Beneficiation method for recovering fine-fraction cassiterite from table tailings

Abstract

The invention relates to a beneficiation method for recovering fine-fraction cassiterite from table tailings, and belongs to the technical field of beneficiation. The method comprises the following steps: (1) concentrating by a thickener; (2) grading operation of a cyclone; (3) desliming treatment; (4) flotation desulfurization; (5) magnetic separation iron removal operation; (6) hydrocyclone concentration operation: feeding the iron-removed tailings into a concentration hydrocyclone for concentration to obtain hydrocyclone settled sand and hydrocyclone overflow; and (7) cassiterite flotation operation. According to the method, for fine-fraction cassiterite which is uneven in cassiterite dissemination particle size, poor in monomer dissociation degree and high in iron, sulfur and mud, the technical indexes that the fine tin grade is larger than 35%, the tin-rich middling grade is larger than 2.5%, and the comprehensive tin recovery rate is larger than 65% can be obtained.

Description

Technical Field

[0001] The present application relates to the technical field of mineral processing, and in particular to a mineral processing method for recovering fine-grained cassiterite from shaking table tailings. Background Art

[0002] In the field of global tin resources, China occupies a prominent position with its rich reserves, but the complexity of resources also brings challenges. Among my country's tin mines, co-existing components account for as high as 88%, and single tin mines account for only a small number. As mining deepens, cassiterite minerals gradually reveal the characteristics of being poor, fine, and mixed, which puts higher requirements on the extraction and recovery technology of cassiterite. In particular, fine-grained and micro-fine-grained cassiterite has become a difficulty in current recovery technology due to its small particle size, dense embedding, and complex associated components.

[0003] In the field of mineral processing and beneficiation technology, the recovery of cassiterite, especially the recovery of fine-grained and micro-fine-grained cassiterite, constitutes a major technical challenge and economic test. Traditional beneficiation methods are mainly based on physical gravity separation technology. In particular, shaking tables are widely used for cassiterite separation due to their high enrichment ratio and ability to directly produce concentrates. However, there are obvious limitations in the treatment of fine-grained cassiterite, which is restricted by multiple factors such as particle size distribution, processing volume, floor space and recovery rate. In particular, the recovery effect of cassiterite with a particle size below -400 mesh is greatly reduced. In addition, cassiterite is brittle and fragile. The large amount of micro-fine-grained cassiterite produced during the crushing and grinding process has a fine particle size, densely embedded, complex associated and high mud content, which further increases the difficulty of recovery, resulting in low resource utilization and poor economic benefits.

[0004] Flotation is another important mineral processing method. It separates and enriches minerals based on the differences in physical and chemical properties of mineral surfaces, and has potential advantages for the recovery of fine-grained cassiterite. However, when single flotation is used to process cassiterite ores with high iron content, high sulfur content, and high mud content, there are problems such as high drug consumption, high production cost, low grade of flotation concentrate, and complex production process. The separation effect of cassiterite with severe mud content is not ideal. Therefore, single gravity separation or flotation methods are difficult to solve the problem of recovering fine-grained cassiterite with high iron content, high sulfur content, and high mud content in an economical and efficient manner. Summary of the invention

[0005] In order to solve or partially solve the problems existing in the related art, the present application provides a beneficiation method for recovering fine-grained cassiterite from shaking table tailings, which adopts a combined process flow of thickener concentration-cyclone classification-centrifuge desludging-flotation desulfurization-magnetic separation deiron removal-cyclone concentration-cassiterite flotation-vertical centrifuge pre-enrichment-shaking table selection to recover fine-grained cassiterite, and obtains technical indicators of tin fine ore grade greater than 35%, tin-rich medium ore grade greater than 2.5%, and tin comprehensive recovery rate greater than 65%. The present invention provides technical support for the efficient recovery of fine-grained cassiterite with uneven cassiterite distribution, poor monomer dissociation, high iron, high sulfur and high mud.

[0006] The specific steps of the present invention are as follows:

[0007] (1) Thickener thickening operation: The shaking table tailings are sent to the thickener for thickening, the overflow water is returned to the production cycle, and the underflow enters the classifying cyclone for classification.

[0008] (2) Cyclone classification operation: The bottom flow concentrated in step 1 is sent to the classification cyclone for classification to separate the coarse-grained low-grade ore and the fine-grained high-grade ore. The coarse-grained low-grade ore that settles in the cyclone is directly discarded, and the fine-grained high-grade ore that overflows from the cyclone enters the desludging operation.

[0009] (3) Centrifuge desliming: The fine-grained ore material overflowing from the grading cyclone in step 2 is sent to the centrifuge for desliming to remove the muddy components in the ore material (directly discard the tailings), and the bottom flow enters the flotation desulfurization operation.

[0010] (4) Flotation desulfurization operation: The ore after desludging in step 3 is sent to the desulfurization flotation machine for flotation desulfurization operation to separate minerals such as cassiterite and sulfur. The flotation concentrate is used as the sulfur concentrate, and the flotation tailings enter the magnetic separation iron removal operation.

[0011] (5) Magnetic separation and iron removal operation: The desulfurized flotation tailings in step 4 are sent to the magnetic separation operation for magnetic separation to remove iron impurities. The magnetic separation concentrate is used as the iron concentrate, and the magnetic separation tailings are sent to the cyclone concentration operation.

[0012] (6) Cyclone thickening operation: The iron-removed tailings in step 5 are sent to the thickening cyclone for thickening to increase the concentration of cassiterite flotation. The cyclone sedimentation enters the cassiterite flotation operation, and the cyclone overflow returns to the centrifuge for desludging.

[0013] (7) Cassiterite flotation operation: The cyclone sediment in step 6 is sent to the cassiterite flotation operation for further flotation operation to obtain cassiterite coarse concentrate, and the flotation tailings are directly discarded.

[0014] (8) Centrifuge pre-enrichment operation: The cassiterite coarse concentrate is sent to the centrifuge for pre-enrichment. The concentrate from the centrifuge pre-enrichment operation enters the shaking table for selection. The tailings from the centrifuge pre-enrichment operation are directly discarded.

[0015] (9) Shaking table concentration operation: The concentrate pre-enriched by the centrifuge in step 8 is sent to the shaking table for concentration, and two products, tin concentrate and tin-rich middling, are produced.

[0016] Furthermore, in the thickener thickening operation described in step 1, the thickener adopts an NXZ type central transmission high-efficiency thickener; the shaking table tailings has a concentration of 10% to 15%, a +200 mesh content of 20% to 30%, a tin grade of 0.06% to 0.1%, a -200 to +400 mesh content of 20% to 30%, a tin grade of 0.08% to 0.1%, a -400 mesh content of 40% to 60%, a tin grade of 0.2% to 0.3%, and after the ore is concentrated by the thickener, the concentration is 25% to 35%.

[0017] Furthermore, in the cyclone classification operation described in step 2, the cyclone is a φ250mm hydrocyclone, and the content of the classified overflow particle size -400 mesh is controlled to be above 70%.

[0018] Furthermore, in the centrifuge desludging operation described in step 3, the centrifuge is a Falcon centrifuge, and parameters such as the centrifuge speed and throttle valve pressure are precisely controlled. After desludging by the centrifuge, the -10um content in the ore is controlled below 10%, and the tin loss rate of the desludging operation is below 8%.

[0019] Furthermore, the flotation desulfurization operation described in step 4 has a process flow of a "one roughing + two scavenging + two fine" full flotation closed-loop process. Roughing, scavenging one, scavenging two, and fine selection one use flotation machines as sorting equipment, and fine selection two uses flotation columns as sorting equipment. The concentration of selected sulfur is adjusted to between 40% and 45%. The reagent system is: desulfurization activator 400-500g / t, desulfurization collector 30-40g / t, frother 20-30g / t, and the sulfur grade of the desulfurization tailings is controlled below 0.5%.

[0020] Furthermore, in the magnetic separation and iron removal operation described in step 5, the magnetic separator is a semi-countercurrent wet permanent magnetic separator with a magnetic field strength of 200 to 500 mT.

[0021] Furthermore, the cyclone concentration operation described in step 6 uses a φ75mm hydrocyclone, and the sedimentation concentration is controlled to be above 50% and the overflow concentration is controlled to be below 15%.

[0022] Furthermore, the cassiterite flotation operation described in step 7 has a process flow of a "two roughing + three sweeping + two fine" full flotation closed-circuit process, and the separation equipment uses a flotation machine as the separation equipment. The concentration of the selected ore is adjusted to between 50% and 55%. The reagent system is: cassiterite collector 400-800g / t, auxiliary adjusting agent 100-200g / t, and the output cassiterite rough concentrate grade is between 2% and 4%.

[0023] Furthermore, in the centrifuge pre-enrichment operation described in step 8, the centrifuge adopts an SL type centrifuge, and the parameters such as the centrifuge speed, feeding time and ore flow, rinsing water volume, and flushing water volume are precisely controlled. The process flow is a "one rough + one fine + one sweep" closed-loop process, the feed concentration is between 10% and 15%, the pre-enrichment operation concentrate enrichment ratio is 4 to 8 times, and the tin grade of the tailings is controlled below 0.5%.

[0024] Furthermore, in the shaking table selection operation described in step 9, the shaking table is a Yunnan tin shaking table, and the bed surface types include fine sand bed, grooved bed and fine mud bed; there are a total of 7 shaking tables in a single row, and according to the direction of ore flow, 1~3# are fine sand beds, 4~6# are grooved beds, and 7# is a fine mud shaking table; the matching hydraulic classification box is a Yunnan tin hydraulic classification box, which corresponds to the shaking table one by one, and is connected to the city through an aqueduct (the overall slope is 3 degrees), 1~2# models are YX-150, 3~4# models are YX-200, 5# model is YX-400, 6~7# model is YX-600; after the cassiterite coarse concentrate is selected by the shaking table, a tin concentrate with a tin grade greater than 35% and a tin-rich medium ore with a tin grade greater than 2.5% are produced.

[0025] Furthermore, in the flotation desulfurization operation described in step 4, the desulfurization activator can be copper sulfate, sulfuric acid, hydrochloric acid, etc., copper sulfate is diluted with water to a mass percentage concentration of 5% to 15% before use, and sulfuric acid and hydrochloric acid are directly added using stock solutions; the desulfurization collector can be a xanthate collector, a black medicine collector or other collectors, and is diluted with water to a mass percentage concentration of 5% to 15% before use; the foaming agent is pine oil, which is directly added using stock solution.

[0026] Furthermore, in the cassiterite flotation operation described in step 7, the cassiterite collector can be fatty acids, arsenic acid, alkyl hydroxamic acid, alkyl sulfonated succinic acid, etc., and a co-solvent (sodium hydroxide or sodium carbonate) is added in a certain proportion before use to make it better soluble in water, and water is added to dilute it to a mass percentage concentration of 5% to 15%. The auxiliary collector is an alcohol ester mixture, which is directly added using the original solution.

[0027] The beneficial effects of this application are:

[0028] (1) Compared with the traditional single cyclone method, the innovative combined process of "cyclone classification + centrifuge desludging" of the present invention realizes the simplification and optimization of the process flow, which not only ensures that the classification particle size accurately meets the high flotation standards, but also thoroughly removes the mud minerals, effectively solving the problem of cassiterite loss caused by mechanical entrainment in the cyclone. In addition, the process integrates advanced pretreatment technologies such as cyclone classification, centrifuge desludging, flotation desulfurization and magnetic separation iron removal, and constructs a set of efficient combined pretreatment system, which significantly weakens the interference of ore mud, sulfur minerals and magnetic minerals on the cassiterite separation process, and ensures the efficient and stable operation of the subsequent recovery process. At the same time, the unit consumption of reagents is significantly reduced, achieving a double improvement in cost-effectiveness.

[0029] (2) The present invention uses a cyclone to efficiently concentrate the magnetic tailings, which overcomes the problems caused by low concentration and secondary mud interference in the cassiterite flotation process. It not only stabilizes the key parameter of cassiterite flotation operation - flotation time, but also significantly reduces reagent consumption, achieving dual optimization of resource utilization and cost control, and laying a solid foundation for the stable operation and efficiency improvement of tin ore flotation process.

[0030] (3) The present invention creatively applies a centrifuge to the pre-enrichment process of cassiterite coarse concentrate. Compared with the traditional flotation column enrichment technology, it not only greatly enhances the stability of the process, but also significantly improves the enrichment ratio and recovery rate, thereby achieving efficient utilization of resources. More importantly, this technology effectively solves the problem of insufficient enrichment ratio in the cassiterite flotation process, thereby improving the recovery efficiency of the shaking table selection operation, and successfully overcomes the problem of being unable to produce qualified tin-rich medium ore.

[0031] (4) The present invention introduces a shaking table concentration process to produce two major products, tin concentrate and tin-rich medium ore, and successfully addresses the challenge of uneven particle size of cassiterite. In view of the problem that some cassiterite still exists in the form of intergrowths and inclusions after fine grinding, and the degree of monomer dissociation is limited, this process significantly improves the grade of tin concentrate and the comprehensive recovery rate of tin. This combined process not only meets the technical difficulties of efficient and comprehensive recovery of fine-grained cassiterite, but also shows excellent economic benefits in practical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0033] Figure 1 It is a schematic diagram of the process flow in Example 1 of the present application. DETAILED DESCRIPTION

[0034] The embodiments of the present application will be described in more detail below with reference to examples. Although the embodiments of the present application are shown in the examples, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and the scope of the present application can be fully communicated to those skilled in the art.

[0035] Example 1

[0036] use Figure 1 The process shown in the figure is used to flotate fine-grained cassiterite from the shaker tailings recovered from a polymetallic sulfide ore concentrator in Yunnan. The specific operation is as follows:

[0037] The original ore in this area is mainly composed of copper, tin and iron, and the ore composition is complex. The original ore is crushed and ground to -200 mesh content of 65%, and the process of flotation copper → flotation sulfur → magnetic iron → shaking table tin is used for separation. After separation, the concentration of shaking table tin tailings is 12.5%, +200 mesh content is 26.8%, tin grade is 0.063%, -200 ~ +400 mesh content is 24.3%, tin grade is 0.084%, -400 mesh content is 48.9%, tin grade is 0.214%.

[0038] The ore dressing method of the present invention is applied to recover fine-grained cassiterite in the shaking table tailings. The shaking table tin tailings flow by gravity to a central transmission high-efficiency thickener for concentration. The overflow water produced is returned to production for recycling. The concentrated ore (concentration 30.7%) is transported to a φ250mm hydrocyclone by a slurry pump for classification. The cyclone operates at a pressure of 45KPa. The tailings are directly discarded after classification sand settling. The classified overflow (-400 mesh content 80.2%, concentration 15.2%) flows by gravity to a centrifuge desludging buffer box and then enters a Falcon centrifuge for desludging. The centrifuge drum speed is 812 rpm, the throttle valve operates at a pressure of 1300KPa, the -10um content in the ore after desludging is 6.3%, and the produced mud ore is directly discarded.

[0039] The desludging product flows to the 1# mixing barrel by gravity. Water is added to the 1# mixing barrel to dilute the ore concentration to 43%. At the same time, 430g / t of 6.2% copper sulfate solution is added to activate the sulfur minerals. After activation, the minerals enter the 2# mixing barrel. 25g / t of 5% ethyl xanthate solution and 15g / t of pine oil are added to the 2# mixing barrel in turn. After slurry adjustment, the ore is fed into the flotation machine for the "one roughing, two sweeping, two fine" full flotation closed-circuit process for desulfurization and flotation. The intermediate products are returned to the corresponding operations in order. The roughing produces roughing concentrate and roughing concentrate. Tailings, the first scavenging is to add 10g / t of 5% ethyl xanthate solution and 10g / t of pine oil in the roughing tailings in turn, to produce scavenging concentrate and scavenging tailings, the second scavenging is not added with any reagents, to produce scavenging concentrate and scavenging tailings, the first concentration is to add 5g / t of pine oil to the roughing concentrate, to produce concentrate and tailings, the concentrate is transported to the second concentration (flotation column) by a slurry pump, the second concentration is not added with any reagents, to produce concentrate tailings and final sulfur concentrate, the sulfur content of the desulfurized tailings is 0.323%.

[0040] The tailings after sulfur removal flow into the semi-countercurrent permanent magnetic separator for iron removal. The magnetic field intensity is 500mT, and iron concentrate and iron tailings are produced. The iron tailings are transported to the φ75mm hydrocyclone for concentration by a slurry pump. The operating pressure of the hydrocyclone is 270KPa. The overflow of the hydrocyclone (concentration 10.4%) flows by gravity to the centrifuge desludging buffer box, and the hydrocyclone sedimentation (concentration 57%) flows by gravity to the 3# mixing barrel. Dilution water is added to the 3# mixing barrel to adjust the pulp concentration to 53%. A 6% cassiterite collector YK-SN (alkyl hydroxamic acid collector, prepared with sodium hydroxide at a ratio of 4:1) solution of 400g / t is added. After sufficient stirring, it flows by gravity into the 4# mixing barrel. Auxiliary collector SN-F is added to the 4# mixing barrel. 100g / t, after slurry adjustment, the ore is fed into the flotation machine for the "two roughing, three sweeping and two finishing" full flotation closed-circuit process to carry out cassiterite flotation, and the intermediate products are returned to the corresponding operations in sequence. Among them, the roughing one produces the roughing one concentrate and the roughing one tailings. The second roughing is to add 6% cassiterite collector YK-SN (alkyl hydroxamic acid collector, prepared with sodium hydroxide at a ratio of 4:1) solution 100g / t to the roughing one tailings to produce the rough two concentrate and rough two tailings. The first sweeping is to add 6% cassiterite collector YK-SN to the roughing two tailings. K-SN (alkyl hydroxamic acid collector, prepared with sodium hydroxide at a ratio of 4:1) solution 50g / t, produces sweep one concentrate and sweep one tailings, the second sweep is to add 6% cassiterite collector YK-SN (alkyl hydroxamic acid collector, prepared with sodium hydroxide at a ratio of 4:1) solution 50g / t, to the sweep one tailings, to produce sweep two concentrate and sweep two tailings, the third sweep is not added with any reagent, to produce sweep three concentrate and sweep three tailings, the first concentration is to add auxiliary collector SN-F 50g / t after mixing the coarse one concentrate and the coarse two concentrate, to produce concentrate one concentrate and concentrate one tailings, the second concentration is not added with any reagent, to produce concentrate two tailings and cassiterite rough concentrate, the tin grade of the cassiterite rough concentrate is 2.305%.

[0041] The cassiterite rough concentrate (concentration 12.4%) flows by gravity to the centrifuge pre-enrichment buffer box and enters the "one rough, one fine, one sweep" centrifuge pre-enrichment closed-loop process. The intermediate product returns to the corresponding process normally and is transported by a slurry pump. The operating parameters of the roughing SL centrifuge are: feeding time 110 seconds, interval time 5 seconds, flushing time 20 seconds, drum speed 210r / min, rinsing water volume 3m 3 / h, producing roughing concentrate and roughing tailings; the operating parameters of the SL centrifuge are feeding time 100 seconds, interval time 5 seconds, flushing time 22 seconds, drum speed 180r / min, rinsing water volume 2.5m 3 / h, producing scavenging concentrate and scavenging tailings, the tin content of scavenging tailings is 0.207%; the operating parameters of the SL centrifuge are feeding time 90 seconds, interval time 5 seconds, flushing time 18 seconds, drum speed 230r / min, rinsing water volume 4m3 / h; produces selected tailings and selected concentrates, with the tin grade of the selected concentrate being 13.516%.

[0042] The centrifuge pre-enriched and selected concentrate flows by gravity into the shaking table feed buffer box, and is slowly and evenly fed into the hydraulic classification box. The ore flow is classified in sequence under the action of gravity, and sinks into the shaking table feed trough for shaking table selection, producing tin concentrate with a tin grade of 36.237% and tin-rich middling with a tin grade of 3.87%, with a comprehensive recovery rate of 67.47%.

[0043] Example 2

[0044] The specific operation of the beneficiation method for recovering fine-grained cassiterite from shaking table tailings in a polymetallic sulfide ore beneficiation plant is as follows:

[0045] The concentration of shaking table tin tailings in this area is 13.2%, the content of +200 mesh size is 21.8%, the tin grade is 0.071%, the content of -200 to +400 mesh size is 22.5%, the tin grade is 0.090%, the content of -400 mesh size is 55.7%, the tin grade is 0.227%.

[0046] The ore dressing method of the present invention is applied to recover fine-grained cassiterite in the shaking table tailings. The shaking table tin tailings flow by gravity to the central transmission high-efficiency thickener for concentration, and the overflow water produced is returned to production for recycling. The concentrated ore (concentration 32.4%) is transported to a φ250mm hydrocyclone by a slurry pump for classification. The cyclone operates at a pressure of 47KPa. The tailings are directly discarded after classification sand settling. The classified overflow (-400 mesh content 85.1%, concentration 16.4%) flows by gravity to a centrifuge desludging buffer box and then enters a Falcon centrifuge for desludging. The centrifuge drum speed is 820 rpm, the throttle valve operates at a pressure of 1450KPa, the -10um content in the ore after desludging is 7.1%, and the produced mud ore is directly discarded.

[0047] The desludging product flows by gravity to the 1# mixing barrel. Water is added to the 1# mixing barrel to dilute the ore concentration to 44%. At the same time, 450g / t of 6.6% copper sulfate solution is added to activate the sulfur minerals. After activation, the minerals enter the 2# mixing barrel. 27g / t of 3% ethyl xanthate solution and 15g / t of pine oil are added to the 2# mixing barrel in turn. After slurry adjustment, the ore is fed into the flotation machine for the "one roughing, two sweeping, two fine" full flotation closed-circuit process for desulfurization and flotation. The intermediate products are returned to the corresponding operations in order. The roughing produces roughing concentrate and roughing concentrate. Tailings, the first scavenging is to add 13g / t of 5% ethyl xanthate solution and 10g / t of pine oil in the roughing tailings in turn, to produce scavenging concentrate and scavenging tailings, the second scavenging is not added with any reagents, to produce scavenging concentrate and scavenging tailings, the first concentration is to add 5g / t of pine oil to the roughing concentrate, to produce concentrate 1 and concentrate 1 tailings, the concentrate 1 is transported to the second concentration (flotation column) by a slurry pump, the second concentration is not added with any reagents, to produce concentrate 2 tailings and final sulfur concentrate, and the sulfur content of the desulfurized tailings is 0.213%.

[0048] The tailings after sulfur removal flow into the semi-countercurrent permanent magnetic separator for iron removal. The magnetic field intensity is 500mT, and iron concentrate and iron tailings are produced. The iron tailings are transported to the φ75mm hydrocyclone for concentration by a slurry pump. The operating pressure of the hydrocyclone is 275KPa. The overflow of the hydrocyclone (concentration 13.4%) flows by gravity to the centrifuge desludging buffer box, and the hydrocyclone sedimentation (concentration 56.3%) flows by gravity to the 3# mixing barrel. Dilution water is added to the 3# mixing barrel to adjust the pulp concentration to 53%. 300g / t of 7% cassiterite collector SN-705 (alkyl hydroxamic acid collector, prepared with sodium hydroxide at a ratio of 3:1) solution is added. After sufficient stirring, it flows by gravity into the 4# mixing barrel. Auxiliary collector SN-F is added to the 4# mixing barrel. 100g / t, after slurry adjustment, the ore is fed into the flotation machine for the "two roughing, three sweeping and two finishing" full flotation closed-circuit process to carry out cassiterite flotation, and the intermediate products are returned to the corresponding operations normally in sequence, among which the roughing one produces the roughing one concentrate and the roughing one tailings. The second roughing is to add 7% cassiterite collector SN-705 (alkyl hydroxamic acid collector, prepared with sodium hydroxide at a ratio of 3:1) solution 80g / t to the roughing one tailings to produce the rough two concentrate and rough two tailings. The first sweeping is to add 7% cassiterite collector SN-705 (alkyl hydroxamic acid collector, prepared with sodium hydroxide at a ratio of 3:1) to the roughing two tailings. The solution is 50g / t, and sweep concentrate and sweep tailings are produced. The second sweep is to add 7% cassiterite collector SN-705 (alkyl hydroxamic acid collector, prepared with sodium hydroxide in a ratio of 3:1) solution 50g / t to the sweep tailings, and produce sweep concentrate and sweep tailings. The third sweep is not added with any reagents, and sweep concentrate and sweep tailings are produced. The first concentration is to add auxiliary collector SN-F50g / t after mixing the coarse concentrate and the coarse concentrate, and produce concentrate and concentrate tailings. The second concentration is not added with any reagents, and produces concentrate tailings and cassiterite rough concentrate. The tin grade of the cassiterite rough concentrate is 3.105%.

[0049] The cassiterite coarse concentrate (concentration 11.6%) flows by gravity to the centrifuge pre-enrichment buffer box and enters the "one coarse, one fine, one sweep" centrifuge pre-enrichment closed-loop process. The intermediate product returns to the corresponding process normally and is transported by a slurry pump. The operating parameters of the roughing SL centrifuge are: feeding time 115 seconds, interval time 5 seconds, flushing time 20 seconds, drum speed 200r / min, rinsing water volume 3m 3 / h, producing rougher concentrate and rougher tailings; the operating parameters of the SL type centrifuge are feeding time 105 seconds, interval time 5 seconds, flushing time 22 seconds, drum speed 190r / min, rinsing water volume 2.5m 3 / h, producing scavenging concentrate and scavenging tailings, the tin content of scavenging tailings is 0.221%; the operating parameters of the SL centrifuge are feeding time 95 seconds, interval time 5 seconds, flushing time 18 seconds, drum speed 225r / min, rinsing water volume 4m3 / h; produces selected tailings and selected concentrates, with the tin grade of the selected concentrate being 15.473%.

[0050] The centrifuge pre-enriched and selected concentrate flows by gravity into the shaking table feed buffer box, and is slowly and evenly fed into the hydraulic classification box. The ore flow is classified in sequence under the action of gravity, and sinks into the shaking table feed trough for shaking table selection, producing tin concentrate with a tin grade of 37.635% and tin-rich middling with a tin grade of 3.05%, with a comprehensive recovery rate of 68.37%.

[0051] Example 3

[0052] The beneficiation method of a sulfide ore beneficiation plant in a certain place to recover fine-grained cassiterite from shaking table tailings is as follows:

[0053] The concentration of shaking table tin tailings in the area is 12.4%, the content of +200 mesh is 23.4%, the tin grade is 0.065%, the content of -200 to +400 mesh is 23.1%, the tin grade is 0.086%, the content of -400 mesh is 53.5%, and the tin grade is 0.246%.

[0054] The ore dressing method of the present invention is applied to recover fine-grained cassiterite in the shaking table tailings. The shaking table tin tailings flow by gravity to a central transmission high-efficiency thickener for concentration. The overflow water produced is returned to production for recycling. The concentrated ore (concentration 35.1%) is transported to a φ250mm hydrocyclone by a slurry pump for classification. The cyclone operates at a pressure of 50KPa. The tailings are directly discarded after classification sand settling. The classified overflow (-400 mesh content 84.3%, concentration 17.2%) flows by gravity to a centrifuge desludging buffer box and then enters a Falcon centrifuge for desludging. The centrifuge drum speed is 825 rpm, the throttle valve operates at a pressure of 1350KPa, the -10um content in the ore after desludging is 7.5%, and the produced mud ore is directly discarded.

[0055] The desludging product flows by gravity to the 1# mixing barrel. Water is added to the 1# mixing barrel to dilute the ore concentration to 41%. At the same time, 420g / t of 7.6% copper sulfate solution is added to activate the sulfur minerals. After sufficient stirring, it enters the 2# mixing barrel. 30g / t of 8% ethyl xanthate solution and 15g / t of pine oil are added to the 2# mixing barrel in turn. After slurry adjustment, the ore is fed into the flotation machine for the "one roughing, two sweeping, two fine" full flotation closed-circuit process for desulfurization and flotation. The intermediate products are returned to the corresponding operations in order. The roughing produces roughing concentrate and roughing concentrate. Tailings, the first scavenging is to add 10g / t of 8% ethyl xanthate solution and 10g / t of pine oil in turn to the roughing tailings to produce scavenging concentrate and scavenging tailings. The second scavenging is not added with any reagents, and produces scavenging concentrate and scavenging tailings. The first concentration is to add 5g / t of pine oil to the roughing concentrate to produce concentrate No. 1 concentrate and concentrate No. 1 tailings. The concentrate No. 1 concentrate is transported to the second concentration (flotation column) by a slurry pump. The second concentration is not added with any reagents, and produces concentrate No. 2 tailings and final sulfur concentrate. The sulfur content of the desulfurized tailings is 0.274%.

[0056] The tailings after sulfur removal flow into the semi-countercurrent permanent magnetic separator for iron removal. The magnetic field intensity is 350mT, and iron concentrate and iron tailings are produced. The iron tailings are transported to the φ75mm hydrocyclone for concentration by a slurry pump. The operating pressure of the hydrocyclone is 290KPa. The overflow of the hydrocyclone (concentration 12.7%) flows by gravity to the centrifuge desludging buffer box, and the hydrocyclone sedimentation (concentration 57.2%) flows by gravity to the 3# mixing barrel. Dilution water is added to the 3# mixing barrel to adjust the pulp concentration to 52%. 280g / t of cassiterite collector SN-705 (alkyl hydroxamic acid collector, prepared with sodium hydroxide at a ratio of 2:1) with a concentration of 8% is added. After sufficient stirring, it flows by gravity into the 4# mixing barrel. Auxiliary collector SN-F is added to the 4# mixing barrel. 100g / t, after slurry adjustment, the ore is fed into the flotation machine for the "two roughing, three sweeping and two finishing" full flotation closed-circuit process to carry out cassiterite flotation, and the intermediate products are returned to the corresponding operations in order. Among them, the roughing one produces the roughing one concentrate and the roughing one tailings. The second roughing is to add 100g / t of cassiterite collector SN-705 (alkyl hydroxamic acid collector, prepared with sodium carbonate at a ratio of 2:1) solution with a concentration of 8% to the roughing one tailings to produce rough two concentrates and rough two tailings. The first sweeping is to add 8% cassiterite collector S N-705 (alkyl hydroxamic acid collector, prepared with sodium carbonate at a ratio of 2:1) solution 50g / t, produces sweep one concentrate and sweep one tailings, the second sweep is to add 50g / t of cassiterite collector SN-705 (alkyl hydroxamic acid collector, prepared with sodium carbonate at a ratio of 3:1) solution with a concentration of 8% to the sweep one tailings, and produces sweep two concentrate and sweep two tailings, the third sweep is not added with any reagent, and produces sweep three concentrate and sweep three tailings, the first concentration is to add auxiliary collector SN-F 50g / t after mixing the coarse one concentrate and the coarse two concentrate, and produce concentrate one concentrate and concentrate one tailings, the second concentration is not added with any reagent, and produces concentrate two tailings and cassiterite rough concentrate, and the tin grade of the cassiterite rough concentrate is 2.405%.

[0057] The cassiterite coarse concentrate (concentration 13.6%) flows by gravity to the centrifuge pre-enrichment buffer box and enters the "one coarse, one fine, one sweep" centrifuge pre-enrichment closed-loop process. The intermediate products return to the corresponding process normally and are transported by slurry pumps. The operating parameters of the roughing SL centrifuge are: feeding time 117 seconds, interval time 5 seconds, flushing time 21 seconds, drum speed 195r / min, rinsing water volume 2.5m 3 / h, producing roughing concentrate and roughing tailings; the operating parameters of the SL type centrifuge are 125 seconds for feeding time, 5 seconds for interval time, 22 seconds for flushing time, 185r / min for drum speed, and 2.5m3 for rinsing water volume. 3 / h, producing scavenging concentrate and scavenging tailings, the tin content of scavenging tailings is 0.196%; the operating parameters of the SL centrifuge are feeding time 105 seconds, interval time 5 seconds, flushing time 19 seconds, drum speed 220r / min, rinsing water volume 3.5m 3 / h; produces selected tailings and selected concentrates, with the tin grade of the selected concentrate being 12.248%.

[0058] The centrifuge pre-enriched and selected concentrate flows by gravity into the shaking table feed buffer box, and is slowly and evenly fed into the hydraulic classification box. The ore flow is classified in sequence under the action of gravity, and sinks into the shaking table feed trough for shaking table selection, producing tin concentrate with a tin grade of 35.521% and tin-rich middling with a tin grade of 3.35%, with a comprehensive recovery rate of 68.08%.

[0059] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A beneficiation method for recovering fine-grained cassiterite from shaking table tailings, characterized in that: The following steps are involved: (1) Thickener thickening operation: The shaking table tailings are sent to the thickener for thickening to obtain a thick underflow with a concentration of 25% to 35%; (2) Cyclone classification operation: The dense underflow is sent to the classification cyclone for classification operation to obtain cyclone sedimentation coarse-grained low-grade ore and cyclone overflow fine-grained high-grade ore; during the classification operation, the content of the classification overflow particle size -400 mesh is controlled to be above 70%, the sedimentation concentration is controlled to be above 50%, and the overflow concentration is controlled to be below 15%; (3) Send the fine-grained high-grade ore into the centrifuge for desliming, and the -10um content in the deslimed ore is controlled below 10%; (4) sending the desludging ore material to a desulfurization flotation machine for flotation desulfurization operation to obtain flotation concentrate sulfur concentrate and flotation tailings; Among them, the flotation desulfurization process is a "one roughing + two sweeping + two fine" full flotation closed-circuit process, the reagent system is 400-500g / t of desulfurization activator, 30-40g / t of desulfurization collector, 20-30g / t of frother, and the sulfur content of the desulfurized tailings is controlled below 0.5%; (5) Magnetic separation and iron removal: The flotation tailings are subjected to magnetic separation to obtain magnetic concentrate as iron concentrate and iron removal tailings; (6) Cyclone thickening operation: the iron-removing tailings are sent to the thickening cyclone for thickening to obtain cyclone sand settling and cyclone overflow; (7) Cassiterite flotation operation: The cyclone sedimentation enters the cassiterite flotation operation for further flotation operation to obtain cassiterite rough concentrate; the process flow of the cassiterite flotation operation is a "two roughing + three sweeping + two fine" full flotation closed-circuit process; the reagent system is: cassiterite collector 400-800g / t, auxiliary adjusting agent 100-200g / t, and the output cassiterite rough concentrate grade is 2%-4%; (8) Centrifuge pre-enrichment operation: the cassiterite concentrate is sent to a centrifuge for pre-enrichment to obtain a pre-enriched cassiterite concentrate; (9) Shaking table concentration operation: The pre-enriched cassiterite concentrate is sent to the shaking table for concentration, thus obtaining high-grade tin concentrate and tin-rich medium ore.

2. A method for recovering fine-grained cassiterite from shaking table tailings according to claim 1, characterized in that: The process flow of the centrifuge pre-enrichment operation is a "one roughing + one fine + one sweeping" closed-circuit process, the feed concentration is 10% to 15%, the pre-enrichment operation concentrate enrichment ratio is 4 to 8 times, and the tin grade of the tailings is controlled below 0.5%.

3. A method for recovering fine-grained cassiterite from shaking table tailings according to claim 1, characterized in that: The desulfurization activator is copper sulfate, sulfuric acid or hydrochloric acid. Copper sulfate is diluted with water to a mass percentage concentration of 5% to 15% before use, and sulfuric acid and hydrochloric acid are directly added using stock solutions; the desulfurization collector is a xanthate collector or a black medicine collector, which is diluted with water to a mass percentage concentration of 5% to 15% before use; the foaming agent is pine oil, which is directly added using stock solution.

4. A method for recovering fine-grained cassiterite from shaking table tailings according to claim 1, characterized in that: The cassiterite collector is fatty acid, arsenic acid, alkyl hydroxamic acid or alkyl sulfonated succinic acid, which is added with a certain proportion of auxiliary solvent sodium hydroxide or sodium carbonate before use, and is diluted with water to a mass percentage concentration of 5% to 15%. The auxiliary collector is an alcohol ester mixture, which is directly added using the original solution.

5. A beneficiation method for recovering fine-grained cassiterite from shaking table tailings according to claim 1, characterized in that: In the step (1), the concentration of the shaking table tailings is 10% to 15%; the content of the +200 mesh size is 20% to 30% and the tin grade is 0.06% to 0.1%; the content of the -200 to +400 mesh size is 20% to 30% and the tin grade is 0.08% to 0.1%; the content of the -400 mesh size is 40% to 60% and the tin grade is 0.2% to 0.3%.

6. A method for recovering fine-grained cassiterite from shaking table tailings according to claim 5, characterized in that: The method can ensure that the grade of the final tin fine ore is greater than 35%, the grade of the tin rich medium ore is greater than 2.5%, and the comprehensive recovery rate of tin is greater than 65%.

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