What's the meaning of discharging ore around dry rod mill
rod mill is a kind of mill in which the grinding body is steel rod. Rod mill generally adopts wet overflow type, which can be used as first-class open circuit grinding. It is widely used in first-class grinding of artificial sand, concentrator, chemical plant and power department. The mill is mainly composed of motor, main recer, transmission part, cylinder part, main bearing, slow transmission part, feeding part, discharging part, ring seal, playful voice station, big and small gear spray lubrication, foundation part, etc. The main recer has parallel shaft and hard tooth surface. The rod mill is an asynchronous motor connected with the pinion through the recer, which directly drives the peripheral big gears to decelerate and rotate, and drives the rotary part to rotate. There is a suitable grinding medium steel rod in the cylinder. Under the action of centrifugal force and friction, the grinding medium continuously enters the cylinder from the feeding part and is crushed by the moving grinding medium, And through the overflow and continuous feeding force, the proct is discharged out of the machine for the next process. Its working principle, structure, type, grinding medium, application, installation and installation precautions are introced in detail.
There are three kinds of general rod mills:
1
2
3
overflow type rod mill is the most widely used, and the particle size of the proct is finer than the other two. It is generally used to grind the crushed proct and then supply it to the ball mill. The particle size of the proct is 2-0.5mm
the end peripheral discharge rod mill is generally used for dry grinding, and the proct particle size is relatively coarse. This kind of rod mill can also be used for wet grinding. High gradient and good flow rate can be obtained by using peripheral discharge rod mill, and the proct particle size is 5-2mm
the rod mill for discharging ore around the center can be used for wet and dry type. The particle size of the proct is coarser, and the material is fed from both ends of the rod mill. The grinding process is short, and the sand with high gradient and too fine proct is discharged quickly. This kind of rod mill is mainly used in aggregate instry to proce sand and stone
in order to prevent disorder and entanglement of grinding rod, it is generally recommended that the ratio of rod mill length to inner diameter be 1.4 to 1.6. When the ratio is less than 1.25, the possibility of entanglement increases sharply, so it should not be less than 1.2. When the diameter of the rod mill is greater than 3.8m, the working efficiency and quality of the rod mill should be carefully considered
the material of the rod mill is generally fed into the hopper. In order to obtain normal flow, the bottom of the feeding hopper should be 1.5m higher than the center of the rod mill. The rotational speed of the rod mill is generally 60 ~ 68% of the critical speed, not more than 70%. The rotational speed of the bench can make the rod mill roll in sequence. Too high rotational speed makes the rod throw, and too low rotational speed reces the output
the overflow type rod mill can be equipped with a rotary screen at the discharge end to remove the fragments of the grinding rod and catch the large materials running out. The discharge end and outlet can be closed in a small chamber. A door shall be provided at the end of the chamber for loading and unloading the grinding rod
rod mills can be divided into center discharge type (overflow type) and peripheral discharge type (open type). The former is widely used, while the latter has stopped manufacturing.
(1) the diameter length ratio of dry autogenous mill (ball mill) cylinder is large, the cylinder is short, and the diameter of hollow shaft is short. Generally, the diameter of the cylinder is about three times of its length
(2) the end cover is perpendicular to the cylinder, on which there are two rings of annular wave crest lining plates
(3) in addition to flat liner, T-shaped lifting liner with a certain height is also laid on the cylinder at a certain distance,
its main function is to lift the material to a certain height and throw it down when the cylinder rotates, so that the crushed material can obtain enough energy,
much greater than that of the ball mill, and proce impact effect, so that the large block can be crushed
the above are several different aspects of the ball mill of zhengkuang machinery finishing, I hope they are useful to you~~
Because the impact of the ball mill medium is point contact when it is thrown down, the large particles in the coal are easy to escape from the inlet to the outlet, and there are many large particles. On the contrary, the finer coal particles will be over crushed when they are repeatedly impacted by the falling ball, so the 320 mesh pulverized coal is more than the rod mill. The rod mill is characterized by linear contact between rods in the process of movement. Firstly, the larger particles of coal are crushed, which greatly reces the large particles of coal. This selective crushing can rece the phenomenon of over crushing of coal. The ball mill process is also ideal. Its biggest feature is that feldspar and other hard materials are dry powdered by a column mill, and the required mesh number (180-300 mesh) is reached before entering the silo. The investment of this dry milling equipment is about 1.5 million yuan (excluding two section combined ball mill), but its energy saving effect is very significant. Plastic raw materials are still grinded by the original intermittent ball mill and then put into the slurry pool. In this way, feldspar powder and plastic slurry are grinded by two combined continuous ball mill in proportion through different metering methods. The output of this method is very high, up to 80 tons of slurry per hour, and the energy saving is up to 40% - 50%. The automation of feeding and formulation is realized, The uncertainty factors of artificial formula and feeding are avoided. This process is the best choice for enterprises to expand proction. It does not need civil engineering and covers an area of the original workshop
The rod mill is driven by the motor through the recer and the peripheral big gear, or by the low-speed synchronous motor directly through the peripheral big gear to drive the cylinder to rotate. The cylinder
contains a suitable grinding medium steel bar. Under the action of centrifugal force and friction, the grinding medium is lifted to a certain height and falls in the state of throwing or releasing. The grinded material continuously enters into the cylinder from the feeding port, and is crushed by the moving grinding medium, and the proct is discharged out of the machine through overflow and continuous feeding force for the next operation
when 80% of the proct particle size is required to be less than 2.0% to 0.5mm, rod mill is generally used. The maximum particle size of rod mill is not more than 4.7MM, and the minimum particle size is not less than 0.4mm. The feeding particle size of rod mill is 80% less than 20mm to 4mm, and the maximum particle size of feeding can also reach 50mm. Due to the material of the grinding rod and other reasons, the length of the grinding rod should not exceed 6.1 meters, otherwise it will cause bad consequences such as disordered rods. Therefore, the specification of the rod disintegrator has not exceeded 4.6 meters × 3 meters
when the ore is fed into the rod mill, the coarse particles are at the feeding end and the fine particles are at the discharging end: therefore, the rods can not be completely parallel and inclined ring operation, which is one of the reasons why the grinding rods cannot be too long
the crushing ratio of rod mill ranges from 15:1 to 20:1. Most of the conventional crushing and grinding processes in foreign concentrators are composed of crusher, rod mill and ball mill. In China, rod mill is not widely used in concentrators, and the feed particle size of ball mill is relatively high, resulting in high energy consumption, grinding medium consumption and lining plate consumption. Because the grinding rod of rod mill is in line contact, large materials are ground first, which has selective grinding function. Therefore, the proct size range is narrow, the proct size is uniform, the over grinding phenomenon is less, and the grinding efficiency is higher.
The grinding medium of rod mill is grinding rod. It is generally believed that the length of grinding rod should not exceed 7 meters, because too long grinding rod is easy to cause winding. Therefore, the length of rod mill used is not too long, and the diameter of grinding rod is 75 ~ 150 mm
the grinding rod should have enough rigidity and hardness to keep straight without bending ring use, and should not be so brittle that it is not worn to a small enough diameter to break into pieces. However, when worn to a small enough diameter, it should be able to break into small pieces for discharge from the rod mill. If the grinding rod is too soft, it is easy to bend when the cylinder rotates. Bending causes premature damage and winding of the grinding rod. Winding of the grinding rod makes it difficult to clean the mill and wastes time
the website will provide you with the latest and most detailed quotation and technical parameters of different types of equipment,
you can also consult the company. Their service attitude is very good and they will answer all kinds of questions for you< There are three uses of rod mill:
1) rod mill is often used in gravity separation or magnetic separation plant of tungsten tin ore and other rare metal ore to prevent the harm caused by over crushing
2) when the two-stage grinding process is used, if the first stage is from 20-6 mm to 3-1 mm, and the rod mill is used as the first stage grinding equipment, the proction capacity is larger and the efficiency is higher. Because the surface area of a certain weight of rod load is much smaller than that of the same weight of ball load, the proctivity and efficiency of rod mill are lower than that of ball mill in the second stage of fine grinding
3) in some cases, it can replace the short head cone crusher for fine crushing. When dealing with softer or less hard ores (especially those with high viscosity) and grinding 19-25 mm (or even 32 mm) ores to 6-10 mesh with rod mill, the configuration is simpler and the cost is lower than that with short head cone crusher and screen in closed circuit, and the st removal of crushing workshop can be simplified. For hard ores, it may be more economical to use the short head cone crusher to form a closed circuit with the screen. Whether ball mill or rod mill should be used in the design must be determined by making plans according to the specific situation and comparing them
rod mills are widely used in metal and nonmetal mines, water conservancy and building materials departments to grind various ores or rocks
the rod mill is driven by the motor through the recer and the surrounding big gear, or by the low-speed synchronous motor directly through the rod mill through the surrounding big gear to drive the cylinder to rotate. A suitable grinding medium steel bar is installed in the cylinder. Under the action of centrifugal force and friction, the grinding medium is lifted to a certain height and falls in the state of throwing or releasing. The grinded material continuously enters into the cylinder from the feeding port, and is crushed by the moving grinding medium, and the proct is discharged out of the machine through overflow and continuous feeding force for the next operation.