Economic and Mineral Processing Techniques

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Questions and Answers

What is the primary influence of macroscopic properties on ore extraction?

They influence the design of the mining operation. (correct)

They determine the chemical composition of the ore.

They dictate the market price of the extracted metals.

They establish the micro-structural characteristics of the ores.

Which of the following is NOT considered a microscopic property of ore?

The mineral phases that occur.

The physical-chemical properties of the mineral phases.

The transportation logistics of ore. (correct)

The volumes and mass fractions of minerals.

What motivates the rise of secondary source reclamation in Europe?

Increased global demand for metals.

The drive towards a circular economy. (correct)

Decreasing availability of natural ores.

Technological advancements in mining.

Which extraction methods are utilized for upgrading and refining ores?

Hydrometallurgy and pyrometallurgy. Signup and view all the answers

How do micro-structural characteristics of ores affect their processing?

They influence the physical- and chemical processing methods. Signup and view all the answers

Which aspect contributes most to the industrial costs of a processing plant?

Costs associated with the ore itself. Signup and view all the answers

What key characteristic of ores helps determine economic viability for extraction?

The composition and mass fractions of the mineral phases. Signup and view all the answers

Which is a consequence of macro- and microscopic properties analysis of ores?

Enhanced extraction technique designs. Signup and view all the answers

What is the primary challenge when valuable minerals are finely spaced in the ore matrix?

Milling the ore is economically unfeasible until complete liberation. Signup and view all the answers

Why is mineral liberation easier when minerals occur as a shell structure or coarse grains?

Size reduction methods are more effective. Signup and view all the answers

What effect do multi-phase particles (middlings) have on mineral refinement processes?

They can dilute valuable minerals or lead to loss with refuse. Signup and view all the answers

What influences the quality of mineral separation during the processing operation?

Mineral liberation and equipment design. Signup and view all the answers

What is a necessary characteristic for optimal mineral separation?

Perfect mineral liberation and effective machine operation. Signup and view all the answers

What role does the texture of minerals play in the refinement process?

Different textures affect how minerals behave, even with similar mineral phases. Signup and view all the answers

How does the presence of intergrowths in minerals affect refining?

They lead to complex multi-phase particles after milling. Signup and view all the answers

What is the overall objective of mineral processing?

To separate different mineral types effectively. Signup and view all the answers

What is the ratio of concentration?

The mass of the feed divided by the mass of the concentrate Signup and view all the answers

Which indicator combines recovery and grade to assess metallurgical efficiency?

Separation efficiency Signup and view all the answers

How is separation efficiency mathematically expressed?

Separation efficiency = Recovery of mineral - Recovery of gangue Signup and view all the answers

In terms of flow rates, the recovery of mineral can be expressed as which of the following?

$(C \times c_m) / (F \times f_m)$ Signup and view all the answers

What does gangue refer to in the context of mineral processing?

Non-economic minerals present in the feed Signup and view all the answers

When calculating recovery of gangue, which formula is used?

$(C \times c_g) / (F \times f_g)$ Signup and view all the answers

Why is improved liberation of feed material necessary?

To obtain a larger proportion of mineral without diluting the concentrate Signup and view all the answers

Which of the following conditions would lead to higher recovery at a fixed target grade?

Improved liberation of the feed material Signup and view all the answers

What does the variable x represent in the context of slurry calculations?

The percentage solids by weight in the slurry Signup and view all the answers

How is the volume of a phase calculated according to the provided equations?

By multiplying the mass of the phase by its density Signup and view all the answers

Which of the following equations represents the relationship defined for the total volume of the slurry?

$V_{s} = V_{d} + V_{l}$ Signup and view all the answers

What is the formula for calculating the percentage of solids by weight, x, in a slurry?

$x = \frac{m_{o}}{m_{s}} \times 100$ Signup and view all the answers

Which relationship is used to express the volume of slurry in terms of mass and densities of the respective phases?

$V_{s} = \frac{x}{100} \cdot \frac{m_{s}}{\rho_{o}} + \frac{1 - x/100}{\rho_{l}}$ Signup and view all the answers

What assumption is typically made about the density of the liquid phase in slurries?

It is often approximated as 1000 kg/m³. Signup and view all the answers

When calculating x, which of the following statements is true regarding the relationship between densities of phases?

The equation is derived assuming volume additivity. Signup and view all the answers

In rearranging the equation for x, what is the significance of the term $ ho_{l} - ho_{o}$?

It is the difference in density affecting the percentage calculation. Signup and view all the answers

What factors influence the calculation of the % solids by weight in a slurry?

The mass of dry solids and the densities of both phases. Signup and view all the answers

What is the significance of the zero value in the formula for x?

It indicates a fully liquid phase with no solids present. Signup and view all the answers

What does the term 'grade' refer to in the context of mineral processing?

The content of the marketable end product in the material Signup and view all the answers

What is the recovery rate expressed as in mineral processing?

The percentage of the total metal contained in the ore that is retrieved in the concentrate Signup and view all the answers

How is the mass of the desired species in the concentrate calculated?

By multiplying the mass flow rate of the concentrate by its grade Signup and view all the answers

In the context of metallic ores, what does a recovery rate of 90% imply?

10% of the metal content is lost to tailings Signup and view all the answers

What is the purpose of calculating the recovery of a mineral separation process?

To measure the efficiency of the mineral concentration Signup and view all the answers

Which formula correctly represents the recovery of a species in mineral processing?

$R = \frac{M_{i} \text{ in concentrate}}{M_{i} \text{ in feed}} \times 100$ Signup and view all the answers

What does tailings refer to in mineral processing?

The portion of ore that contains gangue minerals Signup and view all the answers

What is the significance of the grade of the feed material?

It indicates the value of the marketable product in the ore Signup and view all the answers

What does a higher grade in the concentrate indicate?

Greater relative abundance of the desired mineral Signup and view all the answers

If the grade of a feed material is 5% and its mass flow rate is 200 tons, what is the mass of the desired species in the feed?

50 tons Signup and view all the answers

Study Notes

Economic Viability of Ore Extraction

Macroscopic properties influence ore extraction methods, impacting mine design and raw material costs.
Microscopic ore properties are critical for determining economic and technical feasibility of refinement processes.
Important microscopic properties include mineral phases, composition, volume, mass fractions, grain sizes, physical-chemical properties, shape, and microstructure.

Mineral Liberation and Processing

Microstructure influences physical and chemical processing methods.
Physical and chemical techniques (hydrometallurgy and pyrometallurgy) are used to extract, upgrade, and refine valuable species.
Mineral liberation by size reduction is more economical when valuable minerals occur as coarse grains or as a shell structure around the ore matrix.
Finely spaced minerals in a gangue matrix are difficult to separate.
Multi-phase (multi-mineral) grains form during crushing and milling, leading to middlings (multi-phase particles).

Problems with Middlings

Multi-phase particles with mainly valuable minerals dilute the concentrate with worthless gangue.
Multi-phase particles with mainly gangue lead to loss of valuable minerals in the refuse stream.

Mineral Separation Efficiency

Mineral separation aims to produce a concentrate with a higher relative abundance of the desired mineral and tailings with a higher relative abundance of gangue.
Performance criteria include grade (assay), recovery, and separation efficiency.
Grade refers to the content of the marketable end product in the material.
Recovery is the percentage of the total metal or mineral in the feed that is recovered in the concentrate.

Factors affecting Recovery and Grade

Higher recovery at a fixed target grade or higher grade at a fixed target recovery requires improved liberation of the feed material.
Ratio of concentration is the ratio of the mass of feed to the mass of concentrate.
Enrichment ratio is the ratio of the grade of the concentrate to the grade of the feed.
Separation efficiency combines recovery and grade to define metallurgical efficiency.
Separation efficiency is calculated as the recovery of the mineral of interest minus the recovery of gangue to the concentrate.

% Solids by Weight Calculation

Density of the slurry, dry solids, and the volume additivity assumption are used to calculate the percentage solids by weight (x).
The formula for x is derived using volume additivity, mass, and density of the slurry and phases.
It is generally acceptable to assume a density of 1000 kg/m3 for the liquid phase (usually water).

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Description

Explore the economic viability of ore extraction and the influence of microscopic properties on mineral liberation and processing methods. This quiz covers critical concepts such as hydrometallurgy, pyrometallurgy, and the impact of microstructure on separation techniques.