- TWRXJAOTZQYOKJ-UHFFFAOYSA-L Magnesium chloride Chemical compound [Mg+2].[Cl-].[Cl-] TWRXJAOTZQYOKJ-UHFFFAOYSA-L 0.000 claims abstract description 43
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 claims abstract description 32
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000011777 magnesium Substances 0.000 claims abstract description 29
- 229910052749 magnesium Inorganic materials 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 28
- 229910001629 magnesium chloride Inorganic materials 0.000 claims abstract description 21
- 239000000706 filtrate Substances 0.000 claims abstract description 19
- 239000002253 acid Substances 0.000 claims abstract description 13
- 238000001556 precipitation Methods 0.000 claims abstract description 13
- 238000010924 continuous production Methods 0.000 claims abstract description 12
- 238000011084 recovery Methods 0.000 claims abstract description 12
- 238000004821 distillation Methods 0.000 claims abstract description 9
- 230000035484 reaction time Effects 0.000 claims abstract description 8
- 238000002425 crystallisation Methods 0.000 claims abstract description 5
- 230000008025 crystallization Effects 0.000 claims abstract description 5
- 238000004064 recycling Methods 0.000 claims abstract description 5
- 239000000243 solution Substances 0.000 claims description 41
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 34
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 26
- 229940072033 potash Drugs 0.000 claims description 26
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Substances [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 26
- 235000015320 potassium carbonate Nutrition 0.000 claims description 26
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 25
- 235000011147 magnesium chloride Nutrition 0.000 claims description 19
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 claims description 18
- 235000011149 sulphuric acid Nutrition 0.000 claims description 17
- 238000006243 chemical reaction Methods 0.000 claims description 13
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims description 8
- 238000001704 evaporation Methods 0.000 claims description 8
- 230000008020 evaporation Effects 0.000 claims description 7
- WRUGWIBCXHJTDG-UHFFFAOYSA-L magnesium sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Mg+2].[O-]S([O-])(=O)=O WRUGWIBCXHJTDG-UHFFFAOYSA-L 0.000 claims description 7
- 229940061634 magnesium sulfate heptahydrate Drugs 0.000 claims description 7
- 239000001103 potassium chloride Substances 0.000 claims description 7
- 235000011164 potassium chloride Nutrition 0.000 claims description 7
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 claims description 6
- 238000005187 foaming Methods 0.000 claims description 6
- 229910052938 sodium sulfate Inorganic materials 0.000 claims description 6
- 235000011152 sodium sulphate Nutrition 0.000 claims description 6
- 230000002378 acidificating effect Effects 0.000 claims description 5
- 238000001914 filtration Methods 0.000 claims description 5
- 238000002156 mixing Methods 0.000 claims description 5
- 239000012452 mother liquor Substances 0.000 claims description 5
- 230000001376 precipitating effect Effects 0.000 claims description 5
- 238000003756 stirring Methods 0.000 claims description 5
- 238000007792 addition Methods 0.000 claims description 3
- 239000012047 saturated solution Substances 0.000 claims description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 claims description 2
- 239000000460 chlorine Substances 0.000 claims description 2
- 229910052801 chlorine Inorganic materials 0.000 claims description 2
- 230000000977 initiatory effect Effects 0.000 claims 2
- BNPSSFBOAGDEEL-UHFFFAOYSA-N albuterol sulfate Chemical compound OS(O)(=O)=O.CC(C)(C)NCC(O)C1=CC=C(O)C(CO)=C1.CC(C)(C)NCC(O)C1=CC=C(O)C(CO)=C1 BNPSSFBOAGDEEL-UHFFFAOYSA-N 0.000 claims 1
- 230000003472 neutralizing effect Effects 0.000 claims 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 9
- 150000003467 sulfuric acid derivatives Chemical class 0.000 description 6
- 239000000395 magnesium oxide Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 239000000391 magnesium silicate Substances 0.000 description 3
- 229910052919 magnesium silicate Inorganic materials 0.000 description 3
- 235000019792 magnesium silicate Nutrition 0.000 description 3
- ZADYMNAVLSWLEQ-UHFFFAOYSA-N magnesium;oxygen(2-);silicon(4+) Chemical compound [O-2].[O-2].[O-2].[Mg+2].[Si+4] ZADYMNAVLSWLEQ-UHFFFAOYSA-N 0.000 description 3
- 239000011541 reaction mixture Substances 0.000 description 3
- 239000007832 Na2SO4 Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000009825 accumulation Methods 0.000 description 2
- 230000003247 decreasing effect Effects 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 239000010425 asbestos Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- WZISDKTXHMETKG-UHFFFAOYSA-H dimagnesium;dipotassium;trisulfate Chemical compound [Mg+2].[Mg+2].[K+].[K+].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O WZISDKTXHMETKG-UHFFFAOYSA-H 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 238000005453 pelletization Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 229910052895 riebeckite Inorganic materials 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 239000000741 silica gel Substances 0.000 description 1
- 229910002027 silica gel Inorganic materials 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 230000001954 sterilising effect Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- 239000011593 sulfur Substances 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05D—INORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C; FERTILISERS PRODUCING CARBON DIOXIDE
- C05D1/00—Fertilisers containing potassium
- C05D1/02—Manufacture from potassium chloride or sulfate or double or mixed salts thereof
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
- C01D5/02—Preparation of sulfates from alkali metal salts and sulfuric acid or bisulfates; Preparation of bisulfates
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D5/00—Sulfates or sulfites of sodium, potassium or alkali metals in general
- C01D5/12—Preparation of double sulfates of magnesium with sodium or potassium
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F5/00—Compounds of magnesium
- C01F5/40—Magnesium sulfates
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05D—INORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C; FERTILISERS PRODUCING CARBON DIOXIDE
- C05D1/00—Fertilisers containing potassium
-
- C—CHEMISTRY; METALLURGY
- C05—FERTILISERS; MANUFACTURE THEREOF
- C05D—INORGANIC FERTILISERS NOT COVERED BY SUBCLASSES C05B, C05C; FERTILISERS PRODUCING CARBON DIOXIDE
- C05D5/00—Fertilisers containing magnesium
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
A process comprising producing potassium hydrogen sulfate from KCI using reactors in cascade, using an excess of sulfuric acid, in a continuous process; precipitation of potassium sulfate (SOP) under controlled temperature, ratio of wet methanol to potassium acid sulfate and reaction time; production of magnesium sulfate by reacting acid recovered from the production of potassium acid sulfate with calcined tailings, in wet methanol, thereby eliminating acid prior to recovery of methanol by distillation, allowing recovery of potassium values of entities unreacted previously, in absence of cavitation, while recycling magnesium chloride obtained by crystallization of magnesium sulfate to the production of potassium acid sulfate and recovering of potassium values from unreacted KCI and potassium acid sulfate, in a filtrate of the potassium sulfate (SOP), thereby allowing an alternate direct access to sulfate of potassium and magnesium (SOPM) by reacting potassium acid sulfate with calcined tailings and sulfuric acid.
Description
I
TITLE OF THE INVENTION
An industrial process and a system for production of potassium and potassium magnesium fertilizers FIELD OF THE INVENTION
[0001] The present invention relates to potassium and potassium magnesium fertilizers. More specifically, the present invention is concerned with an industrial process and a system for production of potassium and potassium magnesium fertilizers.
BACKGROUND OF THE INVENTION
TITLE OF THE INVENTION
An industrial process and a system for production of potassium and potassium magnesium fertilizers FIELD OF THE INVENTION
[0001] The present invention relates to potassium and potassium magnesium fertilizers. More specifically, the present invention is concerned with an industrial process and a system for production of potassium and potassium magnesium fertilizers.
BACKGROUND OF THE INVENTION
[0002] A number of crops, especially intensive crops, require the use of sulphates fertilizers and potassium additions. Potassium sulfate K2SO4, also referred to as SOP for sulfate of potash, and sulfate of potassium and magnesium K2SO4 2MgSO4, also referred to as SOPM for sulfate of potash-magnesia, are known as chloride (Cl) free fertilizers, providing both potassium and a source of sulfur. Their use allows avoiding accumulation of chloride resulting from the use of potassium chloride (KCI) commonly called potash, which accumulation leads to soils sterilization.
[0003] Production of potassium sulfate K2504 (SOP) and sulfate of potassium and magnesium (SOPM) are typically based on the reaction of sulfuric acid H2SO4 with potash (KCI).
Industrial implementation still faces issues, and current industrial processes and systems still meet operational and economical challenges.
Industrial implementation still faces issues, and current industrial processes and systems still meet operational and economical challenges.
[0004] There is still a need in the art for an industrial process and a system for producing potassium and potassium magnesium fertilizers.
SUMMARY OF THE INVENTION
Date Recue/Date Received 2021-03-02
SUMMARY OF THE INVENTION
Date Recue/Date Received 2021-03-02
[0005] More specifically, in accordance with the present invention, there is provided a process of production of chloride free fertilizers, comprising forming potassium acid sulfate (KHSO4) by reacting potash (KCI) with sulfuric acid (H2SO4); and one of: i) producing potassium sulfate (SOP) by forming a water solution of the formed potassium acid sulfate (KHSO4) and mixing with wet methanol, thereby precipitating potassium sulfate (SOP); and ii) producing potassium sulfate (SOP) by forming a water solution of the formed potassium acid sulfate (KHSO4) and mixing with wet methanol, thereby precipitating potassium sulfate (SOP) and liberating sulfuric acid (H2504), reacting the sulfuric acid (H2SO4) with calcined serpentinic to obtain magnesium sulfate (MgSO4; and combining the magnesium sulfate (MgSO4) with the potassium sulfate (SOP) in a ratio of one potassium sulfate (SOP) for two magnesium sulfate (MgSO4), thereby yielding sulfate of potassium and magnesium (SOPM).
[0006] There is further provided a system for production of chloride free fertilizers, comprising one of: i) an array of reactors in series for a continuous production of potassium hydrogen sulfate (KHSO4) under controlled parameters by reacting potash (KCI) with sulfuric acid (H2504); and a second reactor receiving the formed potassium acid sulfate (KHSO4) and a solution of wet methanol of about 80/20 vol/vol for precipitation of potassium sulfate K2504 (SOP), thereby liberating sulfuric acid (H2504), reacting the sulfuric acid (H2504) with calcined serpentinic to obtain magnesium sulfate (MgSO4); and an array of three reactors in series for a continuous production of potassium hydrogen sulfate (KHSO4) under controlled parameters by reacting potash (KCI) with sulfuric acid (H2SO4); a fourth reactor receiving the formed potassium acid sulfate (KHSO4) and a solution of wet methanol of about 80/20 vol/vol for precipitation of potassium sulfate K2504 (SOP), thereby liberating sulfuric acid (H2SO4), reacting the sulfuric acid (H2SO4) with calcined serpentinic to obtain magnesium sulfate (MgSO4); and a fifth reactor receiving the magnesium sulfate (MgSO4) with the potassium sulfate (SOP), for producing sulfate of potassium and magnesium (SOPM).
[0007] There is further provided a process of production of chloride free fertilizers, comprising producing potassium hydrogen sulfate KHSO4 from KCI under controlled parameters using reactors in cascade, using an excess of acid, at selected temperatures and selected added volumes of water and reaction times in each one of the reactors, in a continuous process; production Date Recue/Date Received 2021-03-02 of potassium sulfate K2SO4 (SOP) by pouring the produced potassium acid sulfate KHSO4 in a wet methanol solution at a selected vol/vol ratio for precipitation of potassium sulfate K2504 (SOP) under controlled temperature, ratio of wet methanol to potassium acid sulfate KHSO4 and reaction time;
yielding a controlled acidic filtrate; production of magnesium sulfate by reacting acid recovered from the production of potassium acid sulfate KHSO4 with calcined tailings, in wet methanol, thereby eliminating acid prior to recovery of methanol by distillation, allowing recovery of potassium values of entities unreacted previously, in absence of cavitation, while recycling magnesium chloride MgCl2 obtained by crystallization of magnesium sulfate MgSO4 to the production of potassium acid sulfate KHSO4 and recovering of potassium values from unreacted KCI and potassium acid sulfate KHSO4, in a filtrate of the potassium sulfate K2SO4 (SOP), thereby allowing a direct access to sulfate of potassium and magnesium (SOPM) by reacting potassium acid sulfate KHSO4 with calcined tailings and sulfuric acid.
yielding a controlled acidic filtrate; production of magnesium sulfate by reacting acid recovered from the production of potassium acid sulfate KHSO4 with calcined tailings, in wet methanol, thereby eliminating acid prior to recovery of methanol by distillation, allowing recovery of potassium values of entities unreacted previously, in absence of cavitation, while recycling magnesium chloride MgCl2 obtained by crystallization of magnesium sulfate MgSO4 to the production of potassium acid sulfate KHSO4 and recovering of potassium values from unreacted KCI and potassium acid sulfate KHSO4, in a filtrate of the potassium sulfate K2SO4 (SOP), thereby allowing a direct access to sulfate of potassium and magnesium (SOPM) by reacting potassium acid sulfate KHSO4 with calcined tailings and sulfuric acid.
[0008] Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In the appended drawings:
[0010] FIG. 1 is a schematic diagram of production of potassium hydrogen sulfate KHSO4according to an embodiment of an aspect of the present invention;
[0011] FIG. 2 is a schematic diagram of preparation of potassium sulfate (SOP) according to an embodiment of an aspect of the present invention;
[0012] FIG. 3 is a schematic diagram of methanol recovery and production of magnesium sulphate MgSO4; and Date Recue/Date Received 2021-03-02
[0013] FIG. 4 is a schematic diagram of production of sulfate of potassium and magnesium (SOPM) according to an embodiment of an aspect of the present invention.
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0014] In a nutshell, there is provided a process and a system for producing potassium sulfate and potassium magnesium sulfate from potassium chloride via potassium acid sulfate KHSO4 precipitation in wet methanol, magnesium being obtained from magnesium silicate.
[0015] As illustrated for example in FIG. 1, an array of three reactors in series is used for a continuous production of potassium hydrogen sulfate KHSO4 under controlled parameters, in a continuous process in which any entrants in a reactor is made to react during their residence time therein.
[0016] A first reactor 1 is fed with sulfuric acid (93% H2504) and potash (97%
potassium chloride KCI) in powder form, with a 3% excess of sulfuric acid H2SO4 is used over the stoYchiometric weight ratio. The reacting mass in the first reactor is heated to a temperature in the range between about 900C and about 1000C and mechanically stirred to achieve homogeneity of the reacting mass and to break foaming generated by the evolution of hydrochloric acid HCI during the reaction of formation of potassium hydrogen sulfate KHSO4as follows:
potassium chloride KCI) in powder form, with a 3% excess of sulfuric acid H2SO4 is used over the stoYchiometric weight ratio. The reacting mass in the first reactor is heated to a temperature in the range between about 900C and about 1000C and mechanically stirred to achieve homogeneity of the reacting mass and to break foaming generated by the evolution of hydrochloric acid HCI during the reaction of formation of potassium hydrogen sulfate KHSO4as follows:
[0017] (Relation 1) KCI + H2504¨> KHSO4+ HCI
[0018] As the reaction (Relation 1) proceeds, the hydrochloric acid gas HCI is collected under a weak vacuum in the range between about 5 and about 10 inches of water; the viscosity of the reacting mass is adjusted by addition of water; in amount in a range between about 9 and 13 %, for exemple of about 11%, of the weight of the feed potash in reactor 1.
[0019] When between about 60 and about 70% of the hydrochloric acid HCI evolution Date Recue/Date Received 2021-03-02 is completed and a residual sulfuric acid H2SO4 of a corresponding decreased concentration is obtained, typically after a residence time of about two hours at the temperature between about 90 and about 100 C, the volume of feed in the first reactor 1, or overflow, is directed to a second reactor 2 by gravity through a heat traced pipe to complete the reaction at a higher temperature, in the range between about 120 and about 125 C, under mechanical stirring. Water is added to the reactor 2 in amount in a range between about 30 and about 35%, for example of about 33% of the initial weight of the feed potash in reactor 1.
[0020] Foaming is decreased under these conditions in the second reactor 2. The hydrochloric acid HCI evolution in the second reactor 2 is accompanied by water distillation, yielding an azeotropic hydrochloric acid distillate at 21% HCI, which boils at the temperature inside the second reactor 2. The resulting HCl/H20 phase is evacuated from the second reactor 2 under weak vacuum in the range between about 5 and about 10 inches of water, combined with the hydrochloric acid gas HCI collected from the first reactor 2, cooled to a temperature in a range between about 5 and 2 C , for example to about 2 C, and condensed to yield a 35% hydrochloric acid HCI.
[0021] The transformation of the reacting mass into potassium acid sulfate KHSO4 after these steps in the first and second reactors 1, 2 is completed at the level of about 95%, with unreacted sulfuric acid and the initial excess, 8% of the initial charge in sulfuric acid H2SO4, and 5%
unreacted potash KCI in solution with the potassium acid sulfate KHSO4.
unreacted potash KCI in solution with the potassium acid sulfate KHSO4.
[0022] After a residence time of about two hours in the second reactor 2 under the conditions described hereinabove, the obtained solution of potassium acid sulfate KHSO4 overflow is directed to a third reactor 3, which is a stirred holding tank, where the concentration and the temperature of the solution are adjusted to optimize precipitation of potassium sulfate (K2 SO4) in methanol/water solution Me0H/H20 as follows:
[0023] (Relation 2) 2KHSO4 + Me0H/H20 ¨> K2SO4+ H2SO4 + Me0H/H20.
[0024] Water is added to the third reactor 3 to reach a solution of potassium acid Date Recue/Date Received 2021-03-02 sulfate KHSO4 of a concentration of potassium acid sulfate KHSO4 between about 85g/100m1 and about 95g/100m1 at a temperature in the range between about 65 and about 70 C.
This well stirred solution is equilibrated in temperature and concentration by a residence time of about one hour in the third reactor 3.
This well stirred solution is equilibrated in temperature and concentration by a residence time of about one hour in the third reactor 3.
[0025] Thus, potassium hydrogen sulfate KHSO4 is produced using reactors in cascade, using an excess of sulfuric acid H2SO4, and selecting specific temperatures, added volumes of water and reaction times in each one of the reactors, to achieve, in a continuous process, efficiency of the conversion of the feed into potassium hydrogen sulfate KHSO4 of up to 95%.
[0026] As illustrated in FIG. 2, the produced solution of acid sulfate KHSO4 in water obtained is transferred to a stirred fourth reactor 4 containing a wet/methanol solution of about 80/20 vol/vol, for precipitation of potassium sulfate K2SO4 (SOP) at a temperature controlled between about 40 and about 45 C. The ratio of wet methanol to potassium acid sulfate is monitored such as to control of the quality of the precipitated potassium sulfate K2SO4 (SOP). A
definite degree of dilution by methanol in the reaction mixture is required to obtain pure potassium sulfate K2SO4 (SOP), with a K/S molar ratio near 2.43 with a potassium content in the potassium sulfate K2504 (SOP) of 43% or more. The ratio of wet methanol to potassium acid sulfate KHSO4 is controlled so as prevent formed potassium sulfate K2504 (SOP) from combining in part with unreacted potassium acid sulfate KHSO
into a mixed salt K2504. KHSO4 Maintaining a ratio between about 1.25 and about 1.75 mole of potassium acid sulfate KHSO4 per liter of wet methanol 80/20 vol/vol allows obtaining a resulting potassium sulfate K2SO4 (SOP) of high degree of purity, with a K/S molar ration in a range between about 2.39 and about 2.44, for example of 2.40.
definite degree of dilution by methanol in the reaction mixture is required to obtain pure potassium sulfate K2SO4 (SOP), with a K/S molar ratio near 2.43 with a potassium content in the potassium sulfate K2504 (SOP) of 43% or more. The ratio of wet methanol to potassium acid sulfate KHSO4 is controlled so as prevent formed potassium sulfate K2504 (SOP) from combining in part with unreacted potassium acid sulfate KHSO
into a mixed salt K2504. KHSO4 Maintaining a ratio between about 1.25 and about 1.75 mole of potassium acid sulfate KHSO4 per liter of wet methanol 80/20 vol/vol allows obtaining a resulting potassium sulfate K2SO4 (SOP) of high degree of purity, with a K/S molar ration in a range between about 2.39 and about 2.44, for example of 2.40.
[0027] After about one hour under good stirring as described hereinabove, the solution is filtered using a belt filter or a drum filter for example, and vapors of the methanol solvent are recovered in a near quantitative recycling thereof as will be described hereinbelow in relation to FIG. 3.
[0028] The potassium sulfate K2SO4 (SOP) cake obtained may be rinsed with fresh Date Recue/Date Received 2021-03-02 wet methanol in a countercurrent mode with a volume corresponding to two to four displacements, dried and directed to physical shaping for market or to production of sulfate of potassium and magnesium K2SO4 2MgSO4 (SOPM), as will be described hereinbelow in relation to FIG. 4.
[0029] The filtrate contains water, methanol and sulfuric acid not reacted during the production of the potassium acid sulfate KHSO4 described hereinabove in relation to FIG. 1 or liberated during the production of potassium sulfate K2SO4 (SOP) in reactor 4, and traces of dissolved or unreacted species, typically as follow, in unit of weight: H20:
45.47; H2504: 8.732;
K2SO4: 0.3725; Potash KCI : 0.6040; KHSO4: 0.1991; NaCI : 0.1015, sodium chloride being an impurity in the potash KCI, and methanol : 44.52.
45.47; H2504: 8.732;
K2SO4: 0.3725; Potash KCI : 0.6040; KHSO4: 0.1991; NaCI : 0.1015, sodium chloride being an impurity in the potash KCI, and methanol : 44.52.
[0030] FIG. 3 illustrates recovering of methanol and production of magnesium sulphate MgSO4, in a sequence of steps allowing eliminating corrosion problems during distillation of the wet methanol 80/20 vol/vol solution.
[0031] Calcined serpentinic tailings are used as a source of MgO for neutralization of the acidic components, i.e. sulfuric acid H2SO4 and potassium acid sulfate KHSO4, of the filtrate obtained by filtration in reactor 4 (see FIG. 2). Serpentinic tailings are calcined at 800 C to remove traces of asbestos fiber and produce very reactive, basic calcined serpentinic of a MgO content of 47.5%. The filtrate is reacted with these calcined tailings in a reactor 5 under stirring to obtain magnesium sulfate MgSO4, as per Relation 3 below. When only two of the three MgO in Relation 3 below are involved, residual magnesium silicate Mg0.25i02 may be readily filtered, without silica gel formation:
[0032] (Relation 3) 3Mg0.25i02 + 2H2 SO4 ¨> 2 MgSO4 + Mg0.25i02 +
[0033] During the reaction in the reactor 5, the small amount of nonreacted potassium acid sulfate KHSO4 in the filtrate is transformed into components which may be directed to the production of sulfate of potassium and magnesium K2SO4 2MgSO4 (SOPM), as will be further described hereinbelow in relation to FIG. 4 and Relation 4. The other components of the filtrate, Date Recue/Date Received 2021-03-02 unreacted potash KCI with traces of NaCI, in the presence of relatively large amounts of magnesium sulphate MgSO4, are transformed into potassium sulfate K2SO4 and sodium sulfate Na2SO4 respectively, in an evaporator, due to the much higher solubility of magnesium chloride MgCl2 compared to the solubility of these two sulfates at the time of evaporation (Relations 5 and 6) :
[0034] (Relation 4) 2 KHSO4 + 3Mg0.2Si02 ¨> K2SO4 + MgSO4 +
2{MgO.Si02} +H20
2{MgO.Si02} +H20
[0035] (Relation 5) 2 KCI + MgSO4 ¨> K2SO4 + MgCl2
[0036] (Relation 6) 2NaCI + MgSO4 ¨> Na2SO4 + MgCl2
[0037] According to an embodiment of the present disclosure, the reaction of the filtrate with the calcined tailings in the reactor 5 is done under stirring the reaction mixture at a temperature in a range between about 70 and about 800C, for example of 75 C, for about two hours, using a reflux condenser to keep the methanol inside the mixture. The mixture is then filtered, rinsed with water (2 volume displacements, countercurrent) in order to recover the methanol, which is redirected to the production of K2SO4 (SOP) after distillation (see FIG. 2), and the solubles from the residual magnesium silicate Mg0.25i02 are passed through an evaporator to obtain, by evaporation, a magnesium sulfate heptahydrate MgSO4.7H20 with some potassium sulfate and traces of sodium sulfate, and magnesium chloride MgCl2 and magnesium sulfate MgSO4 in the mother liquors.
[0038] The mother liquors may be redirected to the production of potassium acid sulfate KHSO4 as described hereinabove in relation to FIG. 1.
[0039] The magnesium sulfate heptahydrate MgSO4.7H20 may be directed to the production of sulfate of potassium and magnesium K2SO4 2MgSO4 (SOPM).
[0040] According to an embodiment of an aspect if the present disclosure as illustrated in the bottom panel of FIG. 4, the magnesium sulfate heptahydrate MgSO4.7H20 is mixed Date Recue/Date Received 2021-03-02 with potassium sulfate K2SO4 (SOP) and dried at about 175 C to give sulfate of potassium and magnesium K2SO4 2MgSO4 (SOPM) as follows:
[0041] (Relation 7) K2SO4 + 2 MgSO4. 7H20 ¨> K2SO4.2 MgSO4. H20 +
[0042] It is found that application of pressure on the dried reaction mixture of sulfates described in Relation 7 produces a compressed material in which completion of the bonding of the sulfates is completed, and thus having specific properties compared to the mere mixture of the two sulfates. Interestingly, the compressed material can be dissolved in water without heat evolution from hydration, as opposed to dissolution of dehydrated magnesium sulfate, which is very exothermic.
Thus, in a method according to an aspect of the present disclosure, at the time of pelletizing the sulfate of potassium and magnesium K2504 2MgSO4 (SOPM), a pressure selected in the range between about 1000 and about 1500 psi is applied to obtain pellets.
Thus, in a method according to an aspect of the present disclosure, at the time of pelletizing the sulfate of potassium and magnesium K2504 2MgSO4 (SOPM), a pressure selected in the range between about 1000 and about 1500 psi is applied to obtain pellets.
[0043] A mother liquor rich in magnesium chloride MgCl2 obtained by crystallization of the magnesium sulfate MgSO4 can be recycled to the first reactor 1 used for the production of potassium acid sulfate KHSO4 (see of FIG. 1). Mixed with the potash KCI feed, it is transformed into hydrochloric acid HCI and magnesium sulfate MgSO4 by the action of the sulfuric acid H2504 as per the following reaction (Relation 8):
[0044] (Relation 8) MgCl2 + H2SO4 ¨> MgSO4 + 2HCI
[0045] In this case, the potassium acid sulfate KHSO4 in the third reactor of FIG. 1 is then tainted with some magnesium sulphate MgSO4. This potassium acid sulfate KHSO4 tainted with magnesium sulphate MgSO4 is used for direct production of sulfate of potassium and magnesium K2SO4 2MgSO4 (SOPM) as suggested by Relation 4 as mentioned hereinabove, which describes the recovery of potassium values, in the form of unreacted potassium acid sulfate KHSO4 (relations 4, 11), in the filtrate of potassium sulfate K2SO4 (SOP) (see hereinabove):
Date Recue/Date Received 2021-03-02
Date Recue/Date Received 2021-03-02
[0046] (Relation 11) K2SO4+ 2MgSO4 ¨> K2 SO4 .2MgSO4
[0047] In Relation 11, sulfate of magnesium is combined with sulfate of potassium to obtain sulfate of potassium and magnesium K2 SO4 .2MgSO4 (SOPM).
[0048] According to an embodiment of an aspect of the present disclosure as illustrated in the top panel of FIG. 4, in case larger amounts of sulfate of potassium and magnesium K2SO4 2MgSO4 (SOPM) are targeted and/or in case it is not desirable to use the potassium sulfate K2SO4 (SOP) to produce sulfate of potassium and magnesium K2504 2MgSO4 (SOPM) as per Relation 7 hereinabove for example, the production of sulfate of potassium and magnesium K2504 2MgSO4 (SOPM) is performed directly from potassium acid sulfate KHSO4 produced as described in relation to FIG. 1 hereinabove, by reacting potassium acid sulfate KHSO4 with calcined tailings and sulfuric acid recovered from the production step of potassium acid sulfate KHSO4 (see FIG. 1), as per Relation 9:
[0049] (Relation 9) 2KHSO4 + H2SO4 + 3Mg0.2Si02 ¨> K2SO4.2MgSO4.H20 +
Mg0.2Si02 +H20
Mg0.2Si02 +H20
[0050] This reaction proceeds readily and quantitatively with a contact time of about two hours under stirring at a temperature in the range between about 75 and about 80 C followed by filtration and evaporation at about 175 C.
[0051] As people in the art will now be in a position to appreciate, there is thus presented a process comprising : production of potassium hydrogen sulfate KHSO4 under controlled parameters using reactors in cascade, using an excess of acid, at selected temperatures and selected added volumes of water and reaction times in each one of the reactors, in a continuous process, with efficiency of the conversion of the feed into potassium hydrogen sulfate KHSO4 of up to 95%; (FIG. 1); production of potassium sulfate K2504 (SOP) by pouring the produced potassium acid sulfate KHSO4 in a wet methanol solution at a selected vol/vol ratio for precipitation of potassium sulfate K2SO4 (SOP) under controlled temperature, ratio of wet methanol to potassium acid sulfate Date Recue/Date Received 2021-03-02 KHSO4 and reaction time; yielding a controlled acidic filtrate and byproducts such as methanol, which are recovered (FIGs. 2); production of magnesium sulfate (FIG. 3) by reacting the acid recovered from the production of potassium acid sulfate KHSO4 with calcined tailings, in wet methanol, thereby eliminating acid prior to recovery of the methanol, which in turn allows the recovery of the potassium values of entities unreacted previously (see Relations 3, 4, 5 7) in absence of cavitation, while recycling magnesium chloride MgCl2 obtained by crystallization of the magnesium sulfate MgSO4 to the production of potassium acid sulfate KHSO4 (see of FIG. 1) and recovering of potassium values from unreacted KCI and potassium acid sulfate KHSO4 (relation 11), in the filtrate of potassium sulfate K2SO4 (SOP). A direct access to sulfate of potassium and magnesium (SOPM) is obtained by reacting potassium acid sulfate KHSO4with calcined tailings and sulfuric acid (see Relation 9).
[0052] There is thus provided a process for the production of potassium sulfate K2SO4 (SOP) and sulfate of potassium and magnesium K2504 2MgSO4 (SOPM) comprising the formation of potassium acid sulfate KHSO4 from the reaction of potassium chloride with sulfuric acid followed by treatment of the potassium acid sulfate KHSO4 in methanol/water to give potassium sulfate K2SO4 (SOP) and sulfuric acid; the sulfuric acid being reacted with calcined serpentinic to obtain magnesium sulfate, which can be combined with potassium sulfate K2504 (SOP) to obtain sulfate of potassium and magnesium K2SO4 2MgSO4 (SOPM).
[0053] The potassium acid sulfate KHSO4 is prepared on a continuous basis using a succession of reactors; a first reactor, operated at about 90-100 C being used for an initial sulfatation of potash KCI with control of foaming; a second reactor, operated at about 120-125 C completing the reaction between potash KCI and sulfuric to 95%; and a third reactor being used to process the potassium acid sulfate KHSO4to target concentration and temperature.
[0054] In experiments, water was added at a constant rate to the first reactor at the level of about 11% of the initial weight of potash KCI feed; to the second reactor at the level of about 33% of the initial weight of the potash KCI feed, and in the third reactor io reach obtain a near saturated solution of potassium acid sulfate KHSO4 between about 85g/100m1 and about 95g/100m1 at a temperature in the range between about 65 and about 70 C. The hydrochloric acid may be Date Recue/Date Received 2021-03-02 collected under a slight vacuum (5-10 inches of water) and condensed at 2 C to give 35%
hydrochloric acid HCI. The contact time in the first and the second reactors were about two hours in each reactors, and about one hour in the third reactor.
hydrochloric acid HCI. The contact time in the first and the second reactors were about two hours in each reactors, and about one hour in the third reactor.
[0055] In the presently disclosed process, the potassium acid sulfate KHSO4 is contacted with a methanol /water solution to produce potassium sulfate K2SO4 (SOP) and liberate sulfuric acid in a fourth reactor. The well mixed components are kept between about 40 and about 45 C, the methanol/water in the fourth reactor being a 80/20 vol/vol mixture and the potassium acid sulfate KHSO4 a near saturated solution between about 85 and about 90g/100m1 at a temperature between about 65 and about 70 C. The volumes of potassium acid sulfate KHSO4 solution feed to 80/20 wet methanol in the fourth reactor are adjusted to maintain a ratio of between about 1.25 and about 1.75 moles of potassium acid sulfate KHSO4 per liter of wet methanol in each batch. The potassium sulfate K2504 (SOP) is filtered, rinsed with the about 80/20 wet methanol leaving a filtrate that contains water, methanol, sulfuric acid, some dissolved potassium sulfate, unreacted potassium acid sulfate KHSO4 and traces of potash KCI and NaCI from the production of potassium acid sulfate KHSO4; the acidic filtrate is neutralized with calcined serpentinic tailings by contact at a temperature in a range between about 70 and about 80 C, for example of 75 C, for about two hours in order to insure the neutrality of this mixture before the recovery of methanol by distillation; after filtration of the insolubles from the calcined serpentinic tailings and rinsing, methanol is distilled to leave a solution of magnesium sulfate with minor amounts of potassium sulfate, sodium sulfate and magnesium chloride; the solution is evaporated to give magnesium sulfate heptahydrate with some potassium sulfate in a mother liquor rich in magnesium chloride. The presence of magnesium sulphate MgSO4 and K2SO4 in the solution may be increased by adding potassium acid sulfate KHSO4, sulfuric acid H2SO4 and an additional amount of calcined tailing in order to give an increase amount of K2504 and magnesium sulphate MgSO4, in the molar ratio of about 1 to about 2 upon evaporation. The mother liquor, which is rich in MgCl2 after evaporation, is recycled to the first reactor of the production of KHSO4 in order to liberate the chlorine as hydrochloric acid HCI.
[0056] The potassium sulfate SOP is combined in selected ratio with magnesium sulfate heptahydrate and dried at about 175 C to produce sulfate of potassium and magnesium Date Recue/Date Received 2021-03-02 K2SO4 2MgSO4 (SOPM), application of pressure completing the bonding of the sulfates.
[0057] As people in the art will now be in a position to appreciate, the process of the present disclosure combines and sequences specific operational steps with selected parameters, for the production of potassium sulfate SOP and sulfate of potassium and magnesium SOPM in essentially quantitative yields while allowing adjusting the volume of potassium sulfate SOP and sulfate of potassium and magnesium SOPM produced according to predetermined targets.
[0058] The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.
Date Recue/Date Received 2021-03-02
Date Recue/Date Received 2021-03-02
Claims (24)
1. A process of production of chloride free fertilizers, comprising forming potassium acid sulfate (KHSO4) by reacting potash (KCI) with sulfuric acid (H2SO4); and one of:
i) producing potassium sulfate (SOP) by forming a water solution of the formed potassium acid sulfate (KHSO4) and mixing with wet methanol, thereby precipitating potassium sulfate (SOP); and ii) producing potassium sulfate (SOP) by forming a water solution of the formed potassium acid sulfate (KHSO4) and mixing with wet methanol, thereby precipitating potassium sulfate (SOP) and liberating sulfuric acid (H2504), reacting the sulfuric acid (H2504) with calcined serpentinic to obtain magnesium sulfate (MgSO4; and combining the magnesium sulfate (MgSO4) with the potassium sulfate (SOP) in a ratio of one potassium sulfate (SOP) for two magnesium sulfate (MgSO4), thereby yielding sulfate of potassium and magnesium (SOPM).
i) producing potassium sulfate (SOP) by forming a water solution of the formed potassium acid sulfate (KHSO4) and mixing with wet methanol, thereby precipitating potassium sulfate (SOP); and ii) producing potassium sulfate (SOP) by forming a water solution of the formed potassium acid sulfate (KHSO4) and mixing with wet methanol, thereby precipitating potassium sulfate (SOP) and liberating sulfuric acid (H2504), reacting the sulfuric acid (H2504) with calcined serpentinic to obtain magnesium sulfate (MgSO4; and combining the magnesium sulfate (MgSO4) with the potassium sulfate (SOP) in a ratio of one potassium sulfate (SOP) for two magnesium sulfate (MgSO4), thereby yielding sulfate of potassium and magnesium (SOPM).
2. The process as in Claim 1, wherein said forming the potassium acid sulfate (KHSO4) comprises initiating sulfatation of potassium chloride (KCI) with control of foaming at a temperature between about 90 and about 1000C in a first reactor; completing the sulfatation of the potassium acid sulfate (KHSO4) at a temperature between about 120 and about 125 C in a second reactor; and adjusting a concentration and a temperature of the potassium acid sulfate (KHSO4) in a third reactor.
3. The process as in Claim 2, comprising adding water to the first reactor in an amount in a range between about 9 and about 13 % of a weight of the potash (KCI); adding water to the second reactor in a range between 30 and 35 % of the weight of the potash (KCI); and adding water in the third reactor to yield a solution of potassium acid sulfate (KHSO4) between about 85g/100m1 and about 95g/100m1 of potassium acid sulfate (KHSO4) at a temperature between about 65 and about 70 C.
4. The process as in Claim 2, comprising collecting hydrochloric acid (FICI), resulting from reactions in the first and second reactors under vacuum, and condensing the collected hydrochloric acid (FICI).
5. The process as in Claim 2, wherein a contact time in the first reactor is about two hours, a contact time in the second reactor is about two hours, and a contact time in the third reactor is about one hour.
6. The process as in Claim 1, wherein the potassium acid sulfate (KHSO4) solution is contacted with a wet methanol solution to produce the potassium sulfate (SOP) and liberate the sulfuric acid (H2SO4).
7. The process as in Claim 6, comprising addition of the water solution formed of a wet methanol solution of about 80/20 vol/vol to the solution of the formed potassium acid sulfate (KHSO4) in wet methanol, the potassium acid sulfate (KHSO4) being a near saturated solution of between about 85 and about 90g/100ml at a temperature in a range between about 65 and about 70°C.
8. The process as in Claim 6, wherein said forming the potassium acid sulfate (KHSO4) comprises initiating sulfatation of potassium chloride (KCI) with control of foaming at a temperature between about 90 and about 100°C in a first reactor;
completing the sulfatation of the potassium acid sulfate (KHSO4) at a temperature between about 120 and about 125°C in a second reactor, between KCI and sulfuric to about 95%; and adjusting a concentration and a temperature of the potassium acid sulfate (KHSO4) in a third reactor; and wherein volumes of potassium acid sulfate (KHSO4) solution added to a fourth reactor containing wet methanol 80/20 vol/vol are adjusted to maintain a ratio in a range between about 1.25 and 1.75 moles of potassium acid sulfate (KHSO4) per liter of wet methanol in the fourth reactor.
completing the sulfatation of the potassium acid sulfate (KHSO4) at a temperature between about 120 and about 125°C in a second reactor, between KCI and sulfuric to about 95%; and adjusting a concentration and a temperature of the potassium acid sulfate (KHSO4) in a third reactor; and wherein volumes of potassium acid sulfate (KHSO4) solution added to a fourth reactor containing wet methanol 80/20 vol/vol are adjusted to maintain a ratio in a range between about 1.25 and 1.75 moles of potassium acid sulfate (KHSO4) per liter of wet methanol in the fourth reactor.
9. The process as in Claim 6, comprising filtering and rinsing the potassium sulfate (SOP) with a wet methanol 80/20 vol/vol, thereby obtaining a filtrate containing water, methanol, sulfuric acid, some dissolved potassium sulfate, unreacted potassium acid sulfate and traces of KCI and NaCI.
10. The process as in Claim 9, further comprising neutralizing the filtrate with calcined serpentinic tailings by contact at a temperature in a range between about 70 and about 80 C
for about two hours, and recovery of methanol by distillation.
for about two hours, and recovery of methanol by distillation.
11. The process as in Claim 10, comprising filtering insolubles from the calcined serpentinic tailings and rinsing; and said distillation of methanol yields a solution of magnesium sulfate (MgSO4) with minor amounts of potassium sulfate, sodium sulfate and magnesium chloride.
12. The process as in Claim 11, comprising evaporating a resulting solution to yield magnesium sulfate heptahydrate with some potassium sulfate and a mother liquor rich in magnesium chloride.
13. The process as in any one of Claims 10, 11 and 12, comprising increasing an amount of magnesium sulfate (MgSO4) and potassium sulfate K2504 (SOP) in solution by adding potassium acid sulfate (KHSO4), sulfuric acid (H2504) and an additional amount of calcined tailings, to give an increase of the amount of potassium sulfate K2504 (SOP) and magnesium sulfate (MgSO4), in a molar ratio between about 1 and about 2 upon evaporation.
14. The process as in any one of Claims 12 and 13, wherein a mother liquor in magnesium chloride (MgCl2), after evaporation, is recycled to the first reactor in order to liberate chlorine as HCI.
15. The process as Claim 1, wherein the potassium sulfate (SOP) is combined in selected ratio with magnesium sulfate heptahydrate and dried at about 175 C
to give sulfate of potassium and magnesium (SOPM).
to give sulfate of potassium and magnesium (SOPM).
16. The process as in any one of Claims 1 to 15, wherein said forming potassium acid sulfate (KHSO4) by reacting potash (KCI) with sulfuric acid (H2504) comprises using sulfuric acid (H2504) in excess.
17. The process as Claim 1, comprising i) producing potassium sulfate (SOP) by forming a water solution of the formed potassium acid sulfate (KHSO4) and mixing with wet methanol, thereby precipitating potassium sulfate (SOP) and liberating sulfuric acid (H2504), and reacting the sulfuric acid (H2504) with calcined serpentinic to obtain magnesium sulfate (MgSO4);
18. A system for production of chloride free fertilizers, comprising one of:
i) an array of reactors in series for a continuous production of potassium hydrogen sulfate (KHSO4) under controlled parameters by reacting potash (KCI) with sulfuric acid (H2504); and a second reactor receiving the formed potassium acid sulfate (KHSO4) and a solution of wet methanol of about 80/20 vol/vol for precipitation of potassium sulfate K2504 (SOP), thereby liberating sulfuric acid (H2504), reacting the sulfuric acid (H2504) with calcined serpentinic to obtain magnesium sulfate (MgSO4); and ii) an array of three reactors in series for a continuous production of potassium hydrogen sulfate (KHSO4) under controlled parameters by reacting potash (KCI) with sulfuric acid (H2504); a fourth reactor receiving the formed potassium acid sulfate (KHSO4) and a solution of wet methanol of about 80/20 vol/vol for precipitation of potassium sulfate K2504 (SOP), thereby liberating sulfuric acid (H2504), reacting the sulfuric acid (H2504) with calcined serpentinic to obtain magnesium sulfate (MgSO4); and a fifth reactor receiving the magnesium sulfate (MgSO4) with the potassium sulfate (SOP), for producing sulfate of potassium and magnesium (SOPM).
i) an array of reactors in series for a continuous production of potassium hydrogen sulfate (KHSO4) under controlled parameters by reacting potash (KCI) with sulfuric acid (H2504); and a second reactor receiving the formed potassium acid sulfate (KHSO4) and a solution of wet methanol of about 80/20 vol/vol for precipitation of potassium sulfate K2504 (SOP), thereby liberating sulfuric acid (H2504), reacting the sulfuric acid (H2504) with calcined serpentinic to obtain magnesium sulfate (MgSO4); and ii) an array of three reactors in series for a continuous production of potassium hydrogen sulfate (KHSO4) under controlled parameters by reacting potash (KCI) with sulfuric acid (H2504); a fourth reactor receiving the formed potassium acid sulfate (KHSO4) and a solution of wet methanol of about 80/20 vol/vol for precipitation of potassium sulfate K2504 (SOP), thereby liberating sulfuric acid (H2504), reacting the sulfuric acid (H2504) with calcined serpentinic to obtain magnesium sulfate (MgSO4); and a fifth reactor receiving the magnesium sulfate (MgSO4) with the potassium sulfate (SOP), for producing sulfate of potassium and magnesium (SOPM).
19. The system as in Claim 18, wherein said array of three reactors comprises a first reactor configured to initiate sulfatation of potassium chloride (KCI) with control of foaming at a temperature between about 90 and about 100 C; a second reactor, connected to said first reactor and configured to complete the sulfatation of the potassium acid sulfate (KHSO4) at a temperature between about 120 and about 125 C; and a third reactor, connected to said second reactor and configured to control a concentration and a temperature of the potassium acid sulfate (KHSO4).
20. The system as in Claim 18, wherein, in said array of three reactors, water is added to the first reactor in an amount in a range between about 9 and about 13 % of a weight of the potash (KCI); water is added to the second reactor in an amount in a range between 30 and 35%
of the weight of the potash (KCI); and water is added in the third reactor to yield a solution of potassium acid sulfate (KHSO4) between about 85g/100m1 and about 95g/100ml of potassium acid sulfate (KHSO4) at a temperature between about 65 and about 700C; and a contact time in the first reactor is about two hours, a contact time in the second reactor is about two hours, and a contact time in the third reactor is about one hour.
of the weight of the potash (KCI); and water is added in the third reactor to yield a solution of potassium acid sulfate (KHSO4) between about 85g/100m1 and about 95g/100ml of potassium acid sulfate (KHSO4) at a temperature between about 65 and about 700C; and a contact time in the first reactor is about two hours, a contact time in the second reactor is about two hours, and a contact time in the third reactor is about one hour.
21. The system as in Claim 18, wherein said fourth reactor contains a wet methanol solution of about 80/20 vol/vol, and the potassium acid sulfate (KHSO4) is contacted with the wet methanol solution during about one hour under good stirring to produce the potassium sulfate (SOP) and liberate the sulfuric acid (H2504).
22. The system as in any one of Claims 18 to 21, comprising a fifth reactor receiving a filtrate from said fourth reactor after precipitation of the potassium sulfate K2504 (SOP), said fifth rector being fed with calcined serpentinic tailings.
23. The system of Claim 18, comprising i) an array of reactors in series for a continuous production of potassium hydrogen sulfate (KHSO4) under controlled parameters by reacting potash (KCI) with sulfuric acid (H2504); and a second reactor receiving the formed potassium acid sulfate (KHSO4) and a solution of wet methanol of about 80/20 vol/vol for precipitation of potassium sulfate K2504 (SOP), thereby liberating sulfuric acid (H2504), reacting the sulfuric acid (H2504) with calcined serpentinic to obtain magnesium sulfate (MgSO4).
24. A process of production of chloride free fertilizers, comprising producing potassium hydrogen sulfate KHSO4 from KCI under controlled parameters using reactors in cascade, using an excess of acid, at selected temperatures and selected added volumes of water and reaction times in each one of the reactors, in a continuous process; production of potassium sulfate K2504 (SOP) by pouring the produced potassium acid sulfate KHSO4 in a wet methanol solution at a selected vol/vol ratio for precipitation of potassium sulfate K2504 (SOP) under controlled temperature, ratio of wet methanol to potassium acid sulfate KHSO4 and reaction time; yielding a controlled acidic filtrate; production of magnesium sulfate by reacting acid recovered from the production of potassium acid sulfate KHSO4 with calcined tailings, in wet methanol, thereby eliminating acid prior to recovery of methanol by distillation, allowing recovery of potassium values of entities unreacted previously, in absence of cavitation, while recycling magnesium chloride MgCl2 obtained by crystallization of magnesium sulfate MgSO4 to the production of potassium acid sulfate KHSO4 and recovering of potassium values from unreacted KCI and potassium acid sulfate KHSO4, in a filtrate of the potassium sulfate K2504 (SOP), thereby allowing a direct access to sulfate of potassium and magnesium (SOPM) by reacting potassium acid sulfate KHSO4 with calcined tailings and sulfuric acid.
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| CN117263723A (en) * | 2023-09-20 | 2023-12-22 | 天津科技大学 | Method for preparing potassium magnesium sulfate fertilizer by adding bittern into bittern from seawater and evaporating bittern |
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| CN117263723A (en) * | 2023-09-20 | 2023-12-22 | 天津科技大学 | Method for preparing potassium magnesium sulfate fertilizer by adding bittern into bittern from seawater and evaporating bittern |
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