Beneficiation method for removing iron and aluminum in reverse flotation magnesium-removed phosphate concentrate and reducing MER through combination of magnetic flotation and beneficiation method for removing iron and aluminum in reverse flotation magnesium-removed phosphate concentrate

Abstract

The invention relates to the technical field of collophanite beneficiation, and discloses a beneficiation method for removing iron and aluminum in reverse flotation magnesium-removed phosphate concentrate and reducing MER through combination of magnetic flotation, dolomite in phosphate ore is removed through reverse flotation operation, the magnesium-removed phosphate concentrate is obtained, high-intensity magnetic separation equipment is used for separating ore grinding media and minerals containing iron and aluminum from the phosphate ore, and the magnesium-removed phosphate concentrate is obtained. The low-iron aluminum-magnesium high-quality phosphate concentrate is obtained; and separating the ore grinding medium from iron and aluminum associated with the phosphorite by using low-intensity magnetic separation equipment to obtain iron minerals and medium-grade phosphate concentrate. Effective separation and utilization of the phosphate concentrate and iron-containing and aluminum-containing minerals are achieved, and the quality of the phosphate concentrate and the additional value of subsequent phosphorus series products are improved. Through the beneficiation method, the problems that iron and aluminum in the phosphate ore are high in content and difficult to effectively remove can be effectively solved, and the beneficiation method for efficiently removing impurities from the phosphate ore 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 ore dressing method for removing iron and aluminum from reverse-floatation demagnesized phosphate concentrate and reducing MER by combining magnetic flotation separation. Background Art

[0002] The main impurities in phosphate rock are iron, aluminum, magnesium and silicon. As the impurity content of Fe, Al and Mg increases, the density and viscosity of wet phosphoric acid increase linearly, which correspondingly reduces the decomposition rate of phosphate rock and the filtration capacity of phosphoric acid slurry. The magnesium content of phosphate rock in my country is very high. When decomposed by acid, most of the MgO becomes magnesium phosphate and enters the phosphoric acid solution, which deteriorates the crystallization process of CaSO·2H2O, reduces the filtration capacity, and the decomposition rate and washing rate also decrease. As the wet phosphoric acid is concentrated, impurities such as magnesium salts will gradually precipitate, and the viscosity will increase sharply, and the fluidity will deteriorate, making it difficult to produce commercial grade phosphoric acid with ω(P2O5)=54%.

[0003] Phosphate rock generally contains ω(Al2O3)=0.2%~3.0%. When the content is too high, it forms a complex with phosphate and becomes flocculated, increasing the viscosity of phosphoric acid and making it difficult to filter. 70%~90% of Al2O3 in phosphate rock is decomposed to form precipitates or dissolved in phosphoric acid.

[0004] Phosphate rock generally contains ω(Fe2O3)=0.1%~2.0%, which forms phosphate or phosphate complex with phosphoric acid, becomes precipitate or dissolves in phosphoric acid to increase the viscosity of phosphoric acid. 60%~90% of Fe2O3 in phosphate rock will be decomposed into phosphoric acid.

[0005] These impurities not only increase the production cost and difficulty in the production of wet phosphoric acid, but also often result in unqualified product quality. Therefore, wet phosphoric acid production urgently needs to remove impurities such as iron, aluminum, and magnesium as much as possible. Due to the high cost and technical difficulty of removing iron and aluminum impurities in phosphoric acid, it is difficult to industrialize. Therefore, it is necessary to remove impurities such as iron and aluminum from the ore supply end.

[0006] For example, patent document CN101905190A discloses a method for beneficiating collophanite, which comprises the following steps: (1) coarsely grinding the raw collophanite; (2) subjecting the grinding product of step (1) to a magnesium removal flotation agent for reverse flotation to remove magnesium, thereby obtaining magnesium-containing flotation foam and flotation underflow; (3) subjecting the flotation underflow of step (2) to a desulfurization flotation agent for reverse flotation to remove sulfur, thereby obtaining a first sulfur-containing flotation foam and flotation underflow; and (4) subjecting the flotation underflow of step (3) to a desiliconization flotation agent for reverse flotation to remove silicon, thereby obtaining silicon-containing flotation foam. flotation foam and flotation underflow; (5) subjecting the flotation underflow of step (4) to strong magnetic separation and iron removal to obtain magnetic products and non-magnetic products; (6) subjecting the non-magnetic products of step (5) to regrinding; (7) subjecting the grinding products of step (6) to the action of desulfurization flotation reagent, to reverse flotation and desulfurization, to obtain a second flotation foam and flotation underflow containing sulfur; (8) subjecting the flotation underflow of step (7) to the action of dealuminization flotation reagent, to reverse flotation and dealuminization, to obtain flotation foam and flotation underflow containing aluminum, which flotation underflow is the final phosphate concentrate. The method uses too many reagents, which is easy to cause greater pollution and waste of resources.

[0007] CN106179731A A method for removing sesquioxide and magnesium from phosphate ore by coupling high gradient magnetic separation and single reverse flotation, for non-metallic low-grade phosphate ore with a sesquioxide (R203) content of 1.1% to 3.67%. The specific process is as follows: (1) grinding and screening the phosphate ore containing sesquioxide and magnesium, and controlling the slurry concentration to 20 to 35% after slurry adjustment; (2) introducing the slurry into a stirring tank of a high gradient magnetic separator, adding a dispersant alkali metal phosphoric acid; Salt, select a magnetic strength of 1.0-1.7T, magnetically separate the sesquioxides in the phosphate ore to obtain crude phosphate ore and crude tailings; (3) introduce the crude phosphate ore into a ball mill for grinding again, then add flotation reagents, use single reverse flotation to remove magnesium, and obtain high-quality phosphate concentrate with low iron, aluminum and magnesium content. The pH is controlled at 4.0-6.0 during flotation; (4) according to step (3), the crude tailings are subjected to flotation to remove magnesium, and a secondary concentrate is obtained for the production of slurry-based monoammonium phosphate or heavy calcium or ordinary calcium. The method is cumbersome and requires too high equipment.

[0008] Therefore, a mineral processing method for removing iron and aluminum from reverse flotation de-magnesiumized phosphate concentrate and reducing MER is needed to solve the above problems. Summary of the invention

[0009] The purpose of the present invention is to provide a method for beneficiation that combines magnetic flotation to remove iron and aluminum from reverse flotation de-magnesiumized phosphate concentrate and reduce MER. This method solves the technical problem that the existing phosphate ore is mainly de-magnesiumized by reverse flotation, but the impurities such as iron and aluminum are enriched in the concentrate, which is difficult to meet the downstream production of high-end phosphate products.

[0010] The scheme of the present invention is:

[0011] A method for removing iron and aluminum from reverse flotation de-magnesiumized phosphate concentrate and reducing MER by magnetic flotation separation, comprising the following steps:

[0012] S1. The collophosphate ore is subjected to a two-stage grinding process, with the grinding media being steel balls and steel forgings, to grind the ore to a fineness of -0.075mm and a content greater than 83%, and a graded overflow concentration of 22-28%, to obtain a pulp;

[0013] S2, adding an acid to the slurry treated in step S1 for slurry adjustment and mineralization, the mineralization time is 0.5 to 1 minute; then adding a collector, the mineralization time is 1 to 2 minutes, aeration flotation, removing dolomite minerals in the phosphate ore, and obtaining a de-magnesiumized phosphate concentrate with a P2O5 content greater than 27.5%, a MgO content less than 1%, a Fe2O3 content of 0.8 to 2.0%, an Al2O3 content of 1.3 to 3.5%, and a MER value of 0.1 to 0.15:

[0014] S3, the de-magnesiumized phosphate concentrate is diluted with water to a concentration of 1-3%, and fed into a strong magnetic separator, and the magnetic field strength is controlled to be 1.5-1.7T, and the strong magnetic separation operation is performed to obtain a de-ironized phosphate concentrate and a magnetic mixed ore, respectively. The de-ironized phosphate concentrate contains 28-29% P2O5, 0.8-1% MgO, 0.4-0.6% Fe2O3, 0.6-0.8% Al2O3, and a MER value of 0.06-0.08; the magnetic mixed ore contains 26-27% P2O5, 0.8-1% MgO, 8-10% Fe2O3, and 2-5% Al2O3;

[0015] S4, add water to the magnetic mixture to adjust the slurry, control the concentration to 0.5-1%, and separate it by ordinary wet magnetic separator, the magnetic field current is 0.5-2A, and obtain phosphorus-containing iron ore and low-iron medium-grade phosphate ore respectively, the phosphorus-containing iron ore has a P2O5 content of less than 5%, and a Fe2O3 content of more than 45%; the low-iron medium-grade phosphate ore has a P2O5 content of 27-28%, a Fe2O3 content of less than 1%, an Al2O3 content of less than 1.5%, and a MER of less than 0.12. Low-iron medium-grade phosphate ore can be used as a wet process to produce phosphate fertilizer products or a thermal process to produce yellow phosphorus products;

[0016] As a preferred technical solution, the acid agent in step S2 is one of concentrated sulfuric acid or mixed acid, and the mixed acid includes a mixture of concentrated sulfuric acid and concentrated phosphoric acid.

[0017] As a preferred technical solution, the collector is a sodium salt of a fatty acid mainly composed of octadecanoic acid.

[0018] As a preferred technical solution, the number of strong magnetic separation operations in S3 is 1 to 2 times.

[0019] As a preferred technical solution, the number of magnetic separations by a common wet magnetic separator in step S4 is 1 to 2 times.

[0020] As a preferred technical solution, it also includes step S5, treating the phosphorus-containing iron ore to make its Fe2O3 content 45-50% to obtain iron ore. The phosphorus-containing iron ore is treated or directly used as raw material and sold as iron ore resources.

[0021] As a preferred technical solution, the treatment is magnetic separation.

[0022] As a preferred technical solution, the iron in the collophanite in step S1 is mainly limonite, which is a non-magnetic or weakly magnetic mineral; the aluminum is mainly silicate ore; the P2O5 content in the collophanite is 18% to 24%, the MgO content is 4% to 8%, the Fe2O3 content is 0.6 to 1.7%, and the Al2O3 content is 1 to 3%. The aluminum is mainly calcium feldspar (CaAl2Si2O8), mica (KAl2(AlSi3O 10 Mainly silicate minerals such as )(OH)2).

[0023] The de-iron phosphate concentrate can be used to produce high value-added phosphorus products, such as calcium phosphate salts for feed and new battery materials, etc. The low-iron medium-grade phosphate ore can be used to produce phosphate fertilizer products by wet method or yellow phosphorus products by thermal method.

[0024] After flotation, the phosphate concentrate with high iron and aluminum content is further enriched with iron and aluminum. The steel balls consumed in the grinding process and weakly magnetic minerals such as limonite in the phosphate ore are removed through mixing with a high-intensity magnetic separator, thereby reducing the iron and aluminum content in the phosphate concentrate and the MER value in the concentrate. The magnetic mixture is further separated from the phosphate minerals by an ordinary magnetic separator, and the magnetic steel balls and a part of the limonite are removed, thereby further increasing the added value of the phosphate concentrate.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention provides a mineral processing method for removing iron and aluminum from phosphate concentrate by magnetic levitation combined with reverse flotation and de-magnesiumization, and reducing MER. Since the iron-containing and aluminum-containing minerals in phosphate ore are embedded in a small particle size, usually -20 microns can be effectively dissociated, and conventional flotation methods cannot effectively remove them. In addition, since the ore particles are relatively fine and have strong mutual adsorption ability, agglomeration is formed, flotation entrainment is serious, and the phosphorus loss rate is high. Therefore, it is necessary to use strong magnetic separation at a relatively low concentration to first separate the iron-containing minerals from phosphorus, and then use weak magnetic separation to separate the grinding medium from the brown ore, and further recover the phosphate minerals. The present invention is a mineral processing method for further removing impurities from phosphate concentrate with simple process, low cost, and easy industrialization to improve the quality of phosphate concentrate.

[0027] This method uses strong magnetic separation to separate the steel ball medium and weakly magnetic minerals such as limonite and aluminum-containing minerals produced by grinding for reverse flotation demagnesized phosphate concentrate, so as to separate the phosphate concentrate from iron minerals; and then separates the grinding steel ball medium from weakly magnetic limonite and aluminum-containing minerals through wet magnetic separation, so as to separate and utilize the steel ball medium and limonite. Most of the iron and aluminum impurities are removed by magnetic separation, the MER value in the phosphate concentrate is reduced, and the quality of the phosphate concentrate is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0029] 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.

[0030] Embodiment 1:

[0031] The collophanite has a P2O5 content of 23%, a MgO content of 5.5%, a Fe2O3 content of 0.6%, and an Al2O3 content of 0.6%. The collophanite is ground to -0.075 mm with a two-stage two-closed ball mill, and the content accounts for 86%. After grinding, the collophanite has a P2O5 content of 23%, a MgO content of 5.5%, a Fe2O3 content of 0.8%, and an Al2O3 content of 0.6%. The slurry is added with an acid agent for slurry adjustment and mineralization, and the mineralization time is 0.5 minutes. Then, a fatty acid sodium salt mainly composed of octadecanoic acid is added as a collector, and the mineralization time is 2 minutes. The dolomite mineral in the phosphate ore is removed by aeration flotation to obtain a demagnesized phosphate concentrate with a P2O5 content of more than 30%, a MgO content of less than 0.8%, a Fe2O3 content of 0.9%, an Al2O3 content of 0.9%, and a MER value of 0.09. The acid agent is concentrated sulfuric acid.

[0032] The phosphate concentrate is diluted with water to a concentration of 3%, and a strong magnetic separator is used to control the magnetic field to 1.5T to obtain the product iron-free phosphate concentrate (1) with a P2O5 content of 30.5%, a MgO content of 0.7%, a Fe2O3 content of 0.5%, an Al2O3 content of 0.6%, and a MER value of 0.06, which is a low-iron, low-aluminum, and low-magnesium high-quality phosphate concentrate; and a magnetic mixed ore (2) with a P2O5 content of 25%, a MgO content of 0.8%, a Fe2O3 content of 4%, and an Al2O3 content of 2.0%;

[0033] The magnetic mixed ore (2) is diluted with water to a concentration of 0.5%, and a common wet magnetic separator is used to control the magnetic field current to 1A to obtain a product (3) of medium-grade phosphate concentrate with a P2O5 content of 27.5%, a MgO content of 0.7%, a Fe2O3 content of 0.8%, an Al2O3 content of 1.7%, and a MER value of 0.12; the iron mineral (4) has a P2O5 content of 5%, a MgO content of 0.8%, a Fe2O3 content of 45%, and an Al2O3 content of 3%, which can be sold as a product.

[0034] Embodiment 2:

[0035] The collophanite has a P2O5 content of 22%, a MgO content of 5%, a Fe2O3 content of 1%, and an Al2O3 content of 1.6%. The collophanite is ground to -0.075 mm with a two-stage two-closed ball mill, and the content accounts for 88%. After grinding, the collophanite has a P2O5 content of 22%, a MgO content of 5%, a Fe2O3 content of 1.2%, and an Al2O3 content of 1.6%. An acid is added to the slurry for slurry adjustment and mineralization, and the mineralization time is 0.5 minutes. Then, a fatty acid sodium salt mainly composed of octadecanoic acid is added as a collector, and the mineralization time is 2 minutes. The dolomite mineral in the phosphate ore is removed by aeration flotation to obtain a demagnesized phosphate concentrate with a P2O5 content greater than 29%, a MgO content less than 0.8%, a Fe2O3 content of 1.3%, an Al2O3 content of 1.9%, and a MER value of 0.14. The acid is concentrated sulfuric acid.

[0036] The phosphate concentrate was diluted with water to a concentration of 2%, and a strong magnetic separator was used to control the magnetic field to 1.6T to obtain the product iron-free phosphate concentrate (1) with a P2O5 content of 29.5%, a MgO content of 0.7%, a Fe2O3 content of 0.6%, an Al2O3 content of 0.6%, and a MER value of 0.06, which was a low-iron, low-aluminum, and low-magnesium high-quality phosphate concentrate; and a magnetic mixed ore (2) with a P2O5 content of 25.8%, a MgO content of 0.88%, a Fe2O3 content of 8%, and an Al2O3 content of 3%;

[0037] The magnetic mixed ore (2) is diluted with water to a concentration of 0.6%, and a common wet magnetic separator is used to control the magnetic field current to 1A to obtain a product (3) of medium-grade phosphate concentrate with a P2O5 content of 27%, a MgO content of 0.7%, a Fe2O3 content of 0.9%, an Al2O3 content of 1.6%, and a MER value of 0.12; the iron mineral (4) has a P2O5 content of 4.5%, a MgO content of 0.9%, a Fe2O3 content of 48%, and an Al2O3 content of 3%, which can be sold as a product.

[0038] Embodiment 3:

[0039] The collophanite has a P2O5 content of 20%, a MgO content of 6%, a Fe2O3 content of 1.3%, and an Al2O3 content of 1.8%. The collophanite is ground to -0.075 mm with a two-stage two-closed ball mill, and the content accounts for 88%. After grinding, the collophanite has a P2O5 content of 20%, a MgO content of 6%, a Fe2O3 content of 1.5%, and an Al2O3 content of 1.8%. An acid is added to the slurry for slurry adjustment and mineralization, and the mineralization time is 0.5 minutes. Then, a fatty acid sodium salt mainly composed of octadecanoic acid is added as a collector, and the mineralization time is 2 minutes. The dolomite mineral in the phosphate ore is removed by aeration flotation to obtain a demagnesized phosphate concentrate with a P2O5 content greater than 28.5%, a MgO content less than 0.8%, a Fe2O3 content of 1.6%, an Al2O3 content of 2.0%, and a MER value of 0.15. The acid is a mixed acid of sulfuric acid and phosphoric acid.

[0040] The phosphate concentrate slurry was diluted with water to a concentration of 1%, and a strong magnetic separator was used to control the magnetic field intensity to 1.7 T to obtain the product iron-free phosphate concentrate (1) with a P2O5 content of 29%, a MgO content of 0.6%, a Fe2O3 content of 0.5%, an Al2O3 content of 0.6%, and a MER value of 0.06, which was a low-iron, low-aluminum, and low-magnesium high-quality phosphate concentrate; and a magnetic mixed ore (2) with a P2O5 content of 26.5%, a MgO content of 0.9%, a Fe2O3 content of 12%, and an Al2O3 content of 4%;

[0041] The magnetic mixed ore (2) is diluted with water to a concentration of 0.3%, and a common wet magnetic separator is used to control the magnetic field current to 0.5A to obtain a product (3) of medium-grade phosphate concentrate with a P2O5 content of 27.5%, a MgO content of 0.7%, a Fe2O3 content of 1.0%, an Al2O3 content of 1.7%, and a MER value of 0.13; the iron mineral (4) has a P2O5 content of 6%, a MgO content of 1.0%, a Fe2O3 content of 46%, and an Al2O3 content of 4%, which can be sold as a product.

[0042] 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 and aluminum from phosphate concentrate demagnesized by magnetic flotation and reverse flotation and reducing MER, characterized in that: The following steps are involved: S1. The collophosphate ore is subjected to a two-stage grinding process, with the grinding media being steel balls and steel forgings, to grind the ore to a fineness of -0.075mm and a content greater than 83%, and a graded overflow concentration of 22-28%, to obtain a pulp; S2, adding an acid to the slurry treated in step S1 for slurry adjustment and mineralization, the mineralization time is 0.5 to 1 minute; then adding a collector, the mineralization time is 1 to 2 minutes, aeration flotation, removing dolomite minerals in the phosphate ore, and obtaining a de-magnesiumized phosphate concentrate with a P2O5 content greater than 27.5%, a MgO content less than 1%, a Fe2O3 content of 0.8 to 2.0%, an Al2O3 content of 1.3 to 3.5%, and a MER value of 0.1 to 0.15; S3, diluting the de-magnesiumized phosphate concentrate with water to a concentration of 1-3%, feeding it into a high-intensity magnetic separator, controlling the magnetic field strength to 1.5-1.7T, and performing high-intensity magnetic separation to obtain a de-ironized phosphate concentrate and a magnetic mixed ore, respectively. The de-ironized phosphate concentrate contains 28-29% P2O5, 0.8-1% MgO, 0.4-0.6% Fe2O3, 0.6-0.8% Al2O3, and a MER value of 0.06-0.08; the magnetic mixed ore contains 26-27% P2O5, 0.8-1% MgO, 8-10% Fe2O3, and 2-5% Al2O3; S4. Add water to the magnetic mixture to adjust the slurry, control the concentration to be 0.5-1%, and carry out magnetic separation by a common wet magnetic separator with a magnetic field current of 0.5-2A to obtain phosphorus-containing iron ore and low-iron medium-grade phosphate ore respectively. The phosphorus-containing iron ore has a P2O5 content of less than 5% and a Fe2O3 content of greater than 45%; the low-iron medium-grade phosphate ore has a P2O5 content of 27-28%, a Fe2O3 content of less than 1%, an Al2O3 content of less than 1.5%, and a MER of less than 0.

12.

2. A method for removing iron and aluminum from reverse flotation de-magnesiumized phosphate concentrate and reducing MER according to claim 1, characterized in that: In the step S2, the acid agent is one of concentrated sulfuric acid or mixed acid, and the mixed acid is a mixture of concentrated sulfuric acid and concentrated phosphoric acid.

3. A method for removing iron and aluminum from phosphate concentrate demagnesized by magnetic flotation and reverse flotation and reducing MER as claimed in claim 1, characterized in that: The collector is a sodium salt of fatty acid mainly composed of octadecanoic acid.

4. A method for removing iron and aluminum from reverse flotation de-magnesiumized phosphate concentrate and reducing MER as claimed in claim 1, characterized in that: The number of strong magnetic separation operations in S3 is 1 to 2 times.

5. A method for removing iron and aluminum from reverse flotation de-magnesiumized phosphate concentrate and reducing MER as claimed in claim 1, characterized in that: In the step S4, the number of magnetic separations by a common wet magnetic separator is 1 to 2 times.

6. A method for removing iron and aluminum from phosphate concentrate demagnesized by magnetic flotation and reverse flotation and reducing MER as claimed in claim 1, characterized in that: The method further comprises step S5, treating the phosphorus-containing iron ore to make its Fe2O3 content 45-50% to obtain iron ore.

7. A method for removing iron and aluminum from phosphate concentrate demagnesized by magnetic flotation and reverse flotation and reducing MER as claimed in claim 6, characterized in that: The treatment is magnetic separation.

8. A method for removing iron and aluminum from phosphate concentrate demagnesized by magnetic flotation and reverse flotation and reducing MER as claimed in claim 1, characterized in that: The iron in the collophanite in step S1 is mainly limonite, which is a non-magnetic or weakly magnetic mineral; the aluminum is mainly silicate ore; the P2O5 content in the collophanite is 18% to 24%, the MgO content is 4% to 8%, the Fe2O3 content is 0.6 to 1.7%, and the Al2O3 content is 1 to 3%.

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