Mineral separation method for low-grade apatite and calcite

Abstract

The invention provides a beneficiation separation method for low-grade apatite and calcite, and belongs to the field of purification of heavy metals in industrial wastewater. Low-grade phosphate ore is firstly subjected to magnetic separation to remove iron, so that the interference of the gangue on the subsequent process is reduced; then centrifugal pre-enrichment is carried out, most of muddy gangue such as calcite is removed, and interference of the muddy gangue on apatite flotation in the follow-up process is reduced; and then the obtained centrifugal rough concentrate is subjected to a flotation separation process, and a proper amount of specially-made inhibitor CD-P and a proper amount of specially-made collecting agent CK are added to strengthen the inhibition effect of calcite and the collecting effect of apatite respectively, so that effective separation of calcite and apatite can be achieved, and finally the purpose of efficiently recycling phosphate concentrate is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of ore flotation, and in particular to a method for separating low-grade apatite and calcite from the ore. Background Art

[0002] Phosphorus is a non-renewable resource that plays an important role in the national economy and agricultural production. It is widely used in agriculture, medicine, chemical industry and other industries. As the main source of phosphorus, phosphate rock is an important raw material for the phosphorus industry. One of the valuable minerals in phosphate rock is apatite. With the continuous increase in the mining of mineral resources, high-grade apatite resources are becoming less and less, while low-grade apatite is difficult to separate because of its similar selectivity to carbonate minerals.

[0003] Low-grade apatite-type phosphate ore in my country is associated with calcite, magnetite, mica, feldspar and other minerals. It is mainly distributed in Hebei, Liaoning, Shaanxi and other places. The grade of phosphate ore is between 1% and 3%. In current production practice, iron is usually separated magnetically first, and then the tailings are separated magnetically. Then, apatite is recovered by direct flotation process. To treat this type of ultra-low-grade phosphate ore, the direct flotation process requires that the content of carbonate minerals such as calcite and dolomite in the ore is low, and the apatite is embedded in a coarse particle size. Due to the similar physical and chemical properties of apatite and carbonate minerals, carbonate minerals are often enriched in apatite concentrate. Once the content of carbonate minerals in the ore is too high, or the particle size is fine (-75μm accounts for more than 70%), it is often difficult to obtain qualified phosphate concentrate by direct flotation. If the direct-reverse flotation process is used, the cost of the reagents used is high, the value of the ore is low, and there is no economic benefit. Therefore, most of this part of ultrafine low-grade apatite resources containing calcite has not been effectively utilized, resulting in a waste of phosphorus resources.

[0004] In view of this, it is necessary to design a method for separating low-grade apatite and calcite to solve the above problems. Summary of the invention

[0005] In view of the technical problems existing in the background technology, the present application provides a method for separating low-grade apatite and calcite, aiming to solve the existing technical problem that it is difficult to separate carbonate minerals from phosphate resources in low-grade phosphate ore containing high-grade carbonate minerals.

[0006] The present application provides a method for separation of low-grade apatite and calcite, comprising the following steps:

[0007] S1, preparing the target iron ore tailings into ore pulp and then performing magnetic separation to obtain magnetic separation tailings;

[0008] S2, concentrating the magnetic separation tailings and performing centrifugal pre-enrichment to obtain a centrifugal coarse concentrate;

[0009] S3, subjecting the centrifugal coarse concentrate to a roughing selection and a scavenging selection to obtain a roughing concentrate and tailings; the reagents added during the roughing selection include: inhibitor CD-P, water glass, collector CK; the reagents added during the scavenging selection include collector CK;

[0010] The inhibitor CD-P is a mixture of modified starch, sodium alginate, and sodium polyacrylate;

[0011] Collector CK is compounded by sulfurized fatty acid soap and oxidized paraffin soap in a mass ratio of 9:1;

[0012] S4, the rougher concentrate is subjected to several rounds of cleaning in sequence to finally obtain phosphate concentrate.

[0013] In the technical solution of the embodiment of the present application, the low-grade phosphate ore is first subjected to magnetic separation and iron removal and then to centrifugal pre-enrichment, and then the obtained centrifugal coarse concentrate is subjected to a flotation separation process, and by adding an appropriate amount of a special inhibitor CD-P and a collector CK to strengthen the inhibition of calcite and the collection of apatite respectively, the effective separation of calcite and apatite can be achieved, and the purpose of efficiently recovering phosphate concentrate is finally achieved. Among them, the special collector CK used has a higher selectivity than the traditional fatty acid, and the foam of this collector CK becomes brittle and easy to break, thus reducing the entrainment and floating of fine mud, which is conducive to the improvement of the grade of the phosphate concentrate finally obtained.

[0014] In some embodiments, in the inhibitor CD-P, the mass ratio of modified starch, sodium alginate, and sodium polyacrylate is 4:2 to 5:3.

[0015] In this embodiment, the prepared specific inhibitor CD-P has a highly selective inhibitory effect on carbonate minerals. This is because CK-P is mainly adsorbed on the surface of apatite through hydrogen bonds, while the adsorption on calcite is due to chemical bonding. Compared with the hydrogen bond form, the adsorption of CK-P on calcite is stronger than that on apatite, so that the inhibitor CD-P can preferentially adsorb on calcite during the flotation process of the ore, thereby separating apatite from calcite.

[0016] In some embodiments, the preparation process of sulphurized fatty acid soap is as follows: tall oil and concentrated sulfuric acid are reacted at a mass ratio of 5:1 at 20-30°C for 1 hour, and then alkali is added to neutralize to a pH of 8.

[0017] In some embodiments, in step S3, when a rough selection is performed, the amount of inhibitor CD-P added is 200-500 g / t, the amount of water glass added is 200-500 g / t, and the amount of collector CK added is 300-400 g / t.

[0018] In some embodiments, in step S3, when performing a scan, the amount of collector CK added is 100-150 g / t.

[0019] In some embodiments, in step S3, the time for performing a rough selection is 2 to 3 minutes;

[0020] In step S3, the time for one scanning is 2 to 3 minutes.

[0021] In some embodiments, in step S4, the several times of selection include one time selection, two times selection, and three times selection.

[0022] In some embodiments, in step S4, each selection process takes 2 to 3 minutes.

[0023] In some embodiments, in step S1, the particle size of the iron ore tailings is -75 μm, accounting for more than 80%; the concentration of the prepared slurry is 20-25%; and the magnetic field strength for magnetic separation is 2000-3000 GS.

[0024] In some embodiments, in step S2, the concentration of the concentrated magnetic tailings is 30-35%; the parameters for centrifugal pre-enrichment include: centrifugal force of 90g-120g, and backwash water flow rate of 3-4L / min.

[0025] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 The present invention is a flow chart of the method for separating low-grade apatite and calcite in the embodiment of the present application. DETAILED DESCRIPTION

[0028] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0030] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0033] In the prior art, the direct flotation process is mainly used to recover apatite from low-grade apatite phosphate ore. However, this method requires that the content of carbonate minerals such as calcite and dolomite in the ore is low, and the apatite embedding particle size is also required to be coarse; and when the direct-reverse flotation process is used to recover apatite, the cost of the reagents used is high, and there is no economic benefit for recovering low-content ores. Therefore, it is particularly important to provide a separation method that can efficiently recover the phosphate concentrate in low-grade apatite phosphate ore containing a high content of carbonate minerals while controlling the cost of reagents.

[0034] In order to solve the above-mentioned technical problems, the present application provides a method for the separation of low-grade apatite and calcite, wherein the low-grade phosphate ore is first subjected to magnetic separation and iron removal, and then centrifugal pre-enrichment, and then the obtained centrifugal rough concentrate is subjected to a flotation separation process, and by adding appropriate amounts of a special inhibitor CD-P and collector CK, the inhibition of calcite and the collection of apatite are respectively enhanced, so as to achieve effective separation of calcite and apatite, thereby ensuring the effective recovery of the subsequent phosphate concentrate.

[0035] The present application provides a method for separation of low-grade apatite and calcite, comprising the following steps:

[0036] S1. The target iron ore tailings are prepared into ore pulp and then subjected to magnetic separation to remove magnetic gangue to obtain magnetic separation tailings;

[0037] The particle size of the iron ore tailings is -75 μm, accounting for more than 80%; the concentration of the prepared slurry is 20-25%; the magnetic field strength for magnetic separation is 2000-3000 GS;

[0038] S2, concentrating the magnetic separation tailings and performing centrifugal pre-enrichment to obtain centrifugal coarse concentrate and centrifugal tailings;

[0039] The concentration of the concentrated magnetic tailings is 30-35%; the parameters for centrifugal pre-enrichment include: centrifugal force of 90g-120g (g is gravity acceleration), backwash water flow rate of 3-4L / min;

[0040] S3, subjecting the centrifugal rough concentrate to apatite roughing and scavenging to obtain a roughing concentrate and tailings;

[0041] The reagents added during a roughing selection include: inhibitor CD-P, water glass, collector CK; the reagents added during a sweeping selection include collector CK;

[0042] The inhibitor CD-P is prepared by mixing modified starch, sodium alginate and sodium polyacrylate; the preparation process of the collector CK is as follows: tall oil and concentrated sulfuric acid are placed in a reactor at 20-30° C. in a mass ratio of 5:1, reacted for 1 hour, and then 40% sodium hydroxide solution is added to adjust the pH to 8 to obtain sulfide fatty acid soap, and then the sulfide fatty acid soap is compounded with oxidized paraffin soap in a mass ratio of 9:1;

[0043] In step S3, when a rough selection is performed, the addition amount of inhibitor CD-P is 200-500 g / t, the addition amount of water glass is 200-500 g / t, and the addition amount of collector CK is 300-400 g / t;

[0044] When performing a sweep, the amount of collector CK added is 100-150 g / t;

[0045] In step S3, the time for a rough selection is 2 to 3 minutes; the time for a sweep selection is 2 to 3 minutes;

[0046] S4, the rougher concentrate is subjected to several rounds of concentration in sequence to finally obtain a phosphate concentrate; the several rounds of concentration include primary concentration, secondary concentration, and tertiary concentration.

[0047] In some embodiments, in step S4, each selection process takes 2 to 3 minutes.

[0048] Among them, the low-grade phosphate ore is first subjected to magnetic separation and iron removal and then centrifugal pre-enrichment, and then the obtained centrifugal coarse concentrate is subjected to flotation separation process, and by adding appropriate amounts of special inhibitor CD-P and collector CK to strengthen the inhibition of calcite and the collection of apatite respectively, the effective separation of calcite and apatite can be achieved, and the purpose of efficient recovery of phosphate concentrate is finally achieved. Among them, the special collector CK used has higher selectivity than traditional fatty acids (tall oil soap, oleic acid soap), and the foam of this collector CK becomes brittle and easy to break, thus reducing the entrainment and floating of fine mud, which is conducive to improving the grade of the final phosphate concentrate.

[0049] Furthermore, in some embodiments, in the inhibitor CD-P, the mass ratio of modified starch, sodium alginate, and sodium polyacrylate is 4:2 to 5:3.

[0050] The prepared specific inhibitor CD-P has a highly selective inhibitory effect on carbonate minerals. This is based on the fact that CK-P is mainly adsorbed on the surface of apatite through hydrogen bonds, while the adsorption on calcite is due to chemical bonding. Compared with the hydrogen bond form, the adsorption of CK-P on calcite is stronger than that on apatite, so that the inhibitor CD-P can preferentially adsorb on calcite during the flotation process of the ore, thereby separating apatite from calcite.

[0051] In the technical solution of the embodiment of the present application, the low-grade phosphate ore is first subjected to magnetic separation and iron removal and then centrifugal pre-enrichment, and then the obtained centrifugal coarse concentrate is subjected to flotation separation process, and by adding appropriate amounts of special inhibitor CD-P and collector CK to strengthen the inhibition of calcite and the collection of apatite respectively, the effective separation of calcite and apatite can be achieved, and the purpose of efficient recovery of phosphate concentrate is finally achieved. Among them, the special collector CK used has higher selectivity than traditional fatty acids, and the foam of this collector CK becomes brittle and easy to break, thus reducing the entrainment and floating of fine mud, which is conducive to the improvement of the grade of the phosphate concentrate finally obtained.

[0052] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. If specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be obtained commercially.

[0053] Example 1

[0054] Example 1 provides a method for separation of low-grade apatite and calcite, comprising the following steps:

[0055] S1. The target iron ore tailings are prepared into ore pulp and then subjected to magnetic separation to remove magnetic gangue to obtain magnetic separation tailings;

[0056] The P2O5 grade in the iron ore tailings is 6.01%, the CaCO3 content is 11.52%, and the Fe content is 9.80%; the tailings particle size -200 mesh accounts for 80%; the concentration of the slurry is 20%; the magnetic field strength for magnetic separation is 3000GS;

[0057] S2, after concentrating the magnetic tailings, perform centrifugal pre-enrichment to obtain centrifugal coarse concentrate and centrifugal tailings; the concentration of the concentrated magnetic tailings is 30%; the parameters for centrifugal pre-enrichment include: centrifugal force of 90g (g is gravity acceleration), backwash water flow rate of 3L / min;

[0058] S3, subjecting the centrifugal rough concentrate to apatite primary roughing and primary scavenging to obtain a roughing concentrate and tailings; the reagents added during the primary roughing include: inhibitor CD-P, water glass, collector CK; the reagents added during the primary scavenging include collector CK;

[0059] The inhibitor CD-P is prepared by mixing modified starch, sodium alginate and sodium polyacrylate in a mass ratio of 4:3:3; the collector CK is prepared by mixing tall oil and concentrated sulfuric acid in a mass ratio of 5:1, reacting in a reactor at 30°C for 1 hour, and then adding 40% sodium hydroxide solution to neutralize to pH 8 to obtain sulfide fatty acid soap, and then compounding the sulfide fatty acid soap with oxidized paraffin soap in a mass ratio of 9:1;

[0060] When performing a roughing operation, the addition amount of inhibitor CD-P is 200g / t, the addition amount of water glass is 200g / t, and the addition amount of collector CK is 300g / t;

[0061] When performing a sweep, the amount of collector CK added is 100g / t;

[0062] In step S3, the time for a roughing selection is 2 minutes; the time for a scavenging selection is 2 minutes; S4, the roughing concentrate is sequentially subjected to a first concentration (2 minutes), a second concentration (2 minutes), and a third concentration (2 minutes), to finally obtain a phosphate concentrate, wherein the grade of P2O5 in the phosphate concentrate is 32.02%, and the recovery rate of phosphorus is 70.90%.

[0063] Comparative Example 1

[0064] Comparative Example 1 provides a method for separation of low-grade apatite and calcite, which differs from Example 1 in that magnetic separation and iron removal are not performed in step S1. The remaining steps are consistent with Example 1 and are not described in detail here.

[0065] Comparative Example 2

[0066] Comparative Example 2 provides a method for separation of low-grade apatite and calcite, which differs from Example 1 in that no centrifugal pre-enrichment is performed in step S2. The remaining steps are consistent with Example 1 and are not described in detail here.

[0067] Comparative Examples 3 to 5

[0068] Comparative Examples 3 to 5 respectively provide a method for beneficiating and separating low-grade apatite and calcite, which differs from Example 1 in that different reagents are added in step S3. The reagents added in Comparative Example 3 are modified starch, water glass, and collector CK; the reagents added in Comparative Example 4 are sodium alginate, water glass, and collector CK; the reagents added in Comparative Example 5 are sodium polyacrylate, water glass, and collector CK. The remaining steps are consistent with Example 1 and are not repeated here.

[0069] Examples 2-3 and Comparative Examples 6-7

[0070] Examples 2 to 3 and comparative examples 6 to 7 respectively provide a method for the separation of low-grade apatite and calcite, which differs from Example 1 in that the ratios of the components in the inhibitor CD-P added in step S3 are different. The ratio of modified starch, sodium alginate, and polyacrylic acid in the inhibitor CD-P added in comparative example 6 is 4:1:3; the ratio of modified starch, sodium alginate, and polyacrylic acid in the inhibitor CD-P added in Example 2 is 4:2:3; the ratio of modified starch, sodium alginate, and polyacrylic acid in the inhibitor CD-P added in Example 3 is 4:5:3; the ratio of modified starch, sodium alginate, and polyacrylic acid in the inhibitor CD-P added in comparative example 7 is 4:6:3. The remaining steps are consistent with those in Example 1 and will not be repeated here.

[0071] Comparative Examples 8 to 9

[0072] Comparative Examples 8 to 9 respectively provide a method for beneficiating and separating low-grade apatite and calcite, which differs from Example 1 in that different reagents are added in step S3. The reagents added in Comparative Example 8 are inhibitor CD-P, water glass, and tall oil soap; the reagents added in Comparative Example 9 are inhibitor CD-P, water glass, and oleic acid soap. The remaining steps are consistent with Example 1 and are not repeated here.

[0073] Comparative Examples 10-11

[0074] Comparative Examples 10 to 11 respectively provide a method for the separation of low-grade apatite and calcite, which differs from Example 1 in that the ratios of the components in the collector CK added in step S3 are different. The ratio of sulfide fatty acid soap: oxidized paraffin soap in the collector CK added in Comparative Example 10 is 9:2; the ratio of sulfide fatty acid soap: oxidized paraffin soap in the collector CK added in Comparative Example 11 is 9:0. The remaining steps are consistent with Example 1 and will not be repeated here.

[0075] The specific flotation results are shown in Table 1.

[0076] Table 1 Separation results of low-grade apatite and calcite in Examples 1 to 3 and Comparative Examples 1 to 11

[0077]

[0078] Note: Evaluation of mineral processing indicators: First, the grade of phosphate concentrate must reach more than 30% qualified products, and secondly, the recovery rate should be considered.

[0079] It can be seen from Table 1 that when and only when the low-grade apatite and calcite beneficiation and separation method provided in the present application is adopted, the P2O5 grade in the obtained phosphate concentrate can be ensured to reach more than 30% while the phosphorus recovery rate can reach more than 70.90%.

[0080] In summary, the low-grade apatite and calcite beneficiation and separation method provided by the present invention first carries out magnetic separation and iron removal on low-grade phosphate ore to reduce the interference of this part of gangue with subsequent processes; then centrifugal pre-enrichment is carried out to remove most of the calcite and other mud gangue, reducing the interference of this part of mud gangue with the subsequent flotation of apatite; then the obtained centrifugal coarse concentrate is subjected to flotation separation process, and by adding appropriate amounts (compared with traditional agents, the cost investment is greatly reduced) of special inhibitor CD-P and collector CK to strengthen the inhibition of calcite and the collection of apatite respectively, the effective separation of calcite and apatite can be achieved, and the purpose of efficiently recovering phosphate concentrate is finally achieved. Among them, the inhibitor CD-P used has a higher selective inhibitory effect on carbonates and the like; the special collector CK used has a higher selectivity than traditional fatty acids, and the foam of this collector CK becomes brittle and easy to break, thus reducing the entrainment and floating of fine mud, which is conducive to the improvement of the grade of the phosphate concentrate finally obtained.

[0081] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for separating low-grade apatite and calcite, characterized in that: The following steps are involved: S1, preparing the target iron ore tailings into ore pulp and then performing magnetic separation to obtain magnetic separation tailings; S2, concentrating the magnetic separation tailings and performing centrifugal pre-enrichment to obtain a centrifugal coarse concentrate; S3, subjecting the centrifugal coarse concentrate to a roughing selection and a scavenging selection to obtain a roughing concentrate and tailings; the reagents added during the roughing selection include: inhibitor CD-P, water glass, collector CK; the reagents added during the scavenging selection include collector CK; The inhibitor CD-P is a mixture of modified starch, sodium alginate, and sodium polyacrylate; Collector CK is compounded by sulfurized fatty acid soap and oxidized paraffin soap in a mass ratio of 9:1; S4, the rougher concentrate is subjected to several rounds of cleaning in sequence to finally obtain phosphate concentrate.

2. The method for separation of low-grade apatite and calcite according to claim 1, characterized in that: In the inhibitor CD-P, the mass ratio of modified starch, sodium alginate and sodium polyacrylate is 4:2 to 5:

3.

3. The method for separation of low-grade apatite and calcite according to claim 2, characterized in that: The preparation process of sulfide fatty acid soap is as follows: tall oil and concentrated sulfuric acid are reacted at 20-30°C for 1 hour in a mass ratio of 5:1, and then alkali is added to neutralize to pH 8.

4. The method for separation of low-grade apatite and calcite according to claim 3, characterized in that: In step S3, when a rough selection is performed, the addition amount of the inhibitor CD-P is 200-500 g / t, the addition amount of the water glass is 200-500 g / t, and the addition amount of the collector CK is 300-400 g / t.

5. The method for separation of low-grade apatite and calcite according to claim 4, characterized in that: In step S3, when performing a sweep, the amount of collector CK added is 100-150 g / t.

6. The method for separation of low-grade apatite and calcite according to claim 5, characterized in that: In step S3, the time for a rough selection is 2 to 3 minutes; In step S3, the time for one scanning is 2 to 3 minutes.

7. The method for separation of low-grade apatite and calcite according to claim 1, characterized in that: In step S4, the several times of selection include one time selection, two times selection and three times selection.

8. The method for separation of low-grade apatite and calcite according to claim 7, characterized in that: In step S4, each selection process takes 2 to 3 minutes.

9. The method for beneficiating and separating low-grade apatite and calcite according to claim 1, characterized in that: In step S1, the particle size of the iron ore tailings is -75 μm, accounting for more than 80%; the concentration of the prepared slurry is 20-25%; and the magnetic field strength for magnetic separation is 2000-3000 GS.

10. The method for separation of low-grade apatite and calcite according to claim 2, characterized in that: In step S2, the concentration of the concentrated magnetic tailings is 30-35%; The parameters for centrifugal pre-enrichment include: centrifugal force of 90g to 120g, and backwash water flow rate of 3 to 4L / min.

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