6.3.1 Cement production process – Cement production processes can be categorized as dry, semidry, semiwet, and wet processes depending on the handling of raw material before being fed to the rotary kiln. Nowadays, almost all new plants are based on the dry process and many old wet plants are also remodeled to dry or semidry processes.
Dry cement manufacture has three fundamental stages: preparation of feedstocks, production of clinker, and preparation of cement, (1) Preparation of feedstock. This stage includes the process of siege, crushing, and prehomogenization. Typical raw materials used for cement production have 85% cayenne, 13% clay or blackboard, and under 1% each of materials such as silica, alumina, and iron ore.
These feedstocks are crushed into particles with a diameter of less than 20 mm and mixed with a prehomogenization pile, (2) Clinker production. As shown in Fig.6.6, the feedstock first enters the raw material to make a fine powder (raw feed), where 85% of the material is slightly smaller than 88 μm.
Then, the feed is transferred to the homogenizing silos to impair the material difference. After that, the meal is thrown into the precalciner tower to start the chemical change to cement. Precyclone towers intermix with raw feed and almost 1000°C of exhaust gas to recover energy, preheat feed, and initiate chemical reactions that result in cement.
Gases straight from the kiln, but in precalciner facilities, gasoline, and air are provided by a combustion vessel inside the tower and kiln. Typically, 60% of burned calciner and more than 90% calcination have been reached before the material enters the rotary kiln.
- Inside the kiln, temperatures reach approximately 1400°C to complete the process of chemical reactions and produce calcium silicates, called clinkers, with a diameter of 10–25 mm.
- The gas from the preheater tower is usually blended in a rawmill, which will help stabilize the future feedstock.
- After flowing through the rawmill, the gases are eventually released by a dust collector, which also obtains good particles when feedstuffs are milled.
The dust will then be recycled into homogenizing silos and served as part of the kiln feed. Figure 6.6, Overview of the dry cement manufacturing process. From Sikkema JK, Alleman JE, Ong SK, Wheelock TD. Mercury regulation, fate, transport, transformation, and abatement within cement manufacturing facilities: review. Sci Total Environ 2011;409:4167–78.
- 1 What is the most common method of manufacturing cement?
- 2 What are the two methods of manufacturing of cement?
- 3 What is the manufacturing process of concrete?
- 4 What is cement and how it is manufactured?
- 5 What are the two uses of cement industry?
- 6 What is concrete production equipment?
- 7 How many method of cementing are there?
Which type of production is used in cement industry?
Different minerals need to be mined in order to make cement. Limestone (containing the mineral calcite), clay, and gypsum make up most of it. The US Geological Survey notes that cement raw materials, especially limestone, are geologically widespread and (luckily) abundant.
Domestic cement production has been increasing steadily, from 66.4 million tons in 2010 to about 80.5 million tons of Portland cement in 2014 according to the U.S. Geological Survey 2015 Cement Mineral Commodity Summary, The overall value of sales of cement was about $8.9 billion, most of which was used to make an estimated $48 billion worth of concrete.
Most construction projects involve some form of concrete. There are more than twenty types of cement used to make various specialty concrete, however the most common is Portland cement. Cement manufacturing is a complex process that begins with mining and then grinding raw materials that include limestone and clay, to a fine powder, called raw meal, which is then heated to a sintering temperature as high as 1450 °C in a cement kiln.
- In this process, the chemical bonds of the raw materials are broken down and then they are recombined into new compounds.
- The result is called clinker, which are rounded nodules between 1mm and 25mm across.
- The clinker is ground to a fine powder in a cement mill and mixed with gypsum to create cement.
The powdered cement is then mixed with water and aggregates to form concrete that is used in construction. Clinker quality depends on raw material composition, which has to be closely monitored to ensure the quality of the cement. Excess free lime, for example, results in undesirable effects such as volume expansion, increased setting time or reduced strength.
Several laboratory and online systems can be employed to ensure process control in each step of the cement manufacturing process, including clinker formation. Several laboratory and online systems can be employed to ensure process control Laboratory X-Ray Fluorescence (XRF) systems are used by cement QC laboratories to determine major and minor oxides in clinker, cement and raw materials such as limestone, sand and bauxite.
Read Analysis of Clinker and Cement with Thermo Scientific ARL OPTIM’X WDXRF Sequential Spectrometer to learn why XRF is the technique of choice for elemental analysis in cement industry. Combination X-Ray Fluorescence (XRF) and X-Ray Diffraction (XRD) systems accomplish both chemical phase analysis for a more complete characterization of the sample.
Clinker phase analysis ensures consistent clinker quality. Such instrumentation can be fitted with several XRF monochromators for major oxides analysis and a compact diffraction (XRD) system which has the capability of measuring quartz in raw meal, free lime (CaO) and clinker phases as well as calcite (CaCO 3 ) in cement.
Read XRF/XRD Combined Instrumentation Can Provide Complete Quality Control of Clinker and Cement to learn more about technology that combines the advantages of both XRF and XRD together. Cross Belt Analyzers based on Prompt Gamma Neutron Activation Analysis (PGNAA) technology are installed directly on the conveyor belt to measure the entire material stream continuously and in real time to troubleshoot issues in pre-blending stockpile control and quarry management, raw mix proportioning control, and material sorting.
- Read PGNAA Improves Process and Quality Control in Cement Production to learn what makes PGNAA particularly suited for cement analysis.
- Accurate cement production also depends on belt scale systems to monitor output and inventory or regulate product loadout, as well as tramp metal detectors to protect equipment and keep the operation running smoothly.
The Cement Manufacturing Process flow chart sums up where in the process each type of technology is making a difference. NOTE: Need a Belt scale system for your bulk material handling? To help you decide which belt scale system is best for your mining operation, we’ve outlined the options in an easy-to-read belt scale system selection guide so you can decide which belt scale system is right for you. Click on the image, take a look at the chart, and see if it helps you decide.
What are the different methods of cement production?
Three Quick Tips For Manufacturing Of Cement. Manufacturing Of Cement. by any one of the two methods : (i) Dry process, and (ii) Wet process. In both these processes the three distinct operations of (a) Mixing, Ball mill (b) Burning, Rotary kiln and (c) Grinding are carried out.1.
- Dry process.
- In this process lime stone and clay are ground separately to tine powders and are then mixed together in the desired proportions.
- Water is then added to it so as to get a thick paste of which cakes are then made, dried and burnt in kilns.
- To the clinker obtained after burning, is added three to four per cent of gypsum and ground to very fine powder.
This powder is cement ready for use. This process is slow and costly. Also it is difficult to have the correct proportion of constituents and to do so is a cumbersome operation. The quality of cement is not so good as that of the one manufactured by the Wet process.
this method has, therefore, become obsolete and the Wet process of manufacturing cement, described in details below, is widely used.2. Wet process. (i) Mixing. The crushed raw materials in desired proportions are fed into ball mills (Fig.5.1). A little water to is added to it. Ball mill is a rotating steel cylinder in which there are hardened steel balls.
When the mill rotates, the steel balls pulverise the raw materials which forms into a solution with water. This liquid mixture is known as slurry. This slurry is then passed into storage tanks known as silos where their proportioning is finally adjusted to ensure the correct chemical composition.
- Composition of raw mix can be controlled better by the wet process than in dry process.
- Corrected slurry is then fed into the rotary kiln for burning.
- Cross section of a ball mill (ii) Burning.
- Corrected slurry is fed at the higher end of the inclined rotary kiln (Fig.5.2) whereas from the lower end of the kiln flame is produced by injecting pulverized coal with a blast of air.
Rotary kiln is a steel tube lined inside with free bricks. It is 90 to 120 metres long and from 2.5 to 3.5 meters in diameter. The kiln is mounted on rollers at a gradient of 1 in 25 to 1 in 30 and rotating once in every minute. Slurry on entering the furnace losses moisture and forms into small lumps or “nodules”.
- The nodules gradually roll down passing through zones of rising temperature until they reach burning zone where they are finally burnt at 1500 to 1650ºC.
- At this temperature “nodules” change to clinkers.
- Clinkers are air-cooled in another inclined tube similar to the kiln but of lesser length.
- Rotary kiln (iii) Grinding.
Grinding of the clinker is done in large tube mills which are kept cool by spraying water on them from outside. While grinding the clinker three to four per cent gypsum (Calcium sulphate) is added so as to control the setting time of cement. Finely ground cement is stored in silos from where it is drawn for packing.
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: Three Quick Tips For Manufacturing Of Cement.
What is the most common method of manufacturing cement?
Visit ShapedbyConcrete.com to learn more about how cement and concrete shape the world around us. Portland cement is the basic ingredient of concrete. Concrete is formed when portland cement creates a paste with water that binds with sand and rock to harden.
- Cement is manufactured through a closely controlled chemical combination of calcium, silicon, aluminum, iron and other ingredients.
- Common materials used to manufacture cement include limestone, shells, and chalk or marl combined with shale, clay, slate, blast furnace slag, silica sand, and iron ore.
These ingredients, when heated at high temperatures form a rock-like substance that is ground into the fine powder that we commonly think of as cement. Bricklayer Joseph Aspdin of Leeds, England first made portland cement early in the 19th century by burning powdered limestone and clay in his kitchen stove.
With this crude method, he laid the foundation for an industry that annually processes literally mountains of limestone, clay, cement rock, and other materials into a powder so fine it will pass through a sieve capable of holding water. Cement plant laboratories check each step in the manufacture of portland cement by frequent chemical and physical tests.
The labs also analyze and test the finished product to ensure that it complies with all industry specifications. The most common way to manufacture portland cement is through a dry method. The first step is to quarry the principal raw materials, mainly limestone, clay, and other materials.
- After quarrying the rock is crushed.
- This involves several stages.
- The first crushing reduces the rock to a maximum size of about 6 inches.
- The rock then goes to secondary crushers or hammer mills for reduction to about 3 inches or smaller.
- The crushed rock is combined with other ingredients such as iron ore or fly ash and ground, mixed, and fed to a cement kiln.
The cement kiln heats all the ingredients to about 2,700 degrees Fahrenheit in huge cylindrical steel rotary kilns lined with special firebrick. Kilns are frequently as much as 12 feet in diameter—large enough to accommodate an automobile and longer in many instances than the height of a 40-story building.
The large kilns are mounted with the axis inclined slightly from the horizontal. The finely ground raw material or the slurry is fed into the higher end. At the lower end is a roaring blast of flame, produced by precisely controlled burning of powdered coal, oil, alternative fuels, or gas under forced draft.
As the material moves through the kiln, certain elements are driven off in the form of gases. The remaining elements unite to form a new substance called clinker. Clinker comes out of the kiln as grey balls, about the size of marbles. Clinker is discharged red-hot from the lower end of the kiln and generally is brought down to handling temperature in various types of coolers.
The heated air from the coolers is returned to the kilns, a process that saves fuel and increases burning efficiency. After the clinker is cooled, cement plants grind it and mix it with small amounts of gypsum and limestone. Cement is so fine that 1 pound of cement contains 150 billion grains. The cement is now ready for transport to ready-mix concrete companies to be used in a variety of construction projects.
Although the dry process is the most modern and popular way to manufacture cement, some kilns in the United States use a wet process. The two processes are essentially alike except in the wet process, the raw materials are ground with water before being fed into the kiln.
What are the two methods of manufacturing of cement?
Cement Manufacturing Process Cement manufacturing process involves various raw materials and processes. Cement is a greenish grey coloured powder, made of calcined mixtures of clay and limestone. When mixed with water becomes a hard and strong building material.It was first introduced by a British stone mason, Joseph Aspdin in 1824, who cooked cement in his kitchen.
- Cement is first used in the tunnel construction in the Thames River in 1828.
- Manufacturing Process of Cement
- There are four stages in this whole process.• Mixing of raw material• Burning• Grinding
- • Storage and packaging
- Mixing of raw material
Calcium, Silicon, Iron and Aluminium are the raw materials used majorly in manufacture of cement. There are two methods of mixing. Dry Process and Wet Process.
- Dry Process: The both calcareous and argillaceous raw materials are firstly crushed in the gyratory crushers to get 2-5cm size pieces separately. The crushed materials are again grinded to get fine particles into ball or tube mill. After screening this finely grinded materials are stored in hopper. Then powdered minerals are mixed and dry raw mix is stored in silos and ready to be sent into rotary kiln.
- Wet Process : In this process first raw materials are crushed and made into powdered form and stored in silos. Then clay is washed and sticky organic matters are removed. Then powdered limestone and water washed clay are sent to flow in the channels and transfer to grinding mills where they are completely mixed and the paste is formed. Then grinding process is done in a ball or tube mill or even both. Then the slurry is led into collecting basin where composition can be adjusted. The slurry contains around 38-40% water that is stored in storage tanks and kept ready for the rotary kiln.
Burning of Raw Materials This process is carried out in rotary kiln while the raw materials are rotated at 1-2rpm at its longitudinal axis. The raw mix of dry process of corrected slurry of wet process is injected into the kiln from the upper end. Powdered coal or oil or hot gases are used to be heated up from the lower end of the kiln so that the long hot flames is produced.
- The lower part (clinkering zone) have temperature in between 1500-1700 degree Celsius where lime and clay are reacts to yielding calcium aluminates and calcium silicates.
- This aluminates and silicates of calcium fuse to gather to form small and hard stones are known as clinkers.
- The size of the clinker is varies from 5-10mm.
The clinker coming from the burning zone are very hot. To bring down the temperature of clinkers, air is admitted in counter current direction at the base of the rotary kiln. The cooled clinkers are collected in small trolleys. Grinding of clinkers The cooled clinkers are received from the cooling pans and sent into mills.
- Storage and packaging The grinded cement is stored in silos, from which it is marketed either in container load or 50kg bags.
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: Cement Manufacturing Process
What is the production of cement in India?
Compound Annual Growth Rate (CAGR) in production of cement in India is 5.59%. while in consumption is 5.20%. It is expected to achieve 550-600 Million Tonnes per annum (MTPA) constantly by 2025 because of the expanding requests of different divisions’ i.e. housing, commercial construction and industrial construction.
What is the manufacturing process of concrete?
What Are The Manufacturing Process Of Concrete | Process Of Manufacture Of Concrete MANUFACTURING OF CONCRETE While manufacturing concrete, it should be ensured that every batch of concrete has the same proportions. This is a mandatory requirement so as to satisfy two aspects, viz., same workability and uniform strength. In the manufacturing of concrete the following steps are followed:
- 1. Proportioning of concrete
- 2. Batching of materials
- 3. Mixing of concrete
- 4. Conveyance of concrete
- 5. Placing of concrete
- 6. Compaction of concrete
- 7. Curing of concrete
PROPORTIONING OF CONCRETE Selection of the proper quantity of cement, coarse aggregate, sand and water to obtain the desired quality is known as proportioning of concrete. Concrete is formed by successive filling of voids in aggregate by sand, the voids in the sand by cement and voids in cement by water and undergoing a chemical reaction.
- The concrete formed by proper proportioning of ingredients should satisfy the following properties:
- (i) The fresh concrete should have adequate workability for uniform placement.
- (ii) The hardened concrete after setting should have the desired strength and durability.
- (iii) The concrete should be cheap considering the materials and labour.
There are two approaches to proportioning concrete. In the first method, no preliminary tests are conducted. But based on experience, arbitrary ratios such as 1:2:4; 1:1½:3; 1:1:2, etc., are used. This method of proportioning by adopting an arbitrary ratio is called the mixing method, and the concrete formed by this method is called ordinary concrete.
This type of concrete is used for ordinary or common works such as columns and members subjected to medium loads, all general building RCC works, mass concrete work in culverts, retaining walls, compound walls, and ordinary machine bases. Ordinary concrete can also be used for long-span arches with a mix of 1:1:2 and for heavily stressed members with a mix of 1:2:2.
In the second method, preliminary tests are conducted, the mix being designed by any one of the mix design methods to get the desired strength and durability. The concrete formed by this method is called controlled concrete. This type of concrete is used for all plain and reinforced concrete structures.
|Sl. No.||Desired strength (kg/cm 2 )||Preliminary test value (kg/cm 2 )|
BATCHING OF MATERIALS After fixing, the desired proportion of the number of required ingredients, viz., cement, coarse- aggregate, fine aggregate, cement and sand, has to be measured out in batches for mixing. This process of measuring out ingredients is called batching.
Batching may be done by weight or by volume. Volume batching is inferior to weight batching as using the former is liable to change the volume of sand in bulking or aggregate constant void feasibility.1. Weight Batching In this batching method, all the ingredients of concrete are directly weighed in kilograms.
As the weight of cement bag is 50 kg, 20 bags are needed for 1 tonne of cement. For all important works, the batching method should be used. This is a slow process.2. Volume Batching In this batching method, two units of measurements are employed: liquids are measured in litres and solids in cubic metres.
- That is all ingredients, viz., water, cement, sand and coarse aggregates are measured in litres, while the end-product concrete is measured in cubic metres.
- In volume batching, other quantities are measured keeping cement as the base.
- Considering that 1 litre of cement equals 1.44 kg, a bag of 50 kg cement has a volume of 3.5 litres.
Hence, for measuring aggregates wooden boxes of an inner volume of 3.5 litres have to be used. Size of a box of 40 cm × 35 cm × 25 cm satisfies this 3.5-litre volume requirement. Handles are provided on the sides for handling. As the density of water is 1 g/ml, it can be measured by weight or by volume.
- The quantity of water required depends on the water-cement ratio.
- Thus, for a water-cement ratio of 0.50, the quantity of water required is 25 litres (0.50 × 50 = 25 litres).
- For accurate batching, the moisture content and absorption of aggregates and bulking of sand have to be ascertained.
- MIXING OF CONCRETE Mixing of concrete may be done by hand or by a machine.
Mixing should be done thoroughly so that the ingredients are uniformly distributed, and this can be judged by the uniform colour and the consistency of concrete. On a clean, hard and water-tight platform cement and sand are mixed dry using shovels until the mixture shows a uniform colour.
- Then aggregates are added and the ingredients are thoroughly mixed.
- Based on the water-cement ratio, the quantity of water required is calculated and added to the dry mix.
- The mass is then turned to obtain a workable mass and placed in the required area within 30 minutes.
- Hand mixing can be used for small quantities of concrete, or due to the non-availability of a machine or where the noise of the machine should be avoided.
In general, extra cement of 10% is used to compensate for the possible inadequacy. Mixing by machine is always preferred. Concrete mixers are used for mixing concrete and are of two types, viz., (i) continuous mixers and (ii) batch mixers. Continuous mixers are used for purposes where large quantities of concrete are needed such as dams, bridges, etc.
Batch mixers are also called drum mixers, which consist of drums with blades or baffles inside them, and they are rotated. In the batch mixer, all required materials are fed into the hopper of the revolving drum incorrect quantity. When the mix has attained the desired consistency, the mix is discharged from the drum and conveyed to the concreting yard.
CONVEYANCE OF CONCRETE The mixed concrete should be conveyed to the concreting yard as early as possible but within the initial setting time of the cement. The choice of conveyance depends on several factors, viz., nature of work, distance from the mixing place to the construction site, height to be lifted, type of cement, etc.
During the transit from the point of mixing to the point of placement, the following factors have to be borne in mind: 1. Care should be taken not to allow segregation of aggregates.2. The containers of the drums should be tight such that there is a minimum loss of water.3. The mixed concrete should be brought to the site before the initial setting time of the cement.
For ordinary simple works, a temporary ladder is erected to convey the concrete using baskets, or it is passed from hand to hand, i.e., by manual labour. For larger and important works, various mechanical devices such as vertical hoists, lift wells for tall structures, wheelbarrows, etc., are used.
- COMPACTION OF CONCRETE Compaction of concrete has to be done as early as possible after placing the concrete in place.
- The purpose of compaction is to expel air and bring the particles closer so as to reduce the void and make the concrete denser.
- This increased density will give higher strength and make the concrete impermeable.
Over-compaction leads to segregation while under-compaction makes the concrete lean. To check for correct compaction, the compaction should be stopped as soon as the cement paste starts appearing on the upper surface of the concrete. Compaction by hand may be performed by rodding, tamping, ramming or hammering.
- Compaction by machines is performed using mechanical vibrators. This method of compaction has several advantages as detailed below:
- (i) The concrete produced is dense and impermeable.
- (ii) A lesser water-cement ratio results in about 15% reduction in the use of cement.
- (iii) A better bond exists between steel and concrete.
- (iv) The surface of the concrete is uniform because of machine compaction.
- (v) Because of a high aggregate–cement ratio, there is a possibility for the reduction in creep and shrinkage.
- (vi) Filling small openings is feasible because of good consistency in concrete.
- (vii) It is relatively fast in placing concrete.
- (viii) It consumes comparatively less time, materials and labour and is hence economical.
- CURING OF CONCRETE
- The following methods of curing are adopted depending on the type of work:
- 1. Direct Curing
In this method, water is directly applied to the surface of curing. In this process, the surface is continuously cured by stagnating water or using moist gunny bags, straws, etc. These methods are used for horizontal surfaces. Vertical surfaces can be cured by covering moist gunny bags or straws.2.
Membrane Curing In this method, steps are taken to prevent water evaporation from finished concrete sur- faces. This is done by covering the surfaces with water-proof papers, polythene papers or by spraying with patented compounds or covering with a bituminous layer to form an impervious film on the concrete surface.3.
Steam Curing This approach is widely used in precast concrete units. Here the precast units are kept under the warm and damp atmosphere of a steam chamber.4. Surface Application by Chemicals Chemicals such as calcium chloride are spread as a layer on the finished concrete.
What is cement and how it is manufactured?
Portland cement – Portland cement, a form of hydraulic cement, is by far the most common type of cement in general use around the world. This cement is made by heating limestone (calcium carbonate) with other materials (such as clay ) to 1,450 °C (2,640 °F) in a kiln, in a process known as calcination that liberates a molecule of carbon dioxide from the calcium carbonate to form calcium oxide, or quicklime, which then chemically combines with the other materials in the mix to form calcium silicates and other cementitious compounds.
The resulting hard substance, called ‘clinker’, is then ground with a small amount of gypsum ( CaSO 4 ·2H 2 O ) into a powder to make ordinary Portland cement, the most commonly used type of cement (often referred to as OPC). Portland cement is a basic ingredient of concrete, mortar, and most non-specialty grout,
The most common use for Portland cement is to make concrete. Portland cement may be grey or white,
How cement is manufactured by dry process?
2. Cement Plants – Portland cement manufacture accounts for about 98% of the cement production in the United States. The raw materials are crushed, processed, proportioned, ground, and blended before going to the final process, which may be either wet or dry.
- In the dry process, the moisture content of the raw material is reduced to less than 1% before the blending process occurs.
- The dry material is pulverized and fed to the rotary kiln.
- Further drying, decarbonating, and calcining take place as the material passes through the rotary kiln.
- The material leaves the kiln as clinker, which is cooled, ground, packaged, and shipped.
For the wet process, a slurry is made by adding water during the initial grinding. The homogeneous wet mixture is fed to the kiln as a wet slurry (30–40% water) or as a wet filtrate (20% water). The burning, cooling, grinding, packaging, and shipping are the same as for the dry process.
|Pollutant||Emissions (kg metric ton −1 )|
|Dry process||Wet process|
|Kilns||Dryers, grinders, etc.||Kilns||Dryers, grinders, etc.|
|Sulfur dioxide a||5.1|
|Gas combustion||2.1 × S b||—||Neg||—|
|Oil combustion||3.4 × S||—||2.1 × S b||—|
|Coal combustion||—||3.4 × S||—|
a If a baghouse is used as control device, reduce SO 2 by 50% because of reactions with an alkaline filter cake. b S is the percent of sulfur in the fuel. Source: Ref. Control of particulate matter emissions from the kilns, dryers, grinders, etc. is by means of standard devices and systems: (1) multiple cyclones (80% efficiency), (2) ESPs (95% + efficiency), (3) multiple cyclones followed by ESPs (97.5% efficiency), and (4) baghouses (99.8% efficiency).
What are the two uses of cement industry?
Where is cement used? – Cembureau Airports | Green roofs | Bridges | Water pipes | Grain silos | Tunnel | Multi storey car parks | Elevated trains | Swimming pools | High rise office buildings | Water reservoirs | Dikes | Wind Power | Roads | Dams | Cargo ships | Statues | Stairs |High rise residential buildings | Houses Cement plays a key, but often unnoticed, role in our lives.
Cement is mainly used as a binder in concrete, which is a basic material for all types of construction, including housing, roads, schools, hospitals, dams and ports, as well as for decorative applications (for patios, floors, staircases, driveways, pool decks) and items like tables, sculptures or bookcases.
Concrete is a versatile and reliable construction material with a wide range of applications. When looking at possible pathways to reduce the carbon footprint of the European cement industry, it is important to examine some of the characteristics of the industry that will influence the availability or viability of emission reduction options. The cement industry is CO 2 -, energy- and material-intensive. Measures to decrease energy consumption and to improve resource efficiency will de facto, reduce CO 2 emissions (hence the focus on CO 2 emissions). The combination of process emissions (emissions released when limestone is transformed into lime during the production process) and emissions from the required thermal energy leads to substantial CO2emissions for each tonne of cement. The cost of constructing a new cement plant with 1 million tonnes of annual capacity is typically more than €150 million. Modernisation of existing cement plants is also very expensive. In addition, and in order to meet European environmental legislation, operations face major investments and operating costs.30% of the cement industry’s total operating expenses relate to energy costs.
The cost of a new cement plant is equivalent to around three years of turnover, which ranks the cement industry among the most capital-intensive industries. Long periods are therefore needed before these large investments can be recovered. Plant modifications have to be carefully planned, as typical investment cycles in the sector last about 30 years.
Consequently, achieving the 2050 low-carbon economy roadmap for the European cement industry will be based on balancing recent investments with planning new investments in the coming decades. Although produced from naturally occurring raw materials that can vary widely from plant to plant, cement is a product manufactured in Europe according to a harmonised standard. Despite the existence of specialised segments, many cements are interchangeable, which promotes a competitive cement market. This also means that European production can be very vulnerable to cheaper imports. Cement is mostly locally produced and locally consumed. However, it is also transported over long distances by sea, river and land as plants rationalise and exploit efficiencies of scale. Land transportation costs are significant. Transporting cement costs about €10 per tonne for every 100km by road and around €15 per tonne to cross the Mediterranean Sea 2, Cement consumption is closely linked to economic development in the local region or country. In mature markets, such as Europe, where cement consumption per capita still varies considerably from one country to another, cement sales are dependent on activity in the construction sector, which closely follows (usually after a brief delay) general economic activity.
Is cement industry an oligopoly?
The global cement industry can be characterised as a network of regional oligopoly markets. As cement is a relatively homogenous product globally, differences in world market prices largely reflect differences in local production costs and high transportation costs.
What is the status of production of cement?
Cement production in India increased by 19.4% in June 2022 compared to June 2021.
What is concrete production equipment?
Dry Mix Concrete Plant – A dry mix concrete plant, also known as a transit mix plant, weighs sand, gravel and cement in weigh batchers via digital or manual scales. All the ingredients are then discharged into a chute, which discharges into a truck. Meanwhile, water is either being weighed or volumetrically metered and discharged through the same charging chute into the mixer truck.
How many method of cementing are there?
Basic Civil Engineering Questions and Answers – RCC, PSC and Ferro-Cement This set of Basic Civil Engineering online quiz focuses on “RCC, PSC and Ferro-Cement”.1.R.C.C. can be classified into: a) 2 b) 3 c) 4 d) 5 View Answer Answer: a Explanation: Reinforced cement concrete can be of two types. It can either be pre-cast or be casted in-situ.
2. PSC stands for: a) Post-Stressed Concrete b) Post-Strained Concrete c) Pre-Stressed Concrete d) Pre-strained Concrete View Answer
Answer: c Explanation: Pre-Stressed Concrete refers to the block of concrete which has been subjected to compression prior to supporting any loads.3. _ is used to construct very thin, hard and strong surface: a) R.C.C. b) PSC c) PCC d) Ferro-Cement View Answer Answer: d Explanation: Ferro-Cement is a system that reinforces mortar with metal (steel, iron bars).
It is used for the construction of relatively thin structure like hull of boat, shell roofs, etc. Note: Join free Sanfoundry classes at or 4. The compression in PSC is done by _ of high-strength tendons. a) Compression b) Tensioning c) Shearing d) Bending View Answer Answer: b Explanation: Tendons can be a single wire, mesh, threaded bars made from high tensile steels.
The pre-stressing is done by tensioning tendons.5. In an R.C.C structure, the tension zone lies in the: a) Top b) Middle c) Side d) Bottom View Answer Answer: d Explanation: In the R.C.C. structure, there is a neutral axis in the middle, where no compression and tension is there.
- Layers above it are subjected to compression and the ones below it is subjected to tension.
- Take Now! 6.R.C.C.
- Was developed and first used by: a) Joseph Monier b) John Smeaton c) Francois Coignet d) Joseph Asphadin View Answer Answer: c Explanation: Joseph Monier founded ferro-cement.
- John Smeaton is considered the father of Civil Engineering.
Joseph Asphdin founded Portland cement. Francois Coignet was a French industrialist and the first to use iron-reinforced concrete.7. Which of the below structure doesn’t require PSC? a) Bridge b) Arch c) Dam d) Silos View Answer Answer: b Explanation: Arches don’t require PSC.
- They are not under so much compression and loading.
- All other structures carry heavy loads and hence will be efficient if PSC is used.8.
- How many methods of ferro cementing are there? a) 3 b) 2 c) 4 d) 6 View Answer Answer: a Explanation: The three methods are armature system, closed mould system and integrated mould system.9.
In which beam tension capacity of steel is greater than combined compression capacity of steel and concrete? a) Over-reinforced b) Under-reinforced c) Singly reinforced d) Doubly reinforced View Answer Answer: a Explanation: Over-reinforced beams have higher tension capacity.
- So, these beams fail by crushing of compression zone concrete, without any warning.10.
- In a PSC, the tensioning system may be classified into: a) 3 b) 2 c) 5 d) 4 View Answer Answer: b Explanation: Tensioning can be mono-strand or multi-strand.
- In mono-strand, only one strand is tensioned at a time.
- In multi-strand, multiple strands are tensioned simultaneously.11.
Which of the below is not a property of ferro cement? a) Impervious nature b) Capacity to resist shock c) No need of formwork d) Strength per unit mass is low View Answer Answer: d Explanation: The ferro cement has reinforcement provided in mortar. It has a strength per unit mass higher than R.C.C.
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