Tin stone is contaminated with Wolframite. Which one of the following methods can be employed to dress the tin stone ore? (a) Electromagnetic separation (b) Levigation (c) Roasting (d) Floatation process

One of the cornerstone techniques in mineral processing is electromagnetic separation. This method exploits the magnetic properties of certain minerals to facilitate their separation from a mixture with non-magnetic substances.

Here's how it works: when a mixture containing both magnetic and non-magnetic materials is subjected to a magnetic field, the magnetic components align with the field lines and can be diverted away from the non-magnetic parts. This is particularly useful in the mining industry where the separation of valuable ore from less useful material is crucial to efficient processing.

Considering our exercise, tin stone, contaminated with wolframite, electromagnetic separation presents an elegant and efficient solution due to the distinct magnetic characteristics of wolframite. While cassiterite, the mineral form of tin oxide making up tin stone, remains unaffected by the magnetic field, wolframite is attracted to it and can thus be separated.

This targeted separation ensures that the non-magnetic tin stone can be extracted without the unintended inclusion of wolframite, leading to a higher purity of the tin concentrate.

Cassiterite, an ore of tin, is a vital mineral that plays a significant role in the manufacturing of metallic tin. Scientifically known as tin oxide, its chemical formula is SnO2. Typically appearing in opaque granular formations, cassiterite is distinguished by a high density and an excellent hardness which prevents it from being easily abraded.

From a mineral processing perspective, cassiterite presents certain challenges due to its physical and chemical characteristics. It is chemically inert and has non-magnetic properties, which means that specific ore dressing methods, like electromagnetic separation, are unsuitable as a direct means of concentrating cassiterite itself. However, these attributes make cassiterite easily distinguishable from other minerals like wolframite, which is beneficial for ore dressing.

Moreover, cassiterite is often found in stream sediments because its resistance to weathering allows it to be liberated from the host rock and transported to new locales. Consequently, placer deposits can become a significant source of tin.

Wolframite is another important mineral which represents a major source of the metal tungsten, a material with a myriad of industrial applications due to its high melting point and density. In terms of composition, it is an iron manganese tungstate with the formula (Fe,Mn)WO4. The mineral often occurs in quartz veins and pegmatites, as well as in metamorphic rocks and as a secondary mineral in granites.

Unlike cassiterite, one of the distinguishing features of wolframite is its magnetic property, which allows for the application of electromagnetic separation as a method of ore dressing. When ground ore containing wolframite is introduced into a magnetic field, wolframite particles are pulled by the magnetic force whereas non-magnetic materials like cassiterite remain unaffected.

This characteristic is exploited in mineral processing to extract wolframite from mixed ores, enhancing not only the efficiency but also the environmental friendliness of the mining operation, as the use of water or chemicals can be reduced or eliminated. Moreover, the reduction of manual sorting and mechanized handling can directly translate to economic savings and improved ore quality.