A method for removing siliceous gangue from medium grade collophanite

Abstract

The application provides a method for removing siliceous gangue from medium-grade collophanite, comprising the following steps: a) after slurry preparation of the raw ore, selective flocculation-sedimentation separation treatment is performed to obtain a suspension and a first concentrate respectively; b) the first concentrate obtained in step a) is subjected to reverse flotation desilication treatment to obtain a reverse flotation desilication froth and a second concentrate respectively. Compared with the prior art, the application adopts specific process steps to achieve overall good interaction, first removes small-size siliceous gangue minerals with small hardness through selective flocculation-sedimentation separation, and then removes large-size siliceous gangue minerals with large hardness through reverse flotation desilication treatment, which can effectively improve the removal efficiency of impurities such as silicon, aluminum and iron, and at the same time, the sedimentation separation of small-size siliceous gangue minerals with small hardness can significantly reduce the adverse effects of fine particles on subsequent flotation.

Description

Technical Field

[0001] This invention relates to the field of phosphate rock beneficiation technology, and more specifically, to a method for removing siliceous gangue from medium-grade phosphate rock. Background Technology

[0002] Phosphate rock is a non-renewable strategic mineral resource, playing a vital role in my country's economic development as an important raw material for the chemical industry and phosphate fertilizers. High-magnesium calcareous phosphate rock is selectively developed and utilized due to mature beneficiation technology and low cost; however, its limited reserves cannot meet the demands of economic growth. The development and utilization of medium- and low-grade siliceous and siliceous-calcareous phosphate rock is particularly important. The difficulty in developing medium- and low-grade siliceous and siliceous-calcareous phosphate rock lies in effectively removing siliceous gangue minerals (silica-alumina impurities). Therefore, there is an urgent need to develop efficient flotation desilication processes to solve the utilization challenges of siliceous phosphate rock.

[0003] Flotation is currently the preferred method for separating phosphate rock from silicate gangue minerals. There are two main categories of methods: The first is direct flotation, which uses anionic collectors to float phosphate rock and depressants to suppress gangue minerals. This process requires heating, consumes a lot of energy, has complex reagent formulations, and its economic efficiency has not been ideal. The second category is reverse flotation, which uses cationic collectors to float silicate minerals. The advantages of this method are: simple reagent formulations and low cost; cationic collectors have strong low-temperature resistance, saving energy; and cationic collectors adsorb quickly on the surface of silicate minerals, simplifying the process. Therefore, cationic reverse flotation desilication technology has greater development potential than anionic direct flotation technology, but it also faces technical challenges such as overly stable flotation foam and poor flotation selectivity. This is because the phosphate rock in my country has a fine particle size, and the ore produces a large number of fine-grained minerals during mechanical crushing. Cationic collectors are sensitive to slime, easily leading to the accumulation of large amounts of overly stable foam, which is difficult to defoam and seriously affects flotation indicators and subsequent operations. This is a common problem in the domestic practice of cationic reverse flotation desilication of collophane, which is the reason why it is difficult to utilize medium and low grade siliceous collophane on a large scale in my country.

[0004] CN202311131642.0 discloses a selective flocculant for reverse flotation of phosphate rock, its preparation method, and its application. A pH adjuster, a selective flocculant, a desilication collector, and a decalcification collector are sequentially added to the phosphate rock slurry, followed by reverse flotation to obtain in-tank phosphate concentrate and frothy tailings. The flocculant selectively adsorbs onto the surface of the phosphate rock, promoting flocculation and settling, reducing phosphorus loss, and optimizing flotation froth. However, fine-grained siliceous gangue minerals still remain in the flotation system, and when using cationic collectors, the problem of sticky foam and low flotation selectivity still exists. CN201911061691.5 discloses a desilication and aluminization collector for reverse flotation of phosphate rock, its preparation method, and its application. The mixed collector used is a mixture of mixed amines, mixed alcohols, and methyl cocoate; it has advantages such as good flotation performance, a wide applicable flotation pH range (between 5 and 10), brittle flotation mineralization foam, and good fluidity. This method, starting with a highly efficient flotation collector, can address the problems of high flotation foam viscosity and poor flotation selectivity to some extent, but it fails to fundamentally solve the adverse effects of fine-grained siliceous minerals on flotation. CN201810480343.0 discloses a method for desilication of carbonaceous phosphate rock via cationic reverse flotation based on foam control, including decarbonization flotation, desliming flotation, and desilication reverse flotation. Desliming flotation can effectively reduce the adverse effects of fine-grained minerals on flotation, but the high grade of the tailings from desliming flotation leads to a high phosphorus loss rate. It can be seen that at present, there is a lack of an efficient method to fundamentally solve the influence of fine-grained minerals on the desilication of cationic collectors via reverse flotation. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a method for removing siliceous gangue from medium-grade collophane ore, which can solve the technical problems of high foam viscosity, excessive foam stability and poor selectivity in the existing reverse flotation desilication of medium-grade collophane ore.

[0006] This invention provides a method for removing siliceous gangue from medium-grade collophane ore, comprising the following steps:

[0007] a) After the raw ore is pulped, selective flocculation-sedimentation separation is carried out to obtain suspended solids and first concentrate, respectively;

[0008] b) The first concentrate obtained in step a) is subjected to reverse flotation desilication treatment to obtain reverse flotation desilication foam and second concentrate, respectively.

[0009] Preferably, the raw ore described in step a) comprises the following components by mass percentage: 30%–40% calcium oxide, 22%–29% phosphorus pentoxide, 1%–3% magnesium oxide, 10%–30% silicon dioxide, 1.5%–10% aluminum oxide, 1.5%–4.5% ferric oxide, and 1%–2% sulfur trioxide.

[0010] Preferably, the pulping process described in step a) specifically includes:

[0011] The raw ore is crushed and wet-milled to a particle size of -0.074mm, accounting for 60% to 90%. Water is added to dilute the ore to obtain a slurry with a solid content concentration of 10% to 35%.

[0012] Preferably, the agent for selective flocculation-sedimentation separation treatment in step a) includes a dispersant and a selective flocculant; the dispersant is selected from one or more of water glass, modified water glass, sodium hexametaphosphate, and polysaccharide agents; the selective flocculant is selected from one or more of modified causticized starch, modified polysaccharide, and modified cellulose.

[0013] Preferably, the mass concentration of the dispersant is 5% to 20%, and the addition amount is 1.0 kg / t to 1.5 kg / t;

[0014] The selective flocculant has a mass concentration of 1% to 4% and an addition amount of 50 kg / t to 150 kg / t.

[0015] Preferably, the settling time of the selective flocculation-sedimentation separation treatment in step a) is 10 to 20 seconds.

[0016] Preferably, the reverse flotation desilication process in step b) uses an aerated single-cell flotation machine with an impeller speed of 1000 rpm to 1500 rpm.

[0017] Preferably, the reverse flotation desilication treatment time in step b) is 1 min to 5 min.

[0018] Preferably, in step b), the reverse flotation desilication treatment involves adding a reverse flotation mixed collector to remove coarse-grained siliceous minerals.

[0019] The reverse flotation mixed collector is a mixture of isotriadecyloxypropylpropylene diamine acetate, isooctanol and polyoxyethylene laurate (9) ester in a mass ratio of (80-86):(7-12):(7-8).

[0020] Preferably, the total amount of the reverse flotation mixed collector is 0.2 kg / t to 0.6 kg / t, and it is added in two parts. The first part is 55% to 65%, and the second part is 45% to 35%. The foam products from the two parts are combined into reverse flotation desilication foam.

[0021] This invention provides a method for removing siliceous gangue from medium-grade collophane ore, comprising the following steps: a) after pulping the raw ore, selective flocculation-sedimentation separation is performed to obtain suspended solids and a first concentrate; b) the first concentrate obtained in step a) is subjected to reverse flotation desilication treatment to obtain reverse flotation desilication foam and a second concentrate. Compared with the prior art, this invention employs specific process steps to achieve better overall interaction. First, selective flocculation-sedimentation separation removes siliceous gangue minerals with low hardness and small particle size, and then reverse flotation desilication treatment removes siliceous gangue minerals with high hardness and large particle size. This effectively improves the removal efficiency of impurities such as silicon, aluminum, and iron. Simultaneously, the sedimentation separation of siliceous gangue minerals with low hardness and small particle size significantly reduces the adverse effects of fine particles on subsequent flotation.

[0022] Meanwhile, the method provided by this invention is simple in process, involves cleaning steps, has mild and easily controllable conditions, and is low in cost, thus having broad application prospects. Attached Figure Description

[0023] Figure 1 A schematic diagram illustrating the principle of the method for removing siliceous gangue from medium-grade collophane ore provided by the present invention;

[0024] Figure 2 This is a process flow diagram of the method for removing siliceous gangue from medium-grade collophane ore provided in Embodiment 1 of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] This invention provides a method for removing siliceous gangue from medium-grade collophane ore, comprising the following steps:

[0027] a) After the raw ore is pulped, selective flocculation-sedimentation separation is carried out to obtain suspended solids and first concentrate, respectively;

[0028] b) The first concentrate obtained in step a) is subjected to reverse flotation desilication treatment to obtain reverse flotation desilication foam and second concentrate, respectively.

[0029] This invention addresses the problems of sticky foam, overly stable foam, poor flotation selectivity, and low phosphorus recovery rate in reverse flotation desilication of medium- and low-grade carbonaceous phosphate rock. It provides a method for efficiently removing siliceous gangue from medium-grade phosphate rock, which can effectively improve the removal efficiency of siliceous gangue, increase the overall phosphorus recovery rate, and achieve controllable foam in reverse flotation desilication.

[0030] The present invention first slurries the raw ore (medium-grade collophane) and then performs selective flocculation-sedimentation separation to remove suspended solids, thereby obtaining suspended solids (desliming tailings) and first concentrate (product in the tank).

[0031] In this invention, the raw ore preferably comprises the following components by mass percentage: 30%–40% calcium oxide, 22%–29% phosphorus pentoxide, 1%–3% magnesium oxide, 10%–30% silicon dioxide, 1.5%–10% aluminum oxide, 1.5%–4.5% ferric oxide, and 1%–2% sulfur trioxide;

[0032] More preferably: 30%–35% calcium oxide, 26%–27% phosphorus pentoxide, 2%–2.5% magnesium oxide, 24%–25% silicon dioxide, 6%–8% aluminum oxide, 1.5%–2% ferric oxide, and 1.5%–1.9% sulfur trioxide.

[0033] In this invention, the pulping process is preferably as follows:

[0034] The raw ore is crushed and wet-milled to a particle size of -0.074mm, accounting for 60% to 90%, and then diluted with water to obtain a slurry with a solid content concentration of 10% to 35%.

[0035] More preferably:

[0036] The raw ore is crushed and wet-milled to a particle size of -0.074mm, accounting for 70% to 80%. Water is added to dilute the ore to obtain a slurry with a solid content concentration of 10% to 20%.

[0037] In this invention, the pulping process is preferably carried out at room temperature, and there are no special restrictions on this.

[0038] In this invention, the agent for selective flocculation-sedimentation separation treatment preferably includes a dispersant and a selective flocculant, more preferably it consists of a dispersant and a selective flocculant.

[0039] In this invention, the dispersant is preferably selected from one or more of water glass, modified water glass, sodium hexametaphosphate, and polysaccharide agents, and more preferably from saline water glass; the selective flocculant is preferably selected from one or more of modified causticized starch, modified polysaccharides, and modified cellulose, and more preferably from modified causticized starch. This invention does not impose any special restrictions on the source of the dispersant and selective flocculant; commercially available products well known to those skilled in the art can be used.

[0040] In this invention, the mass concentration of the dispersant is preferably 5% to 20%, more preferably 8% to 12%, and the addition amount is preferably 1.0 kg / t to 1.5 kg / t, more preferably 1.2 kg / t to 1.3 kg / t; the mass concentration of the selective flocculant is preferably 1% to 4%, more preferably 2% to 3%, and the addition amount is preferably 50 kg / t to 150 kg / t, more preferably 70 kg / t to 100 kg / t.

[0041] In this invention, the settling time of the selective flocculation-sedimentation separation process is preferably 10 to 20 seconds; thereafter, the upper fine-grained siliceous minerals (desliming tailings) are preferably separated by a siphon method, and the lower slurry is the first concentrate (product in the tank).

[0042] Then, the present invention performs reverse flotation desilication treatment on the first concentrate to obtain reverse flotation desilication foam (flotation tailings) and second concentrate (in-tank product).

[0043] In this invention, the reverse flotation desilication treatment preferably adopts an aerated single-cell flotation machine, and its impeller speed is preferably 1000rpm~1500rpm, more preferably 1200rpm~1300rpm.

[0044] In this invention, the reverse flotation desilication treatment time is preferably 1 min to 5 min, more preferably 2 min to 3 min.

[0045] In this invention, the reverse flotation desilication treatment preferably involves adding a reverse flotation mixed collector to remove coarse siliceous minerals by flotation; the reverse flotation mixed collector is preferably a mixture of isotriadecyloxypropylpropylene diamine acetate, isooctanol and polyoxyethylene laurate (9) ester in a mass ratio of (80-86):(7-12):(7-8).

[0046] In this invention, the total amount of the reverse flotation mixed collector is preferably 0.2 kg / t to 0.6 kg / t, more preferably 0.4 kg / t to 0.5 kg / t, and is added in two parts. The first part is 55% to 65% (preferably 60% to 62.5%), and the second part is 45% to 35% (40% to 37.5%). The foam products from the two parts are combined to form reverse flotation desilication foam. No other modifiers are required in the above flotation process.

[0047] Finally, the present invention preferably filters, dries, weighs, and tests the foam product and the product in the tank separately, and calculates the yield and phosphorus recovery rate.

[0048] This invention provides a method for removing siliceous gangue from medium-grade collophane ore. See the schematic diagram for the principle. Figure 1As shown, firstly, medium-grade phosphate rock is dispersed into a pulp and then subjected to selective flocculation-sedimentation separation to remove suspended solids, which are desliming tailings, and the product in the tank is the first concentrate. Secondly, the first concentrate is subjected to flotation separation, and the desilication foam from reverse flotation is flotation tailings, and the product in the tank is the second concentrate. This invention first removes kaolinite, montmorillonite, mica, chlorite and other siliceous gangue minerals with low hardness and small particle size through selective flocculation-sedimentation separation, and then removes quartz, feldspar, chalcedony and other siliceous gangue minerals with high hardness and large particle size through reverse flotation, finally obtaining phosphate minerals. This invention can effectively improve the removal efficiency of impurities such as silicon, aluminum and iron. At the same time, the sedimentation separation of siliceous gangue minerals with low hardness and small particle size can significantly reduce the adverse effects of fine particles on subsequent flotation.

[0049] This invention provides a method for removing siliceous gangue from medium-grade collophane ore, comprising the following steps: a) after pulping the raw ore, selective flocculation-sedimentation separation is performed to obtain suspended solids and a first concentrate; b) the first concentrate obtained in step a) is subjected to reverse flotation desilication treatment to obtain reverse flotation desilication foam and a second concentrate. Compared with the prior art, this invention employs specific process steps to achieve better overall interaction. First, selective flocculation-sedimentation separation removes siliceous gangue minerals with low hardness and small particle size, and then reverse flotation desilication treatment removes siliceous gangue minerals with high hardness and large particle size. This effectively improves the removal efficiency of impurities such as silicon, aluminum, and iron. Simultaneously, the sedimentation separation of siliceous gangue minerals with low hardness and small particle size significantly reduces the adverse effects of fine particles on subsequent flotation.

[0050] Meanwhile, the method provided by this invention is simple in process, involves cleaning steps, has mild and easily controllable conditions, and is low in cost, thus having broad application prospects.

[0051] To further illustrate the present invention, the following embodiments will be described in detail.

[0052] Example 1

[0053] The phosphate rock sample provided in Example 1 of this invention was taken from a region in Guizhou Province. The results of multi-element analysis of the raw ore are shown in Table 1.

[0054] Table 1. Multi-element analysis results of the raw ore (%)

[0055] Element CaO <![CDATA[SiO2]]> <![CDATA[P2O5]]> MgO <![CDATA[Al2O3]]> <![CDATA[SO3]]> <![CDATA[Fe2O3]]> content / % 33.26 24.67 26.24 2.35 7.13 1.85 1.58

[0056] Please see Figure 2 , Figure 2 This is a process flow diagram provided in Embodiment 1 of the present invention; wherein, the specific steps of the method for removing siliceous gangue from medium-grade collophane ore provided in Embodiment 1 of the present invention are as follows:

[0057] The phosphorus pentoxide grade in the phosphate rock (raw ore) provided in Example 1 of this invention is 26.24%. The raw ore is crushed and wet-milled to a fineness of -0.074 mm (75%). Water is added to a beaker to adjust the slurry concentration to 15%, and the temperature is around 20°C. First, 1.2 kg / t of 10% saline water glass is used as a dispersant to disperse the minerals, and 100 g / t of 2% modified causticized starch is used to selectively flocculate the phosphorus minerals. After settling for 15 seconds, the upper fine-grained siliceous minerals are separated by a siphon method. The lower layer slurry was transferred into an aerated single-cell flotation machine and stirred for 3 minutes at an impeller speed of 1200 rpm to ensure uniform mixing. A reverse flotation mixed collector was then added to remove coarse siliceous minerals. The mixed collector was a mixture of isotriadecyloxypropylpropylenediamine acetate, isooctanol, and polyoxyethylene laurate (9) ester in a mass ratio of 86:7:7, with a total dosage of 0.4 kg / t, added in two batches: 0.25 kg / t in the first batch and 0.15 kg / t in the second batch. The froth products from both batches were combined as flotation tailings. The froth product and the product from the cell were filtered, dried, weighed, and analyzed to calculate the yield and phosphorus recovery rate. The experimental results are shown in Table 2 below.

[0058] Table 2. Test results of Example 1

[0059] product Yield / % <![CDATA[Grade (P₂O₅) / %]]> Recovery rate / % flotation concentrate 76.76 29.88 87.17 flotation tailings 13.61 12.53 6.73 Desliming tailings 9.63 16.60 6.10 raw ore 100.00 26.24 100.00

[0060] Example 2

[0061] The raw materials provided in Example 2 of this invention are the same as those in Example 1. The phosphorus pentoxide grade in the phosphate rock (raw ore) is 26.24%. The raw ore is crushed and wet-milled to a fineness of -0.074 mm, accounting for 75%. Water is added to a beaker to adjust the slurry concentration to 15%, and the temperature is around 20°C. First, 1.2 kg / t of 10% saline water glass is used as a dispersant to disperse the minerals, and 70 g / t of 2% modified causticized starch is used to selectively flocculate the phosphorus minerals. After settling for 15 seconds, the upper fine-grained siliceous minerals are separated by a siphon method. The lower layer slurry was transferred into an aerated single-cell flotation machine and stirred for 3 minutes at an impeller speed of 1200 rpm to ensure uniform mixing. A reverse flotation mixed collector was then added to remove coarse siliceous minerals. The mixed collector was a mixture of isotriadecyloxypropylpropylenediamine acetate, isooctanol, and polyoxyethylene laurate (9) ester in a mass ratio of 80:12:8, with a total dosage of 0.5 kg / t, added in two batches: 0.30 kg / t in the first batch and 0.20 kg / t in the second batch. The froth products from both batches were combined as flotation tailings. The froth products and the products from the cell were filtered, dried, weighed, and analyzed to calculate the yield and phosphorus recovery rate. The experimental results are shown in Table 3 below.

[0062] Table 3. Test results of Example 2

[0063] product Yield / % <![CDATA[Grade (P₂O₅) / %]]> Recovery rate / % flotation concentrate 74.54 30.31 86.10 flotation tailings 18.19 14.17 9.82 Desliming tailings 7.27 14.71 4.08 raw ore 100.00 26.24 100.00

[0064] Comparative Example 1

[0065] The raw materials provided in Comparative Example 1 of this invention are the same as those in Example 1. The phosphorus pentoxide grade in the phosphate rock (raw ore) is 26.24%. The raw ore is crushed and wet-milled to a fineness of -0.074 mm, accounting for 75%. Without selective flocculation, the slurry is directly transferred into an aerated single-cell flotation machine. The mixture is stirred for 3 minutes at an impeller speed of 1200 rpm to remove siliceous minerals. A reverse flotation mixed collector is added to remove siliceous minerals. The mixed collector is a mixture of isotriadecyloxypropylpropylenediamine acetate, isooctanol, and polyoxyethylene laurate (9) ester in a mass ratio of 86:7:7. The total amount is 0.4 kg / t, added in two batches: 0.25 kg / t in the first batch and 0.15 kg / t in the second batch. The froth products from both batches are combined as flotation tailings. The froth products and the products in the cell are filtered, dried, weighed, and analyzed to calculate the yield and phosphorus recovery rate. The experimental results are shown in Table 4 below.

[0066] Table 4 shows the experimental results of Comparative Example 1.

[0067] product Yield / % <![CDATA[Grade (P2O5) / %]]> Recovery rate / % flotation concentrate 71.81 28.56 78.16 flotation tailings 28.19 20.33 21.84 raw ore 100.00 26.24 100.00

[0068] Compared to Example 1, the flotation concentrate in Comparative Example 1 was 1.32% lower and the recovery rate was 9.01% lower. This demonstrates the importance of selective flocculation before flotation. Furthermore, the large and stable amount of flotation foam in Comparative Example 1 could negatively impact subsequent operations.

[0069] Comparative Example 2

[0070] The raw materials provided in Comparative Example 2 of this invention are the same as those in Example 1. The raw ore is crushed and wet-milled to a fineness of -0.074 mm, accounting for 75%. Water is added to a beaker to adjust the slurry concentration to 15%, and the temperature is around 20°C. First, 1.2 kg / t of 10% saline water glass is used as a dispersant to disperse the minerals, and 100 g / t of 2% modified causticized starch is used to selectively flocculate the phosphate minerals. After settling for 15 seconds, the upper layer of fine-grained siliceous minerals is separated by siphoning. The lower layer of slurry is transferred to an aerated single-cell flotation machine and stirred for 3 minutes at an impeller speed of 1200 rpm to mix evenly. A reverse flotation mixed collector, dodecyl ammonium bromide, is added to remove coarse-grained siliceous minerals. The collector is added in two batches: 0.25 kg / t in the first batch and 0.15 kg / t in the second batch. The froth products from both batches are combined as flotation tailings. The foam product and the product in the tank were filtered, dried, weighed, and analyzed separately to calculate the yield and phosphorus recovery rate. The experimental results are shown in Table 5 below.

[0071] Table 5 shows the experimental results of Comparative Example 2.

[0072] product Yield / % <![CDATA[Grade (P₂O₅) / %]]> Recovery rate / % flotation concentrate 74.09 29.10 82.16 flotation tailings 16.28 18.92 11.74 Desliming tailings 9.63 16.60 6.10 raw ore 100.00 26.24 100.00

[0073] Compared to Example 1, the flotation concentrate in Comparative Example 1 was 0.78% lower and the recovery rate was 5.01% lower. This demonstrates the importance of using the collector employed in this invention for flotation. Furthermore, the large and stable amount of flotation froth in Comparative Example 1 could adversely affect subsequent operations.

[0074] Comparative Example 3

[0075] The raw materials provided in Comparative Example 3 of this invention are the same as those in Example 1. The raw ore is crushed and wet-milled to a fineness of -0.074 mm, accounting for 75%. Water is added to a beaker to adjust the slurry concentration to 15%, and the temperature is about 20°C. First, 1.2 kg / t of 10% saline water glass is used as a dispersant to disperse the minerals, and 100 g / t of 2% modified causticized starch is used to selectively flocculate the phosphate minerals. The slurry is transferred into an aerated single-cell flotation machine and stirred for 3 minutes at an impeller speed of 1200 rpm to mix evenly. A reverse flotation mixed collector is added to remove coarse siliceous minerals. The mixed collector is a mixture of isotriadecyloxypropylpropylenediamine acetate, isooctanol, and polyoxyethylene laurate (9) ester with a mass ratio of 86:7:7 and a total dosage of 0.4 kg / t. It is added in two batches: 0.25 kg / t in the first batch and 0.15 kg / t in the second batch. The froth products from the two batches are combined as flotation tailings. The foam product and the product in the tank were filtered, dried, weighed, and analyzed separately to calculate the yield and phosphorus recovery rate. The experimental results are shown in Table 6 below.

[0076] Table 6 shows the experimental results of Comparative Example 3.

[0077] product Yield / % <![CDATA[Grade (P₂O₅) / %]]> Recovery rate / % flotation concentrate 72.17 29.75 81.81 flotation tailings 27.83 17.15 18.19 raw ore 100.00 26.24 100.00

[0078] Compared to Example 1, the flotation concentrate in Comparative Example 3 was 0.13% lower and the recovery rate was 5.36% lower. This indicates that selective flocculation followed by sedimentation separation to remove some fine-grained minerals is necessary. Furthermore, the large and stable flotation froth in Comparative Example 1 could negatively impact subsequent operations.

[0079] In summary, compared with the prior art, the beneficial effects of the present invention are: (1) By selectively flocculating phosphate minerals and settling to separate fine-grained silica minerals (especially silica minerals with low hardness and small particle size, such as kaolin and mica), the adverse effects of fine-grained minerals on subsequent flotation separation can be eliminated. Compared with desliming flotation, selective flocculation-sedimentation separation can recover more phosphate minerals when removing fine-grained minerals, thus reducing the phosphorus loss rate; (2) By selectively flocculating phosphate minerals, when removing coarse-grained silica minerals in subsequent reverse flotation, the flotation foam stability is suitable due to the coarse particle size of both useful minerals and gangue minerals, and the flotation selectivity is enhanced, thus reducing the amount of expensive cationic collectors used; (3) By selectively flocculating phosphate minerals, when removing coarse-grained silica minerals in subsequent reverse flotation, the coarse-grained phosphate minerals are not easy to float or be entrained in the foam product due to the flocculent phosphate minerals, so the phosphorus mineral loss rate is low.

[0080] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for removing siliceous gangue from medium-grade collophane ore, characterized in that, Includes the following steps: a) After the raw ore is pulped, selective flocculation-sedimentation separation is carried out to obtain suspended solids and first concentrate, respectively; b) The first concentrate obtained in step a) is subjected to reverse flotation desilication treatment to obtain reverse flotation desilication foam and second concentrate, respectively.

2. The method for removing siliceous gangue from medium-grade collophane ore according to claim 1, characterized in that, The raw ore described in step a) comprises the following components by mass percentage: 30%–40% calcium oxide, 22%–29% phosphorus pentoxide, 1%–3% magnesium oxide, 10%–30% silicon dioxide, 1.5%–10% aluminum oxide, 1.5%–4.5% ferric oxide, and 1%–2% sulfur trioxide.

3. The method for removing siliceous gangue from medium-grade collophane ore according to claim 1, characterized in that, The pulping process described in step a) is as follows: The raw ore is crushed and wet-milled to a particle size of -0.074mm, accounting for 60% to 90%. Water is added to dilute the ore to obtain a slurry with a solid content concentration of 10% to 35%.

4. The method for removing siliceous gangue from medium-grade collophane ore according to claim 1, characterized in that, The agents used in the selective flocculation-sedimentation separation process in step a) include dispersants and selective flocculants; the dispersant is selected from one or more of water glass, modified water glass, sodium hexametaphosphate, and polysaccharide agents; the selective flocculant is selected from one or more of modified causticized starch, modified polysaccharides, and modified cellulose.

5. The method for removing siliceous gangue from medium-grade collophane ore according to claim 4, characterized in that, The dispersant has a mass concentration of 5% to 20% and is added at a rate of 1.0 kg / t to 1.5 kg / t. The selective flocculant has a mass concentration of 1% to 4% and an addition amount of 50 kg / t to 150 kg / t.

6. The method for removing siliceous gangue from medium-grade collophane ore according to claim 1, characterized in that, The settling time for the selective flocculation-sedimentation separation process described in step a) is 10 to 20 seconds.

7. The method for removing siliceous gangue from medium-grade collophane ore according to claim 1, characterized in that, The reverse flotation desilication process described in step b) uses an aerated single-cell flotation machine with an impeller speed of 1000 rpm to 1500 rpm.

8. The method for removing siliceous gangue from medium-grade collophane ore according to claim 1, characterized in that, The reverse flotation desilication process described in step b) takes 1 to 5 minutes.

9. The method for removing siliceous gangue from medium-grade collophane ore according to claim 1, characterized in that, The reverse flotation desilication process described in step b) involves adding a reverse flotation mixed collector to remove coarse-grained siliceous minerals. The reverse flotation mixed collector is a mixture of isotriadecyloxypropylpropylene diamine acetate, isooctanol and polyoxyethylene laurate (9) ester in a mass ratio of (80-86):(7-12):(7-8).

10. The method for removing siliceous gangue from medium-grade collophane ore according to claim 9, characterized in that, The total amount of the reverse flotation mixed collector is 0.2 kg / t to 0.6 kg / t, added in two parts: 55% to 65% in the first part and 45% to 35% in the second part. The foam products from the two parts are combined to form reverse flotation desilication foam.

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