Ore dressing method for mixed rare earth ore

Abstract

The present invention discloses a beneficiation method for a mixed rare earth ore, comprising the following steps: subjecting the ground mixed rare earth ore to magnetic separation to obtain a magnetic separation concentrate and a magnetic separation tailing; wherein, the mixed rare earth ore contains parisite and bastnaesite; subjecting the magnetic separation concentrate to a first flotation in the presence of a pH regulator A, an inhibitor A, a collector A and a frother A to obtain a first flotation concentrate and a first flotation tailing; wherein, the inhibitor A includes water glass, phosphate and starch, the collector A includes hydroxamic acid and styrylphenol polyoxyethylene ether, and the frother A is a fatty alcohol frother; grinding the first flotation tailing to obtain the ground first flotation tailing; subjecting the ground first flotation tailing to a second flotation in the presence of a pH regulator B, an inhibitor B, a collector B and a frother B to obtain a second flotation concentrate. The beneficiation method of the present invention can improve the rare earth grade of the mixed rare earth ore containing parisite and bastnaesite.

Description

Technical Field

[0001] The present invention relates to a beneficiation method for a mixed rare earth ore. Background Art

[0002] Rare earth elements include lanthanide elements, yttrium and scandium. These elements have unique spatial structures and physicochemical properties, making them indispensable in various high-tech fields. Rare earth elements are known as the "industrial vitamins" and are the basic raw materials for many key and advanced technology applications. Rare earth elements usually exist in nature in the forms of bastnaesite, monazite and xenotime. Carboantzenite [(Ce,Na,Sr,Ca)CO 3 often appears in carbonate rocks and alkaline rocks, especially in areas related to hydrothermal activities, and is usually symbiotic with other rare earth minerals such as parisite, bastnaesite and apatite. At present, the research on enriching rare earth element resources mainly focuses on bastnaesite, monazite and xenotime, while the related research on carboantzenite is less.

[0003] CN103962232A discloses a beneficiation method for rare earth ores. The original ore is ground to a fineness where -2.00 mm accounts for 100%, and is classified into three particle sizes: -2.00 + 0.65 mm, -0.65 + 0.074 mm, and -0.074 mm. The product of the -2.00 + 0.65 mm particle size is beneficiated by a spiral concentrator to obtain a spiral concentrator beneficiation concentrate and a spiral concentrator beneficiation tailing. The product of the -0.65 + 0.074 mm particle size is beneficiated by a spiral chute to obtain a spiral chute beneficiation concentrate and a spiral chute beneficiation tailing. The product of the -0.074 mm particle size is beneficiated by magnetic separation under the condition that the magnetic field intensity is 1.0 - 1.5 T to obtain a strong magnetic separation concentrate and a strong magnetic separation tailing. The spiral concentrator beneficiation concentrate, the spiral chute beneficiation concentrate, and the strong magnetic separation concentrate are respectively beneficiated by a shaking table to obtain a shaking table concentrate, a shaking table middling, and a shaking table tailing. The shaking table concentrates and shaking table middlings of each particle size are combined and subjected to wet high-gradient magnetic separation under a magnetic field intensity of 0.4 - 0.9 T to obtain a magnetic separation rare earth concentrate and a magnetic separation rare earth middling. The magnetic separation middling and the shaking table tailing are combined and reground to a fineness where -0.043 mm accounts for 50 - 85% and the pulp concentration is 20 - 45%. Per ton of the original ore, 1000 - 3000 g of a regulator is added for pulp conditioning, 1000 - 2500 g of a collector, and 30 - 80 g of a foaming agent kerosene are added for rough flotation to obtain a rough flotation concentrate and a rough flotation tailing. The rough flotation tailing has a pulp concentration of 20 - 35%, 1000 - 1500 g of a collector and 5 - 40 g of a foaming agent kerosene are added for one scavenging to obtain a one scavenging concentrate and a one scavenging tailing, and the one scavenging concentrate is returned to the rough flotation operation to form a closed circuit. The one scavenging tailing has a pulp concentration of 20 - 35%, 400 - 800 g of a collector is added for two scavenging to obtain a two scavenging concentrate and a two scavenging tailing, and the two scavenging concentrate is returned to the one scavenging operation to form a closed circuit. The rough flotation concentrate has a pulp concentration of 10 - 20%, 400 - 800 g of a collector is added for two scavenging to obtain a two scavenging concentrate and a two scavenging tailing, and the two scavenging concentrate is returned to the one scavenging operation to form a closed circuit. The rough flotation concentrate has a pulp concentration of 10 - 20%, 400 - 800 g of a regulator is added for one cleaning to obtain a one cleaning concentrate and a one cleaning tailing, and the one cleaning tailing is returned to the rough flotation operation to form a closed circuit. The one cleaning concentrate has a pulp concentration of 3 - 15%, 200 - 600 g of a regulator is added for two cleaning to obtain a flotation rare earth concentrate and a two cleaning tailing, and the two cleaning tailing is returned to the one cleaning operation to form a closed circuit. The magnetic separation rare earth concentrate and the flotation rare earth concentrate are the total rare earth concentrates. This method is mainly applicable to mixed rare earth ores containing bastnaesite, parisite, and monazite.

[0004] CN102500465A discloses a beneficiation method for bastnasite. The original ore is ground to -1.0 mm and classified into three particle sizes: -1.0 + 0.4 mm, -0.4 + 0.074 mm, and -0.074 mm. Magnetic separation is carried out under the condition that the background magnetic field intensity is 1.0 T to obtain strong magnetic separation concentrate and strong magnetic separation tailings. The strong magnetic separation concentrates of each particle size are respectively subjected to shaking table gravity separation to obtain shaking table concentrate, shaking table middlings, and shaking table tailings. The shaking table concentrates and shaking table middlings of each particle size are combined and subjected to wet high-gradient magnetic separation under the condition that the rated background magnetic field intensity is 0.5 - 0.8 T to obtain magnetic separation bastnasite concentrate and magnetic separation middlings. The magnetic separation middlings and shaking table tailings are combined, reground to -0.043 mm accounting for 50 - 75%, and the pulp concentration is 25 - 35%. Based on per ton of the original ore, 1000 - 3000 g of regulator is added in sequence to adjust the pulp, 3000 - 5000 g of collector, and 10 - 100 g of frother No. 2 oil for rough flotation to obtain rough flotation concentrate and rough flotation tailings. The pulp concentration of the rough flotation tailings is 20 - 30%, 1000 - 1500 g of collector and 5 - 40 g of frother No. 2 oil are added for one scavenging to obtain one scavenging concentrate and one scavenging tailings. The one scavenging concentrate is returned to the rough flotation operation to form a closed circuit. The pulp concentration of the one scavenging tailings is 20 - 35%, 400 - 800 g of collector is added for two scavenging; two scavenging concentrate and two scavenging tailings are obtained, and the two scavenging concentrate is returned to the two scavenging operation to form a closed circuit. The pulp concentration of the rough flotation concentrate is 10 - 30%, 400 - 1000 g of regulator is added for one cleaning to obtain one cleaning concentrate and one cleaning tailings. The one cleaning tailings are returned to the rough flotation operation to form a closed circuit. The pulp concentration of the one cleaning concentrate is 10 - 25%, 200 - 800 g of regulator is added for two cleaning to obtain two cleaning concentrate and two cleaning tailings. The two cleaning tailings are returned to the one cleaning operation to form a closed circuit. The pulp concentration of the two cleaning concentrate is 5 - 20%, 100 - 400 g of regulator is added for three cleaning to obtain flotation bastnasite concentrate and three cleaning tailings. The three cleaning tailings are returned to the two cleaning operation to form a closed circuit. The above method is applicable to bastnasite. Summary of the Invention

[0005] One object of the present invention is to provide a beneficiation method for a mixed rare earth ore. The beneficiation method of the present invention can effectively improve the rare earth grade of the mixed rare earth ore containing parisite and bastnasite. Further, the rare earth recovery rate of the beneficiation method is relatively high. The object of the present invention is achieved through the following technical solutions.

[0006] The present invention provides a beneficiation method for a mixed rare earth ore, including the following steps:

[0007] (1) Magnetic separation is carried out on the ground mixed rare earth ore to obtain magnetic separation concentrate and magnetic separation tailings; wherein, the mixed rare earth ore contains parisite and bastnaesite.

[0008] (2) The magnetic separation concentrate is subjected to the first flotation in the presence of pH regulator A, inhibitor A, collector A and frother A to obtain the first flotation concentrate and the first flotation tailings.

[0009] Among them, the inhibitor A includes sodium silicate, phosphate and starch with a mass ratio of (4-8):(1-5):(0.5-3), the collector A includes hydroxamic acid with C5-C10 and styrylphenol polyoxyethylene ether with a mass ratio of (7-11):(0.5-3), and the frother A is a fatty alcohol frother.

[0010] (3) The first flotation tailings are ground to obtain the ground first flotation tailings.

[0011] (4) The ground first flotation tailings are subjected to the second flotation in the presence of pH regulator B, inhibitor B, collector B and frother B to obtain the second flotation concentrate and the second flotation tailings.

[0012] Among them, the inhibitor B includes sodium silicate, phosphate and starch with a mass ratio of (4-8):(1-5):(0.5-3), the collector B includes hydroxamic acid with C5-C10 and styrylphenol polyoxyethylene ether with a mass ratio of (7-11):(0.5-3), and the frother B is a fatty alcohol frother.

[0013] According to the ore dressing method of the present invention, preferably, step (1) includes the following steps:

[0014] The ground mixed rare earth ore is subjected to rough magnetic separation to obtain rough magnetic separation concentrate and rough magnetic separation tailings; wherein, the rough magnetic separation field intensity is 1.1-1.5T, the feed concentration is 10-30wt%, and the pulse frequency is 12-16Hz.

[0015] The rough magnetic separation tailings are subjected to scavenging magnetic separation to obtain scavenging magnetic separation concentrate and magnetic separation tailings; wherein, the scavenging magnetic separation field intensity is 1.6-2.0T, the feed concentration is 10-30wt%, and the pulse frequency is 13-20Hz.

[0016] The rough magnetic separation concentrate and the scavenging magnetic separation concentrate are combined to obtain magnetic separation concentrate.

[0017] The fineness of the ground mixed rare earth ore with a particle size below 0.074mm accounts for 75-100wt%.

[0018] For the ore dressing method according to the present invention, preferably, the modulus of the water glass is 2 to 3, the phosphate is selected from one or more of sodium hexametaphosphate and trisodium phosphate, the hydroxamic acid is a C7-9 hydroxamic acid, the styrylphenol polyoxyethylene ether is selected from one or more of agricultural emulsion 601, agricultural emulsion 602, agricultural emulsion 603, and agricultural emulsion 604, the fatty alcohol foaming agent is an aliphatic monohydric alcohol containing C4-C10, the pH regulator A is a carbonate, and the pH regulator B is a carbonate.

[0019] For the ore dressing method according to the present invention, preferably, step (2) includes the following steps:

[0020] Form a magnetic separation concentrate pulp with a concentration of 45-65 wt%; at 50-70 °C, add pH regulator A, inhibitor A, collector A, and foaming agent A to the magnetic separation concentrate pulp for the first rough flotation to obtain the first rough flotation concentrate and the first rough flotation tailings; wherein, based on the weight of the feed ore, the dosage of the pH regulator is 1.0-2.0 kg / T, the dosage of the inhibitor is 1.5-2.5 kg / T, the dosage of the collector is 0.9-1.5 kg / T, and the dosage of the foaming agent is 0.1-0.3 kg / T;

[0021] Perform N-stage first flotation cleaning on the first rough flotation concentrate to obtain the first flotation concentrate; N is an integer greater than or equal to 2;

[0022] Among them, the first-stage first flotation cleaning includes the following steps: form a first rough flotation concentrate pulp from the first rough flotation concentrate; add pH regulator A, inhibitor A, collector A, and foaming agent A to the first rough flotation concentrate pulp for the first-stage first flotation cleaning to obtain the first-stage first flotation cleaning concentrate and the first-stage first flotation cleaning tailings; the first-stage first flotation cleaning tailings are returned to the first rough flotation as raw materials; based on the weight of the feed ore, the dosage of pH regulator A is 0.2-0.6 kg / T, the dosage of inhibitor A is 0.4-0.9 kg / T, the dosage of collector A is 0.1-0.5 kg / T, and the dosage of foaming agent A is 0.01-0.2 kg / T;

[0023] Among them, the second-stage first flotation cleaning to the N-stage first flotation cleaning respectively include the following steps:

[0024] The m-1st stage first flotation cleaning concentrate is formed into the m-1st stage first flotation cleaning concentrate pulp; pH regulator A, inhibitor A, collector A and frother A are added to the m-1st stage first flotation cleaning concentrate pulp for the mth stage first flotation cleaning to obtain the mth stage first flotation cleaning concentrate and the mth stage first flotation cleaning tailings; the mth stage first flotation cleaning tailings are returned to the m-1st stage first flotation cleaning as raw materials; based on the weight of the feed, the dosage of pH regulator A is 0.05 - 0.25 kg / T, the dosage of inhibitor A is 0.10 - 0.35 kg / T, the dosage of collector A is 0.05 - 0.25 kg / T, and the dosage of frother A is 0.005 - 0.035 kg / T; wherein, m is an integer greater than or equal to 2 and less than or equal to N, and the Nth stage first flotation cleaning concentrate is the first flotation concentrate.

[0025] According to the ore dressing method of the present invention, preferably, in step (2), the materials are added in sequence according to the order of pH regulator A, inhibitor A, collector A and frother A, and the feeding interval time between each material is 2 - 5 min;

[0026] Wherein, the following formula is used to calculate the feeding interval time:

[0027] t=t 1 -t 2 ;

[0028] Wherein, t represents the feeding interval time, t 1 represents the time when the latter material starts to be added, and t 2 represents the time when the previous material is added completely.

[0029] According to the ore dressing method of the present invention, preferably, in step (3), the grinding concentration is 50 - 65 wt%, and the fineness of the first flotation tailings after grinding with a particle size below 0.03 mm accounts for 85 - 100 wt%.

[0030] According to the ore dressing method of the present invention, preferably, step (4) includes the following steps:

[0031] The first flotation tailings after grinding are formed into the first flotation tailings pulp with a concentration of 40 - 65 wt%; at 50 - 70 °C, pH regulator B, inhibitor B, collector B and frother B are added to the first flotation tailings pulp for the second flotation roughing to obtain the second flotation roughing concentrate and the second flotation tailings; wherein, based on the weight of the feed, the dosage of pH regulator B is 0.6 - 1.3 kg / T, the dosage of inhibitor B is 0.8 - 1.6 kg / T, the dosage of collector B is 0.5 - 1.1 kg / T, and the dosage of frother B is 0.1 - 0.5 kg / T;

[0032] The second rough flotation concentrate is subjected to the first-stage second flotation cleaning to obtain the second flotation concentrate; I is an integer greater than or equal to 2;

[0033] Among them, the first-stage second flotation cleaning includes the following steps:

[0034] The second rough flotation concentrate is formed into a second rough flotation concentrate pulp; a pH regulator B, an inhibitor B, a collector B, and a foaming agent B are added to the second rough flotation concentrate pulp for the first-stage second flotation cleaning to obtain a first-stage second flotation cleaning concentrate and a first-stage second flotation cleaning tailings; the first-stage second flotation cleaning tailings are returned to the second rough flotation as raw materials; based on the weight of the feed, the dosage of the pH regulator B is 0.2 - 0.5 kg / T, the dosage of the inhibitor B is 0.2 - 0.6 kg / T, the dosage of the collector B is 0.1 - 0.5 kg / T, and the dosage of the foaming agent B is 0.01 - 0.15 kg / T;

[0035] Among them, the second-stage second flotation cleaning to the I-stage second flotation cleaning respectively include the following steps:

[0036] The (j - 1)-stage second flotation cleaning concentrate is formed into a (j - 1)-stage second flotation cleaning concentrate pulp; a pH regulator B, an inhibitor B, a collector B, and a foaming agent B are added to the (j - 1)-stage second flotation cleaning concentrate pulp for the j-stage second flotation cleaning to obtain a j-stage second flotation cleaning concentrate and a j-stage second flotation cleaning tailings; the j-stage second flotation cleaning tailings are returned to the (j - 1)-stage second flotation cleaning as raw materials; based on the weight of the feed, the dosage of the pH regulator B is 0.05 - 0.30 kg / T, the dosage of the inhibitor B is 0.08 - 0.35 kg / T, the dosage of the collector B is 0.05 - 0.25 kg / T, and the dosage of the foaming agent B is 0.005 - 0.07 kg / T; where j is an integer greater than or equal to 2 and less than or equal to I, and the I-stage second flotation cleaning concentrate is the second flotation concentrate.

[0037] According to the ore dressing method of the present invention, preferably, in step (4), the pH regulator B, the inhibitor B, the collector B, and the foaming agent B are added in sequence, and the feeding interval time between each material is 2 - 5 min;

[0038] Among them, the following formula is used to calculate the feeding interval time:

[0039] t = t 1 - t 2 ;

[0040] Among them, t represents the feeding interval time, t 1 represents the time when the latter material starts to be added, and t 2 represents the time when the previous material is added completely.

[0041] The beneficiation method according to the present invention preferably includes the following steps:

[0042] Merge the first flotation concentrate and the second flotation concentrate to obtain a rare earth concentrate.

[0043] The beneficiation method according to the present invention preferably further includes the following steps:

[0044] Crush the mixed rare earth ore to obtain crushed ore; grind the crushed ore to obtain the ground mixed rare earth ore;

[0045] The mass ratio of parisite and bastnäsite in the mixed rare earth ore is (3 - 6.5):(2 - 5.5), and the mixed rare earth ore further contains at least one of calcite, mica, feldspar and apatite.

[0046] The beneficiation method of the present invention can enrich parisite and bastnäsite in the mixed rare earth ore to obtain a rare earth concentrate with a high rare earth grade. Further, the beneficiation method of the present invention has a high rare earth recovery rate. Detailed Embodiments

[0047] The following further illustrates the present invention with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0048] The beneficiation method of the mixed rare earth ore of the present invention includes the following steps: (1) a magnetic separation step; (2) a first flotation step; (3) a grinding step of the first flotation tailings; and (4) a second flotation step. In some embodiments, it further includes the steps of crushing and grinding the mixed rare earth concentrate. The following describes each step in detail.

[0049] Magnetic Separation Step

[0050] The present invention subjects the ground mixed rare earth ore to magnetic separation to obtain a magnetic separation concentrate and a magnetic separation tailings.

[0051] The mixed rare earth ore of the present invention includes parisite and bastnäsite. The mass ratio of parisite and bastnäsite is (3 - 6.5):(2 - 5.5); preferably (4 - 6):(3 - 5). In some embodiments, the mass ratio of parisite and bastnäsite is (4.5 - 5):(3.5 - 4).

[0052] The rare earth grade of the mixed rare earth ore can be 2.5 - 5.5 wt%; preferably 3 - 4.5 wt%. In some embodiments, the rare earth grade of the mixed rare earth ore is 3.5 - 3.8 wt%.

[0053] The mixed rare earth ore also contains gangue minerals. The gangue minerals are selected from at least one of calcite, mica, feldspar, and apatite. In the mixed rare earth ore, the content of calcite can be 35-55 wt%; preferably 40-50 wt%; more preferably 42-46 wt%.

[0054] The fineness of the ground mixed rare earth ore with a particle size below 0.074 mm accounts for 75-100 wt%; preferably, it accounts for 80-95 wt%; more preferably, it accounts for 85-90 wt%.

[0055] In the ground mixed rare earth ore, the monomer dissociation degree of parisite can be 75-90 wt%. In some embodiments, the monomer dissociation degree of parisite is 80-87 wt%.

[0056] In the ground mixed rare earth ore, the monomer dissociation degree of bastnasite can be 20-35 wt%. In some embodiments, the monomer dissociation degree of bastnasite is 24-30 wt%.

[0057] Specifically, it includes the following steps: subjecting the ground mixed rare earth ore to rough magnetic separation to obtain a rough magnetic separation concentrate and a rough magnetic separation tailing; subjecting the rough magnetic separation tailing to scavenging magnetic separation to obtain a scavenging magnetic separation concentrate and a magnetic separation tailing; and combining the rough magnetic separation concentrate and the scavenging magnetic separation concentrate to obtain a magnetic separation concentrate.

[0058] The parameters of the rough magnetic separation are as follows:

[0059] The magnetic field intensity of the rough magnetic separation can be 1.1-1.5 T; preferably 1.2-1.4 T; more preferably 1.2-1.3 T.

[0060] The feed concentration can be 10-30 wt%; preferably 15-25 wt%; more preferably 20-22 wt%.

[0061] The pulse frequency can be 12-16 Hz; preferably 13-15 Hz; more preferably 14-15 Hz.

[0062] The parameters of the scavenging magnetic separation are as follows:

[0063] The magnetic field intensity of the scavenging magnetic separation can be 1.6-2.0 T; preferably 1.7-1.9 T; more preferably 1.7-1.8 T.

[0064] The feed concentration can be 10-30 wt%; preferably 15-25 wt%; more preferably 20-22 wt%.

[0065] The pulse frequency can be 13-20 Hz; preferably 15-19 Hz; more preferably 17-18 Hz.

[0066] Steps of the first flotation

[0067] The magnetic separation concentrate is subjected to a first flotation in the presence of pH regulator A, inhibitor A, collector A, and frother A to obtain a first flotation concentrate and a first flotation tailing. The letter A contained in the foregoing materials has no special meaning, and is only used to distinguish from the materials used in the second flotation step below.

[0068] The pH regulator A can be a carbonate; preferably an alkali metal carbonate. For example, sodium carbonate, potassium carbonate. According to an embodiment of the present invention, the pH regulator A is potassium carbonate.

[0069] The inhibitor A includes water glass, phosphate, and starch. The mass ratio of water glass, phosphate, and starch can be (4-8):(1-5):(0.5-3); preferably (5-7):(2-4):(0.8-2); more preferably (6-6.5):(3-3.5):(1-1.5).

[0070] The modulus of the water glass can be 2-3; preferably 2.2-2.8; more preferably 2.4-2.6.

[0071] The phosphate can be selected from one or more of sodium hexametaphosphate and trisodium phosphate; preferably sodium hexametaphosphate.

[0072] The collector A includes hydroxamic acid and styrylphenol polyoxyethylene ether. The mass ratio of hydroxamic acid and styrylphenol polyoxyethylene ether can be (7-11):(0.5-3); preferably (8-10):(0.5-2); more preferably (9-9.5):(1-1.5).

[0073] The hydroxamic acid can be selected from hydroxamic acids having C5-C10; preferably selected from hydroxamic acids having C7-C9; more preferably selected from hydroxamic acids having C8; most preferably, it is octyl hydroxamic acid.

[0074] The styrylphenol polyoxyethylene ether can be selected from one or more of agricultural emulsifier 601, agricultural emulsifier 602, agricultural emulsifier 603, and agricultural emulsifier 604; preferably, it is agricultural emulsifier 601.

[0075] The frother A is a fatty alcohol frother; preferably a fatty monohydric alcohol containing C4-C10; more preferably a fatty monohydric alcohol containing C6-C8; most preferably, the frother A is methyl isobutyl carbinol.

[0076] Specifically, it includes the following steps: forming a magnetic separation concentrate pulp, adding pH regulator A, inhibitor A, collector A, and frother A to the magnetic separation concentrate pulp for the first rough flotation to obtain a first rough flotation concentrate and a first rough flotation tailing; subjecting the first rough flotation concentrate to N-stage first fine flotation to obtain a first fine flotation concentrate. N is an integer greater than or equal to 2; preferably, N is an integer greater than or equal to 3 and less than or equal to 5; most preferably, N is 3.

[0077] The concentration of the magnetic separation concentrate pulp can be 45 - 65 wt%; preferably 50 - 60 wt%; more preferably 55 - 60 wt%.

[0078] The temperature of the first rough flotation can be 50 - 70 °C; preferably 55 - 65 °C; more preferably 60 - 65 °C.

[0079] Based on the weight of the feed ore, the dosage of pH regulator A in the first rough flotation step can be 1.0 - 2.0 kg / T; preferably 1.2 - 1.8 kg / T; more preferably 1.4 - 1.6 kg / T.

[0080] Based on the weight of the feed ore, the dosage of inhibitor A in the first rough flotation step can be 1.5 - 2.5 kg / T; preferably 1.7 - 2.3 kg / T; more preferably 2 - 2.2 kg / T.

[0081] Based on the weight of the feed ore, the dosage of collector A in the first rough flotation step is 0.9 - 1.5 kg / T; preferably 1 - 1.3 kg / T; more preferably 1.1 - 1.2 kg / T.

[0082] Based on the weight of the feed ore, the dosage of frother A in the first rough flotation step is 0.1 - 0.3 kg / T; preferably 0.15 - 0.25 kg / T; more preferably 0.18 - 0.2 kg / T.

[0083] In the first rough flotation step, the materials can be added to the magnetic separation concentrate pulp in the order of pH regulator A, inhibitor A, collector A, and frother A.

[0084] The feeding interval time between each material is 2 - 5 min; preferably 3 - 4 min. The feeding interval time is calculated using the following formula: t = t 1 -t 2 . t represents the feeding interval time. t 1 represents the time when the latter material starts to be added. t 2 represents the time when the former material is added completely.

[0085] Specifically, the first-stage first flotation concentration includes the following steps: forming a first flotation rough concentrate pulp from the first flotation rough concentrate; adding pH regulator A, inhibitor A, collector A, and frother A to the first flotation rough concentrate pulp for the first-stage first flotation concentration to obtain a first-stage first flotation concentrated concentrate and a first-stage first flotation concentrated tailings; returning the first-stage first flotation concentrated tailings to the first flotation roughing as raw materials for use.

[0086] Based on the feed weight, the dosage of pH regulator A in the first-stage first flotation concentration step is 0.2 - 0.6 kg / T; preferably 0.3 - 0.5 kg / T; more preferably 0.4 - 0.45 kg / T.

[0087] Based on the feed weight, the dosage of inhibitor A in the first-stage first flotation concentration step is 0.4 - 0.9 kg / T; preferably 0.5 - 0.8 kg / T; more preferably 0.6 - 0.7 kg / T.

[0088] Based on the feed weight, the dosage of collector A in the first-stage first flotation concentration step is 0.1 - 0.5 kg / T; preferably 0.2 - 0.45 kg / T; more preferably 0.3 - 0.4 kg / T.

[0089] Based on the feed weight, the dosage of frother A in the first-stage first flotation concentration step is 0.01 - 0.2 kg / T; preferably 0.03 - 0.1 kg / T; more preferably 0.05 - 0.08 kg / T.

[0090] In the first-stage first flotation concentration step, the materials can be added to the first flotation rough concentrate pulp in the order of pH regulator A, inhibitor A, collector A, and frother A.

[0091] The feeding interval time between each material is 2 - 5 min; preferably 3 - 4 min. The feeding interval time is calculated using the following formula: t = t 1 -t 2 . t represents the feeding interval time. t 1 represents the time when the latter material starts to be added. t 2 represents the time when the former material is added completely.

[0092] The concentration of the first flotation rough concentrate pulp can be 40 - 70 wt%; preferably 45 - 65 wt%; more preferably 50 - 60 wt%.

[0093] The temperature of the first-stage first flotation concentration can be 35 - 65 °C; preferably 40 - 60 °C; more preferably 50 - 55 °C.

[0094] Specifically, the second-stage first flotation concentrate to the N-stage first flotation concentration respectively include the following steps:

[0095] The m-1st stage first flotation concentrate is formed into an m-1st stage first flotation concentrate pulp; pH regulator A, inhibitor A, collector A, and foaming agent A are added to the m-1st stage first flotation concentrate pulp for the mth stage first flotation cleaning to obtain the mth stage first flotation cleaning concentrate and the mth stage first flotation cleaning tailings; the mth stage first flotation cleaning tailings are returned to the m-1st stage first flotation cleaning as raw materials. m is an integer greater than or equal to 2 and less than or equal to N, and the Nth stage first flotation cleaning concentrate is the first flotation concentrate.

[0096] Based on the weight of the feed ore, the dosage of pH regulator A in the mth stage first flotation cleaning step can be 0.05 - 0.25 kg / T; preferably 0.10 - 0.20 kg / T; more preferably 0.12 - 0.16 kg / T.

[0097] Based on the weight of the feed ore, the dosage of inhibitor A in the mth stage first flotation cleaning step can be 0.10 - 0.35 kg / T; preferably 0.15 - 0.30 kg / T; more preferably 0.20 - 0.25 kg / T.

[0098] Based on the weight of the feed ore, the dosage of collector A in the mth stage first flotation cleaning step can be 0.05 - 0.25 kg / T; preferably 0.10 - 0.20 kg / T; more preferably 0.12 - 0.15 kg / T.

[0099] Based on the weight of the feed ore, the dosage of foaming agent A in the mth stage first flotation cleaning step can be 0.005 - 0.035 kg / T; preferably 0.010 - 0.030 kg / T; more preferably 0.015 - 0.020 kg / T.

[0100] In the mth stage first flotation cleaning step, the materials can be added to the m-1st stage first flotation concentrate pulp in the order of pH regulator A, inhibitor A, collector A, and foaming agent A.

[0101] The feeding interval time between each material is 2 - 5 min; preferably 3 - 4 min. The feeding interval time is calculated using the following formula: t = t 1 -t 2 . t represents the feeding interval time. t 1 represents the time when the latter material starts to be added. t 2 represents the time when the previous material is added completely.

[0102] The concentration of the m-1st stage first flotation concentrate pulp can be 35 - 65 wt%; preferably 40 - 60 wt%; more preferably 45 - 50 wt%.

[0103] The temperature of the first flotation concentration for the m level can be 35 - 65 °C; preferably 45 - 60 °C; more preferably 50 - 55 °C.

[0104] Preferably, N is 3. That is, the first flotation concentration is carried out in three stages.

[0105] Steps of grinding the first flotation tailings

[0106] In the present invention, the first flotation tailings are ground to obtain the ground first flotation tailings.

[0107] The fineness of the ground first flotation tailings is such that the proportion of particles below 0.03 mm is 85 - 100 wt%; preferably 90 - 97 wt%.

[0108] The grinding concentration can be 50 - 65 wt%; preferably 55 - 60 wt%.

[0109] In the ground first flotation tailings, the monomer dissociation degree of bastnaesite is 70 - 90 wt%; preferably 75 - 85 wt%.

[0110] Steps of the second flotation

[0111] In the present invention, the ground first flotation tailings are subjected to the second flotation in the presence of pH regulator B, inhibitor B, collector B, and frother B to obtain the second flotation concentrate and the second flotation tailings. Material A and Material B can be the same or different; when Material A and Material B are the same, the appended letters can be removed. For example, when pH regulator A and pH regulator B are the same, they can be collectively referred to as pH regulator.

[0112] pH regulator B can be a carbonate; preferably an alkali metal carbonate. For example, sodium carbonate, potassium carbonate. According to one embodiment of the present invention, pH regulator B is potassium carbonate.

[0113] Inhibitor B includes water glass, phosphate, and starch. The mass ratio of water glass, phosphate, and starch can be (4 - 8):(1 - 5):(0.5 - 3); preferably (5 - 7):(2 - 4):(0.8 - 2); more preferably (6 - 6.5):(3 - 3.5):(1 - 1.5).

[0114] The modulus of water glass can be 2 - 3.5; preferably 2.2 - 2.8; more preferably 2.4 - 2.6.

[0115] Phosphate can be selected from one or more of sodium hexametaphosphate and trisodium phosphate; preferably sodium hexametaphosphate.

[0116] The collector B includes hydroxamic acid and styrylphenol polyoxyethylene ether. The mass ratio of hydroxamic acid to styrylphenol polyoxyethylene ether can be (7 - 11):(0.5 - 3); preferably (8 - 10):(0.5 - 2); more preferably (9 - 9.5):(1 - 1.5).

[0117] The hydroxamic acid can be selected from hydroxamic acids with C5 - C10; preferably selected from hydroxamic acids with C7 - C9; more preferably selected from hydroxamic acid with C8; most preferably, it is octyl hydroxamic acid.

[0118] The styrylphenol polyoxyethylene ether can be selected from one or more of agricultural emulsifier 601, agricultural emulsifier 602, agricultural emulsifier 603, and agricultural emulsifier 604; preferably, it is agricultural emulsifier 601.

[0119] The foaming agent B is a fatty alcohol foaming agent; preferably, it is a monohydric aliphatic alcohol containing C4 - C10; more preferably, it is a monohydric aliphatic alcohol containing C6 - C8; most preferably, the foaming agent B is methyl isobutyl carbinol.

[0120] Specifically, it includes the following steps: forming a first flotation tailings pulp from the first flotation tailings after grinding; adding a pH regulator B, an inhibitor B, a collector B, and a foaming agent B to the first flotation tailings pulp for a second rough flotation to obtain a second rough flotation concentrate and a second flotation tailings; subjecting the second rough flotation concentrate to a first-stage second flotation cleaning, where I is an integer greater than or equal to 2; preferably, I is an integer greater than or equal to 3 and less than or equal to 5; most preferably, I is 3.

[0121] The concentration of the first flotation tailings pulp can be 40 - 65 wt%; preferably 45 - 60 wt%. In some embodiments, the concentration of the first flotation tailings pulp is 50 - 55 wt%.

[0122] The temperature of the second rough flotation can be 50 - 70 °C; preferably 55 - 65 °C; more preferably 60 - 65 °C.

[0123] Based on the weight of the feed ore, the dosage of the pH regulator B in the second rough flotation step can be 0.6 - 1.3 kg / T; preferably 0.8 - 1.1 kg / T. In some embodiments, the dosage is 0.8 - 0.9 kg / T.

[0124] Based on the weight of the feed ore, the dosage of the inhibitor B in the second rough flotation step can be 0.8 - 1.6 kg / T; preferably 1.0 - 1.3 kg / T. In some embodiments, the dosage is 1.1 - 1.2 kg / T.

[0125] Based on the feed weight, the dosage of collector B in the second rough flotation step is 0.5 - 1.1 kg / T; preferably 0.7 - 1 kg / T; more preferably 0.75 - 0.9 kg / T.

[0126] Based on the feed weight, the dosage of frother B in the second rough flotation step is 0.1 - 0.5 kg / T; preferably 0.15 - 0.3 kg / T; more preferably 0.2 - 0.25 kg / T.

[0127] In the second rough flotation step, materials can be added to the ground pulp of the first flotation tailings in the order of pH regulator B, inhibitor B, collector B, and frother B.

[0128] The feeding interval time between each material is 2 - 5 min; preferably 3 - 4 min. The feeding interval time is calculated using the following formula: t = t 1 -t 2 . t represents the feeding interval time. t 1 represents the time when the latter material starts to be added. t 2 represents the time when the previous material is added completely.

[0129] Specifically, the first-stage second flotation cleaning includes the following steps: forming the pulp of the second rough flotation concentrate; adding pH regulator B, inhibitor B, collector B, and frother B to the pulp of the second rough flotation concentrate for the first-stage second flotation cleaning to obtain the first-stage second flotation cleaning concentrate and the first-stage second flotation cleaning tailings; the first-stage second flotation cleaning tailings are returned to the second rough flotation as raw materials.

[0130] Based on the feed weight, the dosage of pH regulator B in the first-stage second flotation cleaning step can be 0.2 - 0.5 kg / T; preferably 0.3 - 0.4 kg / T; more preferably 0.3 - 0.35 kg / T.

[0131] Based on the feed weight, the dosage of inhibitor B in the first-stage second flotation cleaning step is 0.2 - 0.6 kg / T; preferably 0.3 - 0.5 kg / T; more preferably 0.35 - 0.45 kg / T.

[0132] Based on the feed weight, the dosage of collector B in the first-stage second flotation cleaning step is 0.1 - 0.5 kg / T; preferably 0.2 - 0.4 kg / T. In some embodiments, the dosage is 0.3 - 0.35 kg / T.

[0133] Based on the feed weight, the dosage of frother B in the first-stage second flotation cleaning step is 0.01 - 0.15 kg / T; preferably 0.05 - 0.10 kg / T; more preferably 0.07 - 0.08 kg / T.

[0134] In the first-stage second flotation concentration step, materials can be added to the second rough flotation concentrate pulp in the order of pH regulator B, inhibitor B, collector B, and frother B.

[0135] The feeding interval time between each material is 2 - 5 min; preferably 3 - 4 min. The following formula is used to calculate the feeding interval time: t = t 1 -t 2 . t represents the feeding interval time. t 1 represents the time when the subsequent material starts to be added. t 2 represents the time when the previous material is completely added.

[0136] The concentration of the second rough flotation concentrate pulp can be 35 - 60 wt%; preferably 40 - 55 wt%; more preferably 45 - 50 wt%.

[0137] The temperature of the first-stage second flotation concentration can be 35 - 65 °C; preferably 40 - 60 °C; more preferably 50 - 55 °C.

[0138] Specifically, the second-stage second flotation concentrate to the first-stage second flotation concentration respectively includes the following steps:

[0139] Form the (j - 1)-stage second flotation concentrate pulp from the (j - 1)-stage second flotation concentrate; add pH regulator B, inhibitor B, collector B, and frother B to the (j - 1)-stage second flotation concentrate pulp for the j-stage second flotation concentration to obtain the j-stage second flotation concentrate and the j-stage second flotation tailings; the j-stage second flotation tailings are returned to the (j - 1)-stage second flotation concentration as raw materials. j is an integer greater than or equal to 2 and less than or equal to I, and the I-stage second flotation concentrate is the second flotation concentrate.

[0140] Based on the weight of the feed ore, the dosage of pH regulator B in the j-stage second flotation concentration step can be 0.05 - 0.30 kg / T; preferably 0.08 - 0.25 kg / T. In some embodiments, the dosage is 0.20 - 0.23 kg / T.

[0141] Based on the weight of the feed ore, the dosage of inhibitor B in the j-stage second flotation concentration step can be 0.08 - 0.35 kg / T; preferably 0.10 - 0.30 kg / T. In some embodiments, the dosage is 0.25 - 0.28 kg / T.

[0142] Based on the weight of the feed ore, the dosage of collector B in the j-stage second flotation concentration step can be 0.05 - 0.25 kg / T; preferably 0.08 - 0.20 kg / T. In some embodiments, the dosage of collector B is 0.15 - 0.18 kg / T.

[0143] Based on the feed weight, the dosage of frother B in the second flotation cleaning step at stage j can be 0.005 - 0.07 kg / T; preferably 0.02 - 0.06 kg / T. In some embodiments, the dosage of frother B is 0.045 - 0.05 kg / T.

[0144] In the second flotation cleaning step at stage j, materials can be added to the pulp of the first flotation cleaning concentrate at stage j - 1 in the order of pH regulator B, inhibitor B, collector B, and frother B.

[0145] The feeding interval time between each material is 2 - 5 min; preferably 3 - 4 min. The feeding interval time is calculated using the following formula: t = t 1 -t 2 . t represents the feeding interval time. t 1 represents the time when the subsequent material starts to be added. t 2 represents the time when the previous material is completely added.

[0146] The concentration of the pulp of the second flotation cleaning concentrate at stage j - 1 can be 35 - 55 wt%; preferably 40 - 50 wt%; more preferably 40 - 45 wt%.

[0147] The temperature of the second flotation cleaning at stage j can be 35 - 65 °C; preferably 40 - 60 °C; more preferably 50 - 55 °C.

[0148] Preferably, I is 3. That is, a total of three - stage second flotation cleaning is carried out.

[0149] Based on the feed weight, the dosage of pH regulator B in the second flotation cleaning step at the second stage can be 0.10 - 0.30 kg / T; preferably 0.15 - 0.25 kg / T; more preferably 0.20 - 0.23 kg / T.

[0150] Based on the feed weight, the dosage of inhibitor B in the second flotation cleaning step at the second stage can be 0.15 - 0.35 kg / T; preferably 0.20 - 0.30 kg / T. In some embodiments, the dosage of inhibitor B is 0.22 - 0.23 kg / T.

[0151] Based on the feed weight, the dosage of collector B in the second flotation cleaning step at the second stage can be 0.10 - 0.25 kg / T; preferably 0.15 - 0.20 kg / T; more preferably 0.17 - 0.18 kg / T.

[0152] Based on the feed weight, the dosage of frother B in the second flotation cleaning step at the second stage can be 0.02 - 0.06 kg / T; preferably 0.03 - 0.05 kg / T. In some embodiments, the dosage of frother B is 0.04 - 0.045 kg / T.

[0153] Based on the feed weight, the dosage of pH regulator B in the third-stage second flotation concentration step can be 0.05 - 0.30 kg / T; preferably 0.08 - 0.25 kg / T. In some embodiments, the dosage is 0.20 - 0.23 kg / T.

[0154] Based on the feed weight, the dosage of inhibitor B in the third-stage second flotation concentration step can be 0.10 - 0.35 kg / T; preferably 0.11 - 0.30 kg / T. In some embodiments, the dosage of inhibitor B is 0.25 - 0.28 kg / T.

[0155] Based on the feed weight, the dosage of collector B in the third-stage second flotation concentration step can be 0.07 - 0.25 kg / T; preferably 0.085 - 0.20 kg / T. In some embodiments, the dosage of collector B is 0.15 - 0.17 kg / T.

[0156] Based on the feed weight, the dosage of frother B in the third-stage second flotation concentration step can be 0.01 - 0.06 kg / T; preferably 0.02 - 0.05 kg / T. In some embodiments, the dosage of frother B is 0.04 - 0.05 kg / T.

[0157] In some embodiments, the following steps are further included: combining the first flotation concentrate and the second flotation concentrate to obtain a rare earth concentrate.

[0158] The rare earth grade of the rare earth concentrate is greater than or equal to 30 wt%; preferably, greater than or equal to 33 wt%; more preferably, greater than or equal to 36 wt%. The rare earth grade of the rare earth concentrate can be less than or equal to 40 wt%; preferably, the rare earth grade is less than or equal to 38 wt%.

[0159] The rare earth recovery rate can be greater than or equal to 70 wt%; preferably, greater than or equal to 74 wt%; more preferably, greater than or equal to 79 wt%. The rare earth recovery rate can be less than or equal to 85 wt%; in some embodiments, the rare earth recovery rate is less than or equal to 80 wt%.

[0160] Steps of crushing and grinding the mixed rare earth concentrate

[0161] The present invention crushes the mixed rare earth ore to obtain the crushed ore; grinds the crushed ore to obtain the ground mixed rare earth ore.

[0162] The particle size of the crushed ore is less than or equal to 5.0 mm; preferably, the particle size is less than or equal to 2.0 mm.

[0163] The mixed rare earth ore can be crushed to a particle size less than or equal to 20 mm by a jaw crusher; preferably, less than or equal to 10 mm; secondary crushing is carried out by a pair-roll crusher, and then screening is carried out by a screening machine to obtain the crushed ore.

[0164] The grinding concentration can be 50 - 75 wt%; preferably 60 - 70 wt%; more preferably 60 - 65 wt%.

[0165] The following introduces the test methods:

[0166] The monomer dissociation degree of parisite: It is tested by a Mineral Automatic Analysis System (AMICS).

[0167] The monomer dissociation degree of bastnäsite: It is tested by a Mineral Automatic Analysis System (AMICS).

[0168] The REO grade: It is tested according to the method specified in GB / T 18114.1 - 2010.

[0169] The recovery rate of rare earth: It is calculated according to the formula [(the rare earth grade of rare earth concentrate × the yield of rare earth concentrate) / the rare earth grade of mixed rare earth ore] × 100%.

[0170] The following introduces the raw materials:

[0171] pH regulator: Sodium carbonate.

[0172] Inhibitor: Sodium silicate, sodium hexametaphosphate and starch with a modulus of 2.4 - 2.6 and a mass ratio of 6:3:1.

[0173] Collector: Octyl hydroxamic acid and agricultural emulsion 601 with a mass ratio of 9:1.

[0174] Frother: Methyl isobutyl carbinol.

[0175] Example 1

[0176] The mixed rare earth ore is crushed to -10 mm by a jaw crusher; secondary crushing is carried out by a pair-roll crusher, and then screening is carried out by a screening machine to obtain the crushed ore with a particle size of -2.0 mm. The mixed rare earth ore consists of parisite, bastnäsite and gangue ore. The mass ratio of parisite to bastnäsite is 4.6:3.7. The gangue ore includes calcite, mica, feldspar and apatite. In the mixed rare earth ore, the rare earth REO grade is 3.69 wt%, and the content of calcite is 42.16 wt%.

[0177] The crushed ore is ground by a ball mill, and the overflow after classification is obtained to get the mixed rare earth ore after grinding (fineness -0.074mm accounts for 86.39wt%). The grinding concentration is 62wt%. In the mixed rare earth ore after grinding, the monomer dissociation degree of parisite is 83.66%, and the monomer dissociation degree of bastnaesite is 24.18%.

[0178] The mixed rare earth ore after grinding is subjected to rough magnetic separation to obtain rough magnetic separation concentrate and rough magnetic separation tailings. The rough magnetic separation tailings are subjected to scavenging magnetic separation to obtain scavenging magnetic separation concentrate and magnetic separation tailings. The rough magnetic separation concentrate and the scavenging magnetic separation concentrate are combined to form magnetic separation concentrate. The magnetic field intensity of rough magnetic separation is 1.2T, the feed concentration is 20wt%, and the pulse frequency is 15Hz. The magnetic field intensity of scavenging magnetic separation is 1.7T, the feed concentration is 20wt%, and the pulse frequency is 18Hz.

[0179] The magnetic separation concentrate is formed into a magnetic separation concentrate pulp with a concentration of 55wt%. At 60°C, a pH regulator, an inhibitor, a collector, and a frother are sequentially added to the magnetic separation concentrate pulp for the first rough flotation to obtain the first rough flotation concentrate and the first rough flotation tailings. The feeding interval time of the pH regulator, the inhibitor, the collector, and the frother is 3min. Based on the weight of the feed, the dosage of the pH regulator is 1.4kg / t, the dosage of the inhibitor is 2.2kg / t, the dosage of the collector is 1.2kg / t, and the dosage of the frother is 0.18kg / t.

[0180] The first rough flotation concentrate is formed into a first rough flotation concentrate pulp with a concentration of 58wt%. At 50°C, a pH regulator, an inhibitor, a collector, and a frother are sequentially added to the first rough flotation concentrate pulp for the first stage of the first rough flotation cleaning to obtain the first stage of the first rough flotation cleaning concentrate and the first stage of the first rough flotation cleaning tailings. The first stage of the first rough flotation cleaning tailings is returned to the first rough flotation process as raw material. The feeding interval time of the pH regulator, the inhibitor, the collector, and the frother is 3min. Based on the weight of the feed, the dosage of the pH regulator is 0.42kg / t, the dosage of the inhibitor is 0.66kg / t, the dosage of the collector is 0.36kg / t, and the dosage of the frother is 0.054kg / t.

[0181] Form a pulp of the first-stage first flotation concentrate with a concentration of 50 wt%. At 50 °C, sequentially add a pH regulator, an inhibitor, a collector, and a foaming agent to the pulp of the first-stage first flotation concentrate for the second-stage first flotation cleaning to obtain a second-stage first flotation concentrate and a second-stage first flotation tailing. The second-stage first flotation tailing is returned to the first-stage first flotation cleaning process as a raw material. The feeding interval times of the pH regulator, the inhibitor, the collector, and the foaming agent are 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.14 kg / t, the dosage of the inhibitor is 0.22 kg / t, the dosage of the collector is 0.12 kg / t, and the dosage of the foaming agent is 0.018 kg / t.

[0182] Form a pulp of the second-stage first flotation concentrate with a concentration of 48 wt%. At 55 °C, sequentially add a pH regulator, an inhibitor, a collector, and a foaming agent to the pulp of the second-stage first flotation concentrate for the third-stage first flotation cleaning to obtain a third-stage first flotation concentrate and a third-stage first flotation tailing. The third-stage first flotation tailing is returned to the second-stage first flotation cleaning process as a raw material. The third-stage first flotation concentrate is used as the first flotation concentrate. The feeding interval times of the pH regulator, the inhibitor, the collector, and the foaming agent are 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.14 kg / t, the dosage of the inhibitor is 0.22 kg / t, the dosage of the collector is 0.12 kg / t, and the dosage of the foaming agent is 0.018 kg / t.

[0183] Fine-grind the first flotation tailing with an Isa mill, and overflow after classification to obtain the first flotation tailing after grinding (the fineness of -0.03 mm accounts for 93.15 wt%). The grinding concentration is 60 wt%. In the first flotation tailing after grinding, the monomer dissociation degree of bastnaesite is 82%.

[0184] Form a pulp of the first flotation tailing after grinding with a concentration of 45 wt%. At 60 °C, sequentially add a pH regulator, an inhibitor, a collector, and a foaming agent to the pulp of the first flotation tailing after grinding for the second flotation roughing to obtain a second flotation roughing concentrate and a second flotation tailing. The feeding interval times of the pH regulator, the inhibitor, the collector, and the foaming agent are 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.8 kg / t, the dosage of the inhibitor is 1.1 kg / t, the dosage of the collector is 0.85 kg / t, and the dosage of the foaming agent is 0.2 kg / t.

[0185] The second rough flotation concentrate is formed into a second rough flotation concentrate pulp with a concentration of 45 wt%. At 50 °C, a pH regulator, an inhibitor, a collector, and a frother are sequentially added to the second rough flotation concentrate pulp for the first-stage second flotation cleaning to obtain a first-stage second flotation cleaning concentrate and a first-stage second flotation cleaning tailings. The first-stage second flotation cleaning tailings are returned to the second rough flotation process as raw materials. The feeding interval times of the pH regulator, the inhibitor, the collector, and the frother are 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.32 kg / t, the dosage of the inhibitor is 0.44 kg / t, the dosage of the collector is 0.34 kg / t, and the dosage of the frother is 0.08 kg / t.

[0186] The first-stage second flotation cleaning concentrate is formed into a first-stage second flotation cleaning concentrate pulp with a concentration of 42 wt%. At 50 °C, a pH regulator, an inhibitor, a collector, and a frother are sequentially added to the first-stage second flotation cleaning concentrate pulp for the second-stage second flotation cleaning to obtain a second-stage second flotation cleaning concentrate and a second-stage second flotation cleaning tailings. The second-stage second flotation cleaning tailings are returned to the first-stage second flotation cleaning process as raw materials. The feeding interval times of the pH regulator, the inhibitor, the collector, and the frother are 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.16 kg / t, the dosage of the inhibitor is 0.22 kg / t, the dosage of the collector is 0.17 kg / t, and the dosage of the frother is 0.04 kg / t.

[0187] The second-stage second flotation cleaning concentrate is formed into a second-stage second flotation cleaning concentrate pulp with a concentration of 40 wt%. At 50 °C, a pH regulator, an inhibitor, a collector, and a frother are sequentially added to the second-stage second flotation cleaning concentrate pulp for the third-stage second flotation cleaning to obtain a third-stage second flotation cleaning concentrate and a third-stage second flotation cleaning tailings. The third-stage second flotation cleaning tailings are returned to the second-stage second flotation cleaning process as raw materials. The third-stage second flotation cleaning concentrate is used as the second flotation concentrate. The feeding interval times of the pH regulator, the inhibitor, the collector, and the frother are 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.08 kg / t, the dosage of the inhibitor is 0.11 kg / t, the dosage of the collector is 0.085 kg / t, and the dosage of the frother is 0.02 kg / t.

[0188] The first flotation concentrate and the second flotation concentrate are combined as the rare earth concentrate. The magnetic separation tailings and the second flotation tailings are combined as the tailings.

[0189] The grade of rare earth REO in the rare earth concentrate is 36.55 wt%, and the recovery rate of rare earth is 74.28 wt%.

[0190] Example 2

[0191] The mixed rare earth ore is crushed to -10 mm using a jaw crusher; it is secondarily crushed using a pair-roll crusher and then screened using a screening machine to obtain the crushed ore with a particle size of -2.0 mm. The mixed rare earth ore consists of parisite, bastnäsite and gangue ore. The mass ratio of parisite to bastnäsite is 5.5:4.5. The gangue ore includes calcite, mica, feldspar and apatite. In the mixed rare earth ore, the grade of rare earth REO is 4.14 wt%, and the content of calcite is 45.88 wt%.

[0192] The crushed ore is ground using a ball mill, and the overflow after classification is obtained to get the ground mixed rare earth ore (the fineness of -0.074 mm accounts for 89.56 wt%). The grinding concentration is 65 wt%. In the ground mixed rare earth ore, the monomer dissociation degree of parisite is 87.52%, and the monomer dissociation degree of bastnäsite is 27.15%.

[0193] The ground mixed rare earth ore is subjected to rough magnetic separation to obtain the rough magnetic separation concentrate and the rough magnetic separation tailings. The rough magnetic separation tailings are subjected to scavenging magnetic separation to obtain the scavenging magnetic separation concentrate and the magnetic separation tailings. The rough magnetic separation concentrate and the scavenging magnetic separation concentrate are combined to form the magnetic separation concentrate. The magnetic field intensity of the rough magnetic separation is 1.4 T, the feed concentration is 20 wt%, and the pulse frequency is 13 Hz. The magnetic field intensity of the scavenging magnetic separation is 1.8 T, the feed concentration is 20 wt%, and the pulse frequency is 15 Hz.

[0194] The magnetic separation concentrate is formed into a magnetic separation concentrate pulp with a concentration of 55 wt%; at 60 °C, a pH regulator, an inhibitor, a collector and a foaming agent are sequentially added to the magnetic separation concentrate pulp for the first rough flotation to obtain the first rough flotation concentrate and the first rough flotation tailings. The feeding interval time of the pH regulator, the inhibitor, the collector and the foaming agent is 3 min. Based on the weight of the feed, the dosage of the pH regulator is 1.4 kg / t, the dosage of the inhibitor is 2.2 kg / t, the dosage of the collector is 1.2 kg / t, and the dosage of the foaming agent is 0.18 kg / t.

[0195] The first rough flotation concentrate is formed into a first rough flotation concentrate pulp with a concentration of 55 wt%; at 55 °C, a pH regulator, an inhibitor, a collector and a foaming agent are sequentially added to the first rough flotation concentrate pulp for the first stage of the first rough flotation cleaning to obtain the first stage of the first rough flotation cleaning concentrate and the first stage of the first rough flotation cleaning tailings. The first stage of the first rough flotation cleaning tailings is returned to the first rough flotation process as raw material. The feeding interval time of the pH regulator, the inhibitor, the collector and the foaming agent is 3 min. Based on the weight of the feed, the dosage of the pH regulator is 0.42 kg / t, the dosage of the inhibitor is 0.66 kg / t, the dosage of the collector is 0.36 kg / t, and the dosage of the foaming agent is 0.054 kg / t.

[0196] The first-stage first flotation concentrate is formed into a first-stage first flotation concentrate pulp with a concentration of 48 wt%. At 50 °C, a pH regulator, an inhibitor, a collector, and a foaming agent are sequentially added to the first-stage first flotation concentrate pulp for the second-stage first flotation cleaning to obtain a second-stage first flotation concentrate and a second-stage first flotation tailing. The second-stage first flotation tailing is returned to the first-stage first flotation cleaning process as a raw material. The feeding interval time of the pH regulator, the inhibitor, the collector, and the foaming agent is 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.14 kg / t, the dosage of the inhibitor is 0.22 kg / t, the dosage of the collector is 0.12 kg / t, and the dosage of the foaming agent is 0.018 kg / t.

[0197] The second-stage first flotation concentrate is formed into a second-stage first flotation concentrate pulp with a concentration of 45 wt%. At 50 °C, a pH regulator, an inhibitor, a collector, and a foaming agent are sequentially added to the second-stage first flotation concentrate pulp for the third-stage first flotation cleaning to obtain a third-stage first flotation concentrate and a third-stage first flotation tailing. The third-stage first flotation tailing is returned to the second-stage first flotation cleaning process as a raw material. The third-stage first flotation concentrate is used as the first flotation concentrate. The feeding interval time of the pH regulator, the inhibitor, the collector, and the foaming agent is 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.14 kg / t, the dosage of the inhibitor is 0.22 kg / t, the dosage of the collector is 0.12 kg / t, and the dosage of the foaming agent is 0.018 kg / t.

[0198] The first flotation tailing is finely ground by an Isa mill, and the overflow after classification is obtained as the first flotation tailing after grinding (the fineness of -0.03 mm accounts for 90.44 wt%). The grinding concentration is 55 wt%. In the first flotation tailing after grinding, the monomer dissociation degree of bastnaesite is 78%.

[0199] The first flotation tailing after grinding is formed into a first flotation tailing pulp after grinding with a concentration of 50 wt%. At 65 °C, a pH regulator, an inhibitor, a collector, and a foaming agent are sequentially added to the first flotation tailing pulp after grinding for the second flotation roughing to obtain a second flotation roughing concentrate and a second flotation tailing. The feeding interval time of the pH regulator, the inhibitor, the collector, and the foaming agent is 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 1.1 kg / t, the dosage of the inhibitor is 1.3 kg / t, the dosage of the collector is 0.75 kg / t, and the dosage of the foaming agent is 0.25 kg / t.

[0200] The second roughing concentrate is formed into a second roughing concentrate pulp with a concentration of 48 wt%. At 55 °C, a pH regulator, an inhibitor, a collector, and a foaming agent are sequentially added to the second roughing concentrate pulp for the first-stage second cleaning flotation to obtain a first-stage second cleaning flotation concentrate and a first-stage second cleaning flotation tailing. The first-stage second cleaning flotation tailing is returned to the second roughing process as raw material. The feeding interval time of the pH regulator, the inhibitor, the collector, and the foaming agent is 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.33 kg / t, the dosage of the inhibitor is 0.39 kg / t, the dosage of the collector is 0.225 kg / t, and the dosage of the foaming agent is 0.075 kg / t.

[0201] The first-stage second cleaning flotation concentrate is formed into a first-stage second cleaning flotation concentrate pulp with a concentration of 45 wt%. At 52 °C, a pH regulator, an inhibitor, a collector, and a foaming agent are sequentially added to the first-stage second cleaning flotation concentrate pulp for the second-stage second cleaning flotation to obtain a second-stage second cleaning flotation concentrate and a second-stage second cleaning flotation tailing. The second-stage second cleaning flotation tailing is returned to the first-stage second cleaning flotation process as raw material. The feeding interval time of the pH regulator, the inhibitor, the collector, and the foaming agent is 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.22 kg / t, the dosage of the inhibitor is 0.26 kg / t, the dosage of the collector is 0.15 kg / t, and the dosage of the foaming agent is 0.05 kg / t.

[0202] The second-stage second cleaning flotation concentrate is formed into a second-stage second cleaning flotation concentrate pulp with a concentration of 42 wt%. At 50 °C, a pH regulator, an inhibitor, a collector, and a foaming agent are sequentially added to the second-stage second cleaning flotation concentrate pulp for the third-stage second cleaning flotation to obtain a third-stage second cleaning flotation concentrate and a third-stage second cleaning flotation tailing. The third-stage second cleaning flotation tailing is returned to the second-stage second cleaning flotation process as raw material. The third-stage second cleaning flotation concentrate is used as the second cleaning flotation concentrate. The feeding interval time of the pH regulator, the inhibitor, the collector, and the foaming agent is 3 min. Based on the weight of the feed ore, the dosage of the pH regulator is 0.22 kg / t, the dosage of the inhibitor is 0.26 kg / t, the dosage of the collector is 0.15 kg / t, and the dosage of the foaming agent is 0.05 kg / t.

[0203] The first cleaning flotation concentrate and the second cleaning flotation concentrate are combined as the rare earth concentrate. The magnetic separation tailing and the second cleaning flotation tailing are combined as the tailing.

[0204] The grade of rare earth REO in the rare earth concentrate is 33.82 wt%, and the recovery rate of rare earth is 79.51 wt%.

[0205] The present invention is not limited to the above embodiments, and any variations, improvements, or substitutions that can be conceived by those skilled in the art without departing from the essence of the present invention fall within the scope of the present invention.

Claims

1. A method for beneficiating a mixed rare earth ore, characterized in that: The steps include: (1) subjecting the ground mixed rare earth ore to magnetic separation to obtain magnetic separation concentrate and magnetic separation tailings; wherein the mixed rare earth ore contains cerium nitrate and cerium fluoride; (2) subjecting the magnetic separation concentrate to first flotation in the presence of pH regulator A, inhibitor A, collector A and frother A to obtain a first flotation concentrate and a first flotation tailings; Wherein, the inhibitor A comprises water glass, phosphate and starch in a mass ratio of (4-8): (1-5): (0.5-3), the collector A comprises C5-C10 hydroxamic acid and styrylphenol polyoxyethylene ether in a mass ratio of (7-11): (0.5-3), and the foaming agent A is a fatty alcohol foaming agent; (3) grinding the first flotation tailings to obtain ground first flotation tailings; (4) subjecting the first flotation tailings after grinding to a second flotation in the presence of a pH regulator B, an inhibitor B, a collector B and a frother B to obtain a second flotation concentrate and a second flotation tailings; Wherein, the inhibitor B comprises water glass, phosphate and starch in a mass ratio of (4-8): (1-5): (0.5-3), the collector B comprises C5-C10 hydroxamic acid and styrylphenol polyoxyethylene ether in a mass ratio of (7-11): (0.5-3), and the foaming agent B is a fatty alcohol foaming agent.

2. The ore dressing method according to claim 1, characterized in that: Step (1) includes the following steps: The mixed rare earth ore after grinding is subjected to magnetic roughing to obtain magnetic roughing concentrate and magnetic roughing tailings; wherein the magnetic roughing field strength is 1.1-1.5T, the feed concentration is 10-30wt%, and the pulse frequency is 12-16Hz; The magnetic rougher tailings are subjected to magnetic scavenging to obtain magnetic scavenging concentrate and magnetic tailings; wherein the magnetic scavenging field strength is 1.6-2.0T, the feed concentration is 10-30wt%, and the pulse frequency is 13-20Hz; Combining the magnetic rougher concentrate and the magnetic scavenger concentrate to obtain a magnetic concentrate; The fineness of the mixed rare earth ore after grinding is below 0.074 mm, accounting for 75-100wt%.

3. The ore dressing method according to claim 1, characterized in that: The modulus of the water glass is 2 to 3, the phosphate is selected from one or more of sodium hexametaphosphate and trisodium phosphate, the hydroxamic acid is C7 to C9 hydroxamic acid, the styrylphenol polyoxyethylene ether is selected from one or more of Nong Ru 601, Nong Ru 602, Nong Ru 603, and Nong Ru 604, the fatty alcohol foaming agent is an aliphatic monohydric alcohol containing C4 to C10, the pH adjuster A is a carbonate, and the pH adjuster B is a carbonate.

4. The ore dressing method according to claim 1, characterized in that: Step (2) includes the following steps: The magnetic concentrate is formed into a magnetic concentrate pulp with a concentration of 45-65wt%; at 50-70°C, a pH regulator A, an inhibitor A, a collector A and a frother A are added to the magnetic concentrate pulp for a first flotation roughing to obtain a first flotation roughing concentrate and a first flotation tailing; wherein, based on the weight of the feed ore, the amount of the pH regulator is 1.0-2.0kg / T, the amount of the inhibitor is 1.5-2.5kg / T, the amount of the collector is 0.9-1.5kg / T, and the amount of the frother is 0.1-0.3kg / T; The first flotation rougher concentrate is subjected to N-stage first flotation cleaning to obtain a first flotation concentrate, wherein N is an integer greater than or equal to 2; The first flotation concentration comprises the following steps: forming a first flotation roughing concentrate slurry from the first flotation roughing concentrate; adding pH regulator A, inhibitor A, collector A and frother A to the first flotation roughing concentrate slurry for first flotation concentration to obtain a first flotation concentrate and a first flotation tailings; returning the first flotation tailings to the first flotation roughing as a raw material; based on the weight of the feed ore, the amount of pH regulator A is 0.2-0.6 kg / T, the amount of inhibitor A is 0.4-0.9 kg / T, the amount of collector A is 0.1-0.5 kg / T, and the amount of frother A is 0.01-0.2 kg / T; Among them, the second-level first flotation cleaning to the N-level first flotation cleaning respectively include the following steps: The m-1-level first flotation concentrate is formed into an m-1-level first flotation concentrate slurry; pH ​​regulator A, inhibitor A, collector A and frother A are added to the m-1-level first flotation concentrate slurry to carry out m-level first flotation concentration to obtain m-level first flotation concentrate and m-level first flotation concentration tailings; the m-level first flotation concentration tailings are returned to the m-1-level first flotation concentration as a raw material; based on the weight of the feed ore, the amount of pH regulator A is 0.05-0.25 kg / T, the amount of inhibitor A is 0.10-0.35 kg / T, the amount of collector A is 0.05-0.25 kg / T, and the amount of frother A is 0.005-0.035 kg / T; wherein m is an integer greater than or equal to 2 and less than or equal to N, and the N-level first flotation concentrate is the first flotation concentrate.

5. The ore dressing method according to claim 4, characterized in that: In step (2), pH regulator A, inhibitor A, collector A and frother A are added in the order of each material, and the interval between each material addition is 2 to 5 minutes; Among them, the feeding interval time is calculated using the following formula: t=t1-t2; Among them, t represents the feeding interval time, t1 represents the time when the next material starts to be added, and t2 represents the time when the previous material is finished adding.

6. The ore dressing method according to claim 1, characterized in that: In step (3), the grinding concentration is 50-65wt%, and the fineness of the first flotation tailings after grinding is 85-100wt% of that below 0.03mm.

7. The ore dressing method according to claim 1, characterized in that: Step (4) includes the following steps: The first flotation tailings after grinding are formed into a first flotation tailings slurry with a concentration of 40-65wt%; pH regulator B, inhibitor B, collector B and frother B are added to the first flotation tailings slurry at 50-70°C to perform a second flotation roughing to obtain a second flotation roughing concentrate and a second flotation tailings; wherein, based on the weight of the feed ore, the amount of pH regulator B is 0.6-1.3kg / T, the amount of inhibitor B is 0.8-1.6kg / T, the amount of collector B is 0.5-1.1kg / T, and the amount of frother B is 0.1-0.5 kg / T; The second flotation rougher concentrate is subjected to a second flotation concentration of level I to obtain a second flotation concentrate; I is an integer greater than or equal to 2; Among them, the first-level second flotation concentration includes the following steps: The second flotation roughing concentrate is formed into a second flotation roughing concentrate slurry; pH ​​regulator B, inhibitor B, collector B and frother B are added to the second flotation roughing concentrate slurry to carry out a first-stage second flotation concentration to obtain a first-stage second flotation concentration concentrate and a first-stage second flotation concentration tailings; the first-stage second flotation concentration tailings are returned to the second flotation roughing as a raw material; based on the weight of the feed ore, the amount of pH regulator B is 0.2-0.5 kg / T, the amount of inhibitor B is 0.2-0.6 kg / T, the amount of collector B is 0.1-0.5 kg / T, and the amount of frother B is 0.01-0.15 kg / T; Among them, the second level flotation cleaning to the first level flotation cleaning respectively include the following steps: The j-1-level second flotation concentrate is formed into a j-1-level second flotation concentrate slurry; pH ​​regulator B, inhibitor B, collector B and frother B are added to the j-1-level second flotation concentrate slurry to perform j-level second flotation concentration to obtain j-level second flotation concentrate and j-level second flotation concentration tailings; the j-level second flotation concentration tailings are returned to the j-1-level second flotation concentration as a raw material; based on the feed weight, the amount of pH regulator B is 0.05-0.30kg / T, the amount of inhibitor B is 0.08-0.35kg / T, the amount of collector B is 0.05-0.25kg / T, and the amount of frother B is 0.005-0.07kg / T; wherein j is an integer greater than or equal to 2 and less than or equal to 1, and the I-level second flotation concentration is the second flotation concentrate.

8. The ore dressing method according to claim 7, characterized in that: In step (4), pH regulator B, inhibitor B, collector B and frother B are added in the order of addition, and the interval between the addition of each material is 2 to 5 minutes; Among them, the feeding interval time is calculated using the following formula: t=t1-t2; Among them, t represents the feeding interval time, t1 represents the time when the next material starts to be added, and t2 represents the time when the previous material is finished adding.

9. The ore dressing method according to claim 1, characterized in that: The steps include: The first flotation concentrate and the second flotation concentrate are combined to obtain a rare earth concentrate.

10. The ore dressing method according to claim 1, characterized in that: The following steps are also included: crushing the mixed rare earth ore to obtain crushed ore; grinding the crushed ore to obtain ground mixed rare earth ore; The mass ratio of sodium cerium ore to fluorite in the mixed rare earth ore is (3-6.5): (2-5.5), and the mixed rare earth ore also contains at least one of calcite, mica, feldspar and apatite.