UPSC Prelims 2020 Question:

Steel slag can be the material for which of the following?

1. Construction of base road 
2. Improvement of agricultural soil 
3. Production of cement
   
   

Select the correct answer using the code given below: 

Explanation:

• Steel slag is a byproduct of steel production. It is produced in steel-making furnaces during the separation of molten steel from impurities. The slag is formed as a molten liquid melt and is a complex solution of silicates and oxides that solidifies when cooled.
  
  
• It is used in a variety of activities, including road construction. These are the preferred aggregates because they harden well, allowing for a thinner layer of pavement than crushed stone aggregates. Slag is also extremely durable, withstanding both weather and wear. So, point 1 is correct.
  
  
• It favours the increase of pH and the availability of nutrients such as Calcium, Magnesium, and Silicon in the soil, which leads to an increase in the absorption of these elements by the plant, favouring crop growth and yield. So, point 2 is correct.
  
  
• Steel-slag can be used to produce energy-saving cement by co-grinding with cement clinker and blast furnace slag. It can replace Portland cement in various applications and is especially suitable for projects where a low heat of hydration is required.  So, point 3 is correct.
  
  

Therefore, option (4) is the correct answer.

Relevance: The steel ministry requested the agriculture ministry to look into the scope of using steel slags in agricultural soils.

Subject: Geography | Mineral Resources