function of roller press in cement plant

seven must-use concrete admixtures (additives)

Admixturesare added to concrete batch immediately before or during mixing concrete. Concrete admixtures can improve concrete quality, manageability, acceleration, or retardation of setting time, among other properties that could be altered to get specific results. Many, not to say all, concrete mixes today contain one or more concrete admixtures that will help your pouring process driving down cost while increasing productivity, The cost of these admixtures will vary depending on the quantity and type of admixture being used. All of this will be added to the cubic yard/meter cost of concrete.

Set retarding concrete admixtures are used to delay the chemical reaction that takes place when the concrete starts the setting process. These types of concrete admixtures are commonly used to reduce the effect of high temperatures that could produce a faster initial setting of concrete. Set retarding admixtures are used in concrete pavement construction, allowing more time for finishing concrete pavements, reducing additional costs to place a new concrete batch plant on the job site and helps eliminate cold joints in concrete. Retarders can also be used to resist cracking due to form deflection that can occur when horizontal slabs are placed in sections. Most retarders also function as water reducers and may entrain some air in concrete.

Air entrained concrete can increase the freeze-thaw durability of concrete. This type of admixture produces a more workable concrete than non-entrained concrete while reducing bleeding and segregation of fresh concrete. Improved resistance of concrete to severe frost action or freeze/thaw cycles. Other benefits from this admixture are:

The entrained air bubbles act as a physical buffer against the cracking caused by the stresses due to water volume augmentation in freezing temperatures. Air entrainers admixtures are compatible with almost all the concrete admixtures. Typically for every one percent of entrained air, compressive strength will be reduced by about five percent.

Water-reducing admixtures are chemical products that when added to concrete can create a desired slump at a lower water-cement ratio than what it is normally designed. Water-reducing admixtures are used to obtain specific concrete strength using lower cement content. Lower cement contentsresult in lower CO2 emissions and energy usage per volume of concrete produced. With this type of admixture, concrete properties are improved and help place concrete under difficult conditions. Water reducers have been used primarily in bridge decks, low-slump concrete overlays, and patching concrete. Recent advancements in admixture technology have led to the development of mid-range water reducers.

Accelerating concrete admixtures are used to increase the rate of concrete strengthdevelopmentor to reduce concrete setting time. Calcium chloride could be named as the most common accelerator component; however, it could promote corrosion activity of steel reinforcement. Nonetheless, concrete best practices, such as proper consolidation, adequate cover and proper concrete mix design could prevent these corrosion issues. Accelerating admixtures are especially useful for modifying the properties of concrete in cold weather.

Shrinkage-reducing concrete admixtures are added to concrete during initial mixing. This type of admixture could reduce early and long-term drying shrinkage. Shrinkage reducing admixtures can be used in situations where shrinkage cracking could lead to durability problems or where large numbers of shrinkage joints are undesirable for economic or technical reasons. Shrinkage reducing admixtures can, in some cases, reduce strength development both at early and later ages.

The main purpose of using superplasticizers is to produce flowing concrete with a high slump in the range of seven to nine inches to be used in heavily reinforced structures and in placements where adequate consolidation by vibration cannot be readily achieved. The other major application is the production of high-strength concreteat w/c's ranging from 0.3 to 0.4. It has been found that for most types of cement, superplasticizer improves the workability of concrete. One problem associated with using a high range water reducer in concrete is slump loss. High workability concrete containing superplasticizer can be made with a high freeze-thaw resistance, but air content must be increased relative to concrete without superplasticizer.

Corrosion-inhibiting admixtures fall into the specialty admixture category and are used to slow corrosion of reinforcing steel in concrete. Corrosion inhibitors can significantly reduce maintenance costs of reinforced concrete structures throughout a typical service life of 30 40 years. Other specialty admixtures include shrinkage-reducing admixtures and alkali-silica reactivity inhibitors. Corrosion-inhibiting admixtures have little effect on strength at later ages but may accelerate early strength development. Calcium nitrite based corrosion inhibitors do accelerate the setting times of concretes over a range of curing temperatures unless they are formulated with a set retarder to offset the accelerating effect.

roller compactor: basic principles and applications in pharmaceutical industry

Roller Compactors are used to force fine powders between two counter rotating rolls and presses the raw materials into a solid compact (flakes, sheets, strips). Roll Compacters are also called dry granulators.

Roller compactors can be divided into two categories: one is equipped with a fixed gap, the other one with a floating gap. Both consist of the three major units as explained above but differ in the way in which the smallest distance (gap) between the rolls is realized.

1.When a fixed gap is installed, the amount of powder drawn in into the compaction area between the rolls is inconsistent, which results in different forces applied to the powder bed. Like in slugging, this will cause large fluctuations in the ribbon and granulate properties.

2.In floating gap the distance between the rolls change according to the amount of powder provided. The force applied to the powder remains constant. This ensures that property fluctuations in the granules are reduced to a minimum.

1.In general, a major advantage of dry granulation over wet granulation is the absence of water or any organic solvents. Therefore, this methodology is especially attractive for drugs, which are moisture or heat sensitive.

1.One of the disadvantages of roll compaction is a phenomenon called loss of reworkability. Tablets made by roll compaction often show inferior tensile strength compared to tablets prepared by wet granulation or direct compaction. Minimum compaction force should be used, as well as a smaller particle size of starting powder.

2.A second disadvantage of roll compaction is the production of noncompacted powder. Because no liquid binder is used, high amounts of fines remain and less product yield is obtained versus wet granulation.

1.Preparation of directly compressible excipients: An ideal excipient for direct compression is a material with good flowability and compactibility. In many cases, an agglomeration is required to produce a directly compressible excipient.

2. Compaction of drugs and drug formulations: Some drugs have low and inconsistent bulk and tap densities accompanied with very fine and inconsistent particle sizes. If the material also exhibits poor flow properties and poor compactibility, roll compaction might be used to overcome the raw material difficulties.

3.Granulation of herbal dry extracts: Herbal dry extracts often possess a considerable hygroscopicity due to their hydrophilic components like sugars or organic acids. Furthermore, extracts often show poor flow and compression properties making a compaction/ granulation step necessary prior to tableting.

ready-mix concrete - cemex

It is a material that can be cast into different shapes, is durable, is the most attractive construction material in terms of compressive strength (construction material with highest strength per unit cost), and its increasing use is fundamental for sustainable construction.

CEMEX does not simply manufacture concrete, but develops solutions based on the thorough knowledge and application of concrete technology. Leveraging years of experience, a worldwide pool of knowledge, and state-of-the-art expertise about the different concrete constituents and their interaction, CEMEX offers its customers concrete by designtailor-designed concrete.

CEMEX concrete technologists are able to modify the properties of concrete through the use of innovative chemical admixtures, combined with the proper proportions of the various concrete constituents. For example, depending on the type of application and jobsite requirements, we can design concrete that is more fluid, stronger, develops strength faster, and also retains workability longer.

Through the development of chemical admixtures solutions, researchers at CEMEXs Global Center for Technology and Innovation design special concretes that fulfill the construction industrys increasingly demanding performance requirements. CEMEX offers a special concrete portfolio, comprised of such products as ultra rapid hardening concrete, crack-resistant/low shrinkage concrete, self-consolidating concrete (SCC), architectural concrete, pervious concrete, and a number of others.

We continuously work to improve the properties of concrete that make it a key component of sustainable construction: durability, resistance to aggressive environments, light reflection, and capacity to store energy, among others.

We also constantly work to develop innovative solutions that advance the sustainability of structures made with concrete. In this way, our customers can design sustainable buildings that can take advantage of the benefits of concrete in a wide range of applications.

Standard ready-mix concrete is the most common form of concrete. It is prepared for delivery at a concrete plant instead of mixed on the construction site, which guarantees the quality of the concrete.

Designed to enhance early strength development, this concrete allows fast formwork removal, accelerated construction sequencing, and rapid repair for such jobs as roads and airport runways. Typically used in low temperature (5-10C) concreting during winter, this concrete can also be used in buildings, railways, and precast applications. In addition to saving time, this concrete technology offers improved durability and acid resistance.

Concrete designed with micro or macro fibers can be used either for structural applications, where the fibers can potentially substitute for steel rebar reinforcement, or for reducing shrinkageprimarily early age shrinkage. Macro fibers can significantly increase the ductility of concrete, making it highly resistant to crack formation and propagation.

Fluid mortar or concrete simplifies the process of laying pipe and cable by surrounding the pipe or cable with a tightly packed shell that provides protection from the elements, prevents settling, and enables crews to work quickly.

Compacted in place and cured, roller-compacted concrete is a zero slump concrete with the abrasion resistance to withstand high velocity watermaking it the material of choice for spillways and other infrastructure subject to high flow conditions. It represents a competitive solution in terms of cost and durability when compared to asphalt.

SCC has very high flow; therefore, it is self-leveling, eliminating the need for vibration. Due to the superplasiticizers usedchemical admixtures that impart very high flowSCC exhibits very high compaction as a result of its low air content. Consequently, SCC can have very high strengths, exceeding 50 MPa.

Because of its unique design mix, pervious concrete is a highly porous material that allows water, particularly rainwater, to filter through, reduces flooding and heat concentration by up to 4C, and helps to prevent skidding on wet roads. This concrete is ideally used in parking lots, footpaths, and swimming pool border applications.

Additives are solid or liquid chemical substances that can be added to ready-mix concrete before or during preparation. Most commonly used additives either improve a hardened concretes durability or reduce a concretes water content in an effort to shorten setting times.

No other material rivals cements importance in the mix; its the ingredient that gives concrete its resistance. Although types II and IV are also employed, the most widely used cements are gray Portland type I and Pozzolana Portland type C-2.

During the mixing phase the different components come together to produce a uniform mass of concrete. Mixing time is registered from the moment material and water are poured into the cement mixer, and it begins rotating.

We're here to answer any questions or concerns you might have. We also appreciate any feedback you'd like to give. It's only through close relationships and an ongoing dialogue with our customers that we're able to better serve your needs.

preheater - khd international

KHD is a customer-focused engineering, equipment supplier, and service company, providing a full-line of competitive and environmentally friendly technologies to the cement industry.KHD, founded back in 1856,is a global leader in cement plant technology, equipment, and services and hence, the right partner for all your demands.

KHD is committed to continuously improving our technology and offering to customers. KHD understands the changing needs of our customers, andhas a long history of innovation. KHD was the first to introduce many industry leading products and processes, like our COMFLEX grinding system, PYRORAPID Kiln and PYROCLON Low NOxCalciner.

In order to provide the highest level of support for our customers, KHD has strategically placed sales offices in emerging markets around the world. With 750 employees worldwide, and CSCs and sales offices in growing markets, KHD customers are ensured the same high quality of service and products, regardless of location.

KHD is fully committed to understanding all of our customers and to being close to our customers through our local customer service centres. As a supplier of engineering, equipment, and plant services, KHD is a critical part of the supply chain to build new capacity and to upgrade and service existing capacity.

KHDs goal is to provide highly effective and competitive technology to our customers. This means understanding our markets, investing in research and development, providing cost effective solutions based on the concept of lifetime cost of ownership, and delivering world class performance.

Looking after the environment will be one of recurring themes throughout the next decades. KHD is committed to developing environmentally friendly products, saving natural resources, increasing the energy efficiency of our products, and reducing potentially harmful emissions.

KHDs goal is to create a world leading plant service business to support our engineering and equipment supply business. KHD recognises the cyclical nature of the industry in which we operate and has set a long term strategic goal of generating a major portion of revenues from plant services in the future.

KHDs greatest asset is its employees. KHD is truly a people business that strives to support, develop and treat its employees with respect. Our goal is to empower and motivate our employees to deliver global excellence.

In the early fifties there was a technical revolution. KHD built the first Preheater (Germany, Bomke & Bleckmann), a starting point of a new aera of reducing the heat consumption of the clinker pyro-processing system by nearly 50% at this time.

Today KHD is one of the technical leaders worldwide in this field. The raw meal processed in the kiln first passes through the preheater absorbing the heat content of the kiln and PYROCLON gases minimizing the heat consumption of the system. KHD Preheaters with modern designed cyclones produce low pressure drops and are high in separation efficiency. The resulting low waste gas temperatures lead to reduced heat losses, waste gas quantitites, CO2 emissions, dust emissions and electrical energy consumption.

cement roller press - roller press in cement plant | roller press cement mill

The cement roller press is a kind of grinding equipment applied for brittle materials, such as cement clinker, granular blast furnace slag, cement raw materials (limestone, sandstone, shale, etc.), gypsum, coal, quartz sand, iron ore, etc. It is designed according to the principle of bed grinding, the high-pressure load directly acts on the material layer through double rollers, which causes internal stress in particles and leads to cracks to achieve the purpose of grinding.

The cement roller press has a high energy utilization rate and remarkable energy-saving effect in the material grinding process. In cement plant, cement roller press is a kind of important cement equipment used for clinker grinding. It is usually combined with a cement ball mill to form a high-efficiency cement grinding system because the practice shows that the grinding process with small grinding ratio and step-by-step completion is more energy-saving than that with large one-time completion.

Cement ball mill is a main cement grinding mill with a low energy utilization rate (only 3%-5%). Compared with the grinding energy consumption, most of its energy is consumed by collision heating and noise. Therefore, we usually adopt the cement roller press to replace the fine crushing and coarse grinding role of the ball mill. This increases the output of the ball mill system by 30-50%, and 20-35% of the extruded materials are smaller than 0.08mm, 65-85% are smaller than 2mm. Besides, a large number of cracks will be produced on all extruded materials, which will greatly reduce the energy consumption of materials in the next grinding process.

Pre-grinding system: after the material is pulverized by the roller press, all or part of them with a good extrusion effect will enter the subsequent ball mill for further grinding. This system has the advantages of simple processes, less equipment, wide particle size distribution, and stable cement performance. But because the ground material is not classified, a large number of fine powders are back to the roller press, the power saving range is limited.

Combined grinding system: materials ground by cement roller press are divided into two parts by air classifier: coarse part and fine part. The fine part will enter the ball mill to be further ground into the finished product, the coarse part will return to the roller press to be ground again. Because the cement finished products are all ground by the ball mill, the finished products have wide particle size distribution and the cement performance is stable.

Semi-finishing grinding system: after ground by cement roller press, materials are divided into three parts through an air classifier: coarse, medium and fine, in which the coarse material is returned to roller press for re-grinding, the medium material is put into ball mill for further grinding, and the fine material is directly discharged as the finished cement product. Because the roller press and the ball mill are two completely independent circulation systems, they are easier to operate and control and are more energy saving.

Finish grinding system: this system only includes a cement roller press to complete the grinding of cement clinker. Materials ground by cement roller press are divided into two parts by air classifier: coarse part and fine part. The coarse part will return to the roller press to be ground again and the fine part will be discharged as the cement product.

The cement roller press is composed of two rollers that rotate synchronously in the opposite direction and a set of a hydraulic system. Its main structure includes a press roller system, transmission device, mainframe, hydraulic system, feeding device, and so on.

The two rollers of cement roller press, one is fixed and the other is movable, which are driven by a motor and a reducer to rotate at a relatively low speed. The movable roller bearing seat is connected with the hydraulic system. It can be moved along a horizontal direction to control the gap between the two rollers, while the fixed roller is installed in the inner chamber of the mainframe. When materials enter between the two rollers from above, pressure (50-300Mpa) is transferred to materials by the hydraulic system through oil cylinder, bearing seat, and rollers so that material particle size can be reduced by means of extrusion. After grinding, the fine particles less than 90m account for about 20-30%. At the same time, there are many cracks in the coarse particles. In the process of further grinding, their energy consumption can be greatly reduced.

AGICO is a professional cement plant equipment supplier in China. The cement roller press is one of our hot-sales products in the cement grinding unit. Compared with other cement mills, the roller press produced by AGICO has the following advantages:

Cement ball mill and cement roller press are both the commonly used equipment for clinker grinding. But in the actual cement production process, the roller press has more advantages in different aspects, mainly reflected in the following points:

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.

v-separators - khd international

KHD is a customer-focused engineering, equipment supplier, and service company, providing a full-line of competitive and environmentally friendly technologies to the cement industry.KHD, founded back in 1856,is a global leader in cement plant technology, equipment, and services and hence, the right partner for all your demands.

KHD is committed to continuously improving our technology and offering to customers. KHD understands the changing needs of our customers, andhas a long history of innovation. KHD was the first to introduce many industry leading products and processes, like our COMFLEX grinding system, PYRORAPID Kiln and PYROCLON Low NOxCalciner.

In order to provide the highest level of support for our customers, KHD has strategically placed sales offices in emerging markets around the world. With 750 employees worldwide, and CSCs and sales offices in growing markets, KHD customers are ensured the same high quality of service and products, regardless of location.

KHD is fully committed to understanding all of our customers and to being close to our customers through our local customer service centres. As a supplier of engineering, equipment, and plant services, KHD is a critical part of the supply chain to build new capacity and to upgrade and service existing capacity.

KHDs goal is to provide highly effective and competitive technology to our customers. This means understanding our markets, investing in research and development, providing cost effective solutions based on the concept of lifetime cost of ownership, and delivering world class performance.

Looking after the environment will be one of recurring themes throughout the next decades. KHD is committed to developing environmentally friendly products, saving natural resources, increasing the energy efficiency of our products, and reducing potentially harmful emissions.

KHDs goal is to create a world leading plant service business to support our engineering and equipment supply business. KHD recognises the cyclical nature of the industry in which we operate and has set a long term strategic goal of generating a major portion of revenues from plant services in the future.

KHDs greatest asset is its employees. KHD is truly a people business that strives to support, develop and treat its employees with respect. Our goal is to empower and motivate our employees to deliver global excellence.

Originally developed to separate fine material from a roller press circuit, the V-SEPARATOR has, however, also proved its value in tough applications with large mass flows and abrasive material of wide size range and high levels of feed moisture.

Material is fed from above to the builtin step grate. From here, the fine material is carried upwards with the air through the separating channels, the coarse material falls down over the step grate and is discharged at the bottom of the housing. The ratio of material load to separating air can be up to three times higher than with an airstream separator.

All internal parts are fixed and have straight and level surfaces, as does the housing. This ensures simple but effective protection against wear, eliminating the need for maintenance work for many years.

The V-SEPARATOR is an uncomplicated static separator without any moving parts. Since it carries out a whole range of process functions, it considerably extends the range of applications for high pressure comminution. In addition to reduced investment for machinery, the V-SEPARATOR also results in energy savings. With the rising cost of energy, this will become increasingly important.

products for cement and mining i flsmidth

FLSmidth provides sustainable productivity to the global mining and cement industries. We deliver market-leading engineering, equipment and service solutions that enable our customers to improve performance, drive down costs and reduce environmental impact. Our operations span the globe and we are close to 10,200 employees, present in more than 60 countries. In 2020, FLSmidth generated revenue of DKK 16.4 billion. MissionZero is our sustainability ambition towards zero emissions in mining and cement by 2030.

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rollers | types of roller | characteristics | engineering intro

Rollers are the construction equipmentused for the compaction of soil, gravel, sand, crushed stone layers, etc. Roller working principle is based on vibration,impact loading, kneading and by applying direct pressure on the respective layer. The four most commonly used rollers are;

Vibratory type rollers have two smooth wheels/ drums plus the vibrators. One isfixed atthe front andthe other oneis on the rear side of vibratory roller.Both wheels/drums are of the same diameter, length and also of same weight.Vibratory rollercovers the full area under wheel. To make vibratory roller more efficient, vibrators arealso fixed with smooth wheel rollers. Vibration of vibrators arrange the particlesby first disturbing even the arrangedones.On the other handweightof wheels exerts direct pressure on the layer. Vibratorsare turned off during the reversed motion of roller. Inthat time onlystatic weightdirectly actson the soil layer.

Vibration is to reduce the air voids and to cause densification of granular soils. During vibration of soil layer, rearrangement of particles occurs due to deformation of the granular soil because of oscillation of the roller in a cycle.

Sheep foot roller also namedtamping roller.Front steel drum of sheep foot roller consists of manyrectangular shapedboots of equalsizes fixed in ahexagonalpattern.Coverage area of sheep foot roller is less i.e.,about 8- 12% becauseof the boots on drums. Sheep foot roller done compaction bystatic weight and kneading of respective layer. This makes tampingrollerbetter suited for clay soils. Contact pressureof sheep foot roller varies from 1200- 7000Kpa.

Tamping foot roller consists of four wheels and on each wheel kneadingboots/feet are fixed. Tamping roller has more coverage area i.e., about 40- 50%. Contact pressure of tamping roller varies from 1400 8500KPa. It is best dedicated for fine grained soils.

Smooth wheel roller and vibratory rollers are the same. Both have the same characteristics. Only the difference in both is vibratory equipment. Smooth wheel roller has no vibrator attached with the drum. This makes smooth wheel roller best suited for rolling of weaker aggregates, proof rolling of subgrades and in compacting asphalt pavements. Compaction of clay or sand is not a good choice to done with smooth wheel roller. This is so, because there are many empty voids in clay soil and sand, which cannot be minimized without vibrators.

Pneumatic tired roller has anumber of rubber tires at the front and atthe rear end.Empty spaces left in between the two tires that make 80% coverage area under the wheels. Pneumatic roller has the ability to exert contact pressure ranges from 500 700Kpa. Pneumatic tired roller can be used for highways, construction of dams and for both fine grained and non-cohesive soils. It is also used for smoothening of finishing bitumen layer on highways, roads, streets etc.