It is a classic powder grinding equipment in the power industry and has a high market share. Raymond mill is grown in technology, stable in performance, energy-saving and efficient, durable, and powdered at a time. The fineness can be adjusted freely.
Raymond mill is mainly used in mining, metallurgy, chemical, building materials, petrochemical, coal, smelting, fertilizer, medicine, infrastructure, roads, engineering, abrasives, food, feed, plastics, and other industries. The hardness of grinding materials is 7 grade, the humidity is about 8%, it can grinds various raw materials.
Finished products can be adjusted in arbitrarily about 30-350 mesh. It is processable for cement clinker, quartz sand, feldspar, calcite, lime, limestone , dolomite, barite, graphite, gold and silver ore, rutile, titanium dioxide, kaolin, bentonite, aluminum ore, coke gemstone, fluorite, wollastonite, phosphate rock, rare earth, iron red, metal silicon, electrolysis , niobium alloy, silicon carbide, gold steel sand, smelting metal, calcium magnesium ore, coal, activated carbon, humic acid, carbon black, grass ash, coal gangue, slag, zircon sand, iron ore, iron fine powder, talc , granite, potash feldspar, marble, barite, wax feldspar, clay, glass, coke, petroleum coke, water slag, slag, fly ash, cement, pigment, clay, ceramsite sand, saline, muddy sand Milling materials such as additives, fire-fighting agents, curing agents, waste ceramics, waste bricks, refractory materials, aluminum ore, bauxite, etc.
Raymond Mill has been widely used in the processing of non-metallic minerals since its introduction to China for more than 20 years. However, with the extensive development of non-metallic minerals in the application of ultra-fine powders, downstream enterprises are increasingly demanding non-metallic mineral products, especially for product fineness, which makes traditional Raymond mills powerless. So Dalil Heavy Industry Technology Department has carried out in-depth analysis and research on traditional grinding machines, and solved many fatal defects such as frequent maintenance, high maintenance cost, and insufficient fineness of grinding, and developed a set. A new ultra-fine Raymond mill that is crushed, ground and ultra-fine.
Due to its high efficiency, low energy consumption, ultra-fine refinement, small floor space, low capital investment and no pollution in the environment, it is widely used in the grinding of mineral materials in metallurgy, building materials, chemical industry, mining and other fields. Non-flammable and explosive minerals with Mohs hardness less than seven grades and a humidity below 6% is suitable such as gypsum, talc, calcite, limestone, marble, potash feldspar, barite, dolomite, granite, kaolin, bentonite, medical stone, bauxite, iron oxide red, iron ore, etc.
The main machine rotates the central shaft through the double belt combined transmission mechanism. The upper end of the shaft is connected with the plum blossom frame, and the grinding roller and the plum blossom frame are assembled to form a dynamic grinding system, and a swing fulcrum is formed. When the plum blossom frame rotates, the grinding roller presses the peripheral grinding ring to form a complete crushing combination, and the grinding roller rotates around the grinding ring while being rotated by the friction force. With the rigorous blade system, located in front of the grinding roller, during the operation, the material is thrown up and fed into the grinding ring to form a pulverized material layer. The material layer is crushed by the extrusion and friction generated by the rotation of the grinding roller. In order to achieve the purpose of grinding.
Non-flammable and explosive ore with a Mohs hardness of 6 or less and a humidity below 6%, such as calcium carbonate, graphite, bentonite, wollastonite, coal powder, water slag, fly ash, alumina, zircon sand , quartz sand, gypsum, talc, calcite, limestone, marble, barite, dolomite, granite, kaolin, bauxite, iron oxide red, iron ore, power plant environmental protection (desulfurization denitration).
Silicate cement clinker, a main kind of material for portland cement, consists of the chemical components mainly including four kinds of oxides of CaO\SiO2\Fe2O3\Al2O3, which accounts for 95% of silicate cement clinker, the other 5% are found to be another oxides such as MgO\SO3.
Original cement clinker needs grinding to get meshes of them before getting calcined and this procedure requests a grinding machine. In order to save your investment, I am hereby to recommend raymond mill for you.
As a popular kind of grinder, raymond mill is designed to process at least 200 kinds of minerals such as cement clinker, stone flour, barite, bentonite, calcium carbonate, clinker, coal, dolomite, lead xide, limestone, marble, quartz, ultrafine to name but a few.
I have done some research through Google and find that a raymond mill could be sold for 3,000-12,000 dollars. If you prefer a more competitive price of raymond mill, welcome to contact us, and we would like to offer you a customized solution and a better price.
This post begins with a look at the characteristics that make cement manufacturing so tough on material handling equipment. Following that is an examination of nine typical applications in a cement plant where rotary valves and feeders are proven problem-solvers.
Long-Cycle Operation Cement manufacturing is nearly a year-round, 24 hours per day business. Planned downtime is minimized. Unplanned downtime is not just inconvenient it is costly. The expectation is that equipment will run reliably from one outage to the next.
Materials Many of the precursors and inputs into the cement manufacturing process are inherently abrasive, including limestone, silica, slag, ash, and others. The critical intermediate cement form, clinker, is one of the most abrasive products in any process industry.
Volume The production scale required for economic, financially-viable cement manufacturing is enormous, and plants have gotten continuously larger over the years. Plants with a cement production capacity of 3 to 4 million tons per year are relatively common and far from the largest.
Particle/Piece Size At the front end of the process, quarried raw materials can arrive at the cement plant in a size equivalent to a softball. To continue the comparison, raw coal and clinker are usually in the tennis ball size category. Achieving the fine, powdered condition that is associated with cement is a continuous size reduction journey.
In North America, the majority of cement manufacturing plants use a vertical roller mill and an integrated separator (VRM) for grinding quarried limestone and other materials into raw meal. Throughput is usually in the range of 150-750 tons per hour. In raw mill feeding, a system of weigh-belts that discharge into the mill feeding device controls the material rate into the mill.
VRMs are fed either with a rotary feeder or a flap-gate system. In either, the primary role is to provide an airlock function to minimize the introduction of false air into the mill and separator.
A crucial consideration for cement plants is raw mill uptime. Rotary feeders, particularly new-generation designs such as the Precision PMCA Rotary Feeder, have proven to be much more reliable than flap-gates or older rotary feeders.
A Precision customer recently shared some illuminating statistics. Over a two-year operating cycle, accomplished without rebuilding the feeder, unplanned downtime was limited to less than 34 hours during planned production of 13,350 hours. 99.75% uptime!
A second significant advantage of rotary feeders over flap-gates is a much lower frequency and intensity of maintenance. The new generation of raw mill rotary feeders is made from heavier, thicker steel with a were building a tank attitude. Periodic maintenance is limited to an occasional visual inspection, bi-weekly or monthly lubrication, and little else.
VRMs are somewhat less common in finish mill applications. There are still many ball mills in use for cement grinding in North American. Functionally, the job of a finish mill feeder is the same as a raw mill feeder minimize false air passage into the mill: the airlock function. Finish mill feeders must handle large throughputs, 100-500 tons per hour rates are common.
For both rotary feeders and flap-gates, minimizing and controlling airflow into the mill despite the prolonged exposure to the sand-blasting effect is critical to performance. Improved rotary feeder designs, like the PMCA Rotary Feeder, and the use of abrasion-resistant steel can minimize gaps that allow false air infiltration.
Coal remains a common fuel choice for firing cement kilns in North America. Most plants receive their raw coal in a form that requires on-site grinding, using VRMs along with other mill types. Raymond bowl mills are particularly common.
Like the raw mill and finish mill applications, the infeed devices role here is as an airlock. A weigh belt system controls the feed rate. In most cases, coal mill feeders are smaller than raw mill or finish mill feeders with capacities of 10-100 tons per hour.
The #1 issue for coal mill operators is stickiness or coal build-up on all the material handling equipment, including the mill feeder. Raw coal, which is usually 3-4 inches or smaller, can have inherent moisture in it. If the plant receives its coal in open-top trucks or rail cars, surface moisture can accumulate. Surface moisture becomes even more problematic if the raw coal is stored outdoors.
Both conventional rotary feeders and especially flap-gates, struggle with handling raw coal. Maintenance and operations team members often spend hours trying to remove build-up to keep the system feeding and to maintain rate.
Cement plants have been substituting alternative fuels in place of coal for years. Liquid fuels and natural gas are outside the scope of this post. Solid fuels wood, tire shreds/chunks, carpet, plastics, nutshells, etc. are important fuel sources for cement plants, either year-round or in-season.
Rotary feeders in gravity-fed fuel systems segregate the negative pressure in the calciner from the atmospheric pressure outside to maintain balance in the calciner. The negative pressure is usually relatively modest. However, the potential for the system to go positive and push high-temperature gas back up into the rotary feeder means that the rotor-to-barrel clearance inside the rotary feeder must allow for a thermal shock. This increased clearance acts in opposition to what would otherwise be a tight clearance, low-leakage feeder.
Alternative fuels have a diverse range of caloric contents, bulk densities, and sizes. Plant control systems can compensate for variations in the first two. Variations in material size usually require a knife-style rotary feeder, like the Precision PMR Rotary Feeder, to minimize feeding disruptions.
Knife-style rotary feeders shear off oversized solid fuel pieces that would otherwise jam-up a rotary feeder and interrupt fuel flow. This ability means that the plant can utilize minimally-prepared fuels that are less costly than other heavily pre-processed fuels.
The alternative fuels section of this post discussed one pneumatic conveying application, and there are numerous others. For most pneumatic conveying applications, the rotary valve or rotary feeder will function as an airlock, but some applications may demand both airlock and metering functionality.
Properly designed pneumatic conveying systems are balanced and require the consistent introduction of the material into the air stream. A rotary valve or feeder with excessive internal clearance, either when new or after use, will reduce transport efficiency. Excessive internal clearance leads to blow-by, where the conveying air passes through the valve or feeder and out of the conveying line.
Loss of efficiency will cause the blower to consume more power and material transport rates to fall below target. The conveying air that passes through a wide-clearance valve or feeder also can disrupt the material being fed. This disruption can manifest itself as a fluctuating feed rate material, particularly something light, may not drop into the valve or feeder at the designed or assumed rate. A further issue is the possibility of dusting when the leakage through the valve or feeder is so great that material is blown out of the top of the vessel.
Proper sizing and matching of the valve or feeder and the pneumatic line injector (a T-injector in Precisions parlance) is critical to proper feeding in a pneumatic conveying application. A very common concern is the operating pressure of the pneumatic system higher pressure will wear out all the conveying system components, including a valve or feeder, more quickly than a low-pressure system.
Excessive or increasing blow-by is the issue in pneumatic system feeding devices. A well-built rotary valve or feeder is preferred over a flap-gate in the cement industry. Tight initial clearance and resistance to clearance-widening wear in a rotary valve assure a lower level of blow-by than a flap-gate.
Common in storage silos or silo farms that hold raw meal, additives, finished cement, or a pulverized fuel, rotary valves in silo discharge applications are usually a metering device. The valve may also serve as an airlock function when a silo is discharging into a pneumatic line or air-slide. As the silo location may be in a less-traveled area, durability and reliability in the rotary valve are essential it may take time for personnel to notice if a valve isnt working or is leaking.
Silo discharge applications often require large capacity rotary valves. Units sized for 5 to 8 CFR (cubic feet per revolution) are reasonably common, which would produce a transfer rate of more than 7000 cubic feet per hour. Depending on the bulk density of the material in the silo, this could equate to 250 to 300 tons per hour. Very high throughput silo discharge applications dictate a robust, long-lived rotary valve.
Rotary valves, such as the Precision PMV Modular Rotary Valve, outperform flap-gates in this application, can be quickly activated and, with an inverter-duty motor, ramped up or down to meet required transfer rates.
The most common method of dosing pulverized coal or pet coke to the kiln main burner is to use a Pfister DRW rotor weighfeeder. A rotary feeder is often installed above the DRW to meter fuel, allowing the Pfister unit to be neither starved nor flooded. For accurate weighfeeding, the DRW must have a full-head of fuel available to it at all times.
The Precision PMV and other rotary valves in this application have to work without fail and operate over long operating cycles. Failure of the rotary valve would take down the DRW and the kiln. Durability is the key in this application, making rotary valves with upgraded materials of construction highly recommended. The successful operation also calls for an inverter-duty motor in the drive package the same signal relayed to the DRW for more or less fuel controls the rotor speed of the valve.
DSI (Dry Sorbent Injection) systems, which are sometimes known as FGD (Flue Gas Desulphurization) systems, are a specialized subset of pneumatic conveying. These systems treat flue gas to remove SOx and other contaminants. The most common sorbent is hydrated lime, but other sorbents, including trona, activated carbon, or some types of ash, are used.
This is another application where the rotary valve has to be available to run at all times. The treatment of flue gas is so vital that DSI systems are often set-up as a so-called dual train system with duplicate blowers, rotary valves, and metering devices. These pull from the same sorbent silo and discharge into the same pneumatic line that feeds the lances in the flue.
As with other pneumatic conveying systems, excessive blow-by can be the major challenge in DSI systems. Flue gas treatment systems rely on a precise ratio of sorbent to gas. If some of the sorbent is not reaching the lances or nozzles in the flue, the system wont function properly. Hydrated lime presents unique problems due to its tendency to react chemically if over-heated and its tendency to build-up on metal surfaces if not kept very dry.
Tight-clearance rotary valves, such as the Precision PMV Modular Rotary Valve, are very desirable for DSI applications and are often equipped with optional upgrades to combat the issues with sorbents. These options include air purges, beveled rotor vanes, and zero speed sensors. Rotary valves for this application are generally small with capacities under 0.35 CFR (cubic feet per revolution.)
In many industries, rotary valves in dust collection systems can run for years and years with little attention as the products are mildly-abrasive, the loading is generally light, and there is minimal pressure drop. To some extent, these characteristics are similar in the cement industry except that products can be abrasive, particularly CKD (kiln dust), and at times at an elevated temperature.
While this application may be somewhat less demanding than others in a cement plant, it can be quite problematic if the rotary valves in a dust collector arent working. Housekeeping and clean-up can consume maintenance or operations man-hours if the valves arent working correctly or appropriately sized.
Rotary valves in dust collection systems are airlocks as they are discharging to atmospheric pressure usually to a screw conveyor or belt conveyor. The valves typically are relatively small with capacities generally less than 0.65 CFR; roughly a 12 valve.
There are numerous applications for rotary feeders and valves in cement manufacturing. The raw material and inputs, the existing process equipment, and the finished products at each plant vary considerably. So, it is difficult to apply hard-and-fast rules to selecting the best rotary valve or feeder for your application. However, here are some broad guidelines.
This is primarily a philosophical choice about costs. Smaller equipment running at a higher rate of speed usually requires a lower initial investment. However, the high speed will cause faster wear than a larger piece of equipment running more slowly. As a result, rebuilding or replacement costs will be incurred on a shorter cycle and measured over a medium-term horizon, overall equipment investment will be higher. Higher maintenance costs, for bearings, seals, and other components, also tend to correlate to operating speed further accentuating the expenses associated with the Small & Fast choice.
At Precision, our experience leads us to believe that valves and feeders will last longer and provide an improved total-cost-of-ownership if operated at 20 rpm or less and sized accordingly. We also have confidence that slower speeds and larger equipment will improve feeding performance. At higher speeds and with small diameter rotors, consistently filling the rotor pockets is difficult in Small & Fast.
Other valve and feeder manufacturers and some system design firms dont subscribe to the Large & Slow philosophy as the better choice. Our companys Mission Statement states, We provide solutions that deliver an exceptional return-on-investment and we are convinced that Large & Slow is a key to stronger ROI.
The hardest-to-know parameter in rotary valve or feeder sizing is pocket fill. For example, a dry, flowable material, coming out of a well-designed silo, with a consistently full-head of material in the silo, and into a valve with a sufficiently large inlet should fill the rotor pockets to at least 90%. Lots of qualifiers in that description, no?
Understanding all the details of the application is vitally important. Material moisture content can influence the fill assumption as can the tendency of the material to bridge. Particle size, specifically maximum dimensions, will have a significant impact.
Relatively small differences in pocket fill assumption can have an outsized impact on valve and feeder sizing. For example, in alternative fuels, changing the pocket fill assumption from 50% to 30% will push the feeder up at least one size larger or possibly two sizes. This change will impact equipment cost, the horsepower requirement, and the installation envelope.
Sizing for airlock-only applications is somewhat easier than for a combined airlock and metering device situation. In airlock-only apps, the sizing math is concerned with only the maximum anticipated throughput. Metering applications must consider minimum, maximum, and typical throughput rates and the turn-down that is achievable with the drive package.
In the cement industry, it is relatively common to run sizing calculations using the assumption of 30% pocket fill. This assumption provides for lots of growth in throughput in the future and provides reasonable assurance that the valve or feeder wont become a bottleneck.
One final subtlety regarding pocket fill assumptions in cement bears mentioning. Capacities are often provided to Precision in terms like 250 tons per hour. This sort of hourly rate is critical to proper sizing, but it does not describe the mini-surges or pulses that can develop in operation. Plant control systems frequently maintain feed rates within tight upper and lower bounds, but the potential for very short-term surges in rates are a reason not to assume a high-percentage pocket fill.
For many cement applications, particularly those where the sole function of the valve or feeder is as an airlock, the temptation is to assume that the tighter the internal clearances, the better. Up to a point, that is useful guidance.
Tighter clearances do reduce blow-by. For example, a Precision PMV-12 with a rotor-to-barrel clearance of 0.005 has 44% less blow-by than an identical valve with 0.010 rotor-to-barrel clearance, reducing blow-by from 108 CFM to 61 CFM.
Tight internal clearance (rotor-to-barrel) in rotary valves and feeders will reduce the pathways for blow-by or false air to migrate. Minimizing airflow is, by definition, the valve or feeders job as an airlock and will result in improved material handling and transport.
Rotary valves and feeders, once purchased and installed, become the responsibility of the plant maintenance team. Most cement industry insiders would agree that maintenance is the most overloaded department. Troublesome, maintenance-intensive equipment is something that they could happily do without.
Chief among these design features are such things as replaceable rotor tips, adjustable rotor tips, and feeder inlet flaps. Each has a certain theoretical appeal and can have a beneficial impact on performance when new.However, the downsides of frequent maintenance attention and the difficulty of even accessing these components to adjust them or change them out seem to us to strongly outweigh any benefits.
Heavy steel body panel inserts, bulletproof glass, and other Up-Armoring features increase occupant protection in limousines used by presidents, prime ministers, and other dignitaries. The same concept protects rotary valves and rotary feeders against abrasive wear.
Up-Armoring has its place in material handling equipment. However, too often, the Up-Armoring lacks a coordinated, thoughtful design. For example, Stellite-tipped rotors sound like a robust, durable feature. However, if that Stellite-tipped rotor is running inside an ordinary cast-iron valve housing, the gain in durability will be illusory or non-existent.
Up-Armoring should be one part of a product plan that includes excellent manufacturing workmanship, proper sizing, consideration of system design, and site-specific factors. Otherwise, it is just slapping expensive materials onto a valve or feeder for marketing purposes.
The kilns, the mills, and the control systems receive much attention in cement manufacturing. Rightfully so, as they are the keys to producing a saleable product. Weve described some of the considerations and complications in several feeding applications that, if not done correctly, have the potential to bring cement manufacturing to a halt, significantly disrupt production, or needlessly consume energy, fuel, and manpower.
Precisions strongly-held position is that rotary valves and feeders cost-effectively address all of the applications discussed here. If youd like to learn more about our solutions, please contact us. Precision is focused on solving the toughest cement industrys material handling challenges. Wed be delighted to help you overcome the material handling challenges in your plant.
Raymond roller mill, also known as Raymond mill, is a commonly used grinding mill in industrial production, can be used for processing more than 280 kinds of materials. It has the characteristics of stable performance, simple structure, convenient operation, long service life and high output. About its origin, I believe many people are holding a curiosity.
In 1906, C. V. Grueber founded the Curt Von Grueber Machinery Factory in the southern suburbs of Berlin. During this period, he manufactured the first MAXECON mill by using the patent he obtained in the United States. This mill was successfully applied as a coal mill in the MOABIT power station in Berlin, with grinding capacity up to 5 tons per hour. After that, E.C. Loesche became a shareholder and headed the Curt Von Grueber Machinery Factory. He purchased the Raymond Centrifugal Ring-roller Mill patent from the United States to produce the first generation Raymond mill system.
However, due to the limitation of roll diameter and rotation speed, Raymond mill was only suitable for soft, low ash and good grindability materials, while Germanys coal was hard, high ash and required higher grinding force, so Raymond mill was not popularized in Germany at that time, but widely promoted and applied in the United States.
In 1925, after E. C. Loesche summarized the characteristics and structural disadvantages of the first generation Raymond roller mill, he developed a grinding mill with the opposite grinding principle of the first generation. We called it the modified Raymond roller mill. The ventilation of this type Raymond mill system has two ways: positive pressure blowing and negative pressure blowing. While, although its roll diameter increases slightly, the grinding force does not increase much.
After the second generation, the Raymond branch of the United States developed a new generation of Raymond mill on this basis. We called it VR Raymond roller mill. This type of grinding mill uses a cylindrical roller and a grinding disc with an angle of l 5 degree. During the inspection and maintenance of the grinding roller, the automatic rolling out device and protection device are provided to prevent the metal contact between the grinding roller and the grinding disc. Besides, the grinding roller can be lifted in advance before the mill starts running to reduce the starting torque of the motor.
According to the accumulation and analysis of the on-site operation data for more than 20 years, AGICO, a Chinese cement plant equipment manufacturer, has manufactured a new generation Raymond mill which has more mature technology and more stable operation. Our Raymond mill can fine grind more than 300 kinds of materials with Mohs hardness below 9.3 and humidity below 6% in many industries, such as mining, construction, chemical industry, chemical fertilizer, etc. The finished product granularity can reach 0.125-0.044 millimeters. According to different requirements, the maximum fineness is up to 0.013 millimeters.
With the advanced process, competitive price and attentive service, AGICOs Raymond mill are appreciated by customers from home and aboard. If you have any need for Raymond mill or other cement plant equipment, please feel free to contact us!
AGICO Group is an integrative enterprise group. It is a Chinese company that specialized in manufacturing and exporting cement plants and cement equipment, providing the turnkey project from project design, equipment installation and equipment commissioning to equipment maintenance.
Cement mill is the core equipment forgrinding material afterclinker production. Generally, the cement mill can be called cement grinding mill. Among production cost of cement manufacturing, grinding powder consumption takes 35%-40%. The cement grinding plant is a vital link to control cement quality. To some extent, grinding quality can make up the shortage of clinker quality. In another word, the cement grinding mill can increase the cement quality and guarantee the qualification rate of cement. In general, cement mill can both apply for dry cement production and wet cement production.
Commonly, there are three hot types of cement mill in the cement industry: cement ball mill, Raymond mill, and vertical cement mill. AGICO Cement can supply cement mill according to your requirements. We also provide the answer to the question: how to choose a cost-effective cement mill? If you have any need of cement mill, welcome to ask!Get in Touch with Mechanic