Method for preparing potassium sulfate through double decomposition coupling reverse flotation
By performing metathesis reaction in the saturated mother liquor of potassium ammonium chloride and separating and purifying potassium sulfate with flotation method, the problems of low mother liquor accumulation and potassium oxide recovery in the existing metathesis method are solved, and high-efficiency and low-energy consumption of potassium sulfate production are achieved.
Patent Information
- Application Number
- CN202411827179.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-12
- Publication Date
- 2025-03-18
AI Technical Summary
When preparing potassium sulfate, the existing metathesis method has problems such as large accumulation of mother liquor, inability to recycle all, energy-consuming processes, serious equipment corrosion, and low potassium oxide recovery rate.
Ammonium sulfate and potassium chloride were used to metathesis reaction in the saturated mother liquor of potassium ammonium chloride, and the product was isolated in combination with the flotation method, and the secondary flotation was further performed in the saturated mother liquor of potassium chloride to purify potassium sulfate.
Continuous large-scale production of potassium sulfate under normal temperature and pressure has been achieved, the recycling rate of potassium sulfate ammonium chloride mother liquor has been improved, the potassium oxide yield is greater than 85%, and energy consumption and equipment corrosion risks have been reduced.
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of flotation, and in particular relates to a method for preparing potassium sulfate by double decomposition coupled reverse flotation. Background Art
[0002] Research status at home and abroad: The methods for producing potassium sulfate at home and abroad can be roughly divided into three categories: the first category is to extract using salt lake brine and underground brine, mainly including high temperature salt method, bittern evaporation flotation method, ion exchange method, etc.; the second category is to use natural potassium sulfate ore or potassium ore to produce; the third category is to convert sulfate-containing materials with potassium chloride to produce potassium sulfate, which is mainly divided into Mannheim method, placement method, double decomposition method, etc. These main conversion methods are summarized below:
[0003] The disadvantages of the Mannheim process are: the production capacity of a single Mannheim reactor is low, the equipment is severely corroded, the energy consumption is high, and the sale of by-product hydrochloric acid is difficult. The disadvantages of the association method are: the scale of manufacturers is small, and manufacturers have associated agent poisoning and losses during the production process. The problem is being solved. Among the double decomposition methods, the ammonium sulfate double decomposition method is a new method developed in China in recent years. It has the advantages of simple process, reaction at room temperature and pressure, and continuous operation; the disadvantage is that the mother liquor is large in volume and cannot be fully recycled, and energy-consuming processes such as evaporation concentration and cooling crystallization are required. In addition, the evaporation concentration is particularly corrosive to the equipment due to the chloride ions contained in the mother liquor, the scale is small, and the potassium oxide recovery rate is low (less than 70%). Summary of the invention
[0004] In order to solve the above technical problems, an embodiment of the present invention provides a method for preparing potassium sulfate by double decomposition coupled with reverse flotation.
[0005] To achieve the above object, the embodiments of the present invention adopt the following technical solutions:
[0006] The present invention provides a method for preparing potassium sulfate by double decomposition coupled with reverse flotation, comprising the following steps:
[0007] A. Add ammonium sulfate and potassium chloride to the saturated mother liquor of potassium sulfate and ammonium chloride for double decomposition reaction. After the reaction is completed, add a flotation agent to mix the slurry and perform primary flotation to obtain underflow solids;
[0008] B. For the bottom flow solids of the primary flotation, add saturated potassium chloride mother liquor and flotation agent to make slurry and then carry out secondary flotation. The bottom flow of the secondary flotation is potassium sulfate.
[0009] In some embodiments, in step A, the particle size of the ammonium sulfate is 0.01 to 0.25 mm, and the particle size of the potassium chloride is 0.01 to 0.25 mm;
[0010] The molar ratio of ammonium sulfate to potassium chloride is 1:2, wherein the potassium chloride includes the potassium chloride in step A and the potassium chloride contained in the saturated potassium chloride mother liquor in step B;
[0011] The temperature of the double decomposition reaction is 25° C., and the reaction time is 2.5 to 3 hours.
[0012] In some embodiments, in step A, the mass ratio of the volume of the flotation agent to the saturated potassium sulfate and ammonium chloride mother liquor is 3 mL:800 g.
[0013] In some embodiments, in step B, the mass ratio of the volume of the flotation agent to the saturated potassium chloride mother liquor is 1 mL:50 g.
[0014] In some embodiments, in step A and step B, the mass ratio of the flotation agent consisting of the collector and the frother is 6:(0.05-1).
[0015] In some embodiments, the collector comprises CF3(CF2CH2CH2CF2) q NH2, CF3 (CH2CH2CF2) n NH2, CF3 (CH2CF2) m At least one of NH2, wherein q is 3 to 5, n is 3 to 6, and m is 3 to 5, and the foaming agent is hexadecyltrimethylammonium chloride.
[0016] In some embodiments, the CF3(CF2CH2CH2CF2) q The preparation method of NH2 comprises the following steps:
[0017] The molar ratio of CF3 (CF2CH2CH2CF2) is 1:1 q ICF3(CF2CH2CH2CF2) q I and an amino source are reacted at 90°C and normal pressure for 10 hours to obtain the product;
[0018] In some embodiments, the CF3(CH2CH2CF2) n The preparation method of NH2 comprises the following steps:
[0019] CF3(CH2CH2CF2) with a molar ratio of 1:1 n NH2 and amino source react at 90℃ and normal pressure for 10h to obtain the product;
[0020] In some embodiments, the CF3(CH2CF2) m The preparation method of NH2 comprises the following steps:
[0021] CF3(CH2CF2) with a molar ratio of 1:1m OH is reacted with an amino source at 200°C and normal pressure for 10 hours to obtain the product.
[0022] In some embodiments, the amino source is ammonia gas or ammonia water.
[0023] The technical scheme adopted by the present invention is: ammonium sulfate and potassium chloride are subjected to double decomposition reaction in a saturated potassium sulfate and ammonium chloride mother liquor, after the ammonium chloride in the product is floated out and separated by a coupled flotation method, the saturated potassium chloride mother liquor is added to further purify the bottom flow potassium sulfate product (containing potassium ammonium sulfate and other substances) to obtain potassium sulfate. The method of the present invention can be continuously produced on a large scale at normal temperature and pressure, the potassium sulfate and ammonium chloride mother liquor is recycled (only used for preparation once), and the potassium oxide yield is greater than 85%. DETAILED DESCRIPTION
[0024] The technical solutions in some embodiments of the present disclosure are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments provided by the present disclosure, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present disclosure.
[0025] Example 1
[0026] Add 800g of saturated mother liquor of ammonium chloride and potassium sulfate into a glass beaker, start the stirrer, weigh 118.92g of solid ammonium sulfate and 121.07g of solid potassium chloride (the particle size of ammonium sulfate is 0.2mm, and the particle size of potassium chloride is 0.2mm), put them into the plexiglass reaction tank in the order of ammonium sulfate first and potassium chloride later, stir and mix at normal temperature and pressure, and react for 2.5h.
[0027] At the end of the reaction, 3 mL of flotation agent was added to mix the pulp for 3 minutes, and primary flotation was carried out in a flotation machine. The primary flotation obtained ammonium chloride solid (58.27 g, nitrogen content 22.77%, chlorine content 58.54%), which was filtered and dried; 50 g of potassium chloride saturated mother liquor and 1 mL of flotation agent were added to the primary flotation underflow solid, and the pulp was mixed for 5 minutes and then secondary flotation was carried out. The flotation solid obtained by the secondary flotation entered the primary flotation of the next cycle, and the underflow solid obtained by the secondary flotation (potassium sulfate product 118.7 g, potassium oxide content 44.29%, chlorine content 2.97%, zero-cycle potassium oxide yield 62.57%).
[0028] In the circulation experiment, 800 g of saturated mother liquor of ammonium chloride and potassium sulfate was added to a glass beaker, and the stirrer was started. 118.92 g of solid ammonium sulfate and 121.07 g of solid potassium chloride were weighed and put into the organic glass reaction tank in the order of ammonium sulfate first and potassium chloride later. The mixture was stirred and mixed at normal temperature and pressure, and the reaction was carried out for 2.5 h.
[0029] At the end of the reaction, the flotation solid obtained from the secondary flotation of the previous experiment was added, and then 3 mL of flotation agent was added to mix the pulp for 3 minutes, and primary flotation was carried out in a flotation machine. The primary flotation obtained solid ammonium chloride (59.80 g, nitrogen content 22.63%, chlorine content 59.80%) was filtered and dried; 50 g of potassium chloride saturated mother liquor and 1 mL of flotation agent were added to the primary flotation underflow solid, and the pulp was mixed for 5 minutes and then secondary flotation was carried out. The flotation solid obtained by the secondary flotation entered the primary flotation of the next cycle, and the underflow solid obtained by the secondary flotation (potassium sulfate product 170.03 g, potassium oxide content 43.93%, chlorine content 3.96%, cyclic experiment potassium oxide yield 88.77%).
[0030] The saturated mother liquor of ammonium chloride and potassium sulfate is prepared by adding excess potassium sulfate and ammonium chloride into deionized water and heating to 50° C. to dissolve the mixture, and standing the mixture for 12 hours. When two crystals are precipitated, the mixture is saturated.
[0031] The saturated mother liquor of potassium chloride is prepared by adding excess potassium chloride to deionized water and heating to 50° C. to dissolve the mixture, leaving the mixture to stand for 12 hours. When crystals precipitate, the mixture is saturated. 50 g of the saturated mother liquor of potassium chloride contains 13.12 g of potassium chloride (25° C.).
[0032] Preparation of the flotation agent: 6g CF3 (CF2CH2CH2CF2) q NH2 (q=5), 0.1 g hexadecyltrimethylammonium chloride and 100 mL deionized water are heated to 50°C and dissolved to obtain a flotation agent.
[0033] CF3(CF2CH2CH2CF2) q Preparation method of NH2(q=5):
[0034] The product is obtained by reacting 10.562g of CF3(CF2CH2CH2CF2)5I with aqueous ammonia containing 0.34062g of NH3 at 90°C and normal pressure for 10h.
[0035] Example 2
[0036] Add 800g of saturated mother liquor of ammonium chloride and potassium sulfate into a glass beaker, start the stirrer, weigh 118.92g of solid ammonium sulfate and 121.07g of solid potassium chloride (the particle size of ammonium sulfate is 0.25mm, and the particle size of potassium chloride is 0.25mm), put them into the plexiglass reaction tank in the order of ammonium sulfate first and potassium chloride later, stir and mix at normal temperature and pressure, and react for 2.5h.
[0037] At the end of the reaction, 3 mL of flotation agent was added to mix the pulp for 3 minutes, and primary flotation was carried out in a flotation machine. The primary flotation obtained ammonium chloride solid (77.74 g, nitrogen content 24.08%, chlorine content 53.23%), which was filtered and dried; 50 g of potassium chloride saturated mother liquor and 1 mL of flotation agent were added to the primary flotation underflow solid, and the pulp was mixed for 5 minutes and then secondary flotation was carried out. The flotation solid obtained by the secondary flotation entered the primary flotation of the next cycle, and the underflow solid obtained by the secondary flotation (potassium sulfate product 126.86 g, potassium oxide content 42.35%, chlorine content 2.97%, zero-cycle potassium oxide yield 76.35%).
[0038] In the circulation experiment, 800 g of saturated mother liquor of ammonium chloride and potassium sulfate was added to a glass beaker, and the stirrer was started. 118.92 g of solid ammonium sulfate and 121.07 g of solid potassium chloride were weighed and put into the organic glass reaction tank in the order of ammonium sulfate first and potassium chloride later. The mixture was stirred and mixed at normal temperature and pressure, and the reaction was carried out for 3 hours.
[0039] At the end of the reaction, the flotation solid obtained from the secondary flotation of the previous experiment was added, and then 3 mL of flotation agent was added to mix the pulp for 3 minutes, and primary flotation was carried out in a flotation machine. The primary flotation obtained solid ammonium chloride (68.07 g, nitrogen content 23.02%, chlorine content 55.87%) was filtered and dried; 50 g of potassium chloride saturated mother liquor and 1 mL of flotation agent were added to the primary flotation underflow solid, and the pulp was mixed for 5 minutes and then secondary flotation was carried out. The flotation solid obtained by the secondary flotation entered the primary flotation of the next cycle, and the underflow solid obtained by the secondary flotation (potassium sulfate product 165.98 g, potassium oxide content 44.03%, chlorine content 3.13%, cyclic experiment potassium oxide yield 86.85%).
[0040] The saturated mother liquor of ammonium chloride and potassium sulfate is prepared by adding excess potassium sulfate and ammonium chloride into deionized water and heating to 50° C. to dissolve the mixture, and standing the mixture for 12 hours. When two crystals are precipitated, the mixture is saturated.
[0041] The saturated mother liquor of potassium chloride is prepared by adding excess potassium chloride to deionized water and heating to 50° C. to dissolve the mixture, leaving the mixture to stand for 12 hours. When crystals precipitate, the mixture is saturated. 50 g of the saturated mother liquor of potassium chloride contains 13.12 g of potassium chloride (25° C.).
[0042] Preparation of the flotation agent: 6g CF3(CH2CH2CF2) n NH2 (n=6), 0.1g hexadecyltrimethylammonium chloride and 100mL deionized water, heat and dissolve to obtain.
[0043] CF3(CH2CH2CF2) n Preparation method of NH2(n=6):
[0044] The product is obtained by reacting 7.52292g of CF3(CH2CH2CF2)6I with aqueous ammonia containing 0.34062g of NH3 at 90°C and normal pressure for 10 hours.
[0045] Example 3
[0046] Add 800g of saturated mother liquor of ammonium chloride and potassium sulfate into a glass beaker, start the stirrer, weigh 118.92g of solid ammonium sulfate and 121.07g of solid potassium chloride (the particle size of ammonium sulfate is 0.1mm, and the particle size of potassium chloride is 0.1mm), put them into the plexiglass reaction tank in the order of ammonium sulfate first and potassium chloride later, stir and mix at normal temperature and pressure, and react for 3h.
[0047] At the end of the reaction, 3 mL of flotation agent was added to mix the pulp for 3 minutes, and primary flotation was carried out in a flotation machine. The primary flotation obtained ammonium chloride solid (72.30 g, nitrogen content 23.47%, chlorine content 50.72%), which was filtered and dried; 50 g of potassium chloride saturated mother liquor and 1 mL of flotation agent were added to the primary flotation underflow solid, and the pulp was mixed for 5 minutes and then secondary flotation was carried out. The flotation solid obtained by the secondary flotation entered the primary flotation of the next cycle, and the underflow solid obtained by the secondary flotation (potassium sulfate product 115.49 g, potassium oxide content 45.06%, chlorine content 3.69%, zero-cycle potassium oxide yield 61.85%).
[0048] In the circulation experiment, 800 g of saturated mother liquor of ammonium chloride and potassium sulfate was added to a glass beaker, and the stirrer was started. 118.92 g of solid ammonium sulfate and 121.07 g of solid potassium chloride were weighed and put into the organic glass reaction tank in the order of ammonium sulfate first and potassium chloride later. The mixture was stirred and mixed at normal temperature and pressure, and the reaction was carried out for 2.5 to 3 hours.
[0049] At the end of the reaction, the flotation solid obtained from the secondary flotation of the previous experiment was added, and then 3 mL of flotation agent was added to mix the pulp for 3 minutes, and primary flotation was carried out in a flotation machine. The primary flotation obtained ammonium chloride solid (69.97 g, nitrogen content 23.54%, chlorine content 57.64%) was filtered and dried; 50 g of potassium chloride saturated mother liquor and 1 mL of flotation agent were added to the primary flotation underflow solid, and the pulp was mixed for 5 minutes and then secondary flotation was carried out. The flotation solid obtained by the secondary flotation entered the primary flotation of the next cycle, and the underflow solid obtained by the secondary flotation (potassium sulfate product 165.86 g, potassium oxide content 44.06%, chlorine content 4.05%, cyclic experiment potassium oxide yield 86.85%).
[0050] The saturated mother liquor of ammonium chloride and potassium sulfate is prepared by adding excess potassium sulfate and ammonium chloride into deionized water and heating to 50° C. to dissolve the mixture, and standing the mixture for 12 hours. When two crystals are precipitated, the mixture is saturated.
[0051] The saturated mother liquor of potassium chloride is prepared by adding excess potassium chloride to deionized water and heating to 50° C. to dissolve the mixture, leaving the mixture to stand for 12 hours. When crystals precipitate, the mixture is saturated. 50 g of the saturated mother liquor of potassium chloride contains 13.12 g of potassium chloride (25° C.).
[0052] Preparation of the flotation agent: 6g CF3(CH2CF2) m NH2 (m=5), 0.1g hexadecyltrimethylammonium chloride and 100mL deionized water, heat to 50℃ to dissolve, and obtain.
[0053] CF3(CH2CF2) m Preparation method of NH2(m=5):
[0054] 8.648g CF3(CH2CF2)5OH and aqueous ammonia containing 0.68124g NH3 are reacted at 200℃ and normal pressure for 10h to obtain the product.
[0055] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.
[0056] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.
Claims
1. A method for preparing potassium sulfate by double decomposition coupled with reverse flotation, characterized in that: The following steps are involved: A. Add ammonium sulfate and potassium chloride to the saturated mother liquor of potassium sulfate and ammonium chloride for double decomposition reaction. After the reaction is completed, add a flotation agent to mix the slurry and perform primary flotation to obtain underflow solids; B. For the bottom flow solids of the primary flotation, add saturated potassium chloride mother liquor and flotation agent to make slurry and then carry out secondary flotation. The bottom flow of the secondary flotation is potassium sulfate.
2. The method according to claim 1, characterized in that In step A, the particle size of the ammonium sulfate is 0.01-0.25 mm, and the particle size of the potassium chloride is 0.01-0.25 mm; The molar ratio of ammonium sulfate to potassium chloride is 1:2, wherein the potassium chloride includes the potassium chloride in step A and the potassium chloride contained in the saturated potassium chloride mother liquor in step B; The temperature of the double decomposition reaction is 25° C. and the reaction time is 2.5 to 3 hours.
3. The method according to claim 1, characterized in that In step A, the mass ratio of the volume of the flotation agent to the saturated potassium sulfate and ammonium chloride mother liquor is 3 mL:800 g.
4. The method according to claim 1, characterized in that: In step B, the mass ratio of the volume of the flotation agent to the saturated potassium chloride mother liquor is 1 mL:50 g.
5. The method according to claim 1, characterized in that In step A and step B, the mass ratio of the flotation agent consisting of the collector and the frother is 6:(0.05-1).
6. The method according to claim 5, characterized in that The collector includes CF3(CF2CH2CH2CF2) q NH2, CF3 (CH2CH2CF2) n NH2, CF3 (CH2CF2) m At least one of NH2, wherein q is 3-5, n is 3-6, and m is 3-5, and the foaming agent is hexadecyltrimethylammonium chloride.
7. The method according to claim 6, characterized in that The CF3 (CF2CH2CH2CF2) q The preparation method of NH2 comprises the following steps: The molar ratio of CF3 (CF2CH2CH2CF2) is 1:1 q ICF3(CF2CH2CH2CF2) q I and an amino source are reacted at 90°C and normal pressure for 10 hours to obtain the product.
8. The method according to claim 6, characterized in that The CF3(CH2CH2CF2) n The preparation method of NH2 comprises the following steps: CF3(CH2CH2CF2) with a molar ratio of 1:1 n NH2 and an amino source are reacted at 90°C and normal pressure for 10 hours to obtain the product.
9. The method according to claim 6, characterized in that The CF3(CH2CF2) m The method for preparing NH2 comprises the following steps: CF3(CH2CF2) with a molar ratio of 1:1 m OH is reacted with an amino source at 200°C and normal pressure for 10 hours to obtain the product.
10. The method according to any one of claims 7 to 9, characterized in that: The amino source is ammonia gas or ammonia water.