A process method for separating crystalline graphite by quality

Abstract

The present invention discloses a process method for sorting crystalline graphite by medium, including: Step 1, obtaining flash flotation rough concentrate and flash flotation middling 1; Step 2, the flash flotation rough concentrate is reground and reselected to obtain concentrate 1. If the raw material in Step 1 is the mill outlet product / classifier return sand of the rough grinding operation of graphite raw ore, then enter Step 3 / 4; Step 3, combining flash flotation middling 1 and flash flotation middling 2 and entering the classification operation; Step 4, combining flash flotation middling 1 and flash flotation middling 2 and returning them to the raw ore rough mill; Step 5, combining the middling produced by conventional flotation scavenging and the middling with a fixed carbon grade lower than 60% in the middling produced by conventional flotation regrinding and reselecting, and then flotation to obtain the rough concentrate of middling re-selection and tailings 2. The middling with a fixed carbon grade higher than or equal to 60% in the middling produced by conventional flotation regrinding and reselecting is sequentially returned; Step 6, regrinding and reselecting the rough concentrate of middling re-selection to obtain concentrate 3 and the middling produced by multiple middling re-selections.

Description

Technical Field

[0001] The present invention relates to a method for beneficiating graphite, and more particularly to a process method for separating and beneficiating crystalline graphite by quality. Background Art

[0002] Graphite is not only widely used in general industrial and consumer fields, but also widely used in new energy, electronic information, aerospace, nuclear energy, military industry, biological medicine, etc., and is non-renewable.

[0003] Crystalline graphite ore is usually beneficiated by flotation to obtain concentrate with a relatively high fixed carbon content. In industrial practice, the beneficiation recovery rate is usually above 75%, but the highest is only 90%; the fixed carbon grade of the concentrate is usually 88-97%; the beneficiation process should protect the crystal morphology and crystal size of flake graphite as much as possible.

[0004] Under the existing technical conditions, most of the crystalline graphite beneficiation process technologies adopt the process flow of rough grinding and rough separation of the original ore by a ball mill, scavenging of the tailings of the rough separation, multiple regrinding and multiple re-selection of the rough concentrate (such as nine times of regrinding and ten times of cleaning) to improve the fixed carbon grade of the concentrate, protect the crystal morphology of graphite flakes, and ensure the graphite recovery rate. However, the disadvantage of the above existing process is that the graphite flakes are still severely damaged, and the large flake rate of graphite in the concentrate is usually less than 10%. Summary of the Invention

[0005] Object of the Invention: Aiming at the deficiencies of the above existing technologies, the present invention provides a process method for separating and beneficiating crystalline graphite by quality. Specifically, by using a flash flotation machine to apply the flash flotation process to recover large flake graphite dissociated in the rough grinding stage; by utilizing the advantage of high enrichment ratio of the flotation column to optimize the cleaning operation of regrinding and re-selection; by multi-stage series connection of flotation machines to ensure the beneficiation recovery rate; by separately regrinding and re-selecting the middlings to achieve the rapid removal of gangue.

[0006] The present invention is a technical solution proposed according to the characteristics that natural graphite has good flotability and some larger flake graphite is easily dissociated in the rough grinding stage of the original ore.

[0007] Technical Solution: A process method for separating and beneficiating crystalline graphite by quality, the steps are as follows:

[0008] Step 1: Feed the product at the outlet of the mill or the classifier return sand of the rough grinding operation of the graphite original ore into a flash flotation machine to obtain flash flotation rough concentrate and flash flotation middlings 1;

[0009] Step 2: The flash flotation rough concentrate is re-ground and re-selected 3-5 times to obtain concentrate 1, and the large flake rate of the concentrate 1 is 35-40%, and the fixed carbon grade is ≥94%. Among them:

[0010] If the number of regrinding and re-selection is 3 times, the product of Step 2 further includes flash flotation middlings 2, flash flotation middlings 3 and flash flotation middlings 4;

[0011] If the number of regrinding and re-selection is 4 times, the products of step two further include flash flotation middling 2, flash flotation middling 3, flash flotation middling 4, and flash flotation middling 5;

[0012] If the number of regrinding and re-selection is 5 times, the products of step two further include flash flotation middling 2, flash flotation middling 3, flash flotation middling 4, flash flotation middling 5, and flash flotation middling 6;

[0013] If the raw material entering the flash flotation machine in step one is the mill outlet product of the rough grinding operation of graphite raw ore, it enters step three; if the raw material entering the flash flotation machine in step one is the classifier return sand, it enters step four;

[0014] Step three: Combine the flash flotation middling 1 obtained in step one and the flash flotation middling 2 obtained in step two and enter the classification operation. After completion, enter step five, where:

[0015] The classifier return sand returns to the rough grinding operation;

[0016] The classifier overflow is subjected to rough selection by a conventional flotation process in a primary flotation machine to obtain a conventional flotation roughing concentrate and a conventional flotation roughing tailing. The conventional flotation roughing concentrate undergoes 5 to 10 times of regrinding and re-selection to obtain concentrate 2 and the middling produced by the conventional flotation regrinding and re-selection. The conventional flotation roughing tailing undergoes 1 to 2 times of scavenging to obtain tailing 1 and the middling produced by the conventional flotation scavenging, where:

[0017] The large flake rate of the concentrate 2 is 8 to 12%, and the fixed carbon grade ≥ 94%;

[0018] Step four: Combine the flash flotation middling 1 obtained in step one and the flash flotation middling 2 obtained in step two and return them to the rough grinding operation. After completion, enter step five, where:

[0019] The classifier overflow is subjected to rough selection by a conventional flotation process in a primary flotation machine to obtain a conventional flotation roughing concentrate and a conventional flotation roughing tailing. The conventional flotation roughing concentrate undergoes 5 to 10 times of regrinding and re-selection to obtain concentrate 2 and the middling produced by the conventional flotation regrinding and re-selection. The conventional flotation roughing tailing undergoes 1 to 2 times of scavenging to obtain tailing 1 and the middling produced by the conventional flotation scavenging, where:

[0020] The large flake rate of the concentrate 2 is 8 to 12%, and the fixed carbon grade ≥ 94%;

[0021] Step 5: Combine the middlings with a fixed carbon grade of less than 60% obtained from the middlings produced by the conventional flotation scavenging in Step 3 and the middlings produced by the conventional flotation regrinding and reseparation in Step 3, and perform 1-2 times of flotation to obtain the rough concentrate of the middlings reseparation. The underflow of the roughing is directly discarded to obtain Tailings 2. The middlings with a fixed carbon grade higher than or equal to 60% in the middlings produced by the conventional flotation regrinding and reseparation in Step 3 are sequentially returned; or

[0022] Combine the middlings with a fixed carbon grade of less than 60% obtained from the middlings produced by the conventional flotation scavenging in Step 4 and the middlings produced by the conventional flotation regrinding and reseparation in Step 4, and perform 1-2 times of flotation to obtain the rough concentrate of the middlings reseparation. The underflow of the roughing is directly discarded to obtain Tailings 2. The middlings with a fixed carbon grade higher than or equal to 60% in the middlings produced by the conventional flotation regrinding and reseparation in Step 4 are sequentially returned;

[0023] Step 6: Subject the rough concentrate of the middlings reseparation obtained in Step 5 to 3-5 times of regrinding and reseparation to obtain Concentrate 3 and multiple middlings produced by the middlings reseparation, where:

[0024] The large flake rate of the Concentrate 3 is 1-5%, and the fixed carbon grade ≥ 92%;

[0025] The middlings produced by the middlings reseparation are processed by the method of centrally returning to the roughing operation of the middlings reseparation.

[0026] Furthermore, the regrinding method is a stirred mill, the linear velocity of regrinding is 2-3 m / s, and the grinding time is 20-40 min.

[0027] Furthermore, the fineness of the mill outlet product in the rough grinding operation of the graphite raw ore in Step 1 is that the content of -0.15 mm accounts for 50-80%.

[0028] Furthermore, the classification operation adopts one of a spiral classifier, a hydrocyclone, and a vibrating screen.

[0029] Furthermore, the pulp concentration in the flash flotation operation is 40-70%.

[0030] Furthermore, flotation machines are selected for the rough scavenging operation and the middlings reseparation operation, and a flotation column is used for the cleaning operation.

[0031] Advantages of the present invention:

[0032] Compared with the existing conventional process, the present invention first adopts a flash flotation machine and performs separation by quality according to the different crystal grain sizes of graphite, so that large flake graphite is fully protected, fine flake graphite and graphite with complex dissemination are quickly separated, effectively improving the concentrate index and increasing the large flake rate of the concentrate product.

[0033] Specifically: By using a flash flotation machine and applying the flash flotation process, a flash flotation rough concentrate of graphite with a high degree of monomer dissociation is obtained, reducing the occurrence of over-grinding;

[0034] By using a flotation column with high separation accuracy, monomer gangue and graphite lean intergrowths entrained in the concentrate are removed as early as possible, reducing the generation of scale damage;

[0035] By adding a regrinding and reseparation operation for middlings alone, focusing on treating graphite lean intergrowths, the loss of recovery rate is reduced, and at the same time, part of the gangue is quickly removed to purify the separation environment. Description of the Drawings

[0036] Figure 1 This is a flow chart of a process method for fractional separation of crystalline graphite proposed by the present invention. Among them, in step one, the raw material entering the flash flotation machine is the product at the outlet of the mill in the rough grinding operation of graphite ore.

[0037] Figure 2 This is a flow chart of a process method for fractional separation of crystalline graphite proposed by the present invention. Among them, in step one, the raw material entering the flash flotation machine is the return sand of the classifier.

[0038] Figure 3 This is a flow chart of a graphite ore separation process under existing technical conditions. Detailed Description of the Invention

[0039] The following is a detailed description of the specific implementation manner of the present invention.

[0040] In this application: "+0.15mm" means a particle size greater than 0.15mm, where the "+" means greater than.

[0041] "-0.15mm" means a particle size less than 0.15mm, where the "-" means less than.

[0042] The large flake ratio is the content of the +0.15mm particle size fraction.

[0043] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0044] In this application, unless otherwise specified:

[0045] The classification operation uses one of a spiral classifier, a hydrocyclone, and a vibrating screen.

[0046] For the rough scavenging operation and the re - separation operation of middlings, flotation machines are selected, and for the cleaning operation, a flotation column is used.

[0047] The re - grinding method is a stirred mill, the linear velocity of re - grinding is 2 - 3 m / s, and the grinding time is 20 - 40 min.

[0048] Example 1

[0049] Take a crystalline graphite ore from a certain place in Heilongjiang. Through chemical analysis, the fixed - carbon grade of the raw ore is 11.64%, among which:

[0050] The content of +0.15mm flake graphite accounts for 21.60% of the total graphite content, and the graphite dissemination size is relatively fine;

[0051] The gangue minerals are mainly quartz, feldspar, muscovite, tremolite, kaolinite, chlorite, and limonite, pyrite, pyrrhotite, etc.

[0052] Taking this ore sample as the research object, a comparative experimental study on the process flow proposed by the present invention and the process flow under the existing technical conditions is carried out, focusing on the index of the large - flake ratio (the content of +0.15mm particle size) in the concentrate. Kerosene is used as the collector, and BK201 is used as the frother.

[0053] Figure 2 It is a flow chart of a process method for separating crystalline graphite by different qualities proposed by the present invention. Among them, in step one, the raw material entering the flash flotation machine is the return sand of the classifier.

[0054] As Figure 2 shown, a process method for separating crystalline graphite by different qualities is as follows:

[0055] A process method for separating crystalline graphite by different qualities is as follows:

[0056] Step one: Feed the return sand of the classifier into the flash flotation machine to obtain flash flotation rough concentrate and flash flotation middling 1;

[0057] Step two: The flash flotation rough concentrate undergoes 4 times of re - grinding and re - separation to obtain concentrate 1, flash flotation middling 2, flash flotation middling 3, flash flotation middling 4, and flash flotation middling 5, among which:

[0058] The large - flake ratio of the concentrate 1 is 38.8%, and the fixed - carbon grade is 94.22%;

[0059] Step three: Combine the flash flotation middling 1 obtained in step one and the flash flotation middling 2 obtained in step two, return them to the rough grinding operation, and then enter step four, among which:

[0060] The overflow of the classifier is subjected to a conventional flotation process, and the rougher concentrate and rougher tailings of the conventional flotation are obtained through one roughing in a flotation machine. The rougher concentrate of the conventional flotation is reground and reselected 8 times to obtain concentrate 2 and the middlings generated from the regrinding and reselecting of the conventional flotation (i.e., middlings 2 - 9 of the conventional flotation). The rougher tailings of the conventional flotation are scavenged once to obtain tailings 1 and the middlings generated from the scavenging of the conventional flotation (i.e., middling 1 of the conventional flotation), where:

[0061] The large flake ratio of concentrate 2 is 9.9%, and the fixed carbon grade is 95.19%;

[0062] Step 4: Combine the middlings with a fixed carbon grade lower than 60% among the middlings generated from the scavenging of the conventional flotation obtained in Step 3 and the middlings generated from the regrinding and reselecting of the conventional flotation obtained in Step 3, and then subject them to one flotation to obtain the rough concentrate of the reselected middlings. The underflow of the roughing is directly discarded to obtain tailings 2, and the middlings with a fixed carbon grade lower than 60% among the middlings generated from the regrinding and reselecting of the conventional flotation obtained in Step 3 are sequentially returned;

[0063] Step 5: Subject the rough concentrate of the reselected middlings obtained in Step 4 to 4 regrindings and 5 reselectings to obtain concentrate 3 and middlings 1 - 5 generated from the reselecting of the middlings, where:

[0064] The large flake ratio of concentrate 3 is 2.3%, and the fixed carbon grade is 92.46%;

[0065] The middlings 1 - 5 generated from the reselecting of the middlings are processed by the method of centrally returning to the roughing operation of the reselecting of the middlings.

[0066] Further, the regrinding method is a stirred mill, the linear velocity of the regrinding is 2 m / s, and the grinding time is 30 min.

[0067] Further, a spiral classifier is used for the classification operation.

[0068] Further, the pulp concentration in the flash flotation operation is 60%.

[0069] Further, a flotation machine is selected for the rough scavenging operation and the reselecting operation of the middlings, and a flotation column is used for the cleaning operation.

[0070] Figure 1 This is a flow chart of a process method for separating different qualities of crystalline graphite proposed by the present invention. Among them, the raw material entering the flash flotation machine in Step 1 is the product at the outlet of the mill in the rough grinding operation of the graphite raw ore. Its technical solution is generally the same as that of Figure 2 , and the main differences are:

[0071] The raw material used is the product at the outlet of the mill in the rough grinding operation of the graphite raw ore;

[0072] The middlings 1 and middlings 2 from flash flotation are first subjected to a classification operation, and the classified sand returned from the classifier is returned to the coarse grinding operation.

[0073] Figure 3 It is a flow chart of the beneficiation process of graphite ore under the existing technical conditions. As Figure 3 shown, the process flow under the existing technical conditions is as follows:

[0074] Step 1: After crushing the crystalline graphite raw ore, it is subjected to one-stage coarse grinding and classification to obtain the classified sand returned from the classifier and the overflow from the classifier. The classified sand returned from the classifier is returned to the coarse grinder for regrinding;

[0075] Step 2: The overflow from the above classifier is roughened by a flotation machine once to obtain rougher concentrate and rougher tailings. The rougher tailings are scavenged by a flotation machine once to obtain middlings 1 and tailings. The rougher concentrate is reground by a stirred mill 7 times and concentrated by a flotation column 8 times to obtain concentrate and middlings 2 - middlings 9. Among them, middlings 1 - middlings 6 are combined and sent to the middlings re-election operation, and middlings 7 - middlings 9 are sequentially returned to the previous operation.

[0076] By carrying out research on the optimal dosage of each reagent, the best reagent regime for the process flow proposed in the present invention and the process flow under the existing technical conditions is determined, and the concentrate products and tailings products of the two process flows are obtained respectively. Through the determination of the fixed carbon grade and the calculation of the recovery rate, the relevant results are shown in Table 1.

[0077] Table 1 Comparison of test results

[0078]

[0079] It can be seen from the results in Table 1 that by adopting the process flow proposed in the present invention, not only can the concentrate grade and recovery rate under the existing technical conditions be achieved, but also the large flake rate in the concentrate, that is, the yield of the +0.15 mm particle size fraction, has increased by nearly 10 percentage points, greatly improving the added value of the concentrate product. This also re - illustrates from a practical perspective that carrying out separation of graphite raw ore with different dissemination sizes is beneficial to the protection of large flakes during the beneficiation process. In addition, the improvement of large flakes will also provide more convenient conditions for improving the production efficiency of subsequent screening operations and spherical operations.

[0080] Example 2

[0081] A process method for separating graphite by different qualities is as follows:

[0082] Step 1: The product at the outlet of the mill or the classified sand returned from the classifier in the coarse grinding operation of the graphite raw ore is fed into a flash flotation machine to obtain flash flotation rough concentrate and middlings 1 from flash flotation;

[0083] Step 2: The flash flotation rough concentrate is reground and re - selected 3 times to obtain concentrate 1 and middlings 2 from flash flotation, middlings 3 from flash flotation and middlings 4 from flash flotation, where:

[0084] The large flake rate of the concentrate 1 is 35%, and the fixed carbon grade is 94.52%;

[0085] If the raw material entering the flash flotation machine in Step 1 is the mill outlet product of the rough grinding operation of graphite ore, it enters Step 3; if the raw material entering the flash flotation machine in Step 1 is the classifier return sand, it enters Step 4;

[0086] Step 3: Combine the flash flotation middling 1 obtained in Step 1 and the flash flotation middling 2 obtained in Step 2 and enter the classification operation. After completion, enter Step 5, where:

[0087] The classifier return sand is returned to the rough grinding operation;

[0088] The classifier overflow is subjected to rough selection by a conventional flotation process through a primary flotation machine to obtain a conventional flotation rough concentrate and a conventional flotation rough tailing. The conventional flotation rough concentrate undergoes regrinding and re-selection 5 times to obtain concentrate 2 and the middlings generated from the regrinding and re-selection of the conventional flotation (i.e., middlings 2 - 6 of the conventional flotation). The conventional flotation rough tailing undergoes 1 time of scavenging to obtain tailing 1 and the middlings generated from the scavenging of the conventional flotation (i.e., middling 1 of the conventional flotation), where:

[0089] The large flake rate of the concentrate 2 is 8%, and the fixed carbon grade is 94.71%;

[0090] Step 4: Combine the flash flotation middling 1 obtained in Step 1 and the flash flotation middling 2 obtained in Step 2 and return them to the rough grinding operation. After completion, enter Step 5, where:

[0091] The classifier overflow is subjected to rough selection by a conventional flotation process through a primary flotation machine to obtain a conventional flotation rough concentrate and a conventional flotation rough tailing. The conventional flotation rough concentrate undergoes regrinding and re-selection 5 times to obtain concentrate 2 and the middlings generated from the regrinding and re-selection of the conventional flotation (i.e., middlings 2 - 6 of the conventional flotation). The conventional flotation rough tailing undergoes 1 time of scavenging to obtain tailing 1 and the middlings generated from the scavenging of the conventional flotation (i.e., middling 1 of the conventional flotation), where:

[0092] The large flake rate of the concentrate 2 is 8%, and the fixed carbon grade is 94.15%;

[0093] Step 5: Combine the middlings generated from the scavenging of the conventional flotation obtained in Step 3 and the middlings generated from the regrinding and re-selection of the conventional flotation obtained in Step 3 with a fixed carbon grade lower than 60% and perform 1 time of flotation to obtain a rough concentrate for re-selection of the middlings. The underflow of the rough selection is directly discarded to obtain tailing 2; the middlings with a fixed carbon grade higher than or equal to 60% in the middlings generated from the regrinding and re-selection of the conventional flotation obtained in Step 3 are sequentially returned; or

[0094] The middlings with a fixed carbon grade lower than 60% in the middlings produced by the conventional flotation scavenging obtained in Step 4 and the middlings produced by the conventional flotation regrinding and reseparation obtained in Step 4 are combined and subjected to 1 flotation to obtain the rough concentrate of middlings reseparation. The underflow of the roughing is directly discarded to obtain Tailings 2. The middlings with a fixed carbon grade higher than or equal to 60% in the middlings produced by the conventional flotation regrinding and reseparation obtained in Step 4 are sequentially returned;

[0095] Step 6: The rough concentrate of middlings reseparation obtained in Step 5 is subjected to 3 times of regrinding and reseparation to obtain Concentrate 3 and Middlings 1 - Middlings 3 produced by middlings reseparation, where:

[0096] The large flake rate of the Concentrate 3 is 1%, and the fixed carbon grade is 92.26%;

[0097] Middlings 1 - Middlings 3 produced by middlings reseparation are processed by the method of centrally returning to the roughing operation of middlings reseparation.

[0098] Furthermore, the regrinding method is a stirred mill, the linear velocity of regrinding is 2 m / s, and the grinding time is 40 min.

[0099] Further, the fineness of the mill outlet product in the rough grinding operation of the graphite raw ore in Step 1 is that the content of -0.15 mm accounts for 50%.

[0100] Further, a spiral classifier is used for the classification operation.

[0101] Further, the pulp concentration in the flash flotation operation is 40%.

[0102] Further, flotation machines are selected for the rough scavenging operation and the middlings reseparation operation, and a flotation column is used for the cleaning operation.

[0103] Example 3

[0104] A process method for separating different qualities of crystalline graphite is as follows:

[0105] Step 1: The mill outlet product of the graphite raw ore rough grinding operation or the classifier return sand enters the flash flotation machine to obtain the flash flotation rough concentrate and Flash Flotation Middlings 1;

[0106] Step 2: The flash flotation rough concentrate is subjected to 5 times of regrinding and reseparation to obtain Concentrate 1 and Flash Flotation Middlings 2, Flash Flotation Middlings 3, Flash Flotation Middlings 4, Flash Flotation Middlings 5, and Flash Flotation Middlings 6, where:

[0107] The large flake rate of the Concentrate 1 is 38%, and the fixed carbon grade is 94.65%;

[0108] If the raw material entering the flash flotation machine in Step 1 is the mill outlet product of the rough grinding operation of the graphite ore concentrate, it enters Step 3; if the raw material entering the flash flotation machine in Step 1 is the classifier return sand, it enters Step 4;

[0109] Step 3: Combine the flash flotation middling 1 obtained in Step 1 and the flash flotation middling 2 obtained in Step 2 and enter the classification operation. After completion, enter Step 5, where:

[0110] The classifier return sand is returned to the rough grinding operation;

[0111] The classifier overflow is subjected to rough selection by a conventional flotation process through a primary flotation machine to obtain a conventional flotation rough concentrate and a conventional flotation rough tailings. The conventional flotation rough concentrate is reground and reselected 10 times to obtain concentrate 2 and the middlings produced by the conventional flotation regrinding and reselecting (i.e., middlings 3 - 12 of the conventional flotation). The conventional flotation rough tailings are scavenged 2 times to obtain tailings 1 and the middlings produced by the conventional flotation scavenging (i.e., middlings 1 - 2 of the conventional flotation), where:

[0112] The large flake ratio of the concentrate 2 is 11%, and the fixed carbon grade is 94.54%;

[0113] Step 4: Combine the flash flotation middling 1 obtained in Step 1 and the flash flotation middling 2 obtained in Step 2 and return them to the rough grinding operation. After completion, enter Step 5, where:

[0114] The classifier overflow is subjected to rough selection by a conventional flotation process through a primary flotation machine to obtain a conventional flotation rough concentrate and a conventional flotation rough tailings. The conventional flotation rough concentrate is reground and reselected 10 times to obtain concentrate 2 and the middlings produced by the conventional flotation regrinding and reselecting (i.e., middlings 3 - 12 of the conventional flotation). The conventional flotation rough tailings are scavenged 2 times to obtain tailings 1 and the middlings produced by the conventional flotation scavenging (i.e., middlings 1 - 2 of the conventional flotation), where:

[0115] The large flake ratio of the concentrate 2 is 11%, and the fixed carbon grade is 94.69%;

[0116] Step 5: Combine the middlings with a fixed carbon grade lower than 60% in the middlings produced by the conventional flotation scavenging obtained in Step 3 and the middlings produced by the conventional flotation regrinding and reselecting obtained in Step 3, and subject them to 2 - stage flotation to obtain a rough concentrate for re - selection of the middlings. The underflow of the rough selection is directly discarded to obtain tailings 2. The middlings with a fixed carbon grade higher than or equal to 60% in the middlings produced by the conventional flotation regrinding and reselecting obtained in Step 3 are sequentially returned; or

[0117] The middlings with a fixed carbon grade lower than 60% in the middlings produced by the conventional flotation scavenging obtained in Step 4 and the middlings produced by the conventional flotation regrinding and reseparation obtained in Step 4 are combined and subjected to 2-stage flotation to obtain the rough concentrate of the middlings reseparation. The underflow of the roughing is directly discarded to obtain Tailings 2. The middlings with a fixed carbon grade higher than or equal to 60% in the middlings produced by the conventional flotation regrinding and reseparation obtained in Step 4 are sequentially returned;

[0118] Step 6: The rough concentrate of the middlings reseparation obtained in Step 5 is subjected to 5-stage regrinding and reseparation to obtain Concentrate 3 and Middlings 1 - Middlings 5 produced by the middlings reseparation, where:

[0119] The large flake rate of the Concentrate 3 is 5%, and the fixed carbon grade is 92.24%;

[0120] Middlings 1 - Middlings 5 produced by the middlings reseparation are processed by the method of being centrally returned to the roughing operation of the middlings reseparation.

[0121] Furthermore, the regrinding method is a stirred mill, the linear velocity of regrinding is 3 m / s, and the grinding time is 20 min.

[0122] Further, the fineness of the product at the outlet of the mill in the rough grinding operation of the graphite raw ore in Step 1 is that the content of -0.15 mm accounts for 80%.

[0123] Further, a hydrocyclone is used for the classification operation.

[0124] Further, the pulp concentration in the flash flotation operation is 70%.

[0125] Further, flotation machines are selected for the rough scavenging operation and the middlings reseparation operation, and a flotation column is used for the cleaning operation.

[0126] Example 4

[0127] A process method for the fractional separation of crystalline graphite is as follows:

[0128] Step 1. The product at the outlet of the mill in the rough grinding operation of the graphite raw ore or the classifier return sand enters the flash flotation machine to obtain the flash flotation rough concentrate and Flash Flotation Middlings 1;

[0129] Step 2. The flash flotation rough concentrate is subjected to 4-stage regrinding and reseparation to obtain Concentrate 1 and Flash Flotation Middlings 2, Flash Flotation Middlings 3, Flash Flotation Middlings 4, and Flash Flotation Middlings 5, where:

[0130] The large flake rate of the Concentrate 1 is 36%, and the fixed carbon grade is 94.87%;

[0131] If the raw material entering the flash flotation machine in Step 1 is the product at the outlet of the mill in the rough grinding operation of the graphite raw ore, then enter Step 3; if the raw material entering the flash flotation machine in Step 1 is the classifier return sand, then enter Step 4;

[0132] Step 3: Combine the flash flotation middling 1 obtained in Step 1 and the flash flotation middling 2 obtained in Step 2 and feed them into a classification operation. After completion, proceed to Step 5, where:

[0133] The sand returned from the classifier is returned to the rough grinding operation;

[0134] The overflow from the classifier is subjected to a conventional flotation process and rougher selected by a primary flotation machine to obtain a rougher concentrate of conventional flotation and a rougher tailing of conventional flotation. The rougher concentrate of conventional flotation is reground and reselected 8 times to obtain concentrate 2 and middlings produced during the regrinding and reselecting of conventional flotation (i.e., middlings 2 - 9 of conventional flotation). The rougher tailing of conventional flotation is scavenged once to obtain tailing 1 and middlings produced during the scavenging of conventional flotation (i.e., middling 1 of conventional flotation), where:

[0135] The large flake rate of the concentrate 2 is 10%, and the fixed carbon grade is 94.58%;

[0136] Step 4: Combine the flash flotation middling 1 obtained in Step 1 and the flash flotation middling 2 obtained in Step 2 and return them to the rough grinding operation. After completion, proceed to Step 5, where:

[0137] The overflow from the classifier is subjected to a conventional flotation process and rougher selected by a primary flotation machine to obtain a rougher concentrate of conventional flotation and a rougher tailing of conventional flotation. The rougher concentrate of conventional flotation is reground and reselected 8 times to obtain concentrate 2 and middlings produced during the regrinding and reselecting of conventional flotation (i.e., middlings 2 - 9 of conventional flotation). The rougher tailing of conventional flotation is scavenged once to obtain tailing 1 and middlings produced during the scavenging of conventional flotation (i.e., middling 1 of conventional flotation), where:

[0138] The large flake rate of the concentrate 2 is 10%, and the fixed carbon grade is 94.87%;

[0139] Step 5: Combine the middlings produced during the scavenging of conventional flotation obtained in Step 3 and the middlings produced during the regrinding and reselecting of conventional flotation obtained in Step 3 with a fixed carbon grade lower than 60% and subject them to 2 flotation operations to obtain a rough concentrate of reselected middlings. The underflow from the rougher is directly discarded to obtain tailing 2. The middlings produced during the regrinding and reselecting of conventional flotation obtained in Step 3 with a fixed carbon grade higher than or equal to 60% are sequentially returned; or

[0140] Combine the middlings produced during the scavenging of conventional flotation obtained in Step 4 and the middlings produced during the regrinding and reselecting of conventional flotation obtained in Step 4 with a fixed carbon grade lower than 60% and subject them to 1 flotation operation to obtain a rough concentrate of reselected middlings. The underflow from the rougher is directly discarded to obtain tailing 2. The middlings produced during the regrinding and reselecting of conventional flotation obtained in Step 4 with a fixed carbon grade higher than or equal to 60% are sequentially returned;

[0141] Step 6: The middlings re-concentrate obtained in Step 5 is re-ground and re-concentrated 4 times to obtain Concentrate 3 and Middlings 1 - Middlings 4 produced by the re-concentration of the middlings, where:

[0142] The large flake rate of Concentrate 3 is 3%, and the fixed carbon grade is 92.56%;

[0143] Middlings 1 - Middlings 4 produced by the re-concentration of the middlings are processed by the method of being centrally returned to the roughing operation of the middlings re-concentration.

[0144] Furthermore, the re-grinding method is a stirred mill, the linear velocity of re-grinding is 2.5 m / s, and the grinding time is 30 min.

[0145] Further, the fineness of the product at the outlet of the mill for rough grinding of the graphite raw ore described in Step 1 is that the content of -0.15 mm accounts for 60%.

[0146] Further, a vibrating screen is used for the classification operation.

[0147] Further, the pulp density in the flash flotation operation is 50%.

[0148] Further, flotation machines are selected for the rough scavenging operation and the middlings re-concentration operation, and a flotation column is used for the cleaning operation.

[0149] The above has made a detailed description of the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention within the knowledge scope of those of ordinary skill in the art to which the present invention pertains.

Claims

1. A process method for separating crystalline graphite by medium, characterized in that, The steps are as follows: Step 1: Feed the product from the mill outlet of the rough grinding operation of graphite ore or the cyclone return sand of the classifier into a flash flotation machine to obtain flash flotation rough concentrate and flash flotation middlings 1; Step 2: The flash flotation rough concentrate is reground and reselected 3 to 5 times to obtain concentrate 1, and the large flake ratio of the concentrate 1 is 35 to 40%, and the fixed carbon grade ≥ 94%. Among them: If the number of regrinding and reselecting is 3 times, the products of Step 2 also include flash flotation middlings 2, flash flotation middlings 3, and flash flotation middlings 4; If the number of regrinding and reselecting is 4 times, the products of Step 2 also include flash flotation middlings 2, flash flotation middlings 3, flash flotation middlings 4, and flash flotation middlings 5; If the number of regrinding and reselecting is 5 times, the products of Step 2 also include flash flotation middlings 2, flash flotation middlings 3, flash flotation middlings 4, flash flotation middlings 5, and flash flotation middlings 6; If the raw material entering the flash flotation machine in Step 1 is the product from the mill outlet of the rough grinding operation of graphite ore, go to Step 3; if the raw material entering the flash flotation machine in Step 1 is the cyclone return sand, go to Step 4; Step 3: Combine the flash flotation middlings 1 obtained in Step 1 and the flash flotation middlings 2 obtained in Step 2 and feed them into a classification operation. After completion, go to Step 5. Among them: The cyclone return sand is returned to the rough grinding operation; The overflow of the classifier is subjected to rougher flotation by a conventional flotation process to obtain conventional flotation rougher concentrate and conventional flotation rougher tailings. The conventional flotation rougher concentrate is reground and reselected 5 to 10 times to obtain concentrate 2 and the middlings generated from the conventional flotation regrinding and reselecting. The conventional flotation rougher tailings are scavenged 1 to 2 times to obtain tailings 1 and the middlings generated from the conventional flotation scavenging. Among them: The large flake ratio of the concentrate 2 is 8 to 12%, and the fixed carbon grade ≥ 94%; Step 4: Combine the flash flotation middlings 1 obtained in Step 1 and the flash flotation middlings 2 obtained in Step 2 and return them to the rough grinding operation. After completion, go to Step 5. Among them: The overflow of the classifier is subjected to rougher flotation by a conventional flotation process to obtain conventional flotation rougher concentrate and conventional flotation rougher tailings. The conventional flotation rougher concentrate is reground and reselected 5 to 10 times to obtain concentrate 2 and the middlings generated from the conventional flotation regrinding and reselecting. The conventional flotation rougher tailings are scavenged 1 to 2 times to obtain tailings 1 and the middlings generated from the conventional flotation scavenging; The large flake ratio of the concentrate 2 is 8 to 12%, and the fixed carbon grade ≥ 94%; Step 5: Combine the middlings with a fixed carbon grade lower than 60% among the middlings generated from the conventional flotation scavenging obtained in Step 3 and the middlings generated from the conventional flotation regrinding and reselecting obtained in Step 3, and perform 1 to 2 times of flotation to obtain middlings re-election rough concentrate. The underflow of the rougher flotation is directly discarded to obtain tailings 2. The middlings with a fixed carbon grade higher than or equal to 60% among the middlings generated from the conventional flotation regrinding and reselecting obtained in Step 3 are sequentially returned; or The middlings with a fixed carbon grade lower than 60% in the middlings produced by the conventional flotation scavenging obtained in Step 4 and the middlings produced by the conventional flotation regrinding and reseparation obtained in Step 4 are combined and subjected to 1-2 times of flotation to obtain a rough concentrate for reseparation of the middlings. The underflow of the rough selection is directly discarded to obtain Tailings 2. The middlings with a fixed carbon grade higher than or equal to 60% in the middlings produced by the conventional flotation regrinding and reseparation obtained in Step 4 are sequentially returned. Step 6: The rough concentrate for reseparation of the middlings obtained in Step 5 is subjected to 3-5 times of regrinding and reseparation to obtain Concentrate 3 and multiple middlings produced by the reseparation of the middlings, where: The large flake rate of the Concentrate 3 is 1-5%, and the fixed carbon grade ≥ 92%; The middlings produced by the reseparation of the middlings are processed by the method of centrally returning to the rough selection operation of the reseparation of the middlings.

2. The method for separating crystalline graphite by medium as described in claim 1, wherein, The method of regrinding is a stirred mill, the linear velocity of regrinding is 2-3 m / s, and the grinding time is 20-40 min.

3. The crystalline graphite separation process method according to claim 1, characterized in that, The fineness of the mill outlet product of the rough grinding operation of the graphite raw ore described in Step 1 is that the content of -0.15 mm accounts for 50-80%.

4. The method for separating crystalline graphite by medium as claimed in claim 1, wherein The classification operation adopts one of a spiral classifier, a hydrocyclone, and a vibrating screen.

5. The method for separating crystalline graphite by different qualities according to claim 1, wherein, The pulp concentration in the flash flotation operation is 40-70%.

6. The method for separating crystalline graphite by medium as claimed in claim 1, wherein Flotation machines are selected for the rough scavenging operation and the reseparation operation of the middlings, and a flotation column is used for the cleaning operation.

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