The multi-axis mill is a vertical-structure stirred mill. With its efficient, energy-saving, and ultra-fine friction-milling approach, it demonstrates significantly superior performance compared to conventional ball mills and rod mills in the fields of fine and ultra-fine grinding of coal-water slurry, making it an ideal equipment choice for efficient, low-energy consumption, and environmentally friendly coal utilization.

Multi-axis grinders have already been applied in industries such as coal chemical engineering, thermal power plants, and coal-water slurry gasification. They are particularly well-suited for the fine grinding of slurries made from various types of coal, including lignite, bituminous coal, and lean coal. These grinders can effectively enhance the fineness, stability, and rheological properties of coal-water slurries, ensuring that the slurry meets the stringent requirements of high concentration and low viscosity needed for boiler combustion and gasification processes.

  Multi-axis grinding unit composition and working principle:

The equipment consists of a compact multi-axis grinding unit, primarily comprising a drive motor, gearbox, multi-axis helical agitator, grinding chamber, frame, and lubrication system. The multi-axis design enables higher grinding frequencies and more uniform energy distribution within a given volume, ensuring rapid and even mixing of coal powder with water, as well as fine particle refinement—thus maintaining stable particle size distribution in the coal-water slurry.

Working principle: Coal and water enter the equipment from the top and move downward step by step under gravity. Inside, multi-axis spiral blades rotate at high speed, generating a powerful centrifugal force field that thoroughly disperses the coal material. This process creates intense high-frequency friction and shear between the coal particles and the grinding media, continuously refining the particles, increasing their surface area, and ensuring complete wetting with water. The result is a stable slurry with high concentration and low viscosity, ready for direct use in combustion or gasification.

Seven Major Advantages of Multi-Axis Grinding

1. Fineness is controllable, and particle gradation is well-optimized: ensuring stable production. Coal powder particles with d90 < 20 μm exhibit a continuous particle distribution in the slurry, enhancing the rheological properties of coal-water slurry, reducing viscosity, and improving both transportability and combustion efficiency.

2. High concentration, low viscosity: Through multi-axis shearing and uniform dispersion, the coal powder surface is thoroughly wetted, enhancing slurry stability and ensuring that the slurry concentration can reach 65% to 70%, still maintaining low viscosity, meeting the requirements of industrial boilers and gasification furnaces.

3. Significant energy savings: Compared to traditional ball mills, energy consumption per unit is reduced. 30% to 50%, with lower energy consumption at the same coal slurry preparation capacity, reducing the operating costs of the slurry system.

4. Highly adaptable: It can directly handle coal types with varying moisture levels and hardnesses without requiring pre-drying, thus preventing the inefficiencies often encountered when using vertical mills or ball mills to process high-moisture coal.

5. High grinding efficiency: Multi-axis mixing creates more complex movement patterns for the grinding media, enhancing both shear and friction effects. This allows coal powder particles to be rapidly refined within a confined space, resulting in highly uniform slurry quality.

6. The system is stable and easy to scale: featuring a vertical, compact design that occupies minimal space and enables continuous operation. Paired with a closed-loop classification system, it ensures controllable pulp particle size distribution, high slurry uniformity, and classification efficiency exceeding 95%.

7. Eco-friendly Noise Reduction: The equipment operates with low noise levels and minimal dust leakage; the pulp preparation process is fully enclosed, significantly reducing coal dust pollution while aligning with green, low-carbon process requirements.

Application Value:

In the preparation of coal-water slurry, multi-axis grinders not only ensure the slurry's fineness and stability but also reduce unit energy consumption and slurry-making costs, making coal-water slurry—already a crucial component of clean coal technology—more economically viable. Their highly efficient fine-grinding capability delivers high-concentration, low-viscosity, and stable coal-water slurry suitable for processes such as boiler combustion and coal gasification, thereby enhancing combustion efficiency and energy utilization rates.

Efficient coal slurry preparation is a critical step in achieving clean and efficient coal utilization. Traditional ball mills suffer from high energy consumption, low efficiency, and difficulty meeting the demands for preparing high-concentration slurries. Fortunately, the emergence of multi-axis grinders has effectively addressed this technological bottleneck, providing robust equipment support for China’s efforts in clean coal utilization and the upgrading of its coal-to-chemicals industry.