The idea of froth floatation method came from a person X and this method is related to the process Y

Q: Why does the sulphide ore float while the gangue sinks?

This happens due to preferential wetting. Sulphide ores are wetted by pine oil, making them hydrophobic (water-repelling) and allowing them to rise with air bubbles. Gangue particles are wetted by water and sink.

Q: Who was the washerwoman mentioned in the history of this process?

The idea is widely attributed to Carrie Everson, a teacher and chemist, though popular metallurgical lore often romanticizes her as a "washerwoman" who noticed metallic dust floating in her laundry tubs.

Q: What is the difference between concentration and reduction?

Concentration is the physical process of removing unwanted impurities (gangue) from the ore. Reduction is the chemical process of converting the concentrated metal oxide/compound into pure metal.

Q: Can froth floatation be used for oxide ores?

Generally, no. Froth floatation is specifically highly effective for sulphide ores because of their natural affinity for oils. Oxide ores require different concentration methods like hydraulic washing or magnetic separation.

Q: What is the role of pine oil in this process?

Pine oil acts as a 'collector'. It coats the sulphide ore particles, increasing their non-wettability by water, which helps them attach to air bubbles and rise to the surface as froth.

Question

The idea of froth floatation method came from a person X and this method is related to the process Y of ores. X and Y, respectively, are

Options:

(A) fisher woman and concentration

(B) washer woman and concentration

(C) fisher man and reduction

(D) washer man and reduction

Sigma Percentile · Accepted Answer

The history of science is filled with serendipitous discoveries, but few are as charming and grounded in everyday life as the invention of the **froth floatation process**. This method, which revolutionized the metallurgical industry, didn't originate in a high-tech laboratory. Instead, it was born from the keen observation of a washerwoman!

### A Serendipitous Discovery

Imagine the late 19th century. A washerwoman (often identified in historical lore as Carrie Everson, though her actual profession was a teacher and chemist, the "washerwoman" myth persists in textbooks) was doing laundry. She noticed something peculiar while washing the heavily soiled, oily clothes of miners.

The metallic dust and ore particles embedded in the fabric didn't sink to the bottom of the wash tub like regular dirt. Instead, they clung to the soap suds and floated to the top! This simple, everyday observation sparked a massive industrial breakthrough. The oil in the clothes had preferentially wetted the metal sulphide particles, making them water-repellent (hydrophobic), while the regular dirt (gangue) was wetted by the water and sank. Thus, the person **X** in our question is the **washer woman**.

### The Magic of Froth Floatation

So, what exactly is this method used for? In metallurgy, before we can extract a pure metal from its ore, we must first get rid of the useless earthy impurities, known as gangue. This initial purification step is called the **concentration of the ore**.

The froth floatation method is specifically designed for the concentration of sulphide ores (like Zinc Blende, $ZnS$, or Galena, $PbS$). In a large tank, the crushed ore is mixed with water and a collector like pine oil. When air is vigorously blown through the mixture, the oil-coated sulphide particles attach to the air bubbles and rise to the surface, forming a rich froth that can be easily skimmed off. Meanwhile, the water-wetted gangue settles at the bottom.

### Concentration vs Reduction

It is crucial to distinguish between concentration and reduction. **Concentration** (our process **Y**) is merely the physical separation of the ore from the gangue. We haven't changed the chemical composition of the ore yet; $ZnS$ is still $ZnS$.

**Reduction**, on the other hand, is the subsequent chemical step where the concentrated ore is converted into the pure metal (for example, reducing $ZnO$ to $Zn$ using carbon). Since froth floatation only separates the physical components, it is strictly a concentration process.

By piecing together the historical anecdote and the metallurgical application, we can confidently conclude that the idea came from a **washer woman** and is used for the **concentration** of ores.

Animated Solution for Chemistry - Metallurgy: The idea of froth floatation method came from a person X and this method is related to the process Y of ores. X and Y, respectively, are

Select Answer:

Visualized Solution

$F r o t h F l o a t a t i o n S e t u p$

$P r e f er e n t ia l W e tt in g$

$T h e O r i g in (P er so n X)$

$P u r p ose o f t h e M e t h o d (P r ocess Y)$

$F ina l C o n c l u s i o n$

The Sigma Insight: Principles of Metallurgy and Extraction

A Serendipitous Discovery

The Magic of Froth Floatation

Concentration vs Reduction

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