A method for separating and enriching zirconium minerals from alkaline rock-type rare earth ores

Abstract

The present invention provides a method for separating and enriching zircon minerals from alkaline rock-type rare earth ores, and relates to the technical field of mineralogy. The present invention recovers zircon from rare earth niobium flotation tailings by preferentially flotating rare earth and niobium minerals; adopts the "superconducting strong magnetic separation + shaking table gravity separation" method to preliminarily enrich weakly magnetic zircon and non-magnetic zircon; through the "ultrafine grinding-microbubble flotation-centrifugal gravity separation" method, a zircon collector with good effect is obtained by compounding, assembling and saponifying reagents, and finally a high-grade zircon concentrate is obtained by step-by-step enrichment, thereby achieving accurate and efficient recovery of zircon. The ZrO2 grade in the zircon concentrate is 55.63%, and the recovery rate is 60.82%. The present invention overcomes the technical difficulties of low (weakly magnetic) zircon recovery rate and dissociation and recovery of fine-grained zircon in the complex mineral system of alkaline rock-type rare earth ores, laying the foundation for the efficient enrichment and economic utilization of zircon in such deposits.

Description

Technical Field

[0001] The present invention relates to the technical field of mineralogy, and in particular to a method for separating and enriching zirconium minerals from alkaline rock-type rare earth ores. Background Art

[0002] Rare earth resources contained in alkaline rock masses (such as alkaline granites and pegmatites, alkaline rocks, alkaline syenites, and igneous carbonatites) are all classified as alkaline rock-type deposits. It is estimated that the majority of the world's rare earth resources come from alkaline rock-type deposits. Alkaline rock-type deposits not only contain abundant rare earth resources but are also often associated with large quantities of strategic rare elements (such as Zr, Nb, Ta, U, Th, and Be). They are important rare earth deposits with significant economic and strategic value. Alkaline rock masses are typically rich in volatiles (F, Cl, H2O, and CO2), and have strong complexing and enrichment abilities for high-field-strength elements, which is a key factor in the mineralization of these rock masses. However, this also leads to the high abundance of valuable elements, complex mineral compositions, and diverse interbedded relationships in alkaline rock-type rare earth ores. Common useful minerals in alkaline rock-type rare earth ores include rare earth minerals (fluorocarbon cerium ore, monazite, xinganite, yttrium niobate, etc.), niobium minerals (niobate iron ore, pyrochlore, etc.), zircon minerals (zircon, etc.), uranium minerals (niobate titanium uranium ore, crystalline uranium ore, etc.); gangue minerals include quartz, sodium iron amphibole, nepheline, albite, orthoclase, etc.

[0003] Zircon, a common ore mineral in alkaline rock-type rare earth deposits, is an important carrier mineral for rare elements such as Zr and U. However, there are currently two difficulties in the separation and enrichment of zircon. On the one hand, due to the large number and complexity of high-field strength elements in the mineralization system of this type of deposit, zircon often contains elements such as Y, Fe, and Ce. While increasing the economic value of zircon, it also increases its magnetism and floatability, making it more difficult to separate and enrich zircon. On the other hand, in alkaline rock-type deposits, there are often a variety of minerals closely associated with zircon, and the embedded particle size is fine. The premise of mineral separation and enrichment is to achieve monomer dissociation through fine grinding, but excessive fine grinding leads to ore mudification, which is not conducive to the effective recovery of zircon.

[0004] Currently, there are few reports on the separation and enrichment of zircon from alkaline rock-type rare earth ores. Gao Yude et al. (Gao Yude, Han Zhaoyuan, Wang Guosheng. Experimental Study on the Beneficiation of a Complex and Refractory Tantalum-Niobium-Zirconium Ore in North Korea [J]. Metal Mines, 2012(7):91-94.) once obtained a tantalum-niobium-zirconium mixed concentrate through flotation, but the zircon grade was only 24.95%, which did not meet industrial grade. Existing zircon separation processes are mainly carried out for seaside placer mines and zircon-containing polymetallic mines. Due to the large differences in the mineral composition of the ores, their reference value for zircon from alkaline rock-type rare earth ores is limited. At present, the zircon separation processes in coastal sand mines and zircon-containing polymetallic ores include: (1) gravity separation process, which is one of the mainstream processes for zircon beneficiation. It uses the characteristics of zircon's high specific gravity to recover zircon in the gravity separation concentrate. This process has poor recovery effect on fine-grained minerals; (2) magnetic separation process, which is often used in combination with gravity separation and flotation process (Cao Yongdan, Liu Yunlong, Deng Zhongcheng, et al. Experimental study on impurity removal and quality improvement of low-grade zircon ore [J]. Journal of Inner Mongolia University of Science and Technology, 2022, 41(1): 2-26.), and zircon is initially enriched in non-magnetic products (magnetic separation tailings); (3) flotation process, which is often used in combination with gravity separation and magnetic separation process, is a method to obtain high-grade zircon concentrate, but it needs to be carried out under acidic conditions (Huang Kaifei. High-efficiency flotation technology for complex ores [J]. Foreign Mineral Processing Express, 1997(9): 19-23.), has high requirements on equipment, and requires heated flotation, which is costly.

[0005] Due to the unique physical and chemical properties of zircon in alkaline rock-type rare earth ores, its separation from some rare earth and niobium minerals is poor via gravity and magnetic separation, resulting in low zircon recovery and grade. There is an urgent need to develop a method for separating and enriching zircon from alkaline rock-type rare earth ores. Summary of the Invention

[0006] The object of the present invention is to provide a method for separating and enriching zircon minerals from alkaline rock-type rare earth ores, which can achieve accurate and efficient recovery of zircon.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a method for separating and enriching zirconium minerals from alkaline rock-type rare earth ores, comprising the following steps:

[0009] The alkaline rock type rare earth ore is crushed and finely ground in sequence to obtain ore powder, wherein the mass proportion of -200 mesh particles in the ore powder is 85-95%;

[0010] The ore powder is mixed with water to obtain a first slurry; ammonium bicarbonate is added to the first slurry, and the mixture is stirred; sodium silicate is then added, and the mixture is stirred; then, a collector A solution and kerosene are added, the mixture is stirred continuously, and aeration flotation is performed to obtain a rare earth niobium mixed concentrate and flotation tailings;

[0011] The flotation tailings are blended into a second slurry; the second slurry is subjected to a shaking table gravity separation to obtain a shaking table gravity separation concentrate and a shaking table gravity separation tailings;

[0012] The shaking table gravity separation tailings are mixed into a third pulp; the third pulp is subjected to superconducting strong magnetic separation to obtain a magnetic product and a non-magnetic product;

[0013] The shaker gravity separation concentrate and the magnetic product are combined to prepare a fourth slurry; the fourth slurry is subjected to ultrafine grinding to obtain a fifth slurry; the mass proportion of -400 mesh ore particles in the fifth slurry is 85-95%;

[0014] adding caustic starch to the fifth slurry, stirring, continuing to add collector B solution and collector C solution, aerating and performing microbubble flotation roughing to obtain zircon roughing concentrate and zircon roughing tailings;

[0015] The zircon roughing concentrate is poured into a flotation machine, filled with micro-nano bubbles for micro-bubble flotation selection to obtain a selected zircon concentrate and selected tailings; the selected tailings are returned to the flotation roughing selection;

[0016] The zircon rougher tailings are subjected to centrifugal gravity separation to obtain centrifugal gravity separation concentrate and centrifugal gravity separation tailings;

[0017] combining the centrifugal gravity concentrate and the selected zircon concentrate to obtain a final zircon concentrate;

[0018] The preparation method of the collector A solution comprises the following steps: mixing refined tall oil, phthalic acid and p-tert-butylbenzohydroxamic acid in a mass ratio of 1:(1-2):1 to obtain collector A; mixing the collector A with a 0.5-5 wt% NaOH solution and performing saponification to obtain a collector A solution, wherein the mass fraction of the collector A solution is 1-6%;

[0019] The preparation method of the collector B solution comprises the following steps: mixing 2-ethylhexyl phosphate and coconut oil fatty acid in a mass ratio of (1-3):1 to obtain collector B; mixing the collector B with a 0.5-5 wt% NaOH solution and saponifying the mixture to obtain a collector B solution, wherein the mass fraction of the collector B solution is 1-6%;

[0020] The preparation method of the collector C solution comprises the following steps: mixing arsenazo III and bis(2,4,4-trimethylpentyl)phosphonic acid) in a mass ratio of 1:(2-4) to achieve agent assembly to obtain collector C; mixing the collector C with 0.5-5wt% NaOH solution for saponification to obtain collector C solution, wherein the mass fraction of the collector C solution is 1-6%.

[0021] Preferably, the mass concentration of the first slurry is 15-55%, and the temperature is 10-40°C.

[0022] Preferably, the amount of ammonium bicarbonate added is 500-1000 g / t; the amount of sodium silicate added is 1500-2500 g / t; the amount of collector A solution added is 500-800 g / t based on the amount of collector A; and the amount of kerosene added is 100-300 g / t.

[0023] Preferably, the mass concentration of the second slurry is 15-30%; and the inclination angle of the shaking table during gravity separation is 2-10°.

[0024] Preferably, the mass concentration of the third slurry is 10-20%.

[0025] Preferably, the background magnetic induction intensity of the superconducting strong magnetic separation is 4 to 5T.

[0026] Preferably, the mass concentration of the fourth slurry is 40-60%.

[0027] Preferably, the amount of the caustic starch added is 400-600 g / t; the amount of the collector B solution added is 2000-4000 g / t based on the amount of collector B; and the amount of the collector C solution added is 1000 g / t based on the amount of collector C.

[0028] Preferably, the conditions for the centrifugal gravity separation include: a centrifugal concentrator speed of 90 to 120 G, and a flushing water pressure of 50 to 70 kPa.

[0029] Preferably, 0 to 400 g / t of caustic starch is added during the microbubble flotation selection.

[0030] The present invention addresses the two problems faced in the separation and enrichment of zircon in alkaline rock-type rare earth ores, namely, the zircon selectivity is similar to that of other minerals, and it is difficult to balance fine grinding and dissociation with efficient recovery. Based on the weak magnetic characteristics of some zircons, combined with the differences in the main mineral composition, distribution characteristics and mineral properties in the ore, with the goal of obtaining high-grade and high-recovery zircon concentrate, a method suitable for the efficient enrichment of zircon in such ores is invented. The method comprises the following steps: preferentially flotating rare earth and niobium minerals to recover zircon from rare earth and niobium flotation tailings; adopting the "superconducting strong magnetic separation + shaking table gravity separation" method to preliminarily enrich weakly magnetic zircon and non-magnetic zircon; and adopting the "ultrafine grinding-microbubble flotation-centrifugal gravity separation" method to obtain an effective zircon collector by compounding, assembling and saponifying reagents. Finally, high-grade zircon concentrate is obtained through step-by-step enrichment, thereby achieving accurate and efficient recovery of zircon. The ZrO2 grade in the zircon concentrate is 55.63% and the recovery rate is 60.82%. The present invention overcomes the technical difficulties of low zircon recovery rate (weak magnetism) and dissociation and recovery of fine-grained zircon in the complex mineral system of alkaline rock-type rare earth ores, laying the foundation for the efficient enrichment and economic utilization of zircon in such deposits. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a flow chart of the method for separating and enriching zirconium minerals from alkaline rock-type rare earth ores. DETAILED DESCRIPTION

[0032] The present invention provides a method for separating and enriching zirconium minerals from alkaline rock-type rare earth ores, comprising the following steps:

[0033] The alkaline rock type rare earth ore is crushed and finely ground in sequence to obtain ore powder, wherein the mass proportion of -200 mesh particles in the ore powder is 85-95%;

[0034] The ore powder is mixed with water to obtain a first slurry; ammonium bicarbonate is added to the first slurry, and the mixture is stirred; sodium silicate is then added, and the mixture is stirred; then, a collector A solution and kerosene are added, the mixture is stirred continuously, and aeration flotation is performed to obtain a rare earth niobium mixed concentrate and flotation tailings;

[0035] The flotation tailings are blended into a second slurry; the second slurry is subjected to a shaking table gravity separation to obtain a shaking table gravity separation concentrate and a shaking table gravity separation tailings;

[0036] The shaking table gravity separation tailings are mixed into a third pulp; the third pulp is subjected to superconducting strong magnetic separation to obtain a magnetic product and a non-magnetic product;

[0037] combining the shaker gravity separation concentrate and the magnetic product to prepare a fourth slurry;

[0038] Ultrafine grinding the fourth slurry to obtain a fifth slurry; the mass proportion of -400 mesh ore particles in the fifth slurry is 85-95%; caustic starch is added to the fifth slurry, stirred, and the collector B solution and the collector C solution are continuously added, and aeration is performed to perform microbubble flotation roughing to obtain a zircon roughing concentrate and a zircon roughing tailings;

[0039] The zircon roughing concentrate is poured into a flotation machine, filled with micro-nano bubbles for micro-bubble flotation selection to obtain a selected zircon concentrate and selected tailings; the selected tailings are returned to the flotation roughing selection;

[0040] The zircon rougher tailings are subjected to centrifugal gravity separation to obtain centrifugal gravity separation concentrate and centrifugal gravity separation tailings;

[0041] combining the centrifugal gravity concentrate and the selected zircon concentrate to obtain a final zircon concentrate;

[0042] The preparation method of the collector A solution comprises the following steps: mixing refined tall oil, phthalic acid and p-tert-butylbenzohydroxamic acid in a mass ratio of 1:(1-2):1 to obtain collector A; mixing the collector A with a 0.5-5 wt% NaOH solution and performing saponification to obtain a collector A solution, wherein the mass fraction of the collector A solution is 1-6%;

[0043] The preparation method of the collector B solution comprises the following steps: mixing 2-ethylhexyl phosphate and coconut oil fatty acid in a mass ratio of (1-3):1 to obtain collector B; mixing the collector B with a 0.5-5 wt% NaOH solution and saponifying the mixture to obtain a collector B solution, wherein the mass fraction of the collector B solution is 1-6%;

[0044] The preparation method of the collector C solution comprises the following steps: mixing arsenazo III and bis(2,4,4-trimethylpentyl)phosphonic acid) in a mass ratio of 1:(2-4) to achieve agent assembly to obtain collector C; mixing the collector C with 0.5-5wt% NaOH solution for saponification to obtain collector C solution, wherein the mass fraction of the collector C solution is 1-6%.

[0045] The invention crushes and finely grinds alkaline rock type rare earth ore in sequence to obtain ore powder, wherein the mass proportion of -200 mesh particles in the ore powder is 85-95%.

[0046] The present invention has no special requirements on the source and composition of the alkaline rock type rare earth ore, and any alkaline rock type rare earth ore well known in the art can be used.

[0047] The present invention preferably adopts jaw crusher and high pressure roller mill to carry out the said crushing. In the present invention, the particle size of the crushed ore obtained after the said crushing is preferably -2mm.

[0048] In the present invention, the fine grinding is preferably performed by a ceramic ball mill. The present invention utilizes a ceramic ball mill for fine grinding. The ceramic medium can reduce Fe contamination on the surface of gangue minerals and avoid affecting the quality of zircon concentrate.

[0049] After obtaining the ore powder, the present invention mixes the ore powder with water to obtain a first slurry; adds ammonium bicarbonate to the first slurry, stirs, then adds sodium silicate, stirs, then adds collector A solution and kerosene, continues stirring, and performs aeration flotation to obtain a rare earth niobium mixed concentrate and flotation tailings.

[0050] In the present invention, the mass concentration of the first slurry is preferably 15-55%, and the temperature is preferably 10-40° C. In the present invention, the ore powder is preferably added to the flotation machine, and then water is added to prepare the first slurry.

[0051] In the present invention, the amount of ammonium bicarbonate added is preferably 500-1000 g / t (referring to the amount of ammonium bicarbonate used per ton of ore), more preferably 600-900 g / t, and even more preferably 700-800 g / t. In the present invention, the ammonium bicarbonate acts as a conditioning agent, combining with impurity ions (such as Ca, Fe, and Ba) on the surface of the minerals in the slurry to adjust and optimize the flotation environment. After adding the ammonium bicarbonate, the mixture is preferably stirred for 1-5 minutes.

[0052] In the present invention, the amount of sodium silicate added is preferably 1500-2500 g / t, more preferably 1700-2300 g / t, and even more preferably 1900-2100 g / t. In the present invention, the sodium silicate inhibits the growth of silicate minerals such as quartz, feldspar, and zircon, and enhances the dispersion of fine particles in the slurry. After adding the sodium silicate, the mixture is preferably stirred for 1-5 minutes.

[0053] In the present invention, the amount of the collector A solution added is preferably 500-800 g / t, more preferably 550-750 g / t, and even more preferably 600-700 g / t, based on the amount of collector A. In the present invention, the method for preparing the collector A solution comprises the following steps: mixing refined tall oil, phthalic acid, and p-tert-butylbenzohydroxamic acid in a mass ratio of 1:(1-2):1 to obtain collector A; and mixing the collector A with a 0.5-5 wt% NaOH solution for saponification to obtain a collector A solution, wherein the mass fraction of the collector A solution is 1-6%.

[0054] In the present invention, the collector A mainly collects rare earth minerals and niobium minerals, including daphnia, bastnaesite, monazite, niobium iron ore-niobium manganese ore, pyrochlore, yttrium niobite and the like.

[0055] In the present invention, the amount of kerosene added is preferably 100-300 g / t, more preferably 150-250 g / t. In the present invention, the kerosene serves as an auxiliary collector. After adding the collector A solution and kerosene, stirring is preferably continued for 1-5 minutes.

[0056] The present invention has no special requirements for the aeration flotation process, and a flotation process well known in the art can be used. In the present invention, after flotation, rare earth niobium mixed concentrate and flotation tailings are obtained; the useful minerals in the flotation tailings are mainly zircon.

[0057] After obtaining the flotation tailings, the present invention prepares the flotation tailings into a second slurry; and performs shaking table gravity separation on the second slurry to obtain shaking table gravity separation concentrate and shaking table gravity separation tailings.

[0058] The second slurry is preferably prepared by thickening or adding water. In the present invention, the mass concentration of the second slurry is preferably 15-30%.

[0059] In the present invention, the inclination angle of the shaking table during the shaking table gravity separation is preferably 2 to 10 degrees, more preferably 4 to 8 degrees, and even more preferably 5 to 6 degrees. In the present invention, the second slurry is preferably poured evenly into the feeding end of the shaking table, and a shaking table gravity separation concentrate (non-magnetic zircon) and a shaking table gravity separation tailings are obtained at the concentrate and tailings ends, respectively. In the present invention, the shaking table gravity separation concentrate is mainly composed of zircon and a small amount of gangue minerals such as quartz associated with zircon, and the tailings are mainly composed of poor intergrowths of fine-grained zircon and gangue minerals.

[0060] After obtaining the shaking table gravity separation tailings, the present invention prepares the shaking table gravity separation tailings into a third ore pulp; and performs superconducting strong magnetic separation on the third ore pulp to obtain magnetic products and non-magnetic products.

[0061] In the present invention, the third slurry is preferably prepared by thickening or adding water. In the present invention, the mass concentration of the third slurry is preferably 10-20%.

[0062] In the present invention, the background magnetic induction intensity of the superconducting high-intensity magnetic separation is preferably 4-5 T. The present invention preferably performs the superconducting high-intensity magnetic separation in a horizontal superconducting magnetic separator, and the magnetic medium is preferably a steel rod with a diameter of preferably 1-2 mm. The present invention preferably feeds the third slurry into the superconducting high-intensity magnetic separator at a uniform speed to obtain a magnetic product and a non-magnetic product, respectively. The magnetic product is primarily composed of weakly magnetic zircon and a small amount of weakly magnetic or zircon-associated gangue minerals; the non-magnetic product is primarily composed of minerals such as quartz, albite, potassium feldspar, and aegirine.

[0063] In the present invention, the shaker gravity separation concentrate and the magnetic product are combined to form a fourth pulp. In the present invention, the fourth pulp is preferably obtained by thickening. In the present invention, the mass concentration of the fourth pulp is preferably 40-60%.

[0064] After obtaining the fourth ore pulp, the present invention performs ultrafine grinding on the fourth ore pulp to obtain a fifth ore pulp, wherein the mass proportion of -400 mesh ore particles in the fifth ore pulp is 85-95%.

[0065] In the present invention, the ultrafine grinding is preferably carried out in a stirred mill. In the present invention, zirconium balls with a volume of 1 to 1.5 times the volume of the slurry are preferably added as grinding media, and the speed of the stirred mill is adjusted to 1000 to 2000 r / min.

[0066] After obtaining the fifth ore pulp, the present invention preferably adds caustic starch to the fifth ore pulp, stirs, continues to add collector B solution and collector C solution, and aerates to perform microbubble flotation roughing to obtain zircon roughing concentrate and zircon roughing tailings.

[0067] In the present invention, the amount of caustic starch added is preferably 400-600 g / t, more preferably 450-550 g / t. In the present invention, the caustic starch serves as a suppressor for gangue minerals such as natrona. After adding the caustic starch, the mixture is preferably stirred for 1-5 minutes.

[0068] In the present invention, the amount of the collector B solution added is preferably 2000-4000 g / t, more preferably 2500-3500 g / t, and further preferably 2700-3100 g / t, based on the amount of collector B. In the present invention, the preparation method of the collector B solution comprises the following steps: mixing 2-ethylhexyl phosphate and coconut oil fatty acid in a mass ratio of (1-3):1 to obtain collector B; mixing the collector B with 0.5-5wt% NaOH solution and saponifying to obtain a collector B solution, wherein the mass fraction of the collector B solution is 1-6%. In the present invention, the function of the collector B is to selectively bind to the zircon in the ore, thereby improving the surface hydrophobicity of the zircon and achieving the purpose of flotation enrichment.

[0069] In the present invention, the amount of the collector C solution added is preferably 1000 g / t, calculated as the amount of collector C. In the present invention, the method for preparing the collector C solution comprises the following steps: mixing arsenazo III and bis(2,4,4-trimethylpentyl)phosphonic acid) in a mass ratio of 1:(2-4) to achieve reagent assembly, thereby obtaining collector C; and mixing the collector C with a 0.5-5wt% NaOH solution for saponification, thereby obtaining a collector C solution, wherein the mass fraction of the collector C solution is 1-6%. In the present invention, a portion of the collector C combines with the collector B to indirectly enhance the hydrophobicity of target minerals such as zircon, while the other portion can also be directly adsorbed on the zircon surface to achieve synergistic capture.

[0070] After adding the collector B solution and the collector C solution, the present invention preferably stirs for 1 to 5 minutes.

[0071] The present invention has no special requirements for the aeration-based microbubble flotation roughing process; any microbubble flotation process known in the art can be employed. In the present invention, the microbubble flotation roughing is preferably performed in a micro-nano bubble generating device, such as a Venturi tube. In the present invention, the microbubble flotation roughing duration is preferably 3 to 6 minutes. After the microbubble flotation roughing, the present invention produces a zircon rougher concentrate and a zircon rougher tailings. The rougher concentrate is initially enriched in zircon; the rougher tailings also contain a small amount of zircon that is relatively coarse and difficult to float.

[0072] The invention pours the zircon roughing concentrate into a flotation machine, fills it with micro-nano bubbles and performs micro-bubble flotation selection to obtain selected zircon concentrate and selected tailings; and the selected tailings are returned to the flotation roughing machine.

[0073] In the present invention, 0-400 g / t of caustic starch is preferably added during the microbubble flotation process. After adding the caustic starch, the process is preferably stirred for 1-5 minutes before infusing the ore with micro-nano bubbles for microbubble flotation. In the present invention, the caustic starch is used to suppress iron-containing gangue minerals. When the caustic starch dosage is zero, it is suitable for ore without iron-containing gangue minerals. After microbubble flotation, the present invention produces a concentrated zircon concentrate and concentrated tailings.

[0074] The invention conducts centrifugal gravity separation on the zircon roughing tailings to obtain centrifugal gravity separation concentrate and centrifugal gravity separation tailings.

[0075] In the present invention, the centrifugal gravity separation conditions preferably include: a centrifugal concentrator speed of 90-120G and a flushing water pressure of 50-70kPa. In the present invention, the centrifugal gravity separation is preferably performed in a Nelson centrifugal concentrator. The zircon rougher tailings are preferably uniformly poured into the feed end of the Nelson centrifugal concentrator, where the fine zircon is enriched in the centrifugal cone to produce a centrifugal gravity concentrate and centrifugal gravity tailings.

[0076] The present invention combines the centrifugal gravity separation concentrate and the selected zircon concentrate to obtain the final zircon concentrate; and combines the non-magnetic product and the centrifugal gravity separation tailings to obtain the final tailings.

[0077] This invention recovers zircon from rare earth and niobium flotation tailings by preferentially flotating rare earth and niobium minerals. It uses a "superconducting strong magnetic separation + shaking table gravity separation" method to initially enrich weakly magnetic and non-magnetic zircon. Through an "ultrafine grinding-microbubble flotation-centrifugal gravity separation" process, the compounding, assembly, and saponification of reagents are used to produce an effective zircon collector. Finally, high-grade zircon concentrate is enriched in stages, achieving precise and efficient zircon recovery. The zircon concentrate has a ZrO2 grade of 55.63% and a recovery rate of 60.82%. This invention overcomes the technical difficulties of low (weakly magnetic) zircon recovery and the dissociation and recovery of fine-grained zircon in complex mineral systems of alkaline rock-type rare earth ores.

[0078] The method for separating and enriching zirconium minerals from alkaline rock-type rare earth ores provided by the present invention is described in detail below with reference to the examples, but they should not be construed as limiting the scope of protection of the present invention.

[0079] Example 1

[0080] The Barzhe deposit (801 mine) in Inner Mongolia is a super-large rare earth, uranium, niobium, and zirconium polymetallic paragenesis. Its main useful minerals are hydroxysilicon beryllium yttrium cerium ore (Xingan stone), zircon, columbite, fluorocarbon cerium ore, monazite, and zinc heliotropes. The main gangue minerals are quartz, potassium feldspar, and sodium iron amphibole. The ore contains 0.95% REO, 3.32% ZrO₂, 0.38% Nb₂O₅, and 0.016% U, respectively.

[0081] Select 1000g of ore Figure 1 The test was carried out under the process flow shown.

[0082] (1) Ore crushing and grinding:

[0083] a. Use jaw crusher and high pressure roller grinding mill to crush the ore into -2mm in steps;

[0084] b. Use ceramic ball mill to further grind the ore to -200 mesh particles with a mass ratio of 90%.

[0085] (2) Preparation of flotation slurry: Pour the finely ground ore into the flotation machine, add water to adjust the slurry concentration to 30%, and the slurry temperature to 30°C, which is recorded as the first slurry.

[0086] (3) Preparation of collector:

[0087] a. Refined tall oil, phthalic acid, and p-tert-butylbenzohydroxamic acid were mixed in a mass ratio of 1:1:1 to obtain a collector A, which was saponified with a 5wt% NaOH solution to obtain a 2% collector A solution;

[0088] b. 2-ethylhexyl phosphate and coconut fatty acid were mixed in a mass ratio of 2:1 to obtain collector B, and saponified with 5wt% NaOH solution to obtain a mass fraction of 2% collector B solution;

[0089] c. Arsenazo III and AD 290 (bis(2,4,4-trimethylpentyl)phosphonic acid) were mixed in a mass ratio of 1:2 and stirred thoroughly to achieve reagent assembly to obtain collector C, which was saponified with a 5wt% NaOH solution to obtain a 2% mass fraction of collector C solution.

[0090] (4) Prioritize flotation of rare earth and niobium minerals:

[0091] a. Add 600g / t ammonium bicarbonate as a conditioning agent to the first slurry and stir for 2min;

[0092] b. Add 2000g / t sodium silicate as an inhibitor and dispersant to the first slurry and stir for 2min;

[0093] c. Add 600 g / t collector A solution (based on the amount of collector A) and 200 g / t kerosene as an auxiliary collector to the first slurry and stir for 3 min;

[0094] d. Aeration flotation to obtain rare earth niobium mixed concentrate and tailings.

[0095] (5) Shaking table gravity separation to recover non-magnetic zircon

[0096] a. Adjust the mass concentration of the rare earth niobium flotation tailings slurry to 20% by thickening or adding water, and record it as the second slurry;

[0097] b. Adjust the inclination angle of the shaking table by 5° and pour the second slurry evenly into the feeding end of the shaking table. At the concentrate end and the tailing end, obtain the shaking table gravity separation concentrate (non-magnetic zircon) and shaking table gravity separation tailings respectively.

[0098] (6) Superconducting strong magnetic separation to recover weakly magnetic zircon:

[0099] a. Adjust the ore mass concentration in the shaker gravity separation tailings to 15% by thickening or adding water to obtain the third slurry;

[0100] b. Adjust the background magnetic induction intensity of the horizontal superconducting magnetic separator to 5T and use steel rods (diameter 1.5mm) as the magnetic medium;

[0101] c. The third slurry is fed into the superconducting high-intensity magnetic separator at a uniform speed to obtain magnetic products and non-magnetic products respectively.

[0102] (7) Ultrafine grinding:

[0103] a. The step (4) in which the shaker concentrate is re-selected and the magnetic product (weakly magnetic zircon) is combined to obtain a slurry having an ore mass concentration of 40% by concentration, referred to as the fourth slurry;

[0104] b. Add the slurry obtained in the previous step to the stirred mill, add 1.5 times the volume of the slurry as zirconium balls as the grinding medium, adjust the stirred mill speed to 1500r / min, and grind the ore to -400 mesh, accounting for 90%, to obtain the fifth slurry.

[0105] (8) Flotation of zircon:

[0106] a. Take the fifth slurry obtained in the previous step and pour it into the flotation machine, and generate micro-nano bubbles through a micro-nano bubble generating device (in this case, a Venturi tube is used, the same below);

[0107] b. Add 500g / t caustic starch to the slurry as a gangue mineral inhibitor such as sodium iron amphibole and stir for 2 minutes;

[0108] c. Add 3000g / t of collector B solution (based on the amount of collector B) to the slurry and stir for 3min; add 1000g / t of collector C solution (based on the amount of collector C) and stir for 3min;

[0109] d. Aeration flotation for 4 minutes to obtain zircon roughing concentrate and zircon roughing tailings.

[0110] (9) The zircon roughing concentrate obtained in the previous step is poured into a flotation machine, 200 g / t of caustic starch is added, and after stirring for 3 minutes, micro-nano bubble flotation is performed to obtain a selected zircon concentrate and selected tailings, and the selected tailings are returned to the roughing.

[0111] (10) Zircon roughing tailings centrifugal gravity separation:

[0112] a. Adjust the speed of the Nielsen centrifugal concentrator to 100G and the flushing water pressure to 70kPa;

[0113] b. Pour the zircon roughing tailings evenly into the feed end of the Nelson centrifugal concentrator. Fine zircon is enriched in the centrifugal cone to obtain centrifugal gravity separation concentrate, and at the same time, the centrifugal gravity separation tailings product is obtained.

[0114] (11) Product merging: combining the centrifugal gravity concentrate and the selected zircon concentrate in step (8) to obtain the final zircon concentrate.

[0115] The test results of Example 1 are shown in Table 1.

[0116] Table 1 Test results of Example 1 (%)

[0117]

[0118] Comparative Example 1

[0119] The same ore sample as in Example 1 was selected to compare the effect of preferential flotation of the original ore tailings with that of Example 1 and only gravity separation to recover the zircon concentrate.

[0120] (1) Ore crushing and grinding:

[0121] a. Use jaw crusher and high pressure roller grinding mill to crush the ore into -2mm in steps;

[0122] b. Use ceramic ball mill to further grind the ore to -200 mesh particles with a mass ratio of 90%.

[0123] (2) Preparation of flotation slurry: Pour the finely ground ore into the flotation machine, add water to adjust the slurry concentration to 30%, and the slurry temperature to 30°C, which is recorded as the first slurry.

[0124] (3) Preparation of collector:

[0125] a. Refined tall oil, phthalic acid, and p-tert-butylbenzohydroxamic acid were mixed in a mass ratio of 1:1:1 to obtain a collector A, which was saponified with a 5wt% NaOH solution to obtain a 2% collector A solution;

[0126] b. 2-ethylhexyl phosphate and coconut fatty acid were mixed in a mass ratio of 2:1 to obtain collector B, which was saponified with 5 wt % NaOH solution to obtain a 2% collector B solution.

[0127] c. Arsenazo III and AD 290 (bis(2,4,4-trimethylpentyl)phosphonic acid) were mixed in a mass ratio of 1:2 and stirred thoroughly to achieve reagent assembly to obtain collector C, which was saponified with a 5wt% NaOH solution to obtain a 2% mass fraction of collector C solution.

[0128] (4) Prioritize flotation of rare earth and niobium minerals:

[0129] a. Add 600g / t ammonium bicarbonate as a conditioning agent to the first slurry and stir for 2min;

[0130] b. Add 2000g / t sodium silicate as an inhibitor and dispersant to the first slurry and stir for 2min;

[0131] c. Add 600 g / t collector A solution (based on the amount of collector A) and 200 g / t kerosene as an auxiliary collector to the first slurry and stir for 3 min;

[0132] d. Aeration flotation to obtain rare earth niobium mixed concentrate and tailings.

[0133] (5) Shaking table gravity separation to recover non-magnetic zircon

[0134] a. Adjust the mass concentration of the rare earth niobium flotation tailings slurry to 20% by thickening or adding water, and record it as the second slurry;

[0135] b. Adjust the inclination angle of the shaking table by 5° and pour the second slurry evenly into the feeding end of the shaking table. At the concentrate end and the tailing end, obtain the shaking table gravity separation concentrate (non-magnetic zircon) and shaking table gravity separation tailings respectively.

[0136] The test results of Comparative Example 1 are shown in Table 2.

[0137] Table 2 Test results of comparative example 1 (%)

[0138]

[0139] Example 2

[0140] The Bozigoer super-large REE-Nb-Ta-Zr deposit is located in Baicheng County, Aksu City, Xinjiang, my country. It is a super-large alkaline granite-type rare earth deposit. The main valuable elements in the deposit are REO (0.124%), Nb2O5 (0.08%), Ta2O5 (0.006%), and ZrO2 (0.22%). The ore minerals are mainly pyrochlore, followed by zircon, monazite, xenotime, thorite, calcium-silicate thorite, calcium-silicate zircon, etc. The gangue minerals are mainly albite, microcline, and quartz, with a small amount of nepheline, sodium amphibole and trace amounts of ilmenite, magnetite, apatite, etc.

[0141] Select 500g of ore Figure 1 The test was carried out under the process flow shown.

[0142] (1) Ore crushing and grinding:

[0143] a. Use jaw crusher and high pressure roller grinding mill to crush the ore into -2mm in steps;

[0144] b. Use ceramic ball mill to further grind the ore to -200 mesh particles with a mass ratio of 95%.

[0145] (2) Preparation of flotation slurry: Pour the finely ground ore into the flotation machine, add water to adjust the slurry concentration to 40% and the slurry temperature to 35°C, which is recorded as the first slurry.

[0146] (3) Preparation of collector:

[0147] a. Refined tall oil, phthalic acid, and p-tert-butylbenzohydroxamic acid were mixed in a mass ratio of 1:2:1 to obtain a collector A, which was saponified with a 5wt% NaOH solution to obtain a 2% collector A solution;

[0148] b 2-ethylhexyl phosphate, coconut fatty acid in a mass ratio of 3: 1 ratio to obtain collector B, saponified with 5wt% NaOH solution to obtain a mass fraction of 2% collector B solution;

[0149] c. Arsenazo III and AD 290 (bis(2,4,4-trimethylpentyl)phosphonic acid) were mixed in a mass ratio of 1:4 and stirred thoroughly to assemble the reagent to obtain Collector C, which was saponified with a 5wt% NaOH solution to obtain a 2% mass fraction of Collector C solution.

[0150] (4) Prioritize flotation of rare earth and niobium minerals:

[0151] a. Add 1000g / t ammonium bicarbonate as a conditioning agent to the first slurry and stir for 2 minutes;

[0152] b. Add 1500g / t sodium silicate as an inhibitor and dispersant to the first slurry and stir for 2min;

[0153] c. Add 800 g / t collector A solution (based on the amount of collector A) and 100 g / t kerosene as an auxiliary collector to the first slurry and stir for 3 min;

[0154] d. Aeration flotation to obtain rare earth niobium mixed concentrate and tailings.

[0155] (5) Shaking table gravity separation to recover non-magnetic zircon

[0156] a. Adjust the mass concentration of the rare earth niobium flotation tailings slurry to 15% by thickening or adding water, and record it as the second slurry;

[0157] b. Adjust the inclination angle of the shaking table to 3°, and evenly pour the rare earth niobium flotation tailings slurry into the feeding end of the shaking table. At the concentrate and tailings ends, obtain the shaking table gravity separation concentrate (non-magnetic zircon) and shaking table gravity separation tailings respectively.

[0158] (6) Superconducting strong magnetic separation to recover weakly magnetic zircon:

[0159] a. Adjust the ore mass concentration of the shaker gravity separation tailings to 10% by thickening or adding water to obtain the third slurry;

[0160] b. Adjust the background magnetic induction intensity of the horizontal superconducting magnetic separator to 5T and use steel rods (1mm diameter) as the magnetic medium;

[0161] c. Feed the third slurry into the superconducting high-intensity magnetic separator at a uniform speed to obtain magnetic products and non-magnetic products respectively.

[0162] (7) Ultrafine grinding:

[0163] a. The step (4) in which the shaker concentrate is re-selected and the magnetic product (weakly magnetic zircon) is combined to obtain a slurry having an ore mass concentration of 50% by concentration, referred to as the fourth slurry;

[0164] b. Add the slurry obtained in the previous step to the stirred mill, add zirconium balls with a volume of 1 times the slurry as the grinding medium, adjust the stirred mill speed to 1200r / min, and grind the ore to -400 mesh with a proportion of 85% to obtain the fifth slurry.

[0165] (8) Flotation of zircon:

[0166] a. Take the fifth slurry obtained in the previous step and pour it into the flotation machine, and generate micro-nano bubbles through a micro-nano bubble generating device (in this case, a Venturi tube is used, the same below);

[0167] b. Add 600g / t caustic starch to the slurry as a inhibitor of gangue minerals such as sodium iron amphibole and stir for 2 minutes;

[0168] c. Add 2000g / t of collector B solution (based on the amount of collector B) to the slurry and stir for 3 minutes; add 1000g / t of collector C solution (based on the amount of collector C) and stir for 3 minutes;

[0169] d. Aeration flotation for 5 minutes to obtain zircon roughing concentrate and tailings.

[0170] (9) The roughing concentrate obtained in the previous step is poured into a flotation machine, 300 g / t of caustic starch is added, and after stirring for 3 minutes, micro-nano bubble flotation is performed to obtain a selected zircon concentrate and selected tailings. The selected tailings are returned to the roughing.

[0171] (10) Zircon roughing tailings centrifugal gravity separation:

[0172] a. Adjust the speed of the Nelson centrifugal concentrator to 90G and the flushing water pressure to 60kPa;

[0173] b. Pour the zircon roughing tailings evenly into the feed end of the Nelson centrifugal concentrator. Fine zircon is enriched in the centrifugal cone to obtain centrifugal gravity separation concentrate, and at the same time, the centrifugal gravity separation tailings product is obtained.

[0174] (11) Product merging: combining the centrifugal gravity concentrate and the selected zircon concentrate in step (8) to obtain the final zircon concentrate.

[0175] The test results of Example 2 are shown in Table 3.

[0176] Table 3 Test results of Example 2 (%)

[0177]

[0178]

[0179] It can be seen from the above embodiments and comparative examples that the present invention recovers zircon from rare earth niobium flotation tailings by preferentially flotating rare earth and niobium minerals; adopts the "superconducting strong magnetic separation + shaking table gravity separation" method to preliminarily enrich weakly magnetic zircon and non-magnetic zircon; through the "ultrafine grinding-microbubble flotation-centrifugal gravity separation" method, a zircon collector with good effect is obtained by reagent compounding, assembly, and saponification, and finally a high-grade zircon concentrate is obtained by step-by-step enrichment, thereby realizing accurate and efficient recovery of zircon.

[0180] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for separating and enriching zirconium minerals from alkaline rock-type rare earth ores, characterized in that: The following steps are involved: The alkaline rock type rare earth ore is crushed and finely ground in sequence to obtain ore powder, wherein the mass proportion of -200 mesh particles in the ore powder is 85-95%; The ore powder is mixed with water to obtain a first slurry; ammonium bicarbonate is added to the first slurry, and the mixture is stirred; sodium silicate is then added, and the mixture is stirred; then, a collector A solution and kerosene are added, the mixture is stirred continuously, and aeration flotation is performed to obtain a rare earth niobium mixed concentrate and flotation tailings; The flotation tailings are blended into a second slurry; the second slurry is subjected to a shaking table gravity separation to obtain a shaking table gravity separation concentrate and a shaking table gravity separation tailings; The shaking table gravity separation tailings are mixed into a third pulp; the third pulp is subjected to superconducting strong magnetic separation to obtain a magnetic product and a non-magnetic product; The shaker gravity separation concentrate and the magnetic product are combined to prepare a fourth slurry; the fourth slurry is subjected to ultrafine grinding to obtain a fifth slurry; the mass proportion of -400 mesh ore particles in the fifth slurry is 85-95%; adding caustic starch to the fifth slurry, stirring, continuing to add collector B solution and collector C solution, aerating and performing microbubble flotation roughing to obtain zircon roughing concentrate and zircon roughing tailings; The zircon roughing concentrate is poured into a flotation machine, filled with micro-nano bubbles for micro-bubble flotation selection to obtain a selected zircon concentrate and selected tailings; the selected tailings are returned to the flotation roughing selection; The zircon rougher tailings are subjected to centrifugal gravity separation to obtain centrifugal gravity separation concentrate and centrifugal gravity separation tailings; combining the centrifugal gravity concentrate and the selected zircon concentrate to obtain a final zircon concentrate; The preparation method of the collector A solution comprises the following steps: mixing refined tall oil, phthalic acid and p-tert-butylbenzohydroxamic acid in a mass ratio of 1:(1-2):1 to obtain collector A; mixing the collector A with a 0.5-5 wt% NaOH solution and performing saponification to obtain a collector A solution, wherein the mass fraction of the collector A solution is 1-6%; The preparation method of the collector B solution comprises the following steps: mixing 2-ethylhexyl phosphate and coconut oil fatty acid in a mass ratio of (1-3):1 to obtain collector B; mixing the collector B with a 0.5-5 wt% NaOH solution and saponifying the mixture to obtain a collector B solution, wherein the mass fraction of the collector B solution is 1-6%; The preparation method of the collector C solution comprises the following steps: mixing arsenazo III and bis(2,4,4-trimethylpentyl)phosphonic acid) in a mass ratio of 1:(2-4) to achieve agent assembly to obtain collector C; mixing the collector C with 0.5-5wt% NaOH solution for saponification to obtain collector C solution, wherein the mass fraction of the collector C solution is 1-6%.

2. The method according to claim 1, characterized in that The mass concentration of the first slurry is 15-55%, and the temperature is 10-40°C.

3. The method according to claim 1, characterized in that The amount of ammonium bicarbonate added is 500-1000 g / t; the amount of sodium silicate added is 1500-2500 g / t; the amount of collector A solution added is 500-800 g / t based on the amount of collector A; and the amount of kerosene added is 100-300 g / t.

4. The method according to claim 1, wherein The mass concentration of the second slurry is 15-30%; the inclination angle of the shaking table during gravity separation is 2-10°.

5. The method according to claim 1, wherein The mass concentration of the third slurry is 10-20%.

6. The method according to claim 1 or 5, characterized in that The background magnetic induction intensity of the superconducting strong magnetic separation is 4 to 5T.

7. The method according to claim 1, characterized in that The mass concentration of the fourth slurry is 40-60%.

8. The method according to claim 1, characterized in that The added amount of the caustic starch is 400-600 g / t; the added amount of the collector B solution is 2000-4000 g / t based on the amount of collector B; and the added amount of the collector C solution is 1000 g / t based on the amount of collector C.

9. The method according to claim 1, characterized in that The conditions for the centrifugal gravity separation include: a centrifugal concentrator speed of 90 to 120 G, and a flushing water pressure of 50 to 70 kPa.

10. The method according to claim 1, characterized in that During the microbubble flotation selection, 0 to 400 g / t of caustic starch is added.

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