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Rod Mil
The rod mill is a type of grinding mill used to grind materials into fine powder. It uses long steel rods as the grinding medium. It is used in mineral processing, cement, and other industries to break down or pulverize materials.
Capacity: 0.62-250 T/H
Application: Mainly used for coarse grinding operations. Suitable for fine crushing and coarse grinding of ores in the first stage of open-circuit grinding, especially suitable for processing brittle materials.
Rod Mill Types: There are three types of rod mills, including overflow rod mill, end-end peripheral discharge rod mill, and center peripheral discharge rod mill.
Rod Mill Overview
The rod mill is a tumbling mill used in mineral processing, cement, and other industries to grind raw materials into finer particles. Unlike ball mills, rod mills use long cylindrical steel rods as grinding media, resulting in coarser but more uniform particle size with fewer fines.
Applications
- Primary grinding in mineral processing (e.g., iron, tungsten, tin ores).
- Pre-grinding in cement production (raw materials or clinker).
- Coal/coke crushing (fuel preparation).
- Sand manufacturing (produces uniform grains).
Grinding Mechanism
- Line contact grinding: Rods grind via rolling and cascading, producing a more selective and controlled size reduction compared to ball mills.
- Reduced overgrinding: Lower fines generation due to cascading action rather than impact grinding.
Design & Operation
- Cylindrical shell: Rotates at 60–75% of critical speed (typically 10–18 RPM).
- Steel rods (grinding media): Usually slightly shorter than mill length to prevent tangling.
- L/D ratio: Typically 1.5:1 to 2.5:1 (longer for finer grinding).
- Filling ratio: Rods occupy 35–45% of mill volume.
- Feed size: ≤ 50 mm; product size range: 0.5–5 mm.
Advantages
Rod Mill Advantages
The rod mill, as an efficient grinding equipment, offers multiple advantages: Its unique low-speed operation and large-diameter cylinder design enable gentle crushing action, effectively handling coarse feed materials (with feed sizes up to 50mm) while significantly reducing over-grinding due to the linear contact grinding mechanism of steel rods, making it particularly suitable for producing medium-to-coarse particle sizes (1-3mm). Additionally, the rod mill features step-shaped liners and controlled discharge mechanisms, which not only enhance wear resistance and reduce maintenance costs (liner lifespan is over 30% longer than that of ball mills) but also enable precise particle size control (product size variation <5%). In applications such as coarse grinding of metal ores and cement clinker processing, its energy consumption is 15-20% lower than that of traditional equipment. Furthermore, its simple structure and stable operation ensure long-term availability exceeding 90%, making it especially well-suited for continuous industrial production.
✔ Wide Applicability: Rod mills are suitable for grinding various ores, including metallic ores (such as copper, lead, zinc, etc.), non-metallic ores (such as quartz, feldspar, etc.), and building materials (such as cement, glass, etc.).
✔ High Processing Capacity: Rod mills typically have a large processing capacity, capable of processing large quantities of ore.
✔ Excellent Grinding Effect: Due to the impact and friction of the steel rods, rod mills can produce a high grinding effect, achieving a finer particle size in the ore.
✔ Suitable for Coarse Grinding: Compared to ball mills, rod mills are more suitable for coarse grinding operations, effectively grinding larger ore particles into smaller ones.
Structures & Working Principle
Rod Mill Structure
A rod mill mainly consists of a cylinder, feeding and discharging devices, main bearing components, a transmission device, and large and small gears.
- Cylinder Section: The cylinder section of the rod mill mainly consists of the cylinder body, hollow shaft, and feeding and discharging bushings. Both sides are bolted to the hollow feeding and discharging shafts, which are horizontally supported on two main bearing bushes. The hollow feeding shafts contain a feed screw. The cylinder body is lined with wear-resistant plates, and rubber gaskets are installed between the cylinder cover and the steel liner plates for vibration damping and noise reduction. The bushings inside the hollow shaft provide protection. Each bolt on the liner plates has a sealing gasket to prevent leakage.
- Feeding and Discharging Devices: The feeding device typically uses a shoe-shaped hopper connected to the feeding equipment via a flange at the top. It receives the material and has an inspection door on the rear wall of the hopper, which is a cylindrical tube extending into the screw (mounted on the hollow shaft). The material enters the mill through this device. The discharging device is mainly a cover made of a steel plate.
- Main Bearing Section: The main bearing section of the rod mill consists of several parts: bearing cover, bearing housing, bearing liner, oil sprayer, oil level indicator, and flow cut-off plate.
- Gear Transmission Section: It adopts an open-edge type, with the large gear connected to the cylinder and the small gear connected to the input shaft of the reducer.
- Slow-Speed Drive Unit: The slow-speed drive unit of the rod mill mainly consists of three parts: clutch, reducer, and motor.
Rod Mill Working Principle
The working principle of a rod mill is to place the ore into a rotating cylinder containing a certain number and length of steel rods. Through the rotation of the cylinder and the impact and friction of the steel rods, the ore is ground into the required fine particles. The ore is continuously struck and crushed by the steel rods inside the rod mill, gradually becoming finer until the desired particle size is achieved.
Technical Parameters
| Model | Cylinder Diameter (mm) | Cylinder Length (mm) | Motor Power (kW) | Motor Speed (r/min) | Capacity (t/h) | Effective Volume (m3) | Weight (kg) |
| MBY0918 | 900 | 1800 | 22 | 730 | 0.62~3.2 | 0.9 | 5700 |
| MBY0924 | 900 | 2400 | 30 | 730 | 0.81~4.3 | 1.2 | 5880 |
| MBY1224 | 1200 | 2400 | 45 | 730 | 0.4~4.9 | 2.28 | 12308 |
| MBY1530 | 1500 | 3000 | 95 | 725 | 0.4~4.9 | 5 | 19990 |
| MBYg1530 | 1500 | 3000 | 80 | 725 | 2.4~7.5 | 5 | 21210 |
| MBYg2130 | 2100 | 3000 | 180 | 735 | 14~35 | 9 | 42123.5 |
| MBYg2136 | 2100 | 3600 | 210 | 735 | 43~61 | 10.8 | 45800.5 |
| MBYg2430 | 2400 | 3000 | 280 | 735 | 43~61 | 11.5 | 55795 |
| MBYg2732 | 2700 | 3200 | 320 | 750 | 43~61 | 15.7 | 83110 |
| MBYg2736 | 2700 | 3600 | 380 | 743 | 32~86 | 17.7 | 90441 |
| MBY2740 | 2700 | 4000 | 400 | 187.5 | 43~110 | 20.4 | 75000 |
| MBY3040 | 3000 | 4000 | 570 | 740 | 54~135 | 26 | 90000 |
| MBY3245 | 3200 | 4500 | 800 | 167 | 64~180 | 31 | 113000 |
| MBY3645 | 3600 | 4500 | 1250 | 150 | 80~230 | 41.8 | 139000 |
| MBY3654 | 3600 | 5400 | 1600 | 150 | 100~250 | 49.7 | 150000 |
