A mineral processing method for upgrading and reducing impurities in rare earth ores

Abstract

This invention relates to a mineral processing method for improving the quality and reducing impurities of rare earth ore, belonging to the field of rare earth ore technology. It addresses the problem of low grade and high content of harmful impurities in rare earth concentrates obtained from iron ore tailings using existing processes. The method includes: a primary roughing process to obtain a roughing concentrate and roughing tailings; the roughing concentrate is then subjected to two subsequent cleaning processes; the first inhibitor is saline water glass, and the first rare earth collector includes 1-alkoxy-2-naphthylhydroxyxamic acid and oxidized paraffin soap; the second-cleaned concentrate is ground and then slurried with water to adjust the pH to 4-6.5; a fourth inhibitor, a fourth rare earth collector, and a fourth frother are then added sequentially for a second roughing process to obtain a second roughing concentrate and second roughing tailings; the second roughing concentrate is then subjected to a primary cleaning process to obtain a rare earth concentrate and rare earth middlings, with the rare earth middlings being returned to the second roughing process; the fourth inhibitor includes nitric acid triacetic acid and fulvic acid. This method can improve the grade of rare earth concentrates and reduce the impurity content.

Description

Technical Field

[0001] This invention relates to the field of rare earth mineral technology, and in particular to a mineral processing method for improving the quality and reducing impurities of rare earth minerals. Background Technology

[0002] The Bayan Obo mine is a world-class super-large polymetallic deposit containing iron, rare earth elements, fluorite, and other minerals. Rare earth minerals are found in the tailings after iron ore beneficiation at Bayan Obo. Therefore, it is necessary to recover rare earth minerals from these tailings. Current flotation processes yield rare earth concentrates with a rare earth grade of only 50%-58%, indicating low rare earth content and high levels of harmful impurities such as Ca, F, and P. Improving the grade of rare earth concentrates and reducing impurity content is of great significance for enhancing the utilization rate of rare earth resources and achieving clean metallurgy of rare earth concentrates. Summary of the Invention

[0003] Based on the above analysis, the present invention aims to provide a mineral processing method for improving the quality and reducing impurities of rare earth ore, in order to solve one of the following technical problems: the rare earth concentrate obtained by the existing flotation process from iron tailings has low rare earth grade and high content of harmful impurities.

[0004] On the one hand, the present invention provides a mineral processing method for upgrading and reducing impurities in rare earth ores, the mineral processing method comprising the following steps: Step 1, First roughing: Adjust the pH of the rare earth ore slurry to above 7, and add the first inhibitor, the first rare earth collector, and the first frother in sequence to carry out the first roughing to obtain the roughing concentrate and the roughing tailings; the roughing concentrate is then subjected to two cleaning processes, and the roughing tailings are subjected to one scavenging to obtain the scavenged concentrate and the scavenged tailings; the first inhibitor is saline water glass, and the first rare earth collector includes 1-alkoxy-2-naphthylmethylhydroxamic acid and oxidized paraffin soap; Step 2, First Cleaning: Add the rougher concentrate to the flotation cell, add water to adjust the slurry, and then add the second inhibitor, the second rare earth collector, and the second frother in sequence to carry out the first cleaning, and obtain the first cleaned concentrate and the first cleaned middlings. Step 3, Second Cleaning: Add the primary cleaned concentrate to the flotation cell, add water to adjust the slurry, and then add the third inhibitor, the third rare earth collector and the third frother in sequence for the second cleaning to obtain the secondary cleaned concentrate and the secondary cleaned middlings. The second and third inhibitors have the same composition as the first inhibitor, and the second and third rare earth collectors have the same composition as the first rare earth collector. Step 4, Secondary roughing: After grinding the secondary concentrate, water is added to adjust the slurry to pH 4-6.5. The fourth inhibitor, the fourth rare earth collector, and the fourth frother are added sequentially for secondary roughing to obtain secondary roughing concentrate and secondary roughing tailings. The secondary roughing concentrate is then subjected to primary cleaning to obtain rare earth concentrate and rare earth middlings. The rare earth middlings are returned to the secondary roughing. The fourth inhibitor includes nitric acid triacetic acid and fulvic acid.

[0005] Furthermore, in step 4, the fourth rare earth collector is alkylamine dimethylphosphonic acid, and the dosage of the fourth rare earth collector is 0.5-2.0 kg / t; the fourth foaming agent is methyl isobutyl methanol, and the dosage of the fourth foaming agent is 10-100 g / t.

[0006] Furthermore, in step 1, the mass ratio of 1-alkoxy-2-naphthylhydroxyoxime acid to oxidized paraffin soap in the first rare earth collector is 7-10:1-2.

[0007] Furthermore, in step 1, the mass concentration of the rare earth ore slurry is 45-70%, the pH is adjusted to 7-11, and the temperature of the slurry is 35-75℃.

[0008] Furthermore, in step 1, the amount of the first inhibitor added is 0.5–3.0 kg / t.

[0009] Furthermore, in step 1, the saline water glass is prepared by the following method: water glass is mixed with aluminum salt by stirring; wherein the aluminum salt is one or more of aluminum chloride and aluminum sulfate.

[0010] Furthermore, in step 1, the mass ratio of water glass to aluminum salt is 5:1 to 9:1.

[0011] Furthermore, the first foaming agent is pine oil, with an addition amount of 30-200 g / t.

[0012] Furthermore, in step 4, during the secondary fine concentrate grinding process, steel balls and ceramic media are used as grinding media, with a mass ratio of 3 to 5:1. The fineness after grinding is more than 80% of -200 mesh and more than 70% of -500 mesh.

[0013] Furthermore, in step 4, the mass ratio of nitric acid triacetic acid to fulvic acid in the fourth inhibitor is 5–9:0.5–2.

[0014] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: a) The mineral processing method of the present invention first removes a large amount of silicate gangue minerals by flotation in an alkaline system, while obtaining a secondary concentrate with high recovery rate; the secondary concentrate is regrinded using a vertical mill with a combination of steel balls and ceramic media balls to improve the liberation degree of rare earth minerals while avoiding over-grinding; after regrinding, an acidic flotation system is used to remove a large amount of carbonate gangue minerals, fluorite and apatite, etc., to improve the grade of rare earth concentrate and reduce impurity content.

[0015] (b) In the mineral processing method of the present invention, under the alkaline flotation system, the saline water glass has an excellent inhibitory effect on silicate gangue minerals. The first rare earth collector, which is a combination of 1-alkoxy-2-naphthomic hydroxamic acid and oxidized paraffin soap, not only compensates for the weak collecting ability of hydroxamic acid, but also improves the low selectivity of oxidized paraffin soap. The combination of inhibitor and collector reduces the amount of reagent used and improves the grade and recovery rate of rare earth rough concentrate.

[0016] c) In the mineral processing method of the present invention, under the acidic flotation system, the combined inhibitor of nitrotriacetic acid and fulvic acid synergistically inhibits gangue minerals containing Ca, F, and P such as dolomite, calcite, fluorite, and apatite. Alkylamine dimethylphosphonic acid has a strong collecting ability for rare earth minerals. The combined use of inhibitors and collectors removes a large amount of Ca, F, and P impurities, thereby improving the grade of rare earth concentrate.

[0017] d) The rare earth concentrate obtained by the mineral processing method of the present invention has a high rare earth grade, for example, a rare earth grade of 66% or more, and low contents of Ca, F, and P impurities, for example, CaO content of less than 5%, SiO2 content of less than 0.6%, F content of less than 3.6%, and P content of less than 4.5%. The rare earth recovery rate of the mineral processing method of the present invention is 60% or more.

[0018] e) The method of the present invention uses less reagent, has a simple process, high grade and recovery rate of rare earth concentrate, and low content of impurity elements, and has the potential for large-scale promotion.

[0019] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] Figure 1 This is a process flow diagram of the mineral processing method of the present invention; Figure 2The XRD analysis results are for the rare earth concentrate of Example 1 of the present invention. Detailed Implementation

[0022] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0023] This invention provides a mineral processing method for upgrading and reducing impurities in rare earth ores, comprising the following steps: Step 1, First roughing: Adjust the pH of the rare earth ore slurry to above 7, and add the first inhibitor, the first rare earth collector and the first frother in sequence to carry out the first roughing to obtain the roughing concentrate and the roughing tailings; the roughing concentrate is then subjected to two cleaning processes, and the roughing tailings are subjected to one scavenging to obtain the scavenged concentrate and the scavenged tailings. Step 2, First Cleaning: Add the rougher concentrate to the flotation cell, add water to adjust the slurry, and then add the second inhibitor, the second rare earth collector, and the second frother in sequence to carry out the first cleaning, and obtain the first cleaned concentrate and the first cleaned middlings. Step 3, Second Cleaning: Add the primary cleaned concentrate to the flotation cell, add water to adjust the slurry, and then add the third inhibitor, the third rare earth collector and the third frother in sequence for the second cleaning to obtain the secondary cleaned concentrate and the secondary cleaned middlings. Step 4, Secondary roughing: After grinding the secondary concentrate, water is added to adjust the slurry and the pH is adjusted to below 6.5. Then, the fourth inhibitor, the fourth rare earth collector, and the fourth frother are added in sequence to carry out secondary roughing to obtain secondary roughing concentrate and secondary roughing tailings. The secondary roughing concentrate is then subjected to primary cleaning to obtain rare earth concentrate and rare earth middlings. The rare earth middlings are returned to the secondary roughing.

[0024] Specifically, in step 1 above, the rare earth ore is made from iron tailings. The components of the rare earth ore, by mass percentage, mainly include: rare earth: 6%~13%, CaO: 10%~35%, SiO2: 8%~30%, F: 5%~15%, and P: 0.5%~6%. The main phases in the rare earth ore include silicate gangue minerals, carbonate gangue minerals, fluorite, and apatite.

[0025] Specifically, in step 1 above, considering that both excessively low and excessively high concentrations of rare earth ore slurry are not conducive to mineral flotation, the concentration of rare earth ore slurry is controlled at 45-70%, for example, 45%, 50%, 55%, 60%, 65%, or 70%; preferably, the concentration of rare earth ore slurry is controlled at 50-65%.

[0026] Specifically, in step 1 above, the pH is adjusted to 7-11, for example, 7, 8, 9, 10, or 11.

[0027] Specifically, in step 1 above, considering that excessively high pulp temperature will lead to reagent decomposition, unstable foam, and low concentrate grade, while excessively low temperature will lead to slow reaction, reagent insolubility, and low recovery rate, the pulp temperature is controlled at 35–75℃, for example, 35℃, 40℃, 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, and 75℃.

[0028] Specifically, in step 1 above, the first inhibitor is saline water glass. Considering that if the amount of the first inhibitor added is too high, rare earth minerals will be inhibited and the recovery rate will decrease, while if it is too low, gangue minerals cannot be effectively inhibited, the amount of the first inhibitor added is controlled to be 0.5-3.0 kg / t, for example, 0.5 kg / t, 1 kg / t, 1.5 kg / t, 2 kg / t, 2.5 kg / t, and 3 kg / t.

[0029] Specifically, the aforementioned saline water glass is prepared by the following method: water glass is mixed with aluminum salt by stirring. The aluminum salt is one or more of aluminum chloride and aluminum sulfate. The mass ratio of water glass to aluminum salt is 5:1 to 9:1, for example, 5:1, 6:1, 7:1, 8:1, or 9:1.

[0030] Specifically, in step 1 above, the first rare earth collector includes 1-alkoxy-2-naphthylhydroxamic acid and oxidized paraffin soap. The 1-alkoxy-2-naphthylhydroxamic acid was purchased from Donghui Xingnuo (Changsha) Materials Co., Ltd.

[0031] Specifically, in step 1 above, the mass ratio of 1-alkoxy-2-naphthylhydroxyxamic acid to oxidized paraffin soap in the first rare earth collector is 7-10:1-2, for example 7:1, 7:1.5, 7:2, 8:1, 8:1.5, 8:2, 9:1, 9:1.5, 9:2, 10:1, 10:1.5, 10:2.

[0032] Specifically, in step 1 above, considering that if the amount of the first rare earth collector added is too high, gangue minerals will enter the flotation concentrate, reducing the concentrate grade; if the amount of the first rare earth collector added is too low, the rare earth recovery rate will be too low. Therefore, the amount of the first rare earth collector added is controlled to be 0.5-2 kg / t, for example, 0.5 kg / t, 1 kg / t, 1.5 kg / t, or 2 kg / t.

[0033] Specifically, in step 1 above, the first foaming agent is pine oil, and the amount added is 30-200g / t, for example 30g / t, 50g / t, 70g / t, 100g / t, 130g / t, 150g / t, 180g / t, 200g / t.

[0034] Specifically, in step 1 above, a scavenging collector and a scavenging frother are added during the scavenging process. The scavenging collector has the same composition as the first rare earth collector, and the dosage of the scavenging collector is half that of the first rare earth collector, for example, 0.25-1 kg / t, such as 0.25 kg / t, 0.5 kg / t, 0.7 kg / t, or 1 kg / t. The scavenging frother is pine oil, and the dosage is 15-100 g / t, such as 15 g / t, 30 g / t, 50 g / t, 70 g / t, or 100 g / t.

[0035] Specifically, in step 2 above, the second inhibitor has the same composition as the first inhibitor, the second rare earth collector has the same composition as the first rare earth collector, and the second foaming agent has the same composition as the first foaming agent.

[0036] Specifically, in step 2 above, the dosage of the second inhibitor is half that of the first inhibitor. For example, the dosage of the second inhibitor is 0.25 to 1.5 kg / t, such as 0.25 kg / t, 0.5 kg / t, 1 kg / t, 1.25 kg / t, or 1.5 kg / t.

[0037] Specifically, in step 2 above, the amount of the second rare earth collector is half the amount of the first rare earth collector. For example, the amount of the second rare earth collector is 0.25 to 1 kg / t, such as 0.25 kg / t, 0.5 kg / t, 0.7 kg / t, or 1 kg / t.

[0038] Specifically, in step 2 above, the amount of the second foaming agent is half the amount of the first foaming agent. For example, the amount of the second foaming agent is 15 to 100 g / t, such as 15 g / t, 30 g / t, 50 g / t, 70 g / t, or 100 g / t.

[0039] Specifically, in step 3 above, the third inhibitor has the same composition as the second inhibitor, the third rare earth collector has the same composition as the second rare earth collector, and the third foaming agent has the same composition as the second foaming agent.

[0040] Specifically, in step 3 above, the dosage of the third inhibitor is half that of the second inhibitor. For example, the dosage of the third inhibitor is 0.125 to 0.75 kg / t, such as 0.125 kg / t, 0.2 kg / t, 0.3 kg / t, 0.4 kg / t, 0.5 kg / t, 0.6 kg / t, 0.7 kg / t, or 0.75 kg / t.

[0041] Specifically, in step 3 above, the amount of the third rare earth collector is half that of the second rare earth collector. For example, the amount of the third rare earth collector is 0.25 to 1 kg / t, such as 0.25 kg / t, 0.5 kg / t, 0.7 kg / t, or 1 kg / t.

[0042] Specifically, in step 3 above, the amount of the third foaming agent is half the amount of the second foaming agent. For example, the amount of the third foaming agent is 7.5 to 50 g / t, such as 7.5 g / t, 10 g / t, 20 g / t, 30 g / t, 40 g / t, or 50 g / t.

[0043] Specifically, in steps 1 to 3 above, the middlings from the sweeping, primary and secondary cleaning processes are combined and returned to the primary coarse selection process.

[0044] Specifically, in step 4 above, during the secondary fine concentrate grinding process, a vertical mill is used for grinding, and steel balls and ceramic media are used as grinding media. The mass ratio of steel balls to ceramic media is 3 to 5:1, for example, 3:1, 4:1, or 5:1.

[0045] Specifically, in step 4 above, the fineness of the concentrate after secondary refining is controlled to be above 80% for -200 mesh and above 70% for -500 mesh.

[0046] Specifically, in step 4 above, the mass concentration of the slurry after conditioning is 30-60%, for example, 30%, 40%, 50%, 60%; the pH value is 4-6.5, for example, 4, 5, 6, 6.5; and the slurry temperature is 30-60℃, for example, 30℃, 40℃, 45℃, 50℃, 55℃, 60℃.

[0047] Specifically, in step 4 above, the fourth inhibitor includes nitric acid triacetic acid and fulvic acid, with a mass ratio of nitric acid triacetic acid to fulvic acid of 5–9:0.5–2.

[0048] Specifically, in step 4 above, the dosage of the fourth inhibitor is 0.1 to 1.0 kg / t, for example, 0.1 kg / t, 0.2 kg / t, 0.4 kg / t, 0.5 kg / t, 0.7 kg / t, or 1.0 kg / t.

[0049] Specifically, in step 4 above, the fourth rare earth collector is alkylamine dimethylphosphonic acid, and the dosage of the fourth rare earth collector is 0.5 to 2.0 kg / t, for example, 0.5 kg / t, 0.7 kg / t, 1 kg / t, 1.5 kg / t, 1.7 kg / t, and 2 kg / t.

[0050] Specifically, in step 4 above, the fourth foaming agent is methyl isobutyl methanol, and the amount of the fourth foaming agent is 10 to 100 g / t, for example, 10 g / t, 20 g / t, 30 g / t, 40 g / t, 50 g / t, 60 g / t, 80 g / t, or 100 g / t.

[0051] Specifically, in step 4 above, the step of performing a primary cleaning of the secondary roughing concentrate includes: S401. Add the secondary roughing concentrate to the flotation cell, add water to adjust the slurry, and then add the fifth inhibitor, the fifth rare earth collector and the fifth frother in sequence for fine selection to obtain rare earth concentrate and rare earth middlings.

[0052] Specifically, in S401 above, the fifth inhibitor has the same composition as the fourth inhibitor, the fifth rare earth collector has the same composition as the fourth rare earth collector, and the fifth foaming agent has the same composition as the fourth foaming agent.

[0053] Specifically, in the above S401, the dosage of the fifth inhibitor is half that of the fourth inhibitor. For example, the dosage of the fifth inhibitor is 0.05 to 0.5 kg / t, such as 0.05 kg / t, 0.1 kg / t, 0.2 kg / t, 0.3 kg / t, 0.4 kg / t, or 0.5 kg / t.

[0054] Specifically, in S401 above, the amount of the fifth rare earth collector is half that of the fourth rare earth collector. For example, the amount of the fifth rare earth collector is 0.25 to 1 kg / t, such as 0.25 kg / t, 0.5 kg / t, 0.7 kg / t, or 1 kg / t.

[0055] Specifically, in S401 above, the amount of the fifth foaming agent is half the amount of the fourth foaming agent. For example, the amount of the fifth foaming agent is 5 to 50 g / t, such as 5 g / t, 10 g / t, 20 g / t, 30 g / t, 40 g / t, or 50 g / t.

[0056] Specifically, the rare earth grade in the rare earth concentrate obtained in step 4 above is above 66%, for example, 66.24%~68.5%; the CaO content is below 5%, for example, 3.95%~4.83%; the SiO2 content is below 0.6%, for example, 0.43%~0.57%; the F content is below 3.6%, for example, 3.19%~3.56%; and the P content is below 4.5%, for example, 3.96%~4.41%.

[0057] Specifically, the rare earth recovery rate of the mineral processing method of the present invention is above 60%, for example, 60.89% to 62.18%.

[0058] The mineral processing method of this invention first removes a large amount of silicate gangue minerals by flotation in an alkaline system, while obtaining a secondary concentrate with high recovery rate; the secondary concentrate is regrinded using a vertical mill with a combination of steel balls and ceramic media balls to improve the liberation degree of rare earth minerals while avoiding over-grinding; after regrinding, an acidic flotation system is used to remove a large amount of carbonate gangue minerals, fluorite, and apatite, thereby improving the grade of rare earth concentrate and reducing impurity content.

[0059] In the mineral processing method of this invention, under the alkaline flotation system, the saline water glass has an excellent inhibitory effect on silicate gangue minerals. The first rare earth collector, which is a combination of 1-alkoxy-2-naphthyl hydroxamic acid and oxidized paraffin soap, not only compensates for the weak collecting ability of hydroxamic acid, but also improves the low selectivity of oxidized paraffin soap. The combination of inhibitor and collector reduces the amount of reagents used and improves the grade and recovery rate of rare earth rough concentrate.

[0060] In the mineral processing method of this invention, under the acidic flotation system, the combined inhibitors of nitrotriacetic acid and fulvic acid synergistically inhibit gangue minerals containing Ca, F, and P, such as dolomite, calcite, fluorite, and apatite. Alkylamine dimethylphosphonic acid has a strong collecting ability for rare earth minerals. The combined use of inhibitors and collectors removes a large amount of Ca, F, and P impurities, thereby improving the grade of rare earth concentrate.

[0061] The advantages of the mineral processing method of the present invention will be demonstrated below with specific embodiments and comparative examples.

[0062] Example 1 This embodiment provides a mineral processing method for upgrading and reducing impurities in rare earth ore, including the following steps: Step 1, Primary roughing: The pH of a 60% rare earth ore slurry is adjusted to 9.2, and the slurry temperature is 60℃. The first inhibitor, the first rare earth collector, and the first frother are added sequentially for primary roughing to obtain a roughing concentrate and roughing tailings. The roughing concentrate is then subjected to two subsequent cleaning processes, and the roughing tailings are subjected to a scavenging process to obtain scavenged concentrate and scavenged tailings. The rare earth ore uses iron tailings. The components of the rare earth ore, by mass percentage, mainly include: rare earth: 10.82%, CaO: 21.49%, SiO2: 15.88%, F: 10.47%, P: 1.35%. The main phases in the rare earth ore include silicate gangue minerals, carbonate gangue minerals, fluorite, and apatite. The first inhibitor is water glass, with a dosage of 2.4 kg / t; the first rare earth collector includes 1-alkoxy-2-naphthylhydroxamic acid and oxidized paraffin soap. The 1-alkoxy-2-naphthylhydroxamic acid was purchased from Donghui Xingnuo (Changsha) Materials Co., Ltd., and the mass ratio of 1-alkoxy-2-naphthylhydroxamic acid to oxidized paraffin soap is 7:1.5. The dosage of the first rare earth collector is 0.9 kg / t; the first foaming agent is pine oil, with an addition amount of 120 g / t. A scavenging collector and a scavenging frother are added during the first scavenging process. The composition of the scavenging collector is the same as that of the first rare earth collector. The dosage of the scavenging collector is 0.45 kg / t, and the scavenging frother is pine oil, with an addition amount of 60 g / t. Step 2, First Cleaning: Add the rougher concentrate to the flotation cell, add water to adjust the slurry, and then add the second depressant, the second rare earth collector, and the second frother in sequence for the first cleaning, to obtain the first-cleaned concentrate and the first-cleaned middlings; the second depressant has the same composition as the first depressant, the second rare earth collector has the same composition as the first rare earth collector, and the second frother has the same composition as the first frother; the dosage of the second depressant is 1.2 kg / t, the dosage of the second rare earth collector is 0.45 kg / t, and the dosage of the second frother is 60 g / t; Step 3, Second Cleaning: Add the primary cleaned concentrate to the flotation cell, add water to adjust the slurry, and then add the third depressant, the third rare earth collector, and the third frother in sequence for a second cleaning to obtain a secondary cleaned concentrate and secondary cleaned middlings. The third depressant has the same composition as the first depressant, the third rare earth collector has the same composition as the first rare earth collector, and the third frother has the same composition as the first frother. The dosage of the third depressant is 0.6 kg / t, the dosage of the third rare earth collector is 0.225 kg / t, and the dosage of the third frother is 30 g / t. Step 4, Secondary roughing: After grinding the secondary concentrate, water is added to adjust the slurry and the pH is adjusted to below 6.5. Then, the fourth inhibitor, the fourth rare earth collector, and the fourth frother are added in sequence to carry out secondary roughing to obtain secondary roughing concentrate and secondary roughing tailings. The secondary roughing concentrate is then subjected to primary cleaning to obtain rare earth concentrate and rare earth middlings. The rare earth middlings are returned to the secondary roughing.

[0063] In step 4, a vertical mill is used for grinding, and the grinding media are steel balls and ceramic grinding media with a mass ratio of 3:1. The fineness of the ground ore after grinding is -500 mesh, accounting for 70%. The mass concentration of the slurry after conditioning is 50%, the slurry temperature is 45℃, and the pH is 5.5. The fourth inhibitor includes nitric acid triacetic acid and fulvic acid with a mass ratio of 6:1. The dosage of the fourth inhibitor is 0.6 kg / t. The fourth rare earth collector is alkylamine dimethylphosphonic acid, with a dosage of 0.8 kg / t. The fourth frother is methyl isobutyl methanol, with a dosage of 60 g / t.

[0064] The steps for primary cleaning of the secondary roughing concentrate include: S401. The secondary roughing concentrate is added to the flotation cell, water is added to adjust the slurry, and the fifth depressant, the fifth rare earth collector, and the fifth frother are added sequentially for fine selection to obtain rare earth concentrate and rare earth middlings. The fifth depressant has the same composition as the fourth depressant, the fifth rare earth collector has the same composition as the fourth rare earth collector, and the fifth frother has the same composition as the fourth frother. The dosage of the fifth depressant is 0.3 kg / t, the dosage of the fifth rare earth collector is 0.4 kg / t, and the dosage of the fifth frother is 30 g / t.

[0065] like Figure 2 The XRD analysis results of the rare earth concentrate from Example 1 are shown. The rare earth grade of the final rare earth concentrate obtained in this example is 66.24%, the rare earth recovery rate is 60.89%, the CaO content is 4.83%, the SiO2 content is 0.57%, the F content is 3.56%, and the P content is 4.41%.

[0066] Example 2 This embodiment provides a mineral processing method for upgrading and reducing impurities in rare earth ore. The method in this embodiment is generally the same as that in Embodiment 1, except for some different process parameters, as detailed below: In step 1, the rare earth ore components, by mass percentage, mainly include: rare earth: 8.59%, CaO: 25.94%, SiO2: 16.43%, F: 12.76%, P: 1.55%. The mass concentration of the rare earth ore slurry is 55%, the pH is 9, and the amount of saline water glass used is 1.8 kg / t. The mass ratio of 1-alkoxy-2-naphthyl hydroxamic acid to oxidized paraffin soap is 8:1. The amount of the first rare earth collector used is 0.6 kg / t, and the amount of scavenging collector used is 0.3 kg / t. In step 2, the dosage of the second inhibitor is 0.9 kg / t, and the dosage of the second rare earth collector is 0.3 kg / t; In step 3, the dosage of the third inhibitor is 0.45 kg / t, and the dosage of the third rare earth collector is 0.15 kg / t; In step 4, the grinding fineness after grinding is -400 mesh, accounting for 80%; the mass concentration of the slurry after slurry conditioning is 45%, the slurry temperature is 40℃, and the pH is 6; the mass ratio of triacetic acid to fulvic acid is 8:1.5; the dosage of the fourth inhibitor is 0.4 kg / t, the dosage of the fourth rare earth collector is 0.6 kg / t, and the dosage of the fourth frother is 80 g / t. In S401, the dosage of the fifth inhibitor is 0.2 kg / t, the dosage of the fifth rare earth collector is 0.3 kg / t, and the dosage of the fifth foaming agent is 40 g / t.

[0067] In this embodiment, the rare earth concentrate obtained has a rare earth grade of 68.02%, a rare earth recovery rate of 61.44%, a CaO content of 3.95%, a SiO2 content of 0.43%, a F content of 3.19%, and a P content of 3.96%.

[0068] Example 3 This embodiment provides a mineral processing method for upgrading and reducing impurities in rare earth ore. The method in this embodiment is generally the same as that in Embodiment 1, except for some different process parameters, as detailed below: In step 1, the rare earth ore components, by mass percentage, mainly include: rare earth: 11.07%, CaO: 20.39%, SiO2: 13.17%, F: 13.08%, P: 1.21%, the mass concentration of the rare earth ore slurry is 65%, and the pH is 9.5; the mass ratio of 1-alkoxy-2-naphthyl hydroxamic acid to oxidized paraffin soap is 9:2; the dosage of the first rare earth collector is 1.2 kg / t, the dosage of the first frother is 160 g / t; the dosage of the scavenging collector is 0.6 kg / t, and the dosage of the scavenging frother is 80 g / t. In step 2, the dosage of the second rare earth collector is 0.6 kg / t, and the dosage of the second foaming agent is 80 g / t; In step 3, the dosage of the third rare earth collector is 0.3 kg / t, and the dosage of the third foaming agent is 40 g / t; In step 4, the mass ratio of steel balls to ceramic media balls is 4:1; the grinding fineness after grinding is -325 mesh, accounting for 80%; the mass concentration of the slurry after slurry conditioning is 40%, the slurry temperature is 38℃, and the pH is 6.2; the mass ratio of triacetic acid to fulvic acid is 9:2; the dosage of the fourth inhibitor is 0.8 kg / t, the dosage of the fourth rare earth collector is 0.65 kg / t, and the dosage of the fourth frother is 90 g / t. In S401, the dosage of the fifth inhibitor is 0.4 kg / t, the dosage of the fifth rare earth collector is 0.325 kg / t, and the dosage of the fifth foaming agent is 45 g / t.

[0069] In this embodiment, the rare earth concentrate obtained has a rare earth grade of 67.45%, a rare earth recovery rate of 62.18%, a CaO content of 3.98%, a SiO2 content of 0.49%, a F content of 3.44%, and a P content of 4.15%.

[0070] Extensive research was conducted during the study process, and some suboptimal solutions are presented here as comparative examples.

[0071] Comparative Example 1 This comparative example provides a method for beneficiating rare earth ore. The rare earth ore in this comparative example is the same as that in Example 1. The overall steps of the beneficiation method in this comparative example are the same as those in Example 1, except that: In steps 1 to 3, the first inhibitor, the second inhibitor, and the third inhibitor are all made of water glass; the first rare earth collector, the second rare earth collector, and the third rare earth collector are all made of 1-alkoxy-2-naphthohydroxyoxime acid.

[0072] The rare earth concentrate obtained in this comparative example has a rare earth grade of 58.33%, a rare earth recovery rate of 57.46%, and a SiO2 content of 1.19%. The rare earth grade and recovery rate of the method in this comparative example are much lower than those of Example 1, and the SiO2 content is high.

[0073] Comparative Example 2 This comparative example provides a method for beneficiating rare earth ore. The rare earth ore in this comparative example is the same as that in Example 1. The overall steps of the beneficiation method in this comparative example are the same as those in Example 1, except that: In step 4, both the fourth and fifth inhibitors use fulvic acid.

[0074] The rare earth concentrate obtained in this comparative example has a rare earth grade of 65.48%, a rare earth recovery rate of 60.25%, and a phosphorus content of 5.97%. The rare earth grade and recovery rate of the method in this comparative example are lower than those of Example 1, while the phosphorus content is higher.

[0075] Comparative Example 3 This comparative example provides a method for beneficiating rare earth ore. The rare earth ore in this comparative example is the same as that in Example 1. The overall steps of the beneficiation method in this comparative example are the same as those in Example 1, except that: In step 4, both the fourth and fifth inhibitors are aziridine triacetic acid.

[0076] The rare earth concentrate obtained in this comparative example has a rare earth grade of 64.18%, a rare earth recovery rate of 59.46%, and an F content of 5.53%. The rare earth grade and recovery rate of the method in this comparative example are lower than those of Example 1, while the F content is higher.

[0077] Comparative Example 4 This comparative example provides a method for beneficiating rare earth ore. The rare earth ore in this comparative example is the same as that in Example 1. The overall steps of the beneficiation method in this comparative example are the same as those in Example 1, except that: In step 4, the secondary concentrate is not ground and is directly subjected to secondary roughing.

[0078] The rare earth concentrate obtained in this comparative example has a rare earth grade of 60.82%, a rare earth recovery rate of 56.17%, a CaO content of 7.33%, a SiO2 content of 1.12%, a F content of 4.46%, and a P content of 4.58%. The rare earth grade and recovery rate of the method in this comparative example are lower than those of Example 1, and the contents of Ca, F, Si, and P impurities are high.

[0079] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A mineral processing method for upgrading and reducing impurities in rare earth ore, characterized in that, The mineral processing method includes the following steps: Step 1, Primary roughing: Adjust the pH of the rare earth ore slurry to above 7, and sequentially add the first inhibitor, the first rare earth collector, and the first frother for primary roughing to obtain rough concentrate and rough tailings; the rough concentrate is subsequently subjected to two cleaning processes, and the rough tailings are subjected to one scavenging process to obtain scavenged concentrate and scavenged tailings; the first inhibitor is saline water glass, and the first rare earth collector includes 1-alkoxy-2-naphthylhydroxyxamic acid and oxidized paraffin soap; Step 2, First Cleaning: Add the rougher concentrate to the flotation cell, add water to adjust the slurry, and then add the second inhibitor, the second rare earth collector, and the second frother in sequence to carry out the first cleaning, and obtain the first cleaned concentrate and the first cleaned middlings. Step 3, Second Cleaning: Add the primary cleaned concentrate to the flotation cell, add water to adjust the slurry, and then add the third inhibitor, the third rare earth collector and the third frother in sequence for the second cleaning to obtain the secondary cleaned concentrate and the secondary cleaned middlings. The second and third inhibitors have the same composition as the first inhibitor, and the second and third rare earth collectors have the same composition as the first rare earth collector. Step 4, Secondary roughing: After grinding the secondary refined concentrate, water is added to adjust the slurry to pH 4-6.

5. The fourth inhibitor, the fourth rare earth collector, and the fourth frother are added sequentially for secondary roughing to obtain secondary roughing concentrate and secondary roughing tailings. The secondary roughing concentrate is then subjected to primary refining to obtain rare earth concentrate and rare earth middlings. The rare earth middlings are returned to the secondary roughing. The fourth inhibitor includes nitric acid triacetic acid and fulvic acid.

2. The mineral processing method according to claim 1, characterized in that, In step 4, the fourth rare earth collector is alkylamine dimethylphosphonic acid, and the dosage of the fourth rare earth collector is 0.5-2.0 kg / t; the fourth foaming agent is methyl isobutyl methanol, and the dosage of the fourth foaming agent is 10-100 g / t.

3. The mineral processing method according to claim 1, characterized in that, In step 1, the mass ratio of 1-alkoxy-2-naphthylhydroxyoxime acid to oxidized paraffin soap in the first rare earth collector is 7-10:1-2.

4. The mineral processing method according to claim 1, characterized in that, In step 1, the mass concentration of the rare earth ore slurry is 45-70%, the pH is adjusted to 7-11, and the temperature of the slurry is 35-75℃.

5. The mineral processing method according to claim 1, characterized in that, In step 1, the amount of the first inhibitor added is 0.5 to 3.0 kg / t.

6. The mineral processing method according to claim 1, characterized in that, In step 1, the saline water glass is prepared by the following method: water glass is mixed with aluminum salt by stirring; wherein the aluminum salt is one or more of aluminum chloride and aluminum sulfate.

7. The mineral processing method according to claim 6, characterized in that, In step 1, the mass ratio of water glass to aluminum salt is 5:1 to 9:

1.

8. The mineral processing method according to claim 1, characterized in that, The first foaming agent is pine oil, and the amount added is 30-200g / t.

9. The mineral processing method according to claim 1, characterized in that, In step 4, during the secondary fine concentrate grinding process, steel balls and ceramic grinding media are used, with a mass ratio of 3 to 5:

1.

10. The mineral processing method according to any one of claims 1 to 9, characterized in that, In step 4, the mass ratio of nitric acid triacetic acid to fulvic acid in the fourth inhibitor is 5-9:0.5-2.

Images