A kind of production method of potassium magnesium sulfate fertilizer

Abstract

The invention discloses a production method of potassium sulfate and magnesium fertilizer, which comprises the following steps: placing a potassium mixed salt ore in high potassium brine under stirring conditions for conversion reaction, wherein the potassium ion content in the high potassium brine is 2.0% to 2.5%, and the magnesium ion content is 3.5% to 5.5%; after the conversion reaction is completed, adding a collecting agent to the reaction solution for flotation to obtain flotation foam and flotation slurry; filtering, drying and packaging the flotation foam to obtain the potassium sulfate and magnesium fertilizer. The production method of potassium sulfate and magnesium fertilizer of the invention uses high potassium brine as a conversion flotation medium, and by using the specific flotation medium to replace the traditional process of using fresh water and decomposition mother liquor as the conversion flotation medium, the potassium recovery rate in the potassium mixed salt ore can be significantly improved, and the specific recovery rate can be as high as 78% or more, which effectively reduces the consumption of potassium mixed salt ore in salt fields and reduces production costs.

Description

Technical Field

[0001] The invention relates to the technical field of production of potassium-magnesium sulfate fertilizer, and in particular to a production method of potassium-magnesium sulfate fertilizer. Background Art

[0002] The chemical name of potassium magnesium sulfate fertilizer is soft potassium magnesium vanadium, and its chemical formula is MgSO4K2SO4·6H2O. It is a high-quality fertilizer that provides nutrients such as potassium, magnesium, and sulfur. Its raw material is potassium mixed salt ore, which is obtained by evaporation and sun exposure from sulfate brine.

[0003] The existing production method is to use the salt field potassium mixed salt ore conversion flotation method to produce potassium sulfate magnesium fertilizer process, which mainly adopts the conversion-flotation-washing-drying process, that is, by adding fresh water, decomposing the mother liquor, and heating to 25°C, the KCl and MgSO4·7H2O in the potassium mixed salt ore are converted into soft potassium magnesium vanadium, and then sodium hexadecyl sulfonate is added as a collecting agent for flotation. The obtained crystal potassium foam is filtered and washed to obtain potassium sulfate magnesium fertilizer products. This existing process is widely used in salt lake potassium chloride production plants, and has the characteristics of simple process flow, low production cost, and high product quality; however, the potassium recovery rate in this existing process is generally around 65%, which is a low recovery rate.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a production method of potassium magnesium sulfate fertilizer. The production method uses high potassium brine as a conversion flotation medium. By replacing the traditional process of using fresh water plus decomposition mother liquor as the conversion flotation medium with the specific flotation medium, the recovery rate of potassium in potassium mixed salt ore can be significantly improved, and the specific recovery rate can be as high as more than 78%.

[0006] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0007] The present invention provides a method for producing potassium magnesium sulfate fertilizer, which comprises the following steps:

[0008] (a) placing the potassium mixed salt ore in high potassium brine under stirring conditions for conversion reaction, wherein the high potassium brine has a potassium ion content of 2.0% to 2.5% and a magnesium ion content of 3.5% to 5.5%;

[0009] (b) after the conversion reaction is completed, adding a collecting agent to the reaction solution for flotation to obtain flotation foam and flotation slurry;

[0010] (c) filtering, drying and packaging the flotation foam to obtain the potassium-magnesium sulfate fertilizer.

[0011] Preferably, the high potassium brine is prepared by the following method:

[0012] The magnesium sulfate subtype brine is first evaporated to precipitate sodium chloride, and then evaporated to precipitate magnesium sulfate, so as to obtain the high potassium brine.

[0013] Preferably, the mass ratio of the potassium mixed salt ore to the high-potassium brine is 1:(0.7-3.2).

[0014] Preferably, the conversion reaction temperature is 22-28° C., and the reaction time is 100-150 min.

[0015] Preferably, the amount of the shrinking agent added is 0.01% to 0.02% of the mass of the potassium mixed salt ore.

[0016] Preferably, the absorbent is sodium cetyl phosphate.

[0017] Preferably, the step (b) further comprises scavenging the flotation slurry to obtain scavenging liquid and scavenging foam, filtering the scavenging liquid to obtain tail solids and tail liquid, and combining the foam obtained by scavenging into the flotation foam.

[0018] Preferably, the step (c) further comprises concentrating the flotation foam before filtering.

[0019] Preferably, the concentration is to add part of the reaction liquid in the next batch of step (b) into the flotation foam and stir them to obtain a concentrated feed liquid and a concentrated foam, wherein the concentrated feed liquid is merged into the remaining reaction liquid in step (b).

[0020] Preferably, part of the reaction solution in the next batch of step (b) is added to the flotation froth to a solid-liquid ratio of 20% to 25%.

[0021] Preferably, in step (c), the filtering method is belt filtration, and the filtrate after filtration is combined with the reaction solution in the remaining step (b).

[0022] Compared with the prior art, the beneficial effects of the present invention include at least:

[0023] The production method of potassium magnesium sulfate fertilizer adopts high potassium brine as conversion flotation medium. By adopting the specific flotation medium to replace the traditional process of using fresh water and decomposition mother liquor as conversion flotation medium, the recovery rate of potassium in potassium mixed salt ore can be significantly improved, and the specific recovery rate can be as high as more than 78%, which effectively reduces the consumption of potassium mixed salt ore in salt fields and reduces production costs. DETAILED DESCRIPTION

[0024] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present invention.

[0025] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0026] Example 1

[0027] The present embodiment is a method for producing potassium magnesium sulfate fertilizer, and the method for producing potassium magnesium sulfate fertilizer comprises the following steps:

[0028] (a) Under stirring conditions, the potassium mixed salt ore is placed in the high potassium brine in a mass ratio of 1:0.7 and subjected to a conversion reaction at 22° C. for 150 minutes, wherein the high potassium brine is prepared by the following method:

[0029] The magnesium sulfate subtype brine is first evaporated to precipitate sodium chloride, and then evaporated to precipitate magnesium sulfate, so as to obtain the high potassium brine, wherein the potassium ion content of the high potassium brine is 2.0%, and the magnesium ion content is 5.5%;

[0030] (b) after the conversion reaction is completed, adding sodium cetyl phosphate to the reaction solution for flotation to obtain flotation foam and flotation slurry, wherein the amount of sodium cetyl phosphate added is 0.01% of the mass of the potassium mixed salt ore;

[0031] (c) filtering, drying and packaging the flotation foam to obtain the potassium magnesium sulfate fertilizer.

[0032] Example 2

[0033] The present embodiment is a method for producing potassium magnesium sulfate fertilizer, and the method for producing potassium magnesium sulfate fertilizer comprises the following steps:

[0034] (a) Under stirring conditions, the potassium mixed salt ore is placed in the high potassium brine in a mass ratio of 1:3.2 and subjected to a conversion reaction at 28° C. for 100 minutes, wherein the high potassium brine is prepared by the following method:

[0035] The magnesium sulfate subtype brine is first evaporated to precipitate sodium chloride, and then evaporated to precipitate magnesium sulfate, so as to obtain the high potassium brine, wherein the potassium ion content of the high potassium brine is 2.5%, and the magnesium ion content is 3.5%;

[0036] (b) after the conversion reaction is completed, adding sodium cetyl phosphate to the reaction solution for flotation to obtain flotation foam and flotation slurry, wherein the amount of sodium cetyl phosphate added is 0.02% of the mass of the potassium mixed salt ore;

[0037] (c) filtering, drying and packaging the flotation foam to obtain the potassium magnesium sulfate fertilizer.

[0038] Example 3

[0039] The present embodiment is a method for producing potassium magnesium sulfate fertilizer, and the method for producing potassium magnesium sulfate fertilizer comprises the following steps:

[0040] (a) Under stirring conditions, the potassium mixed salt ore is placed in the high potassium brine in a mass ratio of 1:2 and subjected to a conversion reaction at 25° C. for 120 min, wherein the high potassium brine is prepared by the following method:

[0041] The magnesium sulfate subtype brine is first evaporated to precipitate sodium chloride, and then evaporated to precipitate magnesium sulfate, so as to obtain the high potassium brine, wherein the potassium ion content of the high potassium brine is 2.05%, and the magnesium ion content is 4.73%;

[0042] (b) after the conversion reaction is completed, adding sodium cetyl phosphate to the reaction solution for flotation to obtain flotation foam and flotation slurry, wherein the amount of sodium cetyl phosphate added is 0.015% of the mass of the potassium mixed salt ore;

[0043] (c) filtering, drying and packaging the flotation foam to obtain the potassium magnesium sulfate fertilizer.

[0044] Example 4

[0045] The present embodiment is a method for producing potassium magnesium sulfate fertilizer, and the method for producing potassium magnesium sulfate fertilizer comprises the following steps:

[0046] (a) Under stirring conditions, the potassium mixed salt ore is placed in the high potassium brine in a mass ratio of 1:2 and subjected to a conversion reaction at 25° C. for 120 min, wherein the high potassium brine is prepared by the following method:

[0047] The magnesium sulfate subtype brine is first evaporated to precipitate sodium chloride, and then evaporated to precipitate magnesium sulfate, so as to obtain the high potassium brine, wherein the potassium ion content of the high potassium brine is 2.05%, and the magnesium ion content is 4.73%;

[0048] (b) after the conversion reaction is completed, adding sodium cetyl phosphate to the reaction solution for flotation to obtain flotation foam and flotation slurry, scavenging the flotation slurry without adding any substance to obtain scavenging liquid and scavenging foam, filtering the scavenging liquid to obtain tail solid and tail liquid, and merging the foam obtained by scavenging into the flotation foam, wherein the amount of sodium cetyl phosphate added is 0.015% of the mass of the potassium mixed salt ore;

[0049] (c) filtering, drying and packaging the flotation foam to obtain the potassium magnesium sulfate fertilizer.

[0050] Example 5

[0051] The present embodiment is a method for producing potassium magnesium sulfate fertilizer, and the method for producing potassium magnesium sulfate fertilizer comprises the following steps:

[0052] (a) Under stirring conditions, the potassium mixed salt ore is placed in the high potassium brine in a mass ratio of 1:2 and subjected to a conversion reaction at 25° C. for 120 min, wherein the high potassium brine is prepared by the following method:

[0053] The magnesium sulfate subtype brine is first evaporated to precipitate sodium chloride, and then evaporated to precipitate magnesium sulfate, so as to obtain the high potassium brine, wherein the potassium ion content of the high potassium brine is 2.05%, and the magnesium ion content is 4.73%;

[0054] (b) after the conversion reaction is completed, adding sodium cetyl phosphate to the reaction solution for flotation to obtain flotation foam and flotation slurry, scavenging the flotation slurry without adding any substance to obtain scavenging liquid and scavenging foam, filtering the scavenging liquid to obtain tail solid and tail liquid, and merging the foam obtained by scavenging into the flotation foam, wherein the amount of sodium cetyl phosphate added is 0.015% of the mass of the potassium mixed salt ore;

[0055] (c) adding part of the reaction solution of the next batch in step (b) to the flotation foam until the solid-liquid ratio is 20% to 25% and stirring to obtain a selected feed liquid and a selected foam, the selected feed liquid is combined with the remaining reaction solution in step (b), the selected foam is filtered with a belt to obtain a wet-base potassium-magnesium sulfate fertilizer and a filtrate, the filtrate is combined with the remaining reaction solution in step (b), and the wet-base potassium-magnesium sulfate fertilizer is dried and packaged to obtain the above-mentioned potassium-magnesium sulfate fertilizer.

[0056] Experimental Example 1

[0057] 1. Test equipment:

[0058] Main equipment see Table 1

[0059] Table 1 Main test equipment

[0060]

[0061] 2. Spreading agent:

[0062] Sodium cetyl phosphate (601 absorbent)

[0063] 601 Collector: Add 10g of collector to a 500ml volumetric flask to a concentration of 2% and store at room temperature for later use.

[0064] 3. Preparation and properties of test ore samples:

[0065] This test mainly uses salt field potassium mixed salt pool ore as the test ore. After sampling, the salt field potassium mixed salt ore is sent to the laboratory, and the test ore samples are mixed and reduced. The mixing process adopts the "cone transfer method", that is, the sample is repeatedly piled up with a shovel. When stacking the cone, the sample must be fed from the center of the cone so that the sample can flow from the top of the cone to the surrounding area in equal amounts. When shoveling the ore. The position of the shovel sample should be gradually shifted around the bottom of the cone. Repeat the cone stacking 5 times to mix the sample. The reduction process adopts the "quartering method" to divide the sample. After mixing and piling the sample into a cone, it is flattened into a pancake shape, and then it is divided into four parts along the center cross line with a special cross plate. Take two diagonal parts and make one part. Take samples of the original ore samples and prepare them for chemical analysis.

[0066] The properties of the test ore samples are shown in Table 2:

[0067] Table 2 Chemical analysis results of the main components of potassium mixed salt ore and high potassium brine

[0068] Sample name <![CDATA[k + ]]> <![CDATA[Na + ]]> <![CDATA[Mg 2+ ]]> <![CDATA[SO4 2- ]]> <![CDATA[Cl - ]]> proportion Potash mixed salt mine 5.5282 10.9300 6.1420 14.4193 29.1434 2.61 High Potassium Brine 2.0461 3.2532 4.7288 8.5114 14.2944 1.2967

[0069] It can be seen from Table 2 that the potassium mixed salt ore has + Content 5.2282%, potassium chloride content 10.54%, magnesium sulfate content 18.07%, magnesium chloride content 9.77%, sodium chloride content 27.79%, water content 33.84%;

[0070] 4. Test steps and analysis:

[0071] The first batch of samples and the second batch of samples were tested according to the production method in Example 5. The concentrate (i.e., flotation foam), wet-based potassium magnesium sulfate fertilizer, tailing solid, and tailing liquid after flotation were sampled and tested for K + 、Na + Mg 2+ 、SO4 2- , Cl - content, and calculate the yield and recovery rate;

[0072] Laboratory analysis:

[0073] Potassium ion sodium tetraphenylborate, chloride ion silver nitrate, sulfate ion barium chloride are determined by weighing, dissolving, and fixing the samples, and then sending them to the corresponding analytical instruments for analysis; magnesium ion is determined by ethylenediaminetetraacetic acid disodium (EDTA) aminocarboxylic acid complex titration using chrome black T as an indicator; the content of sodium ion is calculated using the law of conservation of anion and cation charge.

[0074] Analysis results:

[0075] The analysis results are shown in Table 3:

[0076] Table 3

[0077]

[0078] From Table 3, we can see that:

[0079] The present invention utilizes specific high-potassium brine to carry out conversion flotation on salt pan potassium mixed salt ore, which can completely replace fresh water conversion, and the potassium yield reaches an average of 79.19%, which is more than 10% higher than the 65% yield of fresh water plus mother liquor.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for producing potassium magnesium sulfate fertilizer, characterized in that, The steps include: (a) placing the potassium mixed salt ore in high potassium brine under stirring conditions for conversion reaction, wherein the high potassium brine has a potassium ion content of 2.0% to 2.5% and a magnesium ion content of 3.5% to 5.5%; (b) after the conversion reaction is completed, adding a collector to the reaction solution for flotation to obtain flotation foam and flotation slurry; (c) filtering, drying and packaging the flotation foam to obtain the potassium-magnesium sulfate fertilizer; The high potassium brine is prepared by the following method: The magnesium sulfate subtype brine is first evaporated to precipitate sodium chloride, and then evaporated to precipitate magnesium sulfate, so as to obtain the high potassium brine.

2. The production method according to claim 1, characterized in that The mass ratio of the potassium mixed salt ore to the high-potassium brine is 1:(0.7-3.2).

3. The production method according to claim 1, characterized in that The conversion reaction temperature is 22-28° C., and the reaction time is 100-150 min.

4. The production method according to claim 1, characterized in that The added amount of the collector is 0.01% to 0.02% of the mass of the potassium mixed salt ore.

5. The production method according to claim 1, characterized in that: The collector is sodium hexadecyl phosphate.

6. The production method according to claim 1, characterized in that: The step (b) further comprises scavenging the flotation slurry to obtain scavenging liquid and scavenging foam, filtering the scavenging liquid to obtain tail solids and tail liquid, and combining the foam obtained by scavenging into the flotation foam.

7. The production method according to claim 1, characterized in that: The step (c) also includes beneficiating the flotation foam before filtering.

8. The production method according to claim 7, characterized in that: The concentrating step is to add part of the reaction liquid in the next batch of step (b) into the flotation foam and stir them to obtain a concentrating liquid and a concentrating foam, wherein the concentrating liquid is merged into the remaining reaction liquid in step (b).

9. The production method according to claim 8, characterized in that: The step of adding a portion of the reaction solution in the next batch of step (b) to the flotation foam to a solid-liquid ratio of 20% to 25%.

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