Flotation purification process for neon-type low-grade rare earth ore

Abstract

The invention discloses a flotation purification process for neon-type low-grade rare earth ore. The flotation purification process comprises the steps that the neon-type low-grade rare earth ore is subjected to ball milling, crushing and screening, and ore is obtained; the ore is added into a flotation tank, deionized water is added to obtain ore pulp, a flotation machine is started, the temperature and pH of the ore pulp are adjusted, an inhibitor and a collecting agent are added, stirring is conducted, and rough concentrate is obtained; and the rough concentrate continues to be added into the flotation tank, deionized water is added to obtain ore pulp, a flotation machine is started, the temperature and pH of the ore pulp are adjusted, an inhibitor and a collecting agent are added, stirring is conducted, and rare earth concentrate is obtained. According to the method, flotation conditions are optimized, effective separation and enrichment of rare earth minerals are achieved, the recovery rate and grade of the rare earth minerals are remarkably improved and reach 86.66% and 15.06%, and the resource recovery efficiency is effectively improved. Compared with a traditional chemical leaching method, the flotation technology is adopted, chemical pollution to the environment is reduced, and the requirement for environmental protection is met.

Description

Technical Field

[0001] The invention relates to a flotation purification process for a neon-type low-grade rare earth ore, belonging to the technical field of ore dressing. Background Art

[0002] Nephrite-type low-grade rare earth ores usually have complex mineral compositions, with rare earth minerals coexisting with gangue minerals, and the ores contain a variety of complex minerals such as calcite, pyrite, mica, barite, etc., which makes it difficult to separate and extract rare earths. At present, the main beneficiation methods for low-grade rare earth ores include physical beneficiation, chemical leaching and solvent extraction. Physical beneficiation methods usually have a low recovery rate and are difficult to meet economic efficiency requirements; chemical leaching methods are difficult to treat acidic or alkaline waste liquids and may cause environmental pollution; solvent extraction methods have complex processes, strict conditions, are easily affected by operating errors, and are prone to secondary pollution to the environment.

[0003] In view of the comprehensive utilization of rare earth tailings, some studies have used flotation methods to recover rare earth minerals. For example, for the Bayan Obo tailings, Qin Yufang et al. (Overview of Research on Bayan Obo Tailings Reservoir and Its Resource Utilization [J], Comprehensive Utilization of Minerals, 2020, (06): 100-9) used flotation technology to recover rare earths and achieved good results. In addition, for the flotation purification process of low-grade rare earth ores, such as the patented frother for rare earth ore dressing and the room temperature dressing process for low-grade and difficult-to-select rare earth ores (CN103301949A), the flotation pre-enrichment-wet strong magnetic separation purification method was used to obtain high-grade and high-recovery rare earth concentrates. However, research on the flotation purification process for nepheline-type low-grade rare earth ores is still relatively limited, and it is urgent to develop new processes to improve the recovery rate and grade of rare earths.

[0004] In summary, the mineral paragenesis of nephrite-type rare earth ores is complex (monazite accounts for only 4.2%), and the recovery rate of traditional physical mineral processing is less than 50%; the chemical leaching method produces acidic / alkaline waste liquid (the treatment cost accounts for more than 30% of the operating cost); the solvent extraction method requires strict control of operating conditions (temperature error ±2°C will cause the recovery rate to drop by 15%); the existing flotation process has not solved the problem of entrainment of fine particles with a particle size greater than 200 mesh (the concentrate grade drops by 20-30%). Therefore, although the existing technology can process some simple rare earth ores to a certain extent, when faced with nephrite-type low-grade rare earth ores, the effect of the flotation purification process is often unsatisfactory. Due to the particularity of this type of ore, it is necessary to develop a more efficient, environmentally friendly flotation process that can greatly improve the recovery rate and grade. Summary of the invention

[0005] In view of the problems existing in the above-mentioned prior art, the present invention provides a flotation purification process for nepheline type low-grade rare earth ore, which improves the recovery rate and grade of nepheline type low-grade rare earth ore and reduces environmental pollution.

[0006] In order to achieve the above object, the present invention adopts a flotation purification process of nepheline type low-grade rare earth ore, comprising the following steps:

[0007] (1) ball milling, crushing, and screening the nepheline type low-grade rare earth ore to obtain ore with a particle size of 200 mesh to 325 mesh;

[0008] (2) Add the ore to the flotation tank, add deionized water to obtain a slurry concentration of 10%-30%, start the flotation machine, set the stirring speed to 1600-2000rpm, and the aeration volume to 0.05-0.2m 3 / h, adjust the slurry temperature to 20℃-30℃, pH to 7-11, add inhibitors and collectors, stir, and obtain a coarse concentrate;

[0009] (3) Continue to add the coarse concentrate to another flotation tank, add deionized water to obtain a slurry concentration of 10%-30%, start the flotation machine, set the stirring speed to 1600-2000rpm, and the inflation volume to 0.05-0.2m 3 / h, adjust the slurry temperature to 20°C-30°C, the pH to 7-11, add inhibitors and collectors, stir, and obtain rare earth concentrate.

[0010] As an improvement, the inhibitor in steps (2) and (3) is water glass, and the dosage is 1600-2700 g / t.

[0011] As an improvement, the amount of water glass used is 2400g / t.

[0012] As an improvement, the collector in steps (2) and (3) is salicylic hydroxamic acid, with the dosage being 600-1400 g / t.

[0013] As an improvement, the dosage of the salicylic hydroxamic acid is 1200 g / t.

[0014] As an improvement, a foaming agent is further added in steps (2) and (3), wherein the foaming agent is MIBC, and the dosage is 100-300 g / t.

[0015] As an improvement, a pH adjuster is added to steps (2) and (3) respectively, and the pH adjuster is at least one of NaOH and HCl.

[0016] As an improvement, the pH in steps (2) and (3) is 9.

[0017] As an improvement, in steps (2) and (3), the concentration of the slurry is 25% and the temperature is adjusted to 25°C.

[0018] As an improvement, the following steps are included:

[0019] (1) ball milling, crushing, and screening the nepheline type low-grade rare earth ore to obtain ore with a particle size of 200 mesh to 325 mesh;

[0020] (2) Add the ore to the flotation tank, add deionized water to obtain a slurry with a concentration of 25%, start the flotation machine, set the stirring speed to 1800 rpm, and the aeration volume to 0.1 m 3 / h, adjusting the slurry temperature to 25°C and the pH to 9, adding 2400g / t of water glass and 1200g / t of salicylic hydroxamic acid, stirring, and obtaining a coarse concentrate;

[0021] (3) Continue to add the coarse concentrate to another flotation tank, add deionized water to obtain a slurry concentration of 10%-30%, start the flotation machine, set the stirring speed to 1800rpm, and the aeration volume to 0.1m 3 / h, adjust the slurry temperature to 25°C and the pH to 9, add 2400g / t of water glass and 1200g / t of salicylic hydroxamic acid, stir and obtain rare earth concentrate.

[0022] Compared with the prior art, the flotation purification process of nepheline type low-grade rare earth ore of the present invention has the following beneficial effects:

[0023] 1) Improve recovery rate and grade: By optimizing the flotation process and the use of reagents, the recovery rate of rare earth ore can reach 86.66% and the grade is 15.06%, which are significantly higher than the recovery rate and grade of the traditional method.

[0024] 2) Environmentally friendly: The flotation method is used to replace the traditional chemical leaching and solvent extraction methods, which reduces the use of chemical agents and wastewater treatment problems, and has lower environmental pollution and better sustainability.

[0025] 3) Process simplification and cost reduction: The flotation process of the present invention is simple, the operation process is short, the equipment requirements are low, the production cost is relatively low, it is suitable for large-scale production, and has broad industrial application prospects.

[0026] 4) Improved the selectivity of flotation agents: By optimizing the use of flotation agents (salicylic hydroxamic acid, sodium silicate solution, etc.), the flotation selectivity of rare earth minerals was successfully improved, the flotation of associated minerals was reduced, and the resource utilization efficiency was improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 The flotation process flow chart of the nepheline type low-grade rare earth ore of the present invention;

[0029] Figure 2 It is a schematic diagram of the grade and recovery rate of rare earth flotation concentrate under different particle size conditions;

[0030] Figure 3 It is a schematic diagram of the grade and recovery rate of rare earth flotation concentrate at different pulp concentrations;

[0031] Figure 4 It is a schematic diagram of the grade and recovery rate of rare earth flotation concentrate under different pH conditions;

[0032] Figure 5 This is a schematic diagram of the grade and recovery rate of rare earth flotation concentrate under different water glass dosage conditions;

[0033] Figure 6 This is a schematic diagram of the grade and recovery rate of rare earth flotation concentrate under different salicylic acid dosage conditions. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clear, the technical solutions of the present application are described in detail below with the help of accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations on the technical solutions of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0035] The unit involved in the following examples is g / t, where t represents the mass of the original ore, that is, the added mass of the reagent relative to the original ore.

[0036] Example 1

[0037] The influence of flotation particle size on the flotation effect of nepheline type low-grade rare earth ore:

[0038] (1) A low-grade rare earth ore of the neon type in Inner Mongolia was ground into different particle sizes after reduction, mixing, crushing and grinding, specifically: less than 200 mesh, 200 mesh-325 mesh, 325 mesh-400 mesh, and greater than 400 mesh;

[0039] (2) The composition of rare earth minerals was analyzed by X-ray fluorescence spectrometer (XRF) to provide the content data of each element in the ore sample; the mineral composition of the ore was analyzed by X-ray diffractometer (XRD) to determine the types and contents of rare earth minerals and gangue minerals in the ore, as shown in Table 1 below;

[0040] Table 1 Ore mineral composition and content (%)

[0041]

[0042] According to X-ray fluorescence spectrum (XRF) and X-ray diffraction (XRD) analysis, the main components of the ore are aegirine, calcite, pyrite, mica, barite, monazite, etc.

[0043] (3) Drug configuration:

[0044] The inhibitor is water glass (sodium silicate solution, modulus 2.4), with a dosage of 1600g / t, which is used to inhibit the flotation of gangue minerals (such as calcite and mica) and increase the flotation selectivity of rare earth minerals;

[0045] The collector is salicylic hydroxamic acid, with a usage of 1000g / t, to improve the flotation efficiency of rare earth minerals;

[0046] The foaming agent is MIBC, with a dosage of 200g / t;

[0047] The pH adjuster uses sodium hydroxide (NaOH) or hydrochloric acid (HCl) to adjust the pH value of the slurry;

[0048] (4) Figure 1 As shown in the figure, 500g of the treated ore sample is taken and added to the flotation tank, deionized water is added to adjust the pulp concentration to 20%, the pulp temperature is adjusted to 25℃, the natural pH, water glass, collector salicylic hydroxamic acid and frother MIBC are added; at the same time, the XFG-500 hanging trough flotation machine produced by Wuhan Prospecting Machinery Co., Ltd. is used. This equipment is suitable for stirring the pulp, uniformly dispersing the reagents and combining bubbles with minerals. The stirring speed is set to 1800rpm and the aeration volume is set to 0.1m 3 / h, ensuring good contact between minerals and bubbles; after 6 minutes of reaction, rare earth minerals adhere to the bubbles and float up to form a foam layer, which is scraped off to obtain a coarse concentrate, and the rest is tailings;

[0049] Using the coarse concentrate as the raw material, following the same operation steps as above, deionized water is added again to obtain a slurry with a concentration of 20%, and inhibitors, collectors and frothers are added to further inhibit the flotation of impurity minerals, promote the combination of rare earth minerals and bubbles, and through the stirring and aeration of the flotation machine, the rare earth minerals are more fully enriched. The product obtained after flotation is the selected rare earth concentrate, which realizes the efficient separation and enrichment of rare earth minerals;

[0050] (5) After flotation, the concentrate and tailings are collected separately, filtered, dried and weighed;

[0051] Analytical testing: XRF is used to analyze the composition of concentrates and tailings to determine the recovery rate and grade of rare earths.

[0052] Calculate flotation recovery and rare earth grade. The recovery formula is:

[0053]

[0054]

[0055] The results are as follows Figure 2 And as shown in Table 2.

[0056] Table 2 Grade and recovery of rare earth flotation concentrate under different particle size conditions

[0057] Particle size conditions Yield (%) Rare earth grade (%) Rare earth recovery rate (%) More than 200 mesh 47.32 6.34 35.46 More than 200 and less than 325 mesh 66.77 10.98 86.66 More than 325 and less than 400 mesh 69.25 9.67 79.15 More than 400 mesh 62.04 8.22 60.28

[0058] Example 2

[0059] Effect of slurry concentration on flotation effect of nepheline type low-grade rare earth ore:

[0060] (1) A low-grade rare earth ore of the neon type in Inner Mongolia. After pretreatment, the ore particle size is 200-325 mesh;

[0061] (2) Drug configuration:

[0062] The inhibitor is water glass (sodium silicate solution), with a dosage of 1600g / t;

[0063] The collector used was salicylic hydroxamic acid, with a usage of 1000 g / t; the temperature was adjusted to 25°C;

[0064] The foaming agent is MIBC, the dosage is 200g / t; natural pH value;

[0065] (3) Take 500 g of the processed ore sample and set the slurry concentration: add deionized water to adjust the slurry concentration to 10%, 15%, 20%, 25%, and 30% respectively;

[0066] (4) Add the slurry to the flotation tank and add the adjusted flotation reagent to ensure that the reagent is evenly distributed. Set the stirring speed to 1800 rpm and the aeration volume to 0.1 m 3 / h;

[0067] (5) After flotation, the concentrate and tailings are collected separately, filtered, dried and weighed.

[0068] The results are as follows Figure 3 And as shown in Table 3.

[0069] Table 3 Grade and recovery of rare earth flotation concentrate at different pulp concentrations

[0070] Slurry concentration / % Yield (%) Rare earth grade (%) Rare earth recovery rate (%) 10 52.42 9.17 56.82 15 58.08 9.87 67.76 20 66.77 10.98 86.66 25 63.61 11.55 86.84 30 64.13 10.96 83.08

[0071] Example 3

[0072] Effect of pH value on flotation of low-grade rare earth ores of nepheline type:

[0073] (1) Take the same nepheline-type low-grade rare earth ore from Inner Mongolia, and after pretreatment, the ore particle size is 200-325 mesh;

[0074] (2) Drug configuration:

[0075] The inhibitor is water glass (sodium silicate solution), with a dosage of 1600g / t;

[0076] The collector is salicylic hydroxamic acid, and the usage is 1000g / t;

[0077] The foaming agent is MIBC, with a dosage of 200g / t;

[0078] (3) pH adjuster uses sodium hydroxide (NaOH) or hydrochloric acid (HCl) to set the pH value of the slurry to 7, 8, 9, 10, and 11 respectively;

[0079] (4) Take 500 g of the treated ore sample and add it to the flotation tank. Add deionized water to adjust the pulp concentration to 25%. Add water glass, collector salicylic hydroxamic acid and frother MIBC. Set the stirring speed to 1800 rpm and the aeration volume to 0.1 m 3 / h, the temperature is adjusted to 25℃;

[0080] (5) After flotation, the concentrate and tailings are collected separately, filtered, dried and weighed.

[0081] The results are as follows Figure 4 And as shown in Table 4.

[0082] Table 4 Grade and recovery of rare earth flotation concentrate under different pH conditions

[0083] pH Yield (%) Rare earth grade (%) Rare earth recovery rate (%) 7 52.47 10.31 63.94 8 45.43 12.95 69.54 9 45.30 15.06 80.64 10 47.12 14.63 81.49 11 36.82 11.87 51.66

[0084] Example 4

[0085] The influence of the change of flotation reagent dosage on the flotation effect:

[0086] (1) The same nepheline-type low-grade rare earth ore in Inner Mongolia has a particle size of 200-325 mesh after pretreatment;

[0087] (2) Water glass (inhibitor): 1600 g / t, 1900 g / t, 2100 g / t, 2400 g / t, 2700 g / t;

[0088] Salicylic acid (collector): 600g / t, 800g / t, 1000g / t, 1200g / t, 1400g / t; flotation experiments were conducted according to the above reagents with different concentrations, and the recovery rate and grade of each group of experiments were recorded. When conducting the inhibitor dosage test, the dosage of salicylic acid was fixed at 1000g / t;

[0089] The foaming agent is MIBC, with a dosage of 200g / t;

[0090] (3) Slurry concentration 25%, pH 9, particle size 200-325 mesh, temperature 25°C, stirring speed 1800 rpm, and aeration volume set to 0.1 m 3 / h, flotation time 6min;

[0091] (4) After flotation, the concentrate and tailings are collected separately, filtered, dried and weighed.

[0092] The results are as follows Figure 5 , Figure 6 As shown in Table 5 and Table 6.

[0093] Table 5 Water glass dosage test results

[0094] Water glass dosage / (g / t) Yield (%) Rare earth grade (%) Rare earth recovery rate (%) 1600 45.30 15.06 80.64 1900 38.70 17.41 79.64 2100 32.45 20.22 77.56 2400 29.46 23.47 81.73 2700 24.79 24.42 71.56

[0095] Table 6 Salicylic hydroxamic acid dosage test results

[0096] Salicylic hydroxamic acid dosage / (g / t) Yield (%) Rare earth grade (%) Rare earth recovery rate (%) 600 29.82 19.29 67.99 800 28.76 22.69 77.14 1000 29.46 23.47 81.73 1200 28.04 25.05 83.03 1400 29.63 23.96 83.92

[0097] The present invention proposes optimized flotation conditions for the flotation purification process of nepheline-type low-grade rare earth ores, including particle size, pulp concentration, pH value, dosage of inhibitors and collectors, etc. In view of the complex composition and multiple associated minerals of nepheline-type low-grade rare earth ores, the present invention realizes effective separation and enrichment of rare earth minerals by optimizing flotation conditions.

[0098] Through experimental research, it was determined that the amount of water glass was 2400 / t, the amount of collector salicylic hydroxamic acid was 1200kg / t, the amount of MIBC was 200g / t, the pulp concentration was 25%, and the pH value was 9, which significantly improved the recovery rate and grade of rare earth ore to 86.66% and 15.06%, effectively improving the resource recovery efficiency. Compared with the traditional chemical leaching method, the present invention adopts flotation technology, reduces chemical pollution to the environment, and meets the requirements of green environmental protection.

[0099] The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims

1. A flotation purification process for nepheline-type low-grade rare earth ore, characterized in that: The following steps are involved: (1) ball milling, crushing, and screening the nepheline type low-grade rare earth ore to obtain ore with a particle size of 200 mesh to 325 mesh; (2) Add the ore to the flotation tank, add deionized water to obtain a slurry concentration of 10%-30%, start the flotation machine, set the stirring speed to 1600-2000rpm, and the aeration volume to 0.05-0.2m 3 / h, adjust the slurry temperature to 20℃-30℃, pH to 7-11, add inhibitors and collectors, stir, and obtain a coarse concentrate; (3) Continue to add the coarse concentrate to another flotation tank, add deionized water to obtain a slurry concentration of 10%-30%, start the flotation machine, set the stirring speed to 1600-2000rpm, and the inflation volume to 0.05-0.2m 3 / h, adjust the slurry temperature to 20°C-30°C, the pH to 7-11, add inhibitors and collectors, stir, and obtain rare earth concentrate.

2. The flotation purification process of a neon-type low-grade rare earth ore according to claim 1, characterized in that: The inhibitor in steps (2) and (3) is water glass, and the dosage is 1600-2700 g / t.

3. The flotation purification process of a neon-type low-grade rare earth ore according to claim 2, characterized in that: The dosage of the water glass is 2400g / t.

4. The flotation purification process of a nepheline type low-grade rare earth ore according to claim 1, characterized in that: The collector in steps (2) and (3) is salicylic hydroxamic acid, and the dosage is 600-1400 g / t.

5. The flotation purification process of a nepheline type low-grade rare earth ore according to claim 4, characterized in that: The dosage of the salicylic hydroxamic acid is 1200 g / t.

6. The flotation purification process of a nepheline type low-grade rare earth ore according to claim 1, characterized in that: In the steps (2) and (3), a foaming agent is further added. The foaming agent is MIBC, and the amount used is 100-300 g / t.

7. The flotation purification process of a nepheline type low-grade rare earth ore according to claim 1, characterized in that: A pH adjuster is added in steps (2) and (3) respectively, and the pH adjuster is at least one of NaOH and HCl.

8. The flotation purification process of a nepheline type low-grade rare earth ore according to claim 1, characterized in that: The pH in steps (2) and (3) is 9.

9. The flotation purification process of a nepheline type low-grade rare earth ore according to claim 1, characterized in that: In the steps (2) and (3), the concentration of the slurry is 25%, and the temperature is adjusted to 25°C.

10. The flotation purification process of a nepheline type low-grade rare earth ore according to claim 1, characterized in that: The following steps are involved: (1) ball milling, crushing, and screening the nepheline type low-grade rare earth ore to obtain ore with a particle size of 200 mesh to 325 mesh; (2) Add the ore to the flotation tank, add deionized water to obtain a slurry with a concentration of 25%, start the flotation machine, set the stirring speed to 1800 rpm, and the aeration volume to 0.1 m 3 / h, adjusting the slurry temperature to 25°C and the pH to 9, adding 2400g / t of water glass and 1200g / t of salicylic hydroxamic acid, stirring, and obtaining a coarse concentrate; (3) Continue to add the coarse concentrate to another flotation tank, add deionized water to obtain a slurry concentration of 10%-30%, start the flotation machine, set the stirring speed to 1800rpm, and the aeration volume to 0.1m 3 / h, adjust the slurry temperature to 25°C and the pH to 9, add 2400g / t of water glass and 1200g / t of salicylic hydroxamic acid, stir and obtain rare earth concentrate.

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