Method for removing magnesium from phosphate ore through reverse flotation and application

Abstract

The invention discloses a phosphate ore reverse flotation magnesium removal method and application, and the method comprises the following steps: S1, crushing, screening, grading and grinding phosphate ore containing calcium and magnesium to obtain phosphate rock powder; s2, water is added into the ground phosphate rock for pulp mixing, then the pH value is adjusted to 4.5-9.0, and ore pulp is obtained; s3, an inhibitor solution and a collecting agent solution are sequentially added into the ore pulp, flotation impurity removal is conducted, and tailings and phosphate concentrate are obtained; the inhibitor solution is fulvic acid and / or fulvic acid salt solution; according to the method, flotation is conducted through the inhibitor fulvic acid or the salt thereof, the method has the advantages of being free of phosphorus and pollution, small in dosage, mild in applicable pH range, free of corrosion damage to flotation equipment and the like, impurity removal treatment of the calcium magnesium phosphate ore can be achieved only through the reverse flotation short process, and the flotation impurity removal effect is good.

Description

Technical Field

[0001] The invention relates to the technical field of ore dressing, and in particular to a method for reverse flotation and magnesium removal of phosphate ore and its application. Background Art

[0002] In addition to the target phosphate minerals, medium and low-grade phosphate ores are often accompanied by a certain proportion of (calcium) magnesium and siliceous gangue. These gangue minerals have a great impact on the subsequent wet phosphoric acid preparation process. Among them, excessive magnesium impurities will significantly increase the consumption of sulfuric acid in the wet phosphoric acid process, reduce product quality, and are unfavorable to phosphorus chemical production. Therefore, the development and research of phosphate ore removal technology is particularly important. Dolomite is the most important calcium-magnesium gangue mineral in phosphate ore, but the surface properties of dolomite and target phosphate minerals are relatively similar, which makes the commonly used fatty acid collectors in industry have poor selectivity for the capture of the two and low sorting efficiency, and cannot achieve effective separation of target phosphate minerals and dolomite, which seriously affects the efficient development and utilization of medium and low-grade phosphate resources.

[0003] Flotation is often used to remove impurities from phosphate ore, and in this process, efficient flotation agents play a vital role. Highly selective suppression and impurity removal has always been the focus of phosphate ore beneficiation and purification process technology.

[0004] Therefore, it is necessary to provide an efficient method for removing impurities from phosphate ore by reverse flotation. Summary of the invention

[0005] In view of this, the present application provides a method and application of reverse flotation demagnesiumization of phosphate ore, which is used to solve the problem of how to achieve efficient reverse flotation demagnesiumization of phosphate ore.

[0006] In order to achieve the above technical objectives, this application adopts the following technical solutions: In a first aspect, the present application provides a method for reverse flotation of phosphate ore to remove magnesium, comprising the following steps: S1. crushing, screening, grading and grinding calcium-magnesium phosphate ore to obtain phosphate rock powder; S2. After adding water to the phosphate rock powder to prepare the slurry, the pH value is adjusted to 4.5-9.0 to obtain a slurry; S3. Add inhibitor solution and collector solution to the ore pulp in sequence to carry out flotation removal to obtain tailings and phosphate concentrate; the inhibitor solution is fulvic acid and / or fulvic acid salt solution.

[0007] Preferably, in step S1, in the phosphate rock powder, particles with a particle size of ≤74 μm account for 70-95 wt %.

[0008] Preferably, in step S2, the concentration of the slurry is 20-36wt%.

[0009] Preferably, in step S3, the collector comprises sodium oleate.

[0010] Preferably, in step S3, the concentration of the inhibitor solution is 0.01-0.2 wt %, and the ratio of the inhibitor to the slurry is 20-30 mg:1L.

[0011] Preferably, in step S3, the concentration of the collector solution is 1-4wt%, and the solid-liquid ratio of the collector to the slurry is 40-200mg:1L.

[0012] Preferably, in step S3, after adding the inhibitor solution, add the collector solution after an interval of 2-4 minutes.

[0013] Preferably, the method further comprises filtering and drying the tailings.

[0014] In a second aspect, the present application provides a phosphate concentrate, in which the P2O5 grade is 34.58-37.89% and the MgO grade is ≤0.95%.

[0015] In a third aspect, the present application provides an application in the field of phosphate ore sorting and purification.

[0016] The beneficial effects of this application are as follows: The present invention uses the inhibitor fulvic acid or its salt for flotation, which has the advantages of being phosphorus-free, pollution-free, small in dosage, suitable for a mild pH range, and having no corrosion damage to flotation equipment. The impurity removal of calcium-magnesium phosphate ore can be achieved only through a short reverse flotation process, which has significant advantages over the forward-reverse and reverse-forward flotation processes and greatly reduces equipment investment and operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a process flow chart of this application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] The present application provides a method for reverse flotation of phosphate ore to remove magnesium, comprising the following steps: S1. crushing, screening, grading and grinding calcium-magnesium phosphate ore to obtain phosphate rock powder; S2. After adding water to the phosphate rock powder to prepare the slurry, the pH value is adjusted to 4.5-9.0 to obtain a slurry; S3. Add inhibitor solution and collector solution to the ore pulp in sequence to carry out flotation removal to obtain tailings and phosphate concentrate; the inhibitor solution is fulvic acid and / or fulvic acid salt solution.

[0020] Fulvic acid is a multiphase, amorphous aliphatic aromatic organic acid compound, which is synthesized by microorganisms from plant residues. It contains a large number of active groups such as phenolic hydroxyl and carboxyl in its structure, so it can interact with metal ions such as oxides, calcium, magnesium, and organic matter including toxic and harmful substances. When the inhibitor of the present application is adsorbed on a certain mineral surface, on the one hand, it reduces the hydrophobicity of the mineral surface, and on the other hand, it hinders the action of the collector on the mineral surface, thereby inhibiting the floating of the mineral. In addition, fulvic acid or its salt is a phosphorus-free, non-toxic environmentally friendly agent, which can also play a good control role in the migration and transformation of various organic pollutants and heavy metals in the water body, and selectively inhibits the floating of the target phosphate mineral, expands the difference in flotation behavior between phosphate minerals and dolomite, and realizes reverse flotation to remove dolomite impurity components to obtain a flotation phosphate concentrate product.

[0021] In addition, the inhibitor of the present application has a strong selective inhibitory effect on the target phosphate minerals in the phosphate ore, but has no significant effect on the calcium-magnesium carbonate mineral dolomite. By using the inhibitor of the present application, efficient flotation and impurity removal of calcium-magnesium phosphate ore can be achieved. The main principle is that compared with the calcium and magnesium atoms exposed on the surface of dolomite, the calcium atoms exposed on the surface of phosphate minerals tend to be more away from the center of the lattice. The inhibitor structure contains a large number of active groups such as hydroxyl and carboxyl groups, which are more likely to form stable chelating components with the calcium atoms exposed on the surface of phosphate minerals and strongly adsorb on the surface of phosphate minerals. The attraction between the hydrophilic groups and water molecules is enhanced, which strengthens the hydrophilicity of the surface of the phosphate minerals. Therefore, the floatability of the phosphate minerals decreases, and the floating is inhibited. Dolomite still maintains a good floatability, and the floating is not affected, which finally realizes the expansion of the difference in flotation behavior between phosphate minerals and dolomite.

[0022] In some embodiments, in step S1, in the phosphate rock powder, particles with a particle size of ≤74 μm account for 70-95 wt %.

[0023] In some embodiments, in step S2, the concentration of the slurry is 20-36 wt %.

[0024] In some embodiments, in step S3, the collector comprises sodium oleate.

[0025] In some embodiments, in step S3, the concentration of the inhibitor solution is 0.01-0.2wt%, and the ratio of the inhibitor to the slurry is 20-30mg:1L.

[0026] In some embodiments, in step S3, the concentration of the collector solution is 1-4wt%, and the solid-liquid ratio of the collector to the slurry is 40-200mg:1L.

[0027] In some embodiments, in step S3, after adding the inhibitor solution, add the collector solution after an interval of 2-4 minutes.

[0028] In some embodiments, the tailings may also be filtered and dried.

[0029] The present application provides a phosphate concentrate, in which the P2O5 grade is 34.58-37.89% and the MgO grade is ≤0.95%.

[0030] In a third aspect, the present application provides an application in the field of phosphate ore sorting and purification.

[0031] The present application can selectively inhibit the flotation of apatite by adding the inhibitor fulvic acid or its salt, effectively expanding the difference in floatability between phosphate minerals and gangue minerals such as dolomite and calcite in phosphate ore, thereby realizing the separation of phosphate minerals from minerals such as dolomite and calcite through the reverse flotation method, removing calcium and magnesium impurities, and improving the product quality of the flotation phosphate concentrate. Fulvic acid or its salt can play a role under milder slurry conditions, significantly reducing the adverse effects of the use of traditional inorganic acid inhibitors, and can greatly simplify the existing phosphate flotation process. The decontamination treatment of low-grade phosphate ore containing calcium and magnesium can be achieved only through the reverse flotation process. At the same time, the inhibitor fulvic acid or its salt has obvious chemical structure advantages, and is characterized by low cost, non-toxicity, non-pollution, multi-dispersion, and degradability.

[0032] The present solution is further described below through specific embodiments.

[0033] Example 1 A method for reverse flotation of phosphate ore to remove magnesium comprises the following steps: S1. Crushing and grinding: Use a jaw crusher to crush and screen calcium-magnesium phosphate ore (chemical composition includes P2O5 26.14%, MgO 4.99%, CaO 40.73%, Al2O3 2.17%, Fe2O3 1.49%, SiO2 7.81%, K2O 0.93%) to obtain powder with a particle size of less than 2 mm. Then add the crushed powder to a ceramic ball mill and grind it until the particle size of the powder is less than 74μm, which is phosphate rock powder; S2. Mechanical slurry preparation: the phosphate rock powder is mixed evenly with ultrapure water at room temperature (25°C) to obtain a mixture with a mass concentration of 33%, the mixture is fed into a flotation machine, stirring is started for slurry preparation, and the slurry preparation time is 2 minutes. Then, a 0.5% mass concentration of HCl aqueous solution is added to the slurry, the pH value is adjusted to 5.5, and the slurry preparation and stirring are continued for 2 minutes to obtain slurry; S3. Flotation removal: After adding 0.1wt%, 15mg of fulvic acid solution to each liter of ore pulp, add 2wt%, 100mg of collector sodium oleate solution after an interval of 3 minutes. After the reaction is sufficient, aerate and scrape the foam. The flotation foam product obtained is tailings, and the product in the tank is phosphate concentrate.

[0034] Example 2 A method for reverse flotation of phosphate ore to remove magnesium comprises the following steps: S1. Crushing and grinding: Use a jaw crusher to crush and screen calcium-magnesium phosphate ore (chemical composition includes P2O5 21.02%, MgO 9.85%, CaO 41.27%, Al2O3 2.17%, Fe2O3 1.03%, SiO2 4.27%, K2O 0.15%) to obtain powder with a particle size of less than 2 mm. Then add the crushed powder to a ceramic ball mill and grind it until the particle size of the powder is less than 74μm, accounting for 87%, which is phosphate rock powder; S2. Mechanical slurry preparation: Phosphate rock powder is mixed with ultrapure water at room temperature (25°C) to obtain a mixture with a mass concentration of 33%, and the mixture is fed into a flotation machine, and stirring is started for slurry preparation for 2 minutes. Then, a 0.5% mass concentration of HCl aqueous solution is added to the slurry, and the pH value is adjusted to 5.0. The slurry preparation and stirring are continued for 2 minutes to obtain slurry; S3. Flotation removal: After adding 0.1wt%, 30mg of fulvic acid solution to each liter of ore pulp, add 2wt%, 120mg of collector sodium oleate solution after an interval of 3 minutes. After the reaction is sufficient, aerate and scrape the foam. The flotation foam product obtained is tailings, and the product in the tank is phosphate concentrate.

[0035] Comparative Example 1 A method for reverse flotation of phosphate ore to remove magnesium, the other contents are the same as those of Example 1, except that no fulvic acid solution is added in step S3.

[0036] Comparative Example 2 A method for reverse flotation of phosphate ore to remove magnesium, the other contents are the same as those of Example 1, except that in step S3, the fulvic acid solution is replaced by a phosphoric acid solution.

[0037] Comparative Example 3 A method for removing magnesium by reverse flotation of phosphate ore, the other contents of which are the same as those of Example 2, except that no fulvic acid solution is added in step S3.

[0038] Comparative Example 4 A method for reverse flotation of phosphate ore to remove magnesium, the other contents are the same as those of Example 2, except that, in step S3, the fulvic acid solution is replaced by a phosphoric acid solution.

[0039] Test and Evaluation The physical parameters of the phosphate concentrate products obtained in the tanks of Examples 1-2 and Comparative Examples 1-4 were tested, and the results are shown in Table 1.

[0040] Table 1 Phosphate concentrate test results

[0041] In Comparative Examples 1 and 2, when the inhibitor of the present invention is not used or when the conventional inhibitor is used, the P2O5 grade in the phosphate concentrate obtained is significantly lower, while the MgO content is higher, and the P2O5 recovery rate is about 20-27 percentage points lower. In Comparative Examples 3 and 4, when the inhibitor of the present invention is not used or when the conventional inhibitor is used, the P2O5 grade in the phosphate concentrate obtained is significantly lower, while the MgO content is higher, and the P2O5 recovery rate is about 10-24 percentage points lower. This indicates that the reverse flotation of phosphate ore using the flotation inhibitor based on fulvic acid of the present invention can significantly improve the removal effect of calcium and magnesium impurities, thereby improving the grade and recovery rate of the phosphate concentrate.

[0042] The above are only preferred specific implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for removing magnesium from phosphate ore by reverse flotation, characterized in that: The following steps are involved: S1. crushing, screening, grading and grinding calcium-magnesium phosphate ore to obtain phosphate rock powder; S2. After adding water to the phosphate rock powder, the pH value is adjusted to 4.5-9.0 to obtain a slurry; S3. In the slurry, an inhibitor solution and a collector solution are sequentially added to carry out flotation to remove impurities to obtain tailings and phosphate concentrate; The inhibitor solution is a fulvic acid and / or fulvic acid salt solution.

2. The method for reverse flotation removal of magnesium from phosphate rock according to claim 1, characterized in that: In the step S1, in the phosphate rock powder, particles with a particle size of ≤74 μm account for 70-95 wt %.

3. The method for reverse flotation removal of magnesium from phosphate rock according to claim 1, characterized in that: In the step S2, the concentration of the slurry is 20-36wt%.

4. The method for reverse flotation removal of magnesium from phosphate rock according to claim 1, characterized in that: In step S3, the collector includes sodium oleate.

5. The method for reverse flotation and demagnesization of phosphate ore according to claim 1, characterized in that: In step S3, the concentration of the inhibitor solution is 0.01-0.2wt%, and the material-liquid ratio of the inhibitor to the ore slurry is 20-30mg:1L.

6. The method for reverse flotation and magnesium removal of phosphate ore according to claim 1, characterized in that: In step S3, the concentration of the collector solution is 1-4wt%, and the solid-liquid ratio of the collector to the ore slurry is 40-200mg:1L.

7. The method for removing magnesium from phosphate ore by reverse flotation according to claim 1, characterized in that: In step S3, after adding the inhibitor solution, add the collector solution after an interval of 2-4 minutes.

8. The method for removing magnesium from phosphate ore by reverse flotation according to claim 1, characterized in that: The method also includes filtering and drying the tailings.

9. A phosphate concentrate obtained by the method according to any one of claims 1 to 8, characterized in that: In the phosphate concentrate, the P2O5 grade is 34.58-37.89%, and the MgO grade is ≤0.95%.

10. Use of the method according to any one of claims 1 to 8 in the field of phosphate ore separation and purification.

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