Cement clinker

Composition and preparation: Portland clinker consists of four minerals: alite, belite, tricalcium aluminate, and calcium aluminoferrite. Raw materials for clinker include limestone mixed with clay or silicon dioxide. Second raw materials depend on limestone purity and can include clay, shale, sand, iron ore, bauxite, fly ash, and slag. Production involves heating raw materials in a rotary kiln at high temperature. Special cements require limiting tricalcium aluminate formation. Uses: Portland cement clinker is ground to a fine powder and used as a binder in various cement products. Addition of gypsum is necessary to prevent flash setting of tricalcium aluminate. Clinker is used in different types of cement like Ordinary Portland Cement (OPC) and pozzolanic cements. Clinker is an ingredient in artificial rock called pulhamite for landscaping. Clinker can be stored for months without quality loss and is traded internationally. Clinker grinding aids: Gypsum is added to prevent flash setting and aid in grinding by preventing agglomeration. Organic compounds like triethanolamine are used as grinding aids. Other additives such as ethylene glycol, oleic acid, and dodecylbenzene sulfonate are sometimes used. Clinker minerals hydration: Clinker minerals react with water to form hydrates and set as concrete. Calcium silicate hydrates are the main glue components in concrete. Initial setting occurs in the first 28 days, and hydration requires water for hardening. Desiccation must be prevented to avoid cracks in young concrete. Curing compounds can be used to create a waterimpermeable coating on concrete surfaces. Contribution to global warming: Cement production accounted for about 8% of global carbon emissions in 2018. Most emissions are generated during the clinker manufacturing process.