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What percentage of the total sample is less than 1.0 μ?
What is the total percentage of weight in the given data?
What is the cumulative weight percentage of particles with size class 0.1 μ?
What is the total weight of the sample?
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What is the particle size class with the highest cumulative weight?
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What percentage of the total sample is more than 1 μ?
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What does the x-axis represent in the histogram?
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What is the cumulative weight percentage of particles with size class 1.5 μ?
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What is the purpose of a cumulative frequency curve?
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What is the weight percentage of particles with a size class of 1.5 μ?
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How many particles have a size class less than or equal to 0.5 μ?
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What is the cumulative weight of particles with size class 2.0 μ?
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What is the term for a graph that shows the relative amount of particles in each size class?
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What does the y-axis represent in the histogram?
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What is the weight percentage of particles with size class 3.0 μ?
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What is the term for a smooth curve that represents the size distribution of the sample?
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What is the primary objective of size separation?
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What factors affect the efficiency of size separation?
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What is the range of particle size that can be separated using sieving?
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What is the importance of the uniform circular cross-section of the wire mesh in sieves?
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How can data on particle size distributions be normally collected?
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What is the primary consideration when choosing a method for particle sizing?
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What is the purpose of sieving in particle size separation?
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How can the data on particle size distributions be presented?
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What is the principle behind sedimentation methods?
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What is the range of particle sizes that can be separated using centrifugal sedimentation?
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What equation predicts the settling velocity of small spheres in a fluid?
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What is the process by which particulates settle to the bottom of a liquid and form sediment?
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What is the purpose of pipette in sedimentation methods?
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What is the unit of measurement for particle size in the graph shown?
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Which of the following is NOT a method to determine particle size distribution?
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What is the term for the settling velocity of small spheres in a fluid?
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What is the direction of fluid flow in an elutriation method?
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What happens to dense particles in an elutriation method?
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What determines the size of particles that will be separated in an elutriation method?
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What is the movement of the suspension in a cyclone method?
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What happens to the largest particles in an elutriation method?
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What is the direction of sedimentation movement in an alternative sedimentation method?
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What happens to the clarified liquid in an alternative sedimentation method?
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What determines the separation of particles in an alternative sedimentation method?
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Study Notes
Particle Size Separation
- Definition: Solid separation is a process by which powder particles are removed from gases or liquids.
- Objectives:
- To recover valuable products or byproducts
- To prevent environmental pollution
Size-Separation Efficiency
- Efficiency depends on:
- Particle and fluid properties
- Separation method used
- Separation efficiency is determined by the effectiveness of a process in separating particles into oversize and undersize fractions
Methods for Particle Size Measurement
- Choosing a method for particle sizing depends on:
- Nature of the material to be sized
- Estimated particle size and particle size range
- Solubility
- Ease of handling
- Toxicity
- Flowability
- Intended use
- Cost (capital and running)
- Specification requirements
- Time restrictions
Size Separation Methods
-
- Sieving:
- Size separation ranges: 5-10000μm
- Most widely used method of analysis
- Different grades of sieves are used for sifting the powders
- Wire mesh of the sieves should be of uniform circular cross-section, and should possess adequate strength to avoid distortion and be resistant to chemical action with the material to be sifted
Statistical Summarization of Particle Size Distribution
- Data on particle size distributions are normally collected by sieving
- Presentation of data:
- Table form
- Graph form
Cumulative Frequency Curves
- A smooth curve that represents the size distribution of the sample
- Readily shows the relative amount of particles in each size class
- Readily shows the % of particles in each size class
Methods to Determine Particle Size Distribution
- Microscopy
- Sieving methods
- Sedimentation methods
- Particle counting methods
- Laser/Light diffraction methods
Sedimentation Methods
- Separation ranges:
- Centrifugal sedimentation up to 4μm
- Gravitational sedimentation, 4-1000μm
- Principle: Size separation by sedimentation utilizes the differences in settling velocities of particles with different diameters
- Stokes' Law predicts the settling velocity of small spheres in fluid
Alternative Sedimentation Methods
- A. Simple Technique:
- Suspension of solid particles in a liquid
- After predetermined times, particles less than a given diameter can be recovered using pipette
- B. Alternative:
- Feed enters the center of the bowl and the suspension passes through each chamber in turn, at increasing distances from the axis
- The solids settle onto the outer wall of each chamber and the clarified liquid emerges as an overflow from the largest diameter chamber
Elutriation Methods
- Elutriation is a technique in which the fluid flows in an opposite direction to the sedimentation movement
- The particles move vertically downwards while the fluid travels vertically upwards
- In the case of elutriation, particles are divided into different size fractions depending on the velocity of the fluid
- Based upon counter flow of fluid (air/water) and settling particles through vertical columns
Cyclone Methods
- The suspension is introduced tangentially at fairly high velocity, so that a rotary movement takes place within the vessel
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Description
This quiz covers the process of solid separation, its objectives, and factors affecting size-separation efficiency. It also explores various methods used in particle size separation.
