Tin stone reselection-multi-gradient flotation combined enhanced recovery method

Abstract

The invention discloses a cassiterite reselection-multi-gradient flotation combined enhanced recovery method. The method comprises the following steps that cassiterite raw ore is crushed and then subjected to pre-desliming and wet ball milling; carrying out magnetic separation on the obtained ore grinding product; performing primary table separation on the non-magnetic product to obtain table concentrate 1 and table middling 1; carrying out secondary table separation on the obtained table middling 1 to obtain table concentrate 2 and table middling 2; the table concentrate 1 and the table concentrate 2 are combined to serve as final table concentrate; the obtained table middling 2 is reground, then one-time roughing, two-time concentration and two-time scavenging are carried out, and flotation concentrate 1 is obtained; the obtained mud table tailings 2 are combined and then subjected to one-time roughing, three-time concentration and two-time scavenging, and flotation concentrate 2 is obtained; and the flotation concentrate 1 and the flotation concentrate 2 are combined to serve as final flotation concentrate. According to the method, the cassiterite is separated through combination of gravity separation, classification and flotation, the high-grade tin concentrate is obtained through gravity separation of the table concentrator, then the low-grade tin concentrate is obtained through separation by adopting different flotation processes and reagent systems after middlings of different size fractions are classified, and the comprehensive recovery rate of raw ore is increased.

Description

Technical Field

[0001] The present invention relates to the field of mineral processing, and particularly to a combined enhanced recovery method for cassiterite gravity separation - multi - gradient flotation. Background Art

[0002] Tin is an important industrial metal, commonly used in the manufacture of solders, coatings, alloys, and various chemical products such as tin cans, tin foil, and lead - acid batteries, and is widely used in the electronics, food packaging, automotive, and construction industries. Cassiterite is the most important tin - containing mineral, and methods such as gravity separation and flotation are usually used for separation. Due to the relatively large density of cassiterite, there are significant differences from gangue minerals such as quartz, feldspar, and calcite. Therefore, high - grade cassiterite concentrate products can be obtained through gravity separation. However, cassiterite is brittle, and a large amount of fine - grained cassiterite will inevitably be produced during the crushing and grinding process. This part is difficult to recover through gravity separation, and if directly discarded as tailings, it will cause resource waste. The lower limit of the recovery particle size of flotation is lower than that of gravity separation. Therefore, through a reasonable flotation process and reagent system, fine - grained cassiterite can be effectively recovered. With the continuous development and utilization of cassiterite resources, it will become increasingly difficult to obtain cassiterite concentrate that meets the requirements of industrial production through a single separation method. Therefore, it is necessary to design a combined separation process for the efficient recovery of cassiterite. Summary of the Invention

[0003] The purpose of the present invention is to provide a combined enhanced recovery method for cassiterite gravity separation - multi - gradient flotation. This method combines multiple ore - dressing methods, adopts appropriate separation means and reagent systems for cassiterite ores of different particle sizes, realizes the efficient recovery of cassiterite, and improves resource utilization rate.

[0004] The present invention provides a combined enhanced recovery method for cassiterite gravity separation - multi - gradient flotation, which includes the following steps:

[0005] S1. After crushing the cassiterite raw ore, pre - desliming is carried out to obtain a crushed product and slime. Subsequently, the crushed product is wet - ball - milled to obtain a milled product.

[0006] S2. The milled product obtained in step S1 is subjected to magnetic separation to obtain a magnetic product and a non - magnetic product.

[0007] S3. The non - magnetic product obtained in step S2 is subjected to the first shaking table separation to obtain shaking table concentrate 1, shaking table middling 1, and shaking table tailings 1.

[0008] S4. The shaking table middling 1 obtained in step S3 is subjected to the second shaking table separation to obtain shaking table concentrate 2, shaking table middling 2, and shaking table tailings 2; Shaking table concentrate 1 and shaking table concentrate 2 are combined as the final shaking table concentrate, and shaking table tailings 1 are used as the final shaking table tailings.

[0009] S5. Regrind the middlings 2 of the shaking table obtained in step S4, and then conduct one rough selection, two fine selections, and two scavenging selections to obtain flotation concentrate 1 and flotation tailings 1;

[0010] S6. Combine the slime obtained in step S1 with the shaking table tailings 2 obtained in step S4 and then conduct one rough selection, three fine selections, and two scavenging selections to obtain flotation concentrate 2 and flotation tailings 2; Combine flotation concentrate 1 and flotation concentrate 2 as the final flotation concentrate, and combine flotation tailings 1 and flotation tailings 2 as the final flotation tailings.

[0011] Further, in step S1, the content of Sn in the cassiterite raw ore is 0.5 - 0.7%, the quartz content is 60 - 70%, the mica content is 10 - 20%, and the feldspar content is 10 - 15%.

[0012] Further, in step S1, the desliming concentration is 20 - 25%, the grinding concentration is 60 - 70%, and the content of particles with a particle size less than 74μm in the grinding product is 50 - 60%.

[0013] Further, in step S2, the magnetic separation pulp concentration is 20% - 30%, and the magnetic field intensity is 2000 - 4000 Gs.

[0014] Further, in steps S3 - S4, the technological conditions of the first shaking table separation and the second shaking table separation are the same. Specifically: the feed pulp concentration is 20% - 25%, the shaking table stroke is 10 - 12 mm, the stroke frequency is 350 - 370 times / min, the water flow rate is 2 - 3 L / min, and the bed surface inclination angle is 1 - 3°.

[0015] Further, in step S5, the grinding concentration of the regrinding is 60 - 70%, and the content of particles with a particle size less than 74μm in the grinding product is 50 - 60%;

[0016] In steps S5 - S6, the flotation pulp concentration for all flotation processes is 15% - 30%. The order of reagent addition is conditioner, inhibitor, and collector in sequence. The aeration volume is 0.2 m 3 / L, and the foam scraping time is 3 min.

[0017] Further, the one rough selection, two fine selections, and two scavenging selections described in step S5 are specifically rough - grade rough selection, rough - grade fine selection 1, rough - grade fine selection 2, rough - grade scavenging selection 1, and rough - grade scavenging selection 2;

[0018] The rough concentrate 1 obtained from the rough selection of coarse particle size is subjected to fine selection 1 of coarse particle size; the fine concentrate 1 obtained from the fine selection 1 of coarse particle size is subjected to fine selection 2 of coarse particle size; the fine concentrate obtained from the fine selection 2 of coarse particle size is the flotation concentrate 1; the rough tailings 1 obtained from the rough selection of coarse particle size are subjected to scavenging 1 of coarse particle size; the scavenging tailings 1 obtained from the scavenging 1 of coarse particle size are subjected to scavenging 2 of coarse particle size; the scavenging tailings 2 obtained from the scavenging 2 of coarse particle size are used as the flotation tailings 1; the middlings in the flotation operation are all returned to the previous operation in sequence to form a closed circuit.

[0019] The reagent regime for the rough selection of coarse particle size is as follows: the regulator is sodium carbonate, with a dosage of 300 - 600 g / t; the inhibitor is a reagent combination including sodium silicate and sodium fluorosilicate, where the mass ratio of sodium silicate to sodium fluorosilicate is (5 - 10):1, and this inhibitor is denoted as Y, with a dosage of 3000 - 5000 g / t; the collector is a reagent combination including oxidized paraffin soap, sodium dodecyl sulfonate, lead nitrate, and ethyl phthalate, where the mass ratio of oxidized paraffin soap:sodium dodecyl sulfonate:lead nitrate:ethyl phthalate is (120 - 200):(20 - 35):(15 - 20):1, and this collector is denoted as B1, with a dosage of 2000 - 3000 g / t.

[0020] The reagent regimes for the fine selection 1 of coarse particle size, the fine selection 2 of coarse particle size, the scavenging 1 of coarse particle size, and the scavenging 2 of coarse particle size are the same, specifically: the dosage of inhibitor Y is 1000 - 3000 g / t, and the dosage of collector B1 is 300 - 1000 g / t.

[0021] Furthermore, the one rough selection, three fine selections, and two scavengings described in step S6 are specifically the rough selection of fine particle size, the fine selection 1 of fine particle size, the fine selection 2 of fine particle size, the fine selection 3 of fine particle size, the scavenging 1 of fine particle size, and the scavenging 2 of fine particle size;

[0022] The rough concentrate 2 obtained from the rough selection of fine particle size is subjected to fine selection 1 of fine particle size; the fine concentrate 3 obtained from the fine selection 1 of fine particle size is subjected to fine selection 2 of fine particle size; the fine concentrate 4 obtained from the fine selection 2 of fine particle size is subjected to fine selection 3 of fine particle size; the fine concentrate obtained from the fine selection 3 of fine particle size is the flotation concentrate 2; the rough tailings 2 obtained from the rough selection of fine particle size are subjected to scavenging 1 of fine particle size; the scavenging tailings 3 obtained from the scavenging 1 of fine particle size are subjected to scavenging 2 of fine particle size; the scavenging tailings 4 obtained from the scavenging 2 of fine particle size are used as the flotation tailings 2; the middlings in the flotation operation are all returned to the previous operation in sequence to form a closed circuit.

[0023] The reagent regime for fine-grained roughing is as follows: The regulator is sodium carbonate with a dosage of 500 - 700 g / t; the inhibitor Y has a dosage of 5000 - 7500 g / t; the collector is a reagent combination including oxidized paraffin soap, sodium dodecyl sulfonate, lead nitrate, and tributyl phosphate. Among them, the mass ratio of oxidized paraffin soap : sodium dodecyl sulfonate : lead nitrate : tributyl phosphate is (120 - 200) : (20 - 35) : (1 - 5) : 1. This collector is denoted as B2 with a dosage of 2000 - 3000 g / t.

[0024] The reagent regimes for fine-grained cleaning 1, fine-grained cleaning 2, fine-grained cleaning 3, fine-grained scavenging 1, and fine-grained scavenging 2 are the same, specifically: The inhibitor Y has a dosage of 2000 - 3500 g / t, and the collector B2 has a dosage of 300 - 1500 g / t.

[0025] The principle of the present invention:

[0026] The present invention proposes a combined enhanced recovery method of cassiterite gravity separation - multi-gradient flotation. First, through coarse grinding, cassiterite and gangue minerals are fully monomerically dissociated. Subsequently, through two stages of shaking table separation, the dissociated cassiterite minerals are fully recovered to obtain a high-grade shaking table concentrate. Since cassiterite is relatively brittle, a large amount of fine-grained cassiterite will inevitably be produced during the grinding process, which is difficult to effectively recover by the shaking table and requires flotation to improve the recovery rate. At the same time, the shaking table itself has a certain classification effect, so there will be two types of middlings with different particle sizes. When directly combining them for flotation, the slime phenomenon will deteriorate the flotation effect and cannot achieve good separation between fine-grained cassiterite and gangue minerals. In view of this, the present invention adopts a multi-gradient flotation method, that is, the coarse-grained middlings and fine-grained middlings are separated using different reagent regimes and processes, which can obtain better separation indexes compared to combined flotation.

[0027] The beneficial effects of the present invention:

[0028] (1) The present invention reasonably formulates corresponding beneficiation plans for cassiterite ores with different particle sizes. First, desliming is carried out before grinding, which is beneficial to reducing the slime phenomenon; after coarse grinding, two-stage shaking table is carried out to obtain high-grade coarse-grained cassiterite concentrate; for the produced coarse-grained middlings and fine-grained middlings, different flotation processes and reagent regimes are adopted to obtain low-grade fine-grained cassiterite concentrate, thereby improving the overall recovery rate of the raw ore.

[0029] (2) The flotation collector in the present invention's plan is compounded from multiple reagents. Among them, the compounding of oxidized paraffin soap, sodium dodecyl sulfonate, and lead nitrate endows it with good collecting property and selectivity; ethyl phthalate used in coarse-grained flotation as a foaming agent is beneficial for the floating of cassiterite and improves the recovery rate; tributyl phosphate used in fine-grained flotation can improve the foam structure, reduce the adverse effects brought by the slime phenomenon, and improve the concentrate grade.

[0030] (3) All the equipment and reagents used in the present invention are conventional flotation ones, which are easy to be realized industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic flow chart of the method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to specific embodiments, but the protection scope of the present invention is not limited to the following specific embodiments.

[0033] Unless otherwise defined, all the technical terms used hereinafter have the same meanings as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the protection scope of the present invention.

[0034] Embodiment 1

[0035] The raw cassiterite ore used in this embodiment comes from a certain mine in Tengchong, Yunnan, with a Sn content of 0.68%. The main gangue minerals are quartz, mica and feldspar. The process flow chart is as Figure 1 shown, and the specific steps are as follows:

[0036] (1) The raw ore is crushed to a particle size of less than 3 mm using a jaw crusher and a pair-roll crusher, and after pre-desliming, it is wet ball-milled with a grinding concentration of 67% until the particle size of the mineral particles less than 0.074 mm accounts for 51%.

[0037] (2) The ground product is subjected to a magnetic separation operation with a magnetic field intensity set at 3000 Gs and a magnetic separation pulp concentration of 25% to obtain a magnetic product and a non-magnetic product.

[0038] (3) The non-magnetic product is subjected to a first shaking table operation with a feed pulp concentration of 24%, a shaking table stroke of 12 mm, a stroke frequency of 360 times / min, a water flow rate of 2.4 L / min, and a table inclination of 1.6° to obtain a shaking table concentrate 1, a shaking table middling 1 and a shaking table tailing 1.

[0039] (4) The shaking table middling 1 is subjected to a second shaking table separation with a feed pulp concentration of 24%, a shaking table stroke of 12 mm, a stroke frequency of 360 times / min, a water flow rate of 2.4 L / min, and a table inclination of 1.6° to obtain a shaking table concentrate 2, a shaking table middling 2 and a shaking table tailing 2. The shaking table concentrate 1 and the shaking table concentrate 2 are combined as the final shaking table concentrate, and the shaking table tailing 1 is used as the final shaking table tailing.

[0040] (5) The shaking table middling 2 (coarse middling) is reground with a grinding concentration of 67% until the particle size of the mineral particles less than 0.074 mm accounts for 45%.

[0041] (6) The ground ore product is subjected to one rough selection, two fine selections and two scavenging selections. The middlings in each flotation operation are returned to the previous operation in sequence to form a closed circuit, obtaining flotation concentrate 1 and flotation tailings 1. The reagent regime for the rough selection is as follows: the regulator is sodium carbonate with a dosage of 400 g / t; the inhibitor is a reagent combination including sodium silicate and sodium fluorosilicate, where the mass ratio of sodium silicate to sodium fluorosilicate is 6:1. This inhibitor is denoted as Y with a dosage of 3500 g / t; the collector is a reagent combination including oxidized paraffin soap, sodium dodecyl sulfonate, lead nitrate, and ethyl phthalate, where the mass ratio of oxidized paraffin soap:sodium dodecyl sulfonate:lead nitrate:ethyl phthalate is 150:30:18:1. This collector is denoted as B1 with a dosage of 2000 g / t. The reagent regime for the first fine selection is: the inhibitor Y has a dosage of 3000 g / t, and the collector B1 has a dosage of 550 g / t; the reagent regime for the second fine selection is: the inhibitor Y has a dosage of 1000 g / t, and the collector B1 has a dosage of 300 g / t. The reagent regime for the first scavenging selection is: the inhibitor Y has a dosage of 1750 g / t, and the collector B1 has a dosage of 1000 g / t; the reagent regime for the second scavenging selection is: the inhibitor Y has a dosage of 1750 g / t, and the collector B1 has a dosage of 1000 g / t.

[0042] (7) The sludge obtained in (1) and the shaking table tailings 2 obtained in (4) are combined (fine middlings) and subjected to one rough selection, three fine selections and two scavenging selections. The middlings in each flotation operation are returned to the previous operation in sequence to form a closed circuit, obtaining flotation concentrate 2 and flotation tailings 2. Flotation concentrate 1 and flotation concentrate 2 are combined as the final flotation concentrate, and flotation tailings 1 and flotation tailings 2 are combined as the final flotation tailings. The reagent regime for the rough selection is as follows: the regulator sodium carbonate has a dosage of 600 g / t; the inhibitor Y has a dosage of 6000 g / t; the collector is a reagent combination including oxidized paraffin soap, sodium dodecyl sulfonate, lead nitrate, and tributyl phosphate, where the mass ratio of oxidized paraffin soap:sodium dodecyl sulfonate:lead nitrate:tributyl phosphate is 160:25:5:1. This collector is denoted as B2 with a dosage of 2500 g / t. The reagent regime for the first fine selection is: the inhibitor Y has a dosage of 3000 g / t, and the collector B2 has a dosage of 1100 g / t; the reagent regime for the second fine selection is: the inhibitor Y has a dosage of 3000 g / t, and the collector B2 has a dosage of 600 g / t; the reagent regime for the third fine selection is: the inhibitor Y has a dosage of 2000 g / t, and the collector B2 has a dosage of 350 g / t. The reagent regime for the first scavenging selection is: the inhibitor Y has a dosage of 3000 g / t, and the collector B2 has a dosage of 1200 g / t; the reagent regime for the second scavenging selection is: the inhibitor Y has a dosage of 3000 g / t, and the collector B2 has a dosage of 1200 g / t.

[0043] The test results show that through the combined process of gravity separation - classification - flotation for the raw ore, a shaking table concentrate with a tin grade of 52.72% and a recovery rate of 46.52% can be obtained, as well as a flotation concentrate with a tin grade of 13.63% and a recovery rate of 25.06%. The comprehensive recovery rate of tin is 71.58%.

[0044] Example 2

[0045] The raw tin ore used in this example is from a certain mine in Tengchong, Yunnan, with a Sn content of 0.65%. The main gangue minerals are quartz, mica, and feldspar. The separation is carried out according to the following steps:

[0046] (1) The raw ore is crushed to a particle size of less than 3 mm using a jaw crusher and a pair - roll crusher. After pre - desliming, it is wet - ball - milled with a grinding concentration of 67% until the particle size fraction less than 0.074 mm in the mineral particles accounts for 51%.

[0047] (2) A magnetic separation operation is carried out on the milled product. The magnetic field intensity is set at 3000 Gs, and the magnetic separation pulp concentration is 25% to obtain magnetic products and non - magnetic products.

[0048] (3) A first shaking table operation is carried out on the non - magnetic product. The feed pulp concentration is 24%, the shaking table stroke is 12 mm, the stroke frequency is 360 times / min, the water flow rate is 2.4 L / min, and the bed surface inclination is 2.5° to obtain shaking table concentrate 1, shaking table middling 1, and shaking table tailings 1.

[0049] (4) A second shaking table separation is carried out on shaking table middling 1. The feed pulp concentration is 24%, the shaking table stroke is 12 mm, the stroke frequency is 360 times / min, the water flow rate is 2.4 L / min, and the bed surface inclination is 2.5° to obtain shaking table concentrate 2, shaking table middling 2, and shaking table tailings 2. Shaking table concentrate 1 and shaking table concentrate 2 are combined as the final shaking table concentrate, and shaking table tailings 1 is used as the final shaking table tailings.

[0050] (5) Shaking table middling 2 (coarse middling) is reground with a grinding concentration of 67% until the particle size fraction less than 0.074 mm in the mineral particles accounts for 45%.

[0051] (6) The ground ore product is subjected to one rough selection, two cleanings, and two scavengings. The middlings in each flotation operation are returned to the previous operation in sequence to form a closed circuit, obtaining flotation concentrate 1 and flotation tailings 1. The reagent regime for rough selection is as follows: the regulator is sodium carbonate with a dosage of 400 g / t; the inhibitor is a reagent combination including sodium silicate and sodium fluorosilicate, where the mass ratio of sodium silicate to sodium fluorosilicate is 6:1. This inhibitor is denoted as Y with a dosage of 3500 g / t; the collector is a reagent combination including oxidized paraffin soap, sodium dodecyl sulfonate, lead nitrate, and ethyl phthalate, where the mass ratio of oxidized paraffin soap:sodium dodecyl sulfonate:lead nitrate:ethyl phthalate is 150:30:18:1. This collector is denoted as B1 with a dosage of 2500 g / t. The reagent regime for the first cleaning is: the inhibitor Y has a dosage of 3000 g / t, and the collector B1 has a dosage of 550 g / t; the reagent regime for the second cleaning is: the inhibitor Y has a dosage of 1000 g / t, and the collector B1 has a dosage of 300 g / t. The reagent regime for the first scavenging is: the inhibitor Y has a dosage of 1750 g / t, and the collector B1 has a dosage of 1000 g / t; the reagent regime for the second scavenging is: the inhibitor Y has a dosage of 1750 g / t, and the collector B1 has a dosage of 1000 g / t.

[0052] (7) The slime obtained in (1) and the shaking table tailings 2 obtained in (4) are combined (fine middlings) and subjected to one rough selection, three cleanings, and two scavengings. The middlings in each flotation operation are returned to the previous operation in sequence to form a closed circuit, obtaining flotation concentrate 2 and flotation tailings 2. The flotation concentrate 1 and flotation concentrate 2 are combined as the final flotation concentrate, and the flotation tailings 1 and flotation tailings 2 are combined as the final flotation tailings. The reagent regime for rough selection is as follows: the regulator sodium carbonate has a dosage of 600 g / t; the inhibitor Y has a dosage of 6000 g / t; the collector is a reagent combination including oxidized paraffin soap, sodium dodecyl sulfonate, lead nitrate, and tributyl phosphate, where the mass ratio of oxidized paraffin soap:sodium dodecyl sulfonate:lead nitrate:tributyl phosphate is 160:25:5:1. This collector is denoted as B2 with a dosage of 2900 g / t. The reagent regime for the first cleaning is: the inhibitor Y has a dosage of 3000 g / t, and the collector B2 has a dosage of 1100 g / t; the reagent regime for the second cleaning is: the inhibitor Y has a dosage of 3000 g / t, and the collector B2 has a dosage of 600 g / t; the reagent regime for the third cleaning is: the inhibitor Y has a dosage of 2000 g / t, and the collector B2 has a dosage of 350 g / t. The reagent regime for the first scavenging is: the inhibitor Y has a dosage of 3000 g / t, and the collector B2 has a dosage of 1200 g / t; the reagent regime for the second scavenging is: the inhibitor Y has a dosage of 3000 g / t, and the collector B2 has a dosage of 1200 g / t.

[0053] The test results show that after the raw ore is separated by the combined process of gravity separation - classification - flotation, a shaking table concentrate with a tin grade of 50.61% and a recovery rate of 49.84% can be obtained, as well as a flotation concentrate with a tin grade of 12.42% and a recovery rate of 28.35%. The comprehensive tin recovery rate is 78.19%.

[0054] Comparative Example 1

[0055] Compared with Example 1, only all the collectors used in flotation were replaced with lead benzohydroxamate (i.e., benzohydroxamic acid + lead nitrate), and other steps and conditions were exactly the same as those in Example 1.

[0056] The test results show that after the raw ore is separated by the combined process of gravity separation - classification - flotation, a shaking table concentrate with a tin grade of 52.34% and a recovery rate of 46.54% can be obtained, as well as a flotation concentrate with a tin grade of 14.52% and a recovery rate of 12.26%. The comprehensive tin recovery rate is 65.8%, indicating that the operating recovery rate of flotation is relatively low when using conventional cassiterite collectors.

[0057] Comparative Example 2

[0058] Compared with Example 1, the coarse - grained middlings and fine - grained middlings obtained after gravity separation were combined for flotation operations. The flotation process included one roughing, three cleanings, and two scavengings. The middlings from each flotation operation were returned to the previous operation in sequence to form a closed - circuit, obtaining flotation concentrate and flotation tailings. The reagent regime for roughing was as follows: the dosage of the regulator sodium carbonate was 600 g / t; the dosage of the inhibitor Y was 3500 g / t; the collector was a reagent combination including benzohydroxamic acid, sodium oleate, lead nitrate, tributyl phosphate, and coconut amine. Among them, the mass ratio of benzohydroxamic acid:sodium oleate:lead nitrate:tributyl phosphate:coconut amine was 200:25:20:3:1. This collector was denoted as B2, and the dosage was 2000 g / t. The reagent regime for the first cleaning was: the dosage of the inhibitor Y was 1200 g / t, and the dosage of the collector B2 was 400 g / t; the reagent regime for the second cleaning was: the dosage of the inhibitor Y was 1200 g / t, and the dosage of the collector B2 was 200 g / t; the reagent regime for the third cleaning was: the dosage of the inhibitor Y was 1200 g / t, and the dosage of the collector B2 was 200 g / t. The reagent regimes for the two scavengings were both: the dosage of the inhibitor Y was 1750 g / t, and the dosage of the collector B2 was 1000 g / t.

[0059] The test results show that after the raw ore is separated, a shaking table concentrate with a tin grade of 51.86% and a recovery rate of 46.49% can be obtained, as well as a flotation concentrate with a tin grade of 6.55% and a recovery rate of 10.81%. The comprehensive tin recovery rate is 57.3%, indicating that when the middlings from the shaking table are directly floated without classification, both the concentrate grade and recovery rate of the flotation operation are relatively low.

Claims

1. A combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation, characterized in that, It includes the following steps: S1. Crush the original cassiterite ore and then perform pre-desliming to obtain a crushed product and slime. Subsequently, wet ball milling is carried out on the crushed product to obtain a grinding product; S2. Perform magnetic separation on the grinding product obtained in step S1 to obtain a magnetic product and a non-magnetic product; S3. Perform the first shaking table separation on the non-magnetic product obtained in step S2 to obtain a shaking table concentrate 1, a shaking table middling 1, and a shaking table tailing 1; S4. Perform the second shaking table separation on the shaking table middling 1 obtained in step S3 to obtain a shaking table concentrate 2, a shaking table middling 2, and a shaking table tailing 2; Combine the shaking table concentrate 1 and the shaking table concentrate 2 as the final shaking table concentrate, and the shaking table tailing 1 as the final shaking table tailing; S5. Regrind the shaking table middling 2 obtained in step S4, and then perform one rough selection, two fine selections, and two scavenging selections to obtain a flotation concentrate 1 and a flotation tailing 1; S6. Combine the slime obtained in step S1 and the shaking table tailing 2 obtained in step S4 and then perform one rough selection, three fine selections, and two scavenging selections to obtain a flotation concentrate 2 and a flotation tailing 2; Combine the flotation concentrate 1 and the flotation concentrate 2 as the final flotation concentrate, and combine the flotation tailing 1 and the flotation tailing 2 as the final flotation tailing.

2. The combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation according to claim 1, wherein, In step S1, the content of Sn in the original cassiterite ore is 0.5 - 0.7%, the quartz content is 60 - 70%, the mica content is 10 - 20%, and the feldspar content is 10 - 15%.

3. The combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation according to claim 1, characterized in that, In step S1, the desliming concentration is 20 - 25%, the grinding concentration is 60 - 70%, and the content of particles with a particle size less than 74μm in the grinding product is 50 - 60%.

4. The combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation according to claim 1, characterized in that, In step S2, the magnetic separation pulp concentration is 20% - 30%, and the magnetic field intensity is 2000 - 4000 Gs.

5. The combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation according to claim 1, characterized in that, In steps S3 - S4, the technological conditions of the first shaking table separation and the second shaking table separation are the same. Specifically: the feed pulp concentration is 20% - 25%, the shaking table stroke is 10 - 12 mm, the stroke frequency is 350 - 370 times / min, the water flow rate is 2 - 3 L / min, and the bed surface inclination angle is 1 - 3°.

6. The combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation according to claim 1, characterized in that, In step S5, the grinding concentration for regrinding is 60-70%, and the content of particles with a particle size less than 74 μm in the grinding product is 50-60%; in all flotation processes from step S5 to S6, the pulp concentration of the flotation ore is 15%-30%, the order of reagent addition is conditioner, inhibitor, collector in sequence, the air inflow is 0.2 m 3 / L, and the froth scraping time is 3 min.

7. The combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation according to claim 1, characterized in that, The one rough selection, two fine selections, and two scavenging selections described in step S5 are specifically a coarse particle size rough selection, a coarse particle size fine selection 1, a coarse particle size fine selection 2, a coarse particle size scavenging selection 1, and a coarse particle size scavenging selection 2; Perform a coarse particle size fine selection 1 on the rough concentrate 1 obtained from the coarse particle size rough selection; perform a coarse particle size fine selection 2 on the fine concentrate 1 obtained from the coarse particle size fine selection 1; the fine concentrate obtained from the coarse particle size fine selection 2 is the flotation concentrate 1; perform a coarse particle size scavenging selection 1 on the rough tailing 1 obtained from the coarse particle size rough selection; perform a coarse particle size scavenging selection 2 on the scavenging tailing 1 obtained from the coarse particle size scavenging selection 1; the scavenging tailing 2 obtained from the coarse particle size scavenging selection 2 is used as the flotation tailing 1; the middlings in the flotation operation are all returned to the previous operation in sequence to form a closed circuit.

8. The combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation according to claim 7, characterized in that, The reagent regime for the coarse-grained roughing is as follows: the regulator is sodium carbonate with a dosage of 300 - 600 g / t; the inhibitor is a reagent combination including sodium silicate and sodium fluorosilicate, where the mass ratio of sodium silicate to sodium fluorosilicate is (5 - 10):

1. This inhibitor is denoted as Y with a dosage of 3000 - 5000 g / t; the collector is a reagent combination including oxidized paraffin soap, sodium dodecyl sulfonate, lead nitrate, and ethyl phthalate, where the mass ratio of oxidized paraffin soap:sodium dodecyl sulfonate:lead nitrate:ethyl phthalate is (120 - 200):(20 - 35):(15 - 20):

1. This collector is denoted as B1 with a dosage of 2000 - 3000 g / t; The reagent regimes for the first coarse-grained cleaning, the second coarse-grained cleaning, the first coarse-grained scavenging, and the second coarse-grained scavenging are the same, specifically: the dosage of inhibitor Y is 1000 - 3000 g / t, and the dosage of collector B1 is 300 - 1000 g / t.

9. The combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation according to claim 1, characterized in that, The one-time roughing, three-time cleaning, and two-time scavenging described in step S6 are specifically fine-grained roughing, the first fine-grained cleaning, the second fine-grained cleaning, the third fine-grained cleaning, the first fine-grained scavenging, and the second fine-grained scavenging; the roughing concentrate 2 obtained from the fine-grained roughing is subjected to the first fine-grained cleaning; the cleaning concentrate 3 obtained from the first fine-grained cleaning is subjected to the second fine-grained cleaning; the cleaning concentrate 4 obtained from the second fine-grained cleaning is subjected to the third fine-grained cleaning; the cleaning concentrate obtained from the third fine-grained cleaning is the flotation concentrate 2; the roughing tailings 2 obtained from the fine-grained roughing are subjected to the first fine-grained scavenging; the scavenging tailings 3 obtained from the first fine-grained scavenging are subjected to the second fine-grained scavenging; the scavenging tailings 4 obtained from the second fine-grained scavenging are used as the flotation tailings 2; the middlings in the flotation operation are all returned to the previous operation in sequence to form a closed circuit.

10. The combined enhanced recovery method of cassiterite gravity separation - multi - gradient flotation according to claim 9, characterized in that, The reagent regime for the fine-grained roughing is as follows: the regulator is sodium carbonate with a dosage of 500 - 700 g / t; the dosage of inhibitor Y is 5000 - 7500 g / t; the collector is a reagent combination including oxidized paraffin soap, sodium dodecyl sulfonate, lead nitrate, and tributyl phosphate, where the mass ratio of oxidized paraffin soap:sodium dodecyl sulfonate:lead nitrate:tributyl phosphate is (120 - 200):(20 - 35):(1 - 5):

1. This collector is denoted as B2 with a dosage of 2000 - 3000 g / t; The reagent regimes for the first fine-grained cleaning, the second fine-grained cleaning, the third fine-grained cleaning, the first fine-grained scavenging, and the second fine-grained scavenging are the same, specifically: the dosage of inhibitor Y is 2000 - 3500 g / t, and the dosage of collector B2 is 300 - 1500 g / t.

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