Method for recovering iron from iron tailings and use thereof

Abstract

The application discloses a recovery method and application of iron tailings, and belongs to the field of mineral processing technology.The recovery method comprises the following steps: 1) slurry preparation of the iron tailings to obtain a slurry; adding water glass and sodium oleate related substances into the slurry in sequence, and then performing flotation to obtain a mixed flotation froth product and a mixed flotation sand; 2) filtering the mixed flotation froth product to obtain a solid; drying the solid, and then performing roasting at 400-650 DEG C to obtain a roasting product; performing grinding of the roasting product to obtain a grinding product; 3) slurry preparation of the grinding product to obtain a grinding product slurry; adding sodium sulfide, water glass, sodium alginate, hydroxamic acid and pine oil into the grinding product slurry in sequence, and then performing flotation to obtain a rare earth concentrate and a rare earth tailings.The rare earth concentrate obtained by the application has a high grade, and the phosphorus content and the sulfur content in the rare earth concentrate can be reduced simultaneously.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for recovering selected iron tailings and its use, in particular to a method for recovering rare earth concentrate and fluorite concentrate from selected iron tailings and the use of sodium sulfide. BACKGROUND

[0002] At present, the selected iron tailings preferentially float rare earths to obtain a mixed rare earth concentrate with a REO content of 56-58wt% and a REO recovery rate of 40-50%. Then, the rare earth tailings are re-flotation fluorite to obtain a fluorite concentrate with a CaF2 content of 85-90wt% and a CaF2 recovery rate of 30-40%.

[0003] Because rare earth minerals coexist with gangue minerals such as fluorite, and have similar floatability, the depressant lacks selective action, the separation effect of flotation is poor, the content of impurity elements in rare earth concentrate is high, which leads to a large amount of slag in the subsequent smelting process of rare earth concentrate. In addition, due to the close symbiotic relationship between rare earth and fluorite minerals, the rare earth mineral monomer in the selected iron tailings has low dissociation degree, the grade of rare earth concentrate still needs to be improved, and the phosphorus content and sulfur content in rare earth concentrate still needs to be reduced.

[0004] CN108580023A discloses a beneficiation method for multi-component recovery from iron tailings associated with rare earth minerals, comprising: carrying out mixed flotation of rare earth minerals and fluorite minerals from iron tailings associated with rare earth minerals to obtain mixed flotation concentrate and mixed flotation tailings; carrying out strong magnetic separation on the mixed flotation concentrate to obtain strong magnetic separation concentrate and strong magnetic separation tailings; carrying out rare earth flotation on the strong magnetic separation concentrate to obtain rare earth flotation concentrate and rare earth flotation tailings; and carrying out fluorite flotation on the strong magnetic separation tailings to obtain fluorite flotation concentrate and fluorite flotation tailings. The patent document does not involve the phosphorus content and sulfur content in rare earth concentrate.

[0005] CN112791847A discloses a method for separating and recovering iron, rare earth and fluorine from iron tailings containing rare earth, which mixes, briquettes or spheroids the iron tailings containing rare earth, additives and coal powder, roasts, ball grinds and magnetically separates to obtain magnetic separation iron concentrate and magnetic separation tailings; adds hydrochloric acid to the magnetic separation tailings for leaching, filters to obtain rare earth chloride leaching solution and fluorite-rich leaching residue; adds water glass, sodium oleate and pine oil to the leaching residue to obtain rough separation concentrate and rough separation tailings, and obtains fluorite concentrate and total tailings containing silicates and a small amount of fluorite after fine separation. SUMMARY

[0006] One object of the present application is to provide a method for recovering a tailing of iron ore dressing. The method for recovering a tailing of iron ore dressing according to the present application can significantly reduce the content of phosphorus (in terms of P2O5) and sulfur in the obtained rare earth concentrate. Further, the present application can obtain a rare earth concentrate and a fluorite concentrate, respectively. Another object of the present application is to provide a use of sodium sulfide in treating a tailing of iron ore dressing to improve the grade of the obtained rare earth concentrate and reduce the content of P2O5 and S in the obtained rare earth concentrate.

[0007] The object of the present application is achieved by the following technical solutions.

[0008] The present application provides a method for recovering a tailing of iron ore dressing, comprising the following steps:

[0009] 1) Slurry the tailing of iron ore dressing to obtain a slurry; add water glass and related substances of sodium oleate into the slurry in sequence, and obtain a mixed flotation froth product and a mixed flotation sand through flotation;

[0010] 2) Filter the mixed flotation froth product to obtain a solid, dry the solid, and roast the solid at 400-650 ℃ to obtain a roasted product; grind the roasted product to obtain a ground product;

[0011] 3) Slurry the ground product to obtain a ground product slurry; add sodium sulfide, water glass, sodium alginate, hydroxamic acid and pine oil into the ground product slurry in sequence, and obtain a rare earth concentrate and a rare earth tailing through flotation;

[0012] wherein,

[0013] In step 1), the amount of water glass added is 0.1-6.0 kg / t based on the weight of the tailing of iron ore dressing; the amount of related substances of sodium oleate added is 0.1-1.0 kg / t;

[0014] In step 3), the amount of sodium sulfide added is 0.1-2.0 kg / t, the amount of water glass added is 0.1-6.0 kg / t, the amount of sodium alginate added is 0.01-0.3 kg / t, the amount of hydroxamic acid added is 0.1-1.5 kg / t, and the amount of pine oil added is 0.03-0.20 kg / t, all based on the weight of the tailing of iron ore dressing; the hydroxamic acid is selected from at least one of salicylhydroxamic acid and o-hydroxynaphthaldehyde hydroxamic acid;

[0015] The related substances of sodium oleate are selected from sodium oleate or a modified product of sodium oleate.

[0016] According to the method for recovering a tailing of iron ore dressing, preferably, in the tailing of iron ore dressing, the content of TFe is 10-15 wt%, the content of REO is 7-10 wt%, the content of CaF2 is 20-25 wt%, the content of P2O5 is 2.5-6.5 wt%, and the content of S is 1.5-3.0 wt%.

[0017] According to the recovery method, preferably, in step 1), the concentration of the ore slurry is 30-45 wt%; in the flotation, the pH value of the ore slurry is adjusted to 8-9.5; and the flotation temperature is 20-35℃.

[0018] According to the recovery method, preferably, in step 2), the roasting time is 1-5 h; and the particle size of the ground product is controlled to have a mass percentage of-38 μm of 80-90 wt%.

[0019] According to the recovery method, preferably, in step 3), the concentration of the ground product ore slurry is 50-70 wt%; in the flotation, the pH value of the ground product ore slurry is adjusted to 8-9; and the flotation temperature is 50-90℃.

[0020] According to the recovery method, preferably, the method further comprises the following steps:

[0021] 4) slurrying the rare earth tailings to obtain a rare earth tailings slurry; adding water glass, a polyphenol derivative and a related substance of sodium oleate into the rare earth tailings slurry in sequence, and performing flotation of once roughing and multiple cleaning to obtain a fluorite concentrate and a fluorite tailings;

[0022] wherein, based on the weight of the iron ore tailings, the water glass is added in an amount of 0.1-6.0 kg / t, the polyphenol derivative is added in an amount of 0.05-1.0 kg / t, and the related substance of sodium oleate is added in an amount of 0.1-1.0 kg / t.

[0023] According to the recovery method, preferably, in step 4), the concentration of the rare earth tailings slurry is 30-45 wt%; in the flotation, the pH value of the rare earth tailings slurry is adjusted to 8-9.5; and the flotation temperature is 20-40℃.

[0024] According to the recovery method, preferably, in steps 1) and 4), the related substance of sodium oleate is sodium oleate; and the polyphenol derivative is selected from at least one of tannin, tannin extract, and gallic acid.

[0025] According to the recovery method, preferably, the method further comprises the following step: combining the fluorite tailings with the mixed flotation sand to obtain a final tailings.

[0026] In another aspect, the application also provides a use of sodium sulfide in treating iron ore tailings to improve the grade of the obtained rare earth concentrate and reduce the P2O5 content and the S content in the obtained rare earth concentrate.

[0027] The method of the present application can improve the grade of the obtained rare earth concentrate while reducing the P2O5 content and S content in the obtained rare earth concentrate. Furthermore, the grade of the obtained fluorite concentrate is also high. Further, the recovery method of roasting-grinding the mixed flotation froth and adding specific flotation aids can promote the improvement of the grade of the rare earth concentrate and the fluorite concentrate, realize the effective separation of rare earth, fluorite and other gangue minerals, and reduce the P2O5 content and S content in the obtained rare earth concentrate. DETAILED DESCRIPTION

[0028] The present application will be further described below in conjunction with specific examples, but the scope of protection of the present application is not limited thereto.

[0029] As known by those skilled in the art, the subsequent treatment of rare earth concentrate generally adopts acid roasting process. If the sulfur content in the rare earth concentrate is high, the roasting will produce a ring phenomenon, and if the phosphorus content is high, the amount of added iron powder will be consumed. The rare earth concentrate has a requirement for the iron-phosphorus ratio during roasting, and the high phosphorus content requires more iron powder. Therefore, in the process of treating the iron tailings to obtain the rare earth concentrate and the fluorite concentrate, the present application particularly controls the phosphorus content and the sulfur content, so as to obtain a rare earth concentrate with high grade while reducing the phosphorus content and the sulfur content in the obtained rare earth concentrate. In addition, the recovery method of the present application can also obtain a fluorite concentrate with high CaF2 grade.

[0030] The recovery method of the iron tailings of the present application includes: 1) a flotation step of the iron tailings; 2) a roasting and grinding step; 3) a step of obtaining a rare earth concentrate. Optionally, it also includes: 4) a step of obtaining a fluorite concentrate, and 5) a step of obtaining a final tailings. The following will be described in detail.

[0031] <Flotation step of iron tailings>

[0032] The iron tailings are slurried to obtain a slurry; relevant substances of sodium silicate and sodium oleate are sequentially added to the slurry, and after flotation, a mixed flotation froth product and a mixed flotation sand are obtained.

[0033] In the iron separation tailings of the present application, the TFe content can be 10-15wt%, preferably 11-15wt%, more preferably 12-14wt%; the REO content can be 7-10wt%, preferably 8-10wt%, more preferably 9-9.5wt%; the CaF2 content is 20-25wt%, preferably 20-23wt%, more preferably 20-21wt%; the P2O5 content is 2.0-6.5wt%, preferably 2.35-5.84wt%, more preferably 2.5-5.0wt%, and the S content is 1.5-3.0wt%, preferably 1.80-2.5wt%, more preferably 1.88-1.94wt%. The recovery method of the present application is suitable for such iron separation tailings. In this way, the P2O5 content and S content of the obtained rare earth concentrate can be reduced while improving the grade of the obtained rare earth concentrate. In addition, a fluorite concentrate with a higher grade can also be recovered. In the present application, the phosphorus content is calculated as P2O5 content.

[0034] The concentration of the ore slurry can be 30-45wt%, preferably 32-40wt%, more preferably 35-38wt%. The amount of water glass added is 0.1-6.0kg / t, preferably 0.8-4.0kg / t, more preferably 1.5-2.5kg / t, based on the weight of the iron separation tailings. The amount of sodium oleate and related substances added can be 0.1-1.0kg / t, preferably 0.3-0.9kg / t, more preferably 0.5-0.7kg / t, based on the weight of the iron separation tailings.

[0035] In the present application, the sodium oleate and related substances are selected from sodium oleate or sodium oleate modified products, preferably sodium oleate. The source of sodium oleate is not particularly limited. Sodium oleate modified products can be purchased from Inner Mongolia Xinpao High-tech Development Co., Ltd., model SF, or from Baotou Mong Rong Fine Materials Co., Ltd., model 506F.

[0036] During flotation, the pH value of the ore slurry is adjusted to 8-9.5, preferably 8.5-9.5. The flotation temperature can be 20-35℃, preferably 25-35℃, more preferably 30-35℃.

[0037] In this step, the flotation is one roughing and multiple cleaning, preferably one roughing and two cleaning, i.e. one roughing and two cleaning flotation. The one roughing and two cleaning flotation refers to first performing one roughing, and then performing two cleanings. The flotation agents used in one roughing and two cleaning are the same, and the flotation conditions are the same. The middlings in one roughing and two cleaning flotation are returned in order to improve the recovery rate and reduce the loss.

[0038] <roasting and grinding step>

[0039] The mixed flotation froth product is filtered to obtain a solid; the solid is dried and roasted to obtain a roasted product; and the roasted product is ground to obtain a ground product. This is conducive to obtaining a rare earth concentrate with a high rare earth grade, and simultaneously reducing the P2O5 content and S content of the obtained rare earth concentrate.

[0040] The roasting temperature can be 400-650°C, preferably 450-620°C, more preferably 500-610°C, for example 520°C, 550°C, 580°C, or 600°C. The roasting time can be 1-5h, preferably 2-5h, more preferably 3-4h.

[0041] The particle size of the ground product is controlled to be 80-90wt%, preferably 85-90wt% of the mass percentage of -38μm. The grinding equipment can be a stirred mill, the filling medium is ceramic spherical particles, and the filling rate can be 35-45%, preferably 40-45%.

[0042] <Obtaining steps of the rare earth concentrate>

[0043] The ground product is slurried to obtain a ground product slurry; sodium sulfide, water glass, sodium alginate, hydroxamic acid, and pine oil are sequentially added to the ground product slurry, and one roughing and two cleaning flotation are performed to obtain a rare earth concentrate and a rare earth tailings. The addition of such specific flotation aids is conducive to improving the rare earth grade of the obtained rare earth concentrate, and reducing the P2O5 content and S content of the obtained rare earth concentrate. The present application surprisingly found that the addition of sodium sulfide in combination with other specific aids is conducive to achieving the purpose of the present application.

[0044] The concentration of the ground product slurry is 50-70wt%, preferably 55-70wt%, more preferably 60-65wt%.

[0045] The addition amount of sodium sulfide can be 0.1-2.0kg / t, preferably 0.4-1.5kg / t, more preferably 0.5-1.1kg / t, based on the weight of the iron ore tailings.

[0046] The addition amount of water glass is 0.1-6.0kg / t, preferably 0.9-5.0kg / t, more preferably 1.8-3.0kg / t, for example 1.0kg / t, 2.0kg / t, or 2.5kg / t, based on the weight of the iron ore tailings.

[0047] The addition amount of sodium alginate can be 0.01-0.3kg / t, preferably 0.1-0.3kg / t, more preferably 0.15-0.25kg / t, based on the weight of the iron ore tailings.

[0048] The amount of hydroxamic acid added can be 0.1-1.5 kg / t, preferably 0.5-1.3 kg / t, more preferably 0.8-1.1 kg / t, based on the weight of the iron ore tailings. The hydroxamic acid is selected from at least one of salicylhydroxamic acid and o-hydroxynaphthylhydroxamic acid, preferably o-hydroxynaphthylhydroxamic acid.

[0049] The amount of pinol oil added can be 0.03-0.20 kg / t, preferably 0.1-0.20 kg / t, more preferably 0.13-0.16 kg / t, based on the weight of the iron ore tailings.

[0050] During the flotation, the pH of the ground product slurry is adjusted to 8-9. The flotation temperature can be 50-90°C, preferably 60-85°C, more preferably 70-80°C.

[0051] In this step, the flotation is one roughing and multiple cleaning, preferably one roughing and two cleaning, i.e. one roughing and two cleaning flotation. One roughing and two cleaning flotation refers to first performing one roughing, and then performing two cleanings. The middlings of one roughing and two cleaning flotation are returned in order to improve the recovery rate and reduce the loss.

[0052] The obtained rare earth concentrate has a REO content of greater than 60 wt%, a CaF2 content of less than 5.0 wt%, a P2O5 content of less than 6.5 wt%, and a S content of less than 0.2 wt%.

[0053] <Obtaining step of fluorite concentrate>

[0054] The rare earth tailings are slurried to obtain a rare earth tailings slurry. The relevant substances of water glass, polyphenol derivative, and sodium oleate are sequentially added to the rare earth tailings slurry. The rare earth tailings slurry is subjected to flotation of one roughing and multiple cleanings to obtain a fluorite concentrate and a fluorite tailings. In this way, a fluorite concentrate with a higher CaF2 grade can be obtained, and the recovery rate can be improved.

[0055] The concentration of the rare earth tailings slurry can be 30-45 wt%, preferably 35-45 wt%, more preferably 35-40 wt%.

[0056] The amount of water glass added can be 0.1-6.0 kg / t, preferably 0.3-4.0 kg / t, more preferably 0.5-2.5 kg / t, based on the weight of the iron ore tailings.

[0057] The amount of polyphenol derivative added can be 0.05-1.0 kg / t, preferably 0.1-2.0 kg / t, more preferably 0.15-1.0 kg / t, such as 0.15 kg / t, 0.2 kg / t, 0.25 kg / t, based on the weight of the iron ore tailings. The polyphenol derivative is selected from at least one of tannin, tannin extract, and gallic acid, preferably tannin or gallic acid.

[0058] Based on the weight of iron tailings, the amount of sodium oleate and related substances added can be 0.1–1.0 kg / t, preferably 0.3–0.8 kg / t, and more preferably 0.4–0.6 kg / t. The related substances for sodium oleate are selected from sodium oleate or modified sodium oleate products, preferably sodium oleate. Modified sodium oleate products can be purchased from Inner Mongolia Xinbao High-Tech Development Co., Ltd. (model SF) or from Baotou Mengrong Fine Materials Co., Ltd. (model 506F).

[0059] During flotation, the pH of the rare earth tailings slurry is adjusted to 8–9.5, preferably 8.5–9.5. The flotation temperature can be 20–40℃, preferably 25–40℃, and more preferably 30–40℃.

[0060] A preferred flotation process is one roughing and multiple cleaning stages, typically involving one roughing and four or more cleaning stages, such as one roughing and eight cleaning stages (one rougher, eight cleaner flotation). This process involves first performing one roughing stage, followed by eight cleaning stages. The middlings are then combined and returned to the roughing stage in a closed-loop process to improve CaF2 recovery and reduce losses.

[0061] <Steps to obtain the final tailings>

[0062] The fluorite tailings are combined with the mixed flotation sediment to obtain the final tailings.

[0063] This invention also provides the use of sodium sulfide in treating iron ore tailings to improve the grade of the obtained rare earth concentrate and reduce the P2O5 and S content in the obtained rare earth concentrate, comprising the following steps:

[0064] 1) Adjust the iron tailings to obtain a slurry; add water glass and sodium oleate to the slurry in sequence, and then perform flotation to obtain a mixed flotation froth product and mixed flotation sand.

[0065] 2) The mixed flotation foam product is filtered and dried, and then roasted at 400-650°C to obtain a roasted product; the roasted product is then ground to obtain a ground product.

[0066] 3) Adjust the grinding product into a slurry to obtain the grinding product slurry; add sodium sulfide, water glass, sodium alginate, hydroxamic acid and pine oil to the grinding product slurry in sequence, and obtain rare earth concentrate and rare earth tailings by flotation.

[0067] in,

[0068] In step 1), the amount of water glass added is 0.1 to 6.0 kg / t based on the weight of the iron tailings; the amount of sodium oleate and related substances added is 0.1 to 1.0 kg / t.

[0069] In step 3), the adding amount of sodium sulfide is 0.1-2.0 kg / t based on the weight of the iron tailings, the adding amount of water glass is 0.1-6.0 kg / t, the adding amount of sodium alginate is 0.01-0.3 kg / t, the adding amount of hydroxamic acid is 0.1-1.5 kg / t, and the adding amount of pine oil is 0.03-0.20 kg / t; the hydroxamic acid is at least one selected from salicylhydroxamic acid and o-hydroxynaphthaldehyde hydroxamic acid;

[0070] The related substances of the sodium oleate are selected from sodium oleate or modified products of sodium oleate.

[0071] The detailed description is referred to the foregoing and will not be repeated here.

[0072] The test method is introduced as follows:

[0073] REO content: tested according to the method described in national standard GB / T 18114.1-2010.

[0074] CaF2 content: tested according to the method described in national standard GB / T 5195.1-2017.

[0075] TFe content: tested according to the method described in national standard GB / T 6730.5-2022.

[0076] P2O5 content: tested according to the method described in national standard GB / T 18114.9-2010.

[0077] S content: tested according to the method described in national standard GB / T 6730.61-2022.

[0078] Example 1

[0079] The iron tailings of Baotou Steel Baiyun Concentration Branch Company are used as raw materials, with TFe content of 11.96wt%, REO content of 9.57wt%, CaF2 content of 20.15wt%, P2O5 content of 3.45wt%, and S content of 1.9wt%.

[0080] The iron tailings are slurried to obtain a slurry with a concentration of 35wt%. At 30℃, 2.0 kg / t of water glass and 0.5 kg / t of sodium oleate are sequentially added to the slurry to adjust the pH value of the slurry to 9.5. Through a closed-circuit process of one roughing and two cleaning with middlings returning in sequence, a mixed flotation froth product and a mixed flotation sink product are obtained.

[0081] The mixed flotation froth product is filtered and dried, and then calcined at 600℃ for 4h to obtain a calcined product. The calcined product is ground to obtain a ground product; the particle size of the ground product is controlled to be 85wt% of-38μm.

[0082] The ground product is slurried to obtain a ground product slurry with a concentration of 60wt%. At 70℃, 0.5kg / t of sodium sulfide, 2.0kg / t of water glass, 0.15kg / t of sodium alginate, 0.8kg / t of o-hydroxy naphthalene carboxyhydroxamic acid, and 0.15kg / t of pine oil are sequentially added to the ground product slurry to adjust the pH value of the slurry to 9.0. A closed-circuit process of one roughing, two cleaning, and middlings sequentially returning is performed to obtain a rare earth concentrate and a rare earth tailing.

[0083] The rare earth tailing is slurried to obtain a rare earth tailing slurry with a concentration of 35wt%. At 30℃, 0.5kg / t of water glass, 0.25kg / t of tannin, and 0.4kg / t of sodium oleate are sequentially added to the rare earth tailing slurry to adjust the pH value of the slurry to 9.5. A closed-circuit process of one roughing, eight cleaning, and middlings combined returning roughing is performed to obtain a fluorite concentrate and a fluorite tailing.

[0084] The fluorite tailing is combined with the mixed flotation sink sand to obtain a final tailing.

[0085] Comparative Example 1

[0086] The difference from Example 1 is that the roasting and grinding process is omitted.

[0087] Comparative Example 2

[0088] The difference from Example 1 is that 2.0kg / t of water glass, 0.15kg / t of sodium alginate, 0.8kg / t of o-hydroxy naphthalene carboxyhydroxamic acid, and 0.15kg / t of pine oil are sequentially added to the ground product slurry. That is, sodium sulfide is omitted.

[0089] Example 2

[0090] The iron ore tailing of the Baotou Steel Baiyun Concentration Branch is used as the raw material, which has a TFe content of 13.36wt%, an REO content of 8.57wt%, a CaF2 content of 23.51wt%, a P2O5 content of 3.80wt%, and an S content of 1.88wt%.

[0091] The iron ore tailing is slurried to obtain a slurry with a concentration of 40wt%. At 35℃, 2.5kg / t of water glass and 0.5kg / t of sodium oleate are sequentially added to the slurry to adjust the pH value of the slurry to 9.0. A closed-circuit process of one roughing, two cleaning, and middlings sequentially returning is performed to obtain a mixed flotation froth product and a mixed flotation sink sand.

[0092] The mixed flotation froth product is filtered and dried, and is calcined at 550℃ for 4h to obtain a calcined product. The calcined product is ground to obtain a ground product; the particle size of the ground product is controlled to be 90wt% of the mass percentage of -38μm.

[0093] The iron ore tailings are slurried to obtain a slurry of the iron ore tailings having a concentration of 40wt%. At 35°C, 1.50kg / t of sodium silicate and 0.75kg / t of sodium oleate are sequentially added to the slurry, and the pH of the slurry is adjusted to 9.0. A closed-circuit process of one roughing, two cleaning, and middlings sequentially returning is performed to obtain a mixed flotation froth product and a mixed flotation sink product.

[0094] The mixed flotation froth product is filtered and dried, and is calcined at 580°C for 4h to obtain a calcined product. The calcined product is ground to obtain a ground product; the particle size of the ground product is controlled to have a mass percentage of -38μm of 90wt%.

[0095] The fluorite tailings are combined with the mixed flotation sink to obtain a final tailings.

[0096] Example 3

[0097] The iron ore tailings are slurried to obtain a slurry of the iron ore tailings having a concentration of 40wt%. At 35°C, 1.50kg / t of sodium silicate and 0.75kg / t of sodium oleate are sequentially added to the slurry, and the pH of the slurry is adjusted to 9.0. A closed-circuit process of one roughing, two cleaning, and middlings sequentially returning is performed to obtain a mixed flotation froth product and a mixed flotation sink product.

[0098] The mixed flotation froth product is filtered and dried, and is calcined at 580°C for 4h to obtain a calcined product. The calcined product is ground to obtain a ground product; the particle size of the ground product is controlled to have a mass percentage of -38μm of 90wt%.

[0099] The mixed flotation froth product is filtered and dried, and is calcined at 580°C for 4h to obtain a calcined product. The calcined product is ground to obtain a ground product; the particle size of the ground product is controlled to have a mass percentage of -38μm of 90wt%.

[0100] The mixed flotation froth product is filtered and dried, and is calcined at 580°C for 4h to obtain a calcined product. The calcined product is ground to obtain a ground product; the particle size of the ground product is controlled to have a mass percentage of -38μm of 90wt%.

[0101] The rare earth tailings are slurried to obtain a rare earth tailings slurry with a concentration of 37wt%. At 35°C, 0.50kg / t of water glass, 0.25kg / t of tannin, and 0.40kg / t of sodium oleate are sequentially added to the rare earth tailings slurry to adjust the pH value of the slurry to 9.0. A closed circuit process of one roughing and eight cleanings with middlings combined and returned to roughing is performed to obtain a fluorite concentrate and a fluorite tailings.

[0102] The fluorite tailings and the mixed flotation sinkers are combined to obtain a final tailings.

[0103] Example 4

[0104] The iron ore tailings from a beneficiation plant of Baogang are used as raw materials, which have a TFe content of 14.63wt%, a REO content of 6.88wt%, a CaF2 content of 20.38wt%, a P2O5 content of 3.74wt%, and a S content of 1.93wt%.

[0105] The iron ore tailings are slurried to obtain a slurry with a concentration of 38wt%. At 35°C, 3.0kg / t of water glass and 1.0kg / t of sodium oleate are sequentially added to the slurry to adjust the pH value of the slurry to 9.5. A closed circuit process of one roughing and two cleanings with middlings sequentially returned is performed to obtain a mixed flotation froth product and a mixed flotation sinker.

[0106] The mixed flotation froth product is filtered and dried, and is calcined at 600°C for 4h to obtain a calcined product. The calcined product is ground to obtain a ground product, and the particle size of the ground product is controlled to be 88wt% of the mass percentage of -38μm.

[0107] The ground product is slurried to obtain a ground product slurry with a concentration of 60wt%. At 80°C, 0.50kg / t of sodium sulfide, 2.0kg / t of water glass, 0.10kg / t of sodium alginate, 0.8kg / t of o-hydroxy naphthalene carboxyhydroxamic acid, and 0.20kg / t of pine oil are sequentially added to the ground product slurry to adjust the pH value of the slurry to 9.0. A closed circuit process of one roughing and two cleanings with middlings sequentially returned is performed to obtain a rare earth concentrate and a rare earth tailings.

[0108] The rare earth tailings are slurried to obtain a rare earth tailings slurry with a concentration of 38wt%. At 35°C, 0.50kg / t of water glass, 0.30kg / t of tannin, and 0.50kg / t of sodium oleate are sequentially added to the rare earth tailings slurry to adjust the pH value of the slurry to 9.0. A closed circuit process of one roughing and eight cleanings with middlings combined and returned to roughing is performed to obtain a fluorite concentrate and a fluorite tailings.

[0109] The fluorite tailings and the mixed flotation sinkers are combined to obtain a final tailings.

[0110] Table 1

[0111]

[0112] The present application is not limited to the above-described embodiments, and any modifications, improvements, substitutions, which can be conceived by those skilled in the art without departing from the essential content of the present application, fall within the scope of the present application.

Claims

1. A method of recovering selected iron tailings, characterized by, The method comprises the following steps: 1) slurry the iron ore tailings to obtain a slurry; add water glass, sodium oleate related substances to the slurry in sequence, and obtain a mixed flotation froth product and a mixed flotation sand through flotation; 2) filter the mixed flotation froth product to obtain a solid; dry the solid, and roast the solid at 400-650℃ to obtain a roasted product; grind the roasted product to obtain a ground product; 3) slurry the ground product to obtain a ground product slurry; add sodium sulfide, water glass, sodium alginate, hydroxamic acid and pine oil to the ground product slurry in sequence, and obtain a rare earth concentrate and a rare earth tailings through flotation; wherein, in step 1), the amount of water glass added is 0.1-6.0 kg / t based on the weight of the iron ore tailings; the amount of sodium oleate related substances added is 0.1-1.0 kg / t; in step 3), the amount of sodium sulfide added is 0.1-2.0 kg / t based on the weight of the iron ore tailings, the amount of water glass added is 0.1-6.0 kg / t, the amount of sodium alginate added is 0.01-0.3 kg / t, the amount of hydroxamic acid added is 0.1-1.5 kg / t, and the amount of pine oil added is 0.03-0.20 kg / t; the hydroxamic acid is at least one selected from salicylhydroxamic acid and o-hydroxynaphthalene carboxyhydroxamic acid; the sodium oleate related substances are selected from sodium oleate or a modified product of sodium oleate. In the iron ore tailings, the content of TFe is 10-15 wt%, the content of REO is 7-10 wt%, the content of CaF2 is 20-25 wt%, the content of P2O5 is 2.5-6.5 wt%, and the content of S is 1.5-3.0 wt%.

2. The recycling method according to claim 1, characterized in that, In step 1), the concentration of the slurry is 30-45 wt%; during flotation, the pH value of the slurry is adjusted to 8-9.5; and the flotation temperature is 20-35℃.

3. The recycling method of claim 1, wherein, In step 2), the roasting time is 1-5 h; and the particle size of the ground product is controlled to have a mass percentage of 80-90 wt% of -38 μm.

4. The recycling method of claim 1, wherein, In step 3), the concentration of the ground product slurry is 50-70 wt%; during flotation, the pH value of the ground product slurry is adjusted to 8-9; and the flotation temperature is 50-90℃.

5. The recycling method of claim 1, wherein, The method further comprises the following steps:

6. The recycling method according to any one of claims 1 to 5, characterized in that, 4) slurry the rare earth tailings to obtain a rare earth tailings slurry; add water glass, a polyphenol derivative, sodium oleate related substances to the rare earth tailings slurry in sequence, and obtain a fluorite concentrate and a fluorite tailings through one roughing and multiple cleaning flotation; wherein, the amount of water glass added is 0.1-6.0 kg / t based on the weight of the iron ore tailings, the amount of polyphenol derivative added is 0.05-1.0 kg / t, and the amount of sodium oleate related substances added is 0.1-1.0 kg / t. In step 4), the concentration of the rare earth tailings slurry is 30-45 wt%; during flotation, the pH value of the rare earth tailings slurry is adjusted to 8-9.5; and the flotation temperature is 20-40℃.

7. The recycling method according to claim 6, characterized in that, In steps 1) and 4), the sodium oleate related substances are sodium oleate; and the polyphenol derivative is at least one selected from tannin, tannin extract, and gallic acid.

8. The recycling method of claim 6, wherein, The method further comprises the following steps:

9. The recycling method of claim 6, wherein, combine the fluorite tailings with the mixed flotation sand to obtain a final tailings. ​

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