Efficient and energy-saving ore crushing and grinding process

Abstract

According to the efficient and energy-saving ore crushing and grinding process, efficient crushing and energy-saving ore grinding are achieved through multi-stage cooperative crushing and ore grinding of the gyratory crusher, the cone crusher, the high-pressure roller mill, the semi-autogenous mill and the overflow type ball mill in combination with the grading effect of the hydrocyclone. According to the process, an optimized closed-loop circulation system and a flexible shunting design are adopted, the process flow can be automatically adjusted according to the operation state of equipment, the energy consumption is remarkably reduced, and the treatment efficiency is improved. The specially designed emergency process can maintain continuous production when the semi-autogenous mill is shut down.

Description

Technical Field

[0001] The present invention relates to the technical field of ore crushing and grinding, and more specifically to a highly efficient and energy-saving ore crushing and grinding process suitable for ore processing in large-scale mineral processing plants. The invention aims to solve the problems of high energy consumption, high steel consumption, and large fluctuations in processing volume in existing crushing and grinding processes. Background Art

[0002] In the field of mineral processing, ore crushing and grinding operations are the key link, and its energy consumption accounts for more than 70% of the total energy consumption of mineral processing. The quality of the crushing and grinding process directly determines the production process indicators and economic benefits of the beneficiation plant.

[0003] Early comminution and grinding processes primarily employed traditional multi-stage crushing and ball milling. While this technology was mature, it presented challenges such as complex processes, high investment costs, large floor space requirements, and significant energy and steel consumption. With the development of the industry, semi-autogenous grinding (SAG) has gradually gained popularity and is widely used in large-scale mines both domestically and internationally. SAG offers significant advantages such as a simple process flow, low investment costs, a small footprint, and minimal operator requirements. This effectively simplifies the production process and reduces initial investment and operating costs.

[0004] However, the SAG process has exposed a series of problems that need to be solved during its application. On the one hand, the problems of high steel and energy consumption are significant. The large amount of steel ball consumption increases production costs. At the same time, high energy consumption is not in line with the development trend of green energy conservation. On the other hand, its processing capacity fluctuates greatly due to the properties of the ore and the particle size of the feed. When the hardness, structure and other properties of the ore change or the particle size of the feed is uneven, the efficiency and processing capacity of the SAG mill will fluctuate greatly, affecting the stable production of the concentrator. In addition, the SAG system also has problems such as low yield of stubborn rock and poor stubborn rock crushing effect. The stubborn rock cannot be effectively crushed, which not only reduces the production capacity of the grinding system, but also may cause increased wear of the equipment.

[0005] To address these issues, the industry has attempted to introduce technologies such as high-pressure roller grinding (HPGR). However, traditional single processes struggle to achieve a high degree of compatibility with ore properties and feed particle size, and thus fail to fully leverage the synergistic advantages of different equipment. Therefore, developing an efficient and energy-efficient crushing and grinding process that addresses high steel and energy consumption while enhancing rock crushing to maximize grinding system capacity and reduce unit energy consumption has become a pressing technical challenge in this field. Summary of the Invention

[0006] In order to solve the problems of high steel consumption, high energy consumption and large fluctuation of processing volume in the semi-autogenous grinding process of large-scale mineral processing plants, the present invention provides an ore crushing and grinding process that is efficient, stable, energy-saving and has a high equipment operating rate. By optimizing the process design and equipment combination, the crushing and grinding process is highly adapted to the ore properties and feed particle size, thereby improving production capacity and reducing energy consumption.

[0007] In order to achieve the above object, the specific scheme adopted by the present invention is: A highly efficient and energy-saving ore crushing and grinding process, including two operating modes: SAG mill active state and SAG mill inactive state: When the SAG mill is shut down, the following steps are involved: (I) The raw ore is coarsely crushed by a gyratory crusher, and the coarsely crushed products are transported to the main ore bin via a belt conveyor; (II) The ore in the main ore bin is conveyed by a vibrating feeder via a belt to a vibrating screen for pre-screening to obtain oversize ore and undersize ore; (III) The ore on the screen is fed into a cone crusher to obtain a cone crusher product, which is then transported to the main ore bin via a belt conveyor, and step (II) is repeated; (IV) The ore under the screen enters the high pressure roller mill to obtain a high pressure roller mill product; the high pressure roller mill product is sorted and divided into a side product and a core product; the side product returns to the high pressure roller mill for further crushing; the core product directly enters the overflow ball mill to obtain a grinding slurry; the grinding slurry flows into the pump tank by gravity through a pipeline; (V) The slurry in the pump pool is transported to the cyclone by a slurry pump for classification to obtain a grit slurry and an overflow slurry; the overflow slurry flows into the flotation system through a pipeline for flotation operation, and the grit slurry returns to the overflow ball mill for further grinding; When a semi-autogenous mill is put into operation, the following processes are involved: (1) The raw ore is coarsely crushed by the gyratory crusher, and the crushed products are transported to the main ore bin via a belt conveyor; (2) The ore in the main ore bin is conveyed to the vibrating screen via a vibrating feeder via a belt for pre-screening to obtain the oversize ore and undersize ore; the undersize ore enters the high pressure roller mill to obtain the high pressure roller mill product; (3) The ore in the main ore bin is conveyed by a vibrating feeder via a belt to a vibrating screen for pre-screening to obtain oversize ore and undersize ore; the oversize ore is combined with the first circulating material and enters the cone crusher to obtain the medium crushed product; the undersize ore enters the high pressure roller mill to obtain the high pressure roller mill product; (4) The medium crushed product is fed into the vibrating feeder to form the second circulating material, which is mixed with the raw materials on the semi-autogenous grinding feeding belt and fed into the semi-autogenous grinding mill to form a closed-circuit circulation system; (5) The products of the HPGR are sorted into side products and core products; the side products are returned to the HPGR for further crushing; the core products can be selected from: (a) enters the SAG mill via a SAG feed belt and participates in the closed-circuit system of steps (2) to (4); or (b) directly entering an overflow ball mill to obtain a grinding slurry; the grinding slurry flows into a pump tank by gravity through a pipeline; (6) The slurry in the pump pool is transported to the cyclone through the slurry pump for classification, and the sand slurry and overflow slurry are obtained; the overflow slurry flows into the flotation system through the pipeline for flotation operation, and the sand slurry returns to the overflow ball mill for further grinding.

[0008] Furthermore, the cyclone is a hydrocyclone.

[0009] Beneficial effects: (1) The present invention creatively designs a crushing and grinding process in which the "high-pressure roller mill-ball mill" and "high-pressure roller mill-sigmoidal mill-ball mill" (when the sigmoidal mill is in use) processes coexist, effectively utilizing the synergistic effect of the sigmoidal mill process and the two-stage crushing-high-pressure roller mill process. The simplicity and high efficiency of the sigmoidal mill process are combined with the enhanced crushing of the high-pressure roller mill to achieve a high degree of matching between the crushing and grinding process and the properties of the ore and the feed particle size. For example, for ores with higher hardness, the ore can be pre-"weakened" by the high-pressure roller mill, improving the feed particle size of the sigmoidal mill and the ball mill, enabling the sigmoidal mill to process materials more efficiently and reduce energy consumption.

[0010] (2) The coarse crushed ore pile can simultaneously supply ore to the semi-autogenous grinding system and the medium crushing-high pressure roller grinding system. The medium crushed product can also supply ore to the semi-autogenous grinding system. The center material product of the high pressure roller grinding can supply ore to both the semi-autogenous grinding system and the ball mill. The multiple feeding methods are interconnected, which increases the flexibility and optimization opportunities of the crushing and grinding system. When the semi-autogenous grinding mill needs to be shut down for maintenance, the ore feeding path can be adjusted so that the material can continue to be processed through the high pressure roller grinding-ball mill process, ensuring the continuous operation of the entire crushing and grinding system, effectively improving the equipment operation efficiency and reducing downtime losses.

[0011] (3) The semi-autogenous grinding mill has innovated the pre-crushing process and the two-stage crushing process of stubborn stones, which conforms to the technical concept of "more crushing and less grinding". After the medium crushing, the high-pressure roller mill is introduced for fine crushing. The high pressure of the high-pressure roller mill is used to generate a large number of cracks inside the ore, "weakening" the ore. In the subsequent grinding process, the ore is more easily crushed and ground, thereby enhancing the ore crushing effect. The semi-autogenous grinding mill has three different feed streams (raw ore, medium crushed product, high-pressure roller mill center product), which greatly optimizes the particle size distribution of the semi-autogenous grinding mill, makes the material particle size distribution in the semi-autogenous grinding mill more reasonable, reduces the wear of the equipment by coarse particles, and improves the crushing efficiency of the semi-autogenous grinding mill. Through these measures, the energy consumption of the crushing and grinding system is effectively reduced and the production capacity of the crushing and grinding system is increased. For example, under the same processing volume, the unit energy consumption can be significantly reduced, and the production capacity is increased.

[0012] (4) Combining the technical advantages of existing high-pressure roller mills and semi-autogenous mills, a crushing and grinding process that is economically reasonable, flexible, and highly adaptable to the properties of the ore has been developed. It integrates the processes of pre-crushing of semi-autogenous feed, two-stage crushing of stubborn stones, and high-pressure roller mill-ball milling. This process can flexibly adjust the process parameters and material flow of each link according to the properties of different ores (such as hardness, structure, mud content, etc.) and feed particle size to achieve the best crushing and grinding effect. It effectively reduces the unit power consumption of the semi-autogenous mill and increases the processing capacity of the semi-autogenous mill. It is an efficient, stable and energy-saving crushing and grinding process. It has important guiding significance for the optimization of crushing and grinding processes, capacity improvement, cost reduction and efficiency improvement of large-scale mineral processing plants, and can significantly improve the economic benefits and market competitiveness of mineral processing plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic diagram of the ore crushing and grinding process flow in the present invention.

[0014] Figure numerals: 1. gyratory crusher, 2. main hopper and vibrating feeder, 3. vibrating screen, 4. cone crusher, 5. high pressure roller mill, 6. semi-autogenous mill, 7. pump tank, 8. overflow ball mill, 9. cyclone. DETAILED DESCRIPTION

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0016] Example 1 An efficient and energy-saving ore crushing and grinding process (using a semi-autogenous grinding mill) includes the following steps: (1) Coarse crushing: The raw ore is fed into the gyratory crusher 1 for coarse crushing. The discharge port size of the gyratory crusher 1 is CSS = 165 mm. The content of -110 mm particle size in the coarse crushed product accounts for 80% of the total mass of the coarse crushed product. The coarse crushed product is conveyed to the main ore bin 2 via a belt conveyor. In this step, the raw ore is initially crushed to a suitable particle size by the gyratory crusher 1, providing raw materials for subsequent grinding. The belt conveyor ensures the stability and continuity of material transportation. (2) Semi-autogenous grinding and screening: The main ore bin 2 is adjacent to the vibrating feeder. The ore from the main ore bin is fed by the vibrating feeder and the semi-autogenous grinding feeding belt into the semi-autogenous grinding mill 6 for grinding. The grinding product is screened by a cylindrical screen (15mm×35mm). The material on the cylindrical screen is stubborn stone. The -27mm particle size content of the stubborn stone on the screen accounts for 80% of the total mass of the stubborn stone. The stubborn stone is transported to the vibrating feeder through a belt to form the first circulating material. The under-screen slurry enters the pump pool 7. The -1.9mm particle size content in the slurry accounts for 80% of the total mass of the ore it contains. In this step, the semi-autogenous grinding mill 6 grinds the coarse ore. The cylindrical screen separates the grinding product into stubborn stone and slurry. The stubborn stone returns to the vibrating feeder to form the first circulating material, ensuring that the stubborn stone is processed again and improving the grinding efficiency. The under-screen slurry enters the pump pool 7 for subsequent classification processing. (3) Pre-screening: The ore from the main ore bin in step 1 is fed through a vibrating feeder and conveyed by a belt to a vibrating screen 3. The ore is screened by a vibrating screen 3 (45 mm × 45 mm) to obtain oversize ore and undersize ore. The -36 mm particle size content of the undersize ore accounts for 80% of the total feed. The pre-screening of the vibrating screen 3 separates the coarse ore into oversize and undersize ore, providing conditions for subsequent different crushing treatment paths, so that the material can be crushed into medium and fine crushing according to the particle size, thereby optimizing the process. (4) Secondary crushing: The oversize ore obtained in step 3 and the first circulating material obtained in step 2 are fed to a cone crusher 4 (CSS=45mm) via a belt to obtain a secondary crushed product; the -55mm particle size content in the secondary crushed product accounts for 80% of the total mass; the secondary crushed product is conveyed to a vibrating feeder via a belt to form a second circulating material; the formed second circulating material is conveyed to a semi-autogenous grinding feeding belt via a belt, mixed with the ore in the main ore bin on the semi-autogenous grinding feeding belt and fed to a semi-autogenous grinding mill 6 to form a closed-loop circulation system. In this step, the oversize ore and the first circulating material are combined and secondary crushed in a cone crusher to further reduce the particle size. The secondary crushed product is mixed with the coarsely crushed ore as the second circulating material and enters the semi-autogenous grinding mill to form a closed-loop circulation, ensuring that the material is fully ground and improving the particle size uniformity of the grinding product; (5) High-pressure roller milling: The undersize ore obtained in step 3 is fed into the high-pressure roller mill 5 to obtain a high-pressure roller mill product. The -16mm particle size content in the high-pressure roller mill crushed product accounts for 80% of the total mass of the product. The high-pressure roller mill product is divided into a side product and a core product; the side product returns to the high-pressure roller mill 5 for further crushing. In this step, the undersize ore enters the high-pressure roller mill 5 for fine crushing. The high pressure of the high-pressure roller mill 5 is used to generate cracks inside the ore, "weakening" the ore. The side product returns to be crushed again, thereby improving the crushing efficiency of the high-pressure roller mill 5 and the quality of the product particle size. (6) Processing options for the central product: The central product in step 5 is conveyed to the SAG feed belt via a belt, mixed with the materials on the SAG feed belt, and enters the SAG mill 6 to participate in the closed-loop circulation system; the central product enters the SAG mill 6, is mixed with other materials, and then is ground again to further optimize the particle size distribution of the SAG mill feed, thereby improving the crushing efficiency and processing capacity of the SAG mill. Alternatively, the central product directly enters the overflow ball mill 8 to obtain a grinding slurry; the grinding slurry flows by gravity into the pump tank 7 through a pipeline; (7) Cyclone classification: The slurry in the pump pool is transported to the cyclone 9 through the slurry pump for classification, and the grit slurry and overflow slurry are obtained; the overflow slurry is a qualified particle size product, and the -0.074mm particle size content in the overflow product accounts for 70% of its total mass. The overflow slurry concentration is 30%. It flows through the pipeline to the flotation system for flotation operation, and the grit slurry product flows through the pipeline to the overflow ball mill 8 for re-grinding. The cyclone classification divides the slurry into qualified overflow slurry and grit slurry that needs to be re-grinded. The overflow slurry directly enters the flotation system to improve production efficiency, and the grit slurry is re-grinded to ensure that the particle size of the grinding product meets the requirements. After being re-grinded in the ball mill, the grit slurry returns to the pump pool 7 for classification again to ensure that the material is fully ground and improve the quality of the grinding product.

[0017] Example 2 This embodiment discloses a highly efficient and energy-saving ore crushing and grinding process (without using a semi-autogenous grinding mill), including the following steps: (1) The raw ore is fed into the gyratory crusher for coarse crushing. The discharge port size of the gyratory crusher 1 is CSS = 165 mm. The content of -110 mm particle size in the coarse crushed product accounts for 80% of the total mass of the coarse crushed product. The coarse crushed product is conveyed to the main ore bin 2 via a belt conveyor. (2) The ore in the main ore bin is conveyed to the vibrating screen 3 by a vibrating feeder via a belt for pre-screening to obtain the ore above the screen and the ore below the screen; (3) The ore on the screen is fed into a cone crusher to obtain a cone crusher product, which is then transported to the main ore bin via a belt conveyor and step (II) is repeated. (4) The ore under the screen enters the high-pressure roller mill 5 to obtain the high-pressure roller mill product; the high-pressure roller mill product is sorted into a side product and a core product; the -25mm particle size content in the side product accounts for 80% of the total mass of the side product, and the side product returns to the high-pressure roller mill 5 for further crushing; the -8.2mm particle size content in the core product accounts for 80% of the total mass of the product, and the core product directly enters the overflow ball mill 8 to obtain a grinding slurry; the grinding slurry flows into the pump pool 7 through a pipeline by gravity; (5) The slurry in the pump pool is transported to the cyclone 9 through the slurry pump for classification, and the sand slurry and overflow slurry are obtained; the overflow slurry flows into the flotation system through the pipeline for flotation operation, and the sand slurry returns to the overflow ball mill 8 for further grinding.

[0018] When the semi-autogenous grinding mill is shut down, the processing path of the central product of the high-pressure roller mill is adjusted so that it directly enters the ball mill for grinding, thereby ensuring the continuous operation of the entire crushing and grinding system and reducing the impact of the shutdown on production, further demonstrating the advantages of the process of the present invention in terms of high efficiency, stability, flexibility and versatility.

[0019] The present invention discloses a highly efficient and energy-saving ore crushing and grinding process. Combining the technical advantages of existing high-pressure roller mills (HPGRs) and semi-autogenous mills (SAG mills), this process is economically sound, flexible, and highly adaptable to ore properties. This process integrates SAG feed pre-crushing, two-stage crushing of stubborn rock, and HPGR-ball milling, effectively reducing the SAG mill's unit power consumption and increasing its throughput. This highly efficient, stable, and energy-saving crushing and grinding process is of great significance for optimizing crushing and grinding processes, increasing production capacity, and reducing costs and increasing efficiency in large-scale mineral processing plants.

[0020] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any equivalent changes or modifications made based on the essence of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-efficiency and energy-saving ore crushing and grinding process, characterized in that: There are two working modes: SAG mill enabled state and disabled state: When the SAG mill is shut down, the following steps are involved: (I) The raw ore is coarsely crushed by a gyratory crusher, and the coarsely crushed products are transported to the main ore bin via a belt conveyor; (II) The ore in the main ore bin is conveyed by a vibrating feeder via a belt to a vibrating screen for pre-screening to obtain oversize ore and undersize ore; (III) The ore on the screen is fed into a cone crusher to obtain a cone crusher product, which is then transported to the main ore bin via a belt conveyor, and step (II) is repeated; (IV) The ore under the screen enters the high pressure roller mill to obtain a high pressure roller mill product; the high pressure roller mill product is sorted and divided into a side product and a core product; the side product returns to the high pressure roller mill for further crushing; the core product directly enters the overflow ball mill to obtain a grinding slurry; the grinding slurry flows into the pump tank by gravity through a pipeline; (V) The slurry in the pump pool is transported to the cyclone by a slurry pump for classification to obtain a grit slurry and an overflow slurry; the overflow slurry flows into the flotation system through a pipeline for flotation operation, and the grit slurry returns to the overflow ball mill for further grinding; When a semi-autogenous mill is put into operation, the following steps are involved: (1) The raw ore is coarsely crushed by the gyratory crusher, and the crushed products are transported to the main ore bin via a belt conveyor; (2) The ore in the main ore bin is conveyed to the vibrating screen via a vibrating feeder via a belt for pre-screening to obtain the oversize ore and undersize ore; the undersize ore enters the high pressure roller mill to obtain the high pressure roller mill product; (3) The ore in the main ore bin is conveyed by a vibrating feeder via a belt to a vibrating screen for pre-screening to obtain oversize ore and undersize ore; the oversize ore is combined with the first circulating material and enters the cone crusher to obtain the medium crushed product; the undersize ore enters the high pressure roller mill to obtain the high pressure roller mill product; (4) The medium crushed product is fed into the vibrating feeder to form the second circulating material, which is mixed with the raw materials on the semi-autogenous grinding feeding belt and fed into the semi-autogenous grinding mill to form a closed-circuit circulation system; (5) The products of the HPGR are sorted into side products and core products; the side products are returned to the HPGR for further crushing; the core products can be selected from: (a) enters the SAG mill via a SAG feed belt and participates in the closed-circuit system of steps (2) to (4); or (b) directly entering an overflow ball mill to obtain a grinding slurry; the grinding slurry flows into a pump tank by gravity through a pipeline; (6) The slurry in the pump pool is transported to the cyclone through the slurry pump for classification, and the sand slurry and overflow slurry are obtained; the overflow slurry flows into the flotation system through the pipeline for flotation operation, and the sand slurry returns to the overflow ball mill for further grinding.

2. The high-efficiency and energy-saving ore crushing and grinding process according to claim 1, characterized in that: The cyclone is a hydrocyclone.

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