Beneficiation method for removing iron-aluminum sesquioxide from high-grade collophanite

Abstract

The application is a beneficiation method for removing iron and aluminum sesquioxide from high-grade collophanite, and belongs to the technical field of mineral processing. The material obtained by crushing, superfine grinding and grading of raw ore is fed into a heavy separation operation to obtain a heavy separation concentrate and a heavy separation tailing; the heavy separation concentrate is fed into a reverse flotation magnesium removal operation buffer tank, and the heavy separation tailing is thickened, re-ground, classified, and then subjected to positive flotation desliming and positive flotation desilication, and the obtained concentrate is fed into the reverse flotation magnesium removal operation; three backwater pools are built to store positive flotation desilication backwater, reverse flotation magnesium removal backwater and heavy separation operation backwater respectively. The method mainly aims at high-grade high-sesquioxide calcareous collophanite, adopts heavy and float combined separation, divides the raw ore into a heavy separation concentrate and a heavy separation tailing through a heavy separation device, and subjects the heavy separation tailing to positive and reverse flotation to obtain a heavy tailing flotation concentrate. The separation process fully utilizes the advantages of positive and reverse flotation and heavy separation, the process flow is stable, the separation effect is good, high-quality phosphorus concentrate is realized, and low-quality phosphorus concentrate can be used.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a beneficiation method for removing iron and aluminum sesquioxides from high-grade collophane. Background Technology

[0002] In traditional wet-process phosphoric acid production, there are specific requirements for iron and aluminum sesquioxides: for Class I phosphate concentrates, the sesquioxide content must not exceed 2.5%; for Class II phosphate concentrates, it must not exceed 3.0%. The content of iron and aluminum oxides in phosphate rock is often expressed as R₂O₃ (R represents Fe and Al, i.e., Fe₂O₃ + Al₂O₃). Iron and aluminum not only interfere with the growth of calcium sulfate crystals but also cause phosphoric acid to form sludge. The reaction of phosphate rock with acid produces insoluble complex phosphates, the precipitation of which, or their removal with gypsum, results in significant P₂O₅ loss. The resulting complex phosphate crystals are fine, increasing the viscosity of the solution and slurry, and easily clogging filter cloth and filter cake pores. Iron and aluminum phosphates also make subsequent processing, such as the concentration and drying of phosphoric acid or ammonium phosphate slurries, difficult, leading to poor product properties and quality decline. Therefore, to reduce the impact on wet-process phosphoric acid and acid-process fertilizer production, it is necessary to minimize the content of iron and aluminum sesquioxides in phosphate concentrates.

[0003] Currently, for high-alumina, high-iron, low-grade siliceous-calcareous phosphate rock, the conventional process flows are the direct-reverse flotation process and the pre-desliming-double reverse flotation process. The direct-reverse flotation process has disadvantages such as fine grinding fineness, fine concentrate particle size, difficulties in concentrate transportation and dewatering, and high concentrate beneficiation costs. Furthermore, the direct-reverse flotation process requires tailings ponds to operate normally, and it is increasingly difficult for new phosphate mines to obtain approval for tailings ponds. On the other hand, the pre-desliming-double reverse flotation process has disadvantages such as poor reagent selectivity, significant influence of slime on the process, severe P2O5 loss during desliming, and ultimately low P2O5 recovery rate in the concentrate. Summary of the Invention

[0004] The technical problem to be solved by this invention is to address the shortcomings of existing technologies by proposing a new beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane. This process is more reasonable and efficient in removing carbonate, iron- and aluminum-containing gangue minerals from collophane.

[0005] The technical problem to be solved by this invention is achieved through the following technical solution. This invention is a beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane ore, characterized by the following steps:

[0006] (1) The medium-high alumina silica phosphate ore is crushed and then ultra-finely crushed and screened to -3mm before being fed into the powder silo.

[0007] (2) The material at the bottom of the fine ore bin is fed into the grinding and classification operation by a disc feeder and then into the gravity separation operation buffer tank;

[0008] (3) The slurry in the buffer tank of the gravity separation operation is pumped to the gravity separation operation to obtain gravity concentrate and gravity tailings;

[0009] (4) The gravity concentrate is fed into the reverse flotation magnesium removal buffer tank, the gravity tailings are fed into the thickener operation, the thickener underflow is fed into the tailings regrinding and classification operation, and the ground slurry is fed into the forward flotation desilication operation buffer tank.

[0010] (5) The direct flotation desliming buffer tank is first fed into the direct flotation desliming operation, and the slurry after desliming is fed into the direct flotation desliming operation. The concentrate from the direct flotation desliming is fed into the reverse flotation demagnesification operation. The tailings from the direct flotation and the tailings from the desliming flotation are fed into the direct flotation tailings dewatering operation. The concentrate from the reverse flotation is fed into the reverse flotation concentrate dewatering operation. The tailings from the reverse flotation are fed into the reverse flotation tailings dewatering operation. Three return water tanks are built to store the return water from the direct flotation desliming, the return water from gravity separation and the return water from the reverse flotation demagnesification, respectively.

[0011] The medium-high alumina silica phosphate ore composition has a P2O5 grade of 27.5%~29.8%, an MgO content of 1.1%~2.5%, a SiO2 content of 11.5%~14.5%, an Al2O3 content of 1.5%~3.0%, and an Fe2O3 content of 1.2%~2.5%.

[0012] The beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane ore according to the present invention is further preferred in the following method: in the ultrafine crushing and screening, a high-pressure roller mill is used for ultrafine crushing, and a tension screen is used for screening.

[0013] The beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane ore, as described in this invention, is further preferred in the following manner: the grinding and classification operation is carried out using a rod mill or a grate ball mill, and the grinding and classification is carried out in two stages. The first stage uses a micro powder sieve or a fine sieve with a sieve aperture size controlled at 0.1~0.15mm, and the second stage uses a hydrocyclone to classify the material with a classification particle size controlled at 74μm. The grinding fineness of the material before flotation is controlled at 55%~65%.

[0014] The present invention discloses a beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane ore. A further preferred method is as follows: the gravity separation operation adopts a two-stage classification plus a one-stage gravity separation. The two-stage classification adopts a hydrocyclone + a micro powder screen. The hydrocyclone is controlled at 10~38μm and the micro powder screen is controlled at 0.5~1mm. The gravity separation uses one or a combination of two of the following: a disturbing bed, a shaking table, a spiral sluice, a belt sluice, and a centrifugal concentrator. The gravity separation operation includes roughing, cleaning, or scavenging.

[0015] The present invention describes a beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane. A further preferred method is as follows: the reverse flotation demagnesification process mainly removes carbonate-containing minerals; the depressant is selected from sulfuric acid, phosphoric acid, phosphate, or a combination of the above reagents; the collector is selected from a combination of fatty acid soap and xanthate; and the reverse flotation operation includes roughing and scavenging.

[0016] The beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane ore according to the present invention is further preferred in the following way: an additional flotation desliming operation is added before the positive flotation desilication operation, and polyacrylamide and No. 2 reagent are selected as the collectors.

[0017] The present invention discloses a beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane. A further preferred method is as follows: the positive flotation operation mainly removes muddy silicate gangue minerals, the flotation environment is alkaline, sodium carbonate is used as a pH adjuster, water glass is used as an inhibitor, and unsaturated fatty acid organic matter is used as a collector. The positive flotation operation includes roughing and cleaning operations.

[0018] The beneficiation method for removing iron, aluminum and sesquioxides from high-grade collophane ore according to the present invention is further preferred in the following method: the gravity separation tailings are regrinded and classified by using a tower mill to further liberate the useful minerals and gangue minerals, and the grinding fineness is -200 mesh 85%~95%.

[0019] The beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane ore, as described in this invention, is further preferred in the following manner: the return water from the gravity separation reflux tank is used for primary grinding and gravity separation operations; part of the return water from the reverse flotation demagnesification reflux tank is used for reverse flotation demagnesification operations, and the other part, after being treated to meet the requirements, is used for direct flotation desiliconization operations; the return water from the direct flotation desiliconization reflux tank can only be used for direct flotation operations and regrinding of gravity separation tailings; the return water from the reverse flotation operation must be treated by a double alkali process before it can be used for direct flotation desiliconization operations.

[0020] The most preferred technical solution of the beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane ore described in this invention is as follows:

[0021] (1) The raw ore is crushed in a conventional manner. The conventional crushing is based on the feed particle size. If the feed particle size is above 500mm, three-stage crushing is adopted. If the feed particle size is below 500mm, two-stage crushing is adopted. The particle size after crushing is controlled above -30mm. The first stage of conventional crushing adopts a jaw crusher, followed by a cone crusher. The finely crushed ore is then fed into an ultra-fine crushing and screening system composed of a high-pressure roller and a vibrating screen for further ultra-fine crushing. The ultra-fine crushing and screening operation adopts a tension screen. The screening particle size is designed according to 3mm. The qualified material under the screen is fed into the powder ore bin, and the material over the screen is returned to the high-pressure roller mill.

[0022] (2) The material at the bottom of the powder ore bin is fed quantitatively to the grinding and classification operation by a disc feeder. The disc feeder adopts frequency conversion speed regulation. The grinding operation adopts a rod mill or a grate ball mill. The classification operation adopts two-stage classification. The first stage adopts a micro powder screen or fine screen with the screen aperture particle size controlled at 0.1~0.15mm. The second stage adopts hydrocyclone classification with the classification particle size controlled at 74μm. The grinding fineness of the material before gravity separation is controlled at 55%~65%. The qualified particle size of the classification operation is fed into the gravity separation operation buffer tank.

[0023] (3) The slurry in the buffer tank of the gravity separation operation is pumped to the gravity separation operation to obtain gravity concentrate and gravity tailings. The gravity separation operation adopts two-stage classification plus one-stage gravity separation. The two-stage classification adopts hydrocyclone + micro powder screen. The hydrocyclone is controlled at 10~38μm and the micro powder screen is controlled at 0.5~1mm. The gravity separation uses one or two combinations of interference bed, shaking table, spiral chute, belt chute and centrifugal concentrator. The gravity separation operation includes roughing, cleaning or scavenging.

[0024] (4) The gravity concentrate is fed into the reverse flotation magnesium removal buffer tank, the gravity tailings are fed into the thickener, the thickener underflow is fed into the tailings regrinding and classification operation, the ground slurry is fed into the direct flotation desilication buffer tank, the gravity tailings are regrinded and classified, and a tower mill is used for grinding to further liberate the useful minerals and gangue minerals. The grinding fineness is -200 mesh 85%~95%. The reverse flotation depressant is sulfuric acid, phosphoric acid, phosphate or a combination of the above reagents, and the collector is a combination of fatty acid soap and xanthate. The reverse flotation operation includes roughing and scavenging.

[0025] (5) The positive flotation desliming buffer tank is first fed into the positive flotation desliming operation. The slurry after desliming is then fed into the positive flotation desliming operation. The concentrate from the positive flotation desliming is fed into the reverse flotation demagnesification operation. The tailings from the positive flotation and the tailings from the desliming flotation are fed into the positive flotation tailings dewatering operation. The concentrate from the reverse flotation is fed into the reverse flotation concentrate dewatering operation. The tailings from the reverse flotation are fed into the reverse flotation tailings dewatering operation. A flotation desliming operation is added before the positive flotation desliming operation. The collectors are polyacrylamide and No. 2 reagent. The positive flotation operation mainly removes muddy silicate gangue minerals. The flotation environment can be alkaline. The alkaline adjuster is sodium carbonate as a pH adjuster and water glass as an inhibitor. The collector is unsaturated fatty acid organic matter. The positive flotation operation includes roughing and cleaning operations.

[0026] (6) The plant has three return water tanks, which store return water from direct flotation desilication, gravity separation, and reverse flotation demagnesification, respectively. The return water from the gravity separation tank can be used for primary grinding and gravity separation operations. Part of the return water from the reverse flotation demagnesification tank is used for reverse flotation demagnesification operations, and the other part is used for direct flotation desilication operations after being treated to meet standards. The return water from the direct flotation desilication tank can only be used for direct flotation operations and gravity separation tailings regrinding operations. The return water from reverse flotation operations must be treated by a double alkali process before it can be used for direct flotation desilication.

[0027] The raw ore composition of medium-high alumina siliceous phosphate rock is as follows: P2O5 grade of 27.5%~29.8%, MgO mass content of 1.1%~2.5%, SiO2 mass content of 11.5%~14.5%, Al2O3 mass content of 1.5%~3.0%, and Fe2O3 mass content of 1.2%~2.5%. The phosphate rock concentrate obtained by the above method has a P2O5 grade of 32.0%~35.0%, MgO mass content of 0.2%~0.8%, and aluminum- and iron-containing sesquioxides (R2O3) mass content of 2.0%~2.6%.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] In this invention, the high-concentration semi-oxide silica-calcium collophane has a simple mineral composition. The phosphorus-bearing mineral is mainly low-carbon fluorapatite, with a small amount of carbon apatite and apatite. The magnesium-bearing gangue minerals are mainly carbonate minerals, the aluminum-bearing gangue minerals are mainly clay silicate minerals such as hydromica and kaolin, and the iron-bearing gangue mineral is mainly pyrite. Among them, collophane and quartz have poor grindability, while dolomite, hydromica, and kaolin have better grindability. Conventional crushing and grinding processes are prone to over-grinding. Adding a high-pressure roller ultrafine crushing operation between fine crushing and grinding can improve the particle size distribution of the subsequent grinding products and provide a better separation environment for subsequent gravity separation. After gravity separation, the products are divided into high and low grades, which are separated by a single reverse flotation demagnesification process and a forward and reverse flotation process, respectively. Compared with the use of all-material forward and reverse flotation, the grinding cost can be reduced by about 50%, and the reagent cost can be reduced by about 50%. The single reverse flotation process, by adding xanthate as an auxiliary collector, can achieve simultaneous removal of iron and magnesium in a single reverse flotation operation. Adding a desliming stage before the direct flotation desilication stage effectively removes fine mud materials up to 10μm, reducing the stability of foam in subsequent direct flotation operations and facilitating the smooth flow of the direct flotation desilication process. The wastewater recirculation process employs separate recirculation; wastewater generated by each operation is thickened and returned to its respective operation as much as possible, effectively avoiding interference between different mineral processing processes.

[0030] This invention is mainly aimed at high-grade, high-silica, calcium-rich phosphate rock. It adopts a combined gravity flotation and separation flotation method, which separates the raw ore into gravity concentrate with a P2O5 content of more than 33% and gravity tailings with a P2O5 content of less than 22%. The gravity tailings are then subjected to forward and reverse flotation to obtain gravity tailings flotation concentrate with a P2O5 content of more than 31%. The separation process makes full use of the advantages of forward and reverse flotation and gravity separation, realizing the high-quality and high-utilization of phosphate concentrate and the utilization of low-quality concentrate. Detailed Implementation

[0031] Example 1, Experiment 1 on the beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane ore:

[0032] (1) The raw ore feed particle size is -600mm. Conventional crushing adopts three-stage open-circuit crushing. The first stage crushing adopts a jaw crusher, and the latter two stages crushing adopt a cone crusher to crush the material to -30mm. The crushed material is fed to the fine crushing pre-screening operation. The screening equipment is a tension screen. The material on the screen is fed to a high-pressure roller mill. The material crushed by the high-pressure roller is returned to the screening operation to form a closed-circuit ultrafine crushing screening. The undersize material is fed to the powder ore bin. The screening particle size is controlled at -3mm.

[0033] (2) The material at the bottom of the ore bin is fed quantitatively to the grinding and classification operation by a disc feeder. The grinding is carried out by a single-stage grinding, and the classification adopts a first-stage pre-classification and a second-stage controlled classification. The disc feeder adopts frequency conversion speed regulation, the grinding operation adopts a grate ball mill, the first-stage pre-classification adopts a hydrocyclone, and the second-stage controlled classification adopts a two-stage classification. The particle size of the first-stage pre-classification and the classification particle size of the second-stage hydrocyclone classification are controlled at 74μm. The first stage adopts a micro powder sieve with a sieve aperture particle size controlled at 0.15mm. The grinding fineness of the material before gravity separation is controlled at 60%. The qualified particle size of the classification operation is fed into the gravity separation operation buffer tank.

[0034] (3) The slurry in the buffer tank of the gravity separation operation is fed to the gravity separation operation by the conveying pump to obtain gravity concentrate and gravity tailings. The conveying pump adopts frequency conversion speed regulation. The gravity separation operation adopts two-stage classification plus one-stage gravity separation. The two-stage classification adopts hydrocyclone + micro powder screen. The hydrocyclone is controlled at 38μm and the micro powder screen is controlled at 0.5mm. The gravity separation adopts one roughing of spiral chute and one scavenging of spiral chute. Finally, gravity concentrate and gravity tailings are produced.

[0035] (4) The gravity concentrate is directly fed to the dewatering operation, which uses a vacuum belt filter. The filtrate from the belt filter is returned to the gravity tailings thickener. The filter cake is sized and fed into the reverse flotation magnesium removal buffer tank. The gravity tailings are fed into the gravity tailings thickener. The overflow from the gravity tailings thickener is returned to the gravity return water tank. The underflow from the thickener is fed into the tailings regrinding and classification operation. The ground slurry is fed into the forward flotation desilication buffer tank. The gravity tailings are regrinded using a tower mill to further liberate the useful minerals and gangue minerals. The grinding fineness is -200 mesh 90%. Phosphoric acid is used as the reverse flotation depressant, and a combination of PA-64 and butyl xanthate is used as the collector in a ratio of 2:1. The reverse flotation operation uses one roughing and one scavenging.

[0036] (5) The direct flotation desliming buffer tank first feeds into the direct flotation desliming operation. The deslimed slurry is then fed into the direct flotation desliming operation. The direct flotation desliming concentrate is fed into the reverse flotation demagnesification operation. The direct flotation tailings and the desliming flotation tailings are fed into the direct flotation tailings dewatering operation. The reverse flotation concentrate is fed into the reverse flotation concentrate dewatering operation. The reverse flotation tailings are fed into the reverse flotation tailings dewatering operation. The filtrate from the direct flotation dewatering operation is returned to the direct flotation return water tank. The filtrate from the reverse flotation concentrate and tailings dewatering operations is returned to the reverse flotation dewatering operation. The collector used in the direct flotation desliming operation is polyacrylamide and reagent #2. The alkaline adjustment agent used in the direct flotation operation is sodium carbonate as the pH adjuster and water glass as the inhibitor. The collector used is reagent #2. The direct flotation operation includes one roughing and one cleaning operation.

[0037] (6) The plant has three return water tanks, which store return water from direct flotation desilication, gravity separation, and reverse flotation demagnesification, respectively. The return water from the gravity separation tank can be used for primary grinding and gravity separation operations. Part of the return water from the reverse flotation demagnesification tank is used for reverse flotation demagnesification operations, and the other part is used for direct flotation desilication operations after being treated to meet standards. The return water from the direct flotation desilication tank can only be used for direct flotation operations and gravity separation tailings regrinding operations. The return water from reverse flotation operations must be treated by a double alkali process before it can be used for direct flotation desilication.

[0038] The ore composition of the high-particulate phosphate rock in the above method is as follows: P2O5 grade 29.46%, MgO mass content 1.20%, SiO2 mass content 14.80%, Al2O3 mass content 1.59%, and Fe2O3 mass content 1.38%.

[0039] The above method yielded a collophane concentrate with a P2O5 grade of 33.20%, a MgO content of 0.55%, and a sesquioxide (R2O3) content of 2.05%.

[0040] Example 2, Experiment 2 on the beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane:

[0041] (1) The raw ore feed particle size is -350mm. Conventional crushing adopts two-stage open-circuit crushing. The first stage crushing adopts a jaw crusher and the second stage crushing adopts a cone crusher to crush the material to -30mm. The crushed material is fed to the fine crushing pre-screening operation. The screening equipment is a tension screen. The material on the screen is fed to a high-pressure roller mill. The material crushed by the high-pressure roller is returned to the screening operation to form a closed-circuit ultrafine crushing screening. The undersize material is fed to the powder ore bin. The screening particle size is controlled at -3mm.

[0042] (2) The material at the bottom of the powder ore bin is fed quantitatively to the grinding and classification operation by a disc feeder. The grinding is a single-stage grinding, and the classification is controlled by a single-stage classification. The disc feeder is frequency-controlled, the grinding operation is a rod mill, and the single-stage classification operation is a cyclone classification. The classification particle size is controlled at 74μm. The grinding fineness of the material before gravity separation is controlled at 65%. The qualified particles of the classification operation are fed into the gravity separation buffer tank.

[0043] (3) The slurry in the buffer tank of the gravity separation operation is fed to the gravity separation operation by the conveying pump to obtain gravity concentrate and gravity tailings. The conveying pump adopts frequency conversion speed regulation. The gravity separation operation adopts one stage of classification plus one stage of gravity separation. The classification adopts hydrocyclone and the hydrocyclone is controlled at 38μm. The gravity separation adopts one roughing of the interference bed and one scavenging of the spiral chute. Finally, gravity concentrate and gravity tailings are produced.

[0044] (4) The gravity concentrate is directly fed to the dewatering operation, which uses a vacuum belt filter. The filtrate from the belt filter is returned to the gravity tailings thickener. The filter cake is slurry-conditioned and then fed into the reverse flotation magnesium removal buffer tank. The gravity tailings are fed into the gravity tailings thickener. The overflow from the gravity tailings thickener is returned to the gravity return water tank. The underflow from the thickener is directly fed into the forward flotation operation. The grinding fineness is -200 mesh 95%. The reverse flotation depressant is sulfuric acid, and the collector is a combination of PA-64 and butyl xanthate in a ratio of 2:1. The reverse flotation operation uses one roughing and one scavenging.

[0045] (5) The direct flotation desilication buffer tank is fed into the direct flotation desilication operation. The concentrate from the direct flotation desilication is fed into the reverse flotation demagnesification operation. The tailings from the direct flotation are fed into the direct flotation tailings dewatering operation. The concentrate from the reverse flotation is fed into the reverse flotation concentrate dewatering operation. The tailings from the reverse flotation are fed into the reverse flotation tailings dewatering operation. The filtrate from the direct flotation dewatering operation is returned to the direct flotation return water tank. The concentrate and tailings dewatering operations and the filtrate are returned to the reverse flotation dewatering operation. The direct flotation operation uses sodium carbonate as the pH adjuster, water glass as the depressant, and No. 2 reagent as the collector. The direct flotation operation includes one roughing and one cleaning operation.

[0046] (6) The plant has three return water tanks, which store return water from direct flotation desilication, gravity separation, and reverse flotation demagnesification, respectively. The return water from the gravity separation tank can be used for primary grinding and gravity separation operations. Part of the return water from the reverse flotation demagnesification tank is used for reverse flotation demagnesification operations, and the other part is used for direct flotation desilication operations after being treated to meet standards. The return water from the direct flotation desilication tank can only be used for direct flotation operations and regrinding of gravity separation tailings. The return water from reverse flotation operations must be treated by a double alkali process before it can be used for direct flotation desilication.

[0047] The ore composition of the high-particulate phosphate rock in the above method is as follows: P2O5 grade 27.98%, MgO mass content 1.50%, SiO2 mass content 15.60%, Al2O3 mass content 1.85%, and Fe2O3 mass content 1.65%.

[0048] The above method yielded a collophane concentrate with a P2O5 grade of 31.50%, a MgO content of 0.75%, and a sesquioxide (R2O3) content of 2.45%.

[0049] Example 3, Experiment 3 on the beneficiation method for removing iron, aluminum, and sesquioxides from high-grade collophane ore:

[0050] (1) The raw ore feed particle size is -500mm. Conventional crushing adopts three-stage open-circuit crushing. The first stage crushing adopts hammer crusher, and the second stage crushing adopts cone crusher to crush the material to -20mm. The crushed material is fed to fine crushing operation. The screening equipment is a tension screen. The material on the screen is fed to high pressure roller mill, and the material under the screen is fed to powder ore bin. The screening particle size is controlled at -3mm.

[0051] (2) The material at the bottom of the ore bin is fed quantitatively to the grinding and classification operation by a disc feeder. The grinding is carried out by a single-stage grinding, and the classification adopts a first-stage pre-classification and a second-stage control classification. The disc feeder adopts frequency conversion speed regulation. The grinding operation adopts a rod mill or a grate ball mill. The first-stage pre-classification adopts a hydrocyclone, and the second-stage control classification adopts a cyclone classification. The classification particle size is controlled at 74μm. The grinding fineness of the material before gravity separation is controlled at 55%. The qualified particle size of the classification operation is fed into the gravity separation operation buffer tank.

[0052] (3) The slurry in the buffer tank of the gravity separation operation is fed to the gravity separation operation by the conveying pump to obtain gravity concentrate and gravity tailings. The conveying pump adopts frequency conversion speed regulation. The gravity separation operation adopts two-stage classification plus one-stage gravity separation. The two-stage classification adopts hydrocyclone + micro powder screen. The hydrocyclone is controlled at 38μm and the micro powder screen is controlled at 0.5mm. The gravity separation adopts one roughing of spiral chute and one scavenging of spiral chute. Finally, gravity concentrate and gravity tailings are produced.

[0053] (4) The gravity concentrate is directly fed to the dewatering operation, which uses a vacuum belt filter. The filtrate from the belt filter is returned to the gravity tailings thickener. The filter cake is fed into the reverse flotation magnesium removal buffer tank after slurry preparation. The gravity tailings are fed into the gravity tailings thickener. The overflow from the gravity tailings thickener is returned to the gravity return water tank. The underflow from the thickener is fed into the tailings regrinding and classification operation. The ground slurry is fed into the forward flotation desilication buffer tank. The gravity tailings are regrinded using a ball mill to further liberate the useful minerals and gangue minerals. The grinding fineness is -200 mesh 90%. The reverse flotation depressant is a mixture of phosphoric acid and sulfuric acid in a ratio of 1:1. The collector is a combination of PA-64 and butyl xanthate in a ratio of 2:1. The reverse flotation operation uses one roughing and one scavenging process.

[0054] (5) The direct flotation desliming buffer tank first feeds into the direct flotation desliming operation. The deslimed slurry is then fed into the direct flotation desliming operation. The direct flotation desliming concentrate is fed into the reverse flotation demagnesification operation. The direct flotation tailings and the desliming flotation tailings are fed into the direct flotation tailings dewatering operation. The reverse flotation concentrate is fed into the reverse flotation concentrate dewatering operation. The reverse flotation tailings are fed into the reverse flotation tailings dewatering operation. The filtrate from the direct flotation dewatering operation is returned to the direct flotation return water tank. The filtrate from the reverse flotation concentrate and tailings dewatering operations is returned to the reverse flotation dewatering operation. The collector used in the direct flotation desliming operation is polyacrylamide and reagent #2. The alkaline adjustment agent used in the direct flotation operation is sodium carbonate as the pH adjuster and water glass as the inhibitor. The collector used is reagent #2. The direct flotation operation includes one roughing and one cleaning operation.

[0055] (6) The plant has three return water tanks, which store return water from direct flotation desilication, gravity separation, and reverse flotation demagnesification, respectively. The return water from the gravity separation tank can be used for primary grinding and gravity separation operations. Part of the return water from the reverse flotation demagnesification tank is used for reverse flotation demagnesification operations, and the other part is used for direct flotation desilication operations after being treated to meet standards. The return water from the direct flotation desilication tank can only be used for direct flotation operations and gravity separation tailings regrinding operations. The return water from reverse flotation operations must be treated by a double alkali process before it can be used for direct flotation desilication.

[0056] The ore composition of the high-particulate phosphate rock in the above method is as follows: P2O5 grade 28.58%, MgO mass content 1.35%, SiO2 mass content 15.20%, Al2O3 mass content 2.15%, and Fe2O3 mass content 1.58%.

[0057] The above method yielded a collophane concentrate with a P2O5 grade of 32.75%, a MgO mass content of 0.85%, and a sesquioxide (R2O3) mass content of 2.45%.

[0058] Example 4: Comparative experiment on beneficiation methods for removing iron, aluminum, and sesquioxides from high-grade collophane ore:

[0059] The raw ore is a high-component semi-oxide type collophane with the following composition: P2O5 grade 29.46%, MgO mass content 1.20%, SiO2 mass content 14.80%, Al2O3 mass content 1.59%, and Fe2O3 mass content 1.38%.

[0060] Crushing and Grinding Process: The raw ore particle size is -300mm. Conventional crushing adopts a two-stage open-circuit crushing method. The first stage crushing uses a jaw crusher, and the second stage crushing uses a cone crusher to crush the material to -30mm. The crushed material is fed to the fine crushing pre-screening operation. The screening equipment uses a tension screen. The material on the screen is fed to a high-pressure roller mill. The material crushed by the high-pressure roller mill is returned to the screening operation to form a closed-circuit ultrafine crushing and screening. The undersize material is fed to the powder ore bin, and the screening particle size is controlled at -3mm. The material at the bottom of the powder ore bin is quantitatively fed to the grinding and classification operation by a disc feeder. The grinding is a single-stage grinding operation. The classification adopts a primary pre-classification and a secondary control classification. The disc feeder adopts frequency conversion speed regulation. The grinding operation uses a rod mill or a grate ball mill. The primary pre-classification uses a hydrocyclone, and the secondary control classification uses a cyclone classification. The classification particle size is controlled at 74μm. The grinding fineness of the material before gravity separation is controlled at 65%. The qualified particle size of the classification operation is fed into the subsequent separation operation.

[0061] Among them, the dual reverse flotation process and the combined gravity flotation-fractional flotation process require grinding the ore to a fineness of -74μm, accounting for 75%.

[0062] Combined gravity flotation-fractional flotation process: Qualified particle sizes from grinding and classification are fed into the gravity separation buffer tank. The slurry in the buffer tank is then pumped to the gravity separation unit to obtain gravity concentrate and tailings. The pump uses variable frequency speed control. The gravity separation unit employs two-stage classification followed by one-stage gravity separation. The two-stage classification uses hydrocyclones and micro-screens, with the hydrocyclone size controlled at 38μm and the micro-screen size at 0.5mm. The gravity separation uses a spiral sluice for one roughing stage and a spiral sluice for one scavenging stage, ultimately producing gravity concentrate and tailings. The gravity concentrate is directly... The material is fed into the dewatering process, which uses a vacuum belt filter. The filtrate from the belt filter is returned to the gravity separation tailings thickener. The filter cake is then fed into the reverse flotation magnesium removal buffer tank after slurry preparation. The gravity separation tailings are fed into the gravity tailings thickener. The overflow from the gravity separation tailings thickener is returned to the gravity separation return water tank. The underflow from the thickener is fed into the tailings regrinding and classification process. The ground slurry is fed into the forward flotation desilication buffer tank. The gravity separation tailings are regrinded using a ball mill to further liberate the valuable minerals and gangue minerals. The grinding fineness is -200 mesh 90%. The reverse flotation depressant is a mixture of phosphoric acid and sulfuric acid in a 1:1 ratio. The collector is a combination of PA-64 and butyl xanthate in a 2:1 ratio. The reverse flotation operation consists of one roughing and one scavenging phase. The direct flotation desilication buffer tank first feeds the direct flotation desliming operation. The deslimed slurry is then fed into the direct flotation desilication operation. The direct flotation desilication concentrate is fed into the reverse flotation demagnesification operation. The tailings from the direct flotation and desliming flotation are fed into the direct flotation tailings dewatering operation. The reverse flotation concentrate is fed into the reverse flotation concentrate dewatering operation. The reverse flotation tailings are fed into the reverse flotation tailings dewatering operation. The filtrate from the direct flotation dewatering operation is returned to the direct flotation return water tank. The filtrate from the reverse flotation concentrate and tailings dewatering operations is returned to the reverse flotation dewatering operation. The collectors used in the direct flotation desliming operation are polyacrylamide and reagent #2. Sodium carbonate is used as the pH adjuster and water glass as the depressant. The direct flotation operation includes a primary roughing and a primary cleaning process. The plant has three return water tanks: one for direct flotation desilication, one for gravity separation, and one for reverse flotation demagnesification. The return water from the gravity separation tank can be used for primary grinding and gravity separation. Part of the return water from the reverse flotation demagnesification tank is used for reverse flotation demagnesification, and the remaining portion, after treatment, is used for direct flotation desilication. The return water from the direct flotation desilication tank can only be used for direct flotation and gravity tailings regrinding. The return water from the reverse flotation operation must undergo a dual-alkali treatment process before being used for direct flotation desilication. The return water from the gravity separation return water tank can be used for primary grinding and gravity separation operations. Part of the return water from the reverse flotation demagnesification return water tank is used for reverse flotation demagnesification operations, and the other part is used for direct flotation desiliconization operations after being treated to meet the requirements. The return water from the direct flotation desiliconization return water tank can only be used for direct flotation operations and gravity separation tailings regrinding operations. The return water from the reverse flotation operation must be treated by a double alkali process before it can be used for the direct flotation desiliconization process.

[0063] Forward and reverse flotation: Qualified particles from grinding and classification are fed into the forward flotation desilication buffer tank. Forward flotation uses sodium carbonate as the pH adjuster and water glass as the depressant. The collector is reagent #2. Forward flotation includes one roughing and one cleaning operation. The forward flotation concentrate is fed into the reverse flotation demagnesification operation. The reverse flotation depressant is a mixture of phosphoric acid and sulfuric acid at a 1:1 ratio. The collector is a combination of PA-64 and butyl xanthate at a 2:1 ratio. Reverse flotation consists of one roughing and one scavenging operation. The plant has two return water tanks, one for forward flotation desilication and the other for reverse flotation demagnesification. Part of the return water from the reverse flotation demagnesification tank is used for reverse flotation demagnesification, and the other part, after treatment, is used for forward flotation desilication. The return water from the forward flotation desilication tank is used for forward flotation, while the return water from reverse flotation must undergo a double-alkali treatment process before being used for forward flotation desilication.

[0064] Desliming-Reverse Flotation Process: Qualified particles from the grinding and classification process are first fed into a hydrocyclone desliming unit to remove material up to -38μm. The hydrocyclone underflow is then fed into the reverse flotation (RFF) magnesium removal unit. The RFF magnesium removal desliming inhibitor is a mixture of phosphoric acid and sulfuric acid at a 1:1 ratio, and the collector is a combination of PA-64 and butyl xanthate at a 2:1 ratio. The RFF magnesium removal concentrate is then fed into the RFF desilication unit, which uses MAC as the collector. The RFF process includes one roughing and one finishing stage. The hydrocyclone overflow and the RFF desilication concentrate are mixed and dewatered to obtain the final concentrate. The plant has two return water tanks, which store reverse flotation desiliconization return water and reverse flotation demagnesium return water respectively. Part of the return water from the reverse flotation desiliconization return water tank is used for reverse flotation desiliconization operation, and the other part is used for reverse flotation demagnesium operation after being treated to meet the standards. The return water from the reverse flotation demagnesium return water tank is used for reverse flotation demagnesium operation.

[0065] The table below compares the cost and product technical specifications of the process of this invention with those of conventional forward and reverse flotation processes and dual reverse flotation processes:

[0066] .

Claims

1. A beneficiation process for the removal of iron and aluminum sesquioxide from high grade collophanite, characterized in that, The steps are as follows: (1) the high-aluminum and silicon collophanite raw ore is crushed, then is screened to-3mm by superfine crushing, and is fed into the powder ore bin; (2) the material at the bottom of the powder ore bin is fed into the grinding and grading operation by the disc feeder, and is fed into the heavy separation operation buffer tank; (3) the slurry in the heavy separation operation buffer tank is fed into the heavy separation operation by the delivery pump, and the heavy separation concentrate and the heavy separation tailings are obtained; (4) the heavy separation concentrate is fed into the reverse flotation magnesium removal buffer tank, the heavy separation tailings are fed into the thickener operation, the underflow of the thickener is fed into the tailings regrinding and grading operation, and the ground slurry is fed into the positive flotation silicon removal operation buffer tank; (5) the positive flotation silicon removal operation buffer tank is first fed into the positive flotation desliming operation, the deslimed slurry is fed into the positive flotation silicon removal operation, the positive flotation silicon removal concentrate is fed into the reverse flotation magnesium removal operation, the positive flotation tailings and the desliming flotation tailings are fed into the positive flotation tailings dewatering operation, the reverse flotation concentrate is fed into the reverse flotation concentrate dewatering operation, and the reverse flotation tailings are fed into the reverse flotation tailings dewatering operation; three backwater pools are built to store the positive flotation silicon removal backwater, the heavy separation backwater and the reverse flotation magnesium removal backwater respectively. The high-aluminum and silicon collophanite raw ore group has a P2O5 grade of 27.5% to 29.8%, a MgO mass content of 1.1% to 2.5%, a SiO2 mass content of 11.5% to 14.5%, an Al2O3 mass content of 1.5% to 3.0%, and an Fe2O3 mass content of 1.2% to 2.5%; In the superfine crushing and screening, the high-pressure roller mill is used for superfine crushing, and the flip-flow screen is used for screening; The rod mill or the lattice-type ball mill is used for grinding in the grinding and grading operation, two-stage grading is used, the first stage uses the micro-powder screen or the fine screen, the screen hole size is controlled to be 0.1 to 0.15mm, the second stage uses the cyclone classifier, the classification particle size is controlled to be 74μm, and the grinding fineness of the material before flotation is controlled to be 55% to 65%.

2. A beneficiation process for the removal of iron and aluminum sub-oxides from high grade collophanite according to claim 1, characterized in that: Two-stage grading plus one-stage heavy separation is used in the heavy separation operation, the cyclone + micro-powder screen is used for two-stage grading, the cyclone is controlled to be 10 to 38μm, and the micro-powder screen is controlled to be 0.5 to 1mm, one of the disturbance bed, the shaking table, the spiral chute, the belt chute and the centrifugal concentrator and the combination of two kinds are used for heavy separation, and the heavy separation operation includes roughing, cleaning or scavenging.

3. A beneficiation process for the removal of iron and aluminum sub-oxides from high grade collophanite according to claim 1, characterized in that: The reverse flotation magnesium removal process mainly removes the carbonate-containing mineral, the depressant is selected from sulfuric acid, phosphoric acid, phosphate or the combination of the above agents, the collector is selected from the combination of fatty acid soap and xanthate, and the reverse flotation operation includes roughing and scavenging.

4. A beneficiation process for the removal of iron and aluminum sub-oxides from high grade collophanite according to claim 1, characterized in that: The flotation desliming operation is added before the positive flotation silicon removal operation, the collector is selected from polyacrylamide and 2# agent.

5. A beneficiation process for the removal of iron and aluminum sub-oxides from high grade collophanite according to claim 1, characterized in that: The positive flotation operation mainly removes argillaceous silicate gangue minerals, the flotation environment is alkaline, the alkaline adjusting agent is selected from sodium carbonate as the pH adjusting agent, the water glass is used as the depressant, the collector is selected from unsaturated fatty acid organic matter, and the positive flotation operation includes roughing and cleaning operations.

6. A beneficiation process for the removal of iron and aluminum sub-oxides from high grade collophanite according to claim 1, characterized in that: The regrinding and grading operation of the heavy separation tailings uses the tower mill for grinding to further dissociate the useful minerals and the gangue minerals, and the grinding fineness is-200 mesh 85% to 95%.

7. A beneficiation process for the removal of iron and aluminum sub-oxides from high grade collophanite according to claim 1, characterized in that: The backwater of the backwater pool is used for the grinding and gravity separation, the backwater of the backwater pool of reverse flotation and magnesium removal is partly used for the reverse flotation and magnesium removal, and the other part is used for the positive flotation and silicon removal after treatment. The backwater of the backwater pool of positive flotation and silicon removal can only be used for the positive flotation and gravity separation of tailings, and the backwater of the reverse flotation can only be used for the positive flotation and silicon removal after double-alkali treatment.