Impurity removal method for tailings after middle-low grade collophanite is subjected to spiral chute reselection

Abstract

The invention relates to a method for removing impurities from tailings after middle-low grade collophanite is reselected through a spiral chute, which comprises the following steps: firstly, putting a tailings sample obtained by reselecting concentrate after collophanite magnesium removal and reverse flotation through the spiral chute into a stirring tank, adding water for pulp mixing, controlling the pulp concentration, stirring and adjusting the pH value; adding an adjusting agent into the uniformly stirred gravity separation tailing pulp, pumping the gravity separation tailing pulp into a hydrocyclone to obtain overflow ore pulp without coarse particles, putting the overflow ore pulp into a stirring tank, controlling the concentration of the ore pulp, and stirring; and continuously adding a pH regulator phosphoric acid and phosphate concentrate powder, and carrying out subsequent flotation by adopting one-time roughing, two-time concentration and two-time scavenging to obtain phosphate concentrate. According to the method, the adjusting agent is added into the tailings obtained by reselecting the collophanite through the spiral chute, adhesion of micro-fine particle phosphorite on the surfaces of coarse particle impurities is fully removed, the coarse particle impurities low in grade are removed through sand setting and tailing discarding in advance through the hydrocyclone, then dealumination reverse flotation is conducted, and the flotation efficiency and indexes of the tailings obtained by reselecting the collophanite through the spiral chute are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of phosphate ore dressing, and in particular relates to a method for removing impurities from tailings of medium- and low-grade collophanite after re-selection in a spiral chute. Background Art

[0002] Among the proven phosphate resources in China, high-grade phosphate reserves account for a relatively small proportion. It is of great significance to use scientific and reasonable methods to recover phosphate concentrate from medium and low-grade phosphate ores. Due to the problem of coarse and fine particle inclusions after grinding, as well as the differences in the properties of different ores, some over-grinding occurs during grinding. In the phosphate gravity separation tailings obtained after spiral chute sorting, the fine-grained phosphate is mixed with a large number of coarse-grained impurities, which reduces the floatability. Therefore, in the flotation stage, excessive collectors are usually used for reverse flotation to remove coarse impurities, resulting in a large amount of flotation foam that is difficult to break, poor fluidity, low flotation efficiency, high flotation agent consumption, and fine-grained apatite is easily brought into the tailings, resulting in a high grade of tailings, low yield and recovery rate, and a great waste of phosphate resources.

[0003] CN114100865B discloses a flotation method for ultra-fine phosphate ore, which obtains coarse-grained pulp and fine-grained pulp after one flotation and then flots separately, which has a certain improvement in flotation index compared with conventional flotation conditions. However, the process is applicable to a narrow particle size range and is not suitable for the re-selection tailings of the medium and low-grade collophanite.

[0004] CN103480483A discloses a combined process of heavy medium beneficiation and forward and reverse flotation of phosphate ore, which uses a three-product heavy medium cyclone for separation to obtain three products. However, in the spiral chute, it is inconvenient to control the width of the strips of the three products, which easily leads to a decrease in yield and recovery rate. Summary of the invention

[0005] The present invention provides a method for removing impurities from tailings of medium- and low-grade collophanite after spiral chute gravity separation, wherein an appropriate amount of adjusting agent is added to the tailings obtained by spiral chute gravity separation of medium- and low-grade collophanite, and low-grade coarse particles are removed by pre-discharging tailings through a hydrocyclone, and the reagent system of dealuminization reverse flotation roughing and fine separation of collophanite is adjusted after adding phosphate concentrate powder, and alcohol and fatty acid surfactants are added to the dealuminization surfactant of the fine separation operation to control the amount of foam, and a foam adjusting agent is added at the same time. The method solves the problems that the particle size composition of fine particles in dealuminization reverse flotation is relatively different, low-grade coarse particles are difficult to float out with foam, and the flotation foam is sticky and has poor fluidity, thereby improving the flotation efficiency of the tailings of the collophanite gravity separation through the spiral chute.

[0006] To achieve the above purpose, the technical scheme adopted by the present invention is: a method for removing impurities from tailings of medium and low-grade collophanite after spiral chute gravity selection, grading the collophanite gravity selection tailings treated with an adjusting agent by a hydrocyclone, discarding the low-grade sand settling tailings, and conducting reverse flotation dealumination of the high-grade overflow, adding a small amount of phosphate concentrate powder, and using different reagent systems for roughing and scavenging. Adding an adjusting agent to the tailings obtained by spiral chute gravity selection of collophanite, fully separating the adhesion of fine-grained phosphate ore on the surface of coarse-grained impurities, pre-discarding the tailings by hydrocyclone sand settling to remove the coarse-grained impurities of low grade, and then conducting dealumination reverse flotation, after adding a small amount of phosphate concentrate powder in advance, adding a foam adjusting agent for roughing and selecting and using different reagent conditions, solves the problem that the particle size composition of fine-grained dealumination reverse flotation of collophanite gravity selection tailings is large, and the low-grade coarse particles are difficult to float out with the foam, and the fluidity of the flotation foam is also greatly improved, thereby improving the flotation efficiency and index of the collophanite gravity selection tailings of the spiral chute.

[0007] A method for removing impurities from tailings of medium- and low-grade collophanite after gravity separation in a spiral chute, the method comprising the following steps: S1. Put the tailings sample obtained by gravity separation of the concentrate from the demagnesified collophanite by spiral chute into a stirring tank, add water to adjust the slurry, control the slurry concentration, stir and adjust the pH; S2. Add a regulator to the gravity separation tailings slurry, stir evenly, then pump it into a hydrocyclone to obtain overflow slurry with coarse particles removed, put it into a stirring tank, control the slurry concentration, and stir; S3, add phosphoric acid to continue adjusting the pH, add a small amount of phosphate concentrate powder, add a dealuminized collector and stir; S4. Flotation adopts a process flow of one roughing selection, two cleaning operations and two scavenging operations. After the roughing selection, foam regulator and dealuminization collector are added in the two cleaning operations respectively to finally obtain phosphate concentrate.

[0008] Furthermore, the tailings obtained from the re-selection of the collophanite in S1 have a P2O5 grade of 20%-25% and an Al2O3 grade of 4%-7%.

[0009] Furthermore, the mass fraction of the tailings with a fineness of -0.074 mm obtained by gravity separation in S1 is 70%-85%, the P2O5 grade of the material with a fineness of +0.074 mm is 14%-18%, the slurry concentration is 10%-20%, and the pH is adjusted to 5.0-5.5. Furthermore, the regulator in S2 is one or more of polyoxyethylene-polyoxypropylene-polyoxyethylene, sodium polyphosphate, sodium pyrophosphate, and sodium hexametaphosphate, preferably the following components by mass percentage: polyoxyethylene-polyoxypropylene-polyoxyethylene 40%-50%, sodium polyphosphate 20-30%, sodium pyrophosphate 15-25%, sodium hexametaphosphate 15-25%, and the amount of the regulator is 180-220g / t, wherein the ratio of polyoxyethylene to polyoxypropylene in polyoxyethylene-polyoxypropylene-polyoxyethylene is 204:72, and the CMC value is 3×10 -6 mol·dm -3 .

[0010] Furthermore, the cone angle of the hydrocyclone in S2 is 8°-10°, the overflow pipe size is 23mm-28mm, the sand settling port size is 3mm-6mm, and the overflow is used for slurry adjustment to control the flotation feed slurry concentration to 20%-25%.

[0011] Furthermore, phosphoric acid is used in S3 to adjust the pH value of the slurry to 4.0-5.0, the added phosphate concentrate powder accounts for 5% of the mass of dry ore in the slurry, the P205 grade is 30-32%, and the -0.074mm content in the phosphate concentrate powder is 70-80%; the added dealuminized collector is one or more of dodecyl ether amine, benzyl dimethyl tetradecyl ammonium chloride, and trimethyl chlorosilane, preferably the following components by mass percentage: 25-45% of dodecyl ether amine, 30-50% of benzyl dimethyl tetradecyl ammonium chloride, and 20-35% of trimethyl chlorosilane.

[0012] Furthermore, the foam adjuster in S4 is composed of polyether ester, modified mineral oil and emulsifier, with 30-55% polyether ester, 20-40% modified mineral oil and 20-30% emulsifier, and the amount of foam adjuster is 250-350g / t. Preferably, the polyether ester is HSH CO40 provided by Hai'an Petrochemical Plant in Jiangsu Province, and the modified mineral oil contains 80% white oil, 5% aluminum stearate, 12% ethylene bis stearamide, and 3% hydrophobic white carbon black by mass percentage. The oil bath is heated to 130°C, maintained for 3 hours, and then cooled to room temperature to obtain the modified mineral oil, and the emulsifier is sorbitan monooleate.

[0013] Furthermore, the amount of dealuminizing collector used in the roughing of S4 is 100g / t-150g / t, and the roughing time is 3-4min.

[0014] Furthermore, the dealuminized collectors selected twice in S4 are one or more of dodecyl ether amine, benzyl dimethyl tetradecyl ammonium chloride, trimethyl chlorosilane, sodium ricinoleate, and isooctyl alcohol, preferably the following components in mass percentage: dodecyl ether amine 15-30%, benzyl dimethyl tetradecyl ammonium chloride 20-40%, trimethyl chlorosilane 10-25%, sodium ricinoleate 15-20%, and isooctyl alcohol 15-20%, the amount of dealuminized collector is 100g / t-130g / t, and the selection is 2.5-3.5min.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1) The grade of phosphate ore decreases and then increases from the inside to the outside on the chute. In the gravity separation tailings obtained after sorting by the spiral chute, the fine-grained phosphate ore is mixed with a large number of coarse-grained impurities. The inventor further verified that the grade of the +0.074mm part of the gravity separation tailings obtained was only 16.57%, and due to the partial over-grinding phenomenon during grinding, the fine-grained minerals are very easy to cover the surface of the coarse-grained particles. Therefore, the present invention adds an adjusting agent to the gravity separation tailings before entering the flotation to fully separate the fine-grained minerals from the surface of the coarse-grained impurities, and then uses a hydrocyclone for classification, sand settling, tailings discarding and impurities removal, and the classification efficiency reaches 94%. The proportion of the +0.074mm part in the gravity separation tailings is reduced from 24.72% to 3.86%, realizing the efficient sorting of medium and low-grade collophane gravity separation tailings. In order to solve the problems of large amount of foam that is difficult to break, poor fluidity, low flotation efficiency and high consumption of flotation reagents in dealuminization reverse flotation of gravity separation tailings, foam regulator and phosphate concentrate powder are added on the basis of hydrocyclone pretreatment, and the reagent systems of dealuminization reverse flotation roughing and scavenging are adjusted respectively to optimize the concentrate indicators.

[0016] 2) The addition of adjusting agents improves the classification efficiency of the hydrocyclone. Its main component is EPE-type amphiphilic block copolymer, which is adsorbed on the surface of fine mineral particles through hydrophobic association and hydrogen bonding forces, strengthening the mutual separation between heterogeneous particles and reducing the consumption of fine-grained particles covering coarse particles with sand settling. The pre-discarding of low-grade coarse particles effectively reduces the consumption of dealuminized reverse flotation collectors, reduces production costs, and avoids adsorption entrainment under high drug consumption. The composite foam adjusting agent used is stable in nature. Adding a small amount of phosphate concentrate powder can regulate the dealuminized reverse flotation roughing and fine separation separately, which significantly enhances the fluidity of the foam, improves the recovery rate of the final concentrate, and significantly improves the grade.

[0017] 3) By adopting the ore dressing process of the present invention, the spiral chute gravity separation tailings are dealuminated and reverse flotated to obtain a phosphate concentrate P205 with a grade of ≥32.24% and a recovery rate of ≥53.29%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1The present invention is a process flow chart of a method for removing impurities from tailings of medium- and low-grade collophanite after gravity separation in a spiral chute.

[0019] Figure 2 Figure 6 shows the poor slurry flow state; Figure 3 A diagram showing that the slurry flow state in Example 6 is better. DETAILED DESCRIPTION

[0020] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with embodiments, but the content of the present invention is not limited to the following examples.

[0021] Unless otherwise specified in the following examples, the reagents used are commercially available chemical reagents or industrial products.

[0022] The sample described in this example is the tailings obtained from a collophanite mine in Yichang after magnesium removal reverse flotation and then spiral chute gravity separation. The results of sample screening and element analysis are shown in Table 1.

[0023] Table 1 Sample sieving and elemental analysis results Particle size / mm Yield / % <![CDATA[P2O5 grade / %]]> <![CDATA[P2O5 distribution rate / %]]> +0.074 24.72 16.57 18.12 -0.074+0.048 7.32 23.47 7.60 -0.048+0.039 3.36 23.84 3.54 -0.039 64.60 24.75 70.73 total 100.00 22.60 100.00 In the foam adjusting agent used in the embodiment, the polyether ester is HSHCO40 provided by Hai'an Petrochemical Plant in Jiangsu Province, and the modified mineral oil contains 80% white oil, 5% aluminum stearate, 12% ethylene bisstearamide, and 3% hydrophobic white carbon black by mass percentage. The oil bath is heated to 130°C, maintained for 3 hours, and then cooled to room temperature to obtain the modified mineral oil, and the emulsifier is sorbitan monooleate.

[0024] Example 1 A method for removing impurities from tailings of medium- and low-grade collophanite after spiral chute gravity separation. This example is a control group, in which no adjusting agent is added and no hydrocyclone is used for pretreatment and classification. No foam adjusting agent is added in the flotation operation, and the reagent system for roughing and concentrating is the same. The process flow is as follows: Figure 1As shown, (1) the dealuminization reverse flotation roughing flotation concentration is controlled at 20%, 2kg / t phosphoric acid and 150g / t dealuminization collector are added, the dealuminization collector contains 2 parts of hexadecylpyridinium bromide, 2 parts of benzyldimethyltetradecylammonium chloride and 2 parts of trimethylchlorosilane by weight, and stirred for 3 minutes to allow the reagent to fully act on the mineral surface to carry out reverse flotation dealuminization. (2) The roughing concentrate is further refined twice. In the first refinement, 150g / t dealuminization collector is added. The reagent composition used is the same as that of the roughing. After stirring for 3 minutes, the foaming is scraped for 3 minutes. The above steps are repeated for the second refinement and foaming to obtain the concentrate product. (3) The tailings from the roughing and the two refinements are collected together and scavenged twice to obtain tailings. The first scavenged tailings are returned to the roughing stage, and the second scavenged tailings are returned to the first scavenging stage. After 5 cycles, a concentrate product with a P2O5 grade of 29.74% is obtained, and the recovery rate is 43.62%.

[0025] Example 2 On the basis of Example 1, a hydrocyclone is added for pretreatment and classification. The feed pressure of the hydrocyclone is controlled to be 0.10 MPa, the concentration of the heavy tailings slurry is 10%, the pH is adjusted to 5.3, the size of the bottom flow port of the hydrocyclone is 4 mm, and the process is as follows: Figure 1 As shown, the recovery rate of the overflow part was 87.41%, the loss rate of -0.074mm particle size was 8.45%, and the classification efficiency was 96.78%. The dealuminization reverse flotation was continued. (1) The flotation concentration of the roughing was controlled to be 20%, and 2kg / t phosphoric acid and 110g / t dealuminization collector were added. The dealuminization mixed collector contained 2 parts of hexadecylpyridinium bromide, 2 parts of benzyldimethyltetradecylammonium chloride, and 2 parts of trimethylchlorosilane by weight. The mixture was stirred for 3 minutes to allow the reagent to fully act on the mineral surface for reverse flotation dealuminization. (2) The roughing concentrate was further refined twice. In the first refinement, 150g / t dealuminization collector was added. The reagent composition was the same as that of the roughing. After stirring for 3 minutes, the mixture was scraped for 3 minutes. The above steps were repeated for the second refinement to obtain the concentrate product. (3) The tailings from the roughing and the two refinements were collected together for two scavenging to obtain tailings. The tailings from the first scavenging were returned to the roughing stage, and the tailings from the second scavenging were returned to the first scavenging. After five cycles, a concentrate product with a P2O5 grade of 30.34% was obtained, with a recovery rate of 47.21%.

[0026] Example 3 On the basis of Example 1, a hydrocyclone is added for pretreatment and classification; the regulator and hydrocyclone in S2 operation are used for pretreatment and classification, and 200g / t of the regulator is added to the spiral chute gravity separation tailings. The regulator contains the following components by mass percentage: 65% sodium polyphosphate, 15% sodium pyrophosphate, and 20% sodium hexametaphosphate. The feed pressure of the hydrocyclone is controlled to be 0.10MPa, the concentration of the heavy tailings slurry is 10%, the pH is adjusted to 5.3, the size of the bottom flow port of the hydrocyclone is 4mm, and the process is as follows: Figure 1 As shown, the overflow recovery rate was 89.37%, the -0.074 mm particle size loss rate was 7.53%, and the classification efficiency was 97.38%. The dealuminization reverse flotation was continued. (1) The flotation concentration of the roughing was controlled to be 20%. 2 kg / t phosphoric acid and 110 g / t dealuminization collector were added. The dealuminization mixed collector contained 2 parts of hexadecylpyridinium bromide, 2 parts of benzyldimethyltetradecylammonium chloride, and 2 parts of trimethylchlorosilane by weight. A foam regulator was added. The following components were calculated by mass percentage: 45% polyether ester, 30% modified mineral oil, 25% emulsifier, and 300 g / t of foam regulator. Stir for 3 minutes to allow the agent to fully act on the mineral surface to carry out reverse flotation dealuminization. (2) The roughing concentrate was further refined twice. 150 g / t dealuminization collector was added for the first refinement. The agent composition was the same as that of the roughing. After stirring for 3 minutes, the foam was scraped for 3 minutes. The above steps were repeated for the second refinement to obtain the concentrate product. (3) The tailings from the roughing and the second cleaning are collected together for two scavenging to obtain tailings. The tailings from the first scavenging are returned to the roughing stage, and the tailings from the second scavenging are returned to the first scavenging. After five cycles, a concentrate product with a P2O5 grade of 30.84% ​​is obtained, and the recovery rate is 49.76%. Adding a regulator before the hydrocyclone separation effectively removes the adhesion of fine phosphate ore on the surface of coarse impurities, reduces the loss of phosphate ore, and thus effectively improves the comprehensive recovery rate of flotation.

[0027] Example 4 On the basis of Example 1, a hydrocyclone is added for pretreatment and classification; the regulator and hydrocyclone in operation S2 are used for pretreatment and classification. 200 g / t of regulator is added to the spiral chute gravity separation tailings. The regulator comprises the following components by mass percentage: 45% polyoxyethylene-polyoxypropylene-polyoxyethylene, 20% sodium polyphosphate, 15% sodium pyrophosphate, and 20% sodium hexametaphosphate, wherein the ratio of polyoxyethylene to polyoxypropylene in polyoxyethylene-polyoxypropylene-polyoxyethylene is 204:72, and the CMC value is 3×10 -6 mol·dm -3 The feed pressure of the hydrocyclone is controlled at 0.10 MPa, the concentration of heavy tailings slurry is 10%, the pH is adjusted to 5.3, the size of the bottom flow port of the hydrocyclone is 4 mm, and the process is as follows: Figure 1As shown, the overflow recovery rate was 90.41%, the -0.074 mm particle size loss rate was 6.45%, and the classification efficiency was 97.78%. The dealuminization reverse flotation was continued. (1) The flotation concentration of the roughing was controlled to be 20%. 2 kg / t phosphoric acid and 110 g / t dealuminization collector were added. The dealuminization mixed collector contained 2 parts of hexadecylpyridinium bromide, 2 parts of benzyldimethyltetradecylammonium chloride, and 2 parts of trimethylchlorosilane by weight. A foam regulator was added. The following components were calculated by mass percentage: 45% polyether ester, 30% modified mineral oil, 25% emulsifier, and 300 g / t of foam regulator. Stir for 3 minutes to allow the agent to fully act on the mineral surface to carry out reverse flotation dealuminization. (2) The roughing concentrate was further refined twice. 150 g / t dealuminization collector was added for the first refinement. The agent composition was the same as that of the roughing. After stirring for 3 minutes, the foam was scraped for 3 minutes. The above steps were repeated for the second refinement to obtain the concentrate product. (3) The tailings from the roughing and the second cleaning are collected together and scavenged twice to obtain tailings. The tailings from the first scavenging are returned to the roughing stage, and the tailings from the second scavenging are returned to the first scavenging. After five cycles, a concentrate product with a P2O5 grade of 31.26% is obtained, and the recovery rate is 50.98%. The use of polyoxyethylene-polyoxypropylene-polyoxyethylene in the adjusting agent further enhances the efficiency of removing the adhesion of fine phosphate ore on the surface of coarse impurities.

[0028] Example 5 On the basis of Example 1, a hydrocyclone is added for pretreatment and classification; the regulator and hydrocyclone in the S2 operation are used for pretreatment and classification; in the S4 operation, the dealuminization reverse flotation adjusts the reagent system of roughing and scavenging respectively. 200g / t of regulator is added to the gravity separation tailings, and the regulator is one or more of polyoxyethylene-polyoxypropylene-polyoxyethylene, sodium polyphosphate, sodium pyrophosphate, and sodium hexametaphosphate. The following components are preferably calculated by mass percentage: polyoxyethylene-polyoxypropylene-polyoxyethylene 45%, sodium polyphosphate 20%, sodium pyrophosphate 15%, sodium hexametaphosphate 20%, wherein the ratio of polyoxyethylene to polyoxypropylene in polyoxyethylene-polyoxypropylene-polyoxyethylene is 204:72, and the CMC value is 3×10 -6 mol·dm -3 The feed pressure of the hydrocyclone is controlled at 0.10 MPa, the concentration of heavy tailings slurry is 10%, the pH is adjusted to 5.3, and the size of the hydrocyclone bottom flow port is 4 mm. The process is as follows: Figure 1As shown. Continue to carry out dealumination reverse flotation, (1) control the flotation concentration to 20%, add 2kg / t phosphoric acid, 300g / t foam regulator, 110g / t dealumination mixed collector, the mixed collector contains 2 parts of hexadecylpyridinium bromide, 2 parts of benzyldimethyltetradecylammonium chloride, 2 parts of trimethylchlorosilane, add foam regulator, the following components by mass percentage: polyether ester 45%, modified mineral oil 30%, emulsifier 25%, foam regulator dosage 300g / t, stir for 3min to allow the reagent to fully act on the mineral surface, and carry out reverse flotation dealumination. (2) The roughing concentrate is further refined twice. In the first refinement, 130g / t of dealuminized mixed collector is added. The mixed collector contains 2 parts of hexadecylpyridinium bromide, 2 parts of benzyldimethyltetradecylammonium chloride, 2 parts of trimethylchlorosilane, 1 part of sodium ricinoleate, and 1 part of isooctyl alcohol by weight. A foam regulator is added, which contains the following components by mass percentage: 45% polyether ester, 30% modified mineral oil, 25% emulsifier, and 300g / t of foam regulator. After stirring for 3 minutes, the foam is scraped for 3 minutes, and the above steps are repeated for the second refinement and scraping to obtain a concentrate product. (3) The tailings from the roughing and the two refinements are collected together and scavenged twice to obtain tailings. The tailings from the first scavenging are returned to the roughing stage, and the tailings from the second scavenging are returned to the first scavenging. After 5 cycles, a concentrate product with a P2O5 grade of 31.54% is obtained, and the recovery rate is 51.39%. By adjusting the scavenging and dealuminizing mixed collector, high-grade concentrate products can be obtained while reducing the overall collector dosage, the recovery rate remains stable, and the production cost is reduced.

[0029] Example 6 On the basis of Example 1, a hydrocyclone is added for pretreatment and classification; the regulator and hydrocyclone in the S2 operation are used for pretreatment and classification; the reagent system of roughing and scavenging is adjusted in the dealuminization reverse flotation in the S4 operation; and 5% by mass of phosphate concentrate powder is added before entering the flotation in the S3 operation. 200g / t of regulator is added to the gravity separation tailings, and the regulator is one or more of polyoxyethylene-polyoxypropylene-polyoxyethylene, sodium polyphosphate, sodium pyrophosphate, and sodium hexametaphosphate. The following components are preferably calculated by mass percentage: polyoxyethylene-polyoxypropylene-polyoxyethylene 45%, sodium polyphosphate 20%, sodium pyrophosphate 15%, sodium hexametaphosphate 20%, wherein the ratio of polyoxyethylene to polyoxypropylene in polyoxyethylene-polyoxypropylene-polyoxyethylene is 204:72, and the CMC value is 3×10 -6 mol·dm -3 The feed pressure of the hydrocyclone is controlled to be 0.10 MPa, the concentration of heavy tailings slurry is 10%, the size of the bottom flow port of the hydrocyclone is 4 mm, and the process is as follows: Figure 1As shown. Continue to carry out dealumination reverse flotation, (1) control the flotation concentration to 20%, add 5% by mass of phosphate concentrate powder, stir evenly, add 2kg / t phosphoric acid, 300g / t foam adjuster, 110g / t dealumination mixed collector, the mixed collector contains 2 parts of hexadecylpyridinium bromide, 2 parts of benzyldimethyltetradecylammonium chloride, 2 parts of trimethylchlorosilane, and the foam adjuster contains the following components by mass percentage: polyether ester 45%, modified mineral oil 30%, emulsifier 25%. Stir for 3 minutes to allow the reagent to fully act on the mineral surface, and carry out reverse flotation dealumination. (2) The rough concentrate is further refined twice, and 130g / t dealumination mixed collector is added in the first refinement, the mixed collector contains 2 parts of hexadecylpyridinium bromide, 2 parts of benzyldimethyltetradecylammonium chloride, 2 parts of trimethylchlorosilane, 1 part of sodium ricinoleate, and 1 part of isooctyl alcohol. Add foam adjuster, the following components by mass percentage: polyether ester 45%, modified mineral oil 30%, emulsifier 25%, foam adjuster dosage 300g / t, stir for 3min, scrape foam for 3min, repeat the above steps for the second selection and scrape foam to obtain concentrate product. (3) The tailings from the roughing and the two selections are collected together and scavenged twice to obtain tailings. The tailings from the first scavenging are returned to the roughing stage, and the tailings from the second scavenging are returned to the first scavenging. After 5 cycles, a concentrate product with a P2O5 grade of 32.24% is obtained, and the recovery rate is 54.79%.

[0030] In this embodiment, it is unexpectedly found that adding phosphate concentrate powder before roughing can help improve the uniformity of foam. See the specific comparison chart. Figure 2 (Without adding phosphate concentrate powder, the foam is fine and sticky, and the fluidity is poor), Figure 3 (Adding phosphate concentrate powder has better fluidity), which is beneficial to improving grade and recovery rate.

[0031] The specific embodiments described herein are merely examples of the present invention, but the present invention is not limited to the above embodiments. Any equivalent replacement made by a person skilled in the art based on the present invention is within the scope of protection of this patent.

Claims

1. A method for removing impurities from tailings of medium and low-grade collophanite after spiral chute gravity separation, characterized in that: The method comprises the following steps: S1. Put the tailings sample obtained by gravity separation of the concentrate from the demagnesified collophanite by spiral chute into a stirring tank, add water to adjust the slurry, control the slurry concentration, stir and adjust the pH; S2. Add a regulator to the gravity separation tailings slurry, stir evenly, then pump it into a hydrocyclone to obtain overflow slurry with coarse particles removed, put it into a stirring tank, control the slurry concentration, and stir; S3, adding phosphoric acid to continue adjusting the pH, adding phosphate concentrate powder, adding dealuminization collector, stirring to prepare for flotation; S4. Flotation adopts a process flow of one roughing selection, two cleaning operations and two scavenging operations. After the roughing selection, foam regulator and dealuminization collector are added in the two cleaning operations respectively to finally obtain phosphate concentrate.

2. The method according to claim 1, characterized in that: The tailings obtained from the re-selection of collophanite in S1 have a P2O5 grade of 20%-25% and an Al2O3 grade of 4%-7%.

3. The method according to claim 1, characterized in that: The mass fraction of the tailings with a fineness of -0.074mm obtained by gravity separation in S1 is 70%-85%, the P2O5 grade of the material with a fineness of +0.074mm is 14%-18%, the slurry concentration is 10%-20%, and the pH is adjusted to 5.0-5.

5.

4. The method according to claim 1, characterized in that: The adjusting agent in S2 is one or more of polyoxyethylene-polyoxypropylene-polyoxyethylene, sodium polyphosphate, sodium pyrophosphate, and sodium hexametaphosphate.

5. The method according to claim 4, characterized in that: The following components of the adjusting agent in S2 are calculated by mass percentage: polyoxyethylene-polyoxypropylene-polyoxyethylene 40%-50%, sodium polyphosphate 20-30%, sodium pyrophosphate 15-25%, sodium hexametaphosphate 15-25%, and the amount of adjusting agent is 180-220g / t, wherein the ratio of polyoxyethylene to polyoxypropylene in polyoxyethylene-polyoxypropylene-polyoxyethylene is (200-210): 72, and the CMC value is 3×10 -6 mol·dm -3 .

6. The method according to claim 1, characterized in that: The cone angle of the hydrocyclone in S2 is 8°-10°, the overflow pipe size is 23mm-28mm, the sand settling port size is 3mm-6mm, and the overflow is used for slurry adjustment to control the flotation feed slurry concentration to 20%-25%.

7. The method according to claim 1, characterized in that: Phosphoric acid is used in S3 to adjust the pH value of the slurry to 4.0-5.0, the added phosphate concentrate powder accounts for 5% of the dry ore mass in the slurry, the P205 grade is 30-32%, and the -0.074mm content in the phosphate concentrate powder is 70-80%; the added dealuminized collector is one or more of dodecyl ether amine, benzyl dimethyl tetradecyl ammonium chloride, and trimethyl chlorosilane, preferably the following components by mass percentage: dodecyl ether amine 25-45%, benzyl dimethyl tetradecyl ammonium chloride 30-50%, and trimethyl chlorosilane 20-35%.

8. The method according to claim 1, characterized in that: The foam regulator in S4 is composed of polyether ester, modified mineral oil and emulsifier, with 30-55% polyether ester, 20-40% modified mineral oil and 20-30% emulsifier, and the dosage of foam regulator is 250-350g / t.

9. The method according to claim 1, characterized in that: The amount of dealuminizing collector used in the roughing of S4 is 100g / t-150g / t, and the roughing time is 3-4min.

10. The method according to claim 1, characterized in that: The dealuminized collectors selected twice in S4 are one or more of dodecyl ether amine, benzyl dimethyl tetradecyl ammonium chloride, trimethyl chlorosilane, sodium ricinoleate, and isooctyl alcohol, preferably the following components by mass percentage: dodecyl ether amine 15-30%, benzyl dimethyl tetradecyl ammonium chloride 20-40%, trimethyl chlorosilane 10-25%, sodium ricinoleate 15-20%, isooctyl alcohol 15-20%, the amount of dealuminized collector is 100g / t-130g / t, and the selection is 2.5-3.5min.

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