Which method is used for separation of wolframite ore?
(a) Roasting
(b) Calcination
(c) melting
(d) Electromagnetic

Hint:Wolframite is an ore of iron and tungsten.It is the main source of tungsten ,a strong and quite dense material with a high melting temperature used for electric filaments. It has magnetic properties. It is a series in tungsten ore minerals.

Complete step-by-step answer:-Wolframite ore can be represented as\[[FeW{{O}_{4}}]\]. It is present in tin stone as impurities. It has the same mass per unit volume as that of a tinstone. Because wolframite has a magnetic nature, it can be separated from tinstone using an electromagnetic separator. Tinstone is non magnetic.
-Electromagnetic separation is a process of removing magnetic materials from non magnetic materials, using electromagnets in which the materials travel along a conveyor, over a drum or into a revolving screen. It is a method to purify certain metals, ores, isolate metals and oils.
-Roasting is a process of heating of a sulphide ore at a high temperature in the presence of air. It is a metallurgical process involving gas-solid reaction at high temperatures and used to purify metal components. Roasting consists of oxidation, reduction, chlorination, sulfation and pyrohydrolysis reactions.
-Smelting is a process where metal is extracted from an ore by applying heat. Many metals are extracted from their ores using this method like silver, iron, copper and other base metals. This process uses heat and chemical reducing agents to decompose the ore, and driving off other elements and leaving only the metal base behind.
-Calcination is the process of heating ores at high temperature in the presence of air or oxygen. It is basically thermal decomposition of ores and other materials.

Thus, Wolframite ore is separated from tin stone ore by the process of electromagnetic separation and the correct answer to the question is option (d).

Note:The main difference between tinstone ore and wolframite ore is that tinstone ore is not magnetic while the latter is magnetic. Other processes are heating processes.