Beneficiation method for removing iron, aluminum and magnesium in phosphorite through combination of magnetic separation and flotation

Abstract

The invention relates to the technical field of collophanite beneficiation, and discloses a beneficiation method for removing iron, aluminum and magnesium in phosphorite by combining magnetic separation and flotation, which comprises the following steps: grinding phosphate ore until the content of-0.075 mm is more than 80%, separating iron-containing minerals and aluminum-containing minerals from the phosphate ore by using strong magnetic separation equipment, and separating ore grinding media from associated iron and aluminum of the phosphorite by using weak magnetic separation equipment. And the obtained phosphorite without iron and aluminum minerals is subjected to reverse flotation to remove dolomite, so that low-iron, low-aluminum and low-magnesium high-quality phosphate concentrate, phosphate concentrate with medium iron and aluminum content and high iron ore can be obtained, iron, aluminum and magnesium impurities in the phosphate concentrate are effectively removed, and efficient utilization of all minerals in the phosphorite is achieved. By means of the beneficiation method, the problems that iron and aluminum in phosphorite are high in content and difficult to effectively remove due to depletion of the phosphorite can be effectively solved, and the beneficiation method for efficient impurity removal of the phosphorite is simple in process, low in cost and easy to industrialize.

Description

Technical Field

[0001] The invention relates to the technical field of phosphate ore dressing, and in particular to a method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation. Background Art

[0002] The main impurities in phosphate rock are iron, aluminum, magnesium, etc. In the production of wet phosphoric acid, iron-containing minerals mainly increase acid consumption, and iron also affects the color of phosphoric acid and downstream products; aluminum-containing minerals are prone to form tiny crystals in phosphoric acid production, affecting phosphoric acid filtration and phosphoric acid quality; magnesium-containing carbonate minerals increase acid consumption, and the formed magnesium salts have high solubility in phosphoric acid, affecting the quality of downstream products. Therefore, wet phosphoric acid production urgently needs to remove impurities such as iron, aluminum, and magnesium as much as possible.

[0003] Since the removal of iron and aluminum impurities in phosphoric acid is costly, technically difficult, and difficult to industrialize, it is necessary to remove impurities such as iron and aluminum from the ore supply end.

[0004] For example, patent document CN108273657A discloses a method for combined magnetic-flotation separation of phosphate ore, which is characterized by comprising the following steps: (1) magnetic separation: crushing low-grade phosphate ore containing magnetic iron minerals, grinding it into a particle size of less than 0.074 mm, accounting for 60-70 wt%, adjusting the ore pulp, and then using a strong magnetic separator with a magnetic field strength of 12000±5000GS to remove the magnetic iron minerals in the phosphate ore through a one-roughing and two-sweeping process to obtain a rough concentrate; (2) flotation: adding a regulator to the rough concentrate from which the magnetic iron minerals are removed by strong magnetic separation, and reverse flotation to remove sesquioxides, the process is one roughing, 3-5 sweeping, to obtain a desquioxide concentrate, adding a regulator and a demagnesium collector to the desquioxide concentrate in turn, and reverse flotation to remove magnesium to obtain a phosphate concentrate. However, the steps are complicated and require multiple sweeping.

[0005] Therefore, a method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation is needed to solve the above problems. Summary of the invention

[0006] The purpose of the present invention is to provide a method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation, so as to solve the technical problem that the existing phosphate ore mainly removes magnesium, but has high impurity content such as iron and aluminum, making it difficult to produce high-end phosphate products.

[0007] The scheme of the present invention is:

[0008] A method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation, comprising the following steps:

[0009] S1. After the ore is ground through a grinding process, the ore is ground to -0.075mm and the content is greater than 80%; water is added to dilute the slurry concentration to 5-10%;

[0010] S2, the slurry is subjected to strong magnetic separation by a high gradient magnetic separator, and the magnetic field strength is controlled at 1.5-1.7T to obtain de-iron phosphate concentrate and high iron and aluminum medium and low grade phosphate ore. 2 O 5 Content 19% ~ 24.5%, MgO content 3.8% ~ 8%, Fe 2 O 3 Content 0.6~0.8%, Al 2 O 3 The content is 0.8-1.4%; the P in the high-iron-aluminum medium- and low-grade phosphate ore 2 O 5 Content 10% ~ 15%, MgO content 4.2% ~ 8.4%, Fe 2 O 3 Content 8~10%, Al 2 O 3 Content 2-5%;

[0011] S3, the high iron and aluminum medium and low grade phosphate ore is diluted with water to a concentration of 2-5%, and magnetic separation is performed by a wet magnetic separator, and the magnetic field current is 1-2A to obtain phosphorus-containing iron ore and low iron medium and low grade phosphate ore. 2 O 5 Content less than 5%, Fe 2 O 3 The content is greater than 40%; the P in the low-iron low-grade phosphate ore 2 O 5 Content greater than 15%, Fe 2 O 3 Content less than 3%, Al 2 O 3 Content less than 2%;

[0012] S4, the de-iron phosphate concentrate obtained in step S2 is subjected to conventional reverse flotation to remove carbonate ore and dolomite minerals to obtain P 2 O 5 The content is greater than 30%, the MgO content is less than 0.8%, and the Fe 2 O 3 Content less than 0.6%, Al 2 O 3 High-quality phosphate concentrate with low magnesium, low iron and aluminum content less than 0.8%; used for the production of food-grade phosphoric acid, iron phosphate, lithium iron phosphate and calcium phosphate for feed;

[0013] The low-iron medium-low-grade phosphate ore obtained in step S3 is subjected to conventional reverse flotation to remove carbonate ore production process, and dolomite minerals are removed to obtain phosphate ore. 2 O 5Content 26-28%, MgO content less than 0.8%, Fe 2 O 3 Content less than 1%, Al 2 O 3 Medium-quality phosphate concentrate with a content of less than 1.7% can be used as ore for the production of phosphate fertilizer and yellow phosphorus, etc.

[0014] As a preferred technical solution, the collophanite in S1 is an iron-containing collophanite, in which the iron is mainly limonite, and is a non-magnetic or weakly magnetic mineral; 2 O 5 Content 18%~24%, MgO content 4%~8%, Fe 2 O 3 :0.6~1.7%、Al 2 O 3 Content 1~3%.

[0015] As a preferred technical solution, the number of strong magnetic separation operations in S1 is 1 to 2 times.

[0016] As a preferred technical solution, the method further comprises step S5, reprocessing the phosphorus-containing iron ore obtained in step S3.

[0017] As a preferred technical solution, the S3 phosphorus-containing iron ore is reprocessed or directly used as a raw material and sold as an iron ore resource.

[0018] As a preferred technical solution, the reprocessing is magnetic separation.

[0019] As a preferred technical solution, the Fe of iron ore is obtained by magnetic separation. 2 O 3 Content 45-50%.

[0020] As a preferred technical solution, the grinding media in S1 are steel balls and steel forgings, and the limonite and the steel ball media produced by grinding are mixed and selected through high-gradient strong magnetic separation to achieve separation of phosphate ore and iron minerals.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This method separates phosphate ore from iron minerals by mixing limonite and steel ball media produced by grinding through high-gradient strong magnetic separation; then separates grinding steel ball media from weakly magnetic limonite and aluminum-containing minerals through wet magnetic separation, thus separating and utilizing steel ball media from limonite. Most of the iron and aluminum impurities are removed by magnetic separation, the MER value in phosphate concentrate is reduced, the quality of phosphate concentrate is improved, and the effective utilization of various resources in phosphate ore is achieved.

[0023] The present invention provides a method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation. Since the iron-containing and aluminum-containing minerals in phosphate ore have fine particle sizes, which can only be effectively dissociated at -20 microns, conventional flotation methods cannot effectively remove them. In addition, since the ore particles are relatively fine and have strong mutual adsorption ability, they form agglomerates, flotation entrainment is serious, and the phosphorus loss rate is high. Therefore, strong magnetic separation is used to first separate the iron-containing minerals from phosphorus, and then weak magnetic separation is used to separate the grinding medium from the brown ore, so as to recover the phosphate minerals as much as possible. The present invention is a method for removing impurities from phosphate ore with simple process, low cost and easy industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0025] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0026] Embodiment 1:

[0027] S1, Collophanite P 2 O 5 Content 23.5%, MgO content 4%, Fe 2 O 3 Content 0.8%, Al 2 O 3 The content is 1.0%, and the ore is ground to -0.075mm using a two-stage two-closed ball mill, and the content accounts for 88%; after grinding, the colloidal phosphate P 2 O 5 Content 23.5%, MgO content 4%, Fe 2 O 3 Content 1.0%, Al 2 O 3 Content 1.0%;

[0028] S2, the pulp is diluted with water to a concentration of 8%, and a high gradient strong magnetic separator is used to control the magnetic field intensity to 1.5T to obtain the iron-free phosphate ore (1) P 2 O 5 Content 24%, MgO content 4.2%, Fe 2 O 3 Content 0.4%, Al 2 O 3 Content 0.5%; medium and low grade phosphate ore with high iron and aluminum content (2)P 2 O 5 Content 20%, MgO content 4%, Fe 2 O 3 Content 5%, Al 2 O 3 Content 1.6%;

[0029] S3, dilute the high iron and aluminum medium and low grade phosphate ore (2) with water to a concentration of 2%, use a wet magnetic separator, control the magnetic field current to 1A, and obtain the low iron and low grade phosphate ore (3) containing P 2 O 5 Content 20.5%, MgO content 5.0%, Fe 2 O 3 Content 0.8%, Al 2 O 3 Content 1.4%; (4) P in phosphorus iron ore 2 O 5 Content 4%, MgO content 1%, Fe 2 O 3 Content 45%, Al 2 O 3 Content 1%;

[0030] S4, the conventional reverse flotation process of collophanite is used to remove dolomite minerals from the iron-free phosphate ore (1), and a regulator and a collector are added respectively to obtain P 2 O 5 Content 30.6%, MgO content 0.7%, Fe 2 O 3 Content 0.6%, Al 2 O 3 High quality phosphate concentrate with low magnesium, low iron and aluminum content of 0.7%.

[0031] The conventional reverse flotation process of collophanite is used to remove dolomite minerals from low-iron medium- and low-grade phosphate ore (3), and a regulator and a collector are added to obtain P 2 O 5 Content 28%, MgO content 0.8%, Fe 2 O 3 Content 1%, Al 2 O 3 A medium quality phosphate concentrate with a content of 1.6%.

[0032] The regulator is one of sulfuric acid, phosphoric acid or other inorganic acids; the collector is fatty acid sodium salt.

[0033] The phosphorus-containing iron ore (4) is directly sold as a product.

[0034] Embodiment 2:

[0035] S1, Collophanite P 2 O 5 Content 21%, MgO content 5.5%, Fe 2 O 3 Content 1.0%, Al 2 O3 The content is 1.6%, and the ore is ground to -0.075mm using a two-stage two-closed ball mill, and the content accounts for 88%; after grinding, the colloidal phosphate P 2 O 5 Content 21%, MgO content 5.5%, Fe 2 O 3 Content 1.3%, Al 2 O 3 Content 1.6%;

[0036] S2, the pulp is diluted with water to a concentration of 6%, and a high gradient strong magnetic separator is used to control the magnetic field intensity to 1.5T to obtain the iron-free phosphate ore (1) P 2 O 5 Content 21.6%, MgO content 5.6%, Fe 2 O 3 Content 0.6%, Al 2 O 3 Content 0.6%; medium-low grade phosphate ore with high iron and aluminum content (2)P 2 O 5 Content 17%, MgO content 5.5%, Fe 2 O 3 Content 8%, Al 2 O 3 Content 3%;

[0037] S3, dilute the high iron and aluminum medium and low grade phosphate ore (2) with water to a concentration of 3%, use a wet magnetic separator, control the magnetic field current to 2A, and obtain low iron medium and low grade phosphate ore (3) containing iron phosphate ore P 2 O 5 Content 20%, MgO content 6%, Fe 2 O 3 Content 0.9%, Al 2 O 3 Content 1.5%; iron phosphate ore (4) P 2 O 5 Content 3%, MgO content 1.5%, Fe 2 O 3 Content 48%, Al 2 O 3 Content 1.2%;

[0038] S4, the production process of removing dolomite minerals from the iron-free phosphate ore (1) by using the conventional reverse flotation production process of collophanite, adding a regulator and a collector respectively, to obtain P 2 O 5 Content 30%, MgO content 0.6%, Fe 2 O 3 Content 0.7%, Al 2 O 3High-quality phosphate concentrate with a content of 0.8%;

[0039] The conventional reverse flotation process of collophanite is used to remove dolomite minerals from low-iron medium- and low-grade phosphate ore (3), and a regulator and a collector are added to obtain P 2 O 5 Content 28%, MgO content 0.8%, Fe 2 O 3 Content 1.2%, Al 2 O 3 A medium quality phosphate concentrate with a content of 1.7%.

[0040] The regulator is one of sulfuric acid, phosphoric acid or other inorganic acids; the collector is fatty acid sodium salt.

[0041] The phosphorus-containing iron ore (4) is directly sold as a product.

[0042] Embodiment 3:

[0043] S1, Collophanite P 2 O 5 Content 20%, MgO content 6.5%, Fe 2 O 3 Content 1.4%, Al 2 O 3 The content is 2%, and the ore is ground to -0.075mm using a two-stage two-closed ball mill, and the content accounts for 90%; after grinding, the colloidal phosphate P 2 O 5 Content 20%, MgO content 6.5%, Fe 2 O 3 Content 1.7%, Al 2 O 3 Content 2%;

[0044] S2, the pulp is diluted with water to a concentration of 5%, and a high gradient strong magnetic separator is used to control the magnetic field intensity to 1.7T to obtain the iron-free phosphate ore (1) P 2 O 5 Content 20.8%, MgO content 6.8%, Fe 2 O 3 Content 0.7%, Al 2 O 3 Content 0.8%; medium-low grade phosphate ore with high iron and aluminum content (2)P 2 O 5 Content 15%, MgO content 5%, Fe 2 O 3 Content 10%, Al 2 O 3 Content 3.8%;

[0045] S3, dilute the high iron and aluminum medium and low grade phosphate ore (2) with water to a concentration of 2%, use a wet magnetic separator, control the magnetic field current to 2A, and obtain low iron and low grade phosphate ore (3) P 2 O 5 Content 18%, MgO content 7%, Fe 2 O 3 Content 1.0%, Al 2 O 3 Content 1.7%; iron phosphate ore (4) P 2 O 5 Content 4%, MgO content 1.2%, Fe 2 O 3 Content 46%, Al 2 O 3 Content 2.0%;

[0046] The conventional reverse flotation process of collophanite is used to remove dolomite from the iron-free phosphate ore (1), and a regulator and a collector are added to obtain P 2 O 5 Content 30%, MgO content 0.7%, Fe 2 O 3 Content 0.8%, Al 2 O 3 High quality phosphate concentrate with 0.9% content.

[0047] The conventional reverse flotation process of collophanite is used to remove dolomite minerals from low-iron medium- and low-grade phosphate ore (3), and a regulator and a collector are added to obtain P 2 O 5 Content 27%, MgO content 0.9%, Fe 2 O 3 Content 1.2%, Al 2 O 3 A medium quality phosphate concentrate with a content of 1.9%.

[0048] The regulator is one of sulfuric acid, phosphoric acid or other inorganic acids; the collector is fatty acid sodium salt.

[0049] Product (4) is sold directly as a product.

[0050] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation, characterized in that: The following steps are involved: S1. After the ore is ground through a grinding process, the ore is ground to -0.075mm and the content is greater than 80%; water is added to dilute the slurry concentration to 5-10%; S2, the slurry is subjected to strong magnetic separation by a high gradient magnetic separator, and the magnetic field strength is controlled at 1.5-1.7T to obtain de-iron phosphate concentrate and high-iron and low-grade phosphate ore, respectively. The de-iron phosphate concentrate has a P2O5 content of 19%-24.5%, a MgO content of 3.8%-8%, a Fe2O3 content of 0.6-0.8%, and an Al2O3 content of 0.8-1.4%; the high-iron and low-grade phosphate ore has a P2O5 content of 10%-15%, a MgO content of 4.2%-8.4%, a Fe2O3 content of 8-10%, and an Al2O3 content of 2-5%; S3, the high-iron and aluminum-containing medium- and low-grade phosphate ore is diluted with water to a concentration of 2-5%, and subjected to magnetic separation by a wet magnetic separator, with a magnetic field current of 1-2A, to obtain phosphorus-containing iron ore and low-iron medium- and low-grade phosphate ore, wherein the phosphorus-containing iron ore has a P2O5 content of less than 5% and a Fe2O3 content of greater than 40%; the low-iron medium- and low-grade phosphate ore has a P2O5 content of greater than 15%, a Fe2O3 content of less than 3%, and an Al2O3 content of less than 2%; S4, using the conventional reverse flotation process to remove carbonate ore from the de-iron phosphate concentrate obtained in step S2 to remove dolomite minerals, thereby obtaining a low-magnesium, low-iron-aluminum, high-quality phosphate concentrate having a P2O5 content greater than 30%, a MgO content less than 0.8%, a Fe2O3 content less than 0.6%, and an Al2O3 content less than 0.8%; The low-iron, medium-grade phosphate ore obtained in step S3 is subjected to conventional reverse flotation to remove carbonate ore and dolomite minerals to obtain a medium-quality phosphate concentrate with a P2O5 content of 26-28%, a MgO content of less than 0.8%, a Fe2O3 content of less than 1%, and an Al2O3 content of less than 1.7%.

2. The method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation as claimed in claim 1, characterized in that: The collophanite in S1 is an iron-containing collophanite, in which the iron is mainly limonite, and is a non-magnetic or weakly magnetic mineral; the iron-containing collophanite contains 18% to 24% P2O5, 4% to 8% MgO, 0.6 to 1.7% Fe2O3, and 1 to 3% Al2O3.

3. The method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation as claimed in claim 1, characterized in that: The number of strong magnetic separation operations in S1 is 1 to 2 times.

4. The method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation as claimed in claim 1, characterized in that: The method further comprises step S5: reprocessing the phosphorus-containing iron ore obtained in step S3.

5. A method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation as claimed in claim 4, characterized in that: The reprocessing is magnetic separation.

6. A method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation as claimed in claim 5, characterized in that: Through re-magnetic separation, the Fe2O3 content of the iron ore is 45-50%.

7. The method for removing iron, aluminum and magnesium from phosphate ore by combining magnetic separation and flotation as claimed in claim 1, characterized in that: The grinding media in S1 are steel balls and steel forgings. The limonite and the steel ball media produced by grinding are mixed and selected through high-gradient strong magnetic separation to achieve separation of phosphate ore and iron minerals.

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