senya scc2818dot concrete/cement micro conveyor - senya crushers
Senya Tech provides cone crusher, vertical shaft impact crusher, impact crusher, jaw crusher,which are widely used for the primary, secondary and tertiary hard-rock crushing for stone-processing line and sand-making line.
Senya Tech provides MP Mobile Crushing Plants and Portable Crushing Plants, which can move to the source of stones with high efficiency, flexibility and low costs, and compose a complicated application. It includes jaw crusher, impact crusher, cone crusher, vibrating screen and other combination type, which can be transported wholly-assembled and apart.
Senya Tech offer a wide range of mobile rock crushers, scalpers&screeners, both tracked and wheeled, including jaw, cone&impact crushers.Mobile crushing and screening equipments developed by Senya are used widely in mining, crushing, construction waste recycling fields etc.
5 types of concrete crushers for recycling concrete blocks | fote machinery
Concrete block often appears after building and bridge demolition, which will cause problems like pollutions and land waste. There are mainly 5 types of concrete crushers like portable concrete crusher, mobile concrete crusher, small concrete crusher, excavator concrete crusher and bucket crusher, so you have to choose the right crushing machine according to your own situation.
A portable stone crusher, a wheeled-mounted crushing machine, is a perfect machine for processing concrete waste because of its strong flexibility. Concrete recycling manufacturers always know that if they choose to set up a fixed crushing line, they have to pay more time, money for labor and transportation.
A portable crusher can load various fixed crusher machines like fixed jaw crusher, impact rock crusher, hydraulic cone crusher, etc. Therefore, it is a mobile crushing plant integrating crushing equipment, conveyor, and power control equipment. It can last for 20,000 hours under difficult conditions while 30,000 hours under normal conditions, and then needs to be overhauled so that its service life can be extended.
This Indian customer purchased FTM938HD80 portable jaw crusher, portable impact crusher, and portable stone screener. These machines can not only produce a wonderful cubical shape of products but greatly reduce labor and transportation cost. The original plan was to require three people to spend about half a month fully installing a fixed crushing production line. In addition to transportation costs, the total cost was really expensive.
It can be seen from the table that Fote portable concrete crusher helps customers save costs, improves production efficiency, and brings objective profits to customers. If you are interested in this equipment, you can consult and quote to obtain detailed information about the equipment.
Compared with the tire-type concrete crusher, the unique feature of the mobile crusher is that it uses a crawler or tracked mounting way, which makes it 100 percent free movement and to be operated by remote control.
This British customer ordered a mobile jaw breaker and mobile impact in December last year, but due to the covid-19, he couldn't come to the factory to buy it in person.
The sales team of FTM Manufacturer introduced him to detailed equipment information online and provided him with the best solution based on its output, size and other requirements. After talking, he was very satisfied and then purchased machines online in March 2020.
Small concrete crushers are mainly used for crushing with small output, and most of them are jaw crushers with fixed and mobile types. The feed size of the small concrete crusher is not very large, so it can only process smaller concrete materials.
Excavator concrete crusher can make it easy to process concrete mixed with mud and scrap. It is made of high-strength wear-resistant steel, which can be directly installed or hooked to the excavator, which greatly improves the versatility of the excavator.
It is mostly used for the removal of concrete slabs, walls and bridge decks. The jaws of this crusher can be operated without any hydraulic pressure.
The crushing process depends on the pressing forces created by movable front jaw and fixed rear jaw, which can separate the concrete from the steel bar and crush the concrete at the same time.
It is also an ideal attachment for recycling different materials. You can just mount the crusher on a wheel loader to demonstrate the outstanding performance of this attachment on reinforced concrete. Usually, one of the most difficult materials to recycle is wood scraps mixed with metal parts.
As a leading mining machinery manufacturer and exporter in China, we are always here to provide you with high quality products and better services. Welcome to contact us through one of the following ways or visit our company and factories.
Based on the high quality and complete after-sales service, our products have been exported to more than 120 countries and regions. Fote Machinery has been the choice of more than 200,000 customers.
impact crusher - an overview | sciencedirect topics
The impact crusher (typically PE series) is widely used and of high production efficiency and good safety performance. The finished product is of cube shape and the tension force and crack is avoided. Compared with hammer crusher, the impact crusher is able to fully utilize the high-speed impact energy of entire rotor. However, due to the crushing board that is easy to wear, it is also limited in the hard material crushing. The impact crusher is commonly used for the crushing of limestone, coal, calcium carbide, quartz, dolomite, iron pyrites, gypsum, and chemical raw materials of medium hardness. Effect of process conditions on the production capacity of crushed materials is listed in Table8.10.
Depending on the size of the debris, it may either be ready to enter the recycling process or need to be broken down to obtain a product with workable particle sizes, in which case hydraulic breakers mounted on tracked or wheeled excavators are used. In either case, manual sorting of large pieces of steel, wood, plastics and paper may be required, to minimise the degree of contamination of the final product.
The three types of crushers most commonly used for crushing CDW materials are the jaw crusher, the impact crusher and the gyratory crusher (Figure 4.4). A jaw crusher consists of two plates, with one oscillating back and forth against the other at a fixed angle (Figure 4.4(a)) and it is the most widely used in primary crushing stages (Behera etal., 2014). The jaw crusher can withstand large and hard-to-break pieces of reinforced concrete, which would probably cause the other crushing machines to break down. Therefore, the material is initially reduced in jaw crushers before going through any other crushing operation. The particle size reduction depends on the maximum and minimum size of the gap at the plates (Hansen, 2004).
An impact crusher breaks the CDW materials by striking them with a high-speed rotating impact, which imparts a shearing force on the debris (Figure 4.4(b)). Upon reaching the rotor, the debris is caught by steel teeth or hard blades attached to the rotor. These hurl the materials against the breaker plate, smashing them into smaller particle sizes. Impact crushers provide better grain-size distribution of RA for road construction purposes, and they are less sensitive to material that cannot be crushed, such as steel reinforcement.
Generally, jaw and impact crushers exhibit a large reduction factor, defined as the ratio of the particle size of the input to that of the output material. A jaw crusher crushes only a small proportion of the original aggregate particles but an impact crusher crushes mortar and aggregate particles alike and thus generates a higher amount of fine material (OMahony, 1990).
Gyratory crushers work on the same principle as cone crushers (Figure 4.4(c)). These have a gyratory motion driven by an eccentric wheel. These machines will not accept materials with a large particle size and therefore only jaw or impact crushers should be considered as primary crushers. Gyratory and cone crushers are likely to become jammed by fragments that are too large or too heavy. It is recommended that wood and steel be removed as much as possible before dumping CDW into these crushers. Gyratory and cone crushers have advantages such as relatively low energy consumption, a reasonable amount of control over the particle size of the material and production of low amounts of fine particles (Hansen, 2004).
For better control of the aggregate particle size distribution, it is recommended that the CDW should be processed in at least two crushing stages. First, the demolition methodologies used on-site should be able to reduce individual pieces of debris to a size that the primary crusher in the recycling plant can take. This size depends on the opening feed of the primary crusher, which is normally bigger for large stationary plants than for mobile plants. Therefore, the recycling of CDW materials requires careful planning and communication between all parties involved.
A large proportion of the product from the primary crusher can result in small granules with a particle size distribution that may not satisfy the requirements laid down by the customer after having gone through the other crushing stages. Therefore, it should be possible to adjust the opening feed size of the primary crusher, implying that the secondary crusher should have a relatively large capacity. This will allow maximisation of coarse RA production (e.g., the feed size of the primary crusher should be set to reduce material to the largest size that will fit the secondary crusher).
The choice of using multiple crushing stages mainly depends on the desired quality of the final product and the ratio of the amounts of coarse and fine fractions (Yanagi etal., 1998; Nagataki and Iida, 2001; Nagataki etal., 2004; Dosho etal., 1998; Gokce etal., 2011). When recycling concrete, a greater number of crushing processes produces a more spherical material with lower adhered mortar content (Pedro etal., 2015), thus providing a superior quality of material to work with (Lotfi etal., 2017). However, the use of several crushing stages has some negative consequences as well; in addition to costing more, the final product may contain a greater proportion of finer fractions, which may not always be a suitable material.
Reduction of the broken rock material, or oversized gravel material, to an aggregate-sized product is achieved by various types of mechanical crusher. These operations may involve primary, secondary and even sometimes tertiary phases of crushing. There are many different types of crusher, such as jaw, gyratory, cone (or disc) and impact crushers (Fig. 15.9), each of which has various advantages and disadvantages according to the properties of the material being crushed and the required shape of the aggregate particles produced.
Fig. 15.9. Diagrams to illustrate the basic actions of some types of crusher: solid shading highlights the hardened wear-resistant elements. (A) Single-toggle jaw crusher, (B) disc or gyrosphere crusher, (C) gyratory crusher and (D) impact crusher.
It is common, but not invariable, for jaw or gyratory crushers to be utilised for primary crushing of large raw feed, and for cone crushers or impact breakers to be used for secondary reduction to the final aggregate sizes. The impact crushing machines can be particularly useful for producing acceptable particle shapes (Section 15.5.3) from difficult materials, which might otherwise produce unduly flaky or elongated particles, but they may be vulnerable to abrasive wear and have traditionally been used mostly for crushing limestone.
Reduction of the broken rock material, or oversized gravel material, to an aggregate-sized product is achieved by various types of mechanical crusher. These operations may involve primary, secondary and even sometimes tertiary phases of crushing. There are many different types of crusher, such as jaw, gyratory, cone (or disc) and impact crushers (Figure 16.8), each of which has various advantages and disadvantages according to the properties of the material being crushed and the required shape of the aggregate particles produced.
Fig. 16.8. Diagrams to illustrate the basic actions of some types of crusher: solid shading highlights the hardened wear-resistant elements (redrawn, adapted and modified from Ref. 39). (a) Single-toggle jaw crusher, (b) disc or gyrosphere crusher, (c) gyratory crusher, and (d) impact crusher.
It is common, but not invariable, for jaw or gyratory crushers to be utilised for primary crushing of large raw feed, and for cone crushers or impact breakers to be used for secondary reduction to the final aggregate sizes. The impact crushing machines can be particularly useful for producing acceptable particle shapes (section 16.5.3) from difficult materials, which might otherwise produce unduly flaky or elongated particles, but they may be vulnerable to abrasive wear and have traditionally been used mostly for crushing limestone.
The main sources of RA are either from construction and ready mixed concrete sites, demolition sites or from roads. The demolition sites produce a heterogeneous material, whereas ready mixed concrete or prefabricated concrete plants produce a more homogeneous material. RAs are mainly produced in fixed crushing plant around big cities where CDWs are available. However, for roads and to reduce transportation cost, mobile crushing installations are used.
The materiel for RA manufacturing does not differ from that of producing NA in quarries. However, it should be more robust to resist wear, and it handles large blocks of up to 1m. The main difference is that RAs need the elimination of contaminants such as wood, joint sealants, plastics, and steel which should be removed with blast of air for light materials and electro-magnets for steel. The materials are first separated from other undesired materials then treated by washing and air to take out contamination. The quality and grading of aggregates depend on the choice of the crusher type.
Jaw crusher: The material is crushed between a fixed jaw and a mobile jaw. The feed is subjected to repeated pressure as it passes downwards and is progressively reduced in size until it is small enough to pass out of the crushing chamber. This crusher produces less fines but the aggregates have a more elongated form.
Hammer (impact) crusher: The feed is fragmented by kinetic energy introduced by a rotating mass (the rotor) which projects the material against a fixed surface causing it to shatter causing further particle size reduction. This crusher produces more rounded shape.
The type of crusher and number of processing stages have considerable influence on the shape and size of RA. In general, for the same size, RAs tend to be coarser, more porous and rougher than NAs, due to the adhered mortar content (Dhir etal., 1999). After the primary crushing, which is normally performed using jaw crushers (Fong etal., 2004), it is preferable to adopt a secondary crushing stage (with cone crushers or impact crushers) (CCANZ, 2011) to further reduce the size of the CDW, producing more regularly shaped particles (Barbudo etal., 2012; Ferreira etal., 2011; Fonseca etal., 2011; Pedro etal., 2014, 2015; Gonzlez-Fonteboa and Martnez-Abella, 2008; Maultzsch and Mellmann, 1998; Dhir and Paine, 2007; Chidiroglou etal., 2008).
CDW that is subjected to a jaw crushing stage tends to result only in flatter RA (Ferreira etal., 2011; Fonseca etal., 2011; Hendriks, 1998; Tsoumani etal., 2015). It is possible to produce good-quality coarse RA within the specified size range by adjusting the crusher aperture (Hansen, 1992). In addition, the number of processing stages needs to be well thought out to ensure that the yield of coarse RA is not affected and that the quantity of fine RA is kept to the minimum (Angulo etal., 2004). This is because the finer fraction typically exhibits lower quality, as it accumulates a higher amount of pulverised old mortar (Etxeberria etal., 2007b; Meller and Winkler, 1998). Fine RA resulting from impact crushers tends to exhibit greater angularity and higher fineness modulus compared with standard natural sands (Lamond etal., 2002; Hansen, 1992; Buyle-Bodin and Hadjieva-Zaharieva, 2002).
One of the commonly known issues related to the use of RCA is its ability to generate a considerable amount of fines when the material is used (Thomas etal., 2016). As the RCA particles are moved around, they impact against one another, leading to the breakage of the friable adhered mortar, which may give rise to some technical problems such as an increase in the water demand of concrete mixes when used as an NA replacement (Thomas etal., 2013a,b; Poon etal., 2007).
The coarse fraction of RMA tends to show a higher shape index owing to the shape of the original construction material (e.g., perforated ceramic bricks) (De Brito etal., 2005). This can pose a problem in future applications as RMA may not compact as efficiently as RCA or NA (Khalaf and DeVenny, 2005). Its shape index may be reduced if the material is successively broken down to a lower particle size (De Brito etal., 2005).
Impact crushers (e.g., hammer mills and impact mills) employ sharp blows applied at high speed to free-falling rocks where comminution is by impact rather than compression. The moving parts are beaters, which transfer some of their kinetic energy to the ore particles upon contact. Internal stresses created in the particles are often large enough to cause them to shatter. These forces are increased by causing the particles to impact upon an anvil or breaker plate.
There is an important difference between the states of materials crushed by pressure and by impact. There are internal stresses in material broken by pressure that can later cause cracking. Impact causes immediate fracture with no residual stresses. This stress-free condition is particularly valuable in stone used for brick-making, building, and roadmaking, in which binding agents (e.g., tar) are subsequently added. Impact crushers, therefore, have a wider use in the quarrying industry than in the metal-mining industry. They may give trouble-free crushing on ores that tend to be plastic and pack when the crushing forces are applied slowly, as is the case in jaw and gyratory crushers. These types of ore tend to be brittle when the crushing force is applied instantaneously by impact crushers (Lewis et al., 1976).
Impact crushers are also favored in the quarry industry because of the improved product shape. Cone crushers tend to produce more elongated particles because of their ability to pass through the chamber unbroken. In an impact crusher, all particles are subjected to impact and the elongated particles, having a lower strength due to their thinner cross section, would be broken (Ramos et al., 1994; Kojovic and Bearman, 1997).
Figure 6.23(a) shows the cross section of a typical hammer mill. The hammers (Figure 6.23(b)) are made from manganese steel or nodular cast iron containing chromium carbide, which is extremely abrasion resistant. The breaker plates are made of the same material.
The hammers are pivoted so as to move out of the path of oversize material (or tramp metal) entering the crushing chamber. Pivoted (swing) hammers exert less force than they would if rigidly attached, so they tend to be used on smaller impact crushers or for crushing soft material. The exit from the mill is perforated, so that material that is not broken to the required size is retained and swept up again by the rotor for further impacting. There may also be an exit chute for oversize material which is swept past the screen bars. Certain design configurations include a central discharge chute (an opening in the screen) and others exclude the screen, depending on the application.
The hammer mill is designed to give the particles velocities of the order of that of the hammers. Fracture is either due to impact with the hammers or to the subsequent impact with the casing or grid. Since the particles are given high velocities, much of the size reduction is by attrition (i.e., particle on particle breakage), and this leads to little control on product size and a much higher proportion of fines than with compressive crushers.
The hammers can weigh over 100kg and can work on feed up to 20cm. The speed of the rotor varies between 500 and 3,000rpm. Due to the high rate of wear on these machines (wear can be taken up by moving the hammers on the pins) they are limited in use to relatively non-abrasive materials. They have extensive use in limestone quarrying and in the crushing of coal. A great advantage in quarrying is the fact that they produce a relatively cubic product.
A model of the swing hammer mill has been developed for coal applications (Shi et al., 2003). The model is able to predict the product size distribution and power draw for given hammer mill configurations (breaker gap, under-screen orientation, screen aperture) and operating conditions (feed rate, feed size distribution, and breakage characteristics).
For coarser crushing, the fixed hammer impact mill is often used (Figure 6.24). In these machines the material falls tangentially onto a rotor, running at 250500rpm, receiving a glancing impulse, which sends it spinning toward the impact plates. The velocity imparted is deliberately restricted to a fraction of the velocity of the rotor to avoid high stress and probable failure of the rotor bearings.
The fractured pieces that can pass between the clearances of the rotor and breaker plate enter a second chamber created by another breaker plate, where the clearance is smaller, and then into a third smaller chamber. The grinding path is designed to reduce flakiness and to produce cubic particles. The impact plates are reversible to even out wear, and can easily be removed and replaced.
The impact mill gives better control of product size than does the hammer mill, since there is less attrition. The product shape is more easily controlled and energy is saved by the removal of particles once they have reached the size required.
Large impact crushers will reduce 1.5m top size ROM ore to 20cm, at capacities of around 1500th1, although units with capacities of 3000th1 have been manufactured. Since they depend on high velocities for crushing, wear is greater than for jaw or gyratory crushers. Hence impact crushers are not recommended for use on ores containing over 15% silica (Lewis et al., 1976). However, they are a good choice for primary crushing when high reduction ratios are required (the ratio can be as high as 40:1) and the ore is relatively non-abrasive.
Developed in New Zealand in the late 1960s, over the years it has been marketed by several companies (Tidco, Svedala, Allis Engineering, and now Metso) under various names (e.g., duopactor). The crusher is finding application in the concrete industry (Rodriguez, 1990). The mill combines impact crushing, high-intensity grinding, and multi-particle pulverizing, and as such, is best suited in the tertiary crushing or primary grinding stage, producing products in the 0.0612mm size range. It can handle feeds of up to 650th1 at a top size of over 50mm. Figure 6.22 shows a Barmac in a circuit; Figure 6.25 is a cross-section and illustration of the crushing action.
The basic comminution principle employed involves acceleration of particles within a special ore-lined rotor revolving at high speed. A portion of the feed enters the rotor, while the remainder cascades to the crushing chamber. Breakage commences when rock enters the rotor, and is thrown centrifugally, achieving exit velocities up to 90ms1. The rotor continuously discharges into a highly turbulent particle cloud contained within the crushing chamber, where reduction occurs primarily by rock-on-rock impact, attrition, and abrasion.
This crusher developed by Jaques (now Terex Mineral Processing Solutions) has several internal chamber configurations available depending on the abrasiveness of the ore. Examples include the Rock on Rock, Rock on Anvil and Shoe and Anvil configurations (Figure 6.26). These units typically operate with 5 to 6 steel impellers or hammers, with a ring of thin anvils. Rock is hit or accelerated to impact on the anvils, after which the broken fragments freefall into the discharge chute and onto a product conveyor belt. This impact size reduction process was modeled by Kojovic (1996) and Djordjevic et al. (2003) using rotor dimensions and speed, and rock breakage characteristics measured in the laboratory. The model was also extended to the Barmac crushers (Napier-Munn et al., 1996).
Figure 9.1 shows common aluminum oxide-based grains. Also called corundum, alumina ore was mined as early as 2000 BC in the Greek island of Naxos. Its structure is based on -Al2O3 and various admixtures. Traces of chromium give alumina a red hue, iron makes it black, and titanium makes it blue. Its triagonal system reduces susceptibility to cleavage. Precious grades of Al2O3 are used as gemstones, and include sapphire, ruby, topaz, amethyst, and emerald.
Charles Jacobs (1900), a principal developer, fused bauxite at 2200C (4000F) before the turn of the 20th century. The resulting dense mass was crushed into abrasive particles. Presently, alumina is obtained by smelting aluminum alloys containing Al2O3 in electric furnaces at around 1260C (2300F), a temperature at which impurities separate from the solution and aluminum oxide crystallizes out. Depending upon the particular process and chemical composition there are a variety of forms of aluminum oxide. The poor thermal conductivity of alumina (33.5W/mK) is a significant factor that affects grinding performance. Alumina is available in a large range of grades because it allows substitution of other oxides in solid solution, and defect content can be readily controlled.
For grinding, lapping, and polishing bearing balls, roller races, and optical glasses, the main abrasive employed is alumina. Its abrasive characteristics are established during the furnacing and crushing operations, so very little of what is accomplished later significantly affects the features of the grains.
Aluminum oxide is tougher than SiC. There are four types of gradations for toughness. The toughest grain is not always the longest wearing. A grain that is simply too tough for an application will become dull and will rub the workpiece, increasing the friction, creating heat and vibrations. On the other hand, a grain that is too friable will wear away rapidly, shortening the life of the abrasive tool. Friability is a term used to describe the tendency for grain fractures to occur under load. There is a range of grain toughness suitable for each application. The white friable aluminum oxide is almost always bonded by vitrification. It is the main abrasive used in tool rooms because of its versatility for a wide range of materials. In general, the larger the crystals, the more friable the grain. The slower the cooling process, the larger are the crystals. To obtain very fine crystals, the charge is cooled as quickly as possible, and the abrasive grain is fused in small pigs of up to 2ton. Coarse crystalline abrasive grains are obtained from 5 to 6ton pigs allowed to cool in the furnace shell.
The raw material, bauxite, containing 8590% alumina, 25% TiO2, up to 10% iron oxide (Fe2O3), silica, and basic oxides, is fused in an electric-arc furnace at 2600C (4700F). The bed of crushed and calcined bauxite, mixed with coke and iron to remove impurities, is poured into the bottom of the furnace where a carbon starter rod is laid down. A couple of large vertical carbon rods are then brought down to touch and a heavy current applied. The starter rod is rapidly consumed, by which time the heat melts the bauxite, which then becomes an electrolyte. Bauxite is added over several hours to build up the volume of melt. Current is controlled by adjusting the height of the electrodes, which are eventually consumed in the process.
After cooling, the alumina is broken up and passed through a series of hammer, beater, crush, roller, and/or ball mills to reduce it to the required grain size and shape, producing either blocky or thin splintered grains. After milling, the product is sieved to the appropriate sizes down to about 40 m (#400). The result is brown alumina containing typically 3% TiO2. Increased TiO2 content increases toughness while reducing hardness. Brown alumina has a Knoop hardness of 2090 and a medium friability.
Electrofused alumina is also made using low-soda Bayer process alumina that is more than 99% pure. The resulting alumina grain is one of the hardest, but also the most friable, of the alumina family providing a cool cutting action. This abrasive in a vitrified bond is, therefore, suitable for precision grinding.
White aluminum oxide is one of the most popular grades for micron-size abrasive. To produce micron sizes, alumina is ball-milled or vibro-milled after crushing and then traditionally separated into different sizes using an elutriation process. This consists of passing abrasive slurry and water through a series of vertical columns. The width of the columns is adjusted to produce a progressively slower vertical flow velocity from column to column. Heavier abrasive settles out in the faster flowing columns while lighter particles are carried over to the next. The process is effective down to about 5 m and is also used for micron sizing of SiC. Air classification has also been employed.
White 99% pure aluminum oxide, called mono-corundum, is obtained by sulfidation of bauxite, which outputs different sizes of isometric corundum grains without the need for crushing. The crystals are hard, sharp, and have better cleavage than other forms of aluminum oxides, which qualifies it for grinding hardened steels and other tough and ductile materials. Fine-grained aluminum oxide with a good self-sharpening effect is used for finishing hardened and high-speed steels, and for internal grinding.
Not surprisingly, since electrofusion technology has been available for the last one hundred years, many variations in the process exist both in terms of starting compositions and processing routes. For example:
Red-brown or gray regular alumina. Contains 9193% Al2O3 and has poor cleavage. This abrasive is used in resinoid and vitrified bonds and coated abrasives for rough grinding when the risk of rapid wheel wear is low.
Chrome addition. Semi-fine aloxite, pink with 0.5% chromium oxide (Cr2O3), and red with 15% Cr2O3, lies between common aloxite, having less than 95% Al2O3 and more than 2% TiO2, and fine aloxite, which has more than 95% Al2O3 and less than 2% TiO2. The pink grain is slightly harder than white alumina, while the addition of a small amount of TiO2 increases its toughness. The resultant product is a medium-sized grain available in elongated, or blocky but sharp, shapes. Ruby alumina has a higher chrome oxide content of 3% and is more friable than pink alumina. The grains are blocky, sharp edged, and cool cutting, making them popular for tool room and dry grinding of steels, e.g., ice skate sharpening. Vanadium oxide has also been used as an additive giving a distinctive green hue.
Zirconia addition. Aluminazirconia is obtained during the production process by adding 1040% ZrO2 to the alumina. There are at least three different aluminazirconia compositions used in grinding wheels: 75% Al2O3 and 25% ZrO2, 60% Al2O3 and 40% ZrO2, and finally, 65% Al2O3, 30% ZrO2, and 5% TiO2. The manufacture usually includes rapid solidification to produce a fine grain and tough structure. The resulting abrasives are fine grain, tough, highly ductile, and give excellent life in medium to heavy stock removal applications and grinding with high pressures, such as billet grinding in foundries.
Titania addition. Titaniaaloxite, containing 95% Al2O3 and approximately 3% Ti2O3, has better cutting ability and improved ductility than high-grade bauxite common alumina. It is recommended when large and variable mechanical loads are involved.
Single crystal white alumina. The grain growth is carefully controlled in a sulfide matrix and is separated by acid leaching without crushing. The grain shape is nodular which aids bond retention, avoiding the need for crushing and reducing mechanical defects from processing.
Post-fusion processing methods. This type of particle reduction method can greatly affect grain shape. Impact crushers such as hammer mills create a blocky shape while roll crushers cause splintering. It is possible, using electrostatic forces to separate sharp shapes from blocky grains, to provide grades of the same composition but with very different cutting actions.
The performance of the abrasive can also be altered by heat treatment, particularly for brown alumina. The grit is heated to 11001300 C (20152375 F), depending on the grit size, in order to anneal cracks and flaws created by the crushing process. This can enhance toughness by 2540%.
Finally, several coating processes exist to improve bonding of the grains in the grinding wheel. Red Fe2O3 is applied at high temperatures to increase the surface area for better bonding in resin cut-off wheels. Silane is applied for some resin bond wheel applications to repel coolant infiltration between the bond and abrasive grit, and thus protect the resin bond.
A limitation of electrofusion is that the resulting abrasive crystal structure is very large; an abrasive grain may consist of only one to three crystals. Consequently, when grain fracture occurs, the resulting particle loss may be a large proportion of the whole grain. This results in inefficient grit use. One way to avoid this is to dramatically reduce the crystal size.
The earliest grades of microcrystalline grits were produced as early as 1963 (Ueltz, 1963) by compacting a fine-grain bauxite slurry, granulating to the desired grit size, and sintering at 1500C (2735F). The grain shape and aspect ratio could be controlled by extruding the slurry.
One of the most significant developments since the invention of the Higgins furnace was the release in 1986, by the Norton Company, of seeded gel (SG) abrasive (Leitheiser and Sowman, 1982; Cottringer et al., 1986). This abrasive was a natural outcome of the wave of technology sweeping the ceramics industry at that time to develop high strength engineering ceramics using chemical precipitation methods. This class of abrasives is often termed ceramic. SG is produced by a chemical process. In a precursor of boehmite, MgO is first precipitated to create 50-m-sized aluminamagnesia spinel seed crystals. The resulting gel is dried, granulated to size, and sintered at 1200C (2200F). The resulting grains are composed of a single-phase -alumina structure with a crystalline size of about 0.2m. Defects from crushing are avoided; the resulting abrasive is unusually tough but self-sharpening because fracture now occurs at the micron level.
With all the latest technologies, it took significant time and application knowledge to understand how to apply SG. The abrasive was so tough that it had to be blended with regular fused abrasives at levels as low as 5% to avoid excessive grinding forces. Typical blends are now five SGs (50%), three SGs (30%), and one SG (10%). These blended abrasive grades can increase wheel life by up to a factor of 10 over regular fused abrasives, although manufacturing costs are higher.
In 1981, prior to the introduction of SG, the 3M Co. introduced a solgel abrasive material called Cubitron for use in coated abrasive fiber discs (Bange and Orf, 1998). This was a submicron chemically precipitated and sintered material but, unlike SG, had a multiphase composite structure that did not use seed grains to control crystalline size. The value of the material for grinding wheel applications was not recognized until after the introduction of SG. In the manufacture of Cubitron, alumina is co-precipitated with various modifiers such as magnesia, yttria, lanthana, and neodymia to control microstructural strength and surface morphology upon subsequent sintering. For example, one of the most popular materials, Cubitron 321, has a microstructure containing submicron platelet inclusions which act as reinforcements somewhat similar to a whisker-reinforced ceramic (Bange and Orf, 1998).
Direct comparison of the performance of SG and Cubitron is difficult because the grain is merely one component of the grinding wheel. SG is harder (21GPa) than Cubitron (19GPa). Experimental evidence suggests that wheels made from SG have longer life, but Cubitron is freer cutting. Cubitron is the preferred grain in some applications from a cost/performance viewpoint. Advanced grain types are prone to challenge from a well-engineered, i.e., shape selected, fused grain that is the product of a lower cost, mature technology. However, it is important to realize that the wheel cost is often insignificant compared to other grinding process costs in the total cost per part.
The SG grain shape can be controlled by extrusion. Norton has taken this concept to an extreme and in 1999 introduced TG2 (extruded SG) grain in a product called ALTOS. The TG2 grains have the appearance of rods with very long aspect ratios. The resulting packing characteristics of these shapes in a grinding wheel create a high strength, lightweight structure with porosity levels as high as 70% or even greater. The grains touch each other at only a few points, where a bond also concentrates in the same way as a spot weld. The product offers potential for higher stock removal rates and higher wheelspeeds due to the strength and density of the resulting wheel body (Klocke and Muckli, 2000).
Recycling of concrete involves several steps to generate usable RCA. Screening and sorting of demolished concrete from C&D debris is the first step of recycling process. Demolished concrete goes through different crushing processes to acquire desirable grading of recycled aggregate. Impact crusher, jaw crusher, cone crusher or sometimes manual crushing by hammer are preferred during primary and secondary crushing stage of parent concrete to produce RA. Based on the available literature step by step flowchart for recycling of aggregate is represented in Fig. 1. Some researchers have also developed methods like autogenous cleaning process , pre-soaking treatment in water , chemical treatment, thermal treatment , microwave heating method  and mechanical grinding method for removing adhered mortar to obtain high quality of RA. Depending upon the amount of attached mortar, recycled aggregate has been classified into different categories as shown in Fig. 2.
Upon arrival at the recycling plant, CDW may either enter directly into the processing operation or need to be broken down to obtain materials with workable particle sizes, in which case hydraulic breakers mounted on tracked or wheeled excavators are used. In either case, manual sorting of large pieces of steel, wood, plastics and paper may be required, to minimize the degree of contamination.
The three types of crushers most used for crushing CDW are jaw, impact, and gyratory crushers (Fig.8). A jaw crusher consists of two plates fixed at an angle (Fig.8a); one plate remains stationary while the other oscillates back and forth relative to it, crushing the material passing between them. This crusher can withstand large pieces of reinforced concrete, which would probably cause other types of crushers to break down. Therefore, the material is initially reduced in jaw crushers before going through other types. The particle size reduction depends on the maximum and minimum size of the gap at the plates. Jaw crushers were found to produce RA with the most suitable grain-size distribution for concrete production (Molin etal., 2004).
An impact crusher breaks CDW by striking them with a high speed rotating impact, which imparts a shearing force on the debris (Fig.8b). Materials fall onto the rotor and are caught by teeth or hard steel blades fastened to the rotor, which hurl them against the breaker plate, smashing them to smaller-sized particles. Impact crushers provide better grain-size distribution of RA for road construction purposes and are less sensitive to material that cannot be crushed (i.e. steel reinforcement).
Gyratory crushers, which work on the same principle as cone crushers (Fig.8c), exhibit a gyratory motion driven by an eccentric wheel and will not accept materials with large particle sizes as they are likely to become jammed. However, gyratory and cone crushers have advantages such as relatively low energy consumption, reasonable amount of control over particle size and production of low amount of fine particles.
Generally, jaw and impact crushers have a large reduction factor, defined as the relationship between the input's particle size and that of the output. A jaw crusher crushes only a small proportion of the original aggregate particles but an impact crusher crushes mortar and aggregate particles alike, and thus may generate twice the amount of fines for the same maximum size of particle (O'Mahony, 1990).
In order to produce RA with predictable grading curve, it is better to process debris in two crushing stages, at least. It may be possible to consider a tertiary crushing stage and further, which would undoubtedly produce better quality coarse RA (i.e. less adhered mortar and with a rounder shape). However, concrete produced with RA subjected to a tertiary crushing stage may show only slightly better performance than that made with RA from a secondary crushing stage (Gokce etal., 2011; Nagataki etal., 2004). Furthermore, more crushing stages would yield products with decreasing particle sizes, which contradicts the mainstream use of RA (i.e. coarser RA fractions are preferred, regardless of the application). These factors should be taken into account when producing RA as, from an economical and environmental point of view, it means that relatively good quality materials can be produced with lower energy consumption and with a higher proportion of coarse aggregates, if the number of crushing stages is prudently reduced.
1200t/h aggregate jaw crusher for sale - ftm machinery
Aggregate is a kind of loose granular material which plays an essential role as the skeleton and backbone in concrete. Aggregate is divided into coarse aggregate, fine aggregate, and coarse aggregate. While the aggregate can be included the pebbles, gravel, waste slag and so on. Fine aggregate mainly means the medium and fine sand. When concrete is mixed, cement is mixed with water to form dilute paste.
If the aggregate is not added, it will not be formed and will not be able to be used. Therefore, aggregate is a very important raw material in architecture. The total volume of coarse and fine aggregate accounts for about 70% of the concrete volume, so the performance of the aggregate has a great influence on the performance of the prepared concrete.
The aggregate with particle size less than 4.75 mm is called fine aggregate, commonly known as sand. Sand is divided into natural sand and artificial sand according to the source of production. Natural sand is formed by natural weathering, flow transport, separation and accumulation, with a particle size of less than 4.75 mm, but excluding soft rock and weathered rock particles. Natural sand includes river sand, lake sand, mountain sand, and desalinated sea sand. Artificial sand is collectively called for mechanical sand and mixed sand dealt by soil removal.
Sand aggregate plays a very important role in concrete. It acts as the skeleton of foundation, transferring pressure and compression. Even if there is no cement paste, it can support the load. Sand is mainly to fill the gap of stone, increase its density, at the same time restrain shrinkage and prevent cracking. The good concrete sand aggregate should satisfy the angle, the grain shape is appearing three-dimensional, so that each material in the concrete can bite each other, increase the building strength, improve the construction quality, so what is the excellent aggregate crushing equipment?
The aggregate crushing equipment can also be roughly divided into two types according to the difference in particle size between the coarse and fine aggregate. One of them is a jaw crusher, which can break up the bulk material into stones of various sizes that we need.
Jaw crusher plantsare popular among customers. Jaw crusher is the early crushing equipment, because of its simple and solid structure, reliable work, easy maintenance and low production and construction, the jaw crusher now is still widely used in metallurgy, chemicals, building materials, electricity, transportation and other industrial sectors.
It is used for coarse, medium and fine crushing of various ores and rocks with a compressive strength of 147-245 MPa. FTM Machinery manufactured fixed jaw crushers and portable jaw crushers with different specifications, and their sizes are different. If you want to buy jaw crusher, please leave your message on our website and our manager will send you the latest quotation.
When the jaw crusher is working, the movable jaws periodically reciprocate the fixed jaws, moving up and down. When approaching, the material is crushed by crushing, splitting, and impact between the two jaws. When leaving, the broken material is discharged from the discharge port by gravity.
1.The overall plan is reasonable and the equipment output is up to standard. The whole jaw crusher plant adopts the combination of jaw crusher, cone crusher, vibrating screen, feeder and conveyor to ensure the production requirements and the grain size. After the project is completed, the production scale has reached an annual output of 5.4 million tons.
2.Excellent product size and high crushing efficiency. The project uses a cone machine as the secondary crusher. FTM Machinerys cone crusher has been improved a lot, with the advantages of large capacity, low energy consumption, uniform force, good sealing and clear cavity.
3.3Environmentally friendly production lines. The pollution problems generated by the project throughout the production process are within control. Air pollution waste emissions are well below the national 30mg/m3, which is designed and implemented in strict accordance with national environmental emission standards.
1.The main contents include checking and repairing the adjustment device, adjusting the drain gap, adjusting the head-on or replacement of worn liners. Check the transmission part, lubrication system or replace lubricants in a timely manner, etc. The minor repair cycle is about 1~3 months.
concrete crusher,concrete aggregate crusher machine-dsmac
Main devices of the gravel aggregate production line: Primary crushing--jaw crusher, secondary crushing--impact crusher and cone crusher, then sand making machine, and finally flour mill. Aggregate plays a very important role in construction industry. For example, without aggregate, cement cannot be shaped in the process of stirring. Thus, it is a kind of indispensable construction material widely used in those areas of construction, road building, and rail building and so on.
The proven PE series jaw crusher is designed to crush efficiently all, even hardest rock and recycle materials. DSMAC jaw crusher is designed for long life service with minimum maintenance for hard, tough, abrasive material and overload high capacity.
Robust and Assembly Design
The Right Cavity Design
Designed to Bring Your Crushing Costs Down
Little Dust and Low Noise Level
PF series impact crushers feature a unique combination of heavy-duty rotor, wear material and crushing chamber design. This combination has proved revolutionary in improving capacity, product quality and in reducing operating and wear costs, ensuring the lowest operating cost per tonne, for a wide range of materials and applications.
Easy blow bars locking device;
Wide choice of blow bars and liners;
Friendly design to easy maintenance;
Many options to improve crusher efficiency;
Safe environment working condition.
Cone crusher is widely used in metal mine, metallurgical, chemistry, construction, cement, sand and stone production industry. It applies to the primary and secondary crushing of various of mines and rocks, the Protodyakonov hardness of which is f=5-16, such as iron ore, nonferrous ore, granite, limestone, quartzite ore, sandstone, pebble and so on. DSMAC have many kinds of cone crusher ,they all enjoy a worldwide reputation as rugged, durable, easy to maintain, reliable and so on.
Aggregates production and mines;
Secondary, tertiary and fine crushing stages;
Stationary and mobile applications.
Easy Adjustment for Production Requirement
Rotor centrifugal crusher (type RSMX) is a high-performance vertical-shaft crusher equipped with vertical shaft and imported originally from Germany, which specializes in crushing materials and shaping cube. With adopting the rock-on-rock principle, every material particle can be acted by an external force and the cube shape of crushed material is improved.
The material is not easily blocked;
The rotor is composed by detachable parts;
The steel structure foundation bed adopts the welding structure
Rotor centrifugal crusher without air circulation system reduces the height of the machine and makes the equipment more safe and stable
mobile aggregate concrete crusher plant for sale - best stone crusher plant solution from henan dewo
Dewo machinery can provides complete set of crushing and screening line, including Hydraulic Cone Crusher, Jaw Crusher, Impact Crusher, Vertical Shaft Impact Crusher (Sand Making Machine), fixed and movable rock crushing line, but also provides turnkey project for cement production line, ore beneficiation production line and drying production line. Dewo Machinery can provide high quality products, as well as customized optimized technical proposal and one station after- sales service.
CONSTMACH is the leader concrete batching plant, crusher and concrete block machine manufacturer of Turkey since its foundation, 2002. Cement silos, sand screening and washing plants, mobile crusher are other product types which are manufactured by CONSTMACH.
Tracked Jaw Crusher Plant Track mounted mobile jaw crushing plant (Crawler type mobile jaw crusher station) can be used for the mobile operation of stone crushing in highways, railways, hydropower projects, etc. It has features of unique structure, light weight, reliable operation and high output and is a preferred equipment for the cr
Browse our inventory of new and used EAGLE CRUSHER Crusher Aggregate Equipment For Sale near you at MachineryTrader.com. Models include ULTRAMAX, 1400, 1200, 3242, JUMBO, 15x36, 18x36, 20x36, 32X15, and 1000.
It consists of JS500 compulsory concrete mixer, automatic control system, cement silo, feeding system and PLD series aggregate batcher.It has simple structure, which is easy to disassemble. In addition, it can produce even concrete at short time, which is very suitable for small scale construction site, casting factory, small concrete ...
how to use glass aggregate in concrete - terrazzco
Concrete typically consists of sand (fine aggregates) and different sizes of stones and gravel. But what about glass aggregates? There is now interest in the use of substitute materials in concrete, with glass options recommended for recycled material use.
Glass aggregates can even benefit workability and the durability of the concrete finish. Furthermore, glass aggregates are used more often today largely due to their color options. They can add unique colors to the floor finish or even add a highly polished shine. Well examine how glass is used in applications such as flooring and countertops, and recommend some of the best colors to consider.
It is important for contractors to use clean glass in concrete to prevent issues related to an alkali-silica reaction between the cement and glass aggregates. Many of todays glass aggregates come from post-industrial sources, which are crushed and cleaned for use in indoor applications such as terrazzo and concrete floors, and concrete countertops. The benefits of using glass in concrete include its color options and its green value to a concrete surface.
Because glass chips are recycled, there is no extraction to retrieve the material and reduces landfill spaces. Finding green materials to work with is essential in todays construction landscape. and the use of recycled glass contributes to LEED points as well.
Glass is graded by size. Glass aggregates can be crushed up to several inches or as small as fine powders, and are not sharp to handle. To reveal the glass aggregates in either a terrazzo or concrete floor, polishing and grinding techniques are employed. Contractors can also use exposed aggregate techniques, or broadcast the glass across the surface and expose it afterward.
In regards to color options, glass is appealing to contractors because of its wide range. Glass aggregates provide color options that cant be found among gravel or marble chips. You can find colors that range from brown, blue, green, red, and yellow; however, some colors are produced far less than others (red and orange glass) and are priced higher.
When it comes down to composition, a contractor can mix glass with concrete in any way they like. They can pair light glass colors with a dark matrix, dark glass colors with a light matrix, or even match the same glass color to the matrix.
There are also clear glass options, which take on the color of the matrix. This gives the terrazzo or concrete floor depth, and options for clients that require a durable flooring option system but dont want the exposed aggregates to stand out.
In place of sand, contractors can use fine glass aggregates instead. Studies have shown that glass powder increases the workability, decreasing the time, cost, and energy to install the concrete surface while gaining a highly polished surface with greater strengths.
There are ongoing studies on the effects of glass aggregates use in concrete. When using glass aggregates for outdoor concrete applications, alkali-silica reactions should be evaluated. Outdoor applications or areas where concrete is exposed to moisture are commonplace for this reaction to occur. The silica in the glass and the alkali in cement forms a gel that swells when moisture is present. As a result, this can cause cracks to form.
Can alkali-silica reactions be prevented? The answer is yes. Solutions to the issues include either using metakaolin to suppress the reaction, or grinding the glass finely to pass smaller screens. Another recommended solution is to address the moisture, and sometimes a good sealer can help suppress the reaction as well.
Concord Terrazzo Company crushes post-industrial and post-consumer recycled aggregates with a cone or jaw crusher, cleaned and processed, and packaged for contractors to purchase for terrazzo or concrete applications. For concrete applications, glass aggregate is commonly in countertops but can be used for floors, walls, and other decorative designs. Another solution is to review epoxy terrazzo flooring and countertops, which go hand in hand with glass aggregates for any indoor environment to produce a durable, beautiful, and low maintenance surface.
recycled concrete aggregate and fly ash produce concrete without portland cement - sciencedirect
It has been shown that concrete can be produced entirely from waste products such as recycled concrete aggregates and fly ash. The recycled concrete gains strength very slowly probably due to pozzolanic reaction between fly ash and calcium hydroxide from the cement paste in the old concrete. It is suggested that the process may be used to upgrade the quality of demolished and crushed concrete for fill or road base purposes.
aggregate crushing plant-high safety high efficiency stable performance
As a result of the great development of the basic construction and the reconstruction of the towns and the rapid rise of the high-rise buildings, the old-style buildings die out, and the waste of the construction wastes is directly buried without treatment, Then it will cause long-lasting harm to our living environment. Crusher plant can deal with construction wastes well.
Our company, a professional construction machinery manufacturer in China, provides top quality crushing plant, asphalt plant, concrete batching plant for sale. If you are interested, just contact with us now!
Compared with the mobile crushing plant, the stationary crushing screen plant has no tires. In view of the present situation of construction waste treatment in our country, crushing plant has strong advantages, but with the increasing maturity of construction waste disposal market, it will slowly be transformed into fixed crushing plant, that is to say, mobile crushing station is transitional equipment, and slowly will be converted into fixed type.
It is mainly used for fields like metallurgical, chemical, building material, hydro-power that needs material processing, especially for highway, railway, hydro-power with the operation of mobile stone. Customers can choose multiple configuration according to types of raw material, size and finished material requirements.
Mobile crusher plant can not only reduce the cost of transportation, but also cooperate with brick making machine to make the raw material into finished products at one time. With the increasing market demand, various types of crushing plant are needed, such as jaw mobile crushing plant, tire mobile crushing plant and other types. These plants can produce product with high quality, high crushing ratio, reliable performance.
Vibration feeder takes eccentric shaft as excitation source, gear transmission, low noise, stable operation, long life, and it can screen fine material in advance to make crusher more efficient. Adjust the gap grid design to prevent material blockage. Customers can selectively install speed-regulating motor, easy to control the feed quantity, no need for frequent start-up of the motor.
Circular vibrating screen is a kind of screening machine, which mainly produces centrifugal inertia force (excitation force) with radial variation because of the unbalanced rotation of the vibrating wheel of the exciter. Itdrives the screen box and makes the screen vibrate. The trajectory of the screen frame is elliptical. The material on the screen is thrown up by the upward movement of the screen surface, and then falls back to the screen surface after a distance. In this way, the screening is completed in the process of moving from the feed end to the discharge end. The amplitude of the vibrating screen can be adjusted by changing the weight and position of the counterweight.
As far as the counterattack crusher is concerned, the rotor rotates at high speed under the drive of the motor while working, and the material entered from the feed port is hit by the plate hammer on the rotor, which is broken by the high speed impact of the plate hammer; the broken material is hit back on the liner and broken again; later, it is discharged from the outlet. Adjusting the gap between counterattack frame and rotor frame can change the particle size and shape of material.
The material is uniformly transported into the crusher through the feeder, and after the crusher is initially broken, the closed circuit system is formed by the circular vibrating screen to realize the cyclic crushing of the material, and the material in accordance with the grain size requirements is output by the conveyor, so as to achieve the production purpose.
Before the operation, check whether the supporting equipment can run normally, such as crusher, feeder, and so on, whether the connection of these supporting equipment is loose or falling off, and whether the transmission device is abnormal. Especially the crusher, ensure that there is no residual materials in the crusher. In addition, because the working environment of the stone crushing plant is complex, the tire of the mobile crushing station is a vulnerable part, the user should also check whether the tires can work normally before carrying out the operation, so as to ensure the overall performance and normal operation.
The circuit problem of the whole machine in the operation process is a problem that the user needs to pay attention to. If there are special noises, odors or sparks in the working process, stop the operation immediately, maintain in time and never work by force. Otherwise, the whole equipment and motor may be damaged, and it is easy to cause inestimable losses to the user.
Before the stop of the crushing plant, the user must ensure that all the equipment can stop after all the materials are discharged. After the mobile crusher stops, the user should also check the circuit of the equipment, the supporting equipment and lubrication in time. For any abnormal condition, repair and maintain in time. In addition, due to the complexity of the working environment of the aggregate crushing plant, users need to clean and maintain the equipment in time after operation.