Size separation techniques are methods used to separate a mixture of particles into different groups based on their size. These techniques are widely used in various industries, including food, pharmaceuticals, chemicals, and mining. Here are some of the most common size separation techniques: Sieving: This is a simple and mechanical method that involves passing a mixture of particles through a series of sieves with different mesh sizes. Larger particles are retained on the sieve with the larger mesh size, while smaller particles pass through and are collected. Filtration: This method uses a filter medium to separate particles from a liquid or gas. The size of the pores in the filter determines which particles can pass through. Sedimentation: This method is based on the principle that larger particles settle faster than smaller particles in a fluid. The mixture is allowed to stand, and the larger particles settle to the bottom, while the smaller particles remain suspended. Elutriation: This method uses a stream of air or gas to separate particles. The air velocity is adjusted so that only particles of a certain size range are carried away. Centrifugation: This method uses a centrifuge to create a centrifugal force that separates particles based on their size and density. The heavier and larger particles are forced to the outside of the centrifuge tube, while the lighter and smaller particles remain in the center. Additional techniques: Flotation: Utilizes air bubbles to separate hydrophobic particles from water. Magnetic separation: Applicable for magnetic particles or those tagged with magnetic beads. Laser diffraction: Measures particle size distribution non-destructively. Factors affecting size separation: Particle size: The size range and distribution of particles in the mixture significantly impact the chosen technique's efficiency. Particle shape: Spherical particles are easier to separate than irregular shapes, which can affect how they interact with the separation mechanism. Particle density: The difference in density between particles plays a crucial role in techniques like sedimentation and centrifugation. Fluid properties: In techniques like elutriation and filtration, the viscosity and density of the fluid influence particle movement and separation. Desired separation: Specifying the required size fractions and size distribution is crucial for selecting the appropriate technique.

1. SIZE SEPARATION
AKANKSHA PATEL
ASSISTANT PROFESSOR
AT TAGORE INSTITUTE OF PHARMACY AND RESEARCH,
SAKRI, BILASPUR, CG

2. Contents-
 Objectives,
 applications & mechanism of size separation,
 official standards of powders,
 sieves,
 size separation Principles, construction, working, uses, merits and demerits
of-
 Sieve shaker,
 cyclone separator,
 Air separator,
 Bag filter,
 elutriation tank.

3. SIZE SEPARATION
DEFINITION- SIZE SEPARATION IS A UNIT OPERATION THAT INVOLVE THE SEPARATION OF
MIXTURE OF VARIOUS SIZE OF PARTICLE INTO TWO OR MORE PORTION BY MEANS OF
SCREENING SURFACE.
• IT'S A PROCESS OF SEPARATING PARTICLES OF DIFFERENT SIZE.
• AS SIZE REDUCTION PROCESS DO NOT GIVE PARTICLES OF SAME SIZE.
• SIZE SEPARATION ALSO KNOWN AS SIEVING , SIFTING , SCREENING.
• SCREENING IS A METHOD TO SEPARATING PARTICLE SIZE ACCORDING TO SIZE.

4. OBJECTIVE & APPLICATION OF SIZE SERATION
• TO IMPROVE MIXING
• TO AVOID VARIATION IN PHYSICOCHEMICAL PROPERTY
• TO OBTAIN STABLE SUSPENSION
• USEFUL IN MANUFACTURING OF TABLET AND CAPSULE TO AVOID WEIGHT VARIATION
DURING GRANULATION PREPARATION.
• TO OBTAIN POWDER OF DESIRED SIZE, SIZE SEPARATION NEED TO BE DONE

5. APPLICATION
• UNIFORM SIZE PARTICLES ARE EASY TO FILL IN CAPSULE WHICH GIVE GOOD FLOW
PROPERTY.
• UNIFORM SIZE PARTICLES GIVE PROPER FLOW OF FORM HOPPER WHICH AVOID
WEIGHT VARIATION.
• USEFUL TOOL IN QC. TESTING PARAMETER OF RAW MATERIAL.
• REMOVAL OF IMPURITY ON THE BASIS OF SIZE.
• FOR ORAL USE OF DRUG NEED VERY SMALL SIZE I.E. 10 MICRO METER WHICH CAN BE
DONE BY SIZE SEPARATION TECHNIQUE.

6. MECHANISM
3 TYPES OF MECHANISMS-
1. AGITATION
A. OSCILLATION
B. VIBRATION
C. GYRATION
2. BRUSHING
3. CENTRIFUGAL

7. AGITATION
1. OSCILLATION (SWINGING MOVEMENT) — SIEVE MOUNTED IN FRAME THAT IT CAN BE
SWING. SIMPLE METHOD. MATERIAL ROLL OVER THE SURFACE OF SIEVE.
FIBROUS MATERIAL FORM A BALL ON SIEVE.
2. VIBRATION - SIEVE VIBRATE AT DIFFERENT SPEED ELECTRICALLY. HIGH SPEED APPLY ON
SIEVE TO AVOID BLOCKAGE ON MESH.
3. GYRATION - SYSTEM IS MADE SO THAT SIEVE IS ON RUBBER MOUNTING AND
CONNECTED TO AN ECCENTRIC FLY WHEEL. IT GIVES A ROTARY MOVEMENT OF SMALL
AMPLITUDE TO SIEVE WHICH GIVES SPINNING MOTION TO THE PARTICLES THAT HELPS TO
PASS THEM THROUGH A SIEVE.

8. BRUSHING
IN THIS CASE, A BRUSH IS USED TO MOVE THE PARTICLES ON THE SURFACE OF THE SIEVE
AND TO KEEP THE MESHES CLEAR. THE BRUSH IS ROTATED IN THE MIDDLE IN THE CASE OF
A CIRCULAR SIEVE BUT SPIRAL BRUSH IS ROTATED ON THE LONGITUDINAL AXIS IN CASE
OF A HORIZONTAL CYLINDRICAL SIEVE.
CENTRIFUGAL
IN THIS METHOD, A HIGH SPEED ROTOR IS FIXED INSIDE THE VERTICAL CYLINDRICAL
SIEVE, SO THAT ON ROTATION OF ROTOR THE PARTICLES ARE THROWN OUTWARDS BY
CENTRIFUGAL FORCE. THE CURRENT OF AIR WHICH IS PRODUCED DUE TO HIGH SPEED OF
ROTOR HELPS IN SIEVING THE POWDER

9. OFFICIAL STANDARD FOR POWDER SIZE
AS PER L.P, SIZE OF POWDER EXPRESSED BY MESH SIZE OF SIEVE THROUGH WHICH IT PASS.
CLASSIFICATION OF POWDERS ARE AS FOLLOWS :
1. COARSE POWDER- ALL PARTICLES OF POWDER PASS THROUGH A SIEVE HAVING MESH
SIZE 1.70MM (10 NO. SIEVE) AND NOT MORE THAN 40% THROUGH SIEVE HAVING MESH
SIZE 355 ΜM (44 SIEVE) IS KNOWN AS COARSE POWDER.
2. MODERATELY COARSE POWDER- ALL PARTICLES OF POWDER PASS THROUGH A SIEVE
HAVING MESH SIZE 710 NM (22 NO. SIEVE) AND NOT MORE THAN 40% THROUGH SIEVE
HAVING MESH SIZE 250 NM (60 SIEVE) IS KNOWN AS MODERATELY COARSE POWDER.
3. MODERATELY FINE POWDER- ALL PARTICLES OF POWDER PASS THROUGH A SIEVE
MESH SIZE 355 ΜM (85 SIEVE) IS KNOWN AS MODERATELY FINE POWDER.
4. FINE POWDER- ALL PARTICLES OF POWDER PASS THROUGH A SIEVE HAVING MESH SIZE
180 ΜM (85 SIEVE) IS KNOWN AS FINE POWDER.
5. VERY FINE POWDER- ALL PARTICLES OF POWDER PASS THROUGH A SIEVE HAVING MESH
SIZE 125 ΜM (120 SIEVE) IS KNOWN AS FINE POWDER.

10. INSTRUMENT USED FOR SIZE SEPARATION
1. SIEVE SHAKER
2. CYCLONE SEPARATOR
3. AIR SEPARATOR
4. FILTER BAG
5. ELUTRIATION TANK

11. SIEVE
SIEVE IS A DEVICE HAVING NUMBERS OF HOLE (MESH) OF DIFFERENT DIMENSION.
MATERIAL NEED TO PLACED ON SURFACE OF SIEVE FOR SIEVING (SIZE SEPARATION).
PARTICLES HAVE SIZE LESS THEN MESH SIZE , IT CAN PASS THROUGH THAT SIEVE BUT IF
PARTICLES ARE LARGER THAN MESH SIZE, IT RETAINED ON SURFACE OF SIEVE.
WE CAN SAY, PARTICLES ARE SEPARATED ON THE BASIS OF THEIR SIZE AFTER SIEVING.
ACCORDINGLY WE CAN CATEGORIZED THE POWDER AS COARSE, FINE
SIEVES MADE UP OF WIRE CLOTH WITH SQUARE MESH , WOVEN FROM WIRE OF BRASH,
BRONZE , STAINLESS STEEL.

12. Sieve-
PRINCIPLE:
MECHANICAL SIEVES USE A MECHANICAL SHAKING MOTION TO AGITATE THE
PARTICLES AND CAUSE THEM TO FALL THROUGH THE MESH OPENINGS. THE
PARTICLES THAT ARE LARGER THAN THE MESH OPENINGS WILL BE RETAINED ON THE
SIEVE, WHILE THE PARTICLES THAT ARE SMALLER THAN THE MESH OPENINGS WILL
PASS THROUGH.
ADVANTAGES:
•MECHANICAL SIEVES ARE SIMPLE AND EASY TO USE.
•MECHANICAL SIEVES ARE RELATIVELY INEXPENSIVE.
•MECHANICAL SIEVES CAN BE USED TO SEPARATE A WIDE RANGE OF PARTICLE SIZES.
DISADVANTAGES:
•MECHANICAL SIEVES CAN BE NOISY.
•MECHANICAL SIEVES CAN BE TIME-CONSUMING TO USE.
•MECHANICAL SIEVES CAN BE DAMAGED BY WET OR STICKY MATERIALS.

13. CONSTRUCTION:
MECHANICAL SIEVES TYPICALLY CONSIST OF A
METAL FRAME WITH A MESH SCREEN ATTACHED. THE
MESH SCREEN IS MADE OF A VARIETY OF MATERIALS,
SUCH AS STAINLESS STEEL, NYLON, OR POLYESTER.
THE MESH SCREEN IS PERFORATED WITH A SERIES OF
HOLES OF DIFFERENT SIZES. THE SIZE OF THE HOLES
DETERMINES THE SIZE OF THE PARTICLES THAT CAN
PASS THROUGH THE SIEVE.
WORKING:
THE MATERIAL TO BE SIEVED IS PLACED ON THE
MESH SCREEN AND THE SIEVE IS SHAKEN BACK AND
FORTH. THE SHAKING MOTION CAUSES THE
PARTICLES TO MOVE AROUND AND COME INTO
CONTACT WITH THE MESH OPENINGS. THE PARTICLES
THAT ARE LARGER THAN THE MESH OPENINGS WILL
BE RETAINED ON THE SIEVE, WHILE THE PARTICLES
THAT ARE SMALLER THAN THE MESH OPENINGS WILL
PASS THROUGH.

14. Sieve shaker machine

15. AIR SEPARATOR
PRINCIPLE -
CENTRIFUGAL FORCE APPLY TO SEPARATE SOLID. AIR ENVIRONMENT OBTAIN BY USING
ROTATING DISC AND BLADE. TO IMPROVE SEPARATION , STATIONARY BLADES ARE USED.
FINE PARTICLES ARE CARRY AWAY BY AIR AND COARSE PARTICLES THROWN BY
CENTRIFUGAL FORCE WHICH FALL AT BOTTOM.
USES- USED IN HAMMER MILL, BALL MILL TO SEPARATE PARTICLE. AND RETURN
OVERSIZED PARTICLE FOR FURTHER SIZE REDUCTION.
ADVANTAGES- LOW PRESSURE DROP, LOW MAINTENANCE, HIGH QUALITY PRODUCT, GIVE
EFFICIENT SEPARATION IN SMALLER APPARATUS.
DISADVANTAGES - LOW SEPARATION YIELD, UNSUITABLE FOR SEPARATING SMALLER
PARTICLE

16. CONSTRUCTION-
IT CONSIST CYLINDRICAL VESSEL WITH CONICAL BASE.
ROTATING PLATE IS FITTED ON A SHAFT PLACED AT CENTRE OF
VESSEL.
FEEDER PLACED AT THE UPPER PART OF VESSEL.
SET OF FAN BLADE ALSO FITTED WITH SAME SHAFT.
AT BASE OF VESSEL, TWO OUTLETS PROVIDED.
WORKING-
FAN AND DISC ROTATE BY MOTOR. POWDER FROM FEEDER ENTER
AT CENTRE OF VESSEL AND FALL ON ROTATING DISC. ROTATING FAN
BLADE PRODUCE FLOW OF AIR IN DIRECTION. FINE PARTICLE CARRY
BY FLOW OF AIR INTO SPACE OF SETTLING CHAMBER AND
REMOVED FROM FINE PARTICLE OUTLET. AND HEAVY PARTICLE PICK
BY AIR STREAM AND REMOVE AT COARSE.

17. Air separator-

18. Cyclone separator
CYCLONE SEPARATOR PRINCIPLE
CYCLONE SEPARATORS WORK ON THE PRINCIPLE OF CENTRIFUGAL FORCE. THE MATERIAL TO BE SEPARATED IS
FED INTO THE CYCLONE SEPARATOR TANGENTIALLY. THIS CREATES A SWIRLING MOTION IN THE CYCLONE
SEPARATOR. THE CENTRIFUGAL FORCE CAUSES THE LARGER PARTICLES TO MOVE TO THE OUTSIDE OF THE
CYCLONE SEPARATOR, WHILE THE SMALLER PARTICLES REMAIN SUSPENDED IN THE CENTER. THE LARGER
PARTICLES THEN FALL TO THE BOTTOM OF THE CYCLONE SEPARATOR, WHILE THE SMALLER PARTICLES ARE
CARRIED OUT OF THE CYCLONE SEPARATOR IN THE GAS STREAM.
ADVANTAGES
•CYCLONE SEPARATORS ARE VERY EFFICIENT AT SEPARATING PARTICLES OF DIFFERENT SIZES.
•CYCLONE SEPARATORS CAN HANDLE A WIDE RANGE OF FLOW RATES AND PARTICLE SIZES.
•CYCLONE SEPARATORS ARE RELATIVELY INEXPENSIVE TO OPERATE AND MAINTAIN.
•CYCLONE SEPARATORS HAVE NO MOVING PARTS, WHICH MAKES THEM RELIABLE AND LOW-MAINTENANCE.
DISADVANTAGES
•CYCLONE SEPARATORS CAN BE NOISY.
•CYCLONE SEPARATORS CAN BE DIFFICULT TO CLEAN, ESPECIALLY IF THEY ARE USED TO SEPARATE STICKY
MATERIALS.
•CYCLONE SEPARATORS CAN BE LESS EFFICIENT THAN OTHER TYPES OF SEPARATORS, SUCH AS BAG FILTERS, FOR
SEPARATING VERY SMALL PARTICLES.

19. CONSTRUCTION
CYCLONE SEPARATORS ARE TYPICALLY MADE OF METAL
OR PLASTIC. THEY CONSIST OF A CYLINDRICAL
CHAMBER WITH A CONICAL BOTTOM. THE MATERIAL TO
BE SEPARATED IS FED INTO THE CYCLONE SEPARATOR
TANGENTIALLY THROUGH AN INLET AT THE TOP OF THE
CHAMBER. THE GAS STREAM EXITS THE CYCLONE
SEPARATOR THROUGH AN OUTLET AT THE TOP OF THE
CHAMBER.
WORKING
WHEN THE MATERIAL TO BE SEPARATED IS FED INTO THE
CYCLONE SEPARATOR TANGENTIALLY, IT CREATES A
SWIRLING MOTION IN THE CYCLONE SEPARATOR. THE
CENTRIFUGAL FORCE CAUSES THE LARGER PARTICLES
TO MOVE TO THE OUTSIDE OF THE CYCLONE
SEPARATOR, WHILE THE SMALLER PARTICLES REMAIN
SUSPENDED IN THE CENTER. THE LARGER PARTICLES
THEN FALL TO THE BOTTOM OF THE CYCLONE
SEPARATOR, WHILE THE SMALLER PARTICLES ARE
CARRIED OUT OF THE CYCLONE SEPARATOR IN THE GAS
STREAM.

20. Cyclone separator

21. BAG FILTER
PRINCIPLE- THE SEPARATION OF FINE POWDER FROM COARSE POWDER IS OUT BY
APPLYING SUCTION. FIRSTLY, THE MIXTURE OF POWDER WHICH IS TO BE SEPARATED IS
PASSED THROUGH A BAG WHICH IS MADE UP OF CLOTH BY APPLYING SUCTION AT
OPPOSITE SIDE OF THE FEEDING. THIS CAUSES THE SEPARATION OF FINE & COARSE
POWDER.
USES- USED ON TOP OF FLUIDIZED BRAVER FOR DRYING TO SEPARATE THE DUST, TO
CLEAN THE ROOM AIR, HOUSEHOLD VACUUMED CLEANER IS SIMPLE VERSION OF BAG
FILTER.
ADVANTAGES- USES TO REMOVE DUST, REDUCE SENSITIVITY TO PARTICLE SIZE
DISTRIBUTION, NO HIGH VOLTAGE REQUIRE.
DISADVANTAGES- LOSS OF CLEANING EFFICIENCY, LARGE PRESSURE LOSSES, IT HAS A
HIGH RESISTANCE WITH ABOUT 600-1200.

22. CONSTRUCTION- IT CONSISTS OF NUMBER OF BAGS MADE OF
COTTON OR WOOL FABRICS. THESE ARE SUSPENDED IN A METAL
CONTAINER. A HOPPER IS ARRANGED AT THE BOTTOM OF THE
FILTER TO RECEIVE THE FEED. AT THE TOP OF THE METAL
CONTAINER, A PROVISION IS MADE FOR VACUUM FAN. AT THE TOP
OF THE VESSEL A BELL-CRANK LIVER ARRANGEMENT IS MADE TO
CHANGE THE ACTION FORM FILTERING TO SHAKING.
WORKING- 01). FILTERING PERIOD: DURING THIS PERIOD THE
VACUUM FAN PRODUCES A PRESSURE LOWER THAN THE
ATMOSPHERIC PRESSURE WITH IN THE VESSEL. GAS TO BE
FILTERED ENTERS THE HOPPER, PASSES THROUGH THE BAGS, &
OUT OF THE TOP OF THE APPARATUS. THE PARTICLES ARE
RETAINED WITH IN THE BAGS.
02). SHAKING PERIOD- DURING THIS PERIOD THE BELL-CRANK
LIVER FIRST CLOSE THE DISCHARGE MANY FOLD & AIRS ENTERS
THROUGH: THE TOP SO THE VACUUM IS BROKEN. AT THE SAME
TIME, IT GIVES A VIOLENT JERKING ACTION TO THE BAGS SO THAT
THEY ARE FREED FOR THE DUST. THE FINE PARTICLES ARE
COLLECTED AT THE CONICAL BASE.

23. Bag filter

24. Elutriation tank
ELUTRIATOR PRINCIPLE- ELUTRIATORS WORK ON THE PRINCIPLE OF FLUIDIZATION.
FLUIDIZATION IS THE PROCESS BY WHICH PARTICLES ARE SUSPENDED IN A FLUID BY
FLOWING THE FLUID UPWARDS THROUGH THE PARTICLES. THE FLUID VELOCITY DETERMINES
THE SIZE OF THE PARTICLES THAT ARE FLUIDIZED. SMALLER PARTICLES ARE FLUIDIZED AT
LOWER VELOCITIES, WHILE LARGER PARTICLES ARE FLUIDIZED AT HIGHER VELOCITIES.
ELUTRIATOR ADVANTAGES
•ELUTRIATORS ARE VERY EFFICIENT AT SEPARATING PARTICLES OF DIFFERENT SIZES.
•ELUTRIATORS CAN HANDLE A WIDE RANGE OF FLOW RATES AND PARTICLE SIZES.
•ELUTRIATORS CAN BE USED TO SEPARATE PARTICLES IN A CONTINUOUS OR BATCH MODE.
•ELUTRIATORS ARE RELATIVELY INEXPENSIVE TO OPERATE AND MAINTAIN.
ELUTRIATOR DISADVANTAGES
•ELUTRIATORS CAN BE NOISY.
•ELUTRIATORS CAN BE DIFFICULT TO CLEAN, ESPECIALLY IF THEY ARE USED TO SEPARATE
STICKY MATERIALS.
•ELUTRIATORS CAN BE LESS EFFICIENT THAN OTHER TYPES OF SEPARATORS, SUCH AS BAG
FILTERS, FOR SEPARATING VERY SMALL PARTICLES.

25. CONSTRUCTION
ELUTRIATORS TYPICALLY CONSIST OF A VERTICAL COLUMN
WITH A TAPERED BOTTOM. THE MATERIAL TO BE SEPARATED IS
FED INTO THE ELUTRIATOR AT THE TOP OF THE COLUMN. THE
FLUID ENTERS THE ELUTRIATOR AT THE BOTTOM OF THE
COLUMN AND FLOWS UPWARDS THROUGH THE MATERIAL. THE
FLUID VELOCITY IS CONTROLLED TO FLUIDIZE THE DESIRED
SIZE PARTICLES. THE FLUIDIZED PARTICLES ARE THEN
CARRIED OUT OF THE ELUTRIATOR AT THE TOP OF THE
COLUMN. THE LARGER PARTICLES THAT ARE NOT FLUIDIZED
REMAIN IN THE ELUTRIATOR AND ARE REMOVED FROM THE
BOTTOM OF THE COLUMN.
WORKING
WHEN THE MATERIAL TO BE SEPARATED IS FED INTO THE
ELUTRIATOR AT THE TOP OF THE COLUMN, THE FLUID ENTERS
THE ELUTRIATOR AT THE BOTTOM OF THE COLUMN AND
FLOWS UPWARDS THROUGH THE MATERIAL. THE FLUID
VELOCITY IS CONTROLLED TO FLUIDIZE THE DESIRED SIZE
PARTICLES. THE FLUIDIZED PARTICLES ARE THEN CARRIED
OUT OF THE ELUTRIATOR AT THE TOP OF THE COLUMN. THE
LARGER PARTICLES THAT ARE NOT FLUIDIZED REMAIN IN THE
ELUTRIATOR AND ARE REMOVED FROM THE BOTTOM OF THE
COLUMN.

26. Elutriation tank

27. Thank you!!!