Large ball mill Introduction

Large ball mill is used mainly used for crushing and grinding of different kind of materials, it is widely used in cement, ore dressing, building materials, refractory materials, chemicals, glass ceramics and other production industries. Tongli offers various specifications and models of large ball mills suitable for various materials such as cement clinker, gold ore, iron ore, copper ore, pyrrhotite, magnetite steel slag, lime, quartzite, bauxite, bluestone, kaolin, lithium ore (spodumene, lepidolite), calcite, magnesite, quartz sand, water slag, slag, aluminum ash, fly ash, glass, barite, potassium feldspar, alumina, granite, clinker, bauxite, etc. Tongli has rich experience in manufacturing large ball mills, the diameter ranges from 2 meters to 8 meters.

Lae ball mill structure

Mill Shell: The foundation of the large ball mill, the mill shell, is a cylindrical structure made of premium-grade steel. Tongli heavy machinery is equipped with a large annealing furnace of 6.5x6.5x20m and a 6.5x6.5x20m large sandblasting room, which can conduct overall heat treatment and sandblasting on the ball mill to ensure the service life and appearance of the ball mill.

Trunnion: The trunnion (hollow shaft) of the large ball mill is a steel casting manufactured in our metal casting workshop. It mainly plays the role of supporting and connecting the shell, it is the passage for the material to enter and exit. When the ball mill is operating, the trunnion is floating on the bearing bush with the aid of the forced high pressure lubrication system.

Bearing Bush: Large ball mill bearing bush ensures the smooth rotation of the ball mill and empowers the ball mill to maintain optimal grinding conditions. It is equipped with a forced lubrication system and also cooling system. It has alloy surface and 3 rolling rods on the bottom to make sure when the ball mill trunnion moves, the position of the bearing bush can be adjustable.

Transmission connection: Tongli’s large ball mill is equipped with a transmission connection, which is welded on the cylinder and machined together with the ball mill shell on our 5x18m CNC controlled horizontal lathe to avoid assembly errors and ensure the concentricity of the ball mill.

Girth Gear: The large ball mill girth gear is a large gear ring encircling the ball mill, usually mounted on the shell of the ball mill. It is driven by a pinion gear, and together they form the primary drive unit to rotate the ball mill. The girth gear is casted and machined Tongli, the quality is assured.

Hood Cover: The discharge hood of the large ball mill is installed at the discharge end of the ball mill, and there is a screen inside. After grinding, the material with a qualified size will enter the discharge hood through the screen and enter the next process. There is a vent on the upper part of the discharge hood, and a discharge funnel on the lower part.

Diaphragm: The ball mill Diaphragm (compartment plate) is fan-shaped plate or bow-shaped grate plate fixed in the large ball mill with bolts. Its function is to divide the ball mill into two or more chambers, the material moves to the next compartment through the openings on the grate plate. The function of the compartment plate is to prevent the grinding media running from one compartment to another compartment, so that the materials can be reasonably finely ground.

Liner: The function of the liner is to protect the shell of the ball mill and the trunnion, some special-shaped liners can also design to lift the grinding media to a certain position. According to the shape of the liner, it can be divided into flat liner, beaded liner, corrugated liner, ribbed liner, stepped liner, etc.

Rod ball mill transmission: Central drive ball mill refers to the arrangement of the driving mechanism for the mill. In a central drive configuration, the motor and gearbox are positioned at the center of the mill, usually between the grinding chamber and the mill shell. This design is in contrast to an edge or end drive configuration where the motor and gearbox are situated at one of the ends of the mill. Central drive transmission systems typically involve a motor that powers a gearbox, which then transfers the rotational energy to the mill's main shaft. The central drive design can provide advantages in terms of power distribution and efficiency compared to other drive arrangements. It can also offer better control over the mill's operation.

PLC control system: A PLC is a digital computer-based system that is designed to control various industrial processes automatically. In the context of a ball mill, a PLC is used to monitor and control parameters such as temperature, rotation speed, air flow, fuel flow, and other critical variables that affect the performance of the ball mill and the quality of the products being processed. 

Design principles of large ball mill

Large ball mill closed-circuit system can effectively reduce the phenomenon of excessive grinding of materials. The qualified finished products are pumped out by the O-Sepa powder separator and sent to separate rooms for spraying. The dust collector collects the finished product, and the material powder whose fineness does not meet the requirements is still ground in the Large ball mill until it reaches the fineness required by the process. At the same time, the raw materials can lose part of the heat through transportation and powder selection. When the coarse powder is re-grinded, the temperature inside the mill can be reduced, which is beneficial to increase the output of the mill and reduce the power consumption of the mill. The closed-circuit system can increase the output by 15-25% compared with the open-circuit system, and the product fineness can also be controlled by adjusting the grading equipment, which is easy to operate.

Structure design: The material is directly fed into the coarse grinding chamber in the barrel of the large ball mill with the feeding chute in the feeding device, and the material is crushed under the impact grinding action of the grinding body (steel ball) with a large average diameter, and is crushed to a certain particle size through the gap between the coarse sieve plates of the compartment plate, enter the combined compartment plate, and the grinding body of the coarse grinding compartment is blocked by the compartment plate.

Advanced manufacturing Equipment: Tongli has over 100 set of large-scale mechanical processing equipment, especially a 5.3x18-meter fully numerically controlled horizontal lathe to ensure the processing accuracy and concentricity of the ball mill.

Heat treatment: Tongli heavy machinery is equipped with a large annealing furnace of 6.5x6.5x20m and a large sandblasting room, which can conduct overall heat treatment and sandblasting on the ball mill to ensure the service life and appearance of the ball mill

Process Control: Tongli has its own metal casting foundry, starting from the raw material to the finished product, Quality in every detail, from start to finish.

Lubrication system: Tongli ball mill is equipped with force lubrication system, there is an oil station equipped for the transmission part, another oil station for the gearbox to ensure smooth operation and prolong service life of the ball mill.

Cooling system: The main bearing bush is equipped with a water cooling system, and a cooler is also installed in the lubrication system to forcibly cool the lubricating oil.

Transmission connection: Tongli’s ball mill is equipped with a transmission connection, which is welded on the cylinder and machined together with the ball mill shell to avoid assembly errors and ensure the concentricity of the ball mill.

Specifications of large ball mill

Note: * Mill diameter refers to the inner diameter, while the mill length refers to the effective grinding length.

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Zhejiang Tongli Heavy Machinery Manufacturing Co., Ltd (Formerly known as Tongxiang Coal&Mining Machinery Factory) established in year 1958 is a member of the Chinese National Building Material Machinery Association. Tongli is on the vendor list of designated production enterprise of the Ministry of Coal Industry. ISO9001、ISO14001、ISO45001 certified, accredited as High-tech & new technology enterprise of Zhejiang Province. With 65+ years of experience, Tongli has earned first class R&D and manufacturing capabilities, dedicated to provide satisfactory manufacturing equipments for global customers.   

Industry Knowledge extension:

What is the difference between center drive ball mill and edge drive ball mill?

In terms of processing and manufacturing, the girth gear of the edge drive ball mill has a large diameter, which is difficult to manufacture and takes up a large space, but has low precision requirements; the center drive has a compact structure and a small footprint, but has high manufacturing precision requirements, and the requirements for materials and heat treatment higher. In terms of price, the center transmission is higher than the edge transmission because of the high processing accuracy. In terms of maintenance, the parts of the edge drive are scattered compared with the center drive, there are more oil supply points and more check points, the operation and inspection are inconvenient, the wear is fast, and the service life is short;

What is the difference between Open-circuit and closed-circuit ball mill?

Closed-circuit grinding refers to that in the grinding operation, the material is fed into the mill and then classified after one grinding, the ore with unqualified particle size is returned to the mill for regrinding, and the ore with qualified particle size is sent to the next stage. The closed-circuit mill has a high crushing rate, and the quality of the obtained product is high. At the same time, the output of the closed-circuit production is relatively large, but its disadvantage is that the production process is relatively complicated and the input cost is high.The production process of the open circuit mill is relatively simple, and the input cost is low. And its disadvantage is that it has low production efficiency, because the qualified fine powder cannot be removed in time, so it produces a large energy consumption during production.

What is the difference between ball mill and vertical roller mill?

Both ball mills and vertical roller mills plays a vital role in the cement grinding plant. Ball mills are versatile and cost-effective, suitable for various materials and simple to maintain. On the other hand, vertical roller mills offer superior energy efficiency and particle size control, making them ideal for cement and ore grinding applications. The choice between the two depends on specific requirements, budget constraints, and technical expertise.

How to install A Ball mill?

The first step of ball mill installation is to Install the base frame of the ball mill. The base installation uses a large number of metal partitions as base pads, prepare metal partitions with different thicknesses in advance for backup. After the base is installed, the worker can adjust the position of the base and the number of partitions according to the actual situation, the width of the partition cannot be less than 80mm, and the external exposed part should exceed at least 10mm In order to move the baffle, after the location of the baffle is determined, a welding operation is required. After the ball mill chassis is installed, it is necessary to accurately measure the levelness and level of the chassis with a spirit level and a tracking instrument.