Huawei News

　　In the process of rapid industry development, the adoption of reasonable and advanced technologies can effectively improve industrial efficiency. This is particularly true for the mineral processing industry. The application of high-pressure roller mills in the material crushing stage, along with continuous optimization, can significantly improve the automation level and operational stability of the equipment, reduce unit crushing energy consumption, and enhance mineral processing capacity. This leads to better application results for high-pressure roller mills in mineral processing. Therefore, it is essential to first clarify the working principle and structural characteristics of high-pressure roller mills, and then discuss their application in different mineral processing processes and at different stages, for reference.

　　With the rapid development of the mineral processing industry, mining equipment has received increasing attention. Among these processes, grinding plays a crucial role, leading to the increasingly widespread application of high-pressure roller mills. However, due to certain limitations in their use, the industry's development has been somewhat restricted. Meanwhile, my country's economic level continues to rise, resulting in a growing demand for mineral resources and a surge in mineral processing projects. Therefore, in-depth research and innovation of high-pressure roller mills are needed to improve their application effectiveness in mineral processing engineering.

01 Working principle

Working Principle

　　High-pressure roller mills are based on traditional mill technology and are manufactured using fully automated hydraulic pressure control. They can aggregate raw material particles under high pressure and subject them to extremely high-pressure compression, continuously reducing the gaps between materials. Simultaneously, the pressure continuously rises until it reaches a certain level, at which point the material being rolled will break. During high-pressure roller milling, the counter-rotating double rollers can increase the material's throughput speed while maintaining crushing pressure, thus improving crushing efficiency.

02 Structural features

Structural Characteristics

　　A high-pressure roller mill mainly consists of a frame, high-pressure rollers, and a transmission system, using a hydraulic system as its pressure source. During operation, the pressure of the high-pressure roller mill should be adjusted according to the properties of the material. When adjusting the pressure, the hydraulic cylinder moves along the guide groove, and the material being processed moves continuously under the drive of the reducer, gradually being processed into compacted blocks. Compared to traditional mills, the extrusion rate of a high-pressure roller mill is more stable, but the actual speed is relatively lower. Therefore, if the operating speed is adjusted to a high level, material slippage is likely, which may affect the performance and lifespan of the high-pressure roller mill.

Application of high-pressure roller mills in the processing of different types of minerals

■ Dissociation and crushing of diamond ore

　　When high-pressure roller mills are applied to the dissociation and crushing of diamonds, the problem of low capacity in the crushing system can be solved, and the overall system operating capacity can be increased by up to 600 t/a. Furthermore, the quality of the diamonds is not adversely affected after being crushed by the high-pressure roller mill. Simultaneously, because the equipment is mainly driven by a fixed-speed motor, the amount of minerals processed can be continuously increased. After optimization of the high-pressure roller mill, its mineral processing effect can be further improved. This is because the optimized high-pressure roller mill has increased drive power of the geared motor, a smoother roller surface, and higher hardness. It also allows for regular roller surface replacement according to mineral processing needs, further improving operational efficiency.

▎High-pressure roller mill working site

■ Iron ore processing

　　The primary purpose of using high-pressure roller mills in iron ore processing is to pre-treat or crush ore materials. This improves the pelletizing properties of the material, reduces the incidence of various defects during processing, effectively controls losses, significantly lowers labor costs, increases the crushing system's capacity, and reduces energy consumption. With advancements in technology, high-pressure roller mills have been further improved, with substantial increases in roller width, roller diameter, and processing capacity, thus enhancing the precision of iron ore processing.

1.Common iron ore processing techniques：

2. A certain ilmenite ore modification process：

　　A certain ilmenite mine in Xinjiang originally used four ball mills for fine crushing, with three in operation and one on standby. The product had a 10mm feed size and an output particle size of -3mm. Based on its characteristics, we modified the process, replacing the four ball mills with one HPGM1480 high-pressure roller mill, significantly reducing energy consumption in fine crushing. The modified process is as follows:

　　This renovation requires the addition of one HPGM1480 high-pressure roller mill, two belt conveyors, a new roller press buffer hopper, and other infrastructure investments such as the roller press installation foundation.

　　The HPGM1480 roller press has an installed power of 1260KW and a throughput of approximately 420-630 tons. Based on material conditions, the expected throughput is around 550 tons. With three lines processing approximately 170 x 3 = 510 tons per hour, and the material first undergoes screening (assuming over 80% material purity), the hourly throughput is approximately 410 tons. The roller press is expected to achieve a 70% yield per pass, resulting in 410 x 1.3 = 533 tons, which is close to the expected throughput of 550 tons. After modification, the actual operating throughput of the roller press is 450 t/h, basically consistent with the design.

Benefit Analysis：

　　Based on the installed power of three mills (1400 x 3 = 4200 kW), each mill can process 410 tons per hour, consuming 10.2 kWh per ton. In contrast, the roller press (1260 kW) processes 410 tons per hour, consuming approximately 3.2 kWh per ton, resulting in a saving of 7 kWh per ton. Assuming a daily processing capacity of 8000 tons of ore, this translates to a daily saving of 56,000 yuan. At a price of 0.5 yuan per kWh, this equates to a monthly saving of 840,000 yuan in electricity costs.

Modified production line：

■ Processing of non-ferrous and other metal mines

　　The replacement of conventional fine crushing equipment with high-pressure roller mills can reduce the particle size of crushed ore products to 7mm. The application of high-pressure roller mills improves the grindability of ore, enhances the processing efficiency of ball mills, and can increase processing capacity by up to 15%. Compared to a three-stage closed-circuit crushing method, high-pressure roller mills require less investment in crushing processes, resulting in significant cost reductions.

　　In fine crushing operations, a high-pressure roller mill is used for crushing. When the ore feed size is 25mm, the crushed particle diameter can reach 7mm. The crushed product can be directly transferred to the powder silo without passing through a closed-circuit screen.

Applications of high-pressure roller mills in different stages of mineral processing

■ Fine/ultrafine crushing processing

Mineral Crushing Experimental Sieve Table1

Mineral crushing experiment sieve table 2

　　By using a high-pressure roller mill, most mineral materials with a particle size of 20-65mm can be crushed into fine materials with a particle size of less than 10mm, of which more than half are smaller than 3mm. These materials can then be used directly in subsequent ball milling circuits, or screened before being incorporated into the ball milling circuit. Furthermore, depending on specific process requirements, the high-pressure roller mill can participate in open-circuit operation or work in conjunction with a screening machine to implement closed-circuit operation. Because of the unique circuit configuration of the high-pressure roller mill, it is possible to separately extract and utilize the middle or peripheral products.

▎High-pressure roller mill working site

　　When a high-pressure roller mill is used in conjunction with a screening machine in a closed-loop operation, the screening particle size plays a decisive role in the feed particle size of the ball mill circuit and affects the proportion of crushing energy consumption between the subsequent high-pressure roller mill circuit and the ball mill circuit. Generally, as the particle size decreases, the crushing energy consumption of the high-pressure roller mill circuit increases, while the overall system energy consumption index decreases. Furthermore, the screening force decreases, increasing the difficulty of screening operations and reducing screening efficiency. Especially if the screening force is below 6mm, the efficiency of dry screening will significantly decrease, and in some cases, wet screening may be necessary. However, it is important to note that wet screening may result in excessive moisture content in the mineral material, which can affect the normal operation of the equipment and increase the overall system energy consumption.

■ Perform final grinding/semi-final grinding processing

　　In the mineral processing grinding process, there are mainly three stages: pre-grinding, semi-grinding, and final grinding. High-pressure roller mills can be used in all of these stages. However, in practice, in some stages, due to the large volume of the material, high-pressure roller mills cannot directly grind it to the required level. Therefore, ball mills are still needed to ensure that the final grinding effect meets the relevant requirements. See the table below for details:

 Application of high-pressure roller mills in final/semi-final grinding processes

▎High-pressure roller mill working site

▎High-pressure roller mill working site

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