Consider the following statements: Statement I: Studies indicate that carbon dioxide emissions from cement industry account for more than 5% of global carbon emissions. Statement II: Silica-bearing clay is mixed with limestone while manufacturing cement. Statement III: Limestone is converted into lime during clinker production for cement manufacturing. Which one of the following is correct in respect of the above statements?
Explanation
Cement manufacturing contributes significantly to global carbon emissions, mainly due to the chemical process involved in producing clinker.
Statement I: Cement industry emissions are estimated to be around 5-8% of global CO₂ emissions, making it a major source of greenhouse gases. Statement II: Silica-bearing clay is indeed mixed with limestone during cement making to provide essential minerals like silicon, aluminum, and iron needed for the final product. Statement III: During clinker production, limestone (calcium carbonate) is heated and converted into lime (calcium oxide), releasing CO₂ in the process. This calcination is the main source of carbon emissions in cement manufacturing.
Both Statements II and III are correct, but only Statement III directly explains the source of carbon emissions mentioned in Statement I.