MQY2736 Overflow Ball Mill - High-Efficiency Energy-Saving Grinding for Mineral Processing Plants

In 'MQY', 'M' stands for Mill, 'Q' stands for Ball (Qiu in pinyin), and 'Y' stands for Overflow (Yichu in pinyin). The '2736' represents the effective shell diameter of 2700 mm and effective shell length of 3600 mm. Therefore, the MQY2736 is an overflow-type ball mill with a shell size of Φ2700×3600 mm. The corresponding MQG series uses 'G' for Grate discharge, with the two types differing in discharge principle and applicable applications.

An overflow ball mill discharges pulp when the pulp level inside the shell rises above the discharge trunnion opening — qualified fines naturally overflow out while coarse particles remain for further grinding. This produces a very uniform product with minimal over-grinding, making it ideal for primary or secondary grinding where fine product size is required. A grate ball mill has a grate plate at the discharge end that forces pulp out, keeping the pulp level and material bed lower inside the shell. This allows grinding media to deliver more impactful strikes, achieving higher throughput per unit volume, but with relatively more over-grinding — making it better suited for coarse grinding or high-tonnage applications.

The grinding media (steel ball) charge directly affects grinding efficiency and energy consumption. The MQY2736 has a maximum ball charge of 37 tonnes, with operating filling ratio typically controlled between 35% and 45%. Too few balls reduces impact grinding and lowers throughput; too many reduces effective shell volume, actually decreasing grinding efficiency while increasing motor load. We recommend starting with a 40% filling ratio (approximately 30 tonnes) and adjusting based on actual grinding performance. Ball size gradation should use a rational mix of large, medium, and small diameters — following the principle of 'large balls for impact breakage, medium balls for grinding, small balls for fine finishing'.

Three main liner material options are available: High-manganese steel (ZGMn13) liners offer excellent work-hardening characteristics where surface hardness continuously increases under impact wear — suitable for coarse feed and primary grinding with a service life of approximately 6-12 months. Alloy steel liners, with added chromium and molybdenum for enhanced initial hardness and wear resistance, are suited for medium and fine grinding with a service life of approximately 8-14 months. Rubber liners feature low noise, light weight, and corrosion resistance, ideal for fine and secondary grinding with a service life of up to 12-18 months. We can recommend the optimal liner solution based on your specific material characteristics and grinding duty.

Hydrostatic-hydrodynamic bearing lubrication is a composite lubrication method. Before ball mill startup, a high-pressure oil pump injects lubricant into the bearing base at 10-20 MPa, forming a high-pressure oil film approximately 0.1-0.2 mm thick between the journal and bearing pad. This lifts the rotating assembly weighing tens of tonnes completely off the pad surface, achieving pure liquid-friction startup with zero metal-to-metal contact. Once operating speed is reached, the high-pressure pump automatically stops and the system switches to hydrodynamic lubrication where journal rotation self-generates the load-bearing oil film. This eliminates dry-friction startup damage to the bearing alloy, dramatically extends bearing life, and reduces starting current and torque to protect the motor and drive system.

Key daily maintenance includes: First, regularly inspect pinion-girth gear meshing clearance and tooth surface wear, and promptly replenish or replace gear lubricant. Second, monitor bearing temperature and return oil temperature — normal bearing temperature should be below 55°C and return oil below 50°C; any abnormal temperature rise requires immediate shutdown for investigation. Third, regularly check liner bolt torque to prevent liner loosening and detachment. Fourth, periodically replenish grinding media to maintain proper ball charge and size gradation. Fifth, inspect feed and discharge trunnion seals to prevent pulp leakage. We recommend establishing a tiered maintenance schedule of daily inspection, weekly minor check, and monthly major check.

Yes, absolutely. We provide a comprehensive 12-month warranty for the MQY2736 overflow ball mill covering the main machine structure, steel shell, and drive system (excluding consumable wear parts such as liners, steel balls, and seals), protecting against structural failures caused by manufacturing defects or material quality issues, backed by full remote technical support and genuine OEM parts availability.