Cement Processes Presentation, Study Guides, Projects, Research of Chemical Processes

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CEMENT

Cement is mostly used as a binding agent in concrete, which is used to build houses, roads, schools, hospitals, dams, ports, and other types of buildings, as well as floors, stairs, driveways, pool decks, and other things like tables, sculptures, and bookcases.

HISTORY OF CEMENT

▪ Ancient Greece and Rome – the materials used were lime and a volcanic ash. (Pozzolana cement) ▪ 1756 - hydraulic lime was first developed by John Smeaton ▪ 1800 - cement rock ▪ 1824 – portland cement by Joseph Aspdin ▪ 20 th Century – manufacture of cement spread worldwide ▪ 2019 – China and India became the world leaders in cement production followed by Vietnam, United States, and Egypt.

Composition of

Cement

• Limestone
• Clay
• Gypsum
• Pozzolans

Clay is another essential ingredient in cement and is used to provide the cement with its chemical properties. Clay is a source of aluminum oxide (Al 2 O 3 ) and silica (SiO 2 ), which are vital to the chemical reactions that occur during cement production.

Gypsum (CaSO 4 • 2 H 2 O) is a mineral that is added to cement to regulate the setting time. It works by reducing the rate at which the cement solidifies, giving the cement additional time to be put into place before it hardens.

TYPES OF CEMENT

• ORDINARY PORTLAND

CEMENT

Composition

• Argillaceous or silicates of alumina (clay and shale).
• Calcareous or calcium carbonate (limestone, chalk, and marl) Uses
• It is used for general construction purposes.
• It is also used in most of the masonry works.

TYPES OF

CEMENT

▪ PORTLAND POZZOLANA CEMENT Composition

• OPC clinker
• Gypsum
• Pozzolanic Materials (Fly ash, volcanic ash, and Calcined clay or silica fumes.) Uses - hydraulic structures, marine structures, construction near the seashore, dam construction, etc. - pre-stressed and post-tensioned concrete members - decorative and art structures - manufacture of precast sewage pipes

TYPES OF

CEMENT

▪ SULPHATE RESISTING CEMENT Composition Higher in^ tetracalcium^ aluminoferrite^ (C4AF), and lower in tricalcium aluminate (C3A) than regular cement. Uses Construction in contact with soils or groundwater having more than 0.2% or 0.3 % g/l sulfate salts respectively. Concrete surfaces subjected to alternate wetting and drying such as bridge piers, concrete surface in the tidal zone, apron, Building near the seacoast. Effluent treatment plans, Chimney, Chemical industries, water storage, sumps, drainage works, Cooling towers, Coastal protective works such as sea walls, breakwaters, tetrapods, etc.

TYPES OF

CEMENT

▪ HIGH ALUMINA CEMENT Composition

• manufactured by fusing a mixture of limestone and bauxite (usually containing iron oxide, silica, magnesia, and other impurities). Uses
• It is used where concrete structures are subjected to high temperatures like workshops, refractory, foundries, etc.
• It also used where the concrete is subjected to frost and acidic action.

DRY PROCESS OF CEMENT MANUFACTURE Crushing & Storage Mixing & Storage Burning & Cooling Grinding

FLOWCHART OF

THE DRY

PROCESS

MANUFACTURE

ADVANTAGES OF DRY

PROCESS MANUFACTURE

Labour productivity is increased. Low capital is required. Fuel consumption is reduced. Modern-day technology can help with the proper mixing of materials in dry form.

DISADVANTAGES OF DRY PROCESS MANUFACTURE

• The dry process of cement manufacture is a slow process.
• The cement produced is of inferior quality to that produced by the wet process.