Method for discarding tailings before low-grade molybdenum ore selection

Abstract

The application provides a low-grade molybdenum ore pre-concentration and tailing discarding method, which comprises the following steps: a coarse crushing and separation process, a fine crushing process, a dry tailing discarding process, an intermediate ore is fed into an intelligent separator to obtain coarse concentrate and coarse tailings, the coarse tailings are subjected to second classification through a multi-layer screen to obtain dry tailing discards with different particle sizes, a wet tailing discarding process, the coarse concentrate and undersize ore are subjected to first pulp making, and then are fed into a ball mill for grinding, the grinding product is subjected to second pulp making, and then is subjected to third classification through a cyclone to obtain fine particle overflow pulp and coarse particle underflow, a collector is added into the coarse particle underflow, and coarse particle flotation is carried out 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 subjected to fourth classification to obtain coarse sand and tailings, and the fine particle overflow pulp is used as flotation feed ore to carry out molybdenum flotation to obtain molybdenum concentrate. The application realizes efficient pre-concentration and tailing discarding of low-grade molybdenum ore, greatly reduces the solid waste amount, and improves the resource utilization rate of molybdenum ore.

Description

Technical Field

[0001] This application relates to the field of molybdenum ore beneficiation technology, and in particular to a method for pre-beneficiation tailings removal in low-grade molybdenum ore. Background Technology

[0002] Molybdenum possesses high strength, high hardness, and excellent mechanical properties, maintaining these characteristics even at high temperatures. It is primarily used in steelmaking; molybdenum-doped alloy steel exhibits high strength, high toughness, outstanding heat resistance, and corrosion resistance. Metallic molybdenum also has wide applications in electronic devices such as electron tubes, transistors, and rectifiers.

[0003] Molybdenum mainly exists in the form of oxides or sulfides. The main naturally occurring molybdenum compounds are molybdenite, tungsten-lead ore, iron-molybdenite, and magnesium-manganese ore. With continuous mining and utilization, mineral resources are trending towards being less valuable, finer, more complex, and more difficult to obtain, and most molybdenum ores are now classified as low-grade molybdenum ores.

[0004] Currently, molybdenum ore is typically crushed, pre-selected, and the non-metallic tailings are discarded. The concentrate is then processed using flotation. Low-grade molybdenum ore significantly increases the difficulty of beneficiation, often resulting in insufficient pre-selection tailings and consequently, a large and low-grade feed to the mill. This also increases energy consumption in grinding and flotation, raising production costs. Furthermore, low-grade molybdenum ore generates a large amount of non-metallic tailings and substantial solid waste; directly dumping these tailings could easily cause environmental pollution. Summary of the Invention

[0005] This application provides a method for pre-processing tailings removal in low-grade molybdenum ore to solve the problems mentioned in the background art.

[0006] This application provides a method for pre-beneficiation tailings removal in low-grade molybdenum ore, the method comprising:

[0007] (1) Coarse crushing and sorting process: After coarse and medium crushing, the raw molybdenum ore is first classified by double-layer screen to obtain oversize ore, intermediate ore and undersize ore;

[0008] (2) Fine crushing process: The ore on the screen is finely crushed and then returned to the first classification process;

[0009] (3) Dry tailings disposal process: The intermediate ore is transported to the intelligent separator for separation to obtain coarse concentrate and coarse tailings. The coarse tailings are then classified a second time through a multi-layer screen to obtain dry tailings with different particle sizes.

[0010] (4) Wet tailings disposal process: The rough concentrate and undersize ore are slurried once and then fed into a ball mill for grinding. The grinding product is slurried a second time and then classified a third time by a hydrocyclone to obtain fine overflow slurry and coarse underflow.

[0011] Collector is added to the coarse underflow and coarse flotation is performed to obtain coarse concentrate and coarse tailings. The coarse concentrate is returned to the ball mill and the coarse tailings are classified into coarse sand and tailings through a fourth classification.

[0012] Fine-grained overflow slurry was used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0013] Optionally, the particle size of the ore discharged after coarse crushing is ≤300mm, the particle size of the ore discharged after medium crushing is ≤150mm, and the particle size of the ore discharged after fine crushing is ≤60mm.

[0014] Optionally, the upper screen of the double-layer sieve used in the first grading process has a screen diameter of 30mm, and the lower screen has a screen diameter of 5mm.

[0015] Optionally, the second grading uses a multi-layer sieve with a top layer sieve hole diameter of 20mm, a middle layer sieve hole diameter of 10mm, and a bottom layer sieve hole diameter of 3mm.

[0016] Optionally, the dry 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 of ≤3mm.

[0017] Optionally, the method further includes: feeding the coarse concentrate to a high-pressure roller mill for further crushing, then performing a fifth classification through a sieve with a screen diameter of 3 mm to obtain the oversize coarse concentrate, which is then fed back to the high-pressure roller mill; and mixing the undersize coarse concentrate with the undersize ore to form a slurry, which is then fed to a ball mill for grinding.

[0018] Optionally, the fineness requirement of the material entering the ball mill is -3mm ≥ 70wt%, and the grinding concentration entering the ball mill after primary pulping is 65-68wt%.

[0019] Optionally, the feed concentration entering the hydrocyclone after secondary pulping is 30-35 wt%, the fineness requirement of the fine overflow slurry is ≥40 wt% of -200 mesh content, and the fineness requirement of the coarse underflow is ≤5 wt% of -200 mesh content.

[0020] Optionally, coarse flotation uses a hydraulic flotation machine with a rising water flow rate of 5-8 L / min and an aeration rate of 0.8-1 m³ / min.

[0021] Optionally, the collector and its dosage are 150-200g / t for mixed oil and 20-30g / t for No. 2 oil;

[0022] The blended oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1.

[0023] The method for pre-processing tailings removal in low-grade molybdenum ore provided in this application achieves efficient pre-processing tailings removal in low-grade molybdenum ore, and has the following advantages compared with the prior art:

[0024] (1) By combining dry tailings disposal process and wet tailings disposal process, the raw molybdenum ore is pre-discarded before the molybdenum flotation process, and some low-grade ore or gangue is discarded in advance, and the amount of pre-discarded tailings is increased, thereby improving the grade of the molybdenum flotation feed and the molybdenum recovery rate 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, reduce waste liquid discharge in the molybdenum flotation process, and achieve the purpose of cost reduction and efficiency improvement.

[0025] (2) Both 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 conversion rate of over 95% for the original mineral products. This not only realizes the resource utilization of tailings and solves the problem of long-term and large-scale direct dumping of solid waste, but also avoids pollution to the surrounding environment. It brings economic income to mining enterprises while reducing the production costs of construction enterprises, thus having good economic and environmental benefits.

[0026] (3) The pre-selection tailings removal method provided in this application has a simple process and is easy to operate, making the pre-selection tailings removal process of low-grade molybdenum ore more efficient. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a process diagram of a method for pre-processing and tailings removal of low-grade molybdenum ore provided in an embodiment of this application. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application are described clearly and completely below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are also within the scope of protection of this application.

[0030] This application provides a method for pre-beneficiation tailings removal in low-grade molybdenum ore, the method comprising:

[0031] (1) Coarse crushing and sorting process: After coarse and medium crushing, the raw molybdenum ore is first classified by double-layer screen to obtain oversize ore, intermediate ore and undersize ore;

[0032] (2) Fine crushing process: The ore on the screen is finely crushed and then returned to the first classification;

[0033] (3) Dry tailings disposal process: The intermediate ore is transported to the intelligent separator for separation to obtain coarse concentrate and coarse tailings. The coarse tailings are then classified a second time through a multi-layer screen to obtain dry tailings with different particle sizes.

[0034] (4) Wet tailings disposal process: The rough concentrate and undersize ore are slurried once and then fed into a ball mill for grinding. The grinding product is slurried a second time and then classified a third time by a hydrocyclone to obtain fine overflow slurry and coarse underflow.

[0035] Collector is added to the coarse underflow and coarse flotation is performed to obtain coarse concentrate and coarse tailings. The coarse concentrate is returned to the ball mill and the coarse tailings are classified into coarse sand and tailings through a fourth classification.

[0036] Fine-grained overflow slurry was used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0037] Specifically, the raw molybdenum ore is crushed through a coarse crushing and sorting process to obtain small particles of ore. Then, it undergoes a first classification process through a double-layer screen to classify the molybdenum ore according to different particle sizes. The ore that passes through the screen is then fed into a fine crushing process for further crushing. The purpose of this step is to crush the ore into particle sizes suitable for dry tailings disposal, so as to facilitate the subsequent separation of non-metallic tailings and molybdenum ore.

[0038] Intermediate ore is fed to an intelligent separator for sorting. The resulting coarse tailings are then subjected to a second classification using a multi-layer screen, yielding dry tailings of varying particle sizes. This process not only separates non-metallic tailings from molybdenum ore, achieving dry tailings disposal, but also pre-disposes the tailings before molybdenum flotation, reducing the amount of molybdenum ore entering the flotation process, lowering the load on the process, reducing resource consumption, and reducing flotation costs. It also improves the grade of the flotation feed entering the process, thus increasing flotation efficiency. Specifically, the molybdenum grade of the intelligently separated coarse tailings is ≤0.02%.

[0039] The rough concentrate from the dry tailings disposal process and the undersize ore from the coarse crushing and separation process are first pulped and then fed into a ball mill for grinding. The impact and abrasive action further reduces the particle size of the molybdenum ore, thereby increasing the liberation of molybdenum metal and improving the molybdenum recovery rate in subsequent molybdenum flotation. Adding water to the rough concentrate and undersize ore for the first pulping process before ball milling improves milling efficiency. After a second pulping, the grinding product undergoes a third classification using a hydrocyclone to obtain a fine overflow slurry and a coarse underflow. The fine overflow slurry is used as the flotation feed for molybdenum flotation, yielding a high-grade molybdenum concentrate, which is then used for subsequent molybdenum extraction.

[0040] A collector is added to the coarse-grained understream, followed by coarse-grained flotation to obtain coarse-grained concentrate and tailings. The collector selectively adsorbs onto the surface of molybdenum ore particles, enhancing their hydrophobicity and making them more easily adhere to bubbles and float, ultimately forming a mineralized froth layer. This separates the molybdenum ore from the tailings, yielding coarse-grained concentrate and tailings. The coarse-grained concentrate is returned to the ball mill for further grinding and then undergoes a third classification. The coarse-grained tailings are classified in a fourth stage to obtain coarse sand and tailings, achieving wet tailings disposal. This further separates molybdenum ore from non-metallic minerals, increases the amount of pre-disposal tailings, improves the grade of the molybdenum flotation feed, and thus enhances molybdenum recovery. Coarse-grained flotation ensures a coarse-grained tailings grade ≤0.015% to guarantee the grade of the molybdenum flotation feed and improve molybdenum recovery. The fourth classification uses a 0.5mm sieve with a coarse sand modulus of 3.2-3.5.

[0041] Furthermore, the molybdenum flotation process employs a first cleaning, a second cleaning, and a scavenging stage. The first and second cleaning stages are carried out using flotation columns, while the scavenging stage uses a flotation machine. The grinding media in the ball mill are wear-resistant ceramic balls, which avoids the impact of iron admixture on the molybdenum ore grade that would occur with steel balls.

[0042] By combining dry and wet tailings removal processes, pre-tailings removal is performed on the raw molybdenum ore before the molybdenum flotation process. This removes some low-grade ore or gangue in advance, thereby increasing the grade of the molybdenum flotation feed and improving the molybdenum recovery rate after flotation. Simultaneously, it reduces the processing load during molybdenum flotation, saves energy consumption, lowers production costs, and reduces wastewater discharge, achieving the goal of cost reduction and efficiency improvement. Furthermore, the pre-flotation tailings removal method provided in this application is simple to operate and makes the pre-flotation tailings removal process for low-grade molybdenum ore more efficient.

[0043] Furthermore, both the dry tailings obtained from the dry tailings disposal process and the coarse sand obtained from the wet tailings disposal process can be used in building materials. Moreover, the dry tailings and coarse sand have different particle size specifications. For example, they can be used to replace sand and gravel aggregates in concrete, as well as in the production of road paving materials and building bricks. This not only realizes the resource utilization of tailings and solves the problem of long-term and large-scale direct dumping of solid waste, avoiding pollution to the surrounding environment, but also brings economic income to mining and beneficiation enterprises while reducing the production costs of construction enterprises, thus having good economic and environmental benefits.

[0044] This application, through the aforementioned scheme, achieves pre-flotation tailings removal from low-grade molybdenum ore. By combining dry and wet tailings removal processes, the raw molybdenum ore undergoes pre-flotation tailings removal before the molybdenum flotation process, removing some low-grade ore or gangue in advance and increasing the amount of pre-removed tailings. This improves the grade of the molybdenum flotation feed and the molybdenum recovery rate after flotation. Simultaneously, it reduces the processing load during molybdenum flotation, saves energy consumption, lowers production costs, and reduces wastewater discharge, achieving cost reduction and efficiency improvement. Furthermore, both the dry tailings from the dry tailings removal process and the coarse sand from the wet tailings removal process can be used in building materials. This not only realizes the resource utilization of tailings and solves the problem of long-term, large-scale direct stockpiling of solid waste, avoiding pollution to the surrounding environment, but also brings economic benefits to mining and beneficiation enterprises while reducing production costs for construction companies, demonstrating significant economic and environmental benefits.

[0045] Optionally, the particle size of the ore discharged after coarse crushing is ≤300mm, the particle size of the ore discharged after medium crushing is ≤150mm, and the particle size of the ore discharged after fine crushing is ≤60mm.

[0046] Optionally, the upper screen of the double-layer sieve used in the first grading process has a screen diameter of 30mm, and the lower screen has a screen diameter of 5mm.

[0047] Specifically, by subjecting the raw molybdenum ore to multi-stage crushing (coarse, medium, and fine), and then screening it to obtain ore of different particle sizes, it is possible to pre-dispose of low-grade and non-molybdenum ores during the subsequent tailings disposal process. This, in turn, facilitates efficient molybdenum flotation and improves molybdenum recovery. The medium crushing stage utilizes a cone crusher.

[0048] Optionally, the second grading uses a multi-layer sieve with a top layer sieve hole diameter of 20mm, a middle layer sieve hole diameter of 10mm, and a bottom layer sieve hole diameter of 3mm.

[0049] Optionally, the dry 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 of ≤3mm.

[0050] Specifically, the dry tailings undergo a second classification and are screened using a three-layer screen to obtain stones of different sizes. When the dry tailings are used in building materials, they can be selected and matched according to different stone specifications, which improves the resource utilization rate of the stone tailings, brings better economic benefits to enterprises, and reduces solid waste emissions, thus having good environmental benefits.

[0051] like Figure 1As shown, optionally, the method further includes: feeding the coarse concentrate to a high-pressure roller mill for further crushing, then performing a fifth classification through a sieve with a screen diameter of 3 mm to obtain the coarse concentrate on the screen, which is then fed back to the high-pressure roller mill; the coarse concentrate and the undersize ore are mixed once and then fed to a ball mill for grinding.

[0052] Specifically, the rough concentrate is crushed again by a high-pressure roller mill and then fed with the undersize ore into a ball mill for grinding. The high-pressure roller mill further reduces the particle size of the molybdenum ore entering the ball mill, which not only helps to improve the degree of liberation of molybdenum metal, but also improves the grinding efficiency of the ball mill, thereby helping to improve the subsequent molybdenum recovery rate.

[0053] Optionally, the fineness of the material entering the ball mill should be -3mm ≥ 70wt%, and the grinding concentration entering the ball mill after the first slurry preparation should be 65-68wt%. This can improve the grinding efficiency of the ball mill and is beneficial to improving the degree of liberation of molybdenum metal.

[0054] Optionally, the feed concentration entering the hydrocyclone after secondary pulping is 30-35 wt%, the fineness requirement of the fine overflow slurry is ≥40 wt% of -200 mesh content, and the fineness requirement of the coarse underflow is ≤5 wt% of -200 mesh content.

[0055] Specifically, maintaining a feed concentration of 30-35 wt% in the hydrocyclone improves its separation efficiency, facilitates the efficient separation of fine-grained overflow slurry from coarse-grained underflow, significantly reduces the number of re-grinding operations in the ball mill, and simplifies and simplifies the pre-processing tailings removal of molybdenum ore. The hydrocyclone classification pressure is 0.045-0.055 MPa.

[0056] Optionally, coarse flotation uses a hydraulic flotation machine with a rising water flow rate of 5-8 L / min and an aeration rate of 0.8-1 m³ / min.

[0057] Specifically, changes in the upward water flow rate affect the pulp velocity, flow state, and internal shear force. Excessive upward water flow can create a vascular flow pattern, leading to localized inhomogeneities during mass transfer and flotation. Conversely, insufficient flow can result in mineral loss, bubble imbalance, and poor flotation performance. A suitable upward water flow rate ensures a sufficiently long residence time for coarse particles entering the flotation machine, promoting uniform bubble distribution and improving flotation efficiency. Furthermore, adequate aeration contributes to the uniformity of bubble size and density during flotation, improving selectivity, preventing the waste of valuable molybdenum ore, and ultimately increasing molybdenum recovery.

[0058] The concentration of coarse particles entering the coarse particle flotation stream is 35-45 wt%. This concentration, coordinated with the riser flow rate and aeration rate, provides suitable conditions for coarse particle flotation, thereby improving its efficiency.

[0059] Optionally, the collector and its dosage are 150-200g / t for mixed oil and 20-30g / t for No. 2 oil;

[0060] The blended oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1.

[0061] Specifically, No. 2 oil primarily functions as a frother, increasing the hydrophobicity difference between mineral particles and promoting mineral adhesion to air bubbles. During flotation, No. 2 oil generates uniformly sized, appropriately viscous, and stable bubbles, which facilitate the separation of hydrophobic and hydrophilic mineral particles. Mixing diesel and kerosene in a 4:1 weight ratio increases the hydrophobicity of mineral surfaces, improving flotation efficiency. This, in turn, enhances the flotation of molybdenum-containing ore particles in the wet tailings removal process, thereby increasing tailings removal efficiency, improving the grade of the molybdenum flotation feed, and ultimately increasing molybdenum recovery.

[0062] The following are embodiments and effect test examples of the present invention, further describing the technical solution and technical effects of the present invention. However, the scope of protection of the present invention is not limited to these embodiments. Any changes or equivalent substitutions that do not depart from the concept of the present invention are within the scope of protection of the present invention. Furthermore, for those embodiments where specific technical operation steps or conditions are not specified, they are performed according to the techniques or conditions described in general literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0063] Example 1

[0064] A method for pre-beneficiation tailings removal in low-grade molybdenum ore, comprising the following steps:

[0065] (1) Coarse crushing and sorting process: The low-grade molybdenum ore with a molybdenum grade of 0.0874% is coarsely crushed and then medium crushed, and then subjected to the first classification process through a double-layer screen to obtain the oversize ore, intermediate ore and undersize ore;

[0066] (2) Fine crushing process: The ore on the screen is finely crushed and then returned to the first classification;

[0067] The first grading process uses a double-layer sieve with an upper sieve aperture diameter of 30mm and a lower sieve aperture diameter of 5mm.

[0068] (3) Dry tailings disposal process: The intermediate ore is transported to the intelligent separator for separation to obtain coarse concentrate and coarse tailings. The coarse tailings are then classified a second time through a multi-layer screen to obtain dry tailings with different particle sizes.

[0069] The second classification uses a multi-layer sieve with a top sieve aperture diameter of 20 mm, a middle sieve aperture diameter of 10 mm, and a bottom sieve aperture diameter of 3 mm. The resulting dry 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.

[0070] (4) Wet tailings disposal process: After the coarse concentrate is fed to the high-pressure roller mill for further crushing, it is classified for the fifth time through a sieve with a screen diameter of 3mm. The coarse concentrate on the screen is fed back to the high-pressure roller mill. The coarse concentrate and the undersize ore are slurried once and fed to the ball mill for grinding. After the grinding product is slurried a second time, it is classified for the third time through a hydrocyclone to obtain fine overflow slurry and coarse underflow.

[0071] The required fineness of the material entering the ball mill is -3mm, accounting for 70wt%. After primary slurry preparation, the grinding concentration entering the ball mill is 65wt%. After secondary slurry preparation, the feed concentration entering the hydrocyclone is 30wt%. The fineness requirement for the fine overflow slurry is -200 mesh, accounting for 40wt%, and the fineness requirement for the coarse underflow slurry is -200 mesh, accounting for 5wt%.

[0072] Collector is 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 subjected to a fourth classification to obtain coarse sand and tailings. The coarse-grained flotation is carried out using a hydraulic flotation machine with a rising water flow rate of 5 L / min and an aeration rate of 0.8 m³ / min. The collector and its usage are as follows: 150 g / t of mixed oil and 20 g / t of No. 2 oil; the mixed oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1.

[0073] In this embodiment, the pre-disposal tailings yield ((dry tailings mass + coarse tailings mass) / raw ore mass) reaches 22.81%. The gravel 1, gravel 2, gravel 2, stone powder obtained from the dry tailings disposal process and the coarse sand obtained from the wet tailings disposal process can all be used for building materials. The fine overflow slurry is used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0074] The yield, molybdenum grade, and molybdenum recovery rate of the raw molybdenum ore and the final tailings are summarized in Table 1, and the results are shown in the table below.

[0075] Table 1

[0076] weight / t Yield / % Molybdenum grade / % Molybdenum recovery rate / % raw 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 3 stones 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

[0077] Example 2

[0078] A method for pre-beneficiation tailings removal in low-grade molybdenum ore, comprising the following steps:

[0079] (1) Coarse crushing and sorting process: The low-grade molybdenum ore with a molybdenum grade of 0.0924% is coarsely crushed and then medium crushed, and then subjected to the first classification process through a double-layer screen to obtain the oversize ore, intermediate ore and undersize ore;

[0080] (2) Fine crushing process: The ore on the screen is finely crushed and then returned to the first classification;

[0081] The first grading process uses a double-layer sieve with an upper sieve aperture diameter of 30mm and a lower sieve aperture diameter of 5mm.

[0082] (3) Dry tailings disposal process: The intermediate ore is transported to the intelligent separator for separation to obtain coarse concentrate and coarse tailings. The coarse tailings are then classified a second time through a multi-layer screen to obtain dry tailings with different particle sizes.

[0083] The second classification uses a multi-layer sieve with a top sieve aperture diameter of 20mm, a middle sieve aperture diameter of 10mm, and a bottom sieve aperture diameter of 3mm. The resulting dry 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 of ≤3mm.

[0084] (4) Wet tailings disposal process: After the coarse concentrate is fed to the high-pressure roller mill for further crushing, it is classified for the fifth time through a sieve with a screen diameter of 3mm. The coarse concentrate on the screen is fed back to the high-pressure roller mill. The coarse concentrate and the undersize ore are slurried once and fed to the ball mill for grinding. After the grinding product is slurried a second time, it is classified for the third time through a hydrocyclone to obtain fine overflow slurry and coarse underflow.

[0085] The required fineness of the material entering the ball mill is -3mm, accounting for 86wt%. After primary slurry preparation, the grinding concentration entering the ball mill is 66wt%. After secondary slurry preparation, the feed concentration entering the hydrocyclone is 33wt%. The fineness requirement for the fine overflow slurry is -200 mesh, accounting for 46wt%, and the fineness requirement for the coarse underflow is -200 mesh, accounting for 3wt%.

[0086] Collector is 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 subjected to a fourth classification to obtain coarse sand and tailings. The coarse-grained flotation is carried out using a hydraulic flotation machine with a rising water flow rate of 7 L / min and an aeration rate of 0.95 m³ / min. The collector and its usage are as follows: mixed oil dosage of 180 g / t and No. 2 oil dosage of 25 g / t; the mixed oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1.

[0087] In this embodiment, the early tailings disposal yield is 24.48%. The gravel 1, gravel 2, gravel 2, stone powder obtained from the dry tailings disposal process and the coarse sand obtained from the wet tailings disposal 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.

[0088] The yield, molybdenum grade, and molybdenum recovery rate of the raw molybdenum ore and the final tailings are summarized in Table 2, and the results are shown in the table below.

[0089] Table 2

[0090] weight / t Yield / % Molybdenum grade / % Molybdenum recovery rate / % raw 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 3 stones 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

[0091] Example 3

[0092] A method for pre-beneficiation tailings removal in low-grade molybdenum ore, comprising the following steps:

[0093] (1) Coarse crushing and sorting process: The low-grade molybdenum ore with a molybdenum grade of 0.0907% is coarsely crushed and then medium crushed, and then subjected to the first classification process through a double-layer screen to obtain the oversize ore, intermediate ore and undersize ore;

[0094] (2) Fine crushing process: The ore on the screen is finely crushed and then returned to the first classification;

[0095] The first grading process uses a double-layer sieve with an upper sieve aperture diameter of 30mm and a lower sieve aperture diameter of 5mm.

[0096] (3) Dry tailings disposal process: The intermediate ore is transported to the intelligent separator for separation to obtain coarse concentrate and coarse tailings. The coarse tailings are then classified a second time through a multi-layer screen to obtain dry tailings with different particle sizes.

[0097] The second classification uses a multi-layer sieve with a top sieve aperture diameter of 20mm, a middle sieve aperture diameter of 10mm, and a bottom sieve aperture diameter of 3mm. The resulting dry 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 of ≤3mm.

[0098] (4) Wet tailings disposal process: After the coarse concentrate is fed to the high-pressure roller mill for further crushing, it is classified for the fifth time through a sieve with a screen diameter of 3mm. The coarse concentrate on the screen is fed back to the high-pressure roller mill. The coarse concentrate and the undersize ore are slurried once and fed to the ball mill for grinding. After the grinding product is slurried a second time, it is classified for the third time through a hydrocyclone to obtain fine overflow slurry and coarse underflow.

[0099] The required fineness of the material entering the ball mill is -3mm, accounting for 82wt%. After primary slurry preparation, the grinding concentration entering the ball mill is 68wt%. After secondary slurry preparation, the feed concentration entering the hydrocyclone is 35wt%. The fineness requirement for the fine overflow slurry is -200 mesh, accounting for 52wt%, and the fineness requirement for the coarse underflow is -200 mesh, accounting for 2.7wt%.

[0100] Collector is 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 subjected to a fourth classification to obtain coarse sand and tailings. The coarse-grained flotation is carried out using a hydraulic flotation machine with a rising water flow rate of 8 L / min and an aeration rate of 1 m³ / min. The collector and its usage are as follows: 200 g / t of mixed oil and 30 g / t of No. 2 oil; the mixed oil is obtained by mixing diesel and kerosene in a weight ratio of 4:1.

[0101] The gravel 1, gravel 2, gravel 2, stone powder obtained from the dry tailings disposal process, as well as the coarse sand obtained from the wet tailings disposal 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.

[0102] The yield, molybdenum grade, and molybdenum recovery rate of the raw molybdenum ore and the final tailings are summarized in Table 3, and the results are shown in the table below.

[0103] Table 3

[0104] weight / t Yield / % Molybdenum grade / % Molybdenum recovery rate / % raw 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 3 stones 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

[0105] Comparative Example 1

[0106] A method for pre-beneficiation tailings removal in low-grade molybdenum ore, comprising the following steps:

[0107] (1) Coarse crushing and sorting process: 88t of low-grade molybdenum ore with a molybdenum grade of 0.0826% is coarsely crushed and then medium crushed, and then subjected to the first classification process through a sieve with a screen diameter of 30mm to obtain the oversize ore and undersize ore.

[0108] (2) Fine crushing process: The ore on the screen is finely crushed and then returned to the first classification;

[0109] (3) The undersize ore is first pulped and then fed into a ball mill for grinding. The grinding product is then pulped a second time and then classified a third time by a hydrocyclone to obtain fine overflow slurry and coarse underflow.

[0110] The material entering the ball mill is required to have a fineness of -3mm (82wt%). After primary slurry preparation, the grinding concentration entering the ball mill is 68wt%. After secondary slurry preparation, the feed concentration entering the hydrocyclone is 35wt%. The fineness requirement for the fine overflow slurry is -200 mesh (52wt%), and the fineness requirement for the coarse underflow slurry is -200 mesh (2.7wt%). The coarse underflow ore is returned to the ball mill, and the fine overflow slurry is used as flotation feed for molybdenum flotation to obtain molybdenum concentrate.

[0111] The final molybdenum grade of the flotation feed was 0.0826%, and the molybdenum recovery rate was 62%.

[0112] The technical solutions of Examples 1 to 3 and Comparative Example 1 were used to perform pre-flotation tailings removal on low-grade molybdenum ore. In Examples 1 and 3, the molybdenum grade of the flotation feed was significantly improved, and the molybdenum recovery rate reached over 95%. This shows that by using the technical solutions provided in this application, and combining dry and wet tailings removal processes, the raw molybdenum ore is pre-treated with tailings removal before the molybdenum flotation process, thereby improving the grade of the molybdenum flotation feed and thus increasing the molybdenum recovery rate after the molybdenum flotation process.

[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for pre-processing tailings removal in low-grade molybdenum ore beneficiation, characterized in that, include: (1) Coarse crushing and sorting process: After coarse crushing and medium crushing, the raw molybdenum ore is first classified by a double-layer screen to obtain oversize ore, intermediate ore and undersize ore; the upper screen of the double-layer screen has a diameter of 30 mm and the lower screen has a diameter of 5 mm. (2) Fine crushing process: The ore over the screen is finely crushed and then returned to the first grading process; (3) Dry tailings disposal process: The intermediate ore is fed to an intelligent separator for separation to obtain coarse concentrate and coarse tailings. The coarse tailings are then classified a second time through a multi-layer screen to obtain dry tailings with different particle sizes. The second classification uses a multi-layer screen with a top layer screen hole diameter of 20 mm, a middle layer screen hole diameter of 10 mm, and a bottom layer screen hole diameter of 3 mm. (4) Wet tailings disposal process: The coarse concentrate and the screened ore are slurried once and then fed into a ball mill for grinding. After the grinding product is slurried a second time, it is classified a third time by a hydrocyclone to obtain fine overflow slurry and coarse underflow. A collector is added to the coarse underflow and coarse flotation is performed to obtain coarse concentrate and coarse tailings. The coarse concentrate is returned to the ball mill, and the coarse tailings are classified into coarse sand and tailings through a fourth classification. The fine-grained overflow slurry was used as flotation feed for molybdenum flotation to obtain molybdenum concentrate; The method further includes: feeding the coarse concentrate to a high-pressure roller mill for further crushing, then performing a fifth classification through a sieve with a screen diameter of 3 mm to obtain the coarse concentrate on the screen, which is then fed back to the high-pressure roller mill; the coarse concentrate on the screen and the ore on the screen are then mixed once to form a slurry, which is then fed to a ball mill for grinding.

2. The method for pre-processing tailings removal of low-grade molybdenum ore according to claim 1, characterized in that, The particle size of the ore discharged after coarse crushing is ≤300mm, the particle size of the ore discharged after medium crushing is ≤150mm, and the particle size of the ore discharged after fine crushing is ≤60mm.

3. The method for pre-processing tailings removal of low-grade molybdenum ore according to claim 1, characterized in that, The dry 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 of ≤3mm.

4. The method for pre-processing tailings removal of low-grade molybdenum ore according to claim 1, characterized in that, The fineness requirement of the material entering the ball mill is -3mm ≥ 70wt%, and the grinding concentration of the material entering the ball mill after the first pulping is 65-68wt%.

5. The method for pre-processing tailings removal of low-grade molybdenum ore according to claim 1, characterized in that, The feed concentration entering the hydrocyclone after secondary slurry preparation is 30-35 wt%, the fineness requirement of the fine overflow slurry is -200 mesh content ≥ 40 wt%, and the fineness requirement of the coarse underflow is -200 mesh content ≤ 5 wt%.

6. The method for pre-processing tailings removal of low-grade molybdenum ore according to claim 1, characterized in that, The coarse particle flotation uses a hydraulic flotation machine with a rising water flow rate of 5-8 L / min and an aeration rate of 0.8-1 m³ / min.

7. The method for pre-processing tailings removal of low-grade molybdenum ore according to any one of claims 1-6, characterized in that, The collector and its dosage 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.

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