One of the most important components in the ceramic tile production line is the ball mill. It plays a crucial role in the production process of ceramic tiles. After the crushing stage, where raw materials are ground and prepared, the ball mill process begins as the second stage in the production line.

To produce the biscuit (raw ceramic tile body), the required powder must first be prepared. This powder is produced through the drying process of the slurry in a spray dryer in the ceramic factory. Additionally, the slurry itself is produced via the ball mill process. In fact, the ball mill, or ball grinding mill, is a key piece of equipment in the ceramic industry that plays a fundamental role in the slurry production process. This device is a rotating cylinder filled with balls. The following sections will review the operation and details of this device.

Ball Mill Function and Its Role in Ceramic Production

In the ceramic tile production process, before preparing the biscuit (raw body of the tile), a uniform powder must be produced. This powder is obtained through the slurry-making process in the ball mill. The raw materials, including kaolin, feldspar, silica, and other mineral compounds, along with water, enter the ball mill and are converted into slurry under the influence of the rotating balls. The density, viscosity, and residue of the slurry are important at this stage and must be adjusted according to the production process. Inside the mill, there are balls that, as the mill rotates, crush and grind the raw materials by colliding with the balls and the mill's wall. It is evident that when the mill rotates, the balls, in addition to colliding with the raw materials, also collide with each other and the mill wall. As a result, some of these materials will be worn down and added to the original mixture (the material separated from the walls and grinding debris from the balls will be included in the raw materials). For this reason, the composition of the mill’s interior wall and the balls is crucial in the ceramic and tile production process.

Components of the Ball Mill and Their Role

• Ball Mill Body:
  The body is typically made of steel and is lined with various materials inside to protect it.

• Internal Liners:
  Made from various materials such as steel, alubit, rubber, or basalt, these liners help protect the body and improve grinding efficiency. Most mill walls are made from rubber, but today, alubit liners are also used.

• Grinding Balls:
  These balls are made from different materials, including alubit, steel, and basalt, and play a role in enhancing the grinding process. Sometimes, river stones (silica, feldspar-silica, and sometimes limestone) are used to grind the body material. It's preferable to use silica balls because limestone and feldspar cause more wear.

Ball Mill Rotation Speed and Ball Acceleration in Ceramic Slurry Preparation

The rotation speed of the ball mill is a critical factor in the grinding and crushing process. If the speed is too high, the balls will stick to the walls of the cylinder, halting the grinding process. Conversely, if the speed is too low, the balls will not have an effective movement, and grinding will not occur adequately. The best performance occurs when a balance is achieved between the sliding and cascading motion of the balls.

• Low Acceleration:
  If the acceleration of the balls is low, they will not fall effectively, and the grinding process will not occur, resulting in high wear on the balls and walls.

• Medium Acceleration:
  If the acceleration of the balls is optimal, the best grinding conditions are created. Both cascading and rotational movements occur, complementing each other.

• Excessive Acceleration:
  If the acceleration is too high, centrifugal force will cause the balls to stick to the walls, significantly reducing the efficiency of the process.

Types of Ball Mills

Ball mills can be classified based on various criteria, such as the axis direction and the method of material entry and exit. Here, we will focus on three main classifications:

1. Ball Mills Based on Axis Direction:

   • Horizontal Ball Mill:
     The most common type of ball mill in industrial applications. These mills are cylindrical and installed horizontally. The materials and grinding media move inside them in a rotational motion. Horizontal mills are widely used in mineral processing, cement production, and chemical industries. They are effective for grinding materials from coarse to fine sizes and have a simple design, making them easy to maintain.

   • Vertical Ball Mill:
     Unlike horizontal mills, these mills are vertically oriented. This design increases energy efficiency and reduces space occupancy. Vertical mills are typically used for fine grinding applications, such as ink, coatings, and pharmaceuticals. Their ability to process finer particles makes them ideal for high-quality materials.

2. Ball Mills Based on Material Feeding and Discharging:

   • Continuous Ball Mill:
     In continuous ball mills, materials are fed into the mill from one side, and the slurry is continuously discharged from the other side after the grinding process. This type is ideal for large-scale production and is suitable for continuous manufacturing.

   • Batch Ball Mill:
     In batch ball mills, materials are fed into the mill in batches. After grinding, the mill must be shut down to discharge the product. This type is more suitable for small-scale or custom production.

3. Ball Mills Based on Operational Conditions:

   • Wet Ball Mill:
     In wet ball mills, materials are fed along with water, resulting in slurry as the output. Wet ball mills are primarily used in the ceramics industry.

   • Dry Ball Mill:
     In dry ball mills, materials are fed without moisture, and the output is dry powder. This method is used for materials that do not require slurry.

Factors Affecting Ball Mill Efficiency

• Ball Material and Size:
  Using the appropriate balls improves the mill’s performance.

• Ball-to-Material Ratio:
  The amount of material fed into the mill must be adjusted relative to the volume of the balls.

• Grinding Time:
  The duration of grinding affects the level of crushing.

• Temperature and Humidity:
  Environmental conditions can influence the grinding process.

• Rotation Speed:
  Proper rotation speed is crucial for effective grinding and improving the efficiency of the ball mill.

Applications of Ball Mills in Various Industries

In addition to the ceramic industry, ball mills are used in several other sectors:

• Mining Industry: Grinding and micronizing minerals such as iron oxide and silica.

• Chemical Industry: Grinding and blending chemicals.

• Pharmaceutical and Food Industries: Pulverizing specific materials.

• Recycling Industry: Crushing recycled materials.

Summary

The ball mill is a key piece of equipment in the ceramic tile industry, playing a crucial role in preparing raw materials after the crushing stage. This machine uses special balls to grind materials, providing a uniform slurry for subsequent stages in the production of ceramic tiles.

Ball mill performance depends on factors like rotation speed, ball material and size, material formulation, grinding time, and environmental conditions. There are various types of ball mills based on axis direction, material feeding and discharging methods, and operational conditions, each suitable for different production needs in industries like ceramics, minerals, chemicals, and even pharmaceuticals.

Selecting the right type of ball mill, ball material, and operational conditions can have a significant impact on the quality and efficiency of the production process. Therefore, understanding the performance and features of this device is crucial for optimizing production processes, especially in the ceramic tile industry.