Question

Galena ore is concentrated by (a) gravity separation (b) froth flotation process (c) magnetic separation (d) roasting

Short answer

Galena ore is concentrated by froth flotation process.

Step-by-step solution

Understanding Galena Ore

Galena is a natural mineral form of lead(II) sulfide and is the most important lead ore. We first need to understand the composition and properties of galena to determine the appropriate method for its concentration.

Identifying the Physical and Chemical Properties

Galena is heavy and primarily composed of lead sulfide (PbS), which is not magnetic. This property helps us eliminate magnetic separation as a possible method for concentration, as it is best suited for magnetic ores.

Analyzing the Given Methods

Next, we analyze the remaining methods: - Gravity separation utilizes differences in density, which could potentially work, but is not the best method for galena. - Froth flotation leverages differences in surface properties between sulfide minerals and impurities. - Roasting is a thermal process and not a concentration method.

Selecting the Appropriate Method

The froth flotation process is particularly effective for sulfide ores like galena because it exploits the different wetting properties of the ore and waste. This method effectively separates the lead sulfide in galena from impurities.

Key concepts

Galena Ore Processing

Galena ore processing is crucial in extracting lead from raw materials. Galena is a natural mineral form of lead(II) sulfide and serves as the primary source of lead. The processing begins with identifying the ore's properties, primarily focusing on its composition and physical characteristics.

To effectively process galena ore, it is essential to consider that it is composed mainly of lead sulfide ({PbS}). This knowledge helps in evaluating different concentration methods. The aim is to separate the valuable lead sulfide from unwanted impurities. The most effective method to achieve this is the froth flotation process.

During the froth flotation process, ground galena ore is mixed with water to form a slurry. Adding specific chemicals causes some particles to become hydrophobic, meaning they repel water. Air is blown through the mixture, forming bubbles that lead sulfide particles stick to, allowing them to float to the surface. This separates them from the non-valuable material, which sinks. This refined concentrate is then collected for further processing.

Sulfide Ore Concentration

Sulfide ore concentration is vital in extracting metals efficiently. The froth flotation process is the primary technique used to concentrate sulfide ores like galena.

This method capitalizes on the contrasting surface properties of sulfide minerals and the waste rock. In the case of galena, the surface of the lead sulfide minerals is treated to make them hydrophobic. This treatment makes these particles selectively adhere to the bubbles introduced to the slurry. As they rise with the bubbles, a concentrated foam forms at the top.

Significantly, froth flotation enables the separation of the sulfide ore without much interference from the actual mineral composition making it versatile. It is also efficient and cost-effective compared to other methods. By focusing on the surface properties and not the density or magnetic nature of the ore, froth flotation provides a robust solution for concentrating sulfide ores.

Lead(II) Sulfide Properties

Lead(II) sulfide properties are critical to understanding how galena ore is processed. Lead(II) sulfide is the chemical compound {PbS}, which is integral to the mineral galena. Understanding the properties of lead(II) sulfide helps illuminate why certain concentration processes are preferred over others.

Lead(II) sulfide is known for its heavy and non-magnetic characteristics. One of the defining traits of {PbS} is its ability to become hydrophobic when treated with certain chemicals. This transformation is the cornerstone of the froth flotation process. By altering its wetting properties, {PbS} can be effectively separated from other non-valuable materials in the ore.

Furthermore, the high density of lead(II) sulfide compared to surrounding materials aids in enhancing the separation process during concentration. These properties underscore the choice of froth flotation as an optimal method for galena ore concentration, ensuring that lead is extracted efficiently from its sulfide mineral form.