Application of glyphosate and its derivatives, salts as inhibitors in magnesium removal of magnesium phosphate ore by reverse flotation, flotation reagent and flotation method

Abstract

The application relates to application of glyphosate and derivatives and salts thereof as inhibitors in magnesium ore reverse flotation des-magnesia, flotation reagents and a flotation method. The application applies glyphosate and derivatives and salts thereof as inhibitors in magnesium ore reverse flotation des-magnesia, can efficiently and selectively inhibit apatite, enhances the difference in floatability between apatite and dolomite, thereby improving the grade and recovery rate of P2O5 in the concentrate, and reducing the MgO content in the concentrate.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, and more specifically, to the application of glyphosate and its derivatives, salts as inhibitors in reverse flotation demagnesification of magnesian phosphate rock, flotation reagents, and flotation methods. Background Technology

[0002] Phosphate rock, as a strategic non-metallic mineral resource, is non-renewable and irreplaceable in industrial applications, making its efficient utilization crucial. my country's phosphate rock resources are characterized by being "abundant but not plentiful." According to the latest exploration data from the Ministry of Land and Resources, 90.8% of domestic phosphate deposits are of medium to low grade, with an average P2O5 grade of only 16.85%, of which collophane accounts for approximately 70% of the national total reserves. These deposits generally feature dense coexistence of magnesian gangue minerals and phosphate minerals, with fine-grained intergrowth. Effective beneficiation and enrichment are essential to meet the raw material grade requirements for industrial applications such as phosphate fertilizer preparation and new energy material processing.

[0003] In the existing mineral processing technology system, reverse flotation for magnesium removal has become the mainstream technology for processing magnesium-calcareous phosphate rock due to its advantages of strong adaptability and high separation efficiency. The key to this process system lies in achieving selective separation of phosphate minerals and magnesium gangue through reagent regulation. The choice of depressant directly affects the flotation selectivity index and resource utilization rate. Currently, industrial applications mainly use inorganic acid depressants such as sulfuric acid and phosphoric acid, supplemented by improved reagents such as W-98 (phosphate ester derivative) and PT-4 (small molecule organic acid). Although these depressant systems can achieve basic separation effects, there are still three key technical defects: First, the selective inhibition efficiency of depressants on magnesium-bearing minerals is insufficient, making it difficult to stably control the MgO content in the concentrate to the high-quality standard of below 1.0%; second, the unit dosage of existing reagents is too high (generally reaching 3-5 kg / t), which significantly increases the beneficiation cost and brings environmental pressure; third, the P2O5 loss rate in tailings is as high as 7% or more, resulting in a serious waste of phosphorus resources. Especially for magnesian phosphate rock with fine crystal size and low mineral liberation, traditional inhibitor systems are no longer sufficient to meet the demands of new mineral processing equipment for improved reagent efficiency.

[0004] Therefore, developing flotation depressants with novel mechanisms of action and high selectivity and low consumption has become an urgent technological need to improve the utilization rate of low- and medium-grade phosphate rock resources in my country and promote the upgrading of the phosphate chemical industry. Summary of the Invention

[0005] Based on the aforementioned technical problems in the existing technology, this invention uses glyphosate and its derivatives and salts as inhibitors in the reverse flotation demagnesification of magnesium phosphate rock. It can efficiently and selectively inhibit apatite, enhance the difference in floatability between apatite and dolomite, thereby improving the grade and recovery rate of P2O5 in the concentrate and reducing the content of MgO in the concentrate.

[0006] Specifically, the glyphosate and its derivatives and salts include at least one of glyphosate, glyphosate, diglyphosate, glyphosate ammonium salt, glyphosate potassium salt, and glyphosate sodium salt.

[0007] This invention uses glyphosate and its derivatives and salts as inhibitors in the reverse flotation demagnesification of magnesium phosphate rock. The mechanism of action is as follows:

[0008] Glyphosate and its derivatives, as well as its salt inhibitors, possess suitable chelating ability and form hydrophilic spatial configurations for collophane, which are key to ensuring high selectivity and good inhibition of phosphorus-containing minerals. Specifically, glyphosate and its derivatives, as well as its salt inhibitors, belong to the phosphonic acid amino acid derivatives. Their molecular structure combines a glycine skeleton (-NH-CH2-COOH) with a phosphonic acid group (-PO3H2), making them multifunctional synergistic organophosphorus compounds. Agents containing a glycine core exhibit stronger chelating selectivity for the low-activity calcium on the collophane surface. The nitrogen atom in the glycine amino group and the oxygen atom in the carboxyl group provide three additional coordination sites, forming closed-ring chelates with calcium sites on the apatite surface. The stability constant log K is approximately 10-12, while the log K of ordinary organophosphonates is only 5-8. Furthermore, its glycine core structure exhibits zwitterionic properties in the slurry solution. Under weakly alkaline conditions, the protonated amino group can form electrostatic attraction with the negatively charged phosphorus-containing minerals on the surface, achieving dual fixation through electrostatic adsorption and chemical chelation. After the agent is adsorbed onto the surface of phosphate rock, the carbon chain of the glycine core has a certain spatial configuration, which can more effectively block the adsorption of the collector on the mineral surface.

[0009] In the reverse flotation separation process of phosphorus-containing minerals and gangue minerals such as dolomite, organophosphate reagents containing glycine cores achieve efficient inhibition by targeting calcium sites on the surface of phosphorus-containing minerals. The multifunctional group system formed by amino, carboxyl, and phosphonic acid groups in its molecular structure can specifically chelate with calcium atoms linked to phosphorus-oxygen bonds on the surface of phosphorus-containing minerals. The protonated amino groups can form electrostatic attraction with the negatively charged phosphate groups on the surface of phosphorus-containing minerals. Through electrostatic adsorption and chemical chelation, a stable chemical adsorption layer is formed. This adsorption layer can effectively block the interaction between the collector and the surface of phosphorus-containing minerals, thereby inhibiting further adsorption of the collector on the surface of phosphorus-containing minerals. At the same time, the collector can selectively adsorb onto magnesium sites on the surface of gangue minerals such as dolomite through active chelating groups such as carboxyl groups, making the gangue minerals such as dolomite floatable and floating with bubbles. Ultimately, this achieves efficient separation of phosphorus-containing minerals and gangue minerals such as dolomite, thereby improving the grade and recovery rate of P2O5 in the concentrate and reducing the content of MgO in the concentrate.

[0010] This invention also provides a combined reagent for magnesium removal by reverse flotation of magnesia phosphate rock, comprising an inhibitor and a collector, wherein the inhibitor is glyphosate and its derivatives or salts. In the reverse flotation process of magnesia phosphate rock, this invention precisely controls the pulp pH environment by adding a pH adjuster, synergistically optimizing the adsorption selectivity of other reagent molecules on the surfaces of phosphorus-containing minerals and dolomite minerals, thereby improving reagent efficiency. The added collector targets and identifies magnesia gangue dolomite, enhancing the floatability of dolomite, thus ensuring the efficient flotation separation of phosphorus-containing minerals and dolomite.

[0011] In some embodiments, the glyphosate and its derivatives and salts include at least one of glyphosate, glyphosate, diglyphosate, glyphosate ammonium salt, glyphosate potassium salt, and glyphosate sodium salt.

[0012] In some embodiments, the collector includes sodium oleate.

[0013] In some embodiments, the combined pharmaceutical agent further includes a pH adjuster, which includes sulfuric acid and / or sodium hydroxide.

[0014] This invention also provides a method for demagnesium removal from magnesian phosphate rock via reverse flotation, the method comprising the following steps:

[0015] S1. Grind the raw ore and prepare the slurry to obtain the slurry;

[0016] S2. Add any of the above-mentioned combined reagents to the slurry and perform flotation to obtain concentrate and tailings.

[0017] In some embodiments, in step S2, the amount of the inhibitor is 30-200 mg / L; preferably, it is 40-180 mg / L.

[0018] In some embodiments, in step S2, the amount of the collector is 50-500 mg / L.

[0019] In some embodiments, in step S1, the raw ore includes fluorapatite and dolomite, and the raw ore has a P2O5 grade of 13-26% and an MgO grade of 3-15%.

[0020] In some embodiments, in step S1, the slurry concentration is 20-40 wt%.

[0021] In some embodiments, in step S1, the raw ore is ground to a particle size of -0.074 mm with a content of ≥80%.

[0022] In some embodiments, step S2 specifically involves: adding a pH adjuster to the slurry to adjust the pH of the slurry to 5-12, then adding an inhibitor and a collector in sequence, and performing flotation to obtain concentrate and tailings.

[0023] In some implementations, the slurry pH is adjusted to 6-9.

[0024] In some embodiments, the method for demagnesizing magnesian phosphate rock by reverse flotation includes the following steps:

[0025] S1. Grind the raw ore to a particle size of -0.074 mm or more, adjust the slurry to obtain a slurry with a concentration of 20-40 wt%.

[0026] S2. Add a pH adjuster to the slurry to adjust the pH value of the slurry to 5-12, and then add an inhibitor and a collector in sequence to carry out flotation to obtain concentrate and tailings.

[0027] In some implementations, the flotation process includes a roughing process and a cleaning process; specifically, the method includes the following steps:

[0028] S1. Grind the raw ore to a particle size of -0.074 mm or more, adjust the slurry to obtain a slurry with a concentration of 20-40 wt%.

[0029] S2-1. Add a pH adjuster to the slurry to adjust the pH value of the slurry to 5-12, and then add an inhibitor and a collector in sequence to carry out flotation to obtain rougher concentrate and rougher tailings.

[0030] S2-2. Add a collector to the rough concentrate and perform flotation to obtain a fine concentrate and fine tailings.

[0031] In some embodiments, in step S2-1, the amount of inhibitor added is 30-200 mg / L, and the amount of collector added is 50-500 mg / L.

[0032] In some embodiments, in step S2-2, the amount of collector added is 100-200 mg / L.

[0033] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0034] (1) The inhibitor provided by the present invention is a multifunctional synergistic organophosphorus compound with strong selectivity and adsorption stability. It has excellent selective inhibition effect on phosphorus-containing minerals such as fluorapatite in magnesium phosphate rock. Adding this type of compound / salt as an inhibitor during the reverse flotation process of magnesium phosphate rock can significantly improve the separation efficiency of phosphorus-containing minerals and gangue mineral dolomite in the reverse flotation process of magnesium phosphate rock.

[0035] (2) These compounds are highly efficient, low-cost, safe to use, widely available, non-toxic, and biodegradable as inhibitors. They can also effectively achieve high P2O5 recovery, low MgO content and low flotation reagent consumption for magnesium phosphate rock in a wide pH range (5-12).

[0036] (3) This type of compound is highly adaptable as an inhibitor and is suitable for hard water (high Ca2+). 2+ Mg 2+ In flotation environments with large pH fluctuations, there is no need to add large amounts of water softener or pH adjuster, simplifying the process.

[0037] (4) These compounds have good environmental compatibility as inhibitors. The glycine fragments contained in the reagent molecules are easily biodegradable and the phosphonic acid group has no long-term residual risk, which is in line with the development trend of green flotation.

[0038] (5) The flotation separation method of the present invention is simple in process. By adding a low amount of inhibitor, the floatability of phosphorus-containing minerals can be effectively suppressed without inhibiting the dolomite minerals due to the complexation of glycine and phosphate. This enhances the difference in floatability between phosphorus-containing minerals and gangue minerals such as dolomite, and significantly reduces the negative impact and economic cost of subsequent wet phosphoric acid production and ammonium phosphate production. Attached Figure Description

[0039] Figure 1 The following are potential kinetic diagrams of mineral surfaces before and after the action of the inhibitor and collector provided by the present invention; wherein, (a) is the potential kinetic diagram of the action on the surface of dolomite; and (b) is the potential kinetic diagram of the action on the surface of apatite.

[0040] Figure 2 The test results of the contact angle of mineral surfaces before and after treatment with the inhibitor and collector provided by the present invention; wherein, (a) figure shows the test results of the contact angle of dolomite surface; (b) figure shows the test results of the contact angle of apatite surface;

[0041] Figure 3 The flotation process flow diagrams and reagent regimes for Examples 1-2 and Comparative Example 1 of this invention are shown below.

[0042] Figure 4 The flotation process flow diagrams and reagent regimes for Embodiment 3 and Comparative Examples 2-4 of this invention are shown below.

[0043] Figure 5 The image shows the product obtained in Embodiment 3 of the present invention. Detailed Implementation

[0044] Numerous specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many other ways different from those described herein, and similar modifications can be made by those skilled in the art without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0046] Examples 1-2 and Comparative Example 1 below are the results of flotation tests of artificial mixed minerals in which pure apatite and dolomite are uniformly mixed at a mass ratio of 1:1.

[0047] Example 1

[0048] Pure apatite and dolomite minerals with a particle size of -0.075 to +0.037 mm were uniformly mixed at a mass ratio of 1:1 to obtain a mixed ore. 2 g of the artificially mixed ore was added to 35 mL of deionized water in a flotation cell, and the mixture was stirred and adjusted at 1990 r / min to obtain a slurry. The order and process of adding flotation reagents are as follows: Figure 3 As shown, the pH of the slurry was adjusted to 8, and 52 mg / L of glyphosate inhibitor and 61 mg / L of sodium oleate collector were added sequentially. Then, reverse flotation was performed for 5 min to obtain tailings and concentrate products. The products were filtered, dried, and weighed, and their elemental contents were determined and the elemental recovery rate was calculated. The results are shown in Table 1.

[0049] Under these conditions, the dynamic potential test results on the surfaces of dolomite and apatite before and after the inhibitor treatment are as follows: Figure 1 As shown in Figures (a) and (b), the water phase contact angle test results are as follows: Figure 2 As shown in Figures (a) and (b).

[0050] Example 2

[0051] Unlike Example 1, Example 2 added 132 mg / L of inhibitor during the flotation slurry preparation process to compare the inhibitor dosage with the flotation efficiency. The remaining operation steps, collector dosage and raw ore composition were the same as in Example 1. The results are shown in Table 1.

[0052] Comparative Example 1

[0053] Unlike Example 1, no inhibitor was added during the flotation slurry preparation process in Comparative Example 1, which served as a blank control for the experiment. The remaining operation steps, reagent dosages, and raw ore composition were the same as in Example 1, and the results are shown in Table 1.

[0054] Table 1 Results of flotation tests of artificially mixed ores in Examples 1-2 and Comparative Example 1

[0055]

[0056] As shown in Table 1, in the reverse flotation system without the addition of inhibitors, the P2O5 grade in the concentrate was only 6.99%, while the MgO grade was as high as 17.98%, corresponding to recoveries of 8.96% and 41.39%, respectively. This result indicates that apatite and dolomite gangue minerals cannot be effectively separated without inhibitors. When 52 mg / L of the inhibitor of this invention was added, the P2O5 grade in the concentrate significantly increased to 35.01%, while the MgO grade decreased to 1.61%, with recoveries reaching 87.54% and 12.67%, respectively, confirming the excellent selective inhibition performance of this inhibitor on the apatite / dolomite system. It is worth noting that when the inhibitor dosage was increased to 162 mg / L, the P2O5 grade of the concentrate remained at 33.38%, and the MgO grade further decreased to 1.15%, with recoveries of 76.13% and 9.22%, respectively. This indicates that the inhibitor can still maintain high efficiency in inhibiting dolomite under excessive use conditions, and does not have a significant impact on the floatability of apatite.

[0057] Depend on Figure 1 and Figure 2 The test results show that after adding the inhibitor of this invention, the contact angle of the dolomite surface increased from 55.94° to 82.64°, indicating a significant enhancement in hydrophobicity, suggesting that the adsorption of the collector on the dolomite surface was not inhibited. In contrast, the contact angle of the apatite surface decreased from 46.36° to 39.24°, indicating enhanced hydrophilicity. This phenomenon stems from the preferential adsorption of the inhibitor molecules on the apatite surface, which, through strong chelation, hinders the adsorption process of the collector molecules, confirming the specific regulatory ability of this inhibitor on the apatite surface structure.

[0058] The mineral processing flow and reagent system of Embodiment 3 and Comparative Examples 2-4 of this invention are as follows: Figure 4 As shown.

[0059] Example 3

[0060] Low- to medium-grade magnesium phosphate ore from a certain area in Guizhou Province (P2O5 grade 23.01%, MgO grade 4.40%, main phosphorus mineral is fluorapatite, gangue mineral is mainly dolomite, containing magnetite, quartz and feldspar). Figure 4 As shown, the raw ore is ground to achieve a -0.074 mm particle size content of ≥90%, thus realizing the liberation of the target mineral. The slurry is then transferred to a 2 L flotation cell, and after adjusting the slurry concentration to 25%, the following operations are performed sequentially:

[0061] (1) Addition of inhibitor: Add glyphosate inhibitor 175 mg / L, and allow the drug to react fully at 3 min intervals;

[0062] (2) Addition of collector: Add 500 mg / L of sodium oleate as a collector;

[0063] (3) Reverse flotation operation: After continuous stirring for 5 minutes, collect the foam layer as tailings, and the remaining slurry is the mixed concentrate;

[0064] (4) Fine-grained operation: Add 100 mg / L of collector to the mixed concentrate and continue reverse flotation for 3 min to obtain concentrate and middlings products.

[0065] The raw ore, concentrate, and tailings products in this embodiment are as follows: Figure 5 As shown.

[0066] Comparative Example 2

[0067] The same raw ore and process parameters as in Example 3 were used, except that no inhibitors were added after grinding as a blank control group.

[0068] Comparative Example 3

[0069] After grinding, 600 mg / L of the inhibitor phosphate was added, and other operating parameters remained the same as in Example 3.

[0070] Comparative Example 4

[0071] After grinding, 250 mg / L of the inhibitor aminotrimethylenephosphonic acid (ATMP) was added, and the remaining process conditions were the same as in Example 3.

[0072] Table 2 Results of actual industrial flotation tests of phosphate rock in Example 3 and Comparative Examples 2-4

[0073]

[0074] As shown in Table 2, Example 3, using the reagent system of this invention, demonstrated significant advantages in the actual beneficiation of low-grade magnesian phosphate rock in a certain area of ​​Guizhou. The obtained concentrate had a P2O5 grade and recovery rate as high as 31.26% and 87.34%, respectively, while the MgO grade and recovery rate were only 0.82% and 11.97%. In contrast, the concentrate obtained by the conventional phosphoric acid process in Comparative Example 3 had a P2O5 grade and recovery rate of 30.63% and 81.64%, and a MgO grade and recovery rate of 1.34% and 18.69%, respectively, indicating a lower P2O5 recovery rate and a higher MgO content. The concentrate obtained by the novel ATMP organophosphonate in Example 4 had a P2O5 grade and recovery rate of 30.43% and 83.54%, and a MgO grade and recovery rate of 1.12% and 16.09%, respectively. Although the indicators were improved, they were still worse than those in Example 3. In addition, in terms of drug dosage, the inhibitor consumption in Example 3 was also significantly reduced, to only 175 mg / L.

[0075] In summary, the inhibitor provided by this invention can significantly improve the separation efficiency of phosphorus-containing minerals and gangue mineral dolomite in reverse flotation of magnesia phosphate rock. Furthermore, this type of inhibitor also possesses advantages such as safe use, environmental friendliness, low reagent consumption, excellent flotation adaptability and stability, wide availability, low cost, and non-toxicity.

[0076] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0077] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. The application of glyphosate and its derivatives and salts as inhibitors in reverse flotation demagnesification of magnesium phosphate rock, wherein the glyphosate and its derivatives and salts are at least one of glyphosate, glyphosate, diglyphosate, glyphosate ammonium salt, glyphosate potassium salt, and glyphosate sodium salt.

2. A combined reagent for magnesium removal by reverse flotation of magnesian phosphate rock, characterized in that, It includes an inhibitor and a collector, wherein the inhibitor is at least one selected from glyphosate, glyphosate, diglyphosate, glyphosate ammonium salt, glyphosate potassium salt, and glyphosate sodium salt.

3. The combined reagent for magnesium removal by reverse flotation of magnesia phosphate rock according to claim 2, characterized in that, The collector includes sodium oleate.

4. A method for magnesium removal by reverse flotation of magnesian phosphate rock, characterized in that, Includes the following steps: S1. Grind the raw ore and prepare the slurry to obtain the slurry; S2. Add the combined reagents according to any one of claims 2-3 to the slurry and perform flotation to obtain concentrate and tailings.

5. The method for demagnesium removal from magnesian phosphate rock by reverse flotation according to claim 4, characterized in that, In step S2, the amount of the inhibitor is 30-200 mg / L; and / or, the amount of the collector is 50-500 mg / L.

6. The method for demagnesium removal from magnesian phosphate rock by reverse flotation according to claim 4, characterized in that, In step S1, the raw ore includes fluorapatite and dolomite, and the P2O5 grade in the raw ore is 13-26%, and the MgO grade is 3-15%.

7. The method for demagnesium removal by reverse flotation of magnesian phosphate rock according to claim 4, characterized in that, In step S1, the slurry concentration is 20-40 wt%.

8. The method for demagnesium removal from magnesian phosphate rock by reverse flotation according to any one of claims 4-7, characterized in that, In step S2, specifically: A pH adjuster is added to the slurry to adjust the pH of the slurry to 5-12. Then, the inhibitor and collector are added in sequence, and flotation is carried out to obtain concentrate and tailings.

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