Flotation method of low-grade phosphorite

Abstract

The invention discloses a flotation method of low-grade phosphorite, which comprises the following steps: S1, grinding the low-grade phosphorite until the mass ratio of-0.074 mm is greater than 85%, and then mixing pulp; s2, the pH of the ore pulp is adjusted to 8-9, 200-500 g / t of a collecting agent xanthate, 240-300 g / t of an activating agent and 50-80 g / t of a collecting agent hydroximic acid are added for reverse flotation phosphorus extraction and iron removal operation, and iron-removed concentrate is obtained; s3, the pH of the concentrate product obtained in the step S2 is adjusted to be larger than 9.5, sodium silicate with the use amount being 1-2 kg / t and the modulus being 2.8-3 and a mixed collecting agent C1 with the use amount being 0.3-0.5 kg / t are added for first-stage direct flotation, then the mixed collecting agent C1 with the use amount being 1.5-2 kg / t is added for second-stage direct flotation, and dealuminated concentrate is obtained; and S4, the pH value of the concentrate product obtained in the step S3 is adjusted to 4-5, 200-300 g / t of WF-01 is added for reverse flotation, and magnesium-removed concentrate is obtained. The sulphide ore and the oxidized ore in the refractory phosphorite are collected and floated, removal of iron sulfide and iron oxide is achieved, and the quality and the recovery rate of the phosphate concentrate are remarkably improved.

Description

Technical Field

[0001] The invention relates to mineral flotation, in particular to a flotation method for low-grade phosphate ore. Background Art

[0002] Phosphate rock is an important strategic non-metallic mineral resource. With the depletion of high-quality phosphate ore resources, the content of magnesium, aluminum, iron and other impurities in the ore has increased significantly. Simply removing the magnesium impurity is difficult to meet the needs of phosphorus chemical production. Strictly controlling the content of impurities such as iron and aluminum is crucial to achieving the comprehensive utilization of phosphorus resources.

[0003] Sesquioxides are oxides in which the ratio of oxygen to other elements in the chemical formula is 3:2. Sesquioxides in phosphate rock are iron oxide and aluminum oxide. Iron is mainly found in iron minerals such as pyrite (iron sulfide), hematite, and goethite (iron oxide), while aluminum is mainly found in clay minerals such as muscovite, potassium feldspar, and montmorillonite. The increase in the content of sesquioxides in phosphate rock will lead to problems such as the decline in the quality of downstream phosphorus chemical products, scaling of pipelines, and transportation difficulties. Flotation is the most widely used and mature process in the beneficiation of phosphate ore, but the content of sesquioxides in phosphate rock is low, the embedded particle size is fine, and the embedded relationship with other minerals is complex. The enrichment of phosphate resources through conventional flotation reagents and process flows is limited, the amount of reagents used is large, and the interaction between the reagents is difficult to avoid, which directly affects the sorting effect.

[0004] In addition, in pyrite and other sulfide ores, due to the low iron oxide content in the original ore, people have not paid much attention to it. Therefore, people mainly focus on sulfide ores in the flotation process, and focus on positive flotation deironing, that is, by adding a large amount of inhibitors or dispersants in the process of phosphorus flotation to reduce the floating of iron sulfide in the positive flotation process. People rarely use strong iron oxide collectors in the process of phosphate ore flotation deironing. The main iron removal methods include xanthate flotation and positive flotation adding inhibitors. However, in fact, in addition to natural hematite and goethite, pyrite oxidation will also form iron oxide ore, resulting in an increase in iron oxide content. Summary of the invention

[0005] In view of the problems that traditional flotation processes have limited removal of iron impurities in phosphate ore, large amounts of reagents are used, and interactions between reagents are inevitable, the present invention provides a flotation method for low-grade phosphate ore, which achieves the coordinated removal of iron, aluminum and magnesium impurities in phosphate ore and has strong promotion value in the industrial production of complex and difficult-to-select colloidal phosphate ore.

[0006] In order to achieve the above object, the present invention provides a flotation method for low-grade phosphate ore, which comprises the following steps:

[0007] S1. Grind the low-grade phosphate ore to -0.074mm with a mass ratio of >85%, and then prepare the slurry;

[0008] S2, adjusting the pH of the ore pulp to 8-9, adding 200-500 g / t of xanthate collector, 240-300 g / t of activator and 50-80 g / t of hydroxamic acid collector to perform reverse flotation to extract phosphorus and remove iron, and obtain iron-free 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 dispersant and 0.3-0.5 kg / t of mixed collector C1 to carry out first-stage positive flotation, and then adding 1.5-2 kg / t of mixed collector C1 to carry out second-stage positive flotation to obtain dealuminated concentrate;

[0010] S4. The pH value of the concentrate product obtained in step S3 is adjusted to 4-5, and 200-300 g / t WF-01 collector is added to perform reverse flotation to obtain a demagnesized concentrate.

[0011] In the process of iron removal, the above technical solution relies on xanthate collectors and activators to activate pyrite, which enhances the reaction activity of the pyrite surface, thereby promoting further adsorption of the collector, maximizing the collection of pyrite and floating it out with the foam. The collector hydroxamic acid can form a stable heterocyclic chelate with the metal ion iron through complexation, selectively adsorb on the surface of hematite and goethite to form a hydrophobic complex, thereby improving the recovery rate of iron minerals.

[0012] In the dealumination process, fatty acid collectors can form chemical bonds with aluminum metal sites on the mineral surface through their carboxylic acid groups. This chemical adsorption can improve the hydrophobicity of the mineral, thereby promoting the flotation of the mineral; while alcohol collectors contain hydroxyl groups, which can form hydrogen bonds with the hydroxyl groups on the mineral surface, further enhancing the hydrophobicity of the mineral. The combined use of the two surfactants improves the flotation effect through synergistic effects.

[0013] The present invention collects and floats sulfide ores and oxide ores in refractory phosphate ore, realizes the removal of iron sulfide and iron oxide, avoids the interaction of mixed reagents that reduces the effect of reagent action, improves the removal efficiency of iron sulfide and iron oxide, and significantly improves the quality and recovery rate of phosphate concentrate. The present invention is suitable for the coordinated removal of sesquioxides of different types of complex and refractory collophosphate ores, and has good application prospects in the field of clean development and utilization of phosphate resources.

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

[0015] Specifically, in step S1, the slurry concentration is adjusted to be 25-35% by mass.

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

[0017] Further preferably, in step S2, the activating agent is copper sulfate and ammonium sulfate, Cu 2+ It can form stable copper-ammonia complexes such as [Cu(NH3)4]2 with ammonia molecules (NH3) + , which can selectively activate pyrite, the amount of copper sulfate used is 80-100g / t, and the amount of ammonium sulfate used is 160-200g / 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 to 3:2:1.

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

[0020] S2.1, adjust the pH of the slurry to 8-9, add the collector xanthate and the activator in sequence to carry out reverse flotation to remove iron, and obtain the iron-free rough concentrate;

[0021] S2.2, maintaining the pH value of the deironed crude concentrate obtained in step S2.1 at 8-9, adding a collector hydroxamic acid to carry out secondary reverse flotation to extract phosphorus and remove iron, and obtain a deironed concentrate.

[0022] In the above technical solution, iron sulfide and iron oxide are flotated in steps. First, a part of pyrite is floated using a xanthate collector, and then the remaining iron oxide minerals are floated using a hydroxamic acid collector. According to the surface properties of different minerals, the flotation conditions are adjusted in a targeted manner to improve the selectivity of flotation. The step-by-step addition of two collectors can reduce the overall dosage of reagents and 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 processing ores containing multiple iron minerals. This method can improve the overall sorting effect.

[0023] As another preferred embodiment of the present invention, step S2 is: adjusting the pH of the ore pulp to 8-9, adding collector xanthate, activator and collector hydroxamic acid to perform a reverse flotation operation for phosphorus extraction and iron removal to obtain a de-ironified concentrate.

[0024] The xanthate, activator and collector hydroxamic acid are added simultaneously for a reverse flotation. The combined use of xanthate (preferably xanthate) and hydroxamic acid (preferably octyl hydroxamic acid) can produce a synergistic effect under specific pH conditions to enhance the flotation effect of phosphate ore. This synergistic effect is reflected in the fact that the coexistence of hydroxamic acid and xanthate helps to destroy the hydration film on the surface of the mineral, exposing more action sites on the surface of the mineral and increasing the probability of reaction. On the other hand, it is reflected in the co-adsorption of the two collectors on the surface of the mineral, thereby improving the flotation efficiency and selectivity, greatly simplifying the flotation process.

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

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

[0027] Through the above technical solution, the present invention achieves the following beneficial effects:

[0028] 1. The present invention collects and floats sulfide ores and oxide ores in refractory phosphate ore, realizes the removal of iron sulfide and iron oxide, avoids the interaction of mixed reagents that reduces the effect of reagents, improves the removal efficiency of iron sulfide and iron oxide, and significantly improves the quality and recovery rate of phosphate concentrate. It is suitable for the coordinated removal of different types of complex and refractory collophosphate sesquioxides, and has good application prospects in the field of clean development and utilization of phosphate resources.

[0029] 2. In a preferred technical solution of the present invention, the phosphate concentrate obtained by step-by-step dosing flotation meets the material standard for superior wet-process phosphoric acid, and realizes the coordinated removal of iron, aluminum, and magnesium sesquioxides in complex and difficult-to-select phosphate ores. The staged dosing has a higher degree of iron enrichment, a smoother beneficiation process, stable and controllable foam, and low energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a flotation flow chart of phosphate rock in an embodiment of the present invention. DETAILED DESCRIPTION

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

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

[0033] Example 1

[0034] use Figure 1 The specific operation is as follows: crush the Wengfu a-layer phosphate ore, grind it to -0.074mm with a mass fraction of 88% using a ball mill, adjust the slurry concentration to 30% by mass, and then send it to the flotation machine mineralization stirring tank, set the flotation machine spindle speed, flotation aeration volume and scraper speed to 2000r / min, and the flotation aeration volume to 1.2m 3 / h, scraper speed 25r / min, and then flotation. First, sodium carbonate is added to adjust the pH to 8.5, and copper sulfate, ammonium sulfate and xanthate are added in amounts of 200g / t, 80g / t and 200g / t, respectively, for reverse flotation to extract phosphorus and remove iron, and then 50g / t of hydroxamic acid is added, and the bottom product obtained after scraping is deferrization concentrate; then the deferrization concentrate is subjected to two-stage positive flotation, sodium carbonate is used to adjust the pulp pH to 9.8, and sodium silicate with a modulus of 2.8-3 and mixed collector C1 in an amount of 300g / t are added in sequence for a first-stage positive flotation; then mixed collector C1 is added in an amount of 1.5kg / t for a second-stage positive flotation; finally, the dealuminized concentrate obtained by the two positive flotations is subjected to reverse flotation, sulfuric acid is used to adjust the pH to 4-5, and 300g / t of WF-01 reagent is added for reverse flotation, and the final flotation concentrate is left at the bottom of the tank. The final flotation phosphate concentrate was sampled and tested, and the results are shown in Table 1.

[0035] Table 1 Phosphate concentrate test results

[0036]

[0037] From the results in Table 1, it can be seen that the content of Fe2O3 in the iron concentrate and sulfur concentrate obtained by double reverse flotation is relatively high, especially in sulfur concentrate, which reaches 18.46%, while the content of Fe2O3 in the final flotation concentrate is 0.41%, indicating that the stepwise addition of xanthate and hydroxamic acid collectors to double reverse flotation of phosphate ore has a high enrichment degree for 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 material standards for superior wet-process phosphoric acid: P2O5%>32%, R2O3% / P2O5%<10%. The flotation process achieves the coordinated removal of iron, aluminum and magnesium sesquioxides in complex and difficult-to-separate phosphate ores.

[0038] Example 2

[0039] The Wengfu a-layer phosphate ore was crushed and finely ground to -0.074mm with a ball mill, accounting for 90% by mass. The pulp concentration was adjusted to 25% by mass and then sent to the flotation machine mineralization stirring tank. The main shaft speed, flotation aeration volume and scraper speed of the flotation machine were set to 1900r / min, and the flotation aeration volume was 0.1m 3 / h, scraper speed 20r / min, and then flotation. First, sodium carbonate is added to adjust the pH to 9, and copper sulfate, ammonium sulfate, xanthate and octyl hydroxamic acid are added in amounts of 100g / t, 160g / t, 500g / t and 80g / t, respectively, for reverse flotation to extract phosphorus and remove iron. After scraping, the bottom product is the deferrization concentrate; then the deferrization concentrate is subjected to two-stage positive 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 in an amount of 500g / t are added in sequence for a first-stage positive flotation; then the mixed collector C1 is added in an amount of 2kg / t for a second-stage positive flotation; finally, the dealuminized concentrate obtained by the two positive flotations is subjected to reverse flotation, sulfuric acid is used to adjust the pH to 4-5, 200g / t of WF-01 reagent is added for reverse flotation, and the final flotation concentrate is left at the bottom of the tank. The final flotation phosphate concentrate was sampled and tested, and the results are shown in Table 2.

[0040] Table 2 Phosphate concentrate test results

[0041]

[0042] From the results in Table 2, it can be seen that the content of Fe2O3 in the iron concentrate and sulfur concentrate obtained by reverse flotation de-ironization is relatively high, especially in sulfur concentrate, which reaches 19.55%, while the content of Fe2O3 in the final flotation concentrate is 0.61%, indicating that the addition of xanthate and octyl hydroxamic acid collectors to reverse flotate phosphate ore has a high enrichment degree for iron minerals. The final phosphate concentrate grade is 32.33% P2O5, 0.99% MgO, 0.61% Fe2O3, and 1.63% Al2O3. Compared with the original ore, the final phosphate concentrate grade is increased by 8.87%, the recovery rate is 86.01%, and the R2O3 (Fe2O3 + Al2O3) content is 2.24%. All indicators meet the material standards for superior wet-process phosphoric acid: P2O5%>32%, R2O3% / P2O5%<10%. The flotation process achieves the coordinated removal of iron, aluminum and magnesium sesquioxides in complex and difficult-to-separate phosphate ores.

[0043] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0044] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0045] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A flotation method for low-grade phosphate ore, It is characterized in that The steps include: S1. Grind the low-grade phosphate ore to -0.074mm with a mass ratio of >85%, and then prepare the slurry; S2, adjusting the pH of the ore pulp to 8-9, adding 200-500 g / t of xanthate collector, 240-300 g / t of activator and 50-80 g / t of hydroxamic acid collector to perform reverse flotation to extract phosphorus and remove iron, and obtain iron-free concentrate; S3, adjusting the pH of the concentrate product obtained in step S2 to greater than 9.5, adding 1-2 kg / t of dispersant and 0.3-0.5 kg / t of mixed collector C1 to carry out first-stage positive flotation, and then adding 1.5-2 kg / t of mixed collector C1 to carry out second-stage positive flotation to obtain dealuminated concentrate; S4. The pH value of the concentrate product obtained in step S3 is adjusted to 4-5, and 200-300 g / t of WF-01 collector is added for reverse flotation to obtain a demagnesized concentrate.

2. The flotation method according to claim 1, It is characterized in that In step S1, the low-grade phosphate ore contains 2 O 5 The content of MgO is 20-30%, the content of Fe is 2-10%, 2 O 3 The content of Al is 0.3-10%, 2 O 3 The content is 2-15%.

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

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

5. The flotation method according to claim 4, It is characterized in that In step S2, the activators are 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, It is characterized in that In step S2, the mixed collector C1 includes sodium alkyl fatty acid, sodium stearate and n-octanol in a mass ratio of 5 to 3:2:

1.

7. The flotation method according to claim 1, It is characterized in that Step S2 is: S2.1, adjust the pH of the slurry to 8-9, add the collector xanthate and the activator in sequence to carry out reverse flotation to remove iron, and obtain the iron-free rough concentrate; S2.2, maintaining the pH value of the deironed rough concentrate obtained in step S2.1 at 8-9, adding a collector hydroxamic acid to carry out secondary reverse flotation to extract phosphorus and remove iron, and obtain a deironed concentrate.

8. The flotation method according to claim 1, It is characterized in that Step S2 is: adjusting the pH of the ore pulp to 8-9, adding a collector xanthate, an activator and a collector hydroxamic acid to perform a reverse flotation operation to extract phosphorus and remove iron, and obtain a de-ironified concentrate.

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

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

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