Method for preparing nanoscale zircon

Abstract

The invention discloses a method for preparing nanoscale zircon, and belongs to the technical field of natural mineral sample preparation. The preparation method comprises the following steps: (1) grinding zircon raw ore until the zircon monomer dissociation rate reaches more than 80wt% to obtain ground raw ore; (2) the ground raw ore is reselected, gangue minerals with the specific gravity lower than that of zircon minerals are removed, and reselected concentrate is obtained; (3) the gravity concentrate is subjected to magnetic separation, magnetic metal minerals are separated, and zircon concentrate is obtained; (4) the zircon concentrate is subjected to size grading, and coarse-fraction zircon with the particle size being 30 microns or above is separated out; (5) zircon single mineral selection is carried out on the coarse fraction zircon, and selected zircon concentrate is obtained; and (6) grinding the selected zircon concentrate by using a supersonic jet mill to obtain the nanoscale zircon. The preparation method provided by the invention is high in production efficiency, low in cost and convenient to operate, and does not damage the zircon structure.

Description

Technical Field

[0001] The invention relates to the technical field of natural mineral sample preparation, and in particular to a method for preparing nano-scale zircon. Background Art

[0002] Zircon is a kind of accessory mineral widely found in various types of rocks. Because of its characteristics of melting resistance, corrosion resistance, extremely stable chemical properties and rich in trace elements such as U, Th, Hf, REE, it is widely used in isotope dating, tracing of original rock source areas and other geological, geochemical and mineralogical research.

[0003] A Chinese patent (publication number CN105675364A) discloses a method for preparing a zircon mineral particle transmission sample, which comprises: a. placing zircon mineral particles one by one on a glass slide; b. placing a metal mesh on a clean polytetrafluoroethylene block, and then evenly distributing an epoxy resin curing agent in the mesh holes of the metal mesh; c. with the aid of an optical microscope, inserting zircon mineral particles one by one into the mesh holes in the center area of ​​the metal mesh; d. heating and curing the metal mesh and the polytetrafluoroethylene block as a whole, and after curing, removing the metal mesh from the polytetrafluoroethylene block; e. uniformly coating paraffin wax on a preheated glass sheet, and then placing the metal mesh in step d on the glass sheet, and ensuring that the side of the metal mesh that has been in contact with the polytetrafluoroethylene block is in contact with the glass sheet; f. grinding the zircon mineral particles with water using diamond sandpaper to grind the zircon mineral particles that are higher than the surface of the metal mesh to ensure that the metal mesh is exposed to a fresh surface; g. following the operation of step e, gluing the polished side of the metal mesh in step f to the glass piece with paraffin wax, and then bonding the glass piece to the metal block with paraffin wax to cool and solidify; then grinding the zircon mineral particles with water using diamond sandpaper to grind the zircon mineral particles that are higher than the surface of the metal mesh to ensure that the metal mesh is exposed to a fresh surface; h. immersing the glass piece and the metal mesh in acetone as a whole to separate the metal mesh from the glass piece; i. performing ion thinning treatment on the metal mesh to obtain the zircon mineral particle transmission sample. The method combines zircon mineral particles with a metal mesh, a polytetrafluoroethylene block, etc., heats and mixes the whole, and then contacts the semi-solidified state with a paraffin-coated glass sheet and further cools and solidifies. The metal mesh is polished and then separated from the glass sheet. Finally, the metal mesh is subjected to ion thinning treatment to obtain nano-scale zircon.

[0004] However, this method has the following problems: 1) The equipment related to ion thinning is expensive, and only one nanoscale zircon sample can be prepared at a time, resulting in low sample preparation volume and high cost; 2) The heat generated during ion bombardment may cause thermal damage and structural changes on the zircon surface. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a method for preparing nano-scale zircon, which solves the problems in the prior art of low nano-scale zircon preparation amount, high cost, and possible thermal damage or structural change of the prepared nano-scale zircon samples.

[0006] In order to achieve the above object, the present invention provides a method for preparing nanoscale zircon, the method comprising:

[0007] (1) grinding the zircon ore until the zircon monomer dissociation rate reaches more than 80wt% to obtain a ground ore;

[0008] (2) performing gravity separation on the ground ore to remove gangue minerals having a specific gravity lower than that of zircon minerals, thereby obtaining a gravity separation concentrate;

[0009] (3) subjecting the gravity separation concentrate to magnetic separation to separate the magnetic metal minerals to obtain a zircon concentrate;

[0010] (4) subjecting the zircon concentrate to particle size classification to separate coarse-grained zircon with a particle size of more than 30 μm;

[0011] (5) selecting the coarse-grained zircon for single zircon minerals to obtain selected zircon concentrate;

[0012] (6) The selected zircon concentrate is crushed by a supersonic airflow mill to obtain nano-scale zircon.

[0013] The key technology of the present invention is to first determine the monomer dissociation particle size of 80wt% of the zircon mineral in the raw ore sample, grind the particle size of the raw ore to the particle size, so that most of the zircon ores in the raw ore are dissociated, and then utilize the differences in physical properties, crystal characteristics, etc. between zircon minerals and other minerals, integrate and use a variety of mineral enrichment methods, adopt gravity separation and magnetic separation for purification, combine particle size classification and single mineral selection, and greatly ensure the purity of the zircon sample and the final fine grinding efficiency. Finally, a supersonic airflow pulverizer is used to further grind the selected zircon concentrate to the nanometer level, and utilize the differences in the centrifugal force and gravity of zircons of different particle sizes in the gas cyclone field to collect the zircon particles reaching the nanometer level. This method ensures that the original mineral structure, composition, surface properties, etc. of the nanometer-level zircon particles are not affected, and can prepare a large number of nanometer-level zircon particle samples at a low cost to the greatest extent, accurately and continuously prepare nanometer-level zircon particles with high purity and D50 less than 550nm, and meet the needs of certain special fields with strict requirements on zircon particle size.

[0014] In a preferred embodiment, in step (1), the method further comprises first determining the monomer dissociation particle size of more than 80wt% of the zircon minerals in the raw ore sample, and then grinding the zircon ore until the zircon monomer dissociation rate reaches more than 80wt% to obtain the ground ore.

[0015] It should be noted that in step (1), the present invention has no special requirements for the operation method of determining the monomer dissociation particle size of the zircon mineral, and any method known in the art can be used. According to a preferred embodiment, the operation specifically includes:

[0016] The raw ore samples were initially crushed to 1.8-2.2 mm, mixed with epoxy resin and adhered to the frosted glass surface, and baked at 50-70°C for about 8-10 hours. After solidification and hardening, they were placed on a thin slice cutter and cut and ground to a thickness of 100-150 μm. Subsequently, the samples were ground on an automatic rock grinder to a standard thickness of 30 μm, and finally the sample surface was polished with aluminum powder polishing liquid. A scanning electron microscope equipped with an energy spectrometer was used to identify zircons and conduct particle size statistics on the probe sheet to obtain the monomer dissociation particle size of the zircon mineral.

[0017] In a preferred embodiment, in step (1), the grinding conditions include: a rotation speed of 90 to 100 rpm, a time of 8 to 20 min, a grinding concentration of 60 to 80 wt%, and a mill filling rate of 25 to 35%. Studies have shown that grinding under these conditions has a higher grinding efficiency, a more uniform particle size of the ground ore, and a suitable grinding concentration can improve the grinding efficiency.

[0018] In a preferred embodiment, in step (1), the grinding equipment is a ceramic ball mill. The use of a ceramic ball mill can reduce the contamination of the mineral product by the iron medium.

[0019] In a preferred embodiment, in step (2), the reselection operation includes one rough selection and at least one fine selection;

[0020] The conditions for the selection include: a shaking table surface slope of 6° to 10° and a feed slurry concentration of 25 to 35wt%. The inventors utilize the high specific gravity of zircon to re-select the raw ore sample under the optimal conditions, discard the gangue minerals with low specific gravity, and obtain a re-selection concentrate with preliminary enrichment of zircon.

[0021] In a more preferred embodiment, step (2) includes at least two rounds of concentration. Increasing the number of concentrations can produce zircon with higher purity.

[0022] In a preferred embodiment, in step (2), the cleaning conditions further include: the flushing frequency is 20 to 30 times / min, and the water volume is 0.4 to 0.6 t / h.

[0023] In a preferred embodiment, in step (3), the magnetic separation operation includes: performing weak magnetic separation and strong magnetic separation in sequence to separate magnetic metal minerals to obtain zircon concentrate.

[0024] In a preferred embodiment, in step (3), the conditions for weak magnetic separation include: magnetic field strength of 90 to 120 kA / m and feed slurry concentration of 8 to 15 wt%.

[0025] In a preferred embodiment, in step (3), the conditions for high intensity magnetic separation include: magnetic field strength of 20000-23000 Oe, and feed slurry concentration of 8-15 wt%.

[0026] It should be noted that the present invention has no special requirements for the specific operation of the strong magnetic separation. For example, the weak magnetic separation tailings obtained after the weak magnetic separation are subjected to a roughing separation and a second scavenging separation, and the scavenged concentrate is merged into the roughing concentrate.

[0027] The study found that under the conditions of weak and strong magnetic separation, magnetic metal minerals and rare earth minerals can be removed to obtain zircon concentrate.

[0028] In a preferred embodiment, in step (4), a hydrocyclone is used to perform particle size classification on the zircon concentrate.

[0029] In the preferred solution, the parameters of the hydrocyclone include: the overflow port diameter is 30-50 mm and the underflow port diameter is 280-320 mm. The zircon concentrate is passed through the hydrocyclone through the feed port, and fine-grained and coarse-grained ore samples are collected at the overflow port and the underflow port of the hydrocyclone, respectively, to obtain coarse-grained zircon with a particle size range of more than 30 μm and fine-grained zircon with a particle size range of 0-30 μm. Since the particle size of fine-grained zircon is too small, it is difficult to manually select it based on the mineral optical characteristics under a stereo microscope, so only coarse-grained zircon is selected for single mineral selection in the later stage.

[0030] In a preferred embodiment, the coarse-grained zircon has a particle size range of 30 to 500 μm.

[0031] The hydrocyclone provided by the present invention has the advantages of high classification efficiency, high classification accuracy, simple structure, convenient maintenance, low cost, etc.

[0032] In a preferred embodiment, the method further comprises, in step (5), first washing and drying the coarse-grained zircon, and then performing the zircon single mineral selection to obtain a selected zircon concentrate. Washing the coarse-grained zircon can remove zircon surface attachments and impurities to obtain clean zircon, which is more conducive to single mineral selection.

[0033] In a preferred solution, the cleaning operation specifically includes: placing the coarse-grained zircon in a polyester dust removal bag, hanging it above an ultrasonic cleaning machine, and performing ultrasonic cleaning in the presence of water.

[0034] In a preferred embodiment, the ultrasonic cleaning time is 10 to 30 minutes.

[0035] The present invention has no special requirement on the amount of water for ultrasonic cleaning, and the preferred amount of water is such that all the coarse-grained zircon is submerged in the water in the cleaning tank.

[0036] The present invention has no special requirements for the drying conditions, and the conditions known in the art can be used. Exemplarily, the drying conditions include: drying at 20-40° C. for 4-20 hours.

[0037] It should be noted that in step (5), the present invention has no special requirements for the operation method of selecting the zircon single mineral, and any method known in the art can be used. For example, a stereo microscope is used to select the single mineral, and the process is repeated several times until all the selection is completed.

[0038] In a preferred embodiment, in step (6), the parameters of the supersonic airflow mill during the grinding process include: gas pressure of 0.7-0.9 MPa, air consumption of 2-4 m 3 / min. The study found that nano-scale zircon samples can be obtained under this condition. When compressed air passes through the feed injector, negative pressure is generated at the feed port, which sucks the zircon concentrate into the inner cavity of the crushing chamber, and under the high-speed impact and compression of the airflow, the material collides and rubs against each other to further crush it to 0.5-15μm. If the gas pressure is too high, the material may collide with the inner wall of the crushing chamber at high speed, causing wear and contamination of the sample. If the gas pressure is too low, the particle collision kinetic energy is too low, and the crushing particle size cannot meet the nano-level requirements.

[0039] In a preferred embodiment, the Mohs hardness of the selected zircon concentrate is 6 to 7.5.

[0040] In the preferred embodiment, the supersonic airflow mill has the following performance parameters: (1) it can crush materials with a Mohs hardness of eight or above; (2) it contains a closed-circuit classification mechanism. The supersonic airflow mill can classify the crushed materials, and the coarse particles return to the crushing chamber for further crushing. When this type of supersonic airflow mill is used, the zircon particles prepared are smaller and more uniform in size, and the supersonic airflow mill adopts a medium-free spray crushing technology, which can not only ensure the purity of the material, but also ensure that the material flow can be ultra-finely crushed.

[0041] In a preferred embodiment, the zircon ore contains quartz, feldspar, zircon and hematite.

[0042] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0043] (1) The preparation method provided by the present invention has outstanding advantages such as high production efficiency, low cost, and easy operation, and also provides a good reference for the preparation of similar nanoscale mineral samples.

[0044] (2) The present invention only uses gravity, magnetic screening and other processes to screen out zircon concentrate. The zircon concentrate is not contaminated by chemical agents and ironware. The obtained zircon has high purity. The zircon concentrate is then finely ground to the nanometer level using a supersonic airflow mill. The difference in the influence of centrifugal force and gravity on zircons of different particle sizes in a gas cyclone field is utilized to collect the zircon particles reaching the nanometer level, thereby ensuring that the original mineral structure, composition, surface properties, etc. of the nanometer-level zircon particles are not affected.

[0045] (3) According to the mineralogical characteristics of zircon, the purity of the nano-scale zircon provided by the present invention is high by grinding the raw ore sample to the dissociation particle size of the zircon mineral and then performing gravity separation, weak magnetic separation, strong magnetic separation, particle size classification and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a flow chart for preparing nano-scale zircon provided by the present invention;

[0047] Figure 2 This is a characteristic image of the zircon concentrate obtained in step (4) of Example 1 under a stereo microscope;

[0048] Figure 3 is the XRD diffraction pattern of nano-scale zircon obtained in Example 1;

[0049] Figure 4 This is the DLS particle size distribution diagram of the nano-scale zircon obtained in Example 1. DETAILED DESCRIPTION

[0050] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0051] The present invention provides a flow chart for preparing nano-scale zircon, specifically see Figure 1 .

[0052] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the following specific embodiments. Obviously, the embodiments described below are only a part of the embodiments, and all other embodiments obtained by professionals in this field without creative work still belong to the protection scope of the present invention.

[0053] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0054] Example 1

[0055] (1) Determine the monomer dissociation particle size of zircon minerals in the raw ore sample

[0056] The raw ore sample is a rare earth ore: the main mineral components of the -2mm ore are quartz and feldspar, and the heavy minerals are mainly zircon, hematite, magnetite, niobite, ilmenite and monazite.

[0057] The raw ore sample was initially crushed to 2 mm to obtain the primary ground ore, which was placed in a container and mixed with epoxy resin and adhered to the frosted glass surface, baked at 60°C for 9 hours, and after solidification and hardening, it was placed on a thin slice cutter and cut and ground to a thickness of 150 μm. The sample was then ground on an automatic rock grinder to a standard thickness of 30 μm, and finally the sample surface was polished with aluminum powder polishing liquid. The probe piece was used for zircon identification and particle size statistics using a scanning electron microscope equipped with an energy spectrometer, and the monomer dissociation particle size D80 of 80wt% zircon was obtained: 0.5mm.

[0058] (2) According to the statistical results of zircon particle size, 5 kg of the primary ground ore was further ground into the monomer dissociation particle size determined in step (1) using a zircon ball ceramic ball mill to obtain ground ore. The grinding time was 10 min, the grinding concentration was 70 wt%, the mill filling rate was 30%, and the rotation speed was 96 rpm.

[0059] (3) The ground ore was re-selected using a shaking table, with one roughing and two concentrating. The shaking table had a slope of 8°, a flushing frequency of 25 times / min, a water volume of 0.5 t / h, and a feed slurry concentration of 30 wt%. Zircon, monazite, rutile, and metal minerals were enriched in the re-selected concentrate, and a small amount of gangue minerals such as quartz and feldspar were also carried. 505.5 g of re-selected concentrate was obtained, of which the mass fraction of zircon reached 23.57%.

[0060] (4) A weak magnetic separator is used to perform weak magnetic separation on the re-selected concentrate, and a roughing separation is performed once. The magnetic field strength of the weak magnetic separator is 100 kA / m, and the feed slurry concentration is 10 wt %, and ferromagnetic minerals and weak magnetic separation tailings are obtained; the weak magnetic separation tailings are subjected to strong magnetic separation, a roughing separation, and a second scavenging separation, and the scavenging concentrate is merged into the roughing concentrate. The magnetic field strength of the strong magnetic separator is 20000 Oe, and the feed slurry concentration is 10 wt %, and a strong magnetic concentrate rich in weak magnetic rare earth minerals and a strong magnetic tailing rich in zircon are obtained, and 125.8 g of strong magnetic tailings (zircon concentrate) are obtained, wherein the mass fraction of zircon reaches 79.28%.

[0061] (5) A hydrocyclone with an overflow port diameter of 40 mm and an underflow port diameter of 300 mm was selected to perform particle size classification on the zircon concentrate; the zircon concentrate was passed through the hydrocyclone through the feed port, and fine-grained and coarse-grained ore samples were collected at the overflow port and underflow port of the hydrocyclone, respectively, to obtain 92.5 g of coarse-grained zircon with a particle size range of 30 to 500 μm and 29.6 g of fine-grained zircon with a particle size range of 0 to 30 μm.

[0062] (6) 92.5 g of coarse-grained zircon was placed in a polyester dust removal bag and hoisted above an ultrasonic cleaning machine. 350 ml of distilled water was added to the cleaning tank, and the zircon was completely immersed in the cleaning tank water and ultrasonically cleaned. The zircon was placed in an ultrasonic cleaning for 20 minutes and dried at 40° C. for 5 hours to obtain 92.1 g of the dried sample.

[0063] The dried sample was placed on a glass slide, and a stereo microscope was used to select zircon single minerals according to the crystal structure characteristics of zircon minerals, and other impurity minerals were removed to collect the zircon single minerals. This operation was repeated 20 times until all the zircon concentrates were selected, and 25.7g of selected zircon concentrates were obtained.

[0064] (7) Place the selected zircon concentrate into the Venturi self-priming feed port, start the supersonic airflow mill, set the gas pressure to 0.85 MPa, and the air consumption to 3 m 3 / min, and collect nano-scale zircon samples at the solid discharge port of the cyclone separator. The D50 of the obtained sample is 548nm, totaling 25.5g.

[0065] The supersonic air flow mill can crush materials with a Mohs hardness of more than eight and contains a closed-circuit grading mechanism.

[0066] The present invention provides an exemplary characteristic image of the zircon concentrate obtained in step (4) under a stereo microscope, as shown in Figure 2 ,from Figure 2 It can be seen that by combining multiple beneficiation methods, the metal minerals and other impurity minerals in the zircon concentrate samples obtained are significantly reduced, and the zircon purity is high.

[0067] The present invention also provides an example of the nano-scale zircon XRD diffraction pattern obtained in Example 1, specifically see Figure 3 ,from Figure 3 It can be seen that the characteristic peak 2θ value of the sample is 26.91, which is consistent with the characteristic peak 2θ value range of zircon (26.85~27.00). The spectrum morphology is consistent with the characteristics of zircon, and the purity of nano-scale zircon is confirmed.

[0068] The present invention also provides an exemplary DLS particle size distribution diagram of nano-scale zircon obtained in Example 1, as shown in FIG. Figure 4 ,from Figure 4It can be seen from the particle size distribution of the nano-scale zircon samples obtained through the example, wherein 10% of the zircon particle size is ≤286nm, 50% of the zircon particle size is ≤548nm, and 97% of the zircon particle size is ≤1.206μm.

[0069] Example 2

[0070] (1) Determine the monomer dissociation particle size of zircon minerals in the raw ore sample

[0071] The raw ore sample is crushed granite: the main mineral components of -2mm ore are quartz, feldspar, biotite, illite, etc., and the heavy minerals are mainly pyrite, hematite, zircon and barite.

[0072] The raw ore sample was initially crushed to 2 mm to obtain the primary ground ore, which was placed in a container and mixed with epoxy resin and adhered to the frosted glass surface, baked at 60°C for 9 hours, and after solidification and hardening, it was placed on a thin slice cutter and cut and ground to a thickness of 150 μm. The sample was then ground on an automatic rock grinder to a standard thickness of 30 μm, and finally the sample surface was polished with aluminum powder polishing liquid. The probe piece was used for zircon identification and particle size statistics using a scanning electron microscope equipped with an energy spectrometer, and the monomer dissociation particle size D90 of 90wt% zircon was obtained: 0.08mm.

[0073] (2) According to the statistical results of zircon particle size, 5 kg of the primary ground ore was further ground into the monomer dissociation particle size determined in step (1) using a zircon ball ceramic ball mill to obtain ground ore. The grinding time was 18 min, the grinding concentration was 80 wt%, the mill filling rate was 32%, and the rotation speed was 96 rpm.

[0074] (3) The ground ore was re-selected using a shaking table, with one roughing and two concentrating. The shaking table surface slope was 10°, the flushing frequency was 28 times / min, the water volume was 0.5 t / h, and the feed slurry concentration was 28wt%. Zircon, barite and metal minerals were enriched in the re-selected concentrate, and a small amount of gangue minerals such as quartz and feldspar were entrained. 107.2 g of re-selected concentrate was obtained, of which the mass fraction of zircon reached 5.8%.

[0075] (4) A weak magnetic separator is used to perform weak magnetic separation on the re-selected concentrate, and the first roughing separation is carried out. The magnetic field strength of the weak magnetic separator is 110 kA / m, and the feed slurry concentration is 8 wt %, and ferromagnetic minerals and weak magnetic separation tailings are obtained; the weak magnetic separation tailings are subjected to strong magnetic separation, and the first roughing separation and the second scavenging separation are carried out. The scavenging concentrate is combined with the roughing concentrate. The magnetic field strength of the strong magnetic separator is 23000 Oe, and the feed slurry concentration is 13 wt %, and a strong magnetic concentrate rich in weak magnetic rare earth minerals and a strong magnetic tailing rich in zircon are obtained. 51.1 g of strong magnetic tailings (zircon concentrate) are obtained, and the mass fraction of zircon reaches 48.2%.

[0076] (5) A hydrocyclone with an overflow port diameter of 40 mm and an underflow port diameter of 300 mm was selected to perform particle size classification on the zircon concentrate; the zircon concentrate was passed through the hydrocyclone through the feed port, and fine-grained and coarse-grained ore samples were collected at the overflow port and underflow port of the hydrocyclone, respectively, to obtain 28.5 g of coarse-grained zircon with a particle size range of 30 to 500 μm and 17.8 g of fine-grained zircon with a particle size range of 0 to 30 μm.

[0077] (6) 32.5 g of coarse-grained zircon was placed in a polyester dust removal bag and hoisted above an ultrasonic cleaning machine. 350 ml of distilled water was added to the cleaning tank, and the zircon was completely immersed in the cleaning tank water and ultrasonically cleaned. The zircon was placed in an ultrasonic cleaning for 20 minutes and dried at 30° C. for 10 hours to obtain 27.2 g of the dried sample.

[0078] The dried sample was placed on a glass slide, and a stereo microscope was used to select zircon single minerals according to the crystal structure characteristics of zircon minerals, and other impurity minerals were removed to collect the zircon single minerals. This operation was repeated 20 times until all the zircon concentrates were selected, and 9.3g of selected zircon concentrates were obtained.

[0079] (7) Place the selected zircon concentrate into the Venturi self-priming feed port, start the supersonic airflow mill, set the gas pressure to 0.7 MPa, and the air consumption to 4 m 3 / min. A nano-scale zircon sample D60: 550nm 9.1g was collected at the solid discharge port of the cyclone separator.

[0080] The supersonic jet mill is the same as that in Example 1.

[0081] Comparative Example 1

[0082] (1) Determine the monomer dissociation particle size of zircon minerals in the raw ore sample

[0083] The raw ore sample is a rare earth ore: the main mineral components of the -2mm ore are quartz and feldspar, and the heavy minerals are mainly zircon, hematite, magnetite, niobite, ilmenite and monazite.

[0084] The raw ore sample was initially crushed to 2 mm to obtain the primary ground ore, which was placed in a container and mixed with epoxy resin and adhered to the frosted glass surface, baked at 60°C for 9 hours, and after solidification and hardening, it was placed on a thin slice cutter and cut and ground to a thickness of 150 μm. The sample was then ground on an automatic rock grinder to a standard thickness of 30 μm, and finally the sample surface was polished with aluminum powder polishing liquid. The probe piece was used for zircon identification and particle size statistics using a scanning electron microscope equipped with an energy spectrometer, and the monomer dissociation particle size D60 of 60wt% zircon was obtained: 0.8mm.

[0085] (2) According to the statistical results of zircon particle size, 5 kg of the primary ground ore was further ground into the monomer dissociation particle size determined in step (1) using a zircon ball ceramic ball mill to obtain ground ore. The grinding time was 10 min, the grinding concentration was 70 wt%, the mill filling rate was 30%, and the rotation speed was 96 rpm.

[0086] Step (3) is the same as in Example 1, and 578.2 g of gravity-selected concentrate is obtained, in which the mass fraction of zircon reaches 22.15%.

[0087] Step (4) is the same as in Example 1, and 137.5 g of strong magnetic tailings (zircon concentrate) is obtained, in which the mass fraction of zircon reaches 76.13%.

[0088] Step (5) is the same as in Example 1, and 101.4 g of coarse-grained zircon with a particle size range of 30 to 500 μm and 35.2 g of fine-grained zircon with a particle size range of 0 to 30 μm are obtained.

[0089] Step (5) is the same as in Example 1, obtaining 100.9 g of dried sample and 12.1 g of selected zircon concentrate.

[0090] Step (5) is the same as in Example 1, obtaining a nano-scale zircon sample D50: 550nm 11.9g.

[0091] It can be seen from the effect data of the above examples that the method provided by the present invention can be used to prepare nano-scale zircon samples with high purity, and the obtained nano-scale zircon particles retain the original mineral structure, composition, surface properties, etc.

Claims

1. A method for preparing nanoscale zircon, characterized in that: The method includes: (1) grinding the zircon ore until the zircon monomer dissociation rate reaches more than 80wt% to obtain a ground ore; (2) performing gravity separation on the ground ore to remove gangue minerals having a specific gravity lower than that of zircon minerals, thereby obtaining a gravity separation concentrate; (3) subjecting the gravity separation concentrate to magnetic separation to separate the magnetic metal minerals to obtain a zircon concentrate; (4) subjecting the zircon concentrate to particle size classification to separate coarse-grained zircon with a particle size of more than 30 μm; (5) selecting the coarse-grained zircon for single zircon minerals to obtain selected zircon concentrate; (6) The selected zircon concentrate is crushed by a supersonic airflow mill to obtain nano-scale zircon.

2. A method for preparing nanoscale zircon according to claim 1, characterized in that: In step (1), the grinding conditions include: a rotation speed of 90 to 100 rpm, a grinding time of 8 to 20 min, a grinding concentration of 60 to 80 wt%, and a mill filling rate of 25 to 35%.

3. A method for preparing nanoscale zircon according to claim 1 or 2, characterized in that: In step (2), the reselection operation includes one rough selection and at least one fine selection; The conditions for the selection include: a shaking table surface slope of 6° to 10° and a feed slurry concentration of 25 to 35 wt%.

4. A method for preparing nanoscale zircon according to claim 1 or 2, characterized in that: In step (3), the magnetic separation operation includes: performing weak magnetic separation and strong magnetic separation in sequence to separate magnetic metal minerals to obtain zircon concentrate.

5. A method for preparing nanoscale zircon according to claim 4, characterized in that: The conditions of the weak magnetic separation include: magnetic field strength of 90-120 kA / m, feed slurry concentration of 8-15 wt%; And / or, the conditions for the high-intensity magnetic separation include: a magnetic field strength of 20,000 to 23,000 Oe and a feed slurry concentration of 8 to 15 wt%.

6. A method for preparing nanoscale zircon according to claim 1 or 2, characterized in that: In step (4), the zircon concentrate is subjected to particle size classification using a hydrocyclone.

7. A method for preparing nanoscale zircon according to claim 1 or 2, characterized in that: The method also includes, in step (5), first washing the coarse-grained zircon and then selecting the zircon single mineral to obtain a selected zircon concentrate.

8. A method for preparing nanoscale zircon according to claim 1 or 2, characterized in that: In step (6), the parameters of the supersonic airflow mill during the grinding process include: gas pressure of 0.7-0.9 MPa, air consumption of 2-4 m 3 / min.

9. A method for preparing nanoscale zircon according to claim 1 or 2, characterized in that: The zircon ore contains quartz, feldspar, zircon and hematite.

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