What Is Ball Mill?
Ball mill is a very welcoming grinding equipment. It uses the friction between the material and the steel ball or steel column and the rotation of the drum itself to promote the grinding material to reach the ideal particle size, to facilitate the classification and flotation operations in the subsequent process. The equipment adopted new aircraft, new technologies, and new concepts, which makes the ball mill possess more advantages and characteristics, such as large production capacity, high efficiency, environmental protection, non-pollution, and simple operation. Now, the ball mill is widely used in ore dressing, building materials, metallurgy, cement, glass, the chemical industry, and other fields, as well as gold, iron, molybdenum, glass, quartz silicate products, and other materials have a good grinding effect, now it is one of the most popular types of equipment in the mining industry.
Ball mill structure
- The ball mill consists of the feeding part, the discharging part, the rotating part, the transmission part (reducer, small transmission gear, motor, electric control), and other main parts. The hollow shaft is made of cast steel, and the lining can be removed and replaced. The large gear is adopted casting hobbing to process, and the cylinder inserts with a wear-resistant lining plate, which has good wear resistance. The machine has stable and reliable operating performance.
- The main frame of the ball mill consists of a cylinder, which inserts with a lining made of wear-resistant materials, a bearing that carries the cylinder and maintains its rotation, and a driving part, such as a motor, a transmission gear, a pulley, a V-belt, etc.
- As for the parts called blades, they are generally not the main parts. An internal spiral in the feeding port is called the inner spiral blade. There is an inner spiral in the discharge port at the discharge end, which can also be called the internal spiral blade.
- In addition, if we choose the spiral conveyor as auxiliary equipment at the discharge end, there will be parts called spiral blades in the machine, but strictly speaking, it is no longer a part of the ball mill.
- According to the material type and ore discharge mode, dry-type ball mills and wet-type ball mills are available. Energy-saving ball mill adopts a self-aligning double-row centripetal spherical roller bearing with small running resistance and a remarkable energy-saving effect. For the barrel part, added a section of the conical barrel was at the discharge end of the original barrel, which not only increases the available volume of the mill but also makes the medium distribution in the barrel more reasonable. This product is widely used for material grinding in nonferrous metal(copper, gold, silver, lithium ore, etc. ), ferrous metal(Iron), non-metallic ore(graphite, barite, fluorite, kaolin clay, etc.) dressing, and chemical and building materials industries.
During the operation of the ball mill, the materials will load into the cylinder through the hollow shaft at the feed port. When the ball mill cylinder rotates, the grinding body is attached to the cylinder liner due to inertia, centrifugal force, and friction. When the material spins to a certain height, it will fall due to its gravity, and the falling grinding body smashes the materials in the cylinder like a projectile. The material enters the first bin of the ball mill through the feeding device hollow shaft screw evenly. There is a stepped or corrugated lining plate in the storage, which fill with steel balls of different specifications. The rotation of the cylinder generates centrifugal force to bring the steel balls to a certain height and then drop them, producing heavy blows and grinding effects on the material. After the material has reached rough grinding in the first bin, it enters the second bin through a single layer of partition plates. The storage is inlaid with a flat lining plate and contains steel balls for further grinding the material. The powder is discharged through the discharge grate plate to complete the grinding operation.
Dry and wet ball mills
1. The differences between dry and wet ball mills
1) The dry and wet ball mills have different discharge methods
The discharge outlet of the dry ball mill is a straight cylinder type, which adopts grate plate mill tail discharging, and the discharge is uniform; The outlet of the wet ball mill is a trumpet type with a built-in screw device for discharging.
2) Difference in auxiliary equipment
The difference between dry and wet ball mills also differs from auxiliary equipment. Dry-type ball mills will produce dust due to the absence of liquid in the working process, to avoid dust pollution to the environment during the process, it is necessary to add auxiliary equipment such as an induced draft device, dust exhaust pipe, dust collector, etc; The wet ball mill does not need to add auxiliary equipment.
3) Difference in grinding media
As for the difference in grinding media, the dry ball mill only needs to add steel balls.
In addition to steel balls, the wet ball mill also needs to add liquid to participate in grinding. Usually, the proportion is steel ball: material: water=4:2:1. The nature of different materials is different, so the actual steel ball, material, and water proportion will be adjusted, and determined by the experimental test.
4) Different application
The difference between dry and wet ball mills also reflect in the different applications.
The dry ball mill requires that the materials must be dry and cannot contain any water. It applies to materials such as cement, building stone, etc.
That will produce other substances when meeting water; a wet ball mill requires that the material cannot react when it meets water, and most ores are wetly milled.
2. Advantages of dry type and wet type ball mill
Dry ball mill: uniform discharge, low failure rate, no paste grinding, swelling, and other phenomena, no need to add water, saving costs, but sometimes in the grinding processing will form a dead corner, and the materials entering the dead corner are difficult to grind.
Wet ball mill: because there is liquid involved in the grinding process, there is no existing material entering the dead angle grinding, the grinding efficiency is high, the application range is wide, capable of continuous production, and it will not cause environmental pollution by dust. However, the material after wet grinding must be dried, which increases the production cost.
3. Selection of dry and wet type ball mill
- First, consider the nature of the material to check which grinding method it is suitable for. If the material you want to grind is cement, building stone, etc., these materials will react when mixed with water, and we can only choose dry grinding;
- In addition, considering the requirements for the finished product, if the fineness of the finished product is not high, choose dry grinding. If the material fineness is high, choose wet grinding. If the finished product needs to store with powder, choose dry grinding.
- The other is to consider the environment and production costs, and choose dry grinding in dry and water shortage areas. If you do not want to pollute the environment, choose wet grinding.
The above information is the description of the ball mill. The ball mill is widely used in the mineral processing plant, besides, we can also provide other rock crusher machines and mill grinding machines for a complete mineral processing plant like gold, copper, iron, etc. Eastman Technology has a technical team to provide pre-sale and after-sale services. Welcome to inquiring, and get professional guidance!