Method for improving sodium chloride flotation efficiency in reverse flotation process of potash fertilizer production

Abstract

The invention discloses a method for improving sodium chloride flotation efficiency in the reverse flotation process of potash fertilizer production. The method comprises the following steps: screening sodium-containing carnallite to obtain a first product and a second product; wherein the first product is an oversize product, the mass ratio of the first product to the sodium-containing carnallite is smaller than 5%, the content of NaCl in the undersize product is larger than 65 wt%, and the content of KCl in the undersize product is smaller than 5 wt%; and carrying out thickening and flotation treatment on the first product to prepare the low-sodium carnallite, wherein a flotation agent adopted in the flotation treatment comprises a flotation agent composition, and the flotation agent composition comprises dodecyl morpholine and an additive. By adopting a specific screening process and a special flotation reagent composition, the reverse flotation efficiency is improved while the content of fine-grained sodium chloride in the carnallite is reduced, so that the content of the fine-grained sodium chloride in the low-sodium carnallite is reduced, and the quality of potassium chloride is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic chemical industry, and in particular relates to a method for improving the flotation efficiency of sodium chloride in the reverse flotation process of potash fertilizer production. Background Art

[0002] As an important chemical product, potassium chloride has important applications in agriculture, food and medicine, especially as potash fertilizer, it plays a very important role in the agricultural field. Carnallite (KC1·MgC12·6H2O), as the main raw material for the production of potassium chloride, is mainly found in salt lakes in Qinghai, Tibet and other places in my country. In Qinghai, carnallite is used as raw material and the "reverse flotation-cold crystallization" and "cold crystallization-positive flotation" processes have been adopted to achieve an annual production capacity of about 6 million tons. During the formation of carnallite in salt fields, sodium chloride will precipitate in solid form and mix with carnallite ore. The grade of carnallite ore decreases with continuous mining, and the proportion of fine-grained sodium chloride increases accordingly.

[0003] "Reverse flotation-cold crystallization" is one of the main processes for producing potassium chloride. First, the sodium-containing carnallite obtained by evaporation of salt fields is transported to the thickener by water mining. The solid content in the thickener is controlled between 20% and 30%. The thickened and adjusted materials are transported to the flotation agent for flotation to remove the sodium chloride. At present, the reverse flotation agent used in the salt lake area is mainly dodecylmorpholine. The low-sodium carnallite obtained after flotation is decomposed and crystallized to obtain a mixture of potassium chloride and sodium chloride, and further washed, filtered and other processes to prepare the potassium chloride product. Among them, the flotation effect of the carnallite flotation process on sodium chloride determines the content of sodium chloride in the low-sodium carnallite, and its content has an important influence on the decomposition and crystallization process and the main content of the potassium chloride product prepared in the back end. If the flotation effect is not good, it will lead to a high sodium chloride content in the low-sodium carnallite, and the grade of the potassium chloride prepared subsequently will be reduced accordingly. At present, the thickener can effectively increase the concentration of the sodium-containing carnallite solid phase in the material, but the removal effect on fine-grained sodium chloride is limited, resulting in a high proportion of fine-grained sodium chloride in the sodium-containing carnallite; the reverse flotation process uses a single dodecylmorpholine as a flotation agent. Dodecylmorpholine has a good flotation effect on sodium chloride crystals with larger grains, but a poor flotation effect on fine-grained sodium chloride, resulting in the inability to effectively remove the fine-grained sodium chloride in the sodium-containing carnallite through flotation, resulting in a high content of fine-grained sodium chloride in the low-sodium carnallite, which ultimately has an adverse effect on the quality of the potassium chloride product. Therefore, the flotation effect of sodium chloride in the flotation process has an important impact on the quality of the subsequent potassium chloride product. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for improving the flotation efficiency of sodium chloride in the reverse flotation process of potash fertilizer production, so as to overcome the shortcomings of the prior art.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0006] An embodiment of the present invention provides a method for improving the flotation efficiency of sodium chloride in a reverse flotation process of potash fertilizer production, which comprises:

[0007] Screening the sodium-containing carnallite to obtain a first product and a second product; wherein the first product is an oversize product, the mass ratio of the first product to the sodium-containing carnallite is less than 5%, and the content of NaCl in the undersize product is greater than 65wt%, and the content of KCl is less than 5wt%;

[0008] And, the first product is subjected to concentration and flotation treatment to obtain low-sodium carnallite; wherein the flotation agent used in the flotation treatment includes a flotation agent composition, and the flotation agent composition includes dodecylmorpholine and additives.

[0009] In some more specific embodiments, the additive includes hexadecylamine and / or sodium hexadecyl sulfonate, but is not limited thereto.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] (1) The present invention can significantly reduce the content of fine-grained ore by performing a specific screening process before the thickener to remove part of the fine-grained ore with a high sodium chloride content and a low potassium chloride content;

[0012] (2) The present invention adopts a special flotation agent composition to greatly improve the flotation effect of fine-grained sodium chloride, thereby reducing the sodium chloride content in low-sodium carnallite and further improving the quality of potassium chloride. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0014] Figure 1 The present invention is a schematic flow diagram of a method for improving the flotation efficiency of sodium chloride in a reverse flotation process of potash fertilizer production in a typical embodiment of the present invention. DETAILED DESCRIPTION

[0015] In view of the defects of the prior art, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. It is mainly aimed at the thickening and reverse flotation processes. By adding screens and adding additives to the reverse flotation agents, it provides a process solution for improving the sodium chloride removal efficiency, reducing the influence of fine sodium chloride on the decomposition and crystallization process, and improving the quality of potassium chloride.

[0016] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Specifically, as one aspect of the technical solution of the present invention, a method for improving the flotation efficiency of sodium chloride in a reverse flotation process of potash fertilizer production involves:

[0018] The sodium-containing carnallite is subjected to sieving treatment to obtain a first product (corresponding to an oversize product) and a second product (corresponding to an undersize product); wherein the first product is an oversize product, the mass ratio of the first product to the sodium-containing carnallite is less than 5%, and the content of NaCl in the undersize product is greater than 65wt%, and the content of KCl is less than 5wt%;

[0019] And, the first product is subjected to concentration and flotation treatment to obtain low-sodium carnallite; wherein the flotation agent used in the flotation treatment includes a flotation agent composition, and the flotation agent composition includes dodecylmorpholine and additives.

[0020] In some preferred embodiments, the additive includes hexadecylamine and / or sodium hexadecyl sulfonate, but is not limited thereto.

[0021] In the present invention, dodecylmorpholine is a flotation machine that has a good flotation effect on sodium chloride crystals with larger particle sizes, but has a poor flotation effect on sodium chloride crystals with smaller particle sizes. In addition to having a surfactant effect, hexadecylamine and sodium hexadecylsulfonate can also be used as emulsifiers to regulate the size of bubbles during the flotation process, so that the generated bubble particle size is smaller and more stable. Smaller bubbles can increase the collision probability between bubbles and crystals, and improve the adhesion stability of bubbles, thereby improving the flotation effect of fine-grained sodium chloride. By combining dodecylmorpholine with additives, the flotation effect of fine-grained sodium chloride in carnallite ore can be effectively improved.

[0022] Furthermore, the flotation reagent composition comprises the following components calculated by mass percentage: 80-95% dodecylmorpholine and 5-20% hexadecylamine.

[0023] Furthermore, the flotation reagent composition comprises the following components calculated by mass percentage: 80-95% dodecyl morpholine and 5-20% sodium hexadecyl sulfonate.

[0024] Furthermore, the flotation reagent composition comprises the following components calculated by mass percentage: 80-90% dodecylmorpholine, 5v10% hexadecylamine and 5-10% sodium hexadecylsulfonate.

[0025] Furthermore, the flotation reagent composition comprises a hexadecylamine aqueous solution with a concentration of 1 to 5 wt%.

[0026] Furthermore, the flotation reagent composition includes a sodium hexadecyl sulfate aqueous solution with a concentration of 1 to 10 wt%.

[0027] In some preferred embodiments, the sieving process uses a sieve with a mesh size of 100 to 140 meshes.

[0028] Furthermore, the mesh size of the sieve used in the screening process is selected from any one of 100 mesh, 120 mesh, and 140 mesh.

[0029] In some preferred embodiments, the method has a flotation efficiency of 65-75% for fine-grained sodium chloride.

[0030] In the present invention, fine-grained sodium chloride refers to sodium chloride crystals with a particle size of less than 100 mesh (particle size less than 0.15 mm).

[0031] In some preferred embodiments, the method specifically includes: placing the oversize product in a thickener for thickening treatment while controlling the solid phase concentration of the oversize product to be 25-30wt%, and then placing the obtained product and the flotation agent composition in a flotation device for flotation treatment.

[0032] In some preferred embodiments, the sodium chloride content in the sodium-containing carnallite is 15-23 wt %, wherein the mass percentage of sodium chloride in 100 mesh is 35-60 wt % of the total sodium chloride.

[0033] In some preferred embodiments, the content of sodium chloride in the low-sodium carnallite is 4-6 wt %.

[0034] In some preferred embodiments, the method further comprises: obtaining sodium-containing carnallite from a salt pan by water mining.

[0035] In some preferred embodiments, the undersize product is directly used in the tailings salt pile.

[0036] In some preferred embodiments, the low-sodium carnallite is used to produce potash fertilizer.

[0037] In some more specific embodiments, the method for improving the flotation efficiency of sodium chloride in the reverse flotation process of potash fertilizer production comprises the following steps (the flow diagram is shown in Figure 1 ):

[0038] (1) Sodium carnallite is collected from salt pans by water mining.

[0039] (2) the sodium-containing carnallite collected in step (1) is first sieved through a sieve, wherein the mesh number of the sieve is one of 100 mesh, 120 mesh or 140 mesh;

[0040] (3) The selection of the mesh size of the sieve in step (2) is based on the following criteria: (1) the mass percentage of the undersize is less than 5%, the NaCl content in the undersize is greater than 65% and the KCl content is less than 5%;

[0041] (4) The screened material after screening in step (2) enters a thickener to control the solid phase concentration of sodium carnallite at 25-30%, and the screened material directly enters the tailings pile;

[0042] (5) The concentrated material in step (4) enters a flotation machine, and after adding a flotation reagent composition, sodium chloride is removed to obtain low-sodium carnallite.

[0043] Preferably, the flotation reagent composition in step (5) is a combination of dodecylmorpholine, hexadecylamine and sodium hexadecylsulfonate, and the combination form is dodecylmorpholine+hexadecylamine, dodecylmorpholine+sodium hexadecylsulfonate or dodecylmorpholine+hexadecylamine+sodium hexadecylsulfonate.

[0044] Preferably, the mass fractions of the combination of the agents in step (6) are as follows: ① dodecylmorpholine: hexadecylamine = 80% to 95%: 20% to 5%; ② dodecylmorpholine + sodium hexadecylsulfonate = 80% to 95%: 20% to 5%; ③ dodecylmorpholine + hexadecylamine + sodium hexadecylsulfonate = 80% to 90%: 10% to 5%: 10% to 5%.

[0045] Preferably, the hexadecylamine involved in step (6) is prepared into a solution with a concentration of 1% to 5% using deionized water; and the sodium hexadecyl sulfate is prepared into a solution with a concentration of 1% to 10%.

[0046] Preferably, the low-sodium carnallite after flotation in step (5) is used in the next production process.

[0047] The invention adopts a specific screening process and a special flotation reagent composition, thereby reducing the content of fine-grained sodium chloride in carnallites and improving the reverse flotation efficiency, thereby reducing the content of fine-grained sodium chloride in low-sodium carnallites and improving the quality of potassium chloride.

[0048] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and drawings. This embodiment is implemented on the premise of the technical solution of the invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0049] Unless otherwise specified, the experimental materials used in the following examples can be purchased from conventional biochemical reagent companies.

[0050] Comparative Example 1

[0051] Using a saturated mother liquor with the following mass concentrations: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%, 225g of 200-mesh sodium chloride, 525g of saturated mother liquor, and 16μL of dodecylmorpholine were added to a 0.5L flotation cell. The roughing time was 10min. The total mass of sodium chloride floated was 1.45g, and the flotation efficiency of fine-grained sodium chloride was 0.64%.

[0052] Example 1

[0053] Using a saturated mother liquor with the following mass concentrations: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%, 225g of 200-mesh sodium chloride, 525g of saturated mother liquor, 16μL of dodecylmorpholine, and 4μL of 1w% hexadecylamine solution were added to a 0.5L flotation cell. The roughing time was 10min, and the total mass of sodium chloride floated was 56.1g. The flotation efficiency of fine-grained sodium chloride was 24.93%.

[0054] Example 2

[0055] Using a saturated mother liquor with the following mass concentrations: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%, 225g of sodium chloride with a mesh size of 200, 525g of saturated mother liquor, 17μL of dodecylmorpholine, and 3μL of a 3w% sodium hexadecylsulfonate solution were added to a 0.5L flotation cell. The roughing time was 10min, and the total mass of sodium chloride floated was 85.2g. The flotation efficiency of fine-grained sodium chloride was 37.87%.

[0056] Example 3

[0057] Using a saturated mother liquor with the following concentrations: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%, 225g of sodium chloride with a mesh size of 200, 525g of saturated mother liquor, 16μL of dodecylmorpholine, 2μL of a 3w% sodium hexadecylsulfonate solution, and 1μL of a 3w% sodium hexadecylsulfonate solution were added to a 0.5L flotation tank. The roughing time was 10min, the total mass of sodium chloride floated was 140.7g, and the flotation efficiency of fine-grained sodium chloride was 60.93%.

[0058] Example 4

[0059] The sodium carnallite composition is: KCl: 18.51%, NaCl: 16.91%, MgCl2: 28.75%. After screening with a 140-mesh screen, the weight of the undersize is 3.47%, the undersize KCl: 4.78%, NaCl: 65.88%, and the saturated mother liquor with the following concentrations is used: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%. Add 225g of the oversize, 525g of the saturated mother liquor, 16μL of dodecyl morpholine, and 4μL of 1w% hexadecylamine solution in a 0.5L flotation tank. After flotation, the low-sodium carnallite composition is: MgCl2: 34.76%; KCl: 25.24%; NaCl: 5.18%. The flotation efficiency of fine-grained sodium chloride is 65.52%.

[0060] Comparative Example 2 (without screening)

[0061] The composition of sodium carnallite is: KCl: 18.51%, NaCl.16.91%, MgCl2.28.75%, using the following concentration of saturated mother liquor: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%, adding 225g of solid ore, 525g of saturated mother liquor, and 16μL of dodecyl morpholine in a 0.5L flotation tank, the composition of low sodium carnallite after flotation is: MgCl2: 32.71%; KCl: 23.75%; NaCl: 8.16%. The flotation efficiency of fine sodium chloride is 56.32%.

[0062] Comparative Example 3 (without screening)

[0063] The sodium carnallite composition is: KCl: 18.51%, NaCl: 16.91%, MgCl2: 28.75%, using the following concentration of saturated mother liquor: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%, adding 225g of solid ore, 525g of saturated mother liquor, 16μL of dodecyl morpholine, and 4μL of 1w% hexadecylamine solution in a 0.5L flotation tank, the low sodium carnallite composition after flotation is: MgCl2: 33.51%; KCl: 24.31%; NaCl: 6.47%. The flotation efficiency of fine sodium chloride is 57.62%.

[0064] Comparative Example 4

[0065] The sodium carnallite composition is: KCl: 18.51%, NaCl: 16.91%, MgCl2: 28.75%. After screening with an 80-mesh screen, the weight of the undersize is 10.15%, the undersize KCl: 7.35%, NaCl: 59.73%, and the saturated mother liquor with the following concentrations: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%. Add 225g of the oversize, 525g of the saturated mother liquor, 16μL of dodecyl morpholine, and 4μL of 1w% hexadecylamine solution in a 0.5L flotation tank. After flotation, the low-sodium carnallite composition is: MgCl2: 35.46%; KCl: 25.63%; NaCl: 3.87%. The flotation efficiency of fine sodium chloride is 60.47%.

[0066] Comparative Example 5

[0067] The sodium carnallite composition is: KCl: 18.51%, NaCl: 16.91%, MgCl2: 28.75%. After screening with a 200-mesh screen, the weight of the undersize is 1.95%, the undersize KCl: 3.12%, NaCl: 65.87%, and the saturated mother liquor with the following concentrations: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%. Add 225g of the oversize, 525g of the saturated mother liquor, 16μL of dodecyl morpholine, and 4μL of 1w% hexadecylamine solution in a 0.5L flotation tank. After flotation, the low-sodium carnallite composition is: MgCl2: 34.51%; KCl: 24.92%; NaCl: 6.83%. The flotation efficiency of fine sodium chloride is 54.08%.

[0068] Example 5

[0069] The sodium carnallite composition is: KCl: 18.51%, NaCl: 16.91%, MgCl2: 28.75%. After screening with a 140-mesh screen, the weight of the undersize is 3.47%, the undersize KCl: 4.78%, NaCl: 65.88%, and the saturated mother liquor with the following concentrations is used: MgCl2: 31.65%; KCl: 0.57%; NaCl: 0.31%. Add 225g of the oversize, 525g of the saturated mother liquor, 16μL of dodecyl morpholine, 2μL of 1w% hexadecylamine solution and 2μL of 1w% sodium hexadecyl sulfonate solution in a 0.5L flotation tank. After flotation, the low-sodium carnallite composition is: MgCl2: 34.18%; KCl: 24.87%; NaCl: 5.36%. The flotation efficiency of fine sodium chloride is 67.74%.

[0070] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0071] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical deformation made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the protection scope of the present invention.

Claims

1. A method for improving the flotation efficiency of sodium chloride in the reverse flotation process of potash fertilizer production, characterized in that: include: Screening the sodium-containing carnallite to obtain a first product and a second product; wherein the first product is an oversize product, the mass ratio of the first product to the sodium-containing carnallite is less than 5%, and the content of NaCl in the undersize product is greater than 65wt%, and the content of KCl is less than 5wt%; And, the first product is subjected to concentration and flotation treatment to obtain low-sodium carnallite; wherein the flotation agent used in the flotation treatment includes a flotation agent composition, and the flotation agent composition includes dodecylmorpholine and additives.

2. The method according to claim 1, characterized in that: The additives include hexadecylamine and / or sodium hexadecyl sulfonate.

3. The method according to claim 2, characterized in that: The flotation reagent composition comprises the following components calculated by mass percentage: 80-95% dodecylmorpholine and 5-20% hexadecylamine; And / or, the flotation reagent composition comprises the following components calculated by mass percentage: 80-95% dodecyl morpholine and 5-20% sodium hexadecyl sulfonate; And / or, the flotation reagent composition comprises the following components calculated by mass percentage: 80-90% dodecylmorpholine, 5-10% hexadecylamine and 5-10% sodium hexadecylsulfonate.

4. The method according to claim 3, characterized in that: The flotation reagent composition comprises a hexadecylamine aqueous solution with a concentration of 1 to 5 wt%; And / or, the flotation reagent composition comprises an aqueous solution of sodium hexadecyl sulfate with a concentration of 1 to 10 wt%.

5. The method according to claim 1, characterized in that: The mesh number of the sieve used in the sieving process is 100-140 meshes, preferably any one of 100 meshes, 120 meshes and 140 meshes.

6. The method according to claim 1, characterized in that: The flotation efficiency of the method for fine-grained sodium chloride is 65-75%.

7. The method according to claim 1, characterized in that Specifically include: The product on the screen is placed in a thickener for thickening treatment while controlling the solid phase concentration of the product on the screen to be 25-30wt%, and then the obtained product and the flotation agent composition are placed in a flotation device for flotation treatment.

8. The method according to claim 1, characterized in that: The sodium chloride content in the sodium-containing carnallite is 15-23wt%, wherein the mass percentage of sodium chloride in the total sodium chloride under 100 mesh is 35-60%; And / or, the content of sodium chloride in the low-sodium carnallite is 4-6wt%.

9. The method according to claim 1, characterized in that: Also includes: Sodium carnallite is obtained from salt pans by water mining.

10. The method according to claim 1, characterized in that: The undersize product is directly used in the tailings salt pile; And / or, the low-sodium carnallite is used to produce potash fertilizer.

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