What is the manufacturing process of Portland Cement?
History of Portland Cement
A brief information about Portland Cement
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed for other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and usually originates from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, grinding the clinker, and adding 2-3% percent of GYPSUM. Several types of Portland cement are available. The most common, called ordinary Portland cement (OPC), is grey, but white Portland cement is also available.
The inventor of Modern Portland Cement
Portland cement was developed from natural cements made in Britain beginning in the middle of the 18th century. Its name derives from its similarity to Portland stone, a type of building stone quarried on the Isle of Portland in Dorset, England.
The development of modern Portland cement (sometimes called ordinary or normal Portland cement) began in 1756, when John Smeaton experimented with combinations of different limestones and additives, including trass and pozzolanas, relating to the planned construction of a lighthouse, now known as Smeaton’s Tower.
In the late 18th century, Roman cement was developed and patented in 1796 by James Parker. Roman cement quickly became popular, but was largely replaced by Portland cement in the 1850s. In 1811, James Frost produced a cement he called British cement.
James Frost is reported to have erected a manufactory for making of an artificial cement in 1826.In 1811 Edgar Dobbs of Southwark patented a cement of the kind invented 7 years later by the French engineer Louis Vicat. Vicat’s cement is an artificial hydraulic lime, and is considered the ‘principal forerunner’ of Portland cement.
The name Portland cement is recorded in a directory published in 1823 being associated with a William Lockwood and possibly others. In his 1824 cement patent, Joseph Aspdin called his invention “Portland cement” because of its resemblance to Portland stone. However, Aspdin’s cement was nothing like modern Portland cement, but was a first step in the development of modern Portland cement, and has been called a ‘proto-Portland cement’.
William Aspdin had left his father’s company, to form his own cement manufacturing. In the 1840s, William Aspdin, apparently accidentally, produced calcium silicates which are a middle step in the development of Portland cement.
In 1848, William Aspdin further improved his cement. Then, in 1853, he moved to Germany, where he was involved in cement making.
William Aspdin made what could be called ‘meso-Portland cement‘ (a mix of Portland cement and hydraulic lime).Isaac Charles Johnson further refined the production of ‘meso-Portland cement’ (middle stage of development), and claimed to be the real father of Portland cement.
In 1859, John Grant of the Metropolitan Board of Works, set out requirements for cement to be used in the London sewer project. This became a specification for Portland cement.
The next development in the manufacture of Portland cement was the introduction of the rotary kiln, patented by Frederick Ransome in 1885 (U.K.) and 1886 (U.S.); which allowed a stronger, more homogeneous mixture and a continuous manufacturing process.
The Hoffmann ‘endless’ kiln which was said to give ‘perfect control over combustion’ was tested in 1860, and showed the process produced a better grade of cement. This cement was made at the Portland Cementfabrik Stern at Stettin, which was the first to use a Hoffmann kiln. The Association of German Cement Manufacturers issued a standard on Portland cement in 1878.
Portland cement had been imported into the United States from Germany and England, and in the 1870s and 1880s, it was being produced by Eagle Portland cement near Kalamazoo, Michigan. In 1875, the first Portland cement was produced in the Coplay Cement Company Kilns under the direction of David O. Saylor in Coplay, Pennsylvania.By the early 20th century, American-made Portland cement had displaced most of the imported Portland cement.
How cement is made? A brief story of manufacturing
Before a full information about each section of Cement manufacturing, let us take a look at all procedures of Portland Cement production from first step (Raw Materials and Chemical combination) to the final stage (Cement Packing) briefly.
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 to 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.
Before a full information about each section of Cement manufacturing, let us take a look at all procedures of Portland Cement production from first step (Raw Materials and Chemical combination) to the final stage (Cement Packing) briefly.
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 to 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 larger 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 is Portland Cement made of?
For the bulk and continuous manufacturing and production of Portland Cement following mineral materials are used:
- calcareous materials -CaCO3 > 75% such as limestone, marl, chalk,
- argillaceous material -CaCO3 < 40% such as clay and shale-,
- blast furnace slag,
- silica sand,
- iron ore, and
- gypsum
as raw material.
Cement factories are established where these raw materials are available in plenty and facilities of long-distance transportation of raw and finished materials.
The manufacture of Portland cement is a complex process and done in the following steps:
1) Grinding the raw materials,
2) Mixing them in certain proportions depending upon their purity and composition, and
3) Burning them to sintering in a kiln at a temperature of about 1350 to 1500 ⁰C.
During this process, these materials partially fuse to form nodular shaped clinker by breaking of chemical bonds of the raw materials and recombined into new compounds.
The clinker is cooled and ground to a fine powder with the addition of about 3 to 5% of gypsum. By this process, the product formed is Portland cement.
Mixing of Raw Materials
The major raw materials used in the manufacture of cement are Calcium, Silicon, Iron and Aluminum. These minerals are used in different form as per the availability of the minerals.
- Table of Raw Materials for Portland Cement manufacture
Calcareius Material | Argillaceous Material | ||
Calcium | Silicon | Aluminium | Iron |
Limestone | Clay | Clay | Clay |
Marl | Marl | Shale | Iron Ore |
Calcite | Sand | Fly Ash | Mill Scale |
Aragonite | Shale | Aluminium Ore Refuse | Shale |
Shale | Fly Ash | Blast Furnace Dust | |
Sea Shells | Rice hull Ash | ||
Cement Kiln Dust | Slag | ||
The mixing procedure of the manufacture of cement is done in 2 methods:
- WET PROCESS
- DRY PROCESS
Two animated videos and one video about Portland Cement Manufacturing by Wet Process and Dry Process
In these animated video you can see WET and DRY process in Cement Manufacturing and another video about Cement Production’s simulation at one of cement factories. In 2nd video you can see full details of each section of manufacturing of Portland cement, one by one in 4 minutes briefly.
In 3rd video you can see the production of Portland cement from Quarrying to the end procedures in on cement factory.
Types of Manufacturing of cement
WET PROCESS
In the wet process, first of all, the newly quarried limestone is crushed into smaller pieces. Then in the ball or tube mill, it is mixed with clay or shale with water to form a slurry. The slurry is a liquid of creamy consistency with a water content of about 35 to 50 percent, wherein particles, crushed to the fineness are held in suspension.
Then this slurry is pumped into slurry tanks or basins. In that tank, the limestone and clay particles are prevented to settle by blowing compressed air from the bottom of slurry are kept in ignited condition with help of rotating arms with chains.
This slurry is maintained at the required chemical composition in a tube mill by testing and correcting time to time. Also tested in the different storage tanks by blending the slurry. After that, in the final storage tanks by the agitation of slurry, it is kept inhomogeneous condition.
One of the important parts of the cement production plant is the rotary kiln. That homogeneous corrected slurry is applied by nozzle spray on the upper end of the rotary kiln. Rotary kiln is a 3m to 8m diameter steel cylinder, lined with fire resistance refractory materials, fitted on roller bearings and capable of rotating about its own axis at a designed speed.
The length of the rotary kiln may vary anything from 30 meters to 200 meters. The slurry on being sprayed against a hot surface of a flexible chain loses moisture and becomes flakes. These flakes peel off and fall on the floor. The rotation of the rotary kiln causes the flakes to move from the upper end towards the lower end of the kiln subjecting itself to higher and higher temperatures.
The kiln is fired from the lower end. Normally for the manufacturing of cement, the fuel used are powdered coal, oil or natural gas. As the materials go ahead then, the material rolls down to the lower end of the rotary kiln, the dry material undergoes a series of chemical reactions until finally, in the hottest part of the kiln, where the temperature is in the order of 1500°C, about 20 to 30 percent of the materials get fused. Lime, silica, and alumina get recombined. This is where the oxides in raw materials will be combined to form compounds in the clinker.
The fused mass turns into a nodular form of size 3 mm to 20 mm known as clinker. Then, the clinker is cooled under controlled conditions in a rotary cooler. The clinker is stored in silos or bins. Generally, the clinker weighs about 1100 to 1300 gms per liter. The liter weight of the clinker indicates the quality of the clinker.
Then, cooled clinker ground in a ball mill. For the prevention of flash-setting of the cement 3 to 5 % of gypsum is added. Ball mill is a hardened steel ball that has different chambers that charged in sequence forward. The particles are crushed into the required fineness level. And particles are separated by air currents and taken to storage. Then, supply to the market as a final product and uses in various construction works such as Buildings, pavements, dams or other large work sites.
In the modern method of grinding, a well-graded cement particle is formed by the particle size distribution of cement particles.
Video about Portland Cement Manufacturing by Wet Process
In this animated video, you can see all procedures about Portland cement manufacturing by Wet Process.
DRY PROCESS
In the dry and semi-dry process the raw materials are crushed in a dry state. Then, they are processed in grinding mill, dried and reduced to very fine powder-like. That dry power is further blended, corrected for the right composition and mixed with the flow of compressed air. Nearly about one hour of aeration, a uniform mixture is obtained, that aerated power tends to behave like a liquid.
Then, the blended meal is sieved and apply to process in a rotating disc called Granulator. A quantity of water about 12 percent by weight is added to make the blended meal into pellets.
The blended meal is converted into pellets by the addition of water about 12 percent by weight. This is done for the easy exchange of heat by airflow during the further chemical reaction.
Smaller types of equipment are used in dry process comparative to wet process and dry process is also economical.
Nowadays, many cement factories used modern production technology to increase capacity and quality of cement.
In modern technology, they use the equipment, such as a cross belt analyzer manufactured by Gamma-Metrics of USA to find the composition of limestone at the conveyor belts, high-pressure twin roller press, six-stage preheater, and vertical roller mill. The latest Technology with a modern control system includes stacker and reclaimer, on-line X-ray analyzer, Fuzzy Logic kiln, and other process control.
It is important to note that the strength properties of cement are considerably influenced by the cooling rate of the clinker. The rate of cooling influences the degree of crystallization, the size of the crystal and the number of amorphous materials present in the clinker.
The properties of this amorphous material for similar chemical composition will be different from the one which is crystallized. This all about the manufacturing of cement.
One of the interesting points about cement is that the strength properties of cement depend upon the cooling rate of the clinker, because the rate of cooling influences the degree of crystallization, the size of the crystal and the number of amorphous materials present in the clinker.
Comparison of dry process and wet process of Cement Manufacture
| Criteria | Dry process | Wet process |
| Hardness of raw material | Quite hard | Any type of raw material |
| Fuel consumption | Low | High |
| Time of process | Lesser | Higher |
| Quality | Inferior quality | Superior quality |
| Cost of production | High | Low |
| Overall cost | Costly | Cheaper |
| Physical state | Raw mix (solid) | Slurry (liquid) |
Chemical shorthand
Because of the complex chemical nature of cement, a shorthand form is used to denote the chemical compounds. The shorthand for the basic compounds is:
Compound | Formula | Shorthand form |
Calcium oxide (lime) | Ca0 | C |
Silicon dioxide (silica) | SiO2 | S |
Aluminum oxide (alumina) | Al2O3 | A |
Iron oxide | Fe2O3 | F |
Water | H2O | H |
Sulfate | SO3 | S |
Chemical composition of clinker
The cement clinker formed has the following typical composition:
Compound | Formula | Shorthand form | % by weight1 |
Tricalcium aluminate | Ca3Al2O6 | C3A | 10 |
Tetracalcium aluminoferrite | Ca4Al2Fe2O10 | C4AF | 8 |
Belite or dicalcium silicate | Ca2SiO5 | C2S | 20 |
Alite or tricalcium silicate | Ca3SiO4 | C3S | 55 |
Sodium oxide | Na2O | N | Up to 2 |
Potassium oxide | K2O | K | |
Gypsum | CaSO4.2H2O | CSH2 | 5 |
(1) Representative weights only. Actual weight varies with type of cement.
Source: Mindess & Young
Properties of cement compounds
These compounds contribute to the properties of cement in different ways
- Tricalcium aluminate, C3A:-
It liberates a lot of heat during the early stages of hydration, but has little strength contribution. Gypsum slows down the hydration rate of C3A. Cement low in C3A is sulfate resistant. - Tricalcium silicate, C3S:-
This compound hydrates and hardens rapidly. It is largely responsible for portland cement’s initial set and early strength gain. - Dicalcium silicate, C2S:
C2S hydrates and hardens slowly. It is largely responsible for strength gain after one week. - Ferrite, C4AF:
This is a fluxing agent which reduces the melting temperature of the raw materials in the kiln (from 3,000oF to 2,600o F). It hydrates rapidly, but does not contribute much to strength of the cement paste.
By mixing these compounds appropriately, manufacturers can produce different types of cement to suit several construction environments.
Portland Cement Composition
Composition of cement
Introduction
Portland cement gets its strength from chemical reactions between the cement and water. The process is known as hydration. This is a complex process that is best understood by first understanding the chemical composition of cement.
Manufacture of cement
Portland cement is manufactured by crushing, milling and proportioning the following materials:
- Lime or calcium oxide, CaO: from limestone, chalk, shells, shale or calcareous rock
- Silica, SiO2: from sand, old bottles, clay or argillaceous rock
- Alumina, Al2O3: from bauxite, recycled aluminum, clay
- Iron, Fe2O3: from from clay, iron ore, scrap iron and fly ash
- Gypsum, CaSO4.2H20: found together with limestone
The materials, without the gypsum, are proportioned to produce a mixture with the desired chemical composition and then ground and blended by one of two processes – dry process or wet process. The materials are then fed through a kiln at 2,600º F to produce grayish-black pellets known as clinker. The alumina and iron act as fluxing agents which lower the melting point of silica from 3,000 to 2600º F. After this stage, the clinker is cooled, pulverized and gypsum added to regulate setting time. It is then ground extremely fine to produce cement.
A brief video about all Portland Cement manufacturing process- from Raw materials to the final stage that is cement powder.
Burning of Raw Materials
The burning process is carried out in the rotary kiln while the raw materials are rotated at 1-2 rpm at its longitudinal axis. The rotary kiln is made up of steel tubes having the diameter of 2.5-3.0 meter and the length differs from 90-120meter.
The inner side of the kiln is lined with refractory bricks.
The kiln is supported on the columns of masonry or concrete and rested on roller bearing in slightly inclined position at the gradient of 1 in 25 to 1 in 30. The raw mix of dry process of corrected slurry of wet process is injected into the kiln from the upper end. The kiln is heated with the help of powdered coal or oil or hot gases from the lower end of the kiln so that the long hot flames is produced.
As the kiln position is inclined and it rotates slowly, the material charged from upper end moves towards lower end at the speed of 15m/hr. In the upper part, water or moisture in the material is evaporated at 400oC temp, so this process is known as Drying Zone.
The central part i.e. calcination zone, the temperature is around 10000C, where decomposition of lime stone takes place. The remaining material is in the form of small lumps known as nodules after the CO2 is released.
CaCO3 = CaO + CO2
A video about Lime Kiln Fundumentals
The lower part (clinkering zone) have temperature in between 1500-17000C 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 lower part i.e. clinkering zone has the temperature around 1500-1700C. In the region lime and clay reacts to yield calcium aluminates and calcium silicates. This products of aluminates and silicates of calcium fuses together to form hard and small stones known as clinkers. The size of the small and hard clinkers varies from 5 to 10mm.
2CaO + SiO2 = Ca2SiO4 (declaim silicate (C2S))
3CaO + SiO2 = Ca3SiO5 (tricalcium silicate (C3S))
3CaO + Al2 O3 = Ca2 Al2 O6 (dicalcium aluminate (C2A))
4CaO + Al2 O3 + Fe2 O3 = Ca4 Al2 Fe2 O10 (tetracalcium aluminoferrite(C4AF)
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.
Video Clips about Cement Manufacturing
Grinding of Clinkers
The cooled clinkers are received from the cooling pans and sent into mills. The clinkers are grinded finely into powder in ball mill or tube mill. Powdered gypsum is added around 2-3% as retarding agent during final grinding. The final obtained product is cement that does not settle quickly when comes in contact with water.
After the initial setting time of the cement, the cement becomes stiff and the gypsum retards the dissolution of tri-calcium aluminates by forming tricalcium sulfoaluminate which is insoluble and prevents too early further reactions of setting and hardening.
3CaO.Al2O3 + xCaSO4.7H2O = 3CaO.Al2O3 xCaSO4.7H2O
A video about Cement Packing in UltraTech Cement Factory
Storage and Packaging
The grinded cement is stored in silos, from which it is marketed either in container load or 50kg bags.
A video by FLSmith- How to build a cement plant?
Portland Cement Types and Standards
To ensure a level of consistency between cement-producing plants, certain chemical and physical limits are placed on cements. These chemical limits are defined by a variety of standards and specifications.
For instance, portland cements and blended hydraulic cements for concrete in the U.S. conform to the American Society for Testing and Materials (ASTM) C150 (Standard Specification for Portland Cement), C595 (Standard Specification for Blended Hydraulic Cement) or C1157 (Performance Specification for Hydraulic Cements).
Some state agencies refer to very similar specifications: AASHTO M 85 for portland cement and M 240 for blended cements. These specifications refer to standard test methods to assure that the testing is performed in the same manner. For example, ASTM C109 (Standard Test Method for Compressive Strength for Hydraulic Cement Mortars using 2-inch Cube Specimens), describes in detail how to fabricate and test mortar cubes for compressive strength testing in a standardized fashion.
An EN (European Standard) “carries with it the obligation to be implemented at national level by being given the status of a national standard and by withdrawal of any conflicting national standard”. Therefore, a European Standard (EN) automatically becomes a national standard in each of the 34 CEN-CENELEC member countries.
For portland Cement, EN 197-1 Standard is related to Types and specification of Portland Cement.
Nomenclature Differences
In the US, three separate standards may apply depending on the category of cement. For portland cement types, ASTM C150 describes:
Cement Type Description
Type I Normal
Type II Moderate Sulfate Resistance
Type II (MH) Moderate Heat of Hydration (and Moderate Sulfate Resistance)
Type III High Early Strength
Type IV Low Heat Hydration
Type V High Sulfate Resistance
– Type I—The standard product that has long been in use with no limitation on the proportions of the major oxides (CaO, SiO2, Al2O3, Fe2O3), also referred to as “ordinary portland cement.”
– Type II—This cement possesses moderate resistance to sulfate attack because of certain limitations on composition. Sometimes called moderate-heat cement, it is intermediate between Type I and the low-heat Type IV cement. If moderate heat of hydration is desired, however, the optional limit on heat of hydration should be invoked when specifying or ordering.
– Type III—High-early-strength portland cement is often produced by grinding Type I clinker finer or by altering the chemical composition of the cement.
– Type IV—Low-heat portland cement. Not currently made in the United States and limited in production elsewhere.
– Type V—Sulfate-resisting portland cement with appropriate limits on composition.
For blended hydraulic cements – specified by ASTM C595 – the following nomenclature is used:
Cement Type Description
Type IL Portland-Limestone Cement
Type IS Portland-Slag Cement
Type IP Portland-Pozzonlan Cement
Type IT Ternary Blended Cement
In addition, some blended cements have special performance properties verified by additional testing. These are designated by letters in parentheses following the cement type. For example Type IP(MS) is a portland-pozzolan cement with moderate sulfate resistance properties. Other special properties are designated by (HS), for high sulfate resistance; (A), for air-entraining cements; (MH) for moderate heat of hydration; and (LH) for low heat of hydration. Refer to ASTM C595 for more detail.
However, with an interest in the industry for performance-based specifications, ASTM C1157 describes cements by their performance attributes:
Cement Type Description
Type GU General Use
Type HE High Early-Strength
Type MS Moderate Sulfate Resistance
Type HS High Sulfate Resistance
Type MH Moderate Heat of Hydration
Type LH Low Heat of Hydration
- You can find more details about Portland cement standards in the following links:
ASTM C-150 Standard
ASTM C150 defines Portland cement as: hydraulic cement (cement that not only hardens by reacting with water but also forms a water-resistant product) produced by pulverizing clinkers which consist essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an inter ground addition.
EN 197-1 Standard
The European Standard EN 197-1 uses the following definition: Portland cement clinker is a hydraulic material which shall consist of at least two-thirds by mass of calcium silicates, (3 CaO·SiO2, and 2 CaO·SiO2), the remainder consisting of aluminium- and iron-containing clinker phases and other compounds. The ratio of CaO to SiO2 shall not be less than 2.0. The magnesium oxide content (MgO) shall not exceed 5.0% by mass.
European Portland Cement Standards:
- EN 197-1: Cement – Part 1: Composition, specifications and conformity criteria for common cements
- EN 197-2: Cement – Part 2 : Conformity evaluation
Environmental effects
Portland cement manufacture can cause environmental impacts at all stages of the process. These include emissions of airborne pollution in the form of:
- Dust;
- Gases;
- Noise, and Vibration when operating machinery and during blasting in quarries;
- Consumption of large quantities of fuel during manufacture;
- Release of CO2 from the raw materials during manufacture, and damage to countryside from quarrying.
Equipment to reduce dust emissions during quarrying and manufacture of cement is widely used, and equipment to trap and separate exhaust gases are coming into increased use. Environmental protection, also includes the re-integration of quarries into the countryside after they have been closed down by returning them to nature or re-cultivating them.
Epidemiologic Notes and Reports Sulfur Dioxide Exposure of Portland Cement Plants, from the Centers for Disease Control, states:
Workers in Portland cement facilities, particularly those burning fuel containing sulfur, should be aware of the acute and chronic effects of exposure to SO2 [sulfur dioxide], and peak and full-shift concentrations of SO2 should be periodically measured.
An independent research effort of AEA Technology to identify critical issues for the cement industry today concluded the most important environment, health and safety performance issues facing the cement industry are atmospheric releases (including greenhouse gas emissions, dioxin, NOx, SO2, and particulates), accidents, and worker exposure to dust.
The CO2 associated with the Portland cement manufacture comes mainly from four sources:
No | CO2 Source | Amount |
1 | De carbonation of limestone | Constant: minimum around 0.47 kg CO2 per kg of cement, maximum 0.54, typical value around 0.50 worldwide. |
2 | Kiln fuel combustion | Varies with plant efficiency: efficient pre-calciner plant 0.24 kg CO2 per kg cement, low-efficiency wet process as high as 0.65, typical modern practices (e.g. UK) averaging around 0.30. |
3 | Produced by vehicles in cement plants and distribution | Almost insignificant at 0.002–0.005. So typical total CO2 is around 0.80 kg CO2 per kg, finished cement. |
4 | Electrical power generation | Varies with local power source. Typical electrical energy consumption is approximately 90–150 kWh per ton cement, equivalent to 0.09–0.15 kg CO2 per kg finished cement if the electricity is coal-generated. |
- The thrust of innovation for the future is to reduce sources 1 and 2 by modification of the chemistry of cement, by the use of wastes, and by adopting more efficient processes
- with nuclear or hydroelectric power, and efficient manufacturing, CO2 generation can be reduced.
TOP 10 Cement Producer in the World ranked by cement production in million tonnes
| Rank | Company | Annual Cement Production (Mt/yr) | Cement Production Capacity (Mt/yr) | Country |
| 1 | LafargeHolcim | 286.6 | 386.5 | Switzerland |
| 2 | Anhui Conch Cement | 217.2 | 288.0 | China |
| 3 | CNBM | 176.22 | 406.0 | China |
| 4 | Heidelberg Cement | 121.11 | 129.0 | Germany |
| 5 | Cemex | 87.09 | 93 | Mexico |
| 6 | Italcementi | 76.62 | 77.0 | Italy |
| 7 | China Resources Cement | 71.02 | 78.3 | China |
| 8 | Taiwan Cement | 63.72 | 69.0 | Taiwan |
| 9 | Eurocement | 45.18 | 50 | Russia |
| 10 | Votorantim Group | 45.02 | 54.4 | Brazil |
- For more details about this section you can click on this article on Datis-inc.com:
Top 10 cement companies in the world in 2020
The highest Positive net exports for cement during 2019
The following countries posted the highest positive net exports for cement during 2019.
Investopedia defines net exports as the value of a country’s total exports minus the value of its total imports. Thus, the statistics below present the surplus between the value of each country’s cement exports and its import purchases for that same commodity.
- Vietnam: US$1.3 billion (net export surplus up 104.3% since 2015)
- Turkey: $869.6 million (up 63.3%)
- Thailand: $597.7 million (down -8.1%)
- Canada: $419.7 million (up 107.3%)
- Germany: $371.5 million (up 11%)
- Japan: $307.4 million (down -13.5%)
- Spain: $303.5 million (down -32.5%)
- Saudi Arabia: $223.2 million (reversing a -$45.7 million deficit)
- South Korea: $218.4 million (up 5.2%)
- Ireland: $205.5 million (up 51.2%)
- Greece: $199 million (down -16.6%)
- Indonesia: $165.6 million (reversing a -$128.8 million deficit)
- United Arab Emirates: $125.6 million (down -59.8%)
- Mexico: $124.5 million (up 66.8%)
- Croatia: $113 million (down -8.6%)
Vietnam generated the highest surplus in the international trade of cement. In turn, this positive cashflow confirms Vietnam’s strong competitive advantage for this specific product category.
- For more details about this section you can click on this article on Datis-inc.com :
Top 15 countries exporting Cement in 2019
The Largest Cement Company in the World
LafargeHolcim
LafargeHolcim is the largest cement producer in the world with a presence in 70 countries.
Established through the merger of Lafarge and Holcim in July 2015, the company has a total of 180 plants and an annual production capacity of 386.5 million tonnes. This makes it the biggest cement company in the world.
LafargeHolcim, whose headquarter is located in Switzerland, is also a major manufacturer of aggregate and ready mixed concrete.
LafargeHolcim is a global partner for major infrastructure projects – roads, mines, ports, dams, data centers, stadiums, wind farms, or electric power plants that require major investments.
The group employs around 72,000 people around the world, and reach a combined net sales of CHF 26.7 billion in 2019. The group’s central functions had been divided between Zurich and Paris until the end of 2018, but are currently being transferred to the Swiss cities of Holderbank and Zug.The company’s research facilities are in l’Isle d’Abeau, near Lyon, France.
Headquartered in Switzerland and listed on the SIX Swiss Exchange and on Euronext Paris, LafargeHolcim holds leading positions in all regions across the globe.
| Valor symbol | LHN |
| ISIN | CH0012214059 |
The building materials market is driven by massive global population growth, the shift towards city and urban living and the infrastructure, the highways, bridges, hospitals and schools, that growing populations require.
- A list of the world’s largest cement companies ranked by cement production in million tonnes
| Rank | Company | Annual Cement Production (Mt/yr) | Cement Production Capacity (Mt/yr) | Country |
| 1 | LafargeHolcim | 286.6 | 386.5 | Switzerland |
| 2 | Anhui Conch Cement | 217.2 | 288.0 | China |
| 3 | CNBM | 176.22 | 406.0 | China |
| 4 | Heidelberg Cement | 121.11 | 129.0 | Germany |
| 5 | Cemex | 87.09 | 93 | Mexico |
- For more details about this section you can click on this article on Datis-inc.com :
What is the largest Cement producer in the World?
Worldwide Cement Production from 2015 to 2019
China produces the most cement globally by a large margin, at an estimated 2.2 billion metric tons in 2019, followed by India at 320 million metric tons in the same year.
China currently produces over half of the world’s cement. Global cement production is expected to increase from 3.27 billion metric tons in 2010 to 4.83 billion metric tons in 2030. In China, the cement production in 2018 amounted to some 2.17 million metric tons.
Cement is used to bind material together and is categorized as either non-hydraulic or hydraulic. Hydraulic cements are composed of silicates and oxides that can set and harden even when exposed to water. Cement today is mostly used as stucco for buildings in wet climates, as mortar for applications near sea water, and as part of developments for strong concretes.
Cement consumption in the United States decreased after the 2008 economic downturn, down to 71.5 million metric tons in 2009.
Since then however, consumption has gradually increased to an estimated 102 million metric tons in 2019. In the U.S., most cement is consumed between May and October.
In Europe, CRH, a top cement manufacturer headquartered in Ireland, generated 30.21 billion euros in revenues in 2018.
- For more details about this section you can click on this article on Datis-inc.com :
Worldwide Cement Production From 2015 to 2019
What are the applications of Portland Cement?
Portland cement is an excellent building material generally used for its excellent binding properties giving strength to structural elements. Portland cement is most commonly used for the production of concrete. It is also used as a basic ingredient in the mortar, stucco, and non-specialty grout.
In its simplest form, concrete is a mixture of paste and aggregates. The paste, composed of portland cement and water, coats the surface of the fine and coarse aggregates. Through a chemical reaction called hydration, the paste hardens and gains strength to form the rock-like mass known as concrete.
Within this process lies the key to a remarkable trait of concrete: it’s plastic and malleable when newly mixed, strong and durable when hardened.
Concrete’s durability, strength and relatively low cost make it the backbone of buildings and infrastructure worldwide—houses, schools and hospitals as well as airports, bridges, highways and rail systems. The most-produced material on Earth will only be more in demand as, for example, developing nations become increasingly urban, extreme weather events necessitate more durable building materials and the price of other infrastructure materials continues to rise.
Even construction professionals sometimes incorrectly use the terms cement and concrete interchangeably. Cement is actually an ingredient of concrete. It is the fine powder that, when mixed with water, sand, and gravel or crushed stone (fine and coarse aggregate), forms the rock-like mass known as concrete.
The Forms of Concrete
Concrete is produced in four basic forms, each with unique applications and properties.
- Ready-mixed concrete, far the most common form, accounts for nearly three-fourths of all concrete. It’s batched at local plants for delivery in the familiar trucks with revolving drums.
- Precast concrete products are cast in a factory setting. These products benefit from tight quality control achievable at a production plant. Precast products range from concrete, bricks and paving stones to bridge girders, structural components, and wall panels. Concrete masonry another type of manufactured concrete, may be best known for its conventional 8-by-8-by-16-inch block. Today’s masonry units can be molded into a wealth of shapes, configurations, colors, and textures to serve an infinite spectrum of building applications and architectural needs.
- Cement-based materials represent products that defy the label of “concrete,” yet share many of its qualities. Conventional materials in this category include mortar, grout, and terrazzo. soil-cement and roller-compacted concrete —”cousins” of concrete—are used for pavements and dams. Other products in this category include flowable fill and cement-treated bases.
- A new generation of advanced products incorporates fibers and special aggregate to create roofing tiles, shake shingles, lap siding, and countertops.
Resources:
- PCA – How Cement is Made
- The Constructor- Manufacture of Cement
- Cement Concrete Org.-Manufacturing of Portland Cement – Process and Materials
- Wikipedia- Portland Cement
- Madhav University Edu India- Portland Cement and Its Manufacturing
-
Sidney Mindess & J. Francis Young (1981): Concrete, Prentice-Hall, Inc., Englewood Cliffs, NJ, pp. 671.
-
Steve Kosmatka & William Panarese (1988): Design and Control of Concrete Mixes, Portland Cement Association, Skokie, Ill. pp. 205.
-
Michael Mamlouk & John Zaniewski (1999): Materials for Civil and Construction Engineers, Addison Wesley Longman, Inc.,
-
Penn State College of Engineering
Photo Gallery about Cement Factories, Cement Bags, and cement clinker
FOB Prices for Clinker, Grey Cement, and White Cement/ per MT
Cement Clinker
$19
Portland Cement Clinker-Type II
Status: Fresh, and High-Quality
Standard: ASTM C-150
Delivery: FOB-BIK Port
Payment Terms: TT
Grey Cement
$36
Grey Cement-Type II
Status: Fresh, and High-Quality
Standard: ASTM C 150- Type II
Delivery: FOB-BIK Port
Payment Terms: TT
White Cement
$61
Portland White Cement-52,5
Status: Fresh, and High-Quality
Standard: EN 197-1, 52,5
Delivery: FOB-BND Port
Payment Terms: TT
Gypsum
Rock
$8
GYPSUM rock
Status: High-Quality
Standard: Purity 90-95%
Delivery: FOB-BND Port
Payment Terms: TT
Order Procedures
CIF offer
Letter of Intent-LOI in the first level
For CIF offer, our sales team should determine all details such as the product cost, transit to the port of loading, loading to the vessel (or stuffing), customs duties, etc.
we require to obtain accurate information on the inquiry as Letter of Intent-LOI in the first level. Please mail us LOI to our Sales Team.
We hope you find detailed information about the answer to the question What is the manufacturing process of Portland Cement? in this article.
Datis Export Group supplies all types of Portland Cement (Grey, and White) and Cement Clinker. Our sales team will manage to export the Cement to any destination port for Bulk and Bagged containerized cargoes.
You can send us your cement inquiry by email to our sales office. Our branches will manage to supply and export the cement through the best-reputed cement factories in the region.