Method for regulating and controlling surface morphology of picromerite and application of picromerite in flotation of picromerite

Abstract

The invention relates to a picromerite surface topography regulation and control method and application of the picromerite surface topography regulation and control method in picromerite flotation. The picromerite particles are added into a solution for ultrasonic pretreatment, so that a large number of cracks and pits are generated on the surfaces of the picromerite particles, and the specific surface area and adsorption sites of the picromerite particles are increased; and then mixing the picromerite particles subjected to ultrasonic pretreatment with a saturated picromerite solution and a collecting agent for flotation, filtering flotation concentrate, and fully drying to obtain picromerite with higher purity. According to the method, the recovery rate of picromerite can be remarkably increased under the conditions that original flotation equipment is not changed and the variety and number of collecting agents are not increased, and therefore the method has important significance in the aspects of comprehensive utilization of sylvite resources, green flotation process popularization, improvement of the self-sufficiency rate of potash fertilizer in China and the like.

Description

Technical Field

[0001] The present invention relates to the field of mineral processing and chemical technology, and in particular to a method for controlling the surface morphology of leonite and an application thereof in leonite flotation. Background Art

[0002] Potassium fertilizer is an essential fertilizer in agricultural production and plays a vital role in plant growth and development. Global demand for potassium fertilizer continues to grow, and its production is crucial for food security and sustainable agricultural development. Kabeinite (MgSO4·K2SO4·6H2O) is an important raw material for synthetic potassium fertilizer and is primarily obtained through flotation. However, the recovery rate of kabeinite in actual mineral flotation is low. This is primarily due to its high water solubility and poor surface hydrophobicity, which results in weak interaction between kabeinite and traditional collectors (such as sodium dodecyl sulfate). This not only affects flotation efficiency but also severely restricts resource utilization.

[0003] Current strategies for improving the flotation recovery rate of soft potassium magnesium alum include: (1) developing new collectors to enhance the interaction between the collector and the mineral, such as Chinese patent CN115888990B, which proposes a composite collector for the flotation of soft potassium magnesium alum with stronger adsorption selectivity and collection capacity; and (2) optimizing flotation parameters, such as stirring rate and reagent addition amount. Although these methods have some effects, they generally have problems such as high cost, high environmental risks, and poor technical adaptability, making it difficult to fundamentally improve the floatability of soft potassium magnesium alum. Summary of the Invention

[0004] This invention introduces ultrasonic technology into the flotation process of leonite. Ultrasonic pretreatment modifies the surface morphology and active site distribution of leonite particles, thereby enhancing collector adsorption and bubble adhesion. This method not only overcomes the technical bottleneck of traditional processes for the recovery of highly water-soluble minerals, but also significantly improves the recovery rate of leonite, demonstrating strong industrial application value.

[0005] In order to achieve the above object, the present invention provides a method for controlling the surface morphology of leonite, comprising: adding leonite particles to a saturated leonite solution, then ultrasonically treating the mixture, and finally filtering to obtain leonite with cracks and depressions on the surface.

[0006] In the above scheme, the particle size of the soft potassium magnesium sulfate particles is controlled between 0.074-0.15 mm.

[0007] In the above scheme, the saturated leonite solution is prepared as follows: an excess of leonite is mixed with water and stirred thoroughly. When the mass of solids in the solution no longer decreases, the solution is filtered. The resulting filtrate is the saturated leonite solution. Using the saturated leonite solution reduces the dissolution of leonite during the ultrasonic and flotation processes.

[0008] In the above scheme, the preparation temperature of the saturated leonite solution and the ultrasonic treatment temperature are both 20-30°C.

[0009] In the above scheme, the ultrasonic power is controlled at 100~300W, and the ultrasonic frequency is controlled at 20~60kHz. The ultrasonic treatment time corresponding to this condition does not exceed 80min.

[0010] In this approach, after ultrasonic treatment, the mixture is filtered and the resulting solid is thoroughly dried, yielding a soft leonite with cracks and depressions on its surface. By strictly controlling the ultrasonic power, frequency, and treatment time, the surface morphology of the leonite particles undergoes a dramatic change, creating more cracks and depressions. This significantly increases the particles' specific surface area and adsorption sites, thereby enhancing subsequent flotation efficiency.

[0011] The present invention also provides an application of the above method in the flotation of soft leonite. The specific process of the application includes: mixing the soft leonite with cracks and depressions on the surface prepared above with a flotation medium and a collector for flotation to obtain the soft leonite.

[0012] In the above solution, the collector is selected from at least one of sodium dodecylbenzenesulfonate (SDBS) and sodium dodecylsulfonate (SDS).

[0013] In the above solution, the flotation medium is a saturated leonite solution.

[0014] In the above scheme, the amount of leonite particles added to each liter of flotation medium during flotation is 0.2-0.3 kg, and the amount of collector added is 0.025-0.25 g.

[0015] In the above scheme, the stirring rate during the flotation process is 1000~2000rpm, and the flotation time under this condition is 3~10min.

[0016] In the above scheme, after flotation, filtration is performed and the obtained solid is fully dried at 30-45° C. to obtain the leonite concentrate.

[0017] The present invention effectively regulates the surface morphology and structural characteristics of soft potassium magnesium alum mineral particles through the physicochemical effects of ultrasonic cavitation, micro-jet and acoustic disturbance, thereby improving their hydrophobicity and flotation effect. In addition, ultrasonic waves can also remove impurities on the surface of mineral particles and increase the roughness, enhance the adhesion of bubbles and activate surface active sites, and ultimately improve the adsorption effect of collectors. Compared with traditional methods such as developing new collectors and optimizing flotation parameters, the present invention solves the following problems at the same time: (1) How to improve the hydrophobicity and floatability of soft potassium magnesium alum mineral particles simply and at low cost; (2) How to enhance the adsorption performance of soft potassium magnesium alum minerals on flotation reagents; (3) How to improve the flotation efficiency of soft potassium magnesium alum minerals without introducing too many chemical reagents; (4) How to enhance the flotation effect of soft potassium magnesium alum minerals with low energy consumption and green environmental protection, so that it has good industrial adaptability and promotion value.

[0018] In summary, the advantages of the present invention are mainly reflected in the following points: (1) Compared with the traditional method of direct flotation of kaolinite, the present invention introduces ultrasonic pretreatment technology, which effectively increases the surface roughness of kaolinite mineral particles by utilizing cavitation effect, microjet effect and thermal effect, enhances the adsorption efficiency of collector, and ultimately significantly improves flotation selectivity and recovery rate without changing the type and dosage of collector.

[0019] (2) Compared with the conventional practice of improving flotation performance by increasing the type or dosage of reagents, the present invention optimizes the surface properties of soft potassium magnesium sulfate minerals through physical strengthening means, greatly reducing reagent consumption, which not only reduces the cost of raw materials but also avoids the introduction of additional impurities. It has the advantages of being green and environmentally friendly, and is in line with the current green development of mineral resources and the "dual carbon" policy orientation.

[0020] (3) The present invention is applicable to soft potassium magnesium alum deposits with scarce resources, low grade, and difficult to process by traditional processes. It is particularly suitable for promotion and application in salt lake mining areas in Qinghai, Qarhan, Golmud, and other regions, where market demand is urgent. According to calculations, if the present invention is promoted and applied in salt lake potash fertilizer enterprises, the flotation recovery rate of soft potassium magnesium alum can be increased by more than 10%. It is estimated that more than 300 tons of potassium chloride or potassium sulfate products can be recovered per 10,000 tons of ore. According to current market prices, the annual economic benefits can exceed 1 billion yuan, which has good economic return potential.

[0021] (4) The method of the present invention can be seamlessly integrated with existing mineral processing equipment. The equipment has strong versatility and low energy consumption, making it suitable for large-scale promotion and application. Based on the existing flotation process and equipment, only an ultrasonic pretreatment module needs to be added, without the need for major modifications to the existing production line. It has high replicability and industrial promotion value. Related ultrasonic equipment has been widely used in other fields (such as fine chemicals and pharmaceuticals), and the manufacturing cost has been declining year by year, so it has good engineering economics. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 These are SEM comparison photos of the soft potassium magnesium sulfate before and after ultrasound in Examples 1-4 and Comparative Example 1.

[0023] Figure 2 This is a comparison chart of the flotation recovery rates of leonite before and after ultrasound in Examples 1-4 and Comparative Example 1.

[0024] Figure 3 This is a comparison of the contact angles of langbeinite before and after ultrasound treatment with sodium dodecylbenzenesulfonate in Examples 1-4 and Comparative Example 1.

[0025] Figure 4 This is a diagram of the action mechanism of sodium dodecylbenzenesulfonate and soft potassium magnesium sulfate. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to fully understand the technical solutions and beneficial effects of the present invention, the following is further described in detail with reference to specific embodiments and accompanying drawings. It should be emphasized that the following embodiments are only preferred embodiments of the present invention, and any simple improvements or substitutions made on this basis will fall within the scope of protection of the present invention.

[0027] The leonite ore samples used in various embodiments of the present invention are all derived from artificially synthesized pure leonite solid.

[0028] The calculation formula of the recovery rate in each embodiment of the present invention is as follows: ε=m1 / (m1+m2) Among them, ε is the recovery rate, %; m1 is the concentrate mass, g; m2 is the tailings mass, g.

[0029] The classic first-order model fitting formula is as follows: R=R ∞ [1-e^ (-kt) ] Wherein, R is the cumulative recovery rate,%;R ∞ is the theoretical maximum recovery rate, %, k is the flotation rate; t is the flotation time, s.

[0030] Example 1 The leonite ore sample is crushed and sieved to obtain leonite particles with a target particle size of 0.074-0.15 mm. Excess leonite particles are added to 25°C water and stirred thoroughly. After the solids no longer dissolve (solid mass does not decrease), the leonite solution is filtered to obtain a saturated leonite solution (i.e., flotation mother liquor).

[0031] Screened leonite particles were added to a saturated leonite solution at a mass ratio of 1:4. The resulting mixture was then ultrasonically pretreated in a 25°C water bath at a power of 150 W, a frequency of 37 kHz, and a duration of 30 min. After ultrasonic pretreatment, the mixture was filtered and the resulting solid particles were dried in a 40°C oven for 24 h to obtain leonite particles with modified surface morphology. Samples were then collected for SEM analysis and compared to those before and after ultrasonic treatment.

[0032] Single-mineral flotation experiments were then conducted. A slurry was prepared by mixing 15 g of surface-modified leonite particles with 60 mL of saturated leonite solution. After stirring at 1800 rpm for 2 minutes, 9 mg of SDBS collector was added to the slurry. Flotation and flotation kinetics experiments were then conducted by aeration and flotation scraping. At 0s, 30s, 60s, 100s, 140s, 180s, and 240s, samples were collected, filtered, and dried to obtain leonite concentrate, which was then fitted using the aforementioned classical first-order model.

[0033] Example 2 This embodiment is basically the same as embodiment 1, except that the ultrasonic time is changed from 30 min to 45 min.

[0034] Example 3 This embodiment is basically the same as embodiment 1, except that the ultrasonic time is changed from 30 min to 60 min.

[0035] Example 4 This embodiment is basically the same as embodiment 1, except that the ultrasonic time is changed from 30 min to 75 min.

[0036] Comparative Example 1 This comparative example is basically the same as Example 1, except that the ultrasonic time is changed from 30 min to 0 min, i.e., no ultrasonic pretreatment is performed.

[0037] In order to fully understand the effects of ultrasonic pretreatment and flotation, the following tests were carried out: (1) Scanning electron microscope (SEM) test The SEM photos of soft potassium magnesium sulfate particles at ultrasonic 0min (ie, comparative example 1), 30min (ie, example 1), 45min (ie, example 2), 60min (ie, example 3), and 75min (ie, example 4) are as follows: Figure 1 Figure a shows a leonite crystal without ultrasonic treatment. The crystal surface is relatively smooth, with only a small amount of debris adhering to it. Figure b shows a leonite crystal after 30 minutes of ultrasonic treatment. Numerous cracks and depressions have developed on the crystal surface, and the original debris has been desorbed from the crystal surface. This is because the propagation of ultrasound induces macroscopic fluctuations in the system and high-speed particle collisions, which promote the dispersion of fine particles and their desorption from the leonite surface. As shown in Figures cde, with increasing ultrasonic pretreatment time (45 minutes to 75 minutes), the cracks and depressions on the crystal surface become increasingly intense due to the continuous high-frequency vibration of the ultrasound, even leading to structural damage. This indicates that ultrasonic pretreatment indeed enhances the surface characteristics of leonite particles. Under the action of ultrasound, the leonite crystal surface is more prone to cracking, breaking, and shedding. This increases the specific surface area of ​​the crystal, exposes more adsorption sites, and increases the probability of surface interaction between the reagent and the leonite particles, creating more favorable conditions for leonite flotation and ultimately affecting the flotation behavior of leonite.

[0038] (2) Flotation recovery test The flotation recovery test results in Examples 1-4 and Comparative Example 1 are as follows: Figure 2 shown.

[0039] Figure 2 The left figure shows the effect of ultrasonic treatment time on flotation recovery at the same flotation time (240 seconds). As can be seen, the leonite recovery rate gradually increases and then remains stable with increasing ultrasonic treatment time. When the ultrasonic treatment time increases from 0 to 60 minutes, the leonite recovery rate increases from 79.85% to 90.24%. This result demonstrates that ultrasonic treatment does promote and improve the flotation of leonite.

[0040] Figure 2 The figure on the right shows the flotation kinetics of leonite at different ultrasonic treatment times. As can be seen from the figure, under the same flotation conditions, the sonicated leonite has a faster flotation rate, and potassium recovery increases with increasing sonication time. Combined with the results of the classical first-order model fit, the k value (i.e., the flotation rate) is maximized after 60 minutes of ultrasonication, which is more conducive to the rapid flotation of leonite. These experimental results confirm that ultrasonic treatment effectively assists the flotation of leonite.

[0041] (3) Contact angle test The leonite particles before and after ultrasound in Examples 1-4 and Comparative Example 1 were used as raw materials, and were added to a saturated leonite solution and a 0.6% SDBS aqueous solution, respectively. The contact angles were then measured. The results were as follows: Figure 3 shown.

[0042] As can be seen from the first row of photos, the contact angle of the leonite particles shows little or no change before and after ultrasonic treatment. However, when the collector SDBS is present in the solution, the treated leonite particles exhibit improved hydrophobicity, with their contact angle significantly increasing. Specifically, after 60 minutes of ultrasonication, the contact angle of the leonite particles increases from 47° to 75°. This indicates that after ultrasonic treatment, the rough surface of the leonite becomes more hydrophobic in the presence of the collector.

[0043] The mechanism of action of SDBS and kainite is as follows Figure 4 As shown in Figure 2 , the reaction between leonite particles and the SDBS reagent creates O-Mg bonds. The OS groups of the sulfonate groups in SDBS complex with magnesium atoms on the surface of the leonite, making magnesium an adsorption site. Experiments testing the relative elemental content of the surface of the leonite before and after ultrasonic treatment revealed an increase in magnesium content after ultrasonic treatment. This increase in magnesium, which serves as an adsorption site, clearly facilitates the adsorption of SDBS on the surface of the leonite, promoting its flotation. This explains the increased flotation recovery after ultrasonic treatment.

Claims

1. A method for controlling the surface morphology of langbeinite, characterized in that The method comprises: adding soft leonite particles into a solution, performing ultrasonic treatment and then performing solid-liquid separation to obtain soft leonite with cracks and depressions on the surface.

2. The method according to claim 1, wherein: The particle size of the soft langbeinite particles is 0.074-0.15 mm.

3. The method according to claim 1, wherein: The solution is specifically a saturated leonite solution, and its preparation method includes: mixing excess leonite with water and stirring thoroughly, and filtering when the solids no longer decrease, and the obtained filtrate is the saturated leonite solution.

4. The method according to claim 3, wherein: The preparation temperature of the saturated leonite solution and the ultrasonic treatment temperature are both 20-30°C.

5. The method according to claim 1, wherein: The ultrasonic power is 100~300W, the ultrasonic frequency is 20~60kHz, and the ultrasonic treatment time does not exceed 80min.

6. Use of any one of the methods of claims 1 to 5 in the flotation of philasite.

7. The use according to claim 6, characterized in that The specific process of this application includes: mixing the prepared soft leonite particles with cracks and depressions on the surface with a flotation medium and a collector to carry out flotation to obtain the soft leonite concentrate.

8. The use according to claim 7, characterized in that: The collector is selected from at least one of sodium dodecylbenzenesulfonate and sodium dodecylsulfonate, and the flotation medium is a saturated kainite solution.

9. The use according to claim 7, characterized in that: During flotation, the addition amount of soft potassium magnesium sulfate particles is 0.2-0.3 kg / L flotation medium, and the addition amount of collector is 0.025-0.25 g / L flotation medium.

10. The use according to claim 7, characterized in that: The stirring rate during the flotation process is 1000-2000 rpm. After the flotation, the solid-liquid separation is carried out and the solid is placed at 30-45°C and fully dried to obtain the soft potassium sulfate concentrate.

Images