A method for the flotation of low-grade phosphate ores

Abstract

The application discloses a flotation method of low-grade phosphate ore, which comprises the following steps: S1, grinding the low-grade phosphate ore to a mass ratio of -0.074 mm of more than 85%, and then performing slurry adjustment; S2, adjusting the pH of the slurry to 8-9, adding 200-500 g / t of a collector xanthate, 240-300 g / t of an activator and 50-80 g / t of a collector hydroxamic acid to perform reverse flotation for phosphorus extraction and iron removal, and obtaining iron-removed concentrate; S3, adjusting the pH of the concentrate product obtained in the step S2 to more than 9.5, adding 1-2 kg / t of sodium silicate with a modulus of 2.8-3, and adding 0.3-0.5 kg / t of a mixed collector C1 to perform one-stage positive flotation, and then adding 1.5-2 kg / t of the mixed collector C1 to perform two-stage positive flotation, and obtaining aluminum-removed concentrate; and S4, adjusting the pH of the concentrate product obtained in the step S3 to 4-5, adding 200-300 g / t of WF-01 to perform reverse flotation, and obtaining magnesium-removed concentrate. The sulfide ore and the oxidized ore in the refractory phosphate ore are collected and floated, the removal of the ferric sulfide and the ferric oxide is realized, and the quality and the recovery rate of the phosphate concentrate are significantly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to mineral flotation, in particular, to a flotation method of low-grade phosphate rock. BACKGROUND

[0002] Phosphate rock is an important strategic non-metallic mineral resources, with the depletion of high-quality phosphate rock resources, the content of magnesium, aluminum, iron and other impurities in the ore is significantly increased, it is difficult to meet the needs of phosphorus chemical production by simply removing magnesium impurities, and it is essential to strictly control the content of impurities such as iron and aluminum to realize the comprehensive utilization of phosphate resources.

[0003] The sesquioxide is an oxide with a ratio of oxygen to other elements in the chemical formula of 3:2, and the sesquioxide in phosphate rock is iron oxide and aluminum oxide. Iron mainly exists in iron minerals such as pyrite (iron sulfide), hematite and goethite (iron oxide), and aluminum mainly exists in clay minerals such as muscovite, potassium feldspar and montmorillonite. The increase of the content of sesquioxide in phosphate rock will lead to problems such as quality decline of downstream phosphorus chemical products, pipe fouling and transportation difficulty. Flotation is the most widely used and mature process in the beneficiation process of phosphate rock, but the content of sesquioxide in phosphate rock is low, the embedded particle size is fine, and the embedded relationship with other minerals is complex. The enrichment degree of phosphate rock resources is limited by the conventional flotation reagent system and process flow, the dosage of reagents is large, and the interaction between reagents is difficult to avoid, which directly affects the separation effect.

[0004] In addition, in pyrite and other sulfide ores, due to the low content of iron oxide in the raw ore, people have not paid enough attention to it, so people mainly focus on the flotation of sulfide ore in the process of removing iron, and the main attention is concentrated on the positive flotation of iron, that is, by adding a large amount of depressant or dispersant in the flotation of phosphorus, the flotation of sulfide iron in the positive flotation process is reduced. People rarely use strong iron oxide collectors in the process of removing iron from phosphate rock, and the main iron removal methods include xanthate flotation and positive flotation with depressant. However, in fact, in addition to natural hematite and goethite, the oxidation of pyrite will also form iron oxide, resulting in an increase in the content of iron oxide. SUMMARY

[0005] In view of the problems that the amount of iron impurities removed by the traditional flotation process is limited, the dosage of reagents is large, and the interaction between reagents is inevitable, the present application provides a flotation method of low-grade phosphate rock, which realizes the simultaneous removal of iron, aluminum and magnesium impurities in phosphate rock, and has strong popularization value in the industrial production of complex and refractory collophanite.

[0006] In order to achieve the above purpose, the present application provides a flotation method of low-grade phosphate rock, which comprises the following steps:

[0007] S1, grinding the low-grade phosphate ore to a mass fraction of -0.074 mm of > 85%, and then performing slurry conditioning;

[0008] S2, adjusting the pH of the slurry to 8-9, adding 200-500 g / t of the collector xanthate, 240-300 g / t of the activator, and 50-80 g / t of the collector hydroxamic acid to perform reverse flotation for phosphorus removal and iron removal, and obtaining a de-ironed concentrate;

[0009] S3, adjusting the pH of the concentrate product obtained in step S2 to greater than 9.5, adding 1-2 kg / t of the dispersant, and adding 0.3-0.5 kg / t of the mixed collector C1 to perform one-stage positive flotation, and then adding 1.5-2 kg / t of the mixed collector C1 to perform two-stage positive flotation, and obtaining a de-aluminum concentrate;

[0010] S4, adjusting the pH of the concentrate product obtained in step S3 to 4-5, adding 200-300 g / t of the collector WF-01 to perform reverse flotation, and obtaining a de-magnesium concentrate.

[0011] In the de-ironing process, the xanthate collector and the activator are used to activate the pyrite, thereby enhancing the reactivity of the surface of the pyrite, promoting the further adsorption of the collector, and maximizing the collection of the pyrite to float out with the foam. The hydroxamic acid collector can form a stable heterocyclic chelate with the metal ion iron through complexation, selectively adsorbing on the surface of hematite and goethite, and forming a hydrophobic complex, thereby improving the recovery rate of the iron ore.

[0012] In the de-aluminum process, the fatty acid collector can form a chemical bond with the aluminum metal site on the surface of the mineral through its carboxyl group, and this chemical adsorption can improve the hydrophobicity of the mineral, thereby promoting the flotation of the mineral. The alcohol collector contains a hydroxyl group, which can form a hydrogen bond with the hydroxyl group on the surface of the mineral, further enhancing the hydrophobicity of the mineral. The combined use of the two surface active agents improves the flotation effect through synergistic effect.

[0013] The present application collects and floats the sulfide ore and the oxidized ore in the refractory phosphate ore, realizes the removal of the iron sulfide and the iron oxide, avoids the interaction of the mixed reagents, reduces the effect of the reagents, improves the removal efficiency of the iron sulfide and the iron oxide, significantly improves the quality and the recovery rate of the phosphate concentrate, is suitable for the cooperative removal of different types of complex and refractory collophane sesquioxide, and has a good application prospect in the field of clean development and utilization of phosphate resources.

[0014] Specifically, in step S1, the grade of P2O5 in the low-grade phosphate ore is 20-30%, the content of MgO is 2-10%, the content of Fe2O3 is 0.3-10%, and the content of Al2O3 is 2-15%.

[0015] Specifically, in step S1, the pulp concentration is 25-35% by mass.

[0016] Preferably, in step S2, the xanthate is one or more of sodium butyl xanthate, sodium ethyl xanthate and Z200, the activator is a copper salt and an ammonium salt, and the hydroxamic acid is one or more of octyl hydroxamic acid, benzyl hydroxamic acid and sodium salt thereof.

[0017] Further preferably, in step S2, the activator is copper sulfate and ammonium sulfate, Cu 2+ Ammonia molecules (NH3) can form stable copper ammonia complexes such as [Cu(NH3)4]2 + , which can selectively activate pyrite, the amount of copper sulfate is 80-100 g / t, and the amount of ammonium sulfate is 160-200 g / t.

[0018] Specifically, in step S2, the mixed collector C1 includes sodium alkyl fatty acid, sodium stearate and n-octanol in a mass ratio of 5-3:2:1.

[0019] As a preferred embodiment of the present application, step S2 is:

[0020] S2.1, adjust the pH of the ore pulp to 8-9, sequentially add the collectors xanthate and activator to perform one-stage reverse flotation for iron removal, and obtain a crude iron-removed concentrate;

[0021] S2.2, maintain the pH of the crude iron-removed concentrate obtained in step S2.1 at 8-9, add the collector hydroxamic acid to perform two-stage reverse flotation for phosphorus removal and iron removal, and obtain an iron-removed concentrate.

[0022] In the above technical solution, iron sulfide and iron oxide are floated in steps, a part of pyrite is first floated using xanthate collector, and the remaining oxidized iron minerals are then floated using hydroxamic acid collector. According to the surface properties of different minerals, the flotation conditions are adjusted accordingly, thereby improving the selectivity of flotation. The stepwise addition of two collectors can reduce the overall reagent consumption, avoid the cost increase and environmental problems that may be caused by excessive use of a single collector. At the same time, it can better adapt to the flotation needs of different minerals, especially when dealing with ores containing multiple iron minerals, this method can improve the overall separation effect.

[0023] As another preferred embodiment of the present application, step S2 is: adjust the pH of the ore pulp to 8-9, add the collectors xanthate, activator and hydroxamic acid to perform one-stage reverse flotation for phosphorus removal and iron removal, and obtain an iron-removed concentrate.

[0024] The xanthate, the activator and the collector hydroxamic acid are simultaneously added to carry out the once reverse flotation, and the combination of the xanthate (preferably xanthate) and the hydroxamic acid (preferably octyl hydroxamic acid) can produce a synergistic effect under a specific pH condition, and the flotation effect on the phosphate rock is enhanced. The synergistic effect is embodied in that the coexistence of the hydroxamic acid and the xanthate can help to destroy the hydration film on the mineral surface to expose more active sites on the mineral surface, and increase the probability of reaction, and the synergistic effect is also embodied in that the two collectors can be co-adsorbed on the mineral surface, so that the flotation efficiency and selectivity are improved, and the flotation process is greatly simplified.

[0025] Preferably, in the step S3, the dispersant is sodium silicate with a modulus of 2.8-3, carboxymethyl cellulose or sodium hexametaphosphate, and the function is to keep the fine particles in a dispersed state to improve the flotation efficiency.

[0026] Preferably, the rotation speed of the main shaft of the flotation machine is 1900-2000 r / min, the air charge of the flotation is 0.1-1.2 m 3 / h, and the rotation speed of the scraper is 20-25 r / min.

[0027] Through the above technical scheme, the present application has the following beneficial effects:

[0028] 1. The present application can realize the removal of sulfide and oxidized ore in the refractory phosphate ore, remove the iron sulfide and oxidized iron, avoid the interaction of mixed reagents, reduce the effect of reagents, improve the removal efficiency of iron sulfide and oxidized iron, significantly improve the quality and recovery rate of phosphate concentrate, and is suitable for the synergistic removal of different types of complex and refractory collophanite sesquioxide, and has good application prospect in the field of clean development and utilization of phosphate resources.

[0029] 2. In one preferred technical scheme of the present application, the phosphate concentrate obtained by stepwise addition of reagents meets the standard of wet-process phosphoric acid premium material, and realizes the synergistic removal of iron, aluminum and magnesium sesquioxide in the complex and refractory phosphate ore. The stepwise addition of reagents has a higher enrichment degree of iron, and the beneficiation process is more smooth, the foam is stable and controllable, and the energy consumption is low. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is the flotation process diagram of the phosphate ore in the embodiment of the present application. DETAILED DESCRIPTION

[0031] The specific embodiments of the present application are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0032] The following examples are processed from Guizhou Wengfu a layer phosphate ore, with P2O5 content of 23.60%, MgO content of 2.44%, Fe2O3 content of 2.51%, and Al2O3 content of 4.41%.

[0033] Example 1

[0034] use Figure 1 The process flow is shown below. Specifically, the phosphate ore from layer A of Wengfu is crushed and finely ground to -0.074mm (88% by mass) using a ball mill. The pulp concentration is adjusted to 30% by mass before being fed into the mineralization mixing tank of the flotation machine. The flotation machine spindle speed, flotation aeration rate, and scraper speed are set to 2000 r / min, and the flotation aeration rate is 1.2 m³ / min. 3 The scraper speed is 25 r / min, and then flotation is carried out. First, sodium carbonate is added to adjust the pH to 8.5. Copper sulfate, ammonium sulfate and xanthate are added in sequence at dosages of 200 g / t, 80 g / t and 200 g / t respectively for reverse flotation to remove phosphorus and iron. Then, 50 g / t of hydroxamic acid is added. After skimming, the bottom product of the tank is the de-ironized concentrate. Then, the de-ironized concentrate is subjected to two-stage direct flotation. Sodium carbonate is used to adjust the pulp pH to 9.8. Sodium silicate with a modulus of 2.8-3 and mixed collector C1 at a dosage of 300 g / t are added in sequence for the first stage of direct flotation. Then, mixed collector C1 at a dosage of 1.5 kg / t is added for the second stage of direct flotation. Finally, the dealuminized concentrate obtained from the two direct flotations is subjected to reverse flotation. Sulfuric acid is used to adjust the pH to 4-5. 300 g / t of WF-01 reagent is added for reverse flotation. The product remaining at the bottom of the tank is the final flotation concentrate. The final flotation phosphate concentrate samples were taken and analyzed, and the results are shown in Table 1.

[0035] Table 1. Results of Phosphate Concentrate Analysis

[0036]

[0037] Table 1 shows that the Fe2O3 content in both the iron concentrate and sulfur concentrate obtained from double-reverse flotation for iron removal is relatively high, especially in the sulfur concentrate where the content reaches 18.46%, while the Fe2O3 content in the final flotation concentrate is only 0.41%. This indicates that the addition of xanthate and hydroxamic acid collectors in stages for double-reverse flotation of phosphate rock results in a high degree of enrichment of iron minerals. The final phosphate concentrate grade is 33.65% P2O5, 1.11% MgO, 0.41% Fe2O3, and 1.53% Al2O3. Compared with the original ore, the final phosphate concentrate grade is increased by 10.05%, the recovery rate is 86.00%, and the R2O3 (Fe2O3+Al2O3) content is 1.94%. All indicators meet the standards for high-grade wet-process phosphate feedstock: P2O5% > 32%, R2O3% / P2O5% < 10%. The flotation process enabled the synergistic removal of iron, aluminum, and magnesium sesquioxides from complex and difficult-to-process phosphate rock.

[0038] Example 2

[0039] The vat-fu a layer phosphate rock is crushed, and is finely ground to 90% by mass of -0.074 mm by using a ball mill, and after adjusting the pulp concentration to 25% by mass, is sent to a flotation machine mineralization stirring tank, the main shaft rotation speed of the flotation machine, the flotation air charge and the scraper rotation speed are set to 1900 r / min, the flotation air charge is 0.1 m 3 / h, the scraper rotation speed is 20 r / min, and then flotation is carried out. First, sodium carbonate is added to adjust the pH to 9, and then copper sulfate, ammonium sulfate, xanthate and octyl hydroxamic acid are added in sequence, with the dosages being 100 g / t, 160 g / t, 500 g / t and 80 g / t, respectively, to carry out the reverse flotation phosphorus removal and iron removal operation, and after scraping and foaming, the tank bottom product is obtained as the iron-removed concentrate; then the iron-removed concentrate is subjected to two-stage positive flotation, sodium carbonate is used to adjust the pulp pH to 9.8, and then sodium silicate with a modulus of 2.8-3 and the mixed collector C1 with a dosage of 500 g / t are added in sequence to carry out the first-stage positive flotation; the mixed collector C1 with a dosage of 2 kg / t is further added to carry out the second-stage positive flotation; finally, the aluminum-removed concentrate obtained by the two-stage positive flotation is subjected to reverse flotation, sulfuric acid is used to adjust the pH to 4-5, and then the WF-01 agent with a dosage of 200 g / t is added to carry out the reverse flotation, and the final flotation concentrate is obtained as the concentrate remaining in the tank bottom. The final flotation phosphate concentrate is sampled and tested, and the results are shown in Table 2.

[0040] Table 2 Test results of the phosphate concentrate

[0041]

[0042] It can be seen from the results in Table 2 that the Fe2O3 content in the iron concentrate and the sulfur concentrate obtained by the reverse flotation is relatively high, and in particular, the Fe2O3 content in the sulfur concentrate reaches 19.55%, while the Fe2O3 content in the final flotation concentrate is 0.61%, which indicates that the reverse flotation of the phosphate rock by simultaneously adding the xanthate and the octyl hydroxamic acid collector has a high enrichment degree of the iron minerals. The final phosphate concentrate has a P2O5 content of 32.33%, a MgO content of 0.99%, a Fe2O3 content of 0.61% and an Al2O3 content of 1.63%, and compared with the raw ore, the grade of the final phosphate concentrate is increased by 8.87%, the recovery rate is 86.01%, the R2O3 (Fe2O3 + Al2O3) content is 2.24%, and all the indexes meet the standard of the excellent wet-process phosphoric acid raw material: P2O5% > 32%, R2O3% / P2O5% < 10%. The simultaneous removal of the iron, aluminum and magnesium sesquioxide in the complex and difficult-to-process phosphate rock is realized through the flotation process.

[0043] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0044] It should be further noted that each of the various technical features described in the above embodiments can be combined with any other technical features in any suitable manner, and the present application shall be deemed to disclose all possible combinations thereof, without causing unnecessary repetition.

[0045] Furthermore, any combination of the various embodiments of the present application can be made, as long as it does not deviate from the spirit of the present application, and it shall be deemed to be disclosed by the present application.

Claims

1. A flotation method of low-grade phosphate ores, characterized in that, The method comprises the following steps: S1, grinding the low-grade phosphate ore to a mass fraction of -0.074 mm of >85%, and then performing slurry conditioning; S2, adjusting the pH of the ore slurry to 8-9, adding 200-500 g / t of collector xanthate, 240-300 g / t of activator, and 50-80 g / t of collector hydroxamic acid to perform reverse flotation for phosphorus extraction and iron removal, and obtaining a de-iron concentrate; S3, adjusting the pH of the concentrate product obtained in step S2 to greater than 9.5, adding a dispersant in an amount of 1-2 kg / t, and adding a mixed collector C1 in an amount of 0.3-0.5 kg / t to perform one-stage positive flotation, and then adding the mixed collector C1 in an amount of 1.5-2 kg / t to perform two-stage positive flotation, and obtaining a de-aluminum concentrate; S4, adjusting the pH of the concentrate product obtained in step S3 to 4-5, adding 200-300 g / t of WF-01 collector to perform reverse flotation, and obtaining a de-magnesium concentrate.

2. The flotation method according to claim 1, characterized in that, In step S1, the low-grade phosphate ore has a P2O5 grade of 20-30%, a MgO content of 2-10%, an Fe2O3 content of 0.3-10%, and an Al2O3 content of 2-15%.

3. The flotation method according to claim 1, characterized in that, In step S1, the slurry conditioning concentration is 25-35% by mass fraction.

4. The flotation method according to claim 1, characterized in that, In step S2, the xanthate is one or more of sodium butyl xanthate, sodium ethyl xanthate, and Z200, the activator is a copper salt and an ammonium salt, and the hydroxamic acid is one or more of octyl isoxazoline, benzyl hydroxamic acid, and a sodium salt thereof.

5. The flotation method according to claim 4, characterized in that, In step S2, the activator is copper sulfate and ammonium sulfate, the amount of copper sulfate is 80-100 g / t, and the amount of ammonium sulfate is 160-200 g / t.

6. The flotation method according to claim 1, characterized in that, In step S3, the mixed collector C1 comprises sodium alkyl fatty acid, sodium stearate, and n-octanol in a mass ratio of 5-3:2:

1.

7. The flotation method according to claim 1, characterized by, Step S2 is: S2.1, adjusting the pH of the ore slurry to 8-9, sequentially adding the collector xanthate and the activator to perform one-stage reverse flotation for iron removal, and obtaining a de-iron rough concentrate; S2.2, maintaining the pH of the de-iron rough concentrate obtained in step S2.1 at 8-9, adding the collector hydroxamic acid to perform two-stage reverse flotation for phosphorus extraction and iron removal, and obtaining a de-iron concentrate.

8. The flotation method according to claim 1, characterized by, Step S2 is: adjusting the pH of the ore slurry to 8-9, adding the collector xanthate, the activator, and the collector hydroxamic acid to perform one-stage reverse flotation for phosphorus extraction and iron removal, and obtaining a de-iron concentrate.

9. The flotation method according to claim 1, characterized in that, In step S3, the dispersant is sodium silicate, carboxymethyl cellulose, or sodium hexametaphosphate with a modulus of 2.8-3.

10. The flotation method according to any one of claims 1 to 9, characterized in that, The rotation speed of the main shaft of the flotation machine is 1900-2000 r / min, the air charge of the flotation is 0.1-1.2 m 3 / h, and the rotation speed of the scraper is 20-25 r / min.

Images