Cement is Sturdy, Strong and Durable

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1 Welcome to Cementa!

2 Cement is Sturdy, Strong and Durable THE FINE-GRAINED POWDER CALLED CEMENT Cement is a fine-grained powder made out of limestone and clay minerals. It is used all over the world, and in terms of volume is used more than any other industrial product. CEMENT IS USED TO PRODUCE CONCRETE When cement is mixed with water and a filler of gravel and stone it is called concrete. Formability, strength and durability are the main characteristics of concrete, which also has a very good technical and economic lifetime. Different types of concrete are consequently our most important building material, both in small homes and large skyscrapers, in segments of sidewalk or in sewage pipes, in tall bridge pillars and in long tunnels, and in power stations and water towers. LONG BEFORE THE ANCIENT GREEKS Use of concrete as a building material has developed over thousands of years. The Phoenicians were the first to discover that a strong glue is produced when calcined limestone is mixed with water. This discovery was made in ancient Jerusalem about 1,000 BC. Many impressive concrete constructions were built during the days of the Roman Empire. In the Mediterranean area we can still see aqueducts, sewage systems and amphitheatres that were built about 2,000 years ago. After the collapse of the Roman Empire, the technique for manufacturing cement was forgotten. It wasn t until the mid-1800s that concrete became the most widely used building material of modern times. At that time, a new manufacturing method for industrial cement, which was produced by burning a mixture of limestone and clay at an extremely high temperature, was developed in England. SWEDEN AND CEMENT Sweden has a long tradition of using cement. Swedish construction techniques and architectural 2

3 CEMENTA AND THE ENVIRONMENT Cementa has chosen to work according to the ISO environmental management system, a framework for controlling, monitoring and evaluating environmental work. Cementa s large environmental improvement programme has, amongst other things, resulted in a 90% reduction in emissions of nitrous oxides and sulphur. Cementa s work to achieve continual environmental improvement also includes the reduction of dependence on fossil fuels by replacing them with equivalent alternative fuels. These fuels have a constant energy value and standard quality, and are made by special recycling companies. designs using concrete building materials have always been considered very advanced from an international standpoint. Skånska Cement Ltd. was founded in 1871, and one year later the first cement plant in Sweden was opened. It was located in Lomma, outside the city of Malmö, and was the basis for today s Cementa. Since then, there have been a total of 14 cement plants in Sweden. Three remain today. They are located at Slite on the Baltic Sea island of Gotland, at Skövde in Västergötland County (Southwest Sweden), and at Degerhamn on the Baltic Sea island of Öland. CEMENTA TODAY With knowledge and experience gained from over a century in operation, Cementa is today a modern, high-tech company. We invest large resources in the development of new products and markets. A few examples of our product development are highperformance, ultra-strong concrete, rapid-hardening concrete, fibre concrete and special concretes for enhancing the durability of constructions. Approximately half of Cementa s total production is exported, and is supplied from the Slite plant to, among other places, the United States and Africa. CEMENTA AND CONCRETE The environmental image of concrete has markedly improved in recent years. This has been achieved through active work on quality and strong environmental measures within Cementa s areas of activity. Research and development work on the qualities and uses of concrete are carried out by Cementa s Marketing and Research and Development Department and in co-operation with trade organisations, cement production companies, and the technical universities in Sweden. Issues that deal with the environmental impacts of different construction materials, comfortable housing, and energy and health are discussed as much today as issues that deal with technology and economics. Therefore, to show that concrete sufficiently meets the requirements set by today s society, Cementa has for many years had the motto healthy building with concrete. 3

4 CEMENT PRODUCTION FLOWCHART The numbers refer to the different stages of production 1. Ouarrying. Limestone and marl are needed to produce cement. 2. Crushing. The rock is crushed to a maximum size of 80 mm. 3. Mixing storage piles. These stockpiles act as a buffer stock for the raw mill and as a mixing station, where the raw material is mixed to achieve the best possible uniform quality. 4. Raw mill. The rock is ground into a fine powder with particles less than 0.09 mm in size. 5. Electrostatic precipitator. Dust in the flue gases released by the kiln are removed in a highly efficient electrostatic precipitator. 6. Sulphur removal facility. The flue gases are washed with the help of ground limestone and water in a so-called wet scrubber. The resulting waste is gypsum, which is returned to the process. 7. Raw meal silos. These are for the intermediate storage of the ground limestone. 8. Cyclone tower with precalcination. Precalcination of the raw meal occurs when the calcium carbonate is split into calcium oxide and carbon dioxide. 9. Kiln. The kiln, which is between 60 and 80 meters long, consists of a long, rotating steel pipe. The material is conveyed slowly down to the burner and is converted to clinker. The temperature of the burner is 1,450 C. The heat comes from coal and alternative fuels. 10. By-pass filter. A too high alkali content negatively affects durability of cement. After the cyclone tower, the material therefore passes through a filter to remove the alkalis in a condensation process. 11. Clinker cooler. Here, the clinker is air-cooled. 12. Electrostatic precipitator. The gases from the cooler are cleaned in these filters. 13. Clinker silos. This is where the finished clinker is stored. 14. Gypsum and additives storage. Gypsum and additives are stored here, to be ground together with the clinker to, among other things, adjust the bonding time of the cement. 15. Cement mills. The clinker is ground with gypsum and if necessary, limestone, to produce the finished cement. 16. Cement silos and unloading. From the intermediate storage in silos, the finished cement is loaded using a closed system onto ships or trucks. 4

5 From Limestone to Cement Cement is made from a mixture of limestone and clay minerals that are crushed and ground into a dry powder. The powder, called raw meal, is fired in huge rotary kilns, where the internal temperature is about 1,400 C. During the firing process, the raw meal is converted into a number of minerals that are as hard as glass and similar to porcelain. The fired material is called clinker, which is ground, together with some gypsum, into a grey powder cement. The level of chromate in all the types of cement produced by Cementa has been reduced in order to protect the health of concrete workers. CEMENTA S SLITE PLANT Limestone was exported from the Baltic Sea Island of Gotland as far back as the 11th century. Over the years, North Gotland became the island s principal area for limestone quarrying. Limestone was easily available there, the harbours were good, and there was an abundance of fuel. April 4, 1919 was an important day in the contemporary history of Slite. On that date the first rotary cement kiln was started up in what was then considered to be an ultra-modern plant. Since then, there has been continued, uninterrupted production. Today, Cementa s plant on Gotland is one of the most modern and energy efficient cement plants, where computers control and supervise most of the production process. The plant produces construction cement, rapid-hardening cement and different types of cement for export. To guarantee the quality of all the cement produced, samples are analysed during the entire production process using advanced control systems. The cement plant has been improved on a continual basis in order to reduce its environmental impact. Most conveyor lines are completely enclosed to reduce dust emissions and noise, and there are advanced purification facilities to deal with emissions and flue gases. Production of cement requires a high temperature and thus large of amounts of fuel. The main fuel sources are coal and other fossil fuels, but in- creased environmental awareness, increased environmental requirements, and increased fuel costs have resulted in an ever greater use of alternative fuels. Conservation of raw materials and energy is an important part of all environmental work. The Slite plant manufactures approximately 2 million metric tons of cement per year and accounts for more than 75% of all the cement produced in Sweden. The plant has about 250 employees. 5

6 CEMENTA S SKÖVDE PLANT In the hills of Västergötland, lime burning has been a tradition since the Middle Ages. This activity was expanded by the Gullhögen s Bruk Company in 1924, with the establishment of a small cement plant in the town of Skövde. The first rotary kiln was started up in the 1930s and the plant was expanded considerably during the 1950s and 1960s. Cementa purchased Gullhögens Bruk in The Skövde facility produces construction and rapid-hardening cement, and its main area of distribution is the interior of Western Sweden. About 65 people work at the Skövde facility, and the capacity of the kiln is about 600,000 metric tons per year. CEMENTA S DEGERHAMN PLANT One of the first cement plants in Sweden was built on the Baltic Sea Island of Öland, where production began at Öland s Cement Ltd. in Today, the Degerhamn plant focuses on manufacturing a special type of cement for heavy concrete constructions, that has a very low heat development. This cement is particularly suited for use in bridges and heavy concrete foundations that are exposed to severe stresses from the environment, such as from frost, salts used to melt snow and ice, and sea water. The first tests with the new cement were conducted in 1983 and this special product has been used in many large constructions around Sweden ever since. One of the biggest projects where it was used is the Öresund Link Bridge between Sweden and Denmark. The plant on Öland is also equipped with an automated system for packing cement in 25 kilo bags. The facility also has a depot for storing cement from the Slite plant and a special production line for extra fine-grained injection cement. About 75 people work at the Degerhamn plant, and its capacity is 250,000 metric tons of cement per year. KRISTINEHAMN Cementa s facility for production and storage of additives used in concrete production is in Kristinehamn. 6

7 Quality Control Cementa s laboratory, Cementa Research, is located on the same site as the Slite plant on Gotland. There, in well-equipped facilities, about 50 people work on advanced research, development and quality control of different types of mineral based construction materials, such as cement, mortar, concrete and gypsum. For example, cement is checked for development of strength, bonding time, specific surface, chemical composition, consistency properties, and manageability of the powder. The same checks are used to control the quality of lime and limestone, as well as raw materials such as sand, gypsum, coal, petcoke, and plastic and rubber fuel supplements. Since the lifetime of construction material has a crucial effect on economics and the environment, Cementa Research prioritises research on durability of construction materials, particularly within the area of concrete. Cementa Research is certified by the Swedish Board for Accreditation and Conformity Assessment (SWEDAC), which has assessed and approved the company s impartiality, proficiency, equipment and methods. A total of over 100 methods are approved, including our own as well as Swedish and international standards. Eighteen Depots around the Country Cement is a perishable commodity and strict requirements are imposed in order to distribute the goods in a rapid and environmentally-friendly manner. We have therefore developed a transportation system with vessels and depots throughout Sweden. The depots are strategically located in 18 places around the country. From the depots the cement is further transported by train or special bulk-carrying trucks. The shipments are made in totally closed systems, which means that the management is practically dust-free. Three custom-built ships are used to transport cement to the Swedish depots as well as for export out of the country. Our transports by ship account for close to 8% of the total Swedish coastal shipping. The vessels Sunnanvik, Östanvik and Västanvik employ a crew which totals about 65 people. 7

8 Cementa AB is part of the international construction materials group of companies, HeidelbergCement. The group of companies has an annual turnover of slightly more than 60 billion SEK and has about 37,500 employees in about 50 countries. EIDELBERGCEMENTGroup Cementa AB, P.O. Box 144, SE Danderyd, Sweden. Phone Fax danderyd@cementa.se Website: