Hey;Due to a problem in our cement mill motor cooling system, temperature of the winding temperature increased to the high limit (120 C), solving the problem of the cooling system will take few days but till that time we don't want to keep the mill stop. What do you think of reducing the filling degree of grinding media in the second compartment of the cement mill to reduce the load (kW)to reduce the motor temp????Best Regard
Due to a problem in our cement mill motor cooling system, temperature of the winding temperature increased to the high limit (120 C), solving the problem of the cooling system will take few days but till that time we don't want to keep the mill stop. What do you think of reducing the filling degree of grinding media in the second compartment of the cement mill to reduce the load (kW)to reduce the motor temp????
The first class manufacurer and suplier of large slip ring motors with fast delivery time and high flexibility. Type: asynchronous slip ring electric motor Power: 160 to 5000kW Voltage: 400V, 690V, 3300V, 6000V, 6600V, 11000V Frequency: 50Hz or 60Hz Number of poles: 4, 6, 8, 10, 12, 16
In the cement production line, we use cement crusher for cement crushing process, then we need cement mill for fine grinding stage. As a kind of cement grinding machine, Cement mill is the equipment used for grinding the hard , nodular clinker from the cement kiln into the fine grey powder that is cement.
Its main function lies in grinding cement clinker (and gelling agent, performance adjusting grinding materials) into suitable particles (by fineness and specific surface area, etc), to form certain particle gradation, increasing its hydration area, accelerating the hydration speed, satisfying the slurry condensation and hardening requirements.
Henan Hongxing Mining Machinery Co., Ltd. is a professional manufacturer of full sets mining equipment including cement mills, stone production line, sand making production line and so on. Besides, we offer the most favorable cement mill price.
Cement ball mill is not only suitable for over-flow grinding, but also applicable for cyclic close-flow grinding together with powder collector. The opportunities and challenges of the cement mill industry co-exsit today, although the overall size of milling machinery manufacturing industry has entered the ranks of the international producing countries, the overall competitiveness and development potential still can't compete with the developed countries. The current domestic high-end users and the basic components for products export mainly rely on imports.
This economic stimulus policy of development can avoid the economic crisis waves, and it makes the development of China's economy and the GDP stabilizing increase steadily. Some basic road and bridge construction of public facilities will bring significant step into the cement ball mill industry which makes cement ball mill industry usher in a new 'spring'. Therefore, the development of cement mill in the future should focus on the revitalization of basic technology and infrastructure components to raise the level of independent development.
Cement mill electric motor 6000V for cement manufacture plant. We design and sell medium and high voltage slip ring motors to customers worldwide. We supply electric motors with a variety of voltages, cooling techniques and big range of power output. For more information on the tech specs of these high-quality electric motors, please contact us directly via email or phone.
Cement mill motors are available in a wide variety. In one location, sales and development are merged. For more information on our existing stock quantities, please contact us. Ours is one of Slovakias largest stocks of its kind. We feel the urge to maintain a large stock of electric motors for our customers. As a result, we can ship orders to the buyers as quickly as possible. We also understand that each procedure has its own set of conditions, as well as the fact that every customer is different. As a result, we will build custom electric motors to meet the unique specifications. Simply tell us what youre searching for, and well do as much as we can to help you find it.
We design electric motors for cement factories, coal plants, refineries, waterworks, major industrial firms in a number of industries, and more. Our medium and high voltage slip ring motors are among the finest on the market at the moment. Theyre constructed with cutting-edge technology and high-quality components that will last for ages. An image gallery of one of these amazing machines can be found on this page. If you have any doubts or reservations about our slip ring motors, please do not hesitate to contact us. We can be reached by phone or email. Our experienced workers will gladly respond to questions you may have and lead you through the process of picking your new slip ring motor.
Slip ring motors with a voltage of 6000 volts or other are available. We have many large slip ring motors on site. We go to great lengths to make sure our clients are pleased. Well modify the motor voltage to meet your requirements. The design and size of the motor frame can be customized. We may also include a number of accessories upon request. Your motor will be really one-of-a-kind, designed to your exact specifications.
Many young engineers consider cement plants pretty complicated because of their weird technology. The reason probably lies in the fact that you cannot understand all those technologies unless you worked in such a plant and saw all processes from scratch. However, this article will try to bring down a few essential production steps in the cement plant, as well as the power supply and distribution in cement plants.
Before we dive into details, note that this article assumes that you are already familiar with the basic terms of cement plant equipment and process. But, lets first describe how the cement plant works after all.
The most important raw materials for making cement are limestone, clay and marl. These are extracted from quarries by blasting or by ripping using heavy machinery. Wheel loaders and dumper trucks transport the raw materials to the crushing installations.
The crushed material is transported into the raw material storage of the cement plant by conveyor-belts, cableways or railways and also in exceptional cases with trucks. Once there it is stored in blending beds and homogenised.
After burning, the clinker is cooled down and stored in clinker silos. From there the clinker is conveyed to ball mills or roller presses, in which it is ground down to very fine cement, with the addition of gypsum and anhydrite, as well as other additives, depending on the use to which the cement is to be put.
Power distribution system of a cement plant begins with the substation of the grid where power is received and ends with individual drives and points of usage. It is a large network consisting of elements like: distribution transformers, MV/LV control panels, individual distribution switchboards and motor control centres (MCCs), switchgears for safety, regulation and metering of power used at various points, motors and their controlgear, power and control cables, lighting, earthing and other components of the system.
Variable speed motors can be either AC or DC with ratings ranging from fractional kws, for motors for dampers, valves etc., to several hundred kws for motors for fans. All these motors are to be supplied with electric power at voltage and frequency and type of circuit for which they are designed.
Depending on the country, frequency of power supply can be 50 or 60 cycles. Voltage of transmission could be as high as 222 KV or 132 KV for large capacities and 66 KV, 33 KV or 11 KV down the line depending on MVA capacity of the substation.
The voltage of generation itself would be say 6.6 KV. It is stepped up for transmission; longer the distance over which power is to be transmitted higher the voltage oftransmission to minimize losses in transit.
The whole system of distribution of power can be shown pictorially as a grid linking the several generating stations in a State. Grid ensures that power is assured to all consumers, even to remotest customers at all times. See Figure 3. Thus customers a and b can draw power from generating station 1, 2 or 3.
Bulk of the power is generated by Country Electricity Boards. It can be thermal power using coal as fuel; team is generated in boilers and drives turbines which in turn drive alternators or generators. Power is also generated in hydroelectric power stations by using water power. A balanced proportioning of generation between thermal and hydro power ensures availability of power in all circumstances in all seasons of the year.
Hydro power is obtained from water, which in turn depends on seasonal rain fall. When rainfall is scanty, quantity of water collected is affected and power generation is reduced. Hydro power generation is thus close to the source or storage of water.
Thermal power stations based on generating steam in boilers by burning coal depend on regular supply of coal. This coal can come from near or from far. Its supply may be affected by strikes in collieries or by bottlenecks in transport system, and sometimes also by fluctuations in the quality of coal supplied.
Generally, cement plants should install its own Power Plant to meet at least 40% of their requirements. A large number of captive power plants installed by cement industry have been d.g. sets; many large cement plants have however opted for coal based thermal power plants.
In a cement plant also there is a mini grid receiving power from main electricity grid and also from plants captive power plant. They have to work simultaneously and hence should be synchronized when working in parallel, i.e., the voltage, frequency and phase must match.
In the last 25 years, variable speed drives (VSD) have been used more frequently in the cement industry. The main reason was to save energy in the production process. Generally speaking, variable speed motors would be used for electric motors listed in Table 1 below.
Thus some sections will have only LV supply and others both MV and LV supply and also DC drives. One option is to step down voltage from grid voltage for the total plant in one place and lead HT lines from it to respective sections in which MV motors are used. See Figure 4.
Both arrangements have their own positive and negative points. Main objective should be to achieve continuity of supply of power of right quality (fluctuations in voltage and frequency and phase should be within permissible limits) and flexibility (supply can be either from grid or captive power) without interruption.
Even when parallel busbar system or ring system is not used, the grid supply and captive supply must synchronize and work in parallel or individually without disrupting power supply to any section of the plant.
Power factor as close to unity between 0.95 to 0.90 lagging is desirable to get maximum from power purchased from the grid station. Lower the power factor, less is the useful energy available and greater the losses.
Say total load of above motors is 200 KW; total current at unity power factor would be 278 amps. If power factor were 0.85, the current would be 328 amps. All cables would draw correspondingly higher current right up to the substation.
Overall power factor can be improved to ~ 0.96 lagging. Current will reduce by 17 %. See Figure 7. Total power factor for the plant can be worked out in this fashion. If synchronous induction motors are not available, capacitor banks of suitable ratings and voltage are added in the circuit to obtain desired improved PF.
One of the first things to be done in designing the distribution system is to work out the power to be drawn from the grid for the plant. This can be drawn on a broad basis starting from overall power consumption of similar cement plants.
For example if similar plants are consuming 95-100 kWh/ton of cement, it may be assumed that the new plant will also consume the same amount and total power to be drawn calculated as shown in subsequent paragraphs.
Alternately the exercise may be done step by step. For this the first step is to arrive at departmental power consumption of each section in terms of power/ton of material handled. Then convert it into clinker and then into power per ton of cement.
For conversion power factor and load factors are to be taken into account. Power factor has been dealt with above. Though it would be maintained at 0.95, for working out power to be procured, it may be taken as 0.9. Load factor is a usage factor; all machines do not run for all the 24 hours and at a constant load.
For cement plants where most sections work in three shifts, it is customary to take load factor as 80%. Thus if 15260 KW are required and load factor is 80%, rating to be installed would be 15260/0.8 = 19080 KW. Power required to be obtained in KVA at 0.9 PF = 21200 KVA.
The substation capacity should allow for some margin for additions etc., that are not foreseen today. Therefore for the first phase, electrical demand would be fixed at with say a 25% margin. That would be 21000 1.25 = 26500 KVA say 26.5 MVA.
In selecting transformers, it is a good idea to select two transformers in parallel rather than one. Transformers are generally loaded up to 70 to 80 % of their rating. In above case total load = 26.5 MVA. Total rating of transformer would be 26.5/0.7 = 38 MVA. It would be preferable to select two transformers of 19 MVA each or even 20 MVA each.
Many a time sudden overloads or simultaneous working of all sections can push up the maximum demand and power drawn will exceed contracted maximum demand. In such a case, fine is to be paid. In times of power cuts, contracted demand would not be utilized.
Excellent presentation starting with the basics, the flowchart of how cement is made, then on to the electrical technologies and applications. Perfect for Cement Processing for Dummies and for the cement savvy electrical engineers.
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China manufacturing industries are full of strong and consistent exporters. We are here to bring together China factories that supply manufacturing systems and machinery that are used by processing industries including but not limited to: ball mill, grinding machine, milling machine. Here we are going to show you some of the process equipments for sale that featured by our reliable suppliers and manufacturers, such as Cement Mill. We will do everything we can just to keep every buyer updated with this highly competitive industry & factory and its latest trends. Whether you are for group or individual sourcing, we will provide you with the latest technology and the comprehensive data of Chinese suppliers like Cement Mill factory list to enhance your sourcing performance in the business line of manufacturing & processing machinery.
The particular challenge was maintaining the total length of the new slip ring motor with millimeter precision. In this case, the motor has two shaft ends and it had to be prepared for immediate commissioning without any changes of the on-site foundation. And all had to be done within just one week of time.
With international deliveries, as in the case, it is essential for us to prepare the motor for immediate commissioning. says Mathis Menzel, CEO of MENZEL Elektromotoren. Therefore, we take a very close look at all customer documents and inquire about the motors purpose. We often find out that small changes would result in a more efficient and more reliable solution for a specific application. Detailed enquiries are our trademark we do not simply deliver what the customer asks for, but what they really need.
We took a new 1900 HP slip ring motor from our Berlin warehouse. After performing a number of extensive technical modifications to ensure complete mechanical and electrical compatibility the motor was ready for delivery in just a one week.
Such a quick response time is possible because of our comprehensive stock a key part of MENZEL's strategy that allows for the modification and customization of standard motors to match customer needs in short order.
Our technicians modified both shaft ends in diameter and length to be matched to the original motor. And, since the motor from stock had a lower shaft height than the original motor at the cement mill, we also manufactured and supplied specific adapter plates by which the anchors are adjusted. These customized adapter plates were made in our in-house welding shop, which allows flexible production of special components and custom-made welded designs at all times.
In this case the US end-customer was faced with a potentially very costly downtime of their cement plant, when the original motor for their mill broke down unexpectedly. With standstill costs rising by the minute, and no spare drive available at the site, a new replacement motor was urgently needed.
Usually, motors of this size and configuration are project specific long lead items, not available from main-stream OEMs so quickly. It can often take several months for a motor of this size and complexity, to be manufactured or repaired.
In order to guarantee quick delivery to the customer in any eventuality, we maintain an extensive inventory of three-phase asynchronous motors with either squirrel cage or wound rotor designs, as well as a large range of DC motors.
Our company has been supplying various industries for more than 90 years and is capable of providing suitable drive solutions for virtually any large-scale motor application. In the cement industry, this mainly applies to process-relevant motors in mills and crushers, compressors, fans and rotary kilns.
With regard to customized solutions, we offer more versatility than many large players in the market, says Guido Wolf, Head of High Voltage Drives at MENZEL. Thanks to decades of experience and close cooperation with users from the cement industry and similar key industries, we can quickly and reliably identify cost-efficient solutions
Through our many years of experience in the manufacturing of cement mill motors, we are familiar with a wide variety of requirements and can advise customers from the industrial cement sector around the world. MENZEL electric motors are being operated in numerous industrial plants, not only cement plants.
China manufacturing industries are full of strong and consistent exporters. We are here to bring together China factories that supply manufacturing systems and machinery that are used by processing industries including but not limited to: ball mill, grinding machine, grinding mill. Here we are going to show you some of the process equipments for sale that featured by our reliable suppliers and manufacturers, such as Ball Mill For Cement. We will do everything we can just to keep every buyer updated with this highly competitive industry & factory and its latest trends. Whether you are for group or individual sourcing, we will provide you with the latest technology and the comprehensive data of Chinese suppliers like Ball Mill For Cement factory list to enhance your sourcing performance in the business line of manufacturing & processing machinery.
Cement is manufactured by heating a mixture of ground limestone and other minerals containing silica, alumina, and iron up to around 1450 C in a rotary kiln. At this temperature, the oxides of these minerals chemically transform into calcium silicate, calcium aluminate, and calcium aluminoferrite crystals. This intermediate product forms nodules, called clinker, which is then cooled and finely ground with gypsum (added for set-time control), limestone, supplementary cementitious materials, and specialised grinding aids which improve mill energy consumption and performance to produce cement.
The finish mill system in cement manufacturing is the second to last major stage in the process, where the feed material is reduced in size from as large as several centimeters in diameter, down to less than 100 microns (typically less than 10% retained on 45 microns). This is accomplished by grinding with the use of either ball mills or vertical roller mills, sometimes in combination with a roll press.
This operation typically consumes somewhere between 30 to 50 kWh per tonne of cement produced, and is the single largest point of consumption of electrical power in the process. Although concrete is the most sustainable building material available , with over 4 billion tonnes of cement produced and consumed world-wide, optimisation of the grinding process can provide significant reductions in energy consumption and environmental impacts.
As concrete became the preferred building material, it became readily apparent that in order to meet the increasing demand, improvements in grinding technologies and operational efficiencies were required.
Early hydraulic cements were relatively soft and readily ground by the technology of the day using millstones. The emergence of portland cements in the late 1840's presented a challenge however, due to the hardness of the clinker, resulting in a coarse cement product (with up to over 20% over 100 microns). This resulting cement was slow to hydrate and prone to issues with expansion due to large free-lime crystals. It wasnt until improved quality of steels were developed and the introduction of the ball mill in the late 19th century that grinding technology improved, allowing for a four-fold increase in compressive strengths during the 20th century  where finer grinding was needed to improve concrete performance and meet construction schedule demands.
Although ball mills were first introduced in the 1860s, the main progress was made during the 1870s to 1900s in Germany, where its growing cement and chemical industries increased the demand for finer grinding . The first tumbling mill to gain reasonable acceptance was designed by the Sachsenberg brothers and Bruckner and built by Gruson's Workshop in 1885, which was subsequently acquired by the Krupp Company.
The mill consisted of a drum lined with stepped steel plate with 60-100 mm steel balls. Fines were discharged from the mill through apertures in the plates, with coarse material in the discharge screened and reintroduced through slits between the plates.
The initial product on the early mills was particularly coarse, due to large aperture sizes necessary to prevent blockages, which led to a modification to discharge product through an end trunnion in the early 1900s to improve performance up to a couple tonnes per hour. Around this same time, F.L. Smidth and Co. was rapidly growing through contracts to build cement plants and acquired the rights to a tube mill from a French inventor, selling it worldwide after redesigning it.
A modern ball mill is a horizontal cylinder thats partially filled with high-chrome martensitic steel balls that rotates on its axis imparting a tumbling and cascading action to the balls. Material is fed through the mill inlet and initially crushed by impact forces and then ground finer by attrition (chipping and abrasion) forces between the balls.
An early approach to grinding was the use of a short tumbling mill to break the large clinker down to the size of grit and then a long tube mill to grind the grit down to powder. The next development involved the combination of those two stages into one piece of equipment, known as the multi-compartment mill, in Germany.
Modern ball mills are usually divided into two chambers, separated by an intermediate diaphragm, allowing the use of different sized grinding media to focus the crushing action in the first chamber, and attrition in the second. The ball mill shell is protected by carefully designed wear-resistant liners which promote lifting action to the ball charge in the first chamber, and cascading action in the second. Liners in the second chamber are sometimes designed to classify the balls so that the larger balls tend toward the central partition and smaller balls tend toward the outlet.
Balls diameters are typically 50-80 mm in the first chamber and 15-40 mm in the second chamber, where the ball charge design must be optimised based on the inlet material size, material hardness, and the desired size reduction. The ball charge typically occupies around 30%-36% of the volume of the mill, depending on the mill motor power and desired energy consumption and production rates. Air is pulled through the mill by an induction fan to control material throughput and temperature.
To solve the issue of large particulate in the discharge, the industry looked to closed-circuit operation with an air classifier to collect the fine particles as one product and recycle the larger particles back to the mill. As early as 1885, Mumford and Moodie secured a patent for an air separator being used in the flour industry.
This type of circuit started a trend which became common practice in the 1920s after Sturtevant developed an air classifier for the tobacco industry. Its adoption, which became commonplace by the 1950's, led not only to improved cement performance, but increases to production and energy efficiency by as much as 25% due to reductions in over-grinding. Development of the separator has continued from the so-called first generation to the current third generation of high-efficiency separators.
The first generation separators are very similar to the Mumford-Moodie design with one motor driving a distribution plate, the main fan, and an auxiliary fan. The second generation incorporated an external fan and external cyclones but gained only marginal improvement in classification efficiency. The modern generation of high efficiency separators, led by the development of the O-Sepa by Onoda Cement Co. in Japan in the 1970s, has an external fan which draws significantly more air through a rotating cage, increasing the ratio of air to material and the size of the open area in the classification zone to greatly increase efficiency.
Around this same time in the late 1970's and early 1980's, Professor Schonert developed and patented the key requirements for size reduction of many particles by compression of the particle bed using high pressure grinding rolls, first licensed to Polysius. The incorporation of this as a pre-crushing stage to ball mills with high efficiency separators led to circuits that were even more efficient and versatile. The roller press consists of a pair of rollers set 0.25 to 1.25 apart rotating against each other, through which the feed is introduced and compressed at up to 300 MPa. The material emerges as a cake of highly fractured particles and can reduce energy consumption of a ball mill by 20 to 40%.
Another major development was in 1906 by Grueber with the initial stages of what would become the vertical roller mill for grinding coal in Germany. In 1927 the first Loesche mill was patented which featured a rotating grinding track that used centrifugal force to push the grinding stock outwards from the center of the mill under high pressure roller wheels and into the airstream of the internal air classifier. This mill was adapted in the late 1930s for grinding raw mix and cement. However, it wasnt until the 1960s where rapid development in optimisation and up-sizing led to its increasing popularity in cement production, and not until the early 2000s that it began to become popular for cement grinding, due to higher grinding capacities and around 25% lower power consumption compared to the ball mill.
One of the most significant developments for the cement industry dates back to 1931, when an attempt was made to mix carbon black in concrete to make a darker middle lane on U.S. Route 1, in Avon for passing. Initially, the carbon black did not disperse well and rose to the surface giving the concrete a mottled appearance. Dewey & Almy (acquired by W.R. Grace in 1954 and later leading to GCP Applied Technologies) developed and produced a product called TDA (Tuckers Dispersing Agent) which helped the dispersion of carbon black and led to better workability and strength.
TDA was then tried in cement finish mills where it was found to improve mill operability with higher throughput and better product fineness, strength, and flowability, due to the dry dispersion of cement powder. The initial commercial versions of TDA were based on modified lignosulphonates and this began the modern grinding aid industry as well as leading to the development of water reducing admixtures. By the early 1960s amine acetates and acetic acid were also being used in grinding aids, and then glycols in the late 1960s and early 1970s. The 1990's saw the introduction of performance enhancing grinding aids which are continuing development to optimise particular mill circuits and product performances.
One of the biggest challenges faced in the grinding industries was matching an appropriate mill and motor to the required feed rate, product size, and material grindability. This led to Allis-Chalmers Company establishing a research laboratory in 1930 where Fred Bond further developed the theory of comminution by introducing Bonds Work Index in 1952 (to be continued)
The vertical roller mill (VRM) is a type of grinding machine for raw material processing and cement grinding in the cement manufacturing process. In recent years, the VRM cement mill has been equipped in more and more cement plants around the world because of its features like high energy efficiency, low pollutant generation, small floor area, etc.
The VRM cement mill has a more complex structure than other types of cement mills, so we need to ensure the following aspects are normal during the operation, or the machine may not be able to function well.
Too thick material layer will reduce the grinding efficiency of the vertical roller mill. When the pressure difference of the mill reaches the limit, the material layer will collapse and affect the operation of the main motor and the discharge system.
There are many factors that may make mill body vibrate, including the grinding pressure, material layer thickness, air volume and temperature, accumulator pressure, wear condition of the roller and the grinding plate, etc.
The grinding pressure of the mill should be adjusted according to the fed quantity, the particle size, and the grindability of the material. It must be well controlled to maintain the thickness of the material layer, reduce the vibration of the mill body, and ensure that the stable operation of the mill.
Increasing the grinding pressure will improve the grinding capacity of the mill, but the grinding capacity will stop increasing when the grinding pressure reaches a certain critical point. If the set pressure of the hydraulic cylinder is too high, it will only increase the driving force and accelerate the wear of parts, but not improve the grinding capacity.
On the other hand, too high grinding pressure will cause the thickness of the material layer to decrease, which further leads to the increase of the vibrating speed of the mill and accelerates the wear speed of the parts.
The gas temperature at the discharging port can be increased by increasing the opening of the hot air door and reducing the opening of the circulating air door. However, when the gas temperature exceeds 130 , the equipment will also be damaged. For example, the dividing wheel at the lower part of the cyclone will expand and get stuck, and the lubricating grease of the grinding roller will dry and crack, which is also unfavorable to the tail dust collection bag.
In vertical roller mills, the air volume in the mill is determined by the material feed rate. The air volume can be controlled by adjusting the power of the circulating fan of the mill or the opening of the exhaust fan at the kiln tail.
If the air volume is too large, the pressure difference in the mill and the current of the main motor will decrease, the thickness of the material layer will become thin, and the vibration degree of the mill body will become strong.
If the air volume of the system is too small, the thickness of the material layer, the pressure difference in the mill, and the current of the main motor will increase, and so will the vibration speed of the mill.
When operating the vertical roller mill, the operator must control the inlet and outlet air valves to make the air volume of the system in a balanced state, so as not to affect the air pressure at the back end of the rotary kiln.
Vertical raw mill is one kind of raw mill, generally used to grind bulk, granular, and powder raw materials into required cement raw meal in the cement manufacturing plant. Vertical raw mill is an ideal grinding mill that crushing, drying, grinding, grading transfer set in one. It can be widely used in cement, electric power, metallurgy, chemical industry, non-metallic ore, and other industries.
Foundation support: The foundation seat of the vertical raw mill is a set of steel welding parts, which is buried in concrete. The driving device of the vertical raw mill and the fixed seat of the tensioning hydraulic cylinder are installed on the foundation support.
Grinding table liner: The wear-resisting liner is fastened on the grinding table and the grinding roller rotates on the wear-resisting lining plate. The raw material is ground between the grinding table and the grinding roller.
Grinding roller: There are four grinding rollers, which are distributed on the grinding table. The diameter of the grinding roller is 2240m. When the grinding table liner and roller skin reach a certain limit of wear, it shall be replaced.
Hydraulic tension system: the hydraulic cylinder produces the pressure needed for the grinding roller to tighten, and the tension rod transmits the tension force of the hydraulic cylinder. The hydraulic cylinder is equipped with a nitrogen airbag to absorb the vibration of the raw mill during operation.
Auxiliary drive: The main engine drive is equipped with an auxiliary drive device, which can make the vertical raw mill start smoothly. The auxiliary drive is also used for the accurate position required in the inspection of the grinding table and the maintenance of the grinding roller.
Grinding: The raw material enters into the grinding through the sliding tube. Under the action of centrifugal force, it moves circumferential around the center of the grinding disc and radially outward along the grinding disc to enter the grinding area. There is a retaining ring around the mill, and the material forms a material bed on the vertical raw mill.
Selecting: except part of the fine powder is discharged with the airflow, and the rest of the material overflows from the retainer ring and is fed into the dynamic cement separator by the external circulation bucket elevator. The fineness of the finished product is R0.09 < 12%, and the coarse material is re-put into the vertical raw mill.
Drying: The heat source of drying materials comes from the 300 hot flue gas in the preheater at end of the cement rotary kiln, which is divided into two ways and sent to the vertical raw mill and the stepped cement separator respectively, and then into the dynamic cement separator and electric dust collection.
Cement mills are the milling machines used in cement plants to grind hard clinker into fine cement powders. Cement ball mill and vertical roller mill are two most widely used cement mills in todays cement grinding plants and are also the main types of cement mill we produce.
As a professional cement equipment manufacturer, AGICO has rich experience in the designing and manufacturing of cement ball mills and vertical roller mills. Our cement mills have extraordinary performance in the cement grinding process of the new dry process cement plants.
The cement ball mill is mainly composed of a horizontal cylindrical shell, feeding & discharging hollow shafts, liner plates, and grinding media. The mill body is a long cylinder, with many grinding balls inside. The cylinder is made of steel plate, and the inner part of the cylinder is fixed with steel lining plate; the grinding balls are steel balls with different diameters, which are installed into the cylinder in a certain proportion. There are also ball mills that use steel segments instead of steel balls as grinding media.
There are two chambers in the cement ball mill. When the ball mill is operating, the clinker is fed into the first chamber in the cylinder body through the hollow shaft at the feeding end of the mill. When the cylinder rotates, the grinding balls, under the action of inertia, centrifugal force, and friction force, clings to the lining plate inside the cylinder and rotates with it. When they are brought to a certain height by the lining plate, they will be thrown down due to gravity, and the clinker in the cylinder will be smashed.
After coarse grinding in the first chamber, the clinker enters the second chamber through the single-layer partition board. The second chamber is inlaid with a flat-lining plate and steel balls, which further grind the material into cement powders. The powders are finally discharged through the discharge grate plate, and the cement grinding operation is completed.
Vertical roller mills (VRM) are a type of mainstream clinker grinding equipment in the cement manufacturing process. Vertical roller mills are still newish cement mills since their history in cement production is no more than 20 years, but they have already become the standard cement equipment in many regions and are getting more and more popular among cement producers.
When the vertical mill works, the motor drives the grinding disc to rotate, and the grinding roller rotates around the grinding roller shaft driven by the disc. The material entering from the feeding port falls in the center of the grinding disc and moves towards its edge under the action of centrifugal force. When the material passes through the grinding track, it is meshed between the roller and the disc and crushed by them. After grinding, the material continues to move towards the edge of the disc until it overflows. An air duct ring is installed around the grinding disc, from which the hot air flows out at high speed from bottom to top, and carries the spilled materials. The material with large particles will fall back to the grinding disc, and the material with small particles will be brought into the powder concentrator for coarse and fine classification. The coarse powder falls back to the grinding disc for regrinding, and the fine powder meeting the requirements is sent out as the finished product, which is collected by the dust collector at the upper outlet along with the airflow.
Applications: It widely used in cement production, silicate products, new building materials, ferrous and nonferrous metal processing, electric power, ceramics and other industries of material grinding.
Raw mill is also called cement raw mill, similar tocement ball mill, it is an importantcement milling equipment used in the cement production process.Raw mill is mainly used for grinding cement raw meal in the cement factory production process. It is also suitable for metallurgical, chemical, electric power and other industrial mining enterprises to grind various ores and other grindable materials.
Cement raw meal is a mixture of various raw materials before cement calcination. It is a mixture of lime raw material (mainly composed of calcium carbonate), clay raw material (aluminosilicate containing alkali and alkali soil) and a small amount of calibration raw material in a certain proportion and ground to a certain fineness. In order to meet the success of the subsequent calcination process, the grinding of the raw meal must be uniform in fineness and ensure the chemical composition of the mixture is stable.
Raw mill in cement plant is very suitable for cement raw meal grinding because of its strong adaptability to raw materials and adjustable grinding fineness. It is the most commonly used grinding machine in the grinding stage of raw materials in the cement plant.
The cement raw mill is generally cylindrical in the horizontal direction, and gears are driven at both ends. After the motor is turned on, the cylinder is rotated. Raw materials are evenly fed into the first inner silo from the feed port at one end. The inner wall of the silo is provided with a step liner or a corrugated liner, and steel balls of different specifications are installed inside as the grinding media.
When the raw material grinding process starts, with the rotation of the cylinder body, the steel balls and materials are brought to a certain height and then fall down, so that the reciprocating cycle can produce impact and grind on the materials. Material is ground at the primary stage in the first inner silo to achieve rough grinding size. After that, the material passes through the single-layer partition board to enter the second inner silo for further grinding.
The inner wall of the second inner silo is a flat liner plate. The number of steel balls is more and the size is smaller than that of the first inner silo. The grinding of materials is more sufficient. In the raw mill grinding process, the grinding material is discharged from the grinder through the discharge hole, and the fineness of the qualified material is sorted by the sorting equipment, while the fineness of the unqualified material is sent back to the cement raw mill by the sorting machine. And unqualified material will be ground until the fineness meets the requirements.
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