grinding table for vertical roller mill - xinxiang great wall machinery co., ltd - pdf catalogs | technical documentation | brochure
Grinding table for vertical millIntroduction Advantage Process Case Inquiry CHAENG is specialized in manufacturing spare parts for vertical roller mill. The grinding table is the key part of vertical mill, mainly composed of table body, lining plate, press block, retaining ring, scraper plate, air ring, and wind deflector, etc. Weight Material Application Customizable 1-132T Carbon steel, silicon manganese steel Vertical roller mill Yes, based on user's drawings GREAT-WALL STEEL CASTING W Chat Now 133 Leave Message CHAENG is glad to offer you the quality services, ffi E-mail: [email protected] 0 WhatsApp: 1. Optimize the casting technology of grinding table and adopt advanced water glass sand modeling process to overcome the shortcomings of the previous structure, so that the grinding table base bears stress evenly; Increase the nip angle between grinding table and grinding rollers to avoid the erosion of the non wearing surface of grinding table; 2. Advanced machining equipment to ensure high surface finish of grinding table; 3. Nondestructive inspection of the stress surface before leaving the factory can ensure that the internal and external quality of the grinding table conforms to the industry standards; 4. CHAENG has a large steel casting base in the northern area of Henan Province, so it can not only provide a single grinding table manufacture service, but also provide solutions of large steel casting product for you! Process Base on the requirements of customers, CHAENG selects appropriate wooden mold for modeling design, and uses CAE software to simulate the casting process. Strictly according to the process procedures to produce high-quality grinding table: Case After years of development, CHAENG grinding tables for vertical roller mill have been sold to many provinces and cities in China, and exported to Europe, the United States, Japan and other countries and regions. CHAENG grinding table was applied to the GRMK46.41 vertical cement mill of Henan Yuhui Yellow River Building Materials Co., Ltd. , currently running smoothly and highly praised by users. EAT-WALL STEEL CASTING The grinding table of a cement plant in Hebei needs to be replaced because of its long running and serious wear. After careful comparison, the company selected CHAENG to supply grinding table for their 600,000T/A vertical cement mill, ultimately CHAENG impressed the customer with high-quality products and perfect service, the customer said: We will also choose CHAENG in the future when we need the grinding table! 1. Cost-effective CHAENG has the advanced casting equipment, strictly follows the national lever-2 detection standards, and executes 360 all-round nondestructive testing system, to ensure the reliable quality and long service life of steel castings. CHAENG is hailed as "high cost-effective steel castings manufacturer". 2. Fast delivery CHAENG has strong technical teams, detailed production scheduling, wide range of raw materials purchase channels, and perfect logistics delivery system, making efforts to achieve as fast delivery period as required. 3. "Three-heart" service The 24h fast response and the customer services in all 365 days rest your heart when you make choice, ease your heart when you use the products, satisfy your heart when you enjoy the services.
a first survey of grinding with high-compression roller mills - sciencedirect
The special feature of high-compression roller mills (HC-roller mills) is that a bed of particles is compressed between two rollers to a high solid density more than 70% of volume. The size reduction occurs by interparticle crushing. The milling force must be adjusted to a level so that the particle bed is loaded by a compressive force per unit area exceeding at least 50 N/mm2 and in most practical cases being within the range between 100 and 300 N/mm2. The material leaves the mill as flakes, which have to be deagglomerated in a succeeding operation. Nevertheless, both operations consume much less energy thaan a ball mill. Furthermore HC-roller mills have less wear and reduce overgrinding.
industrial roller mill | roller mill manufacturer | williams crusher
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Williams Patent Crusher designs and manufactures high-quality industrial roller mills that consistently deliver a uniform grind for almost any material. It is our goal to provide a machine that offers a better value for our customers while still being a powerful piece of machinery.
One of the key components of the Williams vertical roller mills is the customization options that are available. Since our industrial roller mills are used for a wide range of applications and material size reduction, our machines allow for custom feeder selection to ensure a high-capacity, trouble-free operation no matter what kind of material you need reduced.
Our team sets itself apart with a diverse product line and customized systems for a variety of applications. The Williams roller mill is a perfect example of the kind of versatility our engineers infuse into all of our machines. Built to last and applicable to a variety of uses from limestone and clay to gypsum and coal is what makes the roller mills and all Williams designs stand out from the pack.
Centrifugal roller mills use the centrifugal force of cylindrical grinding rolls to crush material into a uniform particle size and grind, turning materials into small granules or fine powder. Some of its typical applications include the particle size reduction of coal, glass, gypsum, limestone, and more.
Williams roller mills can perform simultaneous grinding and drying functions with one continuous operation. The roller mills simultaneous grinding and drying features are typically for materials with higher moisture such as limestone and clay. Learn more about the Williams machines capable of simultaneous grinding and drying functions.
Roller mills are industrial mills that uses cylindrical rollers to crush and grind material instead of flat plates like other pulverizers. The Williams Roller Mills are designed to provide years of reliable, consistent, and efficient operation, but the reason why Williams is one of the leading roller mill manufacturers is their ease of use and maintenance.
1. Product Control:Micrometer control of finished product. Product size (regardless of turn down or grinding element wear) is controlled by utilizing the Williams High Efficiency Turbine Separator equipped with a variable speed drive. Drive adjustment is controlled automatically from centralized control panel.
2. Fluidized Bed Drying:Hot gas entering the grinding chamber below the grinding rolls fluidizes the entire grinding chamber. This promotes rapid efficient drying of all material types, including lignite and sorbent. Large open area through grinding chamber allows particle terminal velocities to be maintained while fluidized by heated gasses.
3. External Gear Box:External right angle gear box eliminates damage from heat and contamination of product into gear box. Removal of gear box from skid allows change out of main vertical shaft.
4. Turn Down Ratio:Nearly infiniteturn down while maintaining product size. Williams adjusts the mill grinding rate as a direct function of control system demand. The mill capacity is modulated by varying mill speed.
5. Mill Speed: Mill speed modulation varies the centrifugal force of the grinding rolls. Product capacity ranges from 100% to 0% utilizing an optional variable frequency A.C. drive.
6. Bottom Discharge: Auxiliary Mill Bottom Discharge permits production of a second granular product or beneficiation of the principal product by the removal of pyrites and tramp material, either can be done simultaneously with fine grinding and drying.
The Williams centrifugal roller mills were designed with efficiency in mind. Each part works in tandem to efficiently dry, grind, and classify material. Learn more about how industrial roller mills work when they are designed by the experts at Williams.
B. Base of the Roller Mill
C. Centrifugal Main Mill Fan
D. High Efficiency Turbine Separator
E. Cyclone Collector
F. Fabric Collector
H. Recycle Line
K. Discharge Spout
Operation of the Williams Roller Mill System is completely automatic.
The feeder (A) introduces raw material into the grinding chamber in the base of the Roller Mill (B)at a rate determined by pressure variations with the grinding mill. Plows located ahead of each roller direct the material upward and between the grinding rolls and the heavy alloy steel bull ring where it is ground to size. The grinding rolls are free to swing out centrifugally which forces them to bear upon and grind the raw material. Being free to pivot, the rolls automatically assume the proper position for grinding and need no adjustment to compensate for wear.
Once ground to size, material is swept out of the mill by the controlled air flow from the centrifugal main mill fan (C). Air suspended, the ground material passes through the adjustable Williams High Efficiency Turbine Separator (D). In the separator, an accurate size classification is made which allows product size material to be conveyed away from the grinding mill while oversize material is returned for additional grinding. Product sized material is removed from the airstream by the Cyclone Collector (E). Typically, a conveyor or product storage bin will be located to accept the product as it exits from the bottom of the Cyclone Collector.
Fabric Collector (F): Airborne fines which remain entrained in the exhaust gas from the Cyclone Collector are removed by a high efficiency fabric dust collector located downstream from the cyclone. The efficiency of the basic Roller Mill System becomes a highly efficient means of removing moisture from the raw material by the simple addition of an air heater (G) as shown in color.
Further refinements to the heater system allow the Williams Roller Mill to process hazardous dusts in a controlled low oxygen atmosphere. A recycle line (H) from the dust collector to the heater enables a further reduction in oxygen level. This is Williams' patented Inert Gas System.
Product beneficiation is possible in the Williams Roller Mill System by continuous removal of impurities through a discharge spout (K) located beneath the grinding mill.
The Williams team took great care when designing each component of our industrial roller mills. Learn how each part of the roller mill works to create consistent, uniform product with maximized efficiency from the primary and secondary fans to the air heater.
Williams industrial roller mills are used for a wide range of applications and materials, which means that the proper feeder selection is essential for high-capacity, trouble-free operation and more efficient production.
You can customize your vertical roller mill depending on what material you need reduced. Learn more about the different types of feeders that can be furnished to fit Williams roller mills. Or, contact the Williams team today to discuss your specific customization requirements for one of our roller mills.
effects of grinding corn through a 2-, 3-, or 4-high roller mill on pig performance and feed preference of 25- to 50-lb nursery pigs - engormix
In Exp. 1, 320 pigs (DNA 400 200, initially 23.6 lb) were randomly allotted to 1 of 4 dietary treatments with 16 pens per treatment and 5 pigs per pen for a 21-d growth trial. The 4 dietary treatments used the same corn-soybean meal-based formulation that was mixed from the same batch of ingredients. Corn was ground through the same 4-high roller mill, but using different roller configurations. Experimental diets were: (1) feed with corn fraction ground to 650 m using 2 sets of rolls (2-high), (2) feed with corn fraction ground to 495 m using 3 sets of rolls (3-high), (3) feed with corn fraction ground to 340 m using 4 sets of rolls in a fine grind configuration (4-high fine), and (4) feed with the corn fraction ground to 490 m using 4 sets of rolls in a coarse grind configuration (4-high coarse). The same roller mill was used for all configurations with the appropriate lower rolls completely open when using the 2 or 3 sets of rolls configurations.
In Exp. 2, 90 pigs (PIC 327 200, initially 27.0 lb) were randomly allotted to one of three diet comparisons to determine feed preference. The 3 diets used were from the 2-high roller mill configuration or the fine or coarse 4-high roller mill ground corn. Each pen contained 2 feeders, each containing 1 of the 3 treatment diets. The 3 diet comparisons tested were 2 vs. 4-high fine (1 vs. 3), 2-high vs. 4-high coarse (1 vs. 4), and4-high fine vs. 4-high coarse (3 vs. 4). Feeders were rotated once daily within each pen for the 7-d study. There were 5 pigs per pen, and 6 pens per treatment.
In Exp. 1, there were no differences (P > 0.05) in ADG, ADFI or F/G among roller mill configurations (Table 5). Similarly, no differences were observed (P > 0.05) for caloric efficiency or economics among roller mill configurations.
In Exp. 2, when given a choice, pigs consumed 67% (P < 0.05) of the diet containing corn ground through the 2-high roller mill compared to only 33% from the diet containing 4-high fine corn (Table 6). There was no difference (P > 0.05) in feed consumption of 2-high roller mill corn and the diet manufactured with the 4-high roller mill in a coarse configuration (50.3 to 49.7%, respectively). However pigs consumed 63% (P < 0.05) of the diet manufactured using the 4-high roller mill in a coarse configuration and only 37% from the diet using the 4-high mill in a fine grind configuration.
In the study, roller mill configuration had a significant impact on feed preference in nursery pigs, most likely as a result of differences in particle size. However, when nursery pigs did not have the choice between diets, there were no differences in gain, feed consumption, feed efficiency, or economics. Therefore, the study did not indicate a benefit in nursery pig performance or economic return when particle size was reduced below 650 m.
It is generally thought that as diets are ground to a smaller mean particle size, a linear improvement in nutrient utilization and pig performance will be observed. Research has demonstrated this benefit when particle size is reduced from 1,000 microns to approximately 600 microns. However, further reduction of particle size below 600 microns has not shown consistent benefits when fed to nursery pigs and has been reported to reduce feed intake and gain in finishing pigs. Generally, as grains are ground to a small mean particle size, the resulting increase in the amount of very fine particles has been shown to affect the diets palatability. The two primary manufacturing processes by which corn is ground include using a hammer or roller mill. Hammermilling benefits include the ability to grind a wide variety of ingredients to a very small particle size. A major disadvantage of using a hammermill is the increase in variation, as compared to that of roller mill-ground grain. The roller mill can grind grain to a much more consistent particle size with reduced operating costs, as compared to a hammermill. Previously, roller mill manufacturing technology did not allow the mean particle size to be reduced as fine as that of a hammermill. Recent advances in feed manufacturing technology allow producers to grind to a much finer particle size, using three or four sets of grindingrolls, while maintaining a consistent mean particle size and minimizing the amount of very fine particles. The objective of this series of experiments was to compare feed from various roller mill configurations on feed preference and performance of nursery pigs.
The Kansas State University Institutional Animal Care and Use Committee approved the protocols used in these experiments. The studies were conducted at the K-State Swine Teaching and Research Center and Segregated Early Weaning Facility in Manhattan, KS.
A total of 410 pigs were used in two experiments. In all experiments, pigs were randomly allotted to pens based on initial pig weight following weaning and were fed a common diet until reaching approximately 25 lb. All corn used in experimental diets was ground at a commercial feedmill (New Fashion Pork, Estherville, Iowa) using a 4-high roller mill (RMS Roller-Grinder, Harrisburg, SD) and subsequently transported to the O. H. Kruse Feed Technology Center at Kansas State University for manufacture of the complete diets. For treatments 1 and 2, corn was ground using two or three sets of rolls, respectively, and lower rolls were fully opened during processing to allow the ground grain to pass without any further particle size reduction. The roller mill configurations for each treatment were: (1) 2 sets of grinding rolls with roll gaps open to 0.035 and 0.025 in. (2-high); (2) 3 sets of grinding rolls with roll gaps open to 0.035, 0.025, and 0.020 in. (3-high); (3) 4 sets of grinding rolls with gaps open to 0.035, 0.025, 0.015, and 0.009 in. (4-high fine); and (4) 4 sets of grinding rolls with roll gaps open to 0.040, 0.030, 0.030, and 0.025 in. (4-high coarse). All grinding rolls had a 2% left spiral. The number of corrugations per inch increased with each set of rolls. The top rolls each had 6 corrugations per inch. The second set had 10 corrugations per inch. The third set had 1 roll with 12 and a second roll with 14 corrugations per inch. The fourth set of rolls had 1 roll with 14 and 1 roll with 16 corrugations per inch. Roll speed was offset and was 1,126 rpm for the fast roll (16.0-in. diameter sheave) and 763 rpm for the slow roll (23.6-in. diameter sheave). Corn feed rate was set based on a targeted 85% load on the roller mill. Roller mill performance data were collected during processing and included electricity consumption, grinding rate, and physical analysis of the grain as it progressed through the grinding rolls. These results are detailed in Gebhardt et al., 2015.
In Exp. 1, pens of pigs (320 DNA 400 200, initially 23.6 lb) were randomly allotted to 1 of 4 dietary treatments and fed for 21 d, with 16 pens per treatment and 5 pigs per pen. The 4 dietary treatments used the identical corn-soybean meal-based formulation that was manufactured from the same batch of ingredients (Table 1). Experimental diets were: (1) feed with the corn fraction ground to 650 m using 2 sets of rolls, (2) feed with corn fraction ground to 495 m using 3 sets of rolls, (3) feed with corn fraction ground to 340 m using 4 sets of rolls in a fine-grind configuration, and (4) feed with the corn fraction ground to 490 m using 4 sets of rolls in a coarse-grind configuration. Each pen contained a 4-hole, dry self-feeder and a nipple waterer to provide ad libitum access to feed and water. Pens had tri-bar floors and allowed approximately 2.7 ft2 /pig.Pig weights and feed disappearance were measured on d 0, 7, 14, and 21 to determine ADG, ADFI, and F/G.
Caloric feed efficiency was determined on both an ME and NE basis (NRC, 2012) and calculated by multiplying total feed intake energy content of the diet (kcal/lb) and dividing by total gain. Feed cost/pig, feed cost/lb gain, revenue per pig, and IOFC were calculated to determine economic implications. Diet costs were determined using the following ingredient and processing costs: corn = $3.75/bu, soybean meal = $286/ton, base grind/mix/delivery fee = $12.00/ton, supplemental grinding electricity based on roller mill configuration per ton of ground corn = 2-high ($0.00/ton), 3-high ($0.175/ ton), 4-high fine ($0.645/ton), 4-high coarse ($0.246/ton). Costs were derived from collection of electricity consumption and grinding rate performance data for the roller mill, which resulted in the 2-high configuration having the lowest electricity cost/ton ground corn. The supplemental grinding electricity cost was drawn from the average additional electricity cost above the 2-high baseline cost of $0.3663/ton of ground corn, which was added to the grind/mix/delivery fee. Feed cost/pig was determined by total feed intake diet cost ($/lb). Feed cost/lb gain was calculated using feed cost/pig divided by total gain. Revenue/pig was determined by total gain $0.60/lb live gain, and IOFC was calculated using revenue/pig feed cost/pig.
In Exp. 2, 90 pigs (PIC 327 1050, initially 27.0 lb) were randomly allotted to 1 of 3 dietary treatments with 6 pens per treatment and 5 pigs per pen. Experimental diets were fed for 7 d. Diets from treatments 1, 3, and 4 from Exp. 1 were used to determine the effect of grinding on feed preference. Each pen contained either two, 2-hole, dry self-feeders or two, 4-hole, dry self-feeders balanced among comparisons as well as a nipple waterer to provide ad libitum access to feed and water. Thus, the preference between 2 of the 3 diets could be tested within each pen. Feeders were rotated daily within each pen for the 7-d study. The 3 diet comparisons tested were 2-high vs. 4-high fine (1 vs. 3), 2-high vs. 4-high coarse (1 vs. 4), and 4-high fine vs. 4-high coarse (3 vs. 4). Pens had wire-mesh floors and allowed approximately 3.6 ft2 /pig. Feeders were weighed on d 0, 2, 4, and 7, and pig weights were collected on d 0 and 7 of the trial to determine ADG, ADFI, and F/G.
Complete diet samples were collected from feeders within treatment at multiple locations within feeder, subsampled, and submitted to Ward Laboratories, Inc. (Kearney, NE) for analysis of DM, CP, ADF, crude fiber, NFE, Ca, P, ether extract, ash, and starch. Particle size analysis was performed on all ground corn samples, and bulk density, angle of repose, and flowability index were determined at the Kansas State University Swine Lab. In addition, bulk density, angle of repose, and flowability index were determined for complete diets. Flowability was measured using a Flowdex device (Hanson Research, Chatsworth, CA), which measures flowability based on an ingredients ability to fall freely through a hole in the center of a disk. The flowability index is given as the hole diameter, expressed in millimeters, of the smallest hole disk 50 grams of an ingredient falls through freely on three consecutive attempts. Additionally, flowability was measured using angle of repose in which grain was placed in a cylinder on top of an 8.7 cm diameter pedestal. The cylinder was then lifted, which allowed the excess grain to fall freely. The height of the remaining grain was measured and used to calculate angle ofrepose. Particle size analysis was performed on all corn samples with and without a flow agent (Gilson Company, Inc., Lewis Center, OH) on a 13-sieve stack and pan, in the K-State Swine Lab on a Ro-Tap (W.S. Tyler, Mentor, OH) shaker for 15 minutes.
Data were analyzed as a completely randomized design using PROC GLIMMIX in SAS (SAS Institute, Inc., Cary, NC) with pen as the experimental unit for Exp. 1. For Exp. 2, feeder within pen was the experimental unit, and pen was included in the model as a random effect. The LSMEANS procedure of SAS was used to evaluate pen means (Exp. 1) and within pen mean difference in ADFI and was expressed as percentage of the total consumed for each diet (Exp. 2). Results were considered significant at P 0.05 and a trend at P 0.10.
As expected, chemical analysis of complete diets from both trials revealed no notable differences between treatments within experiment (Table 2). Corn ground using the 2-high configuration had the largest particle size and standard deviation (Table 3). Corn ground using the 3-high configuration and the 4-high coarse configuration had similar mean particle size, however the 3-high mill produced ground corn with a lower standard deviation. The 4-high fine configuration produced the finest particle size corn, as expected, and also had the lowest standard deviation. As particle size was reduced, surface area, expressed as cm2 /gram, increased.
Flowability using the Flowdex device resulted in similar flowability index scores for both 4-high configurations, whereas the 2-high configuration had an improved flowability index score, and the 3-high configuration had the most desirable flowability score (Table 3). The 4-high fine configuration had the least desirable angle of repose flowability score, whereas the 2- and 3-high configurations produced the most desirable ground corn based on angle of repose flowability. As expected, the corn produced from the 4-high fine configuration had the lightest bulk density, whereas the 2-high and 4-high coarse configurations ground corn had the heaviest bulk density.
Complete diets for Exp. 1 had similar Flowdex flowability scores for the 2-, 3-, and 4-high coarse configurations, whereas the 4-high fine configuration has the least desirable flowability score (Table 4). In Exp. 2, the 2-high configuration resulted in the lowest Flowdex flowability score, followed by the 4-high coarse configuration, and the 4-high fine configuration resulted in the least desirable flowability score. Angle of repose flowability resulted in similar results with the 2-high configuration having the most desirable flowability, and the 4-high fine configuration resulting in the least desirable flowability. As expected, complete diet bulk density was lightest for the 4-high fine configuration, and heaviest for the 2-high configuration.
In Exp. 1, there were no differences (P > 0.05) in ADG, ADFI, or F/G between roller mill configurations (Table 5). There also were no observed differences (P > 0.05) in caloric efficiency or economics among roller mill configurations.
In Exp. 2, pigs consumed more (67%; P < 0.05) of the diet containing 2-high roller mill manufactured corn than the diet with 4-high fine corn (33%; Table 6). There was no difference (P > 0.05) in feed consumption between the diet containing 2-high rollermill manufactured corn and the diet manufactured with corn from the 4-high roller mill in a coarse configuration (50.3 vs 49.7%, respectively). Pigs consumed more (63%; P < 0.05) of the diet manufactured using corn from the 4-high roller mill in a coarse configuration than the diet using corn from the 4-high mill in a fine grind configuration (37%).
In summary, nursery pigs preferred diets containing corn ground to 650 m compared to diets containing corn ground to 340 m, and preferred diets containing corn ground to 490 m compared to diets containing corn ground to 340 m. However, there was no observed difference in feed preference when pigs had access to diets containing corn ground to 650 m (2-high) compared to 490 m (4-high coarse). Roller mill ground corn did not show an improvement in growth performance below a particle size of 650 m in nursery pigs. A 4-high roller mill has the capability to produce a finer grind and reduce particle size below the level possible with previous roller mills and similar to a hammermill; however, our study did not indicate a benefit in nursery pig performance or economic return when particle size was reduced below 650 m.
This article was originally published in Kansas Agricultural Experiment Station Research Reports: Vol. 1: Iss. 7. https://doi.org/ 10.4148/2378-5977.1119. This is an Open Access article licensed under aCreative Commons Attribution 4.0 License.
do you really know raymond roller mill - raymond mill | agico cement
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 grinding - cement plant optimization
Highly energy intensive unit operation of size reduction in cement industry is intended to provide a homogeneous and super fine (3000-4000 Blain) cement. Grinding operation is monitored for following parameters to ensure objectivity and economy of operation.
Chemical analysis of cement, generally on hourly basis.
Product fineness, Blain surface and 45-micron residue.
Cement SO3, %
Grinding aid usage, grams/tonne
Cement moisture, %
Production rate, tonnes/hour
Operating hours as run factor in %
Specific power consumption (SPC) kWh/tonne.
Grindability and Power Consumption.Among various theories of comminution, most commonly accepted which is relevant to ball /tube mills is Bond's theory, which states that power input in comminution process is proportional to the surface generated in the process and the grindability of the material. To measure grindability, Bond developed 'Bond's Work Index' (BWI), a 'test mill' and a testing procedure for WI. With the help of this we can work out power required to grind a material from a given feed size to a product of given fineness.
Water Spray in Cement Mills.Water spray installed generally in second compartment of ball mill to control cement temperature. Cement discharge temperature should be kept below about 110oC but, the same time should allow some 60% dehydration of gypsum to optimize cement strength without excessive false set. Water spray is controlled with mill outlet gas or material temperature. A hardware interlock is recommended with mill main drive to avoid accidental spray in mill.
Grinding aids are generally added to the ball mill to reduce electrostatic agglomeration of fine particles and to reduce coating formation on grinding media which reduces grinding efficiency. The optimum addition rate should be determined carefully to enhance grinding efficiency. Grinding aids also serve to reduce coating problems in cement storage and enhances cement strengths.
Ball Mill.Ball mills with high efficiency separators have been used for cement grinding in cement plants all these years. Ball mill is a cylinder rotating at about 70-80% of critical speed on two trunnions in white metal bearings or slide shoe bearings for large capacity mills. Closed circuit ball mill with two compartments for coarse and fine grinding are generally found in cement plants for cement grinding. Compartments (filled with grinding media) are divided by a double diaphragm with flow control to utilize maximum mill length for effective grinding.
Grinding media contain balls of different sizes in designed proportions with large sizes in feed end and small sizes in discharge end. About 27 to 35 % volume of mill is filled with grinding media. Equilibrium charge is that charge where compensation for wear can be done by balls of one size only usually the largest size in the compartment. Grinding media could be made of forged steel, cast steel or even cast iron. To economize grinding media consumption, presently grinding media used are high chrome steel balls.
Mill shell is lined with lining plates to protect it from wear, high chrome steel liners are now commonly preferred to give longer life. Lifting liners are used to enhance impact in first compartment, where coarse grinding is dominated by impact. In second compartment which is longer in size (L>1.5D), classifying liners are used to ensure media classification along the length of mill with large size balls near mid partition and smaller balls at mill discharge end.
Ball mills are of 'bucket elevator' type for cement grinding, material is taken by conveyors to a separator where coarse was returned to the mill and fine sent to cyclone separator or bag filter for collection.
Different drive arrangement for ball mills are in existence. Commonly existing arrangement is mill drives with a girth gear and a pinion driven by motor with a gear box. Larger mills have a twin drives of half the ratings on either side of same girth gear. In central drive arrangement both the girth gear and pinion are avoided by connecting gear box output shaft directly to mill.
Closed circuit ball mills are existing with all types of separators () grit, mechanical and high efficiency in cement industries. Presently high efficiency separators are common to achieve maximum energy optimization. Brief description of separators is presented at the end.
Mill drive power or mill differential pressure to control mill feed rate.
Mill Sound level to control filling level inside mill with feed rate.
Mill outlet gas temperature.
Mill outlet material temperature.
Outlet gas flow determined from mill inlet and outlet drafts or flow meters installed.
Vertical Roller Mills.In Vertical Roller mill 2 - 4 rollers (lined with replaceable liners) turning on their axles press on a rotating grinding table (lined with replaceable liners) mounted on the yoke of a gear box. Pressure is exerted hydraulically. This mill also has a built in high efficiency separator above the rollers to reduce circulation loads and consequently reducing differential pressure across the mill.
The mill is started either with the rollers in lifted-up position, or with the hydro-pneumatic system at low pressure. In grinding mode, actual metal to metal contact should be prevented by limit switches or a mechanical stop and by consistent feed. In VRMs the material cycle time is usually less than a minute against several minutes for a ball mill or tube mill. Thus, control response should be accordingly faster. In case mill feed fails action should be taken within no more than 45 seconds or excessive vibration will cause mill shut-down. Moreover, the vertical mills are subject to vibrations if material is too dry to form a stable bed. Therefore, provision is made for controlled spray water inside the mill During mill operation magnetic separator and metal detector should be always functional to ensure to exclude tramp metal which can damage the grinding surfaces.
Roller Press.Roller press consists of two rollers lined with wear resistant material. One roller is fixed and the other one is movable to exert pressure, applied hydraulically. A roller press looks similar to a roll crusher. However, the pressure exerted between rollers is very high - of the order of 400 kg/cm2 as compared to roll crushers. Feed is fed over the total width of the rollers by a central chute. About 30 % material gets pulverized to the required product fineness. Roller press output pre-ground material is fed to a ball mill operating in closed circuit. Ball mill required is smaller in size and larger grinding balls are no more required.
Several types of separator are employed in mill circuits and there are numerous variations of each type:
Mechanical separators Mill discharge material is fed onto a rotating dispersion plate whence it is spread off into a rising air stream. Coarse particles either fall directly from the dispersion plate or are rejected between the auxiliary fan blades and the control valve. Fine dust is taken along with main fan flow and is detrained as the gas flows downwards loses momentum (velocity) and diversion through the return vanes. Controlling parameters are the number of auxiliary blades, the clearance between auxiliary blades and control valve, and the radial position of the main fan blades
High efficiency separators, 3rd generation separators were introduced to improve the mechanical separator's fines recovery efficiency. Examples of these separators are O-Sepa (FLSmidth), Sepol (ThyssenKrupp) A simplified process flow these separators is as follows. Material is fed onto a rotating dispersion plate via air slide, whence it is dispersed off into the classifying air stream. Separator loading is recommended to be up to about 2.5kg feed/M3 air flow. Vortex is formed by the rotor which classifies particles between centrifugal force and the inward air flow. The fine fraction exits upwards/downwards with the air sucked by ID fan passes through cyclone separators or a bag filter for product collection, while the coarse fraction falls and is discharged from the bottom and send back to mill for regrinding. Fineness is controlled by rotor speed (increasing speed increases fineness).