Method for enriching and separating tin and iron through tin tailing pre-discarding-reduction roasting

Abstract

The invention relates to a method for enriching and separating tin and iron through tin tailing pre-discarding-reduction roasting, and belongs to the technical field of solid waste resource utilization. The tin tailings are screened and classified into coarse-fraction tin tailings and fine-fraction tin tailings; the coarse-fraction tin tailings are subjected to ore grinding-centrifugal coarse scavenging separation, and the fine-fraction tin tailings are subjected to centrifugal coarse scavenging separation; mixing the coarse-fraction coarse scavenging centrifugal concentrate and the fine-fraction coarse scavenging centrifugal concentrate to obtain tin-iron symbiotic pre-enriched concentrate, and mixing the tailings to obtain centrifugal tailings; the centrifugal tailings are subjected to high-intensity magnetic rough sweeping cascade separation, iron pre-enriched concentrate is obtained after concentrate mixing, and the tailings subjected to high-intensity magnetic separation serve as final tailings to be discarded; the obtained tin-iron symbiotic pre-enriched concentrate is subjected to tin volatilization / iron magnetization reduction roasting-ore grinding-low intensity magnetic separation grading, and iron ore concentrate I is obtained while tin is volatilized; and the obtained iron pre-enriched concentrate is subjected to magnetizing roasting, ore grinding and low-intensity magnetic separation grading, and iron concentrate II is obtained. The device has the advantages of high operability, high production efficiency, good sorting effect and the like.

Description

Technical Field

[0001] This invention relates to a method for pre-disposal of tin tailings followed by reduction roasting to enrich and separate tin and iron, belonging to the field of solid waste resource utilization technology. Background Technology

[0002] Due to the inherent characteristics of tin ore resources, such as numerous valuable components and complex intergrowth relationships, coupled with uneven mining practices and outdated beneficiation technologies, a large amount of valuable metals are lost to tin tailings. According to incomplete statistics, my country's existing tin tailings contain over 800,000 tons of tin and over 100 million tons of iron. The large-scale stockpiling of tin tailings not only wastes valuable metals but also causes serious environmental pollution, affecting the local ecological balance and the physical and mental health of residents. Therefore, the secondary resource development and green integrated utilization of tin tailings is urgently needed.

[0003] Due to the complex phase composition of tin tailings, which contains low-grade cassiterite closely associated with iron-bearing minerals, and with some iron existing isomorphously within the cassiterite lattice, using a single beneficiation technology such as gravity separation or magnetic separation suffers from drawbacks such as recovering only one type of metal, a long process flow, and low tin-iron recovery rates, making it difficult to achieve efficient separation and recovery of tin and iron. Combining multiple beneficiation technologies, such as gravity separation and magnetic separation, to recover tin and iron not only overcomes the problem of recovering only one type of metal but also relatively reduces the process flow while increasing the recovery rate. However, relying solely on combined beneficiation technologies is insufficient to separate and recover tin and iron, resulting in severe tin-iron intermingling in the concentrate, which affects tin and iron smelting. Volatile roasting technology can achieve efficient separation of tin and iron during the roasting stage of tin tailings. However, volatile roasting technology also suffers from high energy consumption; therefore, reducing the amount of feed material before roasting can save some energy. Therefore, based on mineral processing technology and volatile roasting, a new technology for pre-tailing and efficient separation of tin and iron is developed. This technology can not only effectively enrich tin and iron minerals in tin tailings and reduce subsequent feed to lower energy consumption, but also achieve efficient separation of tin and iron. This achieves the goal of efficient recovery and separation of tin and iron elements in tin tailings, and realizes the comprehensive recovery and utilization of tin tailings. Summary of the Invention

[0004] To overcome the problems existing in the background technology, this invention provides a method for pre-disposal of tin tailings followed by reduction roasting for tin-iron enrichment and separation. This invention employs a combined gravity and magnetic separation technique to pre-dispose of tin tailings, reducing the cost of subsequent reduction roasting while pre-enriching and separating tightly coexisting tin-iron minerals from iron-containing minerals with high individual liberation. Subsequently, a roasting-grinding-magnetic separation technique is used, achieving tin-iron separation through simultaneous tin volatilization roasting and iron magnetization roasting. This invention has advantages such as strong operability, high production efficiency, and good separation effect.

[0005] The present invention is achieved through the following technical solution.

[0006] A method for enriching and separating tin-iron ore through pre-tailings disposal and reduction roasting includes the following steps:

[0007] (1) The tin tailings are screened and classified into coarse-grained tin tailings and fine-grained tin tailings.

[0008] (2) The coarse-grained tin tailings in step (1) are separated by grinding-centrifugal coarse scavenging, and the fine-grained tin tailings are separated by centrifugal coarse scavenging; the coarse-grained and fine-grained coarse scavenging centrifugal concentrates are mixed to obtain tin-iron symbiotic pre-enriched concentrates, and the tailings are mixed to obtain centrifugal tailings.

[0009] (3) The centrifugal tailings in step (2) are separated by strong magnetic coarse sweeping step separation. The concentrate is mixed to obtain iron pre-enriched concentrate. The tailings separated by strong magnetic separation are discarded as final tailings.

[0010] (4) The tin-iron symbiotic pre-enriched concentrate obtained in step (2) is subjected to tin volatilization / iron magnetization reduction roasting-grinding-weak magnetic separation, and iron concentrate I is obtained at the same time as tin volatilization;

[0011] (5) The iron pre-enriched concentrate obtained in step (3) is subjected to magnetization roasting-grinding-weak magnetic separation to obtain iron concentrate II.

[0012] The grading particle size in step (1) is divided into +0.05mm and -0.05mm particle sizes.

[0013] In step (2), the centrifuge drum speed is controlled at 800 rpm-980 rpm; the slurry concentration is controlled at 10%-14%; and the centrifugation time is controlled at 7 min-16 min.

[0014] In step (3), the magnetic field strength of the strong magnetic separation is controlled between 1.0T and 1.6T.

[0015] In step (4), the mass ratio of the tin-iron symbiotic pre-enriched concentrate to the reducing agent is 1:0.16-1:0.20, the roasting temperature is controlled at 1000℃-1050℃, and the roasting holding time is controlled at 2h-3h.

[0016] In step (5), the mass ratio of iron pre-enriched concentrate to reducing agent is 1:0.14-1:0.20, the roasting temperature is controlled at 750℃-900℃, and the roasting holding time is controlled at 60min-160min.

[0017] The beneficial effects of this invention are:

[0018] 1. This invention uses a stepped centrifugal-step magnetic separation technology to achieve the pre-enrichment and separation between densely coexisting tin-iron minerals and iron-containing minerals with high individual dissociation. While pre-discarding tailings, it achieves the pre-enrichment of tin and iron, reducing the amount of feed material and roasting cost in subsequent roasting.

[0019] 2. This invention employs a simultaneous tin-iron volatilization / magnetic roasting-magnetic separation technology to process tin-iron symbiotic pre-enriched concentrate, allowing tin to volatilize during roasting to obtain iron concentrate I. Simultaneously, a reduction roasting-magnetic separation technology is used to process the iron pre-enriched concentrate to obtain iron concentrate II. This technology achieves highly efficient separation of tin and iron.

[0020] 3. This invention has the advantages of being easy to operate, convenient to produce, high production efficiency, and good sorting effect. It adopts the combined beneficiation and smelting technology, and the average iron grade in the obtained iron concentrate reaches more than 62%, the comprehensive iron recovery rate reaches more than 65%, and the tin volatilization rate reaches more than 80%. Attached Figure Description

[0021] Figure 1 This is a simplified process flow diagram of the present invention. Detailed Implementation

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0023] Example 1

[0024] like Figure 1 As shown, the tin tailings used in this example came from a factory in Yunnan Province, with a tin grade of 0.20% and an iron grade of 21.08%. The gangue minerals were mainly calcite, dolomite, and quartz. The beneficiation of this tin tailings was carried out as follows:

[0025] (1) Tin tailings are divided into coarse-grained tin tailings with a particle size greater than 0.050 mm and fine-grained tin tailings with a particle size less than 0.050 mm.

[0026] (2) The coarse-grained tin tailings from step (1) are ground to a fineness of -0.050 mm, which accounts for 85% of the total particle size. Then, a series of centrifugal gravity separation operations of "one coarse and one scavenger" are performed. The test conditions for coarsening are a centrifuge drum speed of 877 rpm, a slurry concentration of 10%, and a centrifugation time of 8 min, to obtain centrifuged concentrate 1. The test conditions for scavenging are a centrifuge drum speed of 918 rpm, a slurry concentration of 10%, and a centrifugation time of 14 min, to obtain centrifuged middlings 1.

[0027] (3) The fine-grained tin tailings from step (1) are subjected to a step-by-step centrifugal gravity separation operation consisting of a coarse and a scavenger. The coarse separation test conditions are a centrifuge drum speed of 980 rpm, a slurry concentration of 10%, and a centrifugation time of 8 min, resulting in centrifuged concentrate 2; the scavenger separation test conditions are a centrifuge drum speed of 980 rpm, a slurry concentration of 10%, and a centrifugation time of 16 min, resulting in centrifuged middlings 2.

[0028] (4) After mixing centrifuged concentrate 1, centrifuged middlings 1, centrifuged concentrate 2 and centrifuged middlings 2 from steps (2) and (3), a tin-iron symbiotic pre-enriched concentrate is obtained, and all tailings are mixed to obtain centrifuged tailings. The tin grade in the tin-iron symbiotic pre-enriched concentrate is 0.541%, and the comprehensive recovery rate is 89.57% (this comprehensive recovery rate is calculated relative to the recovery rate of the original tin tailings ore, and unless otherwise specified, the recovery rate in this article is calculated based on the recovery rate of the original tin tailings ore), and the iron grade is 28.18%, with a comprehensive recovery rate of 45.57%.

[0029] (5) The centrifugal tailings from step (4) are subjected to a tiered high-intensity magnetic separation operation of "coarse and scavenger". The magnetic field strength of the coarse separation is 1.4T, and magnetic concentrate is obtained after magnetic separation; the magnetic field strength of the scavenger separation is 1.6T, and magnetic concentrate is obtained after magnetic separation.

[0030] (6) The magnetic concentrate from step (5) is mixed with the magnetically separated ore to obtain the iron pre-enriched concentrate, and all the tailings are mixed to obtain the final tailings. The iron grade in the iron pre-enriched concentrate is 24.81%, and the overall recovery rate is 40.14%.

[0031] (7) The tin-iron symbiotic pre-enriched concentrate obtained in step (4) was subjected to simultaneous tin-iron volatilization / magnetic roasting-magnetic separation. The roasting conditions were as follows: the tin-iron symbiotic pre-enriched concentrate and the reducing agent lignite were mixed at a mass ratio of 1:0.2 and roasted at 1000℃ for 3 hours. At the same time as obtaining the roasted product, the tin volatilization rate reached 91.33% (this volatilization rate is calculated relative to the tin-iron symbiotic pre-enriched concentrate, the same below). At this time, the comprehensive tin recovery rate was 81.80%. The magnetic separation magnetic field strength was 0.25T. After the experiment, iron concentrate I with an iron grade of 62.46% and a comprehensive recovery rate of 36.30% was obtained.

[0032] (8) The iron pre-enriched concentrate obtained in step (6) was subjected to reduction roasting-magnetic separation. The roasting conditions were as follows: the iron pre-enriched concentrate and the reducing agent were mixed at a ratio of 1:0.18 and roasted at a roasting temperature of 850℃ for 160 min to obtain the roasted product. The magnetic separation magnetic field strength was 0.29T. After the experiment, iron concentrate II with an iron grade of 63.33% and a comprehensive recovery rate of 30.33% was obtained.

[0033] Comparative Example 1 (Different pre-tailing disposal schemes were used after tin tailings were graded)

[0034] The tin tailings used in this example are the same as those in Example 1. The tin tailings are then beneficiated, and the specific operations are as follows:

[0035] (1) Tin tailings are divided into coarse-grained tin tailings with a particle size greater than 0.050 mm and fine-grained tin tailings with a particle size less than 0.050 mm.

[0036] (2) The coarse-grained tin tailings from step (1) are ground to a fineness of -0.050 mm, which accounts for 85% of the total particle size. Then, a shaking table gravity separation is performed to obtain shaking table concentrate 1.

[0037] (3) The fine-grained tin tailings in step (1) are re-separated by shaking table to obtain shaking table concentrate 2.

[0038] (4) The shaking concentrate 1 and shaking concentrate 2 from steps (2) and (3) are mixed to obtain a tin-iron symbiotic pre-enriched concentrate, and all tailings are mixed to obtain shaking tailings. The tin grade in the tin-iron symbiotic pre-enriched concentrate is 0.297% with a comprehensive recovery rate of 58.03%, and the iron grade is 24.53% with a comprehensive recovery rate of 45.00%.

[0039] (5) The tailings from the shaking table in step (4) were subjected to cascaded high-intensity magnetic separation under the same experimental conditions as in Example 1. After magnetic separation, magnetic concentrate and magnetically separated ore were obtained. These were mixed to obtain iron pre-enriched concentrate, and all tailings were mixed to obtain the final tailings. The iron grade in the iron pre-enriched concentrate was 26.55%, and the overall recovery rate was 37.58%.

[0040] (6) The tin-iron symbiotic pre-enriched concentrate obtained in step (4) was subjected to simultaneous tin-iron volatilization / magnetic roasting-magnetic separation, with the same experimental conditions as in Example 1. At this time, the tin volatilization rate reached 90.57%, and the overall tin recovery rate was 52.56%. Meanwhile, the iron grade in iron concentrate I was 61.82%, and the overall recovery rate was 34.59%.

[0041] (7) The iron pre-enriched concentrate obtained in step (5) was subjected to reduction roasting-magnetic separation under the same experimental conditions as in Example 1. The iron grade in iron concentrate II was 62.58%, and the recovery rate was 27.61%.

[0042] In the preliminary operation of this comparative example, the pre-enrichment effect of shaking table gravity separation on iron was not much different from that of centrifugal gravity separation, but the pre-enrichment effect of shaking table gravity separation on tin was not ideal.

[0043] Comparative Example 2 (Changing the roasting and holding time of tin-iron symbiotic pre-enriched concentrate)

[0044] The roasting and holding time of the tin-iron co-enriched concentrate was reduced to 1 hour, while other conditions remained the same as in Example 1. The obtained tin volatilization rate was only 46.84%, the grade of iron concentrate I was 58.09%, and the overall recovery rate was 38.38%.

[0045] Example 2

[0046] A tin tailings deposit in Yunnan Province has a tin grade of 0.15% and an iron grade of 18.38%. The gangue minerals are mainly quartz, feldspar, and calcite. The beneficiation process for this tin tailings is as follows:

[0047] (1) Tin tailings are divided into coarse-grained tin tailings with a particle size greater than 0.050 mm and fine-grained tin tailings with a particle size less than 0.050 mm.

[0048] (2) The coarse-grained tin tailings from step (1) are ground to a fineness of -0.050 mm, accounting for 80% of the total particle size. Then, a series of centrifugal gravity separation operations are performed. In the roughing process, the centrifuge drum speed is 836 rpm, the slurry concentration is 12%, and the centrifugation time is 9 min, resulting in centrifuged concentrate 1. The scavenging test conditions are a centrifuge drum speed of 918 rpm, a slurry concentration of 12%, and a centrifugation time of 16 min, resulting in centrifuged middlings 1.

[0049] (3) The fine-grained tin tailings from step (1) are subjected to a cascade centrifugal gravity separation operation. In the roughing process, the centrifuge drum speed is 946 rpm, the slurry concentration is 13%, and the centrifugation time is 10 min to obtain centrifuged concentrate 2; the scavenging test conditions are a centrifuge drum speed of 980 rpm, a slurry concentration of 13%, and a centrifugation time of 16 min to obtain centrifuged middlings 2.

[0050] (4) After mixing centrifuged concentrate 1, centrifuged middlings 1, centrifuged concentrate 2, and centrifuged middlings 2 from steps (2) and (3), a tin-iron symbiotic pre-enriched concentrate is obtained. All tailings are then mixed to obtain centrifuged tailings. The tin grade in the tin-iron symbiotic pre-enriched concentrate is 0.465%, with a comprehensive recovery rate of 85.65%, and the iron grade is 29.63%, with a comprehensive recovery rate of 44.53%.

[0051] (5) The centrifugal tailings from step (4) are subjected to cascaded high-intensity magnetic separation. The magnetic field strength for roughing is 1.1T, yielding a magnetic concentrate; the magnetic field strength for scavenging is 1.4T, yielding a magnetically separated ore. The two are mixed to obtain an iron pre-enriched concentrate, and all tailings are mixed to obtain the final tailings. The iron grade in the iron pre-enriched concentrate is 22.88%, and the overall recovery rate is 43.57%.

[0052] (6) The tin-iron symbiotic pre-enriched concentrate obtained in step (4) was subjected to simultaneous tin-iron volatilization / magnetic roasting-magnetic separation. The roasting conditions were as follows: the tin-iron symbiotic pre-enriched concentrate was mixed with a reducing agent (lignite) at a ratio of 1:0.18 and roasted at 1000℃ for 2 hours. At the same time, the tin volatilization rate reached 88.06% and the overall tin recovery rate was 75.42%. The magnetic separation magnetic field strength was 0.2T. After the experiment, iron concentrate I with an iron grade of 63.67% and an overall recovery rate of 33.36% was obtained.

[0053] (7) The iron pre-enriched concentrate obtained in step (5) was subjected to reduction roasting-magnetic separation. The roasting conditions were as follows: the iron pre-enriched concentrate and the reducing agent (lignite) were mixed at a ratio of 1:0.20 and roasted at a roasting temperature of 750℃ for 100 min to obtain the roasted product. The magnetic separation magnetic field strength was 0.2T. After the experiment, iron concentrate II with an iron grade of 62.56% and a comprehensive recovery rate of 30.86% was obtained.

[0054] Comparative Example 1 (test conducted directly without sieving)

[0055] The tin tailings used in this example are the same as those in Example 2. The tin tailings are then beneficiated, and the specific operations are as follows:

[0056] Tin tailings were directly ground to a particle size of -0.050 mm, with 80% of the total particle size being 0.050 mm, and then subjected to centrifugal gravity separation. In the roughing process, the centrifuge drum speed was 946 rpm, the pulp concentration was 14%, and the centrifugation time was 7 min, yielding centrifuged concentrate. The scavenging conditions were a centrifuge drum speed of 980 rpm, a pulp concentration of 12%, and a centrifugation time of 16 min, yielding centrifuged middlings. The centrifuged concentrate and middlings were then mixed to obtain a mixed concentrate. The tin and iron grades in concentrate 1 were 0.225% and 26.55%, respectively, with recoveries of 47.45% and 45.69%. In concentrate 2, the tin and iron grades were 0.156% and 24.66%, respectively, with recoveries of 12.51% and 16.14%. In the mixed concentrate, the tin and iron grades were 0.206% and 59.96%, respectively, with recoveries of 26.03% and 61.83%. Overall, the pre-enrichment effect of tin and iron was not good.

[0057] Note: Unless otherwise specified, all percentage contents mentioned in this invention are percentage contents by mass.

[0058] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for enriching and separating tin and iron through pre-tailings disposal and reduction roasting of tin tailings, characterized in that... Includes the following steps: (1) The tin tailings are screened and classified into coarse-grained tin tailings and fine-grained tin tailings. (2) The coarse-grained tin tailings in step (1) are separated by grinding-centrifugal coarse scavenging, and the fine-grained tin tailings are separated by centrifugal coarse scavenging; the coarse-grained and fine-grained coarse scavenging centrifugal concentrates are mixed to obtain tin-iron symbiotic pre-enriched concentrates, and the tailings are mixed to obtain centrifugal tailings. (3) The centrifugal tailings in step (2) are separated by strong magnetic coarse sweeping step separation. The concentrate is mixed to obtain iron pre-enriched concentrate. The tailings separated by strong magnetic separation are discarded as final tailings. (4) The tin-iron symbiotic pre-enriched concentrate obtained in step (2) is subjected to tin volatilization / iron magnetization reduction roasting-grinding-weak magnetic separation, and iron concentrate I is obtained at the same time as tin volatilization; (5) The iron pre-enriched concentrate obtained in step (3) is subjected to magnetization roasting-grinding-weak magnetic separation to obtain iron concentrate II.

2. The method for pre-disposal, reduction roasting, tin-iron enrichment and separation of tin tailings according to claim 1, characterized in that: The grading particle size in step (1) is divided into +0.05mm and -0.05mm particle sizes.

3. The method for pre-disposal, reduction roasting, tin-iron enrichment and separation of tin tailings according to claim 1, characterized in that: In step (2), the centrifuge drum speed is controlled at 800 rpm-980 rpm; the slurry concentration is controlled at 10%-14%; and the centrifugation time is controlled at 7 min-16 min.

4. The method for pre-disposal, reduction roasting, tin-iron enrichment and separation of tin tailings according to claim 1, characterized in that: In step (3), the magnetic field strength of the strong magnetic separation is controlled between 1.0T and 1.6T.

5. The method for pre-disposal, reduction roasting, tin-iron enrichment and separation of tin tailings according to claim 1, characterized in that: In step (4), the mass ratio of the tin-iron symbiotic pre-enriched concentrate to the reducing agent is 1:0.16-1:0.20, the roasting temperature is controlled at 1000℃-1050℃, and the roasting holding time is controlled at 2h-3h.

6. The method for pre-disposal, reduction roasting, tin-iron enrichment and separation of tin tailings according to claim 1, characterized in that: In step (5), the mass ratio of iron pre-enriched concentrate to reducing agent is 1:0.14-1:0.20, the roasting temperature is controlled at 750℃-900℃, and the roasting holding time is controlled at 60min-160min.

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