clay production rotary kiln

rotary kilns

rotary kilns

FEECO is a leading manufacturer of highly engineered, custom rotary kilns for processing solids. Our high temperature kilns have earned a reputation for their durability, efficiency, and longevity. We offer both direct- and indirect-fired units.

Rotary kilns work by processing material in a rotating drum at high temperatures for a specified retention time to cause a physical change or chemical reaction in the material being processed. The kiln is set at a slight slope to assist in moving material through the drum.

Direct-fired kilns utilize direct contact between the material and process gas to efficiently process the material. Combustion can occur in a combustion chamber to avoid direct flame radiation, or the flame can be directed down the length of the kiln.

All FEECO equipment and process systems can be outfitted with the latest in automation controls from Rockwell Automation. The unique combination of proprietary Rockwell Automation controls and software, combined with our extensive experience in process design and enhancements with hundreds of materials provides an unparalleled experience for customers seeking innovative process solutions and equipment.

Indirect-fired kilns are used for various processing applications, such as when processing must occur in an inert environment, when working with finely divided solids, or when the processing environment must be tightly controlled.

Calcination refers to the process of heating a material to a temperature that will cause chemical dissociation (chemical separation). This process is used frequently in the creation of inorganic materials, for example, the dissociation of calcium carbonate to create calcium oxide and carbon dioxide.

Thermal desorption is also a separation process. This process uses heat to drive off a volatile component, such as a pesticide, from an inorganic mineral, such as sand. The component is vaporized at the increased temperature, causing a separation without combustion. In some cases, an indirect rotary kiln would be best for this application, because the volatile chemicals may be combustible. The indirect kiln will supply the heat for desorption, without the material coming into direct contact with the flame.

Organic combustion refers to the treatment of organic wastes with the intent of reducing mass and volume. Organic waste is treated in the kiln, leaving behind an ash with considerably less mass and volume. This allows for more efficient and effective deposit of waste materials into landfills.

Sintering is the process of heating a raw material to the point just before melting. This increases the strength of the material, and is commonly used in the proppant industry, where sand or ceramic materials are made stronger.

Heat setting involves bonding a heat resistant core mineral with another, less heat resistant coating material. Unlike an unheated coating process, here, a rotary kiln heats the coating material to just below liquefaction point, allowing it to coat the heat resistant core more evenly and more securely. This process is commonly seen in the manufacture of roofing granules, where a mineral such as granite is coated with a colored pigment, producing a product that is both durable and aesthetically pleasing.

Reduction roasting is the removal of oxygen from a component of an ore usually by using carbon monoxide (CO). The CO is typically supplied by mixing a carbonaceous material such as coal or coke with the ore or by feeding it separately. Examples are the reduction roasting of a hematite containing material to produce magnetite that can be magnetically separated. In the Waelz process, zinc oxide in steel mill wastes is reduced to metallic zinc and volatilized for recovery in the off-gas system.

Thermal Desorption for Spent CatalystsRotary Kiln3D Indirect Kiln for Activated CarbonPyrolysis Kiln Seal3D FEECO Pyrolysis KilnPyrolysis KilnWorn Rotary Kiln RefractoryKiln Alignment SoftwareBatch Rotary Kiln TestingProcessing Challenges When Working with Rotary KilnsFEECO Batch Kiln BrochureIndustry Focus COVID-19 Demands Medical Waste Incineration CapacityIndirect Fired Rotary Kiln ReplacementRotary Kiln IncineratorsResource of the Week: Thermal Testing with Kilns3D Model of a FEECO Carbon Activation KilnRotary Kiln Testing ThumbnailRotary Kiln TestingIndirect Batch Rotary Kiln Testing, Batch Calciner Testing, Thermal Process DevelopmentKnowing When its Time to Replace Your Rotary Drum Seal, Leaf SealRotary Drum Drive ComponentsRotary Drum BreechingReplacement Rotary Drum BearingsBoomin Catalyst Market Drives Demand for Rotary Kiln Repair Services, Rotary KilnsReplacement Dryer (Drier) and Kiln BurnersCombustion ChambersReplacement Rotary Drum ShellRotary Drum Laser Alignment Process, Rotary Drum AlignmentWhy Post Maintenance Alignment is Critical to Rotary DrumsCauses of Tire (Tyre) and Trunnion Wear, Rotary Drum TireFEECO Tire (Tyre) Grinding Machine, Tire and Trunnion Grinding in ProgressRotary Drum Tire (Tyre) Wear Pattern from Excessive Wheel Skewing, Rotary Drum Tire in Need of Tire GrindingRotary Drum Tire (Tyre) Wear Pattern from Poor Housekeeping Practices, Rotary Drum Tire in Need of Tire GrindingRotary Drum Tire (Tyre) Wear Pattern from Misalignment, Rotary Drum Tire in Need of Tire GrindingRotary Drum Tire (Tyre) Wear Pattern from Using Improper Tire Lubricant, Rotary Drum Tire in Need of Tire GrindingTire (Tyre) and Trunnion Wheel GrindingTire (Tyre) and Trunnion GrindingIndirect Rotary Kiln (Calciner) for Plastics PyrolysisPlastic to Fuel Conversion via Pyrolysis Replacement Rotary Drum PartsRotary Drum Thrust RollersRotary Drum Trunnion Wheels (Rollers)Rotary Drum Riding Ring (Tire/Tyre)Resource of the Week: Girth Gears PageRotary Kiln System Optimization, Rotary Kiln Process AuditSpring-Mounted Replacement Rotary Drum Girth GearRotary Kiln Gains Traction as E-Waste Crisis Looms, Metal Recovery from E-WasteIndirect Batch Rotary Kiln Testing, Batch Calciner Testing, Thermal Process Development, Metal RecoveryDirect-Fired Rotary KilnRotary Kiln Chain and Sprocket Drive AssemblyRotary Kiln Gear and Pinion Drive AssemblyRotary Kiln Friction Drive AssemblyRotary Kiln Direct Drive AssemblyRotary Kiln Trunnion BaseRotary kiln end dam for increasing loading, retention time, and bed depthResource of the Week: Rotary Kiln Customization Slideshare PresentationKaolin Clay CalcinationLithium-ion Battery Recycling OpportunitiesRotary Kilns in Expanded Clay Aggregate ProductionBatch Kiln for Testing Expanded Clay AggregatesRotary Kiln Refractory Failure Illustration, Rotary Kiln Shell Hot SpotRotary Kiln Refractory InspectionDirect-Fired Rotary Kiln for SpodumeneCalciner (Indirect Kiln) for Lithium Recovery from SpodumeneRotary Kiln Complete SystemFEECO Batch Kiln for Testing CalcinationRotary Drum Drive BaseRotary Kilns for Advanced Thermal Processing in SustainabilityResource of the Week: Project Profile on a Rotary Kiln (Calciner) Resource Recovery SystemResource of the Week: Tire Grinding BrochureResource of the Week: Slideshare Presentation on Rotary Kiln Sizing and DesignResource of the Week: Unitized Drive Base BrochureDiagram Showing a Rotary Kiln with Co-current AirflowDiagram Showing a Rotary Kiln with Counter Current AirflowDiagram Showing Co-current Airflow View All >

The advantages to a FEECO rotary kiln are that it is built to the highest quality standards and is backed by over 60 years of process design experience. The FEECO Innovation Center offers batch and pilot scale kilns that can simulate conditions in continuous commercial rotary kilns, allowing our customers to test small samples of material under various process conditions, as well as part of a continuous process. With options in both co-current and counter-current flow, and direct or indirect configurations, the FEECO test kilns offer a variety of options to suit your thermal testing needs. We also offer support equipment such as a combustion chamber, afterburner, baghouse, and wet scrubber for testing.

lightweight expanded clay aggregate (leca) production line | fote machinery

lightweight expanded clay aggregate (leca) production line | fote machinery

Definition: light expanded clay aggregate or expanded clay aggregate (LECA or ECA), also called ceramic pellet, is one of the most popular lightweight aggregate made by sintering clay in a rotary kiln to about 1200C.

Current lightweight expanded clay aggregate market data shows that the market of LECA has shifted its direction from traditional construction engineering to craft products and horticultural maintenance.

The production materials of traditional materials such as clay and shale have been replaced by industrial waste residue and silt and the development trend of machinery has evolved into a large scale and automation.

In the following future, while focusing on economic development, the LECA suppliers should pay attention to reduce pollution and resource waste to ensure the rapid and stable development of production lines.

There are usually two types of LECA manufacturing techniques: sintering and sintering-expanded. The difference between them is in the process of sintering-expanded, the aggregate expands by a larger volume.

Jaw crusher is the primary machine which is used for coarse, medium and fine crushing of various ores and rocks with a comprehensive strength between 147 and 245 MPa, and processes them into small pieces of 10-350 mm.

Advantages: In recent years, FTM has specially developed a powerful jaw crusher to meet the needs of crushing high-strength and high-hardness micro-carbon ferrochrome in metallurgical, mining, construction and other industrial sectors.

The ball mill is the key equipment for grinding the material after crushing. Ball mill is widely used in the production of cement, silicate products, new building materials, refractory materials, fertilizers, black and non-ferrous metal dressings and glass ceramics, dry or wet grinding of various ores and other grindable materials.

The granulation disc adopts an overall circular arc structure, and the granulation rate can reach 93% or more. The granulation tray has three discharge ports, which facilitate intermittent production operations, greatly reducing labor intensity and improving labor efficiency.

The dryer is mainly used for drying certain moisture or particle size materials of mineral processing, building materials, metallurgy and chemical industry, and the equipment operation is simple and reliable.

Advantages: The equipment has an application range and it also can be customized. It has low noise, high efficiency and environmental protection, advanced lubrication system, long service life, small installation inclination angle and good screening effect.

The single-cylinder cooler is one of the important equipment in the rotary kiln system. The clinker from the rotary kiln (1000-1200 C) is fully exchanged with the air through the cylinder rotating belt to cool the material to below 200 C, at the same time improve clinker quality and grindability.

Fote Mining Machinery (FTM) located in Henan is one of the most famous mining machinery suppliers, which is committed to manufacturing mining machines of green building materials, and provides intelligent mining products and advanced solutions.

FTM is a professional supplier of lightweight expanded clay aggregate machinery and equipment, and all the equipment has high quality and significant advantages, and the prices are also very reasonable.

In a word, Fote Mining Machinery is a good choice for LECA suppliers to choose lightweight expanded clay aggregate machinery manufacturers. Welcome to consult us if you have any requirements about the LECA production line.

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.

production stalite

production stalite

STALITE's strong end-use products begin with the production processing of our raw material slate. Slate possesses the high strength and lasting durability necessary to create a superior lightweight aggregate. Unlike shale or clay deposits formed from mineral or organic sediments, the slate used in STALITE was formed from volcanic ash. This volcanic ejecta, free of impurities which were burned away at very high temperatures, was deposited in a wet environment and compressed under extreme pressures for millions of years.

The resulting material is an extraordinary slate deposit whose unique properties contribute to making STALITE the very finest high performance lightweight aggregate in the world. In the foothills of NC, east of Charlotte, NC is the only known source of slate that is being used as a raw material for rotary kiln expanded slate lightweight aggregate

Several types of raw material can be expanded in a rotary kiln to produce structural lightweight aggregates. These materials can be classified as clays, shales and slates. The primary difference in these three classifications of materials is their strength, density and absorption. Clays and shales are naturally softer, and less dense than slate. After processing in a rotary kiln, clays and shales have 24-hour absorptions ranging between 15% and 30% (compared to 6% for STALITE). During mixing or pumping concrete, clay and shale absorptions can be as high as 50% (compared to 9% for STALITE). Due to the higher material strength of STALITE slate aggregate, higher strength concretes can be achieved with lower cement contents allowing for more economical concrete mixes. BEGIN STRONGER = END STRONGER.

The raw material mined by STALITE is an argillite slate located in a geological area known as the Tillery Formation. It is a thinly laminated, gray, fine-grained siltstone, composed of clastic (transported) rock fragments. The Tillery Formation is a complex system that must be selectively mined in order to separate the desirable product from the non-desirable to manufacture a high quality expanded slate aggregate.

The geologic history of the Tillery Formation began 550 million years ago in the Cambrian Period, approximately 330 million years before dinosaurs. Rock fragments of volcanic ash origin were deposited in a water environment (sedimentation) and later solidified into solid rock (lithification). Consequent burial and tectonic pressure then changed (metamorphosed) the rock into argillite slate. Along with the deposition of the volcanic ash was an occasional ash (debris) flow or gravitational mud-type flow into the same deposition basin. Additional layers, consisting of volcanic tuff with high calcite concentrations, formed within the system. Subsequent millions of years of geologic forces caused the alternating layers of material to fold and fault, causing disorder to the once ordered, layered system. Along with this disorder came diabase dike rock intrusions of Triassic-Jurassic age (about 180-220 million years ago), which caused additional rock structures of vertical emplacement that further complicated the system.

The calcareous tuff impedes the bloating process of lightweight aggregate production. At 2,000 degrees F (1,000 degrees C), the calcite simply calcines. At high temperatures of over 2,200 degrees F (1,200 degrees C),diabase rock (specific gravity of 3.0) melts to a glassy type of rock with no specific gravity change. Because this high specific gravity creates havoc on a desired lightweight specific gravity material, it should be avoided totally. The only way to avoid this material is through a process of selective mining. Extensive core drilling must be performed along with microscopic, chemical, and laboratory test bloating of the core in order to map the subsurface material and identify desirable versus non-desirable aggregate. Computer software must then be used to identify high-quality cross-sections of desirable versus non-desirable rock zones. Mining computer software can then be used to design the selective mining sequence. A modern fractionation plant with controllable radial stackers and feed systems then crushes the high-quality bloatable material to optimum size for processing and separates it to be conveyed to the raw feed storage silo.

STALITEuses a 3-D mapping process as a guide for selective mining of the slate that is best suited for the production of STALITE. The quarrys location allows the raw slate to be efficiently conveyed directly to the rotary kilns.STALITEhas confirmed reserves of raw material to supply our needs throughout the 21st century.

After blasting, pit loaders are used to load the blasted rocks into haul trucks. Haul trucks move the rocks from the pit to the primary crusher at the processing plant. The primary crusher breaks the large rocks from the pit into smaller pieces. The primary crusher can crush between 300 and 2,000 tons per hour. As the rocks pass through the crushers, they are moved around the processing plant on conveyor belts.

After crushing, rocks are broken down to smaller sizes and go through a screening process. By using various size screens, the crushed rock can be separated by size. Some screens are larger and they allow the bigger rocks to pass through. STALITEs process requires rocks be crushed and screened several times before they are put in a stockpile with other rocks the same size.

After being crushed to an optimum size for processing, the raw slate is fed into STALITE'spatented pre-heater. The pre-heater conditions the rock before entering the rotary kiln. The pre-heater slowly heats the rock as it comes down to the kiln. The kiln is fueled by coal that is pulverized and blown into the kiln. In the kiln, the slate is heated to approximately 2,200 degrees Fahrenheit. As the slate approaches this temperature it becomes almost molten, like lava. In this molten state, the rock is plastic enough to allow gases to evolve, forming small, unconnected voids uniformly throughout its mass. The expanded rock then falls to the cooler, where it is air-cooled. When the expanded slate is cooled, the cells remain allowing for its low unit weight.

Expanded slate aggregate is produced by the rotary kiln method. This discussion describes one specific lightweight aggregate manufacturing plant. Other rotary kiln process facilities are similar, but may have variations from the process described herein.

The rotary kiln is a long tube that rotates on large bearings. The kiln is lined with insulation and refractory materials. Raw slate is fed from the storage silos into patented pre-heaters that allow the rock to heat up at a moderate rate. It then enters the upper end of the kiln where it slowly revolves and moves toward the burn zone near the lower end of the kiln. The burn zone reaches temperatures in excess of 2,200 degrees F (1,200 degrees C).

STALITE uses high BTU, low sulfur coal and natural gas for its heat sources. Some lightweight aggregate production facilities use only natural gas, while others supplement these traditional energy sources by burning hazardous wastes. In the burn zone of the rotary kiln, the slate becomes sufficiently plastic to allow expanding gases to form masses of small, unconnected cells. As the expanded slate cools, these cells remain, giving the aggregate its low unit weight and low absorption. The expanded material, called clinker at this point, leaves the lower end of the kiln and enters a forced-air cooling system. This cooling process reduces the chance that the aggregate will crystallize as can happen in water-cooled systems where the very hot expanded material is dropped directly into a pit filled with cold water.

From the cooler, the clinker is conveyed to a classification area. Here the material is crushed and screened to various size fractions. These different size fractions are kept separate until, by means of an automatically controlled blending system, specified gradations are produced for various applications. After blending, actual moisture content is automatically adjusted to a predetermined level.

The expanded slate aggregate is then tested for proper gradation, moisture content, specific gravity and unit weight. After testing is completed, the expanded slate aggregate is stored or conveyed directly to trucks or railcars for shipment.

Prior to loading, trucks and railcars must be inspected for cleanliness and washed when needed. A particular procedure is carefully followed when loading material from either the storage silos or the stockpiles to ensure that material consistency is maintained. A rigid quality control and testing program confirms compliance with the customer's specified needs.

The cooled, expanded slate is conveyed to the classification area. There it is crushed and screened into different size fractions. After crushing, the different size fractions are stored in separate silos until they are blended into standard or custom gradation blends.

Environmentally Conscious STALITE uses high BTU, low sulfur coal for its heat source.Fly ash and STALITE pozzolan are collected in high efficiency bag houses supplied by the StaClean Corporation.STALITE uses lime slurry misting and caustic systems to constantly scrub CO2 and other gases out of our air streams.

These products are sold and recycled to concrete product companies as supplemental cementitious materials. STALITE uses state-of-the-art Controlled Emissions Monitors (CEM) and is continuously monitored by the North Carolina Department of Environmental Quality.

china top brick making machine manufacturer, brick block making machine & tunnel kiln supplies, custom service

china top brick making machine manufacturer, brick block making machine & tunnel kiln supplies, custom service

Our company's products include raw material feeding, mixing, crushing systems, hard plastic and semi-hard plastic extruders, automatic brick cutting and transportation equipment, tunnel kilns , rotary kilns and so on.

As a brick making machine manufacturer, Zhengzhou Yingfeng Machinery Co., Ltd. has been taking the lead in all types of rick block making machine, tunnel kiln. We are dedicated to the overall solution of large-scale production line of new energy-saving and environmentally friendly wall materials and the integration of high-end building resources.

Our company has a professional team for scientific research, technology developmentand construction . Our imported production equipment from Europe and the United States, robot automatic welding equipment, can create high-quality, high-precision, and beautiful sintered brick equipment. Our machine quality can be comparable to European and American suppliers.

d-pozzolan calcined clay technology: the only one approved in the worlds largest calcined clay production plant - dynamis

d-pozzolan calcined clay technology: the only one approved in the worlds largest calcined clay production plant - dynamis

IIn April 2019, the Cementos Argos new calcined clay production plant started its operation. Located at the Rioclaro site, in Colombia, this line was designed following the D-Pozzolan technology, which involves several patents of Dynamis. Other than the pyroprocessing, the most visible part of the plant, Dynamis took part of the entire project development activities, in close partnership with Argos. These activities started with initial laboratory tests, that developed into an engineering project and culminated in equipment supply and technical assistance during erection and start-up.

The most impressive point to stand out from this plant is the color changing technology. It is very interesting to see the reddish clay being fed to the dryer, changing its color inside the rotary kiln and finally leaving the cooler as grey calcined clay. This color-change technology is part of the D-Pozzolan Technology, a complete solution carefully designed by Dynamis to meet the specific needs of the clay calcination process. The grey color of the calcined clay allows high substitution rates and important reductions in the clinker to cement ratio, in the cost and also in the CO2 footprint of the cement produced.

The quarry is connected to the industrial plant by trucks. The raw clay received at the plant is processed by deagglomerators which are responsible for obtaining the ideal clay grainsizes for the D-FDryer (the Dynamis flash drying system). Inside the dryer, the solid particles are dragged by the cocurrent hot gas stream, making it possible to obtain high heat and mass transfer coefficients in a relatively small equipment and with small footprint. The preheated and dried material dragged by the gas stream is separated from the flue gases by a set of cyclones.

The hot gas for material drying comes from the kiln and is complemented by the D-HotGas, the Dynamis hot gas generator designed for 100% coal or petcoke. It is important to have the correct gas flow at the drying system to enable clay particles dragging. Furthermore, the hot gas generator complements the thermal load for material drying.

Dynamis D-Pozzolan technology, with the application of a D-Gasifier that operates with solid fuel (coal or petcoke), provides the very tight control of temperature and oxygen content throughout the kiln, which are fundamental points for obtaining thermally activated clay, for assuring its color change and for achieving the desired quality. The D-Gasifer is patented by Dynamis.

The product from the kiln is forwarded to a rotary cooler. As for the kiln and the dryer, it is important that material cooling is carried out in a controlled atmosphere so that the gray color obtained at previous stages does not reverse. Thus, the airflow for cooling is minimized. Lifters installed inside the cooler maximize the heat exchange coefficients between air and material. But the cooling process must be complemented by water. Dynamis installed water channels over the cooler promoting the formation of a water film on the shell. Thus, the low temperature of the calcined clay at cooler outlet is obtained by both the airflow inside the rotary drum and the flow of water outside the cooler shell. Finally, if any unexpected condition occurs and the calcined clay temperature exceeds the maximum set value, emergency lances spray water inside the cooler.

All these innovations applied in the largest calcined clay production plant in the world constitute Dynamis D-Pozzolan Technology, which is the result of intense search for innovation, partnerships with renowned players, intense investments, solid studies and large efforts of high-skilled engineers, prepared to solve problems and deliver results.

multitask kiln: several ideas to use your kiln during production downtime and also reduce costs - dynamis

multitask kiln: several ideas to use your kiln during production downtime and also reduce costs - dynamis

As many applications of rotary kilns are similar in terms of temperatures, pressures and flows, it is possible that the same kiln can be used for the production of different materials. For this reason, there are several cases of cement kilns that have been modified to be used on a new mission, such as lime production, ores calcining or calcined clay production.

There are numerous examples of modified cement kilns in the industry, but only a few with easily reversible modifications or that fit to a wide range of processes. This leads us to some questions: Nowadays, why use single product processing kilns? Why not produce different products according to market demands? Why not use the periods when clinker silos are full for drying cement mill additives such as slag, gypsum and clay?

We know that there are several reasons why most clinker kilns produce only this material, such as operational efficiency and modification costs, but we are convinced that it is possible to reach the production flexibility that todays market requests with low costs and high efficiency, through multitask kilns.

FLEXIBILITY: this is the biggest advantage of a multitask kiln. By having several different applications with few reversible changes in configurations or equipment, a multitask kiln can adapt its production to a specific period of the year, or to a market opportunity. In a scenario of low cement demand, such as the one we are experiencing, your clinker kiln could be used, for example, to:

Obviously not all materials can be dried, calcined or processed in a particular clinker kiln, as the flexibility of a kiln is limited by minimum and maximum allowed values of air and fuel flows and material temperatures and grain size, among other factors.

Thus, it is necessary to carry out an initial study to verify the characteristics of lines main equipment, obtain current operating parameters and determine the future ones and, finally, identify the main bottlenecks and limitations for using the clinker kiln in another process. Usually, the main limitations for kiln flexibility are:

Dynamis, with its technical team of multidisciplinary and highly experienced engineers in various industry segments, can assist you from an initial technical-financial feasibility study to the mechanical and electrical detailing of the solution, in addition to supplying all necessary equipment for kiln flexibilization. All these activities are carried out within deadlines that meet the fast market changes, always allowing a quick return to clinker production when necessary.

calcined clays are redefining the cement sector

calcined clays are redefining the cement sector

This week, Cemtech reviewed recent advances in clinker reduction technologies in its latest webinar. A top-quality line-up of leading experts saw Professor Karen Scrivener of EPFL, Joel Maia, CEO of FCT Combustion and Leo Fit, product manager of activated clays at thyssenkrupp Industrial Solutions (TKIS) outline how they see the future development of clinker reduction, from the introduction of LC3 cements to the different equipment required to calcinate clays and how to source the best clays for production.

Although Karen Scrivener began the presentations by explaining that Portland cement will still dominate cement production volumes for the foreseeable future, she described LC3 as "a breakthrough technology". While cementitious materials are not new for cement production, Professor Scrivener argued that the limited availability of slag and fly ash are directing cement producers towards the use of activated clays for lower clinker cements. "Calcined clay is the most available material in the quantities needed," she said.Kaolin clays are paramount for calcined clay productionLC3 includes the use of suitable clays such as kaolin, illite and metakaolin that can be activated to become a reactive binder when blended with gypsum, limestone and clinker. Kaolinite will be the most suitable clay to use because each layer is built up of a silica and alumina content that is disrupted when heated and becomes available to react with limestone. The ideal kaolinite content is 40-60 per cent in calcined clay cements, said Professor Scrivener.

Such clays are widely available in China, southeast Asia, Africa and the Americas. Some of these regions are where population growth is expected to grow fastest during the 21st century. Tests have already shown that while calcined clay cements have a lower early 1-2 day strength than OPC, they overtake fly ash and slag cement strengths by seven days and have higher strength than Portland cements after 28 days.

The advantages of using calcined clays for cement production are many, including activation at lower temperatures than clinker producition, typically between 600-850C, the potential to use existing rotary kilns and easy colour control. Among the disadvantages are high energy consumption to dry material when using flash calcination, sourcing suitable clays near to existing cement plant locations, and ensuring good workability of LC3 cements and concretes.

Karen Scrivener referred to trials that have seen CO2 reduction of LC3 cements reach 475kg/t compared to 520kg/t for PPC and 695kg/t with OPC manufacture. She also highlighted that LC3 could take the clinker factor down below the 2009 roadmap forecast of 73 per cent to 60 per cent and even 45 per cent. A 60 per cent clinker factor would give CO2 savings of 400Mt of CO2 per annum or 10 times the annual emissions of a country like Switzerland, she said.Europe, America and India are all looking to bring in new regulations for calcined clays. The European standards, which are used in Africa and Asia as well, will see the CEM IIC standard introduced in the next few months. The standard will allow a 50 per cent clinker factor in calcined clay cements, a major advance on the 65 per cent currently set by the EN197 CEM II standard.Karen Scrivener was joined by Professor Fernando Maritirena of UCLV in Cuba and Alberto Putin of IPIAC in Portugal for questions. IPIAC has many years of experience in using clays for brick production and has built a new plant in Cte d'Ivoire, while UCLV operated one of the first pilot plants for LC3 to make concrete blocks and houses.

Rotary kiln of flash calcination?Joel Maia, FCT Combustion, furthered the discussion by describing the two options that FCT Combustion offers as equipment solutions for the manufacture of calcined clays. He compared the choice of the flash calciner and the rotary kiln. FCT manufactures the FCT FlashCalx flash calciner and the RotaCalx rotary kiln, which gives it valuable experience of both methods of production.

Mr Maia claimed that the flash calciner offers the best temperature control, which is important for ensuring the reactivity of the calcined clay. This solution removes inert material before calcination in pregrinding, which also has the benefit of drying the raw material. Moreover, it enables the greater use of alternative fuels and reduces fuel consumption, although it has higher capex costs.

The rotary kiln requires no pregrinding before being fed to the kiln and it deals better with higher moisture contents. Its disadvantages include more limited alternative fuel usage, lower temperatures from secondary air for drying raw materials and grinding after calcination.

From raw materials to full-scale productionThe final presentation by Leo Fit of TKIS highlighted the polysius activated clay system. The German company is already building its first full-scale activated clay cement plant in west Africa and Mr Fit outlined the process that TKIS takes customers through when configuring a plant. This included a GEO service for selecting the best available clay to use in manufacture, assessment of costs, low moisture content and emissions, further lab tests for cement quality forecasting, and a third pilot-scale plant for flash activation before the technical solution and realisation of a project.

TKIS uses a 50kg/h pilot plant in Beckum for testing clay samples for calcination and it has a larger 500kg/h outside unit for larger volumes.TKIS see the advantages of a flash calcination system as reduced retention times, better temperature steering, higher temperatures without destroying kaolinite, moisture levels below 2C and no dust. The system uses a hammer mill to dry and reduce material to 2mm before being fed to the activator unit. Calcined clay, limestone, gypsum and clinker can then be sent to the ball mill for separate grinding.Ongoing research is being carried out by TKIS into lower heat consumption, use of cheaper and lower-quality alternative fuels, recuperation cooling and separate grinding.Cemtech's next live webinar is entitled 'Cement, energy and freight market updates' and will be held on Wednesday 4 November 2020 with free registration.

cement rotary kiln - rotary kiln - rotary kiln manufacturers | agico

cement rotary kiln - rotary kiln - rotary kiln manufacturers | agico

Cement rotary kilns refer to cement rotary calcining kilns (sometimes called rotary furnaces). It is a pyroprocessing device used to heat materials to high temperatures in a continuous process. The kiln body is a cylinder vessel with a certain degree of tilt to the horizontal level. Raw materials are fed into the vessel from the upper end and moved to the lower end, being stirred and mixed relying on the inclination and rotation of the kiln. The kiln burner produces a lot of heat by burning fuel. This kind of heat is usually transferred to materials through flame radiation, hot gas convection, kiln brick conduction, etc., which causes the chemical reaction between raw materials and finally forms clinker.

Rotary kilns can be divided into cement kiln, metallurgical and chemical rotary kiln, lime rotary kiln and so on. Cement rotary kilns are used for calcining cement clinker in the cement plant, which can be divided into dry cement kiln and wet cement kiln. Metallurgical and chemical rotary kilns are mainly applied in the metallurgical industry. As for the lime rotary kiln, it is the main equipment for calcining active lime and light burned dolomite used in iron and steel plants, ferroalloy plants, calcium carbide plants, and magnesium metal plants.

The cement rotary kiln is mainly composed of cylinder, supporting device, drive gear, refractory lining, catch-wheel device, kiln head sealing device, kiln tail sealing device, kiln hood, and other components. On the cylinder, there is a large gear ring fixed with a spring plate near the kiln tail, some pinions below are engaged with it, jointly forming the drive gear. In normal operation, the main drive motor will transfer power to this gear device through reducer to run rotary kiln. The raw material usually enters the rotary kiln from the upper end and move slowly to another end along with the chamber as it rotates. In this process, raw materials will be heated by high temperature and then decompose and produce chemical reactions so that their state finally changed. Under normal conditions, the heat source of indirect fired rotary kilns is supplied from the kiln burner outside the kiln. This kind of way protects the integrity of raw materials, while the heat source of the direct-fired rotary kiln is inside the kiln. Besides, the rotation speed and temperature of the cylinder are tightly controlled and changed according to different desire processes and material applications. After the calcination is completed, the clinker will be pre-cooled in the chamber and then be sent into the cooler for further cooling.

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.

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