A process for efficiently separating bastnasite and monazite from mixed rare earth concentrates

Abstract

The present invention discloses a process for efficiently separating bastnasite and monazite from mixed rare earth concentrates, comprising the following steps: S1: The ore sample is subjected to primary centrifugal gravity separation for roughing. The gravity separation concentrate is finely ground, and after grinding, the gravity separation concentrate and the gravity separation tailings are mixed and then enter the flotation operation; S2: Water is added to adjust the pulp concentration and pH value, a sulfate composite inhibitor is added, a hydroxamic acid composite collector is added, and octanoic acid is added as a foaming agent for roughing to obtain a bastnasite roughing concentrate and a bastnasite roughing tailings; S3: The pH value of the bastnasite roughing concentrate pulp is adjusted, the same composite inhibitor and collector as those in the roughing are added, and two-stage cleaning is carried out to obtain a bastnasite concentrate; S4: The roughing tailings are finely ground, and scavenging is carried out after grinding; the pH value of the bastnasite roughing concentrate pulp is adjusted, the same composite inhibitor and collector as those in the roughing are added, and one-stage scavenging is carried out to obtain a monazite concentrate. The process of the present invention is simple and has less reagent consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of rare earth ore dressing, and particularly relates to a process for efficiently separating bastnasite and monazite from mixed rare earth concentrate. Background Art

[0002] China is rich in rare earth resources, and the mixed rare earth resources mainly consist of bastnasite and monazite. Such mixed rare earth resources are concentrated by ore dressing to obtain mixed rare earth concentrate. Different ore dressing processes result in different grades of rare earth concentrate, but compared with the original ore, the ratio of bastnasite to monazite does not change significantly.

[0003] There are many types of rare earth minerals in Bayan Obo, but more than 90% of the rare earth elements are concentrated in two minerals, bastnasite and monazite, and their ratio is 3:1, both reaching the rare earth recovery grade. Therefore, if the mixed rare earth in Bayan Obo can be efficiently separated from the source to obtain high-purity bastnasite concentrate and monazite concentrate, they can be smelted separately.

[0004] Patent: A beneficiation method for separating bastnasite and monazite from high-grade mixed rare earth concentrate, patent number CN102886312A. In the present invention, the high-grade mixed rare earth concentrate is calcined at a temperature of 480 - 650°C, and a fractional beneficiation method of one rough selection, two fine selections, and three scavenging selections is used to perform flotation separation of bastnasite and monazite on the calcined ore. Finally, bastnasite concentrate with a recovery rate greater than 95% and a purity greater than 98% is obtained, as well as monazite concentrate with a recovery rate and a purity both greater than 90%. Although this method has high separation efficiency, it needs to be calcined first, which will destroy the continuity of the ore dressing process in actual production. Secondly, directly calcining the mixed ore will also have a very adverse impact from the perspective of low-carbon environmental protection.

[0005] Patent: A method for flotation separation of monazite and bastnasite from mixed rare earth concentrate, patent number CN101474597A. This process flow is complex and requires separate water washing. Through grinding - screening - separation rough selection, the rough concentrate of bastnasite and the rough concentrate of monazite obtained by one rough selection of bastnasite and one rough selection of monazite respectively undergo two fine selection flotation operations, and high-grade single monazite concentrate and single bastnasite concentrate can be produced. For fine particle sizes, it is difficult to use fine screen classification, and this process does not require the purity of the produced bastnasite concentrate and monazite concentrate.

[0006] Chemical separation method of bastnaesite and monazite in patent mixed rare earth concentrate, Patent CN102051477A. The present invention separates single bastnaesite concentrate and monazite concentrate from Baotou mixed rare earth concentrate (mixed rare earth minerals of bastnaesite and monazite), and uses a complexation method to make fluoride ions form complexes and enter the solution to destroy bastnaesite. Using this process, the mineral decomposition time is long, and Bayan Obo ore has the characteristics of dispersion of rare earth, thorium, and fluorine. Therefore, the chemical method has disadvantages such as low rare earth recovery rate and unsafe operation. Summary of the Invention

[0007] The purpose of the present invention is to provide a process for efficiently separating bastnaesite and monazite from mixed rare earth concentrate, so as to separate the bastnaesite and monazite in the mixed rare earth concentrate by ore dressing. This method has a simple process, low reagent consumption, and can obtain single bastnaesite concentrate and monazite concentrate with high grade, high purity, and high recovery rate, solving the problems of complex process and low separation efficiency in the previous process of treating mixed rare earth concentrate to separate bastnaesite concentrate and monazite concentrate.

[0008] To solve the above technical problems, the present invention adopts the following technical solutions:

[0009] A process for efficiently separating bastnaesite and monazite from mixed rare earth concentrate of the present invention includes the following steps:

[0010] S1: The ore sample is subjected to primary centrifugal gravity separation for rough selection, the gravity separation concentrate is finely ground, and the ground gravity separation concentrate and the gravity separation tailings are mixed and then enter the flotation operation;

[0011] S2: Add water to adjust the pulp concentration and pH value, add a sulfate composite inhibitor, add a hydroxamic acid composite collector, add octanoic acid as a foaming agent, and perform rough selection to obtain the rough selection concentrate of bastnaesite and the rough selection tailings of bastnaesite;

[0012] S3: Adjust the pH value of the pulp of the rough selection concentrate of bastnaesite, add the same composite inhibitor and collector as in the rough selection, and perform two-stage cleaning to obtain bastnaesite concentrate;

[0013] S4: The rough selection tailings are finely ground, and then scavenging is performed after grinding; adjust the pH value of the pulp of the rough selection concentrate of bastnaesite, add the same composite inhibitor and collector as in the rough selection, and perform one-stage scavenging to obtain monazite concentrate.

[0014] Furthermore, the middlings from the secondary cleaning of the rough selection concentrate of bastnaesite and the scavenging of the rough selection tailings of bastnaesite are combined and returned to the rough selection operation.

[0015] Furthermore, in the composite inhibitor, the dosage ratio of aluminum sulfate / sulfuric acid zinc is (10:1 - 20:1), and the total dosage of the composite inhibitor is: 8.0 - 11.6 Kg / T for rough selection, and 4.0 - 5.3 Kg / T for cleaning.

[0016] Furthermore, in the composite collector, the dosage ratio of phthalic acid, N-hydroxyphthalimide ammonium, and o-carboxybenzohydroxamic acid is (5:2:1 - 7:3:1), and the total dosage of the composite collector is: 5.0 - 6.67 Kg / T for roughing, 4.0 - 6.0 Kg / T for cleaning, and 1.5 - 2.0 Kg / T for scavenging.

[0017] Furthermore, the total dosage of the foaming agent octanoic acid is: 1.5 - 2.0 Kg / T for roughing, 6.0 - 8.5 Kg / T for cleaning.

[0018] Furthermore, the centrifugal gravity separation equipment in step S1 is a Nelson concentrator. The content of the gravity separation concentrate with -500 mesh is 60% - 65%, the content with -5um is less than 1.0%, the content of the tailings with -500 mesh is greater than 90%, and the content with -5um is greater than 8%.

[0019] Furthermore, the fine grinder in step S1 is an Isa mill. After grinding and mixing with the gravity separation tailings, the particle size of the ore sample is 88% - 93% with -500 mesh, and the content with -5um is less than 15%.

[0020] Furthermore, during the roughing, cleaning, and scavenging processes in steps S2, S3, and S4, the PH is 4.0 - 5.0, and the concentration is 60% - 70%.

[0021] Furthermore, the action time of the composite inhibitor is 2 - 3 min, the action time of the collector is 3 - 5 min, and the action time of the foaming agent is 1 - 2 min.

[0022] Furthermore, the flotation time: the roughing time is 7 - 10 min, the scavenging time is 3 - 5 min, and the cleaning time is 3 - 5 min.

[0023] Compared with the prior art, the beneficial technical effects of the present invention are:

[0024] 1) By adopting this process flow, it is possible to obtain bastnaesite concentrate and monazite concentrate products with high grade, high purity, and high recovery rate through a conventional flotation process, without the need to increase the difference between bastnaesite ore and monazite ore by roasting, that is, high-grade, high-recovery-rate, and high-purity bastnaesite concentrate and monazite concentrate can be obtained.

[0025] 2) This process solves the problem of fine-grained screening. Using gravity separation to replace the conventional screening process can effectively improve the fine-grained screening efficiency and obtain a higher recovery rate than the conventional flotation process.

[0026] 3) The agents used in this process solve the problem of separating fine-grained minerals, making the fine-grained flotation more stable and the product indicators better. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] Figure 1 It is a closed-circuit process flow diagram for the separation of rare earths from a mixed rare earth ore. Specific embodiments

[0029] Example 1:

[0030] Using 65.18% rare earth mixed concentrate as raw material, it is determined that the bastnaesite ReO in this raw material is 41.06%, and the monazite ReO is 24.12%. Using the process technology of the present invention, the separation of bastnaesite and monazite is carried out. The specific steps are as Figure 1 shown:

[0031] 1) Gravity separation: Weigh 700 g of high-grade mixed concentrate and add it to a Nelson concentrator, with a feed concentration of 55%. After gravity separation, the concentrate yield is measured to be 37%, and the tailing yield is 63%. In the concentrate, -28um accounts for 83.57%, and -5um accounts for 5.25%; in the tailings, -28um accounts for 98.35%, and -5um accounts for 30.5%.

[0032] 2) Grinding: Weigh 500 g of gravity separation concentrate and add it to an IsaMill for fine grinding. The final grinding fineness is -28um accounting for 92.8%, and -5um accounting for 13.05%. Mix the product after grinding with the gravity separation tailings, and transfer the pulp raw material to a flotation cell, adjusting the pulp to a concentration of 65%.

[0033] 3) During flotation, adjust the pulp pH value to 5.0, add 10.0 kg / t of a composite inhibitor (the dosage ratio of aluminum sulfate salt to zinc sulfate is 15:1), and let it act for 2 minutes. Then add 4.6 kg / t of a composite collector (the dosage ratio of phthalic acid, N-hydroxyphthalimide ammonium, and o-carboxybenzohydroxamic acid is 5:2:1), and let it act for 3 minutes. Then add 1.5 kg / t of octanoic acid foaming agent and let it act for 1 minute to carry out the rough selection of bastnaesite. The rough selection time is 10 minutes to obtain the rough selection concentrate of bastnaesite and the rough selection tailings of bastnaesite.

[0034] 4) Adjust the pH value of the rough selection tailings of bastnaesite to 5.0, add 2.0 kg / t of a composite collector (the dosage ratio of phthalic acid, N-hydroxyphthalimide ammonium, and o-carboxybenzohydroxamic acid is 5:2:1), and let it act for 2 minutes to carry out one scavenging. The scavenging time is 3 minutes to obtain the scavenging concentrate.

[0035] 5) Adjust the pH value of the bastnasite rough concentrate to 6.0, add 4.5 kg / t of a composite inhibitor (the dosage ratio of aluminum sulfate salt to zinc sulfate is 15:1), and let it act for 3 minutes. Then add 5.2 kg / t of a composite collector (the dosage ratio of phthalic acid, N-hydroxyphthalimide ammonium, and o-carboxybenzohydroxamic acid is 5:2:1), and let it act for 4 minutes. Then add 6.0 kg / t of octanoic acid foaming agent and let it act for 1 minute. Conduct two rounds of cleaning. No medicine is added in the second round of cleaning. Each round of cleaning takes 4 minutes to obtain the bastnasite concentrate.

[0036] 6) The middlings in the above steps 4) and 5) are both returned to step 3) to form a closed-circuit process, and the bastnasite concentrate and monazite concentrate are obtained respectively.

[0037] 7) The grade of the rare earth fluoride carbonate concentrate finally obtained by this separation process is 66.64% ReO, and the operating recovery rate of ReO is 92.76%; the relative purity of rare earth fluoride carbonate F-ReO / ReO is 95.25%. The grade of the monazite concentrate is 53.46% ReO, the purity is 90.51%, the operating recovery rate is 93.66%, and the flotation indexes are higher than those of the existing flotation processes.

[0038] Example 2:

[0039] Using 66.35% rare earth mixed concentrate as the raw material, it is measured that the ReO of bastnasite in this raw material is 46.92%, and the ReO of monazite is 20.79%. Using the process technology of the present invention, separate the bastnasite and monazite, and the specific steps are as Figure 1 shown:

[0040] 1) Gravity separation: Weigh 700 g of high-grade mixed concentrate and add it to a Knelson concentrator, with a feed concentration of 50%. After gravity separation, it is measured that the concentrate yield is 32%, the tailing yield is 68%, the proportion of -28um in the concentrate is 85.12%, and the proportion of -5um is 4.48%; the proportion of -28um in the tailings is 98.26%, and the proportion of -5um is 32.6%.

[0041] 2) Grinding: Weigh 500 g of the gravity separation concentrate and add it to an Aisha mill for fine grinding. The final grinding fineness is that the proportion of -28um is 93.7%, and the proportion of -5um is 12.04%. Mix the product after grinding with the gravity separation tailings, and transfer the pulp raw material to a flotation cell, and adjust the pulp to a concentration of 60%.

[0042] 3) During the flotation process, adjust the pulp pH value to 4.0, add 10.0 kg / t of the composite inhibitor (the dosage ratio of aluminum sulfate salt to zinc sulfate is 8.5:1), act for 3 minutes, then add 6.0 kg / t of the composite collector (the dosage ratio of phthalic acid, N-hydroxyphthalimide ammonium, and o-carboxybenzohydroxamic acid is 7:2:1), act for 5 minutes, then add 1.8 kg / t of octanoic acid foaming agent, act for 2 minutes, and conduct the rough selection of bastnasite. The rough selection time is 8 minutes to obtain the rough-selected concentrate of bastnasite and the rough-selected tailings of bastnasite.

[0043] 4) Adjust the pH value of the rough-selected tailings of bastnasite to 4.0, add 1.5 kg / t of the composite collector (the dosage ratio of phthalic acid, N-hydroxyphthalimide ammonium, and o-carboxybenzohydroxamic acid is 7:2:1), act for 4 minutes, conduct one scavenging, and the scavenging time is 3 minutes to obtain the scavenged concentrate.

[0044] 5) Adjust the pH value of the rough-selected concentrate of bastnasite to 4.0, add 4.0 kg / t of the composite inhibitor (the dosage ratio of aluminum sulfate salt to zinc sulfate is 15:1), act for 3 minutes, then add 5.0 kg / t of the composite collector (the dosage ratio of phthalic acid, N-hydroxyphthalimide ammonium, and o-carboxybenzohydroxamic acid is 7:2:1), act for 4 minutes, then add 6.0 kg / t of octanoic acid foaming agent, act for 1 minute, conduct two cleaning operations, without adding medicine in the second cleaning operation, and the cleaning time for each time is 3 minutes to obtain the bastnasite concentrate.

[0045] 6) The middlings in the above steps 4) and 5) are both returned to step 3) to form a closed-circuit flow, and then the bastnasite concentrate and the monazite concentrate are obtained respectively.

[0046] 7) The grade of the rare earth fluoride carbonate concentrate finally obtained by this separation process is 67.02% for ReO, and the operating recovery rate is 91.72% for ReO; the relative purity of the rare earth fluoride carbonate is 95.56% for F-ReO / ReO. The grade of the monazite concentrate is 53.92% for ReO, the purity is 90.62%, and the operating recovery rate is 92.83%.

[0047] This application has at least the following technical effects or advantages:

[0048] 1) Solved the problem of directly flotation separation of high-purity bastnasite concentrate and monazite concentrate from the Bayan Obo mixed rare earth ore.

[0049] 2) Effectively solved the problem of particle size classification of fine-grained minerals, improved the classification efficiency, and avoided over-grinding at the same time.

[0050] 3) It effectively solves the problems of high metal loss rate and low recovery rate during the separation process. This process has the characteristics of low cost, high separation efficiency, short and easy-to-stabilize operation, high purity of bastnaesite concentrate and monazite concentrate, and high recovery rate. The beneficiation reagents have strong adaptability to fine-grained minerals and do not have common problems such as instability, large fluctuations, and difficult control in conventional flotation.

[0051] The embodiments described above are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A process for efficiently separating bastnasite and monazite from mixed rare earth concentrates, characterized in that, It includes the following steps: S1: The ore sample undergoes primary centrifugal gravity separation for roughing. The gravity separation concentrate is finely ground. After grinding, the gravity separation concentrate and the gravity separation tailings are mixed and then enter the flotation operation; S2: Add water to adjust the pulp concentration and pH value, add a composite inhibitor of sulfate salts, add a composite collector of hydroxamic acids, add octanoic acid as a foaming agent, and conduct roughing to obtain a rough concentrate of bastnaesite and a rough tailings of bastnaesite; S3: Adjust the pH value of the bastnaesite rough concentrate pulp, add the same composite inhibitor and collector as in the roughing, and conduct two-stage cleaning to obtain a bastnaesite concentrate; S4: The rough tailings are finely ground, and then scavenging is carried out after grinding; adjust the pH value of the bastnaesite rough concentrate pulp, add the same composite inhibitor and collector as in the roughing, and conduct one-stage scavenging to obtain a monazite concentrate; In the said composite inhibitor, the dosage ratio of aluminum sulfate / sulfate zinc is 10:1 - 20:1, and the total dosage of the composite inhibitor is: 8.0 - 11.6 Kg / T for roughing, 4.0 - 5.3 Kg / T for cleaning; In the said composite collector, the dosage ratio of phthalic acid, N-hydroxyphthalimide ammonium, and o-carboxybenzohydroxamic acid is 5:2:1 - 7:3:1, and the total dosage of the composite collector is: 5.0 - 6.67 Kg / T for roughing, 4.0 - 6.0 Kg / T for cleaning, 1.5 - 2.0 Kg / T for scavenging.

2. The process for efficiently separating bastnasite and monazite from mixed rare earth concentrates according to claim 1, wherein, The middlings from the second-stage cleaning of the bastnaesite rough concentrate and the scavenging of the bastnaesite rough tailings are combined and returned to the roughing operation.

3. The process for efficiently separating bastnasite and monazite from mixed rare earth concentrates according to claim 1, characterized in that, The total dosage of the foaming agent octanoic acid is: 1.5 - 2.0 Kg / T for roughing, 6.0 - 8.5 Kg / T for cleaning.

4. The process for efficiently separating bastnasite and monazite from mixed rare earth concentrates according to claim 1, characterized in that, In step S1, the centrifugal gravity separation equipment is a Nelson concentrator. The content of -500 mesh in the gravity separation concentrate is 60% - 65%, the content of -5um is less than 1.0%, the content of -500 mesh in the tailings is greater than 90%, and the content of -5um is greater than 8%.

5. The process for efficiently separating bastnasite and monazite from mixed rare earth concentrates according to claim 1, characterized in that, In step S1, the fine grinding equipment is an Isa mill. After grinding and mixing with the gravity separation tailings, the particle size of the ore sample is 88% - 93% for -500 mesh, and the content of -5um is less than 15%.

6. The process for efficiently separating bastnasite and monazite from mixed rare earth concentrates according to claim 1, characterized in that, During the roughing, cleaning, and scavenging processes in steps S2, S3, and S4, the pH is 4.0 - 5.0, and the concentration is 60% - 70%.

7. The process for efficiently separating bastnasite and monazite from mixed rare earth concentrates according to claim 1, characterized in that, The action time of the composite inhibitor is 2 - 3 min, the action time of the collector is 3 - 5 min, and the action time of the foaming agent is 1 - 2 min.

8. The process for efficiently separating bastnaesite and monazite from mixed rare earth concentrates according to claim 1, characterized in that, The flotation time: the roughing time is 7 - 10 min, the scavenging time is 3 - 5 min, and the cleaning time is 3 - 5 min.

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