Methods for separating low-grade apatite from calcite

Abstract

This application provides a method for separating low-grade apatite from calcite in the beneficiation process, belonging to the field of heavy metal purification in industrial wastewater. The method involves first subjecting the low-grade phosphate rock to magnetic separation to remove iron, reducing the interference of this gangue on subsequent processes; then performing centrifugal pre-enrichment to remove most of the calcite and other argillaceous gangue, further reducing the interference of this gangue on the subsequent apatite flotation; finally, the obtained centrifuged rough concentrate is subjected to flotation separation, and by adding appropriate amounts of a specially formulated inhibitor CD-P and collector CK to enhance the inhibition of calcite and the collecting effect of apatite, respectively, the effective separation of calcite and apatite is achieved, ultimately realizing the goal of efficient recovery of phosphate concentrate.

Description

Technical Field

[0001] This invention relates to the field of ore flotation technology, specifically to a method for separating low-grade apatite from calcite. Background Technology

[0002] Phosphorus is a non-renewable resource that plays a vital role in the national economy and agricultural production, and is widely used in agriculture, medicine, and chemical industries. Phosphate rock, as the main source of phosphorus, is an important raw material for the phosphorus industry, and one of the valuable minerals in phosphate rock is apatite. With the continuous increase in mineral resource mining, high-grade apatite resources are becoming increasingly scarce, while low-grade apatite is difficult to sort due to its similarity to carbonate minerals.

[0003] Low-grade apatite-type phosphate deposits in my country are associated with minerals such as calcite, magnetite, mica, and feldspar, mainly distributed in Hebei, Liaoning, and Shaanxi provinces. The phosphate ore grade ranges from 1% to 3%. Current production practices generally involve first magnetically separating iron, then magnetically separating the tailings, followed by a direct flotation process to recover apatite. For processing these ultra-low-grade phosphate ores, the direct flotation process requires low levels of carbonate minerals such as calcite and dolomite, and coarse-grained apatite. Because apatite and carbonate minerals have similar physicochemical properties, carbonate minerals often accumulate in apatite concentrate. If the carbonate mineral content in the ore is too high, or the particle size is too fine (over 70% -75μm), it is often difficult to obtain qualified phosphate concentrate using direct flotation. Using a combination of direct and reverse flotation processes results in high reagent costs and low ore value, making it uneconomical. Therefore, the vast majority of this calcite-containing ultrafine low-grade apatite resource has not been effectively utilized, resulting in a waste of phosphorus resources.

[0004] In view of this, it is necessary to design a beneficiation and separation method for 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 art, this application provides a method for separating low-grade apatite and calcite in beneficiation, aiming to solve the existing technical problem that it is not easy to separate carbonate minerals from phosphate resources in low-grade phosphate ore containing high-grade carbonate minerals.

[0006] This application provides a method for separating low-grade apatite from calcite in mineral processing, including the following steps:

[0007] S1. After preparing the target iron tailings into a slurry, magnetic separation is performed to obtain magnetically separated tailings;

[0008] S2. After concentrating the magnetic separation tailings, centrifuge pre-enrichment is performed to obtain centrifuged rough concentrate;

[0009] S3. The centrifuged rough concentrate is subjected to one roughing and one scavenging to obtain rough concentrate and tailings; the reagents added during the first roughing include: inhibitor CD-P, water glass, and collector CK; the reagents added during the first scavenging include collector CK.

[0010] The inhibitor CD-P is composed of modified starch, sodium alginate, and sodium polyacrylate.

[0011] The collector CK is a compound of sulfurized fatty acid soap and oxidized paraffin soap in a mass ratio of 9:1.

[0012] S4. The rough concentrate is subjected to several fine-tuning processes in sequence to finally obtain phosphate concentrate.

[0013] In the technical solution of this application embodiment, low-grade phosphate rock is first subjected to magnetic separation to remove iron, followed by centrifugal pre-enrichment. The resulting centrifuged rough concentrate is then subjected to flotation separation. By adding appropriate amounts of a specially formulated inhibitor CD-P and collector CK to enhance the inhibition of calcite and the collection of apatite, respectively, effective separation of calcite and apatite is achieved, ultimately realizing the goal of efficient recovery of phosphate concentrate. The specially formulated collector CK exhibits increased selectivity compared to traditional fatty acid collectors. Furthermore, the foam produced by this collector CK becomes brittle and easily breaks, thus reducing the entrainment and flotation of fine mud, which is beneficial for improving the grade of the final phosphate concentrate.

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

[0015] In this embodiment, the prepared specific inhibitor CD-P has a high selective inhibitory effect on carbonate minerals. This is because CK-P is mainly adsorbed on the surface of apatite through hydrogen bonding, while the adsorption on calcite is due to chemical bonding. Compared with hydrogen bonding, CK-P has a stronger adsorption on calcite than 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 sulfurized fatty acid soap is as follows: Tar oil and concentrated sulfuric acid are reacted at 20-30°C for 1 hour at a mass ratio of 5:1, and then alkali is added to neutralize to pH 8.

[0017] In some embodiments, during the initial coarse selection in step S3, 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, during step S3, when performing a single scavenging, the amount of collector CK added is 100-150 g / t.

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

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

[0021] In some embodiments, step S4 includes a first selection, a second selection, and a third selection.

[0022] In some embodiments, the selection time in step S4 is 2 to 3 minutes each time.

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

[0024] In some embodiments, in step S2, the concentration of the concentrated magnetic separation 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 this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0027] Figure 1 This is a flowchart of the beneficiation and separation method for low-grade apatite and calcite in the embodiments of this application. Detailed Implementation

[0028] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0030] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0033] In existing technologies, direct flotation is mainly used to recover apatite from low-grade apatite-type phosphate rock. However, this method requires low content of carbonate minerals such as calcite and dolomite in the ore, as well as coarse apatite particle size. On the other hand, using a combination of direct and reverse flotation to recover apatite involves high reagent costs, making it uneconomical for recovering low-content ore. Therefore, it is crucial to provide a separation method that can efficiently recover phosphate concentrate from low-grade apatite-type phosphate rock containing high carbonate mineral content while controlling reagent costs.

[0034] To address the aforementioned technical problems, this application provides a method for separating low-grade apatite from calcite in beneficiation. The method involves first subjecting the low-grade phosphate ore to magnetic separation to remove iron, followed by centrifugal pre-enrichment. The resulting centrifuged rough concentrate is then subjected to flotation separation. Furthermore, by adding appropriate amounts of a specially formulated inhibitor CD-P and collector CK, the inhibition of calcite and the collection of apatite are enhanced, respectively, thereby achieving effective separation of calcite and apatite and ensuring the effective recovery of the subsequent phosphate concentrate.

[0035] This application provides a method for separating low-grade apatite from calcite in mineral processing, including the following steps:

[0036] S1. After preparing the target iron tailings into a slurry, magnetic separation is performed to remove magnetic gangue and obtain magnetic tailings.

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

[0038] S2. After concentrating the magnetic separation tailings, centrifuge pre-enrichment is performed to obtain centrifuged rough concentrate and centrifuged tailings.

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

[0040] S3. The centrifuged rough concentrate is subjected to a first roughing and a first scavenging of apatite to obtain rough concentrate and tailings.

[0041] The reagents added during a roughing process include: inhibitor CD-P, water glass, and collector CK; the reagents added during a scavenging process include collector CK.

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

[0043] In step S3, during the first roughing process, 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.

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

[0045] In step S3, the time for one coarse selection is 2-3 minutes; the time for one sweep selection is 2-3 minutes.

[0046] S4. The rough concentrate is subjected to several fine-tuning processes in sequence to finally obtain phosphate concentrate; the several fine-tuning processes include primary fine-tuning, secondary fine-tuning and tertiary fine-tuning.

[0047] In some embodiments, the selection time in step S4 is 2 to 3 minutes each time.

[0048] The process involves first magnetically separating and de-ironizing low-grade phosphate rock, followed by centrifugal pre-enrichment. The resulting centrifuged rough concentrate is then subjected to flotation separation. By adding appropriate amounts of a specially formulated inhibitor CD-P and collector CK to enhance the inhibition of calcite and the collection of apatite, respectively, effective separation of calcite and apatite is achieved, ultimately leading to the efficient recovery of phosphate concentrate. The specially formulated collector CK exhibits increased selectivity compared to traditional fatty acid collectors (talc soap, oleic acid soap). Furthermore, the foam produced by this collector CK becomes brittle and easily breaks, reducing the entrainment of fine mud and contributing to a higher grade of the final phosphate concentrate.

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

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

[0051] In the technical solution of this application embodiment, low-grade phosphate rock is first subjected to magnetic separation to remove iron, followed by centrifugal pre-enrichment. The resulting centrifuged rough concentrate is then subjected to flotation separation. By adding appropriate amounts of a specially formulated inhibitor CD-P and collector CK, the inhibition of calcite and the collection of apatite are enhanced, respectively, thus achieving effective separation of calcite and apatite and ultimately achieving the goal of efficient recovery of phosphate concentrate. The specially formulated collector CK has increased selectivity compared to traditional fatty acid collectors. Furthermore, the foam produced by this collector CK becomes brittle and easily breaks, thereby reducing the entrainment and floatation of fine mud, which is beneficial to improving the grade of the final phosphate concentrate.

[0052] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0053] Example 1

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

[0055] S1. After preparing the target iron tailings into a slurry, magnetic separation is performed to remove magnetic gangue and obtain magnetic tailings.

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

[0057] S2. The magnetic separation tailings are concentrated and then pre-enriched by centrifugation to obtain centrifuged rough concentrate and centrifuged tailings; the concentration of the concentrated magnetic separation tailings is 30%; the parameters for centrifugation pre-enrichment include: centrifugal force of 90g (g is the acceleration due to gravity) and backwash water flow rate of 3L / min.

[0058] S3. The centrifuged rough concentrate is subjected to a first roughing and a first scavenging of apatite to obtain a rough concentrate and tailings; the reagents added during the first roughing include: inhibitor CD-P, water glass, and collector CK; the reagents added during the first scavenging include collector CK.

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

[0060] During the first roughing process, the amount of inhibitor CD-P added was 200 g / t, the amount of water glass added was 200 g / t, and the amount of collector CK added was 300 g / t.

[0061] When performing one scavenging operation, the amount of collector CK added is 100 g / t;

[0062] In step S3, the time for one roughing is 2 minutes; the time for one scavenging is 2 minutes; in step S4, the roughing concentrate is subjected to one fine cleaning (2 minutes), two fine cleaning (2 minutes), and three fine cleaning (2 minutes) in sequence to finally obtain phosphate concentrate, wherein the P2O5 grade in the phosphate concentrate is 32.02% and the phosphorus recovery rate is 70.90%.

[0063] Comparative Example 1

[0064] Comparative Example 1 provides a method for separating low-grade apatite from calcite in beneficiation. The difference from Example 1 is that magnetic separation for iron removal is not performed in step S1. The remaining steps are the same as in Example 1 and will not be repeated here.

[0065] Comparative Example 2

[0066] Comparative Example 2 provides a method for separating low-grade apatite from calcite in beneficiation. The difference from Example 1 is that centrifugal pre-concentration is not performed in step S2. The remaining steps are the same as in Example 1 and will not be repeated here.

[0067] Comparative Examples 3-5

[0068] Comparative Examples 3-5 each provide a method for separating low-grade apatite from calcite in beneficiation. The difference between Comparative Example 3 and Example 1 lies in the reagents 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; and the reagents added in Comparative Example 5 are sodium polyacrylate, water glass, and collector CK. The remaining steps are the same as in Example 1 and will not be repeated here.

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

[0070] Examples 2-3 and Comparative Examples 6-7 each provide a method for separating low-grade apatite from calcite in beneficiation. The difference from Example 1 lies in the different proportions of the components in the inhibitor CD-P added in step S3. In Comparative Example 6, the ratio of modified starch, sodium alginate, and polyacrylic acid in the inhibitor CD-P is 4:1:3; in Example 2, the ratio is 4:2:3; in Example 3, the ratio is 4:5:3; and in Comparative Example 7, the ratio is 4:6:3. The remaining steps are the same as in Example 1 and will not be repeated here.

[0071] Comparative Examples 8-9

[0072] Comparative Examples 8 and 9 respectively provide a method for separating low-grade apatite from calcite in beneficiation. The difference between Comparative Example 8 and Example 1 lies in the reagents added in step S3. The reagents added in Comparative Example 8 are the inhibitor CD-P, water glass, and tall oil soap; the reagents added in Comparative Example 9 are the inhibitor CD-P, water glass, and oleic acid soap. The remaining steps are the same as in Example 1 and will not be repeated here.

[0073] Comparative Examples 10-11

[0074] Comparative Examples 10 and 11 respectively provide a method for separating low-grade apatite from calcite in beneficiation. The difference from Example 1 lies in the different proportions of the components in the collector CK added in step S3. In Comparative Example 10, the ratio of sulfurized fatty acid soap to oxidized paraffin soap in the collector CK is 9:2; in Comparative Example 11, the ratio of sulfurized fatty acid soap to oxidized paraffin soap in the collector CK is 9:0. The remaining steps are the same as in Example 1 and will not be repeated here.

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

[0076] Table 1. Results of low-grade apatite and calcite beneficiation separation in Examples 1-3 and Comparative Examples 1-11.

[0077]

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

[0079] As shown in Table 1, only when the low-grade apatite and calcite beneficiation separation method provided in this application is adopted can the P2O5 grade in the obtained phosphate concentrate 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 separation method provided by this invention first performs magnetic separation to remove iron from the low-grade phosphate ore, reducing the interference of this gangue on subsequent processes; then, centrifugal pre-enrichment is performed to remove most of the calcite and other argillaceous gangue, reducing the interference of this argillaceous gangue on the subsequent apatite flotation; subsequently, the obtained centrifuged rough concentrate is subjected to flotation separation, and by adding appropriate amounts (significantly reducing costs compared to traditional reagents) of a specially formulated inhibitor CD-P and collector CK to enhance the inhibition of calcite and the collection of apatite, respectively, the effective separation of calcite and apatite is achieved, ultimately achieving the goal of efficient recovery of phosphate concentrate. The inhibitor CD-P used has a high selective inhibition effect on carbonates, etc.; the specially formulated collector CK has increased selectivity compared to traditional fatty acids, and the foam of this collector CK becomes brittle and easily breaks, thus reducing the entrainment and flotation of fine mud, which is conducive to improving the grade of the final phosphate concentrate.

[0081] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for separating low-grade apatite from calcite in beneficiation, characterized in that, Includes the following steps: S1. After preparing the target iron tailings into a slurry, magnetic separation is performed to obtain magnetically separated tailings; S2. After concentrating the magnetic separation tailings, centrifuge pre-enrichment is performed to obtain centrifuged rough concentrate; S3. The centrifuged rough concentrate is subjected to one roughing and one scavenging to obtain rough concentrate and tailings; the reagents added during the first roughing include: inhibitor CD-P, water glass, and collector CK; the reagents added during the first scavenging include collector CK. The inhibitor CD-P is composed of modified starch, sodium alginate, and sodium polyacrylate. The collector CK is a compound of sulfurized fatty acid soap and oxidized paraffin soap in a mass ratio of 9:

1. S4. The rough concentrate is subjected to several fine-tuning processes in sequence to finally obtain phosphate concentrate.

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

4. The method for separating low-grade apatite and calcite ore according to claim 3, characterized in that, In step S3, during the first coarse selection, 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.

5. The method for separating low-grade apatite and calcite ore according to claim 4, characterized in that, In step S3, during one scavenging operation, the amount of collector CK added is 100-150 g / t.

6. The method for separating low-grade apatite and calcite ore according to claim 5, characterized in that, In step S3, the time for one coarse selection is 2 to 3 minutes; In step S3, the time for one scan is 2 to 3 minutes.

7. The method for separating low-grade apatite and calcite in beneficiation according to claim 1, characterized in that, In step S4, the selection process includes a first selection, a second selection, and a third selection.

8. The method for separating low-grade apatite and calcite ore according to claim 7, characterized in that, In step S4, the selection time for each step is 2 to 3 minutes.

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

10. The method for separating low-grade apatite and calcite ore according to claim 2, characterized in that, In step S2, the concentration of the concentrated magnetic separation 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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