The operation of removal of impurities of clay adhering to iron ore is known as
⛏️ Understanding Ore Preparation
Before valuable metals can be extracted from the earth, the raw material, or "ore," must be processed. Ore as mined is a mixture of the desired mineral and unwanted waste material (like rock, sand, and clay) called "gangue". The initial step involves mechanically separating the valuable minerals from this gangue. This concentration of the ore is a critical stage in metallurgy.
🔬 Detailed Analysis of the Options
C. dressing
This is the correct answer. "Ore dressing" (also known as mineral processing or beneficiation) is the specific technical term for the mechanical separation of valuable minerals from gangue. This involves physical processes like crushing, grinding, washing, and screening. Washing the iron ore would remove the adhering clay, which perfectly matches the description.
A. calcination
This is incorrect. Calcination is a high-temperature heating process that causes chemical decomposition, such as driving off water or carbon dioxide. It changes the ore's chemical structure, rather than just mechanically removing an impurity like clay.
D. refining
This is incorrect. Refining is a much later stage in metal production. It is the process of purifying the crude metal *after* it has already been extracted from its ore (e.g., after smelting). Its purpose is to achieve a very high degree of purity in the final metal product.
B. purification
This is incorrect because it is too general. While dressing is a form of purification, "dressing" is the specific industry term for the initial mechanical concentration of ore. In technical questions, the most specific and correct term is always preferred.
📊 Summary: Material Processing Stages
| Term | Process Type | Purpose & Stage |
|---|---|---|
| Dressing | Mechanical | Initial Stage: Separate ore from waste (gangue). |
| Calcination | Thermal/Chemical | Intermediate Stage: Chemically alter the ore by heating. |
| Refining | Chemical/Electrolytic | Final Stage: Purify the extracted metal. |
💡 Study Tips
- Remember the Order: The typical metallurgical process flows like this: 1. Mining → 2. Dressing → 3. Extraction (Smelting) → 4. Refining.
- Dressing = "Getting Ready": Think of ore dressing as "getting the ore ready" for the main process by cleaning off the dirt and waste rock.
- Refining = "Fine-Tuning": Think of refining as the final "fine-tuning" step to get a very pure metal.
- Associate Calcination with Heat: Remember that calcination always involves high temperatures to induce a chemical change.