Difficulty: Easy
Correct Answer: Silicon, sulphur, phosphorus, and manganese
Explanation:
Introduction / Context:
Iron ores (hematite, magnetite, limonite, etc.) contain gangue and minor elements that affect smelting, slag chemistry, and steel quality. Recognizing likely impurities guides beneficiation and flux selection.
Given Data / Assumptions:
Concept / Approach:
Common ore impurities are silicon (as silica), sulphur, phosphorus, and manganese. Carbon is not an inherent impurity of the ore matrix; carbon enters later via coke in the furnace. Therefore, the grouped option listing Si, S, P, and Mn best represents practical metallurgy.
Step-by-Step Solution:
List common elements in ore and gangue: Si, S, P, Mn.Exclude carbon as it is not a natural ore constituent in significant amounts.Choose the option that groups Si, S, P, Mn together.
Verification / Alternative check:
Typical ore analyses in textbooks show silica as the major gangue with minor S, P, and Mn—targets for slagging and refining.
Why Other Options Are Wrong:
Only carbon/phosphorus/silicon are incomplete. None ignores widely documented impurities.
Common Pitfalls:
Confusing ore impurities with blast furnace charge additions (coke carbon); conflating steel alloying elements with ore composition.
Final Answer:
Silicon, sulphur, phosphorus, and manganese
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