Study on Beneficiation Process of a Tin Mine in South China

Xinyi silver rock tin metal porphyry ore deposits of tin, tin-containing ores, in addition to, but still contains a small amount of tungsten, molybdenum, bismuth, copper and other valuable elements. Therefore, it is necessary to select a reasonable beneficiation process to maximize the comprehensive recovery of the above elements and improve resource utilization. This paper describes in detail the experimental research on the beneficiation process of the tin mine, in order to provide technical basis for the development and utilization of the tin mine.

First, the nature of the ore

(1) Chemical composition

The results of chemical multi-element analysis show that the main valuable element in the ore is tin, the content of tin is 0.66%, followed by bismuth, molybdenum, tungsten, copper, etc., and comprehensive recovery can be considered in the beneficiation process. The results of multi-element analysis of ore minerals are shown in Table 1, and the results of tin phase analysis are shown in Table 2.

Table 1 Multi-element analysis results of ore /%

(Continued Table 1)

Table 2 Results of raw ore tin phase analysis /%

(2) Mineral composition

Metallic minerals are mainly cassiterite, molybdenite, bismuthinite, bubble bismuth, wolframite, scheelite, chalcopyrite, pyrite, hematite, hematite and other gangue minerals are mainly Quartz , topaz , followed by mica , fluorite , chlorite.

(3) Occurrence and mineral characteristics of valuable elements

The cassiterite is often in the form of granules or fine-grained stars or in the form of fine-grained aggregates, and a small number of fine veins or nets are embedded in gangue minerals such as quartz, topaz and mica. The particle size of the cassiterite is mostly between 0.03 and 0.1 mm and the minimum is 0.001 mm. The molybdenum is mainly composed of molybdenum ore. The molybdenum ore is impregnated with fine veins and scattered in the gangue minerals. A small amount of molybdenite is also embedded along the pyrite or stibnite or between the edges. The molybdenum ore has a particle size of generally 0.05 to 0.3 mm and a minimum of 0.001 mm. There are many strontium ore and sputum ore in the sputum, and a small amount of natural sputum. It was Bismuthinite shaped grains, fibers or short columnar dip disseminated gangue minerals, sulfide ore or chalcopyrite, pyrite, sphalerite and other neighbor mosaic form. The strontium ore has a particle size of generally 0.05 to 0.3 mm and a minimum of 0.001 mm. Copper is mainly present in chalcopyrite, occasionally a small amount of porphyrite or chalcopyrite. Chalcopyrite is mostly embedded in gangue minerals in an irregular granular shape. The size of chalcopyrite is generally 0.05 to 0.5 mm and the minimum is 0.001 mm.

Second, mineral processing technology research

(1) Determination of the beneficiation process

In addition to cassiterite, sulfide minerals and iron-bearing minerals, the ore mineral composition is a lower density gangue mineral with a content of 94.2%. The tin minerals dissociated later, until the -0.125+0.074mm particle size, the monomer dissociation rate reached 50%, and the continuous body 95% and gangue continuous. In order to re-elect the tail to pre-enrich the tin, it is advisable to adopt a stage grinding process and a stage selection process. Combined with the current economic value of the molybdenum market, the flotation of sulfide ore should be based on molybdenum. Therefore, the principle process of this test is determined by re-election, supplemented by other mineral processing methods, using stage grinding, stage sorting, mud sand sorting, medium mine separate treatment, fine mud returning, centralized sorting, sulfide ore recovery, tin Molybdenum is the beneficiation process for the main recovery target.

(2) Pre-selection test

In order to provide the necessary process conditions and configuration for the process test, pre-selection test work is the necessary condition for the process test to be carried out smoothly.

1. Sulfide ore flotation test

After grinding, the sulfide ore is first floated, and the sulfur tailings recovers tin, which is beneficial to the centralized recovery of metal sulfide ore such as molybdenum, copper and bismuth. In addition, molybdenum dissociation is earlier than tin, and it is reasonable to first float molybdenum ore. In the sulphide ore flotation, the effect of molybdenum recovery is evaluated. The test results show that the fineness of the flotation of the sulfide ore is preferably -0.074mm 60%.

2, spiral chute test

In the ore test, the spiral chute and the shaker were mainly investigated. The rough selection adopts a spiral chute. In order to avoid the iron pollution affecting the recovery of the spiral chute concentrate, the weak magnetic separation is used to remove the iron in the spiral chute concentrate and then perform the selection operation. The selection uses a shaker to give it the superiority of its high precision. The test results show that the spiral chute concentrate can be selected by the shaker at one time to obtain the classification index of 57.14% tin concentrate and 70.34% recovery rate. In addition to the overflow, for the selected tailings with a yield of 77.44% and a tin grade of 0.47%, another selection operation is added. The enrichment ratio of the concentrate products is only 4 times, and nearly 90% of the tailings tin grade is 0.28. %, can not be tailed, indicating that it is mainly poor. Therefore, it has the effect of adding selected operators to the selected tailings with 0.47% tin. Must be re-selected. When the shaker was selected, it was found that the coarse ore particles of the secondary concentrate belt were mixed with coarse veins, which affected the grade improvement of the secondary concentrate. After removing the secondary concentrate from +0.074mm, the 0.074mm fraction can be sorted by shaker once again, and a good index of 45.7% tin concentrate and 9329% recovery rate can be obtained, indicating that the secondary concentrate is selected. Effective.

3. Middle mine treatment

The medium ore mine is a combination of tailings and spiral chutes in the selection of spiral chute concentrates. The materials are directly selected, ground, and graded by grinding. The test results show that the selection effect after the middle ore grinding is obviously improved, and re-grinding is necessary. The results of the re-grinding test of the poor ore mine show that regardless of the grinding fineness -0.074mm, what is the difference between the selected ore grades, as long as the +0.074mm fraction is removed, the -0.074mm fraction can be obtained. High grade tin

The difference between the products is that the distribution of tin metal in the product is related to the content of -0.074mm after grinding, and the recovery rate increases with the increase of fineness. It can be seen that for the middle mine, the classification after fine grinding is the key to obtaining good indicators.

4, fine mud treatment

The fine mud treatment sample is a total overflow composed of a spiral chute overflow, a selected overflow, and a medium ore re-grinding overflow. Since the +0.02mm fraction of the fine mud is dominant, the amount of metal is about 70%. This dominant fraction is the optional fractional range of the flotation and centrifugal concentrator. It is difficult to obtain the products that meet the requirements for the direct flotation of fine mud, and the flotation concentrate contains more low-density gangue such as quartz, topaz and fluorite. Therefore, the fine mud treatment adopts the flotation tailing pre-enrichment process. Centrifuge re-election to improve the concentrate grade and discharge low-density gangue.

(III) Process test and results

1. Molybdenum and copper recovery test

The ore grinding fineness and sulfide ore flotation conditions are selected by pre-selection test, and the sulfide ore flotation test is carried out on this basis. Molybdenum selected tailings + sulfur concentrate 2 was selected by shaker to investigate the possibility of copper and antimony recovery. The process flow of the sulfide ore test is shown in Figure 1. The results of the closed-loop test of molybdenum flotation are shown in Table 3. The results of the test for the selection of bismuth and copper shakers are shown in Table 4. The results of multi-element analysis of molybdenum concentrates are shown in Table 5. The results of the recovery test of molybdenum and bismuth copper show that the molybdenum concentrate containing 47.22% of molybdenum and 90.58% of operation recovery can be obtained by separation and separation. The antimony concentrate containing bismuth 24.88% and the recovery rate of operation is 60.88% and the copper content is 12.76%. A copper concentrate with a recovery rate of 63.59%. It can be seen from Table 5 that the molybdenum concentrate meets the requirements of Class 2 to Class 3 products.

Figure 1 Sulfur ore beneficiation process

Table 3 Closed circuit test results of molybdenum circuit /%

Table 4 Tantalum shaker selection test results /%

Table 5 Multi-element analysis results of molybdenum concentrate /%

2. Tin recovery test

According to the pre-selection test, the recovery of tin adopts the re-election-flotation-re-election process, the spiral chute-shaker is the main process of the ore, and the fine mud adopts the flotation-centrifugal concentrator-high frequency shaker combination process, tin recovery test. It is divided into several parts: rough selection, selection, medium-mine treatment, and fine mud selection. The process of tin re-election-flotation-re-election is shown in Figure 2. The results of tin-selection test are shown in Table 6. The results of multi-element analysis of tin concentrate are shown in Table 7.

Figure 2 Selective tin re-election - flotation - re-election process

Table 6 Tin circuit closed circuit test results /%

Table 7 Results of multi-element analysis of tin concentrates/%

The closed-circuit test results of the tin-selecting circuit show that the tin concentrate with 56.11% tin and 74.20% recovery and tin-concentrated concentrate with tin content of 16.03% and recovery rate of 6.10% were obtained by the above procedure. The comprehensive recovery rate of tin was 80.30%. Tin concentrates meet Class II and Class III products.

Third, the conclusion

(1) The original ore contains 0.66% tin and 0.023% molybdenum is the main recycling element. Copper and antimony can be considered for comprehensive recovery.

(2) First floating sulphide ore, sulfur tailings re-recycling tin program to adapt to ore properties, can obtain 56.11% tin, recovery rate of 74.20% tin concentrate and molybdenum concentrate containing 47.22% molybdenum and recovery rate of 67.65%. Copper concentrates and antimony concentrates also meet the requirements of commodity grade concentrates, but only the test results are examined and further research is needed.

(3) The tin-re-election-flotation-re-election process scheme determined in this experiment is technically feasible and economically efficient. It has the following characteristics: the ore sand and fine mud recovery process form different combination processes; the silt sand sorting creates a stage for future production. The possibility of batch investment reflects the flexibility of the process; the spiral chute as a roughing device has a large processing capacity, the device itself has no power consumption, and has the function of sorting and grading “one machine multi-energy”; The selection of fine mud is easy to enlarge, the process is simple, and it is easy to control.

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