Filling station miner

1. It can be summarized into three aspects: ore properties, mill structure and operating conditions
(1) the influence of ore properties, feed particle size and proct particle size
a the influence of ore properties on the operation of the mill can be compared and measured by the grindability of ore (that is, the difficulty of grinding ore from a certain particle size to a specified particle size). Different ores have different grindability, which is mainly related to their mineral composition, mechanical strength, dissemination characteristics and grinding ratio. The ore with compact structure, small crystal and high hardness has low grindability, which needs more energy consumption and low proctivity; On the contrary, the coarse crystalline, loose, soft and brittle ore has high grindability, high proctivity of grinding machine and low energy consumption per unit
b feed particle size
the feed particle size of grinding machine has a great influence on the grinding process. The smaller the feed size is, the shorter the grinding time to the specified fineness is, the higher the processing capacity of the mill is, and the lower the unit grinding energy consumption is< However, the appropriate feed size of the mill can only be determined after considering the total cost of crushing and grinding
C proct size
when the feed size and other conditions are the same, the finer the grinding proct, the lower the proctivity of the mill and the higher the unit energy consumption
(2) the influence of mill structure
grinding is carried out in the mill, and the structure of the mill (including its type, diameter, length and liner shape, etc.) has a great influence on the grinding effect< Under the same conditions, the proction capacity of lattice ball mill is 10% ～ 25% higher than overflow ball mill of the same specification
b the diameter and length of the mill
the diameter of the mill directly determines the ball load pressure on the ground material and the impact force of the steel ball falling. The larger the diameter, the greater the pressure and impact of grinding medium on the ore particles, and the higher the working efficiency of the grinding machine
the length and diameter of the mill together determine the volume of the mill, so it also determines its proction capacity. If the length of ball mill with the same diameter increases, its proctivity will increase proportionally
the length of grinding machine also affects the fineness of grinding procts. When the ore quantity is fixed, the longer the mill length is, the longer the ore stays in the cylinder, and the finer the grinding proct size is
C lining plate of grinding machine
because the external energy is transferred to the grinding medium through the cylinder lining plate, which makes it proce the motion state meeting the grinding requirements, the shape and material of the lining plate have a great influence on the working effect, energy consumption and steel consumption of the grinding machine
(3) the influence of grinding operation conditions
the operation factors that affect the grinding process include: grinding medium loading system, grinding concentration, feeding speed, grinding machine speed, return sand ratio, classification efficiency and the addition of grinding aids, etc.
a the influence of grinding medium loading system
grinding medium and its loading system are the prerequisite for obtaining good grinding indexes, Therefore, each concentrator must find out the most suitable medium loading system through instrial proction test according to the characteristics of the ore and the quality requirements of the grinding procts
(a) the shape and material of the grinding medium, as the grinding medium that directly grinds the material, should meet and take into account two requirements: one is to have as large a surface area as possible to provide an appropriate surface in contact with the material to be grinded; The second is to have as much mass as possible to have the necessary energy for grinding materials. It is self-evident that these two requirements must be related to the shape of the medium and the material used
(b) the size and proportion of grinding media are related to the strength of their impact, extrusion and grinding effect on the material in the grinding machine, which directly affects the grinding effect. When determining the medium size, the main consideration is the properties and particle size composition of the ground ore. Taking the ball mill as an example, when dealing with the ore with large hardness and coarse particle size, it needs a larger impact force, so it should be loaded with larger steel balls; When the ore is soft, the feed particle size is small, and the required grinding proct particle size is fine, the smaller steel ball should be loaded to increase the contact surface between the steel ball and the ground material and enhance the grinding effect. The diameter and speed of the mill should also be considered when selecting the medium size. The grinding machine with large diameter and high speed can transfer more energy to the medium, so the medium with smaller size can be used to increase its number and improve the grinding efficiency
the feed of instrial proction grinding machine is composed of different particle sizes, so the grinding medium loaded into the grinding machine should also have different sizes. Only by keeping the quality proportion of medium of various sizes of the mill in line with the particle size composition of the material to be grinded, can good grinding effect be achieved. The experience summed up from long-term grinding practice is that coarse ore particles should be broken with large steel balls, and fine ore particles should be ground with small steel balls. When the quality of steel balls loaded into the mill is fixed, the number of steel balls with small diameter is more, the number of times of each batch of steel balls falling and hitting is more, the grinding area is also large, but the hitting force of each ball is small; The number of balls with large diameter is less, the number of times of each batch of steel balls falling and hitting is less, the grinding area is also small, but the hitting force of each ball is large. The proportioning of steel balls with various diameters loaded into the grinding machine should not only have enough impact force to just break the coarse ore particles in the feed, but also have more striking times and stronger grinding effect to fine the finer ore particles
(c) loading capacity of grinding medium
when the diameter, length and rotation rate of the grinding machine are fixed, the useful power of the grinding machine increases with the increase of the ball loading rate and the proction capacity increases within the range of ball loading rate not exceeding 50%. However, different speeds have different limit ball loading rate. When the ball mill is operated within the critical speed, the ball loading rate is usually 40% - 50%
(d) reasonable addition of grinding medium
the grinding medium itself is constantly worn in the process of grinding materials, and the larger ones graally become smaller ones, and finally are completely worn out or become fragments and discharged from the grinding machine. In order to keep a proper proportion of media with different sizes in the grinding process and keep the media filling rate unchanged, a certain size and quantity of new media must be added to the grinding machine every day to compensate the worn media quality
practice has proved that the grinding effect can be improved by adding several sizes of steel balls in proper proportion
in order to reasonably add steel balls, the total ball load and its particle size composition of the ball mill should be checked regularly on site to understand the wear of steel balls of various sizes, so as to continuously correct the quality and proportion of steel balls added in proction, and graally make the particle size composition of steel balls in the mill keep close to that of the original ball loading. If there are too many broken balls with irregular shape left in the ball mill after wear, the grinding effect will be affected and they should be removed regularly. The cleaning period varies with the material of the ball. Iron balls are usually cleaned once every 2-4 months, while steel balls are cleaned once every 6-10 months< When other conditions remain unchanged, the movement state of grinding medium in the cylinder depends on the rotation speed of the mill. The grinding effect is not the same with different media movement state. When the rotation speed of the mill is low, the medium is mainly in the form of falling motion, and the impact is small. The grinding function is mainly grinding, and the proction capacity of the mill is low, so it is suitable for fine grinding; When the rotation speed is high, the proportion of medium throwing motion is large, and the impact effect is strong. The grinding effect is mainly impact, followed by grinding stripping, which is concive to crushing coarse-grained materials, and the mill has high proction capacity
the suitable working speed of the mill is 76% and 88% of the critical speed respectively. The speed rate of most ball mills manufactured in China is between 75% and 80%, which is slightly lower than the theoretical calculation value. In the actual proction, the appropriate speed of the grinding machine should be determined by long-term proction comparison test. In the comparison, not only the proction capacity of the grinding machine, but also the power consumption, steel consumption and economic benefits
of course, if the proction capacity of the grinding machine can not reach the design output quota, appropriately increasing the speed of the grinding machine is still one of the effective measures to improve the processing capacity of the concentrator. However, with the increase of grinding speed, the vibration and wear of the mill become more and more serious, so it is necessary to strengthen the management and maintenance. On the contrary, if the mill has surplus proction capacity, its speed should be appropriately reced to rece energy consumption, steel consumption and grinding cost
C influence of grinding concentration
grinding concentration refers to the concentration of pulp in the grinding machine ring normal operation, which can be expressed by either the percentage of solid content (by mass) in pulp or the ratio of liquid mass to solid mass in pulp (referred to as liquid-solid ratio concentration). The discharge concentration of the mill is its grinding concentration
the pulp concentration in the mill has a direct impact on the grinding effect of the medium, the flow performance of the pulp itself and the settling speed of the ore particles. When the grinding concentration is high, the buoyancy of the medium in the slurry is large, the effective density is reced, the impact of the falling is weakened, and the striking effect is poor. When the content of solid ore particles in the slurry is high, the slurry viscosity is high, and there are more ore particles adhered around the medium, the probability of medium hitting and grinding ore particles increases, and the grinding efficiency increases. This is because the fine grinding effect of the grinding machine mainly depends on the grinding vibration crack effect when the grinding medium is in circular motion. However, the grinding concentration should not be too high, otherwise the impact force and grinding activity of the medium will be greatly reced, and the grinding efficiency will be reced; In addition, the slurry is too thick, the slurry fluidity is poor, the coarse material sinks slowly, the overflow ball mill is easy to run out of coarse sand, and the lattice ball mill may be blocked, resulting in "bulge". When the pulp concentration is low, the effective density of the medium in the pulp is large, and the impact force is strong when it falls, but the pulp viscosity is low, the ore particles adhering to the surface of the medium are less, the grinding effect is reced, and the wear of the medium and lining plate is increased. At the same time, when the slurry is too thin, the fine ore particles are easy to sink in the overflow ball mill, resulting in more over crushing. Therefore, it is not good if the pulp concentration is too high or too low, and the appropriate grinding concentration should be determined according to the ore properties, feed and proct particle size and medium characteristics. Generally speaking, the grinding concentration should be higher when dealing with ores with coarse feed size, high hardness and high density; When the ore with fine feed size, low hardness and low density is treated, the grinding concentration is lower
d influence of return sand ratio and classification efficiency in grinding cycle
the classification efficiency and return sand ratio in closed-circuit grinding cycle have a great influence on the proction capacity of grinding machine and the quality of grinding procts: that is, the higher the classification efficiency or return sand ratio is, the greater the proction capacity of grinding machine is, and the less the over crushed particles are. At present, the classification efficiency of concentrator is generally 40% ～ 60%, and the return sand ratio of closed circuit grinding is 200% ～ 350%
e influence of feeding speed
feeding speed refers to the amount of ore fed into the mill per unit time. When the feeding speed is too low and the ore quantity is insufficient, the lining plate will be broken by empty medium in the mill, the wear will be intensified, and the proct will be over crushed seriously; When the feeding speed is too fast and the amount of ore is too much, the mill will be overloaded, and there will be the discharge of steel balls, the discharge of large ore blocks and the gushing of pulp, and the grinding process will be damaged
F effect of grinding aids

2.

the particle size of the material to be grinded is large

if the particle size of the material is large, it is difficult to adapt to the impact and grinding effect of the grinding body, and the first bin of the ball mill is forced to load more steel balls to enhance the ability of impact grinding materials. One bin is responsible for crushing, which makes the crushing process unreasonable. The function utilization rate of crusher is high. Increasing the grinding head crushing and recing the grinding particle size can not only rece the energy consumption, but also increase the output

the moisture content of the feed material is too high

when the moisture content of the feed material is too high, the grinding body and lining plate will be adhered to form a "cushion", and the grate plate will be blocked, causing "full grinding". But the lower the water content, the better. It should be kept in a certain range

fineness requirement of the material to be grinded

the finer the fineness requirement of the material to be grinded, the lower the output, on the contrary, the higher the output

3. The st at the exit of crusher equipment is very serious, and the block and powder materials from crusher directly affect the ore conveyor belt. Some substances splash or roll on the ground, and a thick layer of materials is accumulated on the ground. Part of powder materials are in the air, which brings a lot of inconvenience to proction. In this process, the material enters the plate feeder and the plate feeder enters tkpc20. And a hammer crusher, the crusher directly exports ore to the belt machine. Due to the crusher proction capacity is very large, 600 tons per hour, export logistics is also very large, resulting in st and splash
our analysis shows that the root cause of the above phenomenon is the mping caused by the lack of buffer in octagonal flow. Therefore, the following improvements can be made: a temporary garbage can is established between the crusher outlet and the ore belt, and the st collector is temporarily received. Between the temporary Ben, the belt and a valve. Then a material flow control valve is set in the valve. Setting temporary storage is to buffer the influence of large flowing materials; The material flow control valve can stabilize the export logistics; The st collector in the temporary warehouse can make part of the fine powder be treated in the early stage of the temporary storage, rece the outlet st, and also help to improve the service life of the belt. In this improvement, completely solved the st flying and material splashing point to the workshop proction and management, brought great convenience. In the process of crusher work, there may be some other problems, crusher common problems summary and troubleshooting, but also need to pay attention to time, provide crushing equipment efficiency.

4. The critical speed should be considered first; Secondly, the influence of speed rate is considered. The general rule is proportional to the 2.5th power of the cylinder diameter. The cylinder length determines the particle size characteristics of grinding materials (that is, the probability and time of medium impact), which should be determined by grinding experiments
in the actual proction, the working speed of grinding machine has a wide range. The general rule is that the rotation speed of rod mill is about 10% lower than that of ball mill of the same specification, and in ball mill, the rotation speed of small diameter ball mill is higher than that of large diameter ball mill; The working speed of the mill used for roughing is higher than that of the fine mill. At the same time, the proctivity, energy consumption and steel consumption of the mill should be taken into account when determining the optimal speed of the mill. The practice shows that the best rotation rate is 76% ～ 88% in order to improve the proctivity per unit volume; In order to save energy and steel consumption, the best speed rate should be 65% - 76%. Moreover, the proctivity of unit energy consumption can be improved by appropriately recing the rotating speed
relationship between filling rate and rotation rate: the higher the filling rate of ball mill, the higher the rotation rate needed to reach the maximum useful power. With the increase of rotation rate to a certain extent, the steel ball will change from dropping to dropping, but the transition point varies with the filling rate. The higher the filling rate is, the higher the rotation rate is.

5. The electric separation process of gravity separation is through roughing of gravity separation, using spiral washer, shaker, cone concentrator, and then using roller electric separator to further gather the concentrate after gravity separation
the magnetic separation process of gravity separation focuses on the shaker roughing for gravity separation and the dry magnetic separator cleaning for magnetic separation. The process is aimed at raw ore
titanium ore flotation process: titanium ore beneficiation equipment mainly includes PE jaw crusher, PEX jaw crusher, electromagnetic vibration feeder, ball mill, spiral classifier, flotation machine, thickener, filter and dryer.

6. Mining enterprises are generally recognized as high-risk instries. The working environment is hard, and the probability of casualty accidents is much higher than other jobs. Although the state has adopted very strict regulatory measures, mining enterprises have also made great efforts to constantly improve and optimize the working environment, improve the level of mechanization and automation, and implement standardized and standardized operations, However, in recent years, mine casualties are still high, and serious accidents occur one after another. The reasons are driven by economic interests, and more of them are insufficient investment, incomplete facilities, low quality of personnel and poor quality; Three violations & quot; It's caused by
I. characteristics of casualty accidents in mining enterprises
harmfulness. The occurrence of accidents will cause varying degrees of harm and loss in terms of people, money and materials. At the same time, it will also have a certain impact on social stability, economic development and family happiness. Understanding this feature will improve people's sense of social responsibility and economic responsibility for safety
risk (precursor). Before the accident, the state of the system (human, machine, environment) is unstable, that is, there is an unsafe state, that is, the potential accident. Understanding this, we can prevent the paralysis of lax thinking and complacency, and take corresponding corrective measures as soon as possible to prevent the occurrence of accidents
repeatability. That is to say, the occurrence of accidents has the characteristics of repetition. Mastering this feature will play a positive role in formulating the corresponding preventive measures and preventing the recurrence of similar accidents. At the same time, it also requires people to adhere to & quot; Three not let go & quot; Principle
regularity. The time and place of the accident and the severity of the accident consequence are accidental, but we can find out the regularity of the accident through the analysis of the accident statistical data, so as to provide a strong basis for formulating the correct preventive measures
preventability. Any accident can be prevented as long as we take positive preventive measures correctly and timely and strive to create a good safe proction environment. To realize this, it is helpful for us to strengthen our faith and prevent casualty accidents< 2. Types of mine casualty accidents
mine casualty accidents are mainly concentrated in object strike, roof fall and rib spalling, falling from height, collapse, mechanical injury, vehicle injury, etc. the cause analysis of national non coal mine casualty accidents in 2007 is shown in the figure< According to the scope of roof fall and the number of casualties, it can be generally divided into three types: large roof fall, local roof fall and loose rock fall. Large roof fall usually occurs in the mining of sedimentary minerals, but rarely in metallurgical mines. Local roof fall and loose rock fall are collectively referred to as roof fall accidents
this kind of roof fall accidents often occur in the following situations: in the working face with broken roof; In the working face where the bedding, joints and faults are relatively developed and easy to be separated; In the mine, ultra deep mine, blasting ventilation to eliminate improper working face
the occurrence of roof fall accidents is generally related to many factors such as mine geological conditions, proction technology, organization and management. According to the accident classification statistics, 45.6% of the accidents were caused by proction organization and management, 44.2% by material and technology, and only 10.2% by risk-taking operation< (1) proction organization and management
1. Unreasonable selection of mining methods
unreasonable selection of mining methods is a major cause of roof fall accidents
2. Unreasonable roof support method
another major cause of roof fall accident is unreasonable support method or untimely support in working face or large section driving. When the roof rock near the working face is relatively broken and the structure is relatively developed, the support method is unreasonable or the support is not timely, which is extremely flammable and explosive, resulting in roof falling or spalling, causing accidents
3. Improper pumice treatment
most of the loose stone caving in the roadway occurs within 10 meters from the working face, and most of the loose stone caving in the stope occurs when the roof of the stope is not too high
improper handling of pumice, unskilled removal technology, poor inspection, carelessness or even no inspection are one of the causes of roof fall accidents. Most of the casualties caused by improper handling of pumice are caused by the lack of comprehensive and detailed inspection of the working face top before pumice handling, improper standing position and unskilled technology of the removal workers
4. Improper use of protective equipment
when working in the mine, roof fall accidents are often enlarged e to incorrect use of protective equipment< Personnel management can't keep up with
first, there are many new workers in the mine, they don't understand the underground working environment, and they lack the training of safety knowledge and skills, so they can't connect the old with the new, and they can't timely and effectively & quot; Knock on the gang and ask the top & quot; And cause an accident
Second, the underground management personnel do not pay attention to the roof management, and there is no effective roof management method and supervision and restraint mechanism, so that the roof management is lax, and the small roof fall accidents without casualties are continuous, and the roof fall accidents with casualties are inevitable< (2) preventive measures for roof fall accident
1. Timely adjust mining technology, ensure reasonable exposure space and mining sequence, and effectively control ground pressure
it is necessary to strengthen the experimental research of mine geological work and mining methods, continuously improve the original design of mining methods, find out the efficient and safe mining methods suitable for different geological conditions of the mine, increase the mining intensity and deal with the goaf in time. In order to control the stability of the stope roof, there must be a reasonable mining sequence, so the mining sequence of two adjacent groups of veins should be determined reasonably; According to different geological conditions and mining methods, the technical indexes such as the exposed area of stope and the height of goaf should be strictly controlled so that the stope can be completed ring the period of stable ground pressure
2. The inspection, observation and treatment of roof should be strengthened to improve the stability of roof. The inspection and treatment of roof loose stone is a regular and very important work. It is necessary to fix a special person to work according to the specified system, so as to ensure the safety of roof proction and prevent the occurrence of roof loose stone falling accidents. For some dangerous stopes, scientific methods should be used to observe the roof as far as possible under the conditions of technology and economy. At present, optical stress meter, geophone and rock movement observation are the most economical and convenient observation methods in China. It is necessary to observe and explore the law of rock movement of different rocks and grasp the roof condition scientifically. It is necessary to deal with the unstable working roof in time, and take scientific and effective measures (such as shotcrete and anchor support) to prevent roof fall
3. Scientifically and reasonably arrange the position, specification, shape and structure of the roadway and stope
it is necessary to avoid arranging the roadway engineering near the geological structure line, because the pressure perpendicular to the geological structure line is the biggest, which is the main factor of rock mass change and fracture
it is necessary to avoid the layout of roadway engineering near the weak surface of geological structure such as fault, joint, fracture zone in stratum, argillaceous interlayer, etc. Because the projects arranged in these places are more prone to roof fall. If the roadway engineering must pass through these zones, corresponding supporting measures or special construction schemes should also be adopted
the shape and structure of roadway and stope should meet the requirements of surrounding rock stress distribution as far as possible. Therefore, the roof of roadway and stope should be arched as far as possible. Because the secondary stress of surrounding rock is not only related to the original rock stress and lateral pressure coefficient, but also related to the shape of roadway. When the arch shape is adopted, the construction is not difficult, the roof pressure is not too concentrated, and the roof stability is good< Strengthen the roof management and improve the technical level of roof management
first, strengthen the safety ecation and the training of safety technology knowledge, improve the technical level of safety management personnel at all levels, and establish & quot; Safety first & quot; The roof management system of group inspection, group prevention and group governance should be established. Special crowbar shall be provided at each working face, special person or part-time manager shall be set up to be specifically responsible for the risk elimination work of each working face, warning signs shall be set up, shift handover system shall be well done, and management of key hazard source points shall be carried out
the second is to summarize the experience and lessons of roof management in combination with the actual situation of the mine, and formulate a complete set of roof management standards for roadway construction from the provision of geological data, roadway design, roadway maintenance technology and construction management, so as to provide technical support for scientific and effective roof management< (3) self rescue and mutual rescue in case of roof fall
1. Self rescue measures in case of roof fall
(1) quickly retreat to a safe place. When it is found that there is a sign of roof falling in the working place, and it is difficult to take measures to prevent the roof falling, the best disaster avoidance measure is to leave the dangerous area quickly and retreat to a safe place
(2) when in danger, you should stand close to your body or go to the wooden crib to avoid the disaster. From the actual situation of roof fall in mining face, it is very rare that the roof fall along the rock wall. Therefore, when there is no time to retreat to a safe place in case of roof fall, the person in danger should stand close to the rock to avoid the disaster, but pay attention to the wall to help hurt people. In addition, the pillars may be broken or knocked down when the roof falls, but it is impossible to crush or push down the qualified wooden stacks under normal circumstances. Therefore, if the person in distress is close to the wooden crib, he can withdraw to the wooden crib to avoid the disaster
(3) send out a call for help signal immediately after distress. The main injuries of roof fall are smashing, burying or blocking. After the fall is basically stable, the person in danger should immediately use the methods of calling and knocking (if the material or rock block may cause a new fall, it can not be knocked but can only be called) to send out regular and uninterrupted call for help, so that the rescue personnel and evacuation personnel can understand the situation of the disaster and organize forces for rescue
(4) people in distress should actively cooperate with external rescue work. People who are buried and pressed by rocks and materials after roof fall should not panic. When conditions do not permit, they should not resort to violent struggle to get out of danger, resulting in the expansion of the accident. People blocked by roof fall should maintain their own safety in an organized way at the place of distress, build escape channels, cooperate with external rescue work, and create good conditions for early escape
2. Measures for rescuing people in danger of roof fall
(1) to ensure the safety of rescue personnel. The rescue work should be carried out under the command of the leaders and experienced workers in the disaster area. The rescuers should check the supports near the roof fall site, and deal with the damaged, twisted and deformed columns immediately to ensure the safety of the rescuers, and set up a smooth and safe exit
(2) support the roof fall according to local conditions. According to the situation of roof collapse, on the premise of ensuring the safety and convenience of rescue personnel, the roof fall should be supported according to local conditions. In case of partial roof fall in mining face, the method of digging out beam socket, hanging metal roof beam, or digging out beam socket, erecting monocular shed can be used. The gap on the shed beam should be set up with wood, and the small wooden stack should be connected to the top, and the back should be inserted tightly to prevent the roof fall from further expanding
(3) rescue the buried personnel. After checking that the erected support is firm and reliable, a special person should be assigned to observe the roof, so as to clean up the falling rocks near the buried personnel, until the personnel in danger are rescued from the buried area. In the rescue

7. Performance characteristics of rod mill:
the particle size characteristics of rod mill procts are related to the situation of rod grinding ore. When the bar strikes the ore, it first strikes the coarse particles, and then grinds the smaller particles, thus recing the risk of over crushing. When the bar rotates and rises along the liner plate, coarse particles are sandwiched between them, like bar screen, which allows fine particles to pass through the cracks of the bar. This is also concive to crushing coarse particles and concentrating coarse particles in the place where the grinding medium strikes. Therefore, the proct of rod mill is more uniform and the over grinding is lighter

difference:
1. Grinding medium
(1) ball mill: the grinding medium in the mill is mainly steel ball or steel section. This kind of mill is most commonly used
(2) rod mill: steel rods with a diameter of 50-100 mm are installed in the mill as grinding medium. The ratio of length to diameter of rod mill is generally 1.5-2
(3) baseball mill: this kind of mill usually has 2-4 bins, in the first bin, cylindrical steel bars are loaded as grinding medium, and then each bin is loaded with steel balls or steel sections
the ratio of length to diameter of the ball mill should be about 5, the ratio of the length of the bar bin to the effective diameter of the mill should be between 1.2 and 1.5, and the length of the bar should be about 100 mm shorter than that of the bar bin, so as to facilitate the parallel arrangement of steel bars and prevent cross and disorder of bars
(4) gravel ball mill: the grinding media in the mill are gravel, pebble, ceramic ball, etc. Granite and porcelain are used as lining plates. Used in white or color cement and ceramic proction< (1) steel rods with diameter of 50-100 mm are commonly used as grinding medium in rod mills, while steel balls are used as grinding medium in ball mills. The length of steel rods is 25-50 mm shorter than the cylinder, and high carbon steel with carbon content of 0.8% - 1% is often used; The loading capacity of the rod is about 35% - 45% of the effective volume of the rod mill. When observed with naked eyes, the horizontal plane of the rod is about 100-200 mm below the cylinder centerline
(2) the ratio of length to diameter of rod mill cylinder is generally 1.5-2.0, and the inner surface of lining plate on end cover should be vertical plane. The purpose is to prevent and rece chaotic movement, bending and breaking of steel rod in cylinder, and ensure regular movement of steel rod. The ratio of cylinder length to diameter of ball mill is small, and in most cases, the ratio is only slightly greater than 1
(3) rod mill adopts overflow and open discharge instead of grid plate discharge; The diameter of the hollow journal at the discharge end is generally larger than that of the ball mill of the same specification. The rotational speed of the cylinder of the rod mill should be lower than that of the ball mill of the same specification, so that the medium in the cylinder can work in the state of dropping down
3. Proction capacity
both ball mill and rod mill are important mine mills. Their proction capacity is related to the following factors: grindability of ore, particle size of feed and final proct, type and size of mill, shape of liner, shape, size, proportion, hardness and density of grinding medium, working speed of mill, filling rate of grinding medium, grinding concentration, The amount of return sand and the working efficiency of classification equipment. Because there are many factors that affect the proction capacity of the grinding machine, and the factors vary greatly, there is no theoretical formula to accurately calculate the proction capacity of the grinding machine. Therefore, the proction capacity of grinding machine is generally calculated by approximate method according to empirical formula. There are two commonly used calculation methods: grinding machine according to the unit proction capacity of ore meter calculation method (also known as volumetric meter algorithm) and grinding power calculation method. The volume calculation method is commonly used in China, which is more convenient< (1) rod mill is often used in gravity separation or magnetic separation plant of tungsten tin ore and other rare metal ore in order to prevent the harm caused by over crushing
(2) in some cases, it can replace 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 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.

8. 1. Enter the maintenance program: total clear key - 107 (number key) - clear / pause key (more than three seconds)
2. Select 2-209-2: powder filling rate coefficient
3. You can set it according to your actual situation.

9. In order to distinguish from autogenous mill, the mill that needs to add metal medium (ball or rod) is called conventional mill, such as ball mill and rod mill. Each of these grinders has its own characteristics. How to select the appropriate grinders according to the requirements of mineral processing technology on the particle size of the selected materials and the properties of the raw ore and the characteristics of various grinders is of great significance to obtain higher grinding efficiency and improve the economic effect of mineral processing. The main features and application scope of ball mill and rod mill commonly used in concentrator are as follows:
1) lattice ball mill. Due to its unique grid plate and the existence of the lifting bucket in the fan-shaped chamber, the low-level forced ore discharge is realized. The ground ore particles can be discharged in time, and the qualified particles will not stay in the ball mill for too long, so the over crushing phenomenon is light, the grinding speed is fast, and the efficiency is high
e to the low pulp surface and less ore in the mill, coupled with the "isolation" effect of grid plate, on the one hand, a higher medium filling rate can be used to increase the ball loading, and an appropriate amount of small balls can be added. On the other hand, after the ball is lifted to a certain height, the ball has a larger falling height at a relatively low pulp surface, so the impact effect of medium ball is stronger, The grinding effect is good
e to the fast discharging speed and the short residence time of ore, the ground ore can be discharged into the classifier quickly from the mill for classification into the follow-up operation, so that the mill can supplement more raw ore, and at the same time, the dense particles will not gather in the mill, so as to rece the over crushing and improve the proctivity. Compared with the overflow type of the same specification, the proctivity is 10% ～ 25% higher. This kind of mill is suitable for the first stage grinding of one stage rough grinding or two stage grinding, and can also be used to grind easily crushed and soft ores< 2) overflow ball mill. The discharge of the mill depends on the fact that the diameter of the hollow shaft at the discharge end is slightly larger than that at the feed end, resulting in a certain inclination of the pulp in the mill towards the discharge end. When the pulp surface height is higher than the lowest inner diameter of the discharge port, the pulp will overflow out of the mill. This is a non forced high level discharge, discharge speed is slow, so the retention time of ore in the machine is long, the effective role of the medium is low, so overflow type ball mill over grinding is serious, the processing capacity is also lower than the same specification of lattice type. It is generally suitable for fine grinding or second grinding in two-stage grinding
3) rod mill. The medium in the rod mill is steel rod, so after falling horizontally, it contacts with the surface line of ore material and has selective crushing effect, that is, crushing according to the particle size from large block to small block in turn. Therefore, the over grinding is light and the particle size of grinding procts is uniform, which is suitable for coarse grinding or heavy concentration plants requiring over grinding of grinding procts.

10. The critical speed should be considered first; Secondly, the influence of speed rate is considered. The general rule is proportional to the 2.5th power of the cylinder diameter. The cylinder length determines the particle size characteristics of grinding materials (that is, the probability and time of medium impact), which should be determined by grinding experiments. In the actual proction, the working speed of grinding machine has a wide range. The general rule is that the rotation speed of rod mill is about 10% lower than that of ball mill of the same specification, and in ball mill, the rotation speed of small diameter ball mill is higher than that of large diameter ball mill; The working speed of the mill used for roughing is higher than that of the fine mill. At the same time, the proctivity, energy consumption and steel consumption of the mill should be taken into account when determining the optimal speed of the mill. The practice shows that the best rotation rate is 76% ～ 88% in order to improve the proctivity per unit volume; In order to save energy and steel consumption, the best speed rate should be 65% - 76%. Moreover, the proctivity of unit energy consumption can be improved by appropriately recing the rotating speed. The relationship between filling rate and rotation rate: the higher the filling rate of ball mill, the higher the rotation rate needed to reach the maximum useful power. With the increase of rotation rate to a certain extent, the steel ball will change from dropping to dropping, but the transition point varies with the filling rate. The higher the filling rate is, the higher the rotation rate is.