INTRODUCTION:
Extractive metallurgy is the study of the processes used in the separation and concentration of raw materials. The field is an applied science, covering all aspects of the physical and chemical processes used to produce mineral-containing and metallic materials, sometimes for direct use as a finished product, but more often in a form that requires further physical processing which is generally the subject of physical metallurgy, ceramics, and other disciplines within the broad field of materials science.
The field of extractive metallurgy encompasses many specialty sub-disciplines, each concerned with various physical and chemical processes that are steps in an overall process of producing a particular material. These specialties are generically grouped into the categories of mineral processing, hydrometallurgy, pyrometallurgy, and electrometallurgy. The distinctions among these groups of sub-disciplines within extractive metallurgy are far from clear, and many commercially important metallurgical processes involve considerable overlap.
The theoretical basis of extractive metallurgy is underpinned by the more general sciences of physics, chemistry, and geology. Additionally, the practice of extractive metallurgy nearly always involves contributions from other scientific fields such as analytical chemistry and mineralogy
The history of extraction metallurgy can be divided into two periods-the ancient period, when a small number of metals were known, and the recent period of about the last two centuries, when almost metals have become available commercially.
Many important metals are present in nature combined with sulfur as metal sulfides, these include cadmium, cobalt, copper, lead, nickel, zinc and gold group metals are associated with sulfides base metal ores. The extraction of metals from their ores has been an essential factor in the creation and development of our advanced level of civilization.
The first step in recovering metals from their ores is that of finding ore- bodies in which metal sulfides are present in a sufficient quantity and at a sufficient concentration, for mining to be economic.
The discovery of metals by depended on their being easily found, easily recognized ores and easily reduced from these ores. Extraction metallurgy is not confined to the production of a single metal from each ore. Metals and sometimes non- metals, present in ores in very small proportions may be concentrated into slag or flue dusts which are sometimes of great value.