UPSC Civil Services 2020 Prelims General Studies Paper I

Explanation

Steel slag, a by-product of steel making, is produced during the separation of the molten steel from impurities in steel-making furnaces.

● Because of its hydraulic property and the large bearing capacity it can provide, steelmaking slag is used as a road base course material. Hence Statement 1 is correct.

● Use of metallurgical solid wastes such as steel slag, in agricultural activity, has become very important to contribute to reducing the accumulation of such wastes in the environment and to increase crop production. Application of slags to soil chemical attributes as elevation of pH and neutralization of Al3+ toxic in acid soils and increase nutrient content as phosphorus, calcium, magnesium, some micronutrients, and silicon. Hence Statement 2 is correct.

● Steel-slag can be used to produce energy-saving cement by co-grinding with OPC clinker and blast furnace slag. Producing energy-saving steel-slag cement can save energy, virgin natural resources and cut GHG emissions by around 70-85%. Hence Statement 3 is correct.