Designed for metallurgical operators, technicians, and early-career engineers, this course provides a comprehensive examination of impurity and gas control during primary steelmaking. It covers the chemical, thermodynamic, and kinetic principles governing the removal of oxygen, carbon, sulphur, phosphorus, hydrogen, and nitrogen. Learners will explore industrial deoxidation, decarburisation, desulphurisation, and degassing processes, with a strong focus on process optimization, material interactions, and refining strategies. Through simulation and scenario-based activities, participants will develop the competence to evaluate slag-metal reactions, control gas levels, and ensure steel quality meets specification standards. This course is part of the Advanced Metallurgy Fundamentals series.