Particle Technology Flashcards by Alexander Busto

Equivalent Diameter is the diameter of the sphere having the same

ratio of surface to volume as the actual volume

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Sphericity of Cylinder having equal L and D

0.87

S = π⅓ (6V)⅔ ÷ SA
S = 6V ÷ (SA*D)

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Sphericity of hedrons

Tetra - 0.67
Hexa - 0.81
Octa - 0.84
Dodeca - 0.91
Icosa - 0.94

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Units of measurements used for different sizes of particles

Coarse - mm, in, cm
Fine - mesh or screen size
Very fine - microns, nano
Ultrafine - SA/mass (e.g., m²/g)

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Short distance transportation of grain gravel, sand is done using

screw conveyor

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Power requirement of ball mill is proportional to

D^2.5

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Screen for sizing very fine materials

Vibrating Screen

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Plate and frame filter operates by

pressure

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Tabular bowl centrifuges operate at ____ as/than disk bowl centrifuge

a. lower speed
b. higher speed
c. same speed

higher speed

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Pebbles used in pebble mills are made of

flint or porcelain

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Agitator for fibrous and dense slurries

Cone type

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Centrifuge used in sugar mills

Suspended batch basket

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Mesh sizes of this screen is arranged from smallest to largest. Used for powdered and granular feeds

Reciprocating screens

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Mesh number is defined as

Number of apertures per linear inch

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How to relate mesh number to screen opening/aperture?

Mesh Number (Aperture + Wire Diameter) = 1

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Screen interval of Tyler Standard Sieve Series

√2

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United States Sieve Series screen interval is

⁴√2

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Cumulative Analysis or Plot in screening

Larger than Dp - mass fraction is the overflow of the mesh

Smaller than Dp - mass fraction is the underflow of the mesh

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Relationship of screen effectiveness and screen capacity

Inverse

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Ball mills and tube mills with flint or porcelain balls are used for size reduction of

non-metallic ores

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Size reduction of ____ is accomplished in steam heated rollers and roll crushes

a. waxes
b. resins
c. gums
d. rubber

Rubber

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Filter media is used to

increase the porosity if cake

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Froth floatation is mist suitable for

a. iron ores
b. quartzite
c. sulfide ores
d. none

sulfide ores

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Taggart’s formula

T=0.6LS

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Equipment for Coarse, Hard Materials

Jaw crusher and Gyratory crusher T/S² < 0.115 Jaw T/S² > 0.115 Gyratory

Equipment for Coarse, Soft Materials ,e.g., gypsum, coal, ice, fire, shales, clay

Brandford breaker for coal Tooth roll crusher (by pressure) Hammer Mill Squirrel Cage Disintegrator

Equipment for Intermediate size reduction

Crushing rolls (2 rolls rotating in opposite direction) Cone crushers Edge runner (clay industry)

Crushing roll, angle of nip formula

angle = 2@ cos @ = (r1 + b) ÷ (r1+r2)

Mill used in paint, pigment, cosmetics manufacturing a. Ball mill b. Pebble mill c. Rod mill d. Hammer mill

Pebble mill

Speed when centrifuging (balls are carried iver due to very high speed) occurs in the mill

Critical speed

Equipment for Ultrafine size reduction

Classifying Hammer Mill Fluid Energy Mill Agitated Mill Colloid Mill

Energy required for size reduction is proportional to the length of the initial and final diameters

Kick's Law (n=1) P/T = k ln (x1/x2)

Energy requirement is proportional to the new surface created

Rittinger's Law (n=2) P/T = k (1/x2 - 1/x1)

Rittinger's formula given specific surface area and rittinger's number

P/T = (Sp-Sf) / Rittinger's No. Rittinger's Number = 1/Kr

Energy requirement is proportional yo the square root of the surface to volume ratio of the product

Bond's Law (n=1.5) P/T = K (x2 -½ --- x1 -½)

Cleaning of fine coal dust (<0.5 mm)

Froth floatation

Range of compressibility coefficient of commercial compressible cake obtained in filtration is a. 0.01 to 0.1 b. 0.1 to 0.5 c. 0.2 to 0.8 d. 0.8 to 1.2

0.2 to 0.8

The value of angle of nip is generally about

32°

Sulfuric acid mist is arrested by using ____ scrubber

venturi

Main size reduction in ultra-fine grinders a. compression b. attrition c. impact d. cutting

Attrition coarse - compression fine - impact very fine - attrition

Jigging is a technique by which particles can be separated by a. particle density b. particle shape c. particle size d. all

particle size

A cage mill is a ____ mill a. roll b. vibratory c. impact

impact mill

Diatomaceous Earth is an example of

filter aid

Separator for milk cream a. disc bowl centrifuge b. sharpies supercentrifuge c. batch basket centrifuge

disc bowl

Grindability is independent of a. size b. elasticity c. hardness d. tougness

size

Shape factor for a cylinder whose L=D

1.5

Dust laden air is purified using a. cyclone separator b. bag filter c. tubular centrifuge

cyclone separator

Higher rittinger's number of material indicates _____ grindability a. poorer b. better

better

Mixer used for devulcanization of rubber scarp and making water dispersion and rubber solution a. Banbery b. Tumbler c. Muller

Banbery

Conveyors under "scrapers"

Ribbon Flight Drag

L/D of ball mill us a. 1 b. greater than 1 c. less than 1

less than 1

Conveyor for sticky material

Screw conveyor, which is not part of "carrier" division

Filtration of water in a paper mill is done by using what filter a. open sand b. leaf c. plate and frame d. sparkler

open sand

Also called as Moore filter

Leaf filter

For ball mill, coarse particles will require _____ balls a. large b. small

large

Flow if filtrate through a cake in a PFF is best described by what equation

Kozney-Karman

Resistance offered by the bag filter is proportional to

concentration of dust/particle size

Mill for cement clinker a. ball b. rod c. tube d. hammer e. pebble

tube

Geometric mean of the relative rejections and the relative recoveries of 2 minerals

Selectivity index

Mixer for rubber and plastic solids

Banbery

Maximum attainable velocity

Free settling or terminal velocity

b and n for the three ranges of particle motion

Stokes 24,1 Re <2 Intermediate 18.5,0.6 Re 2-500 Newton 0.44,0 Re >500 K = Ar⅓ >3.3 - 44<

Rate of settling is not constant as the movement of particle is impeded by nearby particles

Hindered Settling

Separation of sugar solution from settled out mud, we use ____ filter

centrifugal

Mixing light fine powder of insecticide is done by

Impact wheel

Size reduction of mica and asbestos is done in a. gyratory crusher b. crushing rolls c. hammer mill

hammer mill

Moisture can be removed from lubricating oil using

tubular centrifuge

In tabling, table/deck is inclined from horizontal at an angle of

2-5°

Gizzlies are used to separate __ solids a. coarse b. fine c. very fine

fine

Reduction ratio of fine grinders

up to 100

Reduction ratio

Ratio of feed opening to discharge opening

Separation of isotopes is done using

ultra-centrifuge

Particle Technology Flashcards

(72 cards)