Method for discarding tailings before separation of low-grade molybdenum ore

Abstract

The invention provides a method for discarding tailings before separation of low-grade molybdenum ore. The method comprises a coarse crushing separation process and a fine crushing process, the intermediate ore is conveyed to an intelligent sorting machine to be sorted, rough concentrate and rough tailings are obtained, the rough tailings are subjected to secondary grading through a multi-layer screen, and dry separation tailings with different particle sizes are obtained; a wet-type tailing discarding procedure: performing primary slurry making on the rough concentrate and the undersize ore, conveying the slurry into a ball mill for ore grinding, performing secondary slurry making on an ore grinding product, and performing third-time grading through a cyclone to obtain fine-grain overflow slurry and coarse-grain underflow; a collecting agent is added into the coarse-grain underflow, coarse-grain flotation is conducted, coarse-grain concentrate and coarse-grain tailings are obtained, the coarse-grain concentrate returns to the ball mill, and coarse sand and tailings are obtained after the coarse-grain tailings are classified for the fourth time; and carrying out molybdenum flotation by taking the fine particle overflow pulp as flotation feed ore to obtain molybdenum concentrate. According to the method, efficient pre-separation tailing discarding of the low-grade molybdenum ore is achieved, the solid waste amount is greatly reduced, and the resource utilization rate of the molybdenum ore is increased.

Description

Technical Field

[0001] The present application relates to the technical field of molybdenum ore dressing, and in particular to a method for discarding tailings before dressing of low-grade molybdenum ore. Background Art

[0002] Molybdenum has the characteristics of high strength, high hardness, and excellent mechanical properties, and it can still maintain high strength and hardness at high temperatures. Molybdenum is mainly used in steelmaking. Alloy steel mixed with molybdenum has high strength, high toughness, outstanding heat resistance and corrosion resistance. Metal molybdenum is widely used in electronic devices such as electron tubes, transistors, rectifiers, etc.

[0003] Molybdenum mainly exists in the form of oxides or sulfides. The main naturally occurring molybdenum compounds are molybdenite, wolframite, ferromolybdenum and magnesia. With continuous mining and utilization, mineral resources tend to be poor, fine, mixed and difficult, and most molybdenum ores are already low-grade molybdenum ores.

[0004] At present, most molybdenum ore is crushed and pre-selected, non-metallic tailings are discarded, and the concentrate is selected by flotation. Low-grade molybdenum ore greatly increases the difficulty of beneficiation during the beneficiation process, which easily leads to a small amount of pre-selection tailings, resulting in a large amount of subsequent grinding and low grade, and at the same time increases the energy consumption of grinding and flotation, increasing production costs. At the same time, low-grade molybdenum ore leads to a large increase in the production of non-metallic tailings and a large amount of solid waste. If these tailings are directly piled up, it is easy to cause environmental pollution. Summary of the invention

[0005] The present application provides a method for discarding tailings before beneficiation of low-grade molybdenum ore, which is used to solve the above-mentioned problems mentioned in the background technology.

[0006] The present application provides a method for discarding tailings before beneficiation of low-grade molybdenum ore, the method comprising: (1) Coarse crushing and sorting process: After the molybdenum ore is coarsely crushed and medium crushed, it is first classified through a double-layer screen to obtain the oversize ore, intermediate ore and undersize ore; (2) Fine crushing process: the ore on the screen is finely crushed and then returned to the first classification process; (3) Dry tailings discarding process: The intermediate ore is transported to the intelligent sorting machine for sorting to obtain coarse concentrate and coarse tailings. The coarse tailings are classified for the second time through a multi-layer screen to obtain dry tailings with different particle sizes; (4) Wet tailings discarding process: The coarse concentrate and the undersize ore are slurried once and then transported to the ball mill for grinding. After the grinding product is slurried twice, it is classified for the third time through the cyclone to obtain fine-grained overflow slurry and coarse-grained underflow; Collectors are added to the coarse particle underflow, and coarse particle flotation is performed to obtain coarse particle concentrate and coarse particle tailings. The coarse particle concentrate is returned to the ball mill, and the coarse particle tailings are classified for the fourth time to obtain coarse sand and tailings. The fine-grained overflow slurry is used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0007] Optionally, the particle size of the ore after coarse crushing is ≤300mm, the particle size of the ore after medium crushing is ≤150mm, and the particle size of the ore after fine crushing is ≤60mm.

[0008] Optionally, the first classification process uses a double-layer sieve with an upper sieve hole diameter of 30 mm and a lower sieve hole diameter of 5 mm.

[0009] Optionally, the second classification uses a multi-layer sieve with a top sieve hole diameter of 20 mm, a middle sieve hole diameter of 10 mm, and a bottom sieve hole diameter of 3 mm.

[0010] Optionally, the dry-selected tailings include gravel 1 with a particle size of 20-30 mm, gravel 2 with a particle size of 10-20 mm, gravel 3 with a particle size of 3-10 mm, and stone powder with a particle size ≤3 mm.

[0011] Optionally, the method further comprises: conveying the coarse concentrate to a high pressure roller mill for re-crushing, and then performing a fifth classification through a sieve with a mesh diameter of 3 mm to obtain the coarse concentrate on the sieve and convey it back to the high pressure roller mill, slurrying the coarse concentrate under the sieve with the ore under the sieve, and conveying them to a ball mill for grinding.

[0012] Optionally, the fineness requirement of the material entering the ball mill is -3mm≥70wt%, and the grinding concentration entering the ball mill after the first slurry making is 65-68wt%.

[0013] Optionally, the feed concentration entering the cyclone after secondary slurrying is 30-35wt%, the fineness requirement of the fine-grained overflow slurry is -200 mesh content ≥40wt%, and the fineness requirement of the coarse-grained underflow is -200 mesh content ≤5wt%.

[0014] Optionally, coarse particles are flotated using a hydraulic flotation machine with a rising water flow rate of 5-8L / min and an aeration volume of 0.8-1m³ / min.

[0015] Optionally, the collector and its usage are 150-200g / t for mixed oil and 20-30g / t for No. 2 oil; The mixed oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1.

[0016] The method for discarding tailings before beneficiation of low-grade molybdenum ore provided in the present application realizes efficient discarding of tailings before beneficiation of low-grade molybdenum ore, and has the following beneficial effects compared with the prior art: (1) By combining the dry tailings discarding process with the wet tailings discarding process, the molybdenum ore is pre-discarded before the molybdenum flotation process, so that some low-grade ore or gangue is discarded in advance, and the amount of pre-selection tailings discarded is increased, thereby improving the grade of the molybdenum flotation feed and the recovery rate of molybdenum after molybdenum flotation. At the same time, it can reduce the processing load in the molybdenum flotation process, save energy consumption in the molybdenum flotation process, reduce production costs, and reduce waste liquid discharge in the molybdenum flotation process, thereby achieving the purpose of reducing costs and increasing efficiency.

[0017] (2) The dry tailings obtained from the dry tailings disposal process and the coarse sand obtained from the wet tailings disposal process can be used for building materials, achieving a raw ore product conversion rate of more than 95%. This not only realizes the resource utilization of tailings, but also solves the long-term and large-scale direct stacking of solid waste, avoids pollution to the surrounding environment, brings economic income to mining companies, and reduces the production costs of construction companies, with good economic and environmental benefits.

[0018] (3) The method for discarding tailings before selection provided in the present application has a simple process and is easy to operate, making the process of discarding tailings before selection of low-grade molybdenum ore more efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 A process diagram of a method for discarding tailings before beneficiation of low-grade molybdenum ore provided in one embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0022] The present application provides a method for discarding tailings before beneficiation of low-grade molybdenum ore, the method comprising: (1) Coarse crushing and sorting process: After the molybdenum ore is coarsely crushed and medium crushed, it is subjected to the first classification process through a double-layer screen to obtain the oversize ore, intermediate ore and undersize ore; (2) Fine crushing process: the ore on the screen is finely crushed and then returned to the first classification; (3) Dry tailings discarding process: The intermediate ore is transported to the intelligent sorting machine for sorting to obtain coarse concentrate and coarse tailings. The coarse tailings are classified for the second time through a multi-layer screen to obtain dry tailings with different particle sizes; (4) Wet tailings discarding process: The coarse concentrate and the undersize ore are slurried once and then transported to the ball mill for grinding. After the grinding product is slurried twice, it is classified for the third time through the cyclone to obtain fine-grained overflow slurry and coarse-grained underflow; Collectors are added to the coarse particle underflow, and coarse particle flotation is performed to obtain coarse particle concentrate and coarse particle tailings. The coarse particle concentrate is returned to the ball mill, and the coarse particle tailings are classified for the fourth time to obtain coarse sand and tailings. The fine-grained overflow slurry is used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0023] Specifically, the molybdenum ore is crushed through a coarse crushing and sorting process to obtain small particles of ore, and then the molybdenum ore is classified according to different particle sizes through a double-layer screen. The ore on the screen is input into a fine crushing process for further crushing. The purpose of this step is to crush the ore into a particle size suitable for the dry tailings disposal process, so as to facilitate the subsequent separation of non-metallic tailings and molybdenum ore.

[0024] The intermediate ore is transported to the intelligent sorting machine for sorting. The obtained rough tailings are classified for the second time through the multi-layer screen to obtain dry tailings with different particle sizes. This operation not only separates the non-metallic tailings from the molybdenum ore and achieves the purpose of dry tailings disposal, but also can pre-dispose the tailings before molybdenum flotation, reducing the amount of molybdenum ore entering the molybdenum flotation process, reducing the load of the molybdenum flotation process, reducing resource consumption, reducing the cost of molybdenum flotation, and also can improve the grade of the flotation feed entering the molybdenum flotation process and improve the efficiency of molybdenum flotation. Among them, the molybdenum grade of the intelligently sorted rough tailings is ≤0.02%.

[0025] The coarse concentrate obtained from the dry tailings disposal process and the undersize ore obtained from the coarse crushing and sorting process are pulped once and transported to a ball mill for grinding. The particle size of the molybdenum ore is further reduced by impact and grinding, thereby increasing the dissociation degree of molybdenum metal, which helps to improve the recovery rate of molybdenum in the subsequent molybdenum flotation process. By adding water to the coarse concentrate and the undersize ore for pulping once and then ball milling, it is beneficial to improve the ball milling efficiency. After the grinding product is pulped twice, it is classified for the third time through a cyclone to obtain fine-grained overflow slurry and coarse-grained underflow. The fine-grained overflow slurry is used as flotation feed for molybdenum flotation to obtain a high-grade molybdenum concentrate, which is used for subsequent molybdenum extraction.

[0026] Collectors are added to the coarse-grained underflow, and coarse-grained flotation is performed to obtain coarse-grained concentrate and coarse-grained tailings. By adding collectors, the collectors can be selectively adsorbed on the surface of molybdenum ore particles, enhancing their hydrophobicity, making it easier for molybdenum ore particles to adhere to bubbles and float up, and finally forming a mineralized foam layer, thereby separating molybdenum ore from tailings to obtain coarse-grained concentrate and coarse-grained tailings. The coarse-grained concentrate is returned to the ball mill for re-grinding, and then enters the third classification. The coarse-grained tailings are obtained by the fourth classification to obtain coarse sand and tailings, realizing wet tailings of coarse sand and tailings, and at the same time realizing further separation of molybdenum ore and non-metallic ore, and increasing the pre-selected tailings, improving the grade of molybdenum flotation feed, and thus improving the recovery rate of molybdenum. Coarse-grained flotation makes the grade of coarse tailings ≤0.015%, so as to ensure the grade of molybdenum flotation feed and improve the recovery rate of molybdenum. The mesh size of the fourth classification is 0.5mm, and the modulus of coarse sand is 3.2-3.5.

[0027] Furthermore, the molybdenum flotation process adopts the first concentration, the second concentration and the first scavenging. The equipment for the first concentration and the second concentration is the flotation column, and the equipment for the scavenging is the flotation machine. The grinding medium in the ball mill adopts wear-resistant ceramic balls, which can avoid the influence of iron addition on the taste of molybdenum ore when using steel balls.

[0028] By combining the dry tailing discarding process and the wet tailing discarding process, the molybdenum ore is pre-discarded before the molybdenum flotation process, and some low-grade ores or gangue are discarded in advance, thereby improving the grade of the molybdenum flotation feed, and improving the recovery rate of molybdenum after molybdenum flotation. At the same time, it can reduce the processing load in the molybdenum flotation process, save energy consumption in the molybdenum flotation process, reduce production costs, and reduce waste liquid discharge in the molybdenum flotation process, thereby achieving the purpose of reducing costs and increasing efficiency. At the same time, the pre-selection tailing discarding method provided by the present application is simple in process and easy to operate, making the pre-selection tailing discarding process of low-grade molybdenum ore more efficient.

[0029] Furthermore, the dry tailings obtained from the dry tailings disposal process and the coarse sand obtained from the wet tailings disposal process can both be used for building materials, and the dry tailings and coarse sand have different particle size specifications, such as being able to be used to replace sand and gravel aggregates in concrete, and can also be used in the production of road paving materials and building bricks. This not only realizes the resource utilization of tailings, solves the long-term and large-scale direct stacking of solid waste, avoids pollution to the surrounding environment, brings economic income to mining companies, and reduces the production costs of construction companies, with very good economic and environmental benefits.

[0030] The present application realizes the pre-selection tailings of low-grade molybdenum ore through the above scheme. By combining the dry tailings discarding process and the wet tailings discarding process, the molybdenum ore is pre-selected before the molybdenum flotation process, and some low-grade ores or gangue are discarded in advance, and the amount of pre-selected tailings discarded is increased, thereby improving the grade of the molybdenum flotation feed, and improving the recovery rate of molybdenum after molybdenum flotation. At the same time, it can reduce the processing load in the molybdenum flotation process, save energy consumption in the molybdenum flotation process, reduce production costs, and reduce waste liquid discharge in the molybdenum flotation process, achieving the purpose of reducing costs and increasing efficiency. At the same time, the dry tailings obtained by the dry tailings discarding process and the coarse sand obtained by the wet tailings discarding process can be used for building materials, which not only realizes the resource utilization of tailings, but also solves the long-term and large-scale direct stacking of solid waste, avoids pollution to the surrounding environment, brings economic income to the mining and selection enterprises, and reduces the production costs of construction enterprises, with good economic and environmental benefits.

[0031] Optionally, the particle size of the ore after coarse crushing is ≤300mm, the particle size of the ore after medium crushing is ≤150mm, and the particle size of the ore after fine crushing is ≤60mm.

[0032] Optionally, the first classification process uses a double-layer sieve with an upper sieve hole diameter of 30 mm and a lower sieve hole diameter of 5 mm.

[0033] Specifically, by subjecting the molybdenum ore to coarse, medium and fine crushing, the ore of different particle sizes can be obtained through screening, which can help to pre-discard the low-grade, non-molybdenum ore in the subsequent tailings discarding process, thereby facilitating the efficient flotation of molybdenum and improving the recovery rate of molybdenum. Among them, the medium crushing adopts a cone crusher.

[0034] Optionally, the second classification uses a multi-layer sieve with a top sieve hole diameter of 20 mm, a middle sieve hole diameter of 10 mm, and a bottom sieve hole diameter of 3 mm.

[0035] Optionally, the dry-selected tailings include gravel 1 with a particle size of 20-30 mm, gravel 2 with a particle size of 10-20 mm, gravel 3 with a particle size of 3-10 mm, and stone powder with a particle size ≤3 mm.

[0036] Specifically, the dry-selected tailings are classified for the second time and screened with a three-layer screen to obtain gravel of different particle sizes. In this way, when the dry-selected tailings are used for building materials, they can be selected according to the different specifications of the gravel, thereby improving the resource utilization rate of the gravel tailings, bringing better economic benefits to the enterprise, and reducing the emission of solid waste, with better environmental benefits.

[0037] like Figure 1As shown, optionally, the method also includes: after the coarse concentrate is transported to the high pressure roller mill for re-crushing, it is classified for the fifth time through a sieve with a mesh diameter of 3 mm, the coarse concentrate on the screen is transported back to the high pressure roller mill, the coarse concentrate under the screen is slurried with the under-screen ore, and the ore is transported to the ball mill for grinding.

[0038] Specifically, the coarse concentrate is crushed again by a high-pressure roller mill and then transported to a ball mill for grinding with the undersize ore. The particle size of the molybdenum ore entering the ball mill is further reduced by the high-pressure roller mill. This not only helps to increase the dissociation degree of molybdenum metal, but also improves the grinding efficiency of the ball mill, thereby helping to increase the subsequent molybdenum recovery rate.

[0039] Optionally, the material fineness requirement entering the ball mill is -3mm≥70wt%, and the grinding concentration entering the ball mill after the first slurrying is 65-68wt%. This can improve the grinding efficiency of the ball mill and help improve the dissociation degree of molybdenum metal.

[0040] Optionally, the feed concentration entering the cyclone after secondary slurrying is 30-35wt%, the fineness requirement of the fine-grained overflow slurry is -200 mesh content ≥40wt%, and the fineness requirement of the coarse-grained underflow is -200 mesh content ≤5wt%.

[0041] Specifically, ensuring that the feed concentration of the hydrocyclone is 30-35wt% is helpful for the separation efficiency of the hydrocyclone, and for the efficient separation of fine-grained overflow slurry and coarse-grained underflow, significantly reducing the number of repeated grindings in the ball mill, making the process of discarding tailings before molybdenum ore selection simpler and more efficient. Among them, the hydrocyclone classification pressure is 0.045-0.055Mpa.

[0042] Optionally, coarse particles are flotated using a hydraulic flotation machine with a rising water flow rate of 5-8L / min and an aeration volume of 0.8-1m³ / min.

[0043] Specifically, the change of the rising water flow rate will affect the pulp flow rate, flow state and shear force inside the pulp. When the rising water flow rate is too large, it is easy to cause a vascular flow state, which is easy to cause local unevenness in the mass transfer and flotation process; when the flow rate is too small, mineral loss, bubble imbalance and poor flotation effect may occur. At the same time, the appropriate rising water flow rate can ensure that the coarse-grained bottom flow stays long enough after entering the flotation machine, which helps to evenly distribute the bubbles and thus improve the flotation efficiency. At the same time, ensuring the appropriate amount of inflation is conducive to the uniformity of the size and density of the bubbles in the flotation machine during the flotation process, improving the selectivity of the bubbles, avoiding the waste of valuable molybdenum ore, improving the flotation efficiency, and thus improving the recovery rate of molybdenum.

[0044] The concentration of coarse particle underflow entering the coarse particle flotation is 35-45wt%, which, in combination with the rising water flow and aeration volume, provides suitable conditions for coarse particle flotation and improves the efficiency of coarse particle flotation. Optionally, the collector and its usage are 150-200g / t for mixed oil and 20-30g / t for No. 2 oil; The mixed oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1.

[0045] Specifically, No. 2 oil is mainly used as a frother to increase the hydrophobicity difference between mineral particles and promote the adhesion of minerals on bubbles. During the flotation process, No. 2 oil can generate bubbles of uniform size, suitable viscosity and stability, which are helpful for the separation of hydrophobic mineral particles and hydrophilic mineral particles. By mixing diesel and kerosene at a weight ratio of 4:1, the hydrophobicity of the mineral surface can be increased, the flotation efficiency can be improved, and then it can help to improve the flotation of molybdenum-containing ore particles in the wet tailing process, thereby improving the tailing efficiency, improving the taste of molybdenum flotation feed, and thus improving the recovery rate of molybdenum.

[0046] The following are embodiments of the present invention and effect test examples, and the technical scheme and technical effect of the present invention are further described, but the protection scope of the present invention is not limited to these embodiments. Any changes or equivalent substitutions that do not deviate from the concept of the present invention are within the protection scope of the present invention. In addition, those who do not indicate specific technical operation steps or conditions in the embodiments are all carried out according to the technology or conditions described in the general literature in this area or according to the product specification. Those who do not indicate the manufacturer of the reagents or instruments used are all conventional products that can be obtained commercially.

[0047] Example 1 A method for discarding tailings before selecting low-grade molybdenum ore, the method comprising the following steps: (1) Coarse crushing and sorting process: After the low-grade molybdenum ore with a molybdenum grade of 0.0874% is coarsely crushed and medium crushed, it is subjected to the first classification process through a double-layer screen to obtain the oversize ore, intermediate ore and undersize ore; (2) Fine crushing process: the ore on the screen is finely crushed and then returned to the first classification; The first classification process uses a double-layer sieve with an upper sieve hole diameter of 30 mm and a lower sieve hole diameter of 5 mm.

[0048] (3) Dry tailings discarding process: The intermediate ore is transported to the intelligent sorting machine for sorting to obtain coarse concentrate and coarse tailings. The coarse tailings are classified for the second time through a multi-layer screen to obtain dry tailings with different particle sizes; The second classification uses a multi-layer sieve with a top sieve hole diameter of 20mm, a middle sieve hole diameter of 10mm, and a bottom sieve hole diameter of 3mm. The resulting dry-selected tailings include gravel 1 with a particle size of 20-30mm, gravel 2 with a particle size of 10-20mm, gravel 3 with a particle size of 3-10mm, and stone powder with a particle size ≤3mm.

[0049] (4) Wet tailings discarding process: The coarse concentrate is sent to the high-pressure roller mill for re-crushing, and then is classified for the fifth time through a sieve with a mesh diameter of 3 mm. The coarse concentrate on the screen is sent back to the high-pressure roller mill. The coarse concentrate under the screen and the under-screen ore are slurried once and sent to the ball mill for grinding. The grinding product is slurried for the second time and then classified for the third time through a cyclone to obtain fine-grained overflow slurry and coarse-grained underflow; The fineness requirement of the material entering the ball mill is -3mm accounting for 70wt%, the grinding concentration entering the ball mill after the first slurrying is 65wt%, the feeding concentration entering the cyclone after the second slurrying is 30wt%, the fineness requirement of the fine-grained overflow slurry is -200 mesh accounting for 40wt%, and the fineness requirement of the coarse-grained underflow is -200 mesh accounting for 5wt%. Collectors are added to the coarse-grained underflow, and coarse-grained flotation is performed to obtain coarse-grained concentrate and coarse-grained tailings. The coarse-grained concentrate is returned to the ball mill, and the coarse-grained tailings are classified for the fourth time to obtain coarse sand and tailings; the coarse-grained flotation uses a hydraulic flotation machine, with an upward water flow of 5L / min and an aeration volume of 0.8m³ / min. The collector and its usage are 150g / t for mixed oil and 20g / t for No. 2 oil; the mixed oil is a mixture of diesel and kerosene at a weight ratio of 4:1.

[0050] In this embodiment, the early tailings discarding yield ((dry tailings mass + coarse tailings mass) / original ore mass) reaches 22.81%, and the gravel 1, gravel 2, gravel 2, stone powder obtained in the dry tailings discarding process and the coarse sand obtained in the wet tailings discarding process can all be used for building materials. The fine-grained overflow slurry is used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0051] The yield, molybdenum grade and molybdenum recovery rate of the molybdenum ore and the final tailings are summarized in Table 1. The results are shown in the following table.

[0052] Table 1 Weight / t Yield / % Molybdenum grade / % Molybdenum recovery rate / % Ore 108 100.00 0.0874 100.00 Stone 1 3.93 3.64 0.0157 0.65 Stone 2 4.47 4.14 0.0186 0.88 Stone 3 6.31 5.84 0.0132 0.88 Stone powder 4.83 4.47 0.0221 1.13 coarse sand 3.24 3.00 0.0113 0.39 Tailings 1.85 1.71 0.0185 0.36 Flotation feed 83.37 77.19 0.1084 95.70 Example 2 A method for discarding tailings before selecting low-grade molybdenum ore, the method comprising the following steps: (1) Coarse crushing and sorting process: After coarse crushing and medium crushing of low-grade molybdenum ore with a molybdenum grade of 0.0924%, the ore is subjected to the first classification process through a double-layer screen to obtain oversize ore, intermediate ore and undersize ore; (2) Fine crushing process: the ore on the screen is finely crushed and then returned to the first classification; The first classification process uses a double-layer sieve with an upper sieve hole diameter of 30 mm and a lower sieve hole diameter of 5 mm.

[0053] (3) Dry tailings discarding process: The intermediate ore is transported to the intelligent sorting machine for sorting to obtain coarse concentrate and coarse tailings. The coarse tailings are classified for the second time through a multi-layer screen to obtain dry tailings with different particle sizes; The second classification uses a multi-layer sieve with a top sieve hole diameter of 20mm, a middle sieve hole diameter of 10mm, and a bottom sieve hole diameter of 3mm. The resulting dry-selected tailings include stone 1 with a particle size of 20-30mm, stone 2 with a particle size of 10-20mm, stone 3 with a particle size of 3-10mm, and stone powder with a particle size of ≤3mm; (4) Wet tailings discarding process: The coarse concentrate is sent to the high-pressure roller mill for re-crushing, and then is classified for the fifth time through a sieve with a mesh diameter of 3 mm. The coarse concentrate on the screen is sent back to the high-pressure roller mill. The coarse concentrate under the screen and the under-screen ore are slurried once and sent to the ball mill for grinding. The grinding product is slurried for the second time and then classified for the third time through a cyclone to obtain fine-grained overflow slurry and coarse-grained underflow; The fineness requirement of the material entering the ball mill is -3mm accounting for 86wt%, the grinding concentration entering the ball mill after the first slurrying is 66wt%, the feed concentration entering the cyclone after the second slurrying is 33wt%, the fineness requirement of the fine-grained overflow slurry is -200 mesh accounting for 46wt%, and the fineness requirement of the coarse-grained underflow is -200 mesh accounting for 3wt%; Collectors are added to the coarse particle underflow, and coarse particle flotation is performed to obtain coarse particle concentrate and coarse particle tailings. The coarse particle concentrate is returned to the ball mill, and the coarse particle tailings are classified for the fourth time to obtain coarse sand and tailings. The coarse particle flotation uses a hydraulic flotation machine, with an upward water flow rate of 7L / min and an aeration volume of 0.95m³ / min. The collector and its usage are 180g / t of mixed oil and 25g / t of No. 2 oil. The mixed oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1. In this embodiment, an early tailings discarding yield of 24.48% is achieved, and the gravel 1, gravel 2, gravel 2, stone powder obtained in the dry tailings discarding process and the coarse sand obtained in the wet tailings discarding process can all be used for building materials. The fine-grained overflow slurry is used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0054] The yield, molybdenum grade and molybdenum recovery rate of the molybdenum ore and the final tailings are summarized in Table 2. The results are shown in the following table.

[0055] Table 2 Weight / t Yield / % Molybdenum grade / % Molybdenum recovery rate / % Ore 86 100.00 0.0924 100.00 Stone 1 3.11 3.62 0.0163 0.64 Stone 2 4.07 4.73 0.0158 0.81 Stone 3 5.23 6.08 0.0139 0.91 Stone powder 4.16 4.84 0.0205 1.07 coarse sand 2.93 3.41 0.0109 0.40 Tailings 1.55 1.80 0.0176 0.34 Flotation feed 64.95 75.52 0.1172 95.82 Example 3 A method for discarding tailings before selecting low-grade molybdenum ore, the method comprising the following steps: (1) Coarse crushing and sorting process: After the low-grade molybdenum ore with a molybdenum grade of 0.0907% is coarsely crushed and medium crushed, it is subjected to the first classification process through a double-layer screen to obtain the oversize ore, intermediate ore and undersize ore; (2) Fine crushing process: the ore on the screen is finely crushed and then returned to the first classification; The first classification process uses a double-layer sieve with an upper sieve hole diameter of 30 mm and a lower sieve hole diameter of 5 mm.

[0056] (3) Dry tailings discarding process: The intermediate ore is transported to the intelligent sorting machine for sorting to obtain coarse concentrate and coarse tailings. The coarse tailings are classified for the second time through a multi-layer screen to obtain dry tailings with different particle sizes; The second classification uses a multi-layer sieve with a top sieve hole diameter of 20mm, a middle sieve hole diameter of 10mm, and a bottom sieve hole diameter of 3mm. The resulting dry-selected tailings include stone 1 with a particle size of 20-30mm, stone 2 with a particle size of 10-20mm, stone 3 with a particle size of 3-10mm, and stone powder with a particle size of ≤3mm; (4) Wet tailings discarding process: The coarse concentrate is sent to the high-pressure roller mill for re-crushing, and then is classified for the fifth time through a sieve with a mesh diameter of 3 mm. The coarse concentrate on the screen is sent back to the high-pressure roller mill. The coarse concentrate under the screen and the under-screen ore are slurried once and sent to the ball mill for grinding. The grinding product is slurried for the second time and then classified for the third time through a cyclone to obtain fine-grained overflow slurry and coarse-grained underflow; The fineness requirement of the material entering the ball mill is -3mm accounting for 82wt%, the grinding concentration entering the ball mill after the first slurrying is 68wt%, the feed concentration entering the cyclone after the second slurrying is 35wt%, the fineness requirement of the fine-grained overflow slurry is -200 mesh accounting for 52wt%, and the fineness requirement of the coarse-grained underflow is -200 mesh accounting for 2.7wt%; Collectors are added to the coarse-grained underflow, and coarse-grained flotation is performed to obtain coarse-grained concentrate and coarse-grained tailings. The coarse-grained concentrate is returned to the ball mill, and the coarse-grained tailings are classified for the fourth time to obtain coarse sand and tailings; the coarse-grained flotation uses a hydraulic flotation machine, with an upward water flow of 8L / min and an aeration volume of 1m³ / min. The collector and its usage are 200g / t for mixed oil and 30g / t for No. 2 oil; the mixed oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1.

[0057] The gravel 1, gravel 2, gravel 2, stone powder obtained in the dry tailings discarding process and the coarse sand obtained in the wet tailings discarding process can all be used for building materials, and the fine-grained overflow slurry is used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0058] The yield, molybdenum grade and molybdenum recovery rate of the molybdenum ore and the final tailings are summarized in Table 3. The results are shown in the following table.

[0059] Table 3 Weight / t Yield / % Molybdenum grade / % Molybdenum recovery rate / % Ore 92 100.00 0.0907 100.00 Stone 1 2.67 2.90 0.0153 0.49 Stone 2 3.78 4.11 0.0156 0.71 Stone 3 5.35 5.82 0.0129 0.83 Stone powder 4.28 4.65 0.0202 1.04 coarse sand 4.27 4.64 0.0114 0.58 Tailings 1.46 1.59 0.0163 0.27 Flotation feed 70.19 76.29 0.1132 95.21 Comparative Example 1 A method for discarding tailings before selecting low-grade molybdenum ore, the method comprising the following steps: (1) Coarse crushing and sorting process: 88 tons of low-grade molybdenum ore with a molybdenum grade of 0.0826% was coarsely crushed and medium crushed, and then passed through a sieve with a mesh diameter of 30 mm for the first classification process to obtain the oversize ore and undersize ore; (2) Fine crushing process: the ore on the screen is finely crushed and then returned to the first classification; (3) The ore under the screen is pulped once and then transported to a ball mill for grinding. The ground product is pulped twice and then classified for the third time by a hydrocyclone to obtain fine-grained overflow slurry and coarse-grained underflow; The material fineness requirement entering the ball mill is -3mm accounting for 82wt%, the grinding concentration entering the ball mill after the first slurrying is 68wt%, the feed concentration entering the cyclone after the second slurrying is 35wt%, the fineness requirement of the fine-grained overflow slurry is -200 mesh accounting for 52wt%, and the fineness requirement of the coarse-grained underflow is -200 mesh accounting for 2.7wt%; the coarse-grained underflow ore is returned to the ball mill, and the fine-grained overflow slurry is used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0060] The final molybdenum grade of the flotation feed was 0.0826%, and the molybdenum recovery rate was 62%.

[0061] By using the technical solutions of Examples 1 to 3 and Comparative Example 1, the low-grade molybdenum ore is subjected to pre-selection tailings discarding. In Examples 1 to 3, the molybdenum grade of the flotation feed is significantly improved, and the molybdenum recovery rate reaches more than 95%, indicating that by using the technical solution provided in the present application, a dry tailings discarding process and a wet tailings discarding process are combined to pre-discard the tailings of the molybdenum ore before the molybdenum flotation process, thereby improving the grade of the molybdenum flotation feed, and further improving the molybdenum recovery rate after the molybdenum flotation process.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for discarding tailings before selecting low-grade molybdenum ore, characterized in that: include: (1) Coarse crushing and sorting process: After the molybdenum ore is coarsely crushed and medium crushed, it is first classified through a double-layer screen to obtain the oversize ore, intermediate ore and undersize ore; (2) Fine crushing process: the ore on the screen is finely crushed and then returned to the first classification; (3) Dry tailings discarding process: the intermediate ore is transported to an intelligent sorting machine for sorting to obtain coarse concentrate and coarse tailings. The coarse tailings are subjected to a second classification through a multi-layer screen to obtain dry tailings with different particle sizes; (4) Wet tailings discarding process: the coarse concentrate and the undersize ore are slurried once, transported to a ball mill for grinding, the ground product is slurried twice, and then classified for the third time by a hydrocyclone to obtain a fine-grained overflow slurry and a coarse-grained underflow; Adding a collector to the coarse particle underflow and performing coarse particle flotation to obtain coarse particle concentrate and coarse particle tailings, wherein the coarse particle concentrate is returned to the ball mill, and the coarse particle tailings are subjected to a fourth classification to obtain coarse sand and tailings; The fine-grained overflow slurry is used as flotation feed to carry out molybdenum flotation to obtain molybdenum concentrate.

2. The method for discarding tailings before selecting low-grade molybdenum ore according to claim 1, wherein: The particle size of the ore discharged after the coarse crushing is ≤300mm, the particle size of the ore discharged after the medium crushing is ≤150mm, and the particle size of the ore discharged after the fine crushing is ≤60mm.

3. The method for discarding tailings before selecting low-grade molybdenum ore according to claim 1, characterized in that: The first classification process uses a double-layer sieve with an upper sieve hole diameter of 30 mm and a lower sieve hole diameter of 5 mm.

4. The method for discarding tailings before selecting low-grade molybdenum ore according to claim 1, characterized in that: The second classification has a multi-layer sieve with a top sieve hole diameter of 20 mm, a middle sieve hole diameter of 10 mm, and a bottom sieve hole diameter of 3 mm.

5. The method for discarding tailings before selecting low-grade molybdenum ore according to claim 1, characterized in that: The dry-selected tailings include gravel 1 with a particle size of 20-30 mm, gravel 2 with a particle size of 10-20 mm, gravel 3 with a particle size of 3-10 mm, and stone powder with a particle size of ≤3 mm.

6. The method for discarding tailings before selecting low-grade molybdenum ore according to claim 1, characterized in that: The method further comprises: conveying the coarse concentrate to a high pressure roller mill for re-crushing, performing a fifth classification through a sieve with a mesh diameter of 3 mm, obtaining an oversize coarse concentrate which is conveyed back to the high pressure roller mill, and slurrying the undersize coarse concentrate with the undersize ore, and conveying the ore to a ball mill for grinding.

7. The method for discarding tailings before selecting low-grade molybdenum ore according to claim 1, characterized in that: The material fineness requirement entering the ball mill is -3mm≥70wt%, and the grinding concentration entering the ball mill after one slurry making is 65-68wt%.

8. The method for discarding tailings before selecting low-grade molybdenum ore according to claim 1, characterized in that: The feed concentration of the ore entering the cyclone after the secondary slurrying is 30-35wt%, the fineness requirement of the fine-grained overflow slurry is -200 mesh content ≥40wt%, and the fineness requirement of the coarse-grained underflow is -200 mesh content ≤5wt%.

9. The method for discarding tailings before selecting low-grade molybdenum ore according to claim 1, characterized in that: The coarse particle flotation adopts a hydraulic flotation machine, the rising water flow rate is 5-8L / min, and the inflation volume is 0.8-1m³ / min.

10. The method for discarding tailings before beneficiation of low-grade molybdenum ore according to any one of claims 1 to 9, characterized in that: The collector and its usage are 150-200 g / t for mixed oil and 20-30 g / t for No. 2 oil; The mixed oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1.

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