Question

Shatter Index of the coke is a measure of its

• A. Reactivity
• B. Bulk density
• C. Strength
• D. Hardness

Hint:

Associate "Shatter Index" with "impact strength." The test simulates the rough handling coke undergoes when being charged into a blast furnace. A high index means strong coke, which is essential for furnace operation.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The Shatter Index is a critical physical property of metallurgical coke used in blast furnaces. It measures the coke's ability to withstand impact and handling without breaking into smaller pieces. In a blast furnace, coke must bear the weight of the iron ore and flux layers above it, so its mechanical strength is paramount.

Step 2: Detailed Explanation:
The Shatter test involves dropping a sample of coke of a specified size multiple times from a standard height (typically 2 meters). After the drops, the sample is sieved to determine the percentage of coke that remains above a certain screen size.
A high Shatter Index indicates that the coke is strong and resistant to breaking upon impact. This property is crucial because the generation of fine particles (fines) in the blast furnace can impede the flow of gases, reducing the efficiency of the smelting process.
Let's look at the options:

Reactivity: This relates to how easily the coke reacts with gases like \(CO_2\). It is a chemical property, not a mechanical one.

Bulk density: This is the mass of the coke per unit volume, including the voids between particles. While related to coke quality, it is not what the Shatter Index measures.

Hardness: This refers to the resistance of the coke to surface abrasion and scratching. It is often measured by a different test, like the Micum or IRSID test, which involves tumbling the coke in a drum. While related to overall durability, the Shatter Index specifically measures resistance to impact breakage, which is a key aspect of its overall mechanical strength.

Strength: This is the general term for the ability to resist mechanical stress and strain. The Shatter Index is a direct measure of the coke's impact strength.

Step 3: Final Answer:
The Shatter Index is a standardized test to quantify the impact strength of coke, which is its ability to resist shattering during handling and in the blast furnace. Therefore, it is a measure of its strength.