Mineral Processing Flashcards
The science and art of separating valuable metallic and non-metallic minerals from unusable gangues
Mineral Processing/ Mineral Beneficiation/ Mineral Engineering/ Ore Dressing
High recovery without the acceptable grade will lead to an _________ product and thus it is often unsatisfactory
Unsalable
Even if the state-of-the-art procedure can recover tons of valuable materials, as long as the process is costly, the process is deemed ______.
Inefficient
The percentage of the valuable material reporting to the concentrate with reference to the amount of material in feed.
____ = (amount of concentrate/ amount of feed)x 100%
Percent Recovery
It refers to the release of valuable minerals between themselves and from the associated gangue at the coarsest possible particle size.
Comminution/ Liberation/ Particle-Size Liberation
These particles are when valuable minerals and gangues and interlocked in a particle.
Middling Particles
This refers to the separation of particles according to their size using nets or screens of desired industry standard perforations.
Sizing/ Screening and Classfication
The separation of minerals into two or more products (the valuable minerals in concentrates, gangues in tailings, and locked particles in middlings).
Concentration
The final process of removing the water content of the mineral in order to dispose of the gangue and reach the desired concentrate levels for marketability
Dewatering/ Solid-liquid Separation
The process prior to the ore being processed.
Ore Handling
Unit Operations of Ore Handling
Cleaning, Transporting, Stockpiling, Mill Feed Analysis
Intermixing by blending of the run-of-mine ore _______ homogeneity and consistency before feeding
maximizes
This process is the removal of unwanted substances present in the run-of-mine ore.
Cleaning
This process is the removal of unwanted substances present in the run-of-mine ore.
Cleaning
Methods of Cleaning
Hand Sorting, Electromagnetic Separation over a conveyor belt, and Washing of clays and slimes
The process of transporting the run-of-mine ore by various means depending on its characteristics
Transporting
It is a form of transport in which cars of special type are suspended from overhead ropes employed for conveying material
Aerial Ropeway
Aerial Ropeways based on its conveying properties are either:
Single Cable or Bia-Cable
1) Can travel in long distances
2) Lower Capital Cost
3) Eco-friendly
4) Good Transportation
Advantages of Aerial Ropeways
1) Limited scope
2) Straight-line device
3) Change in vertical direction needed
4) Slow
Disadvantages
A widely used across the construction and mining industry for the handling of heavy materials.
Dumper Trucks/ Tipper/ Haul Truck
The Biggest Tipper/ Haul Truck
BelAZ 75710 Dump Truck (20.6m and 450t, Belarussian-Russian)
It transports ore and other materials from the mining site to processing facilities or loading areas.
Conveyor Belts
The middle layer of the conveyor belt system that helps support the belt.
Carcass
It consists of various layers of fabric separated by rubber, which helps deaden impact. Tend to be longer-lasting and are used for underground applications.
Multi-ply Conveyor Belt
Ideal for tunneling applications, they’re most often used in rock quarries and rock crushers.
Straight-warp Conveyor Belt
Steel cables running the entire length of the belt anchor this type of conveyor belt, which is used for underground applications.
Steel-cord
In underground mining belts, impregnation paste, and rubber components are added during manufacturing to help _______ the friction factor and _____ fire resistance.
decrease, increase
The accumulation of ore or mineral built up when demand slackens or when the treatment plant or beneficiation equipment is incomplete or temporarily unequal to handling the mine output
Stockpiling
Factors that affect the quantity of storage
1) Size of Operation
2) Frequency of Unexpected Breakdown
3) Shutdown of Individual Units
Factors that affect the quantity of storage
The reference to the amount of moisture present in the material often expressed as a percentage.
_______ = ((Wet Weight- Dry Weight)/ Wet Weight) x 100%
Moisture Content
The best possible grade representation in mineral processing.
75 microns when homogenous
The weight of the concentrate is determined by deducting the ________
Moisture Factor
It is the difference between the weight of the feed and weight of the concentrates.
Tailing Weight
This allow the direction of elements present in the system to measure the sensitivity of base and noble metals and in the production of a clean concentrate
In-stream Analyzers
These are any non-ferrous (they contain no iron) metals that are neither precious metals nor noble metals (Au, Ag, Pt, Pd).
Noble Metals
These are common and inexpensive metals characterized by oxidizing and corroding relatively easily and reacting variably with HCl to form H (Cu, Pb, Ni, Zn).
Base Metals
It employs sensors acting as a source of radiation absorbed by sample causing a fluorescent response.
In-stream X-ray Analyzer
It is installed in feed, concentrate, and tailings streams where it is analyzed by electrical circuits in a computer.
Analyzer Probes
This shows the elemental dispersion at every minute available. It is done manually or by automation in controlling reagents during froth flotation.
Digital Process Control Module
This is used to determine the quality of grind and establish degree of liberation of valuable minerals.
Particle Size Analysis
The general expression for separation of particles
Sizing
The diameter of a spherical particle which behaves similar to an irregular particle under specified conditions.
Equivalent Size/ Diameter
A diameter having the same surface area as the irregular particle
Surface Diameter
A diameter having the same volume as the irregular particle
Volume Diameter
A circular shell of brass having an 8in diameter and 2in height used in testing materials.
Test Sieve
This is made of thin wires woven to produce a uniform cloth apertures. It is placed at the bottom of the shell so that material can be held on the sieve.
Sieve Cloth
The distance between 2 parallel wires
Apertures/ Opening
The number of apertures per linear inch which designates sieves.
Mesh Number
The size of the aperture
Mesh Size
As mesh number increases, the mesh size __________
Decreases
This refers to the list of successive sieve sizes used in any lab from coarsest to finest
Sieve Scale
It is adopted for size analyses and general testing work to facilitate the interchangeability of results and data.
Standard Sieve Scale
Standard Sieve Scales follows the:
American Standard for Testing and Materials 11 (ASTM 11)
A method of size analysis performed to determine the percent weight of closely sized fraction by allowing the sample to pass through a series of test sieves
Sieve Analysis
It refers to a material in which the difference between the maximum and minimum sizes is small.
Closely-sized Material
High fluctuation of feed at flotation cells yields a __________ to tailings
A loss to tailings
Comminution starts during
Blasting
The quantity or amount of draw within a given time. It is the rate of production for a process over a specific amount of time.
Throughput
These refer to particles that consist a single material
Free Particles
These consist of 2 or more minerals which is either associated with a gangue or ore mineral
Locked Particles/ Midllings
The size as it occurs in the ore
Grain Size
The size whether free or locked particle
Particle Size
The size at which the mineral is completely liberated
Liberation Size/ Required Size
The ratio of maximum size in feed to the maximum size in the product.
Reduction Ratio
This happens when the mineral particles have similar properties where bonding is stronger. This size reduction must be done.
Transgranular Liberation
This happens when mineral particles can be separated due to weaker bonds causing fracture
Intergranular Liberation
It states that the energy required to crush is the same regardless of the original size. This is applicable for compression of large particles.
Kick’s Law
The energy required for reduction is directly proportional to the increase in surface area. This is for brittle materials undergoing fine milling.
Rittinger’s Law
The energy required is proportional to the square root of the surface-volume ratio. This is useful in rough mill sizing
Bond’s Law
A reasonable amount of crushing for liberation to be done is used in what deposit?
For Massive Ores
The valuables can be freed only partially by crushing and require certain amount of grinding to complete liberation
For Intergrown Ores
It is accomplished by compression of the ore against a rigid surface or by impact against a surface in a rigidly constrained motion path.
Crushing
These machines liberate the rock of 1m to 100-200mm sizes.
Primary Crushers
It has two plates et at an acute angle to each other forming a crushing chamber. One plate is fixed and kept at a vertical angle while the other is a movable or swing plate. This is suitable for soft to very hard ores.
Jaw Crusher/ Toggle Crusher
Reduction Ratio of Jaw Crushers
4/1 to 7/1
It is pivoted at the top and has a fixed receiving area and a variable discharge area. Reduction Ratio at 8/1
Blake Crusher
It is pivoted at the bottom and has a variable receiving area and a fixed discharged area.
Dodge Crusher
It is pivoted in an intermediate position with both the receiving and discharge area variable.
Universal Crusher
The volume/ cavity between the two jaws.
Crushing Chamber
The jaws in the jaw crusher are typically made up of
Cast Iron/ Cast Steel
The distance between two jaw plates at the feed opening.
Gape
The distance between two jaw plates at the discharge opening.
Set
The maximum distance between two jaw plates at the discharge.
Closed Set
The minimum distance between two jaw plates at the discharge.
Open Set
The maximum amplitude of swing of the jaw
Throw
These consist of 2 vertical truncated shells of which the outer hollow conical shell is stationary and the inner solid conical shell is made to gyrate. It has a reduction ratio of 8/1.
Gyratory Crusher
Which of the following has the large throughput? Jaw Crusher or Gyratory Crusher
Gyratory Crusher
A modified gyratory crusher which has straight or curved heads and concaves typically used in secondary to tertiary crushing.
Reduction Gyratory Crusher
These machines liberate the ore of 600mm to 3-25 mm.
Secondary Crushers
A modified gyratory crusher with both the outer and inner conical shells are pointing up
Cone Crusher
Reduction Ratio of Cone Crushers
3/1 to 10/1
It has stepped liners to allow a coarser feed. It has a reduction ratio of 6/1 to 8/1
Standard Cone Crusher
It has a steeper head angle to prevent choking of finer material. It has a reduction ratio of 4/1 to 6/1
Short-head Cone Crusher
It consists of 2 heavy manganese horizontal cylinders revolving towards each other and feed material is nipped between the rolls and pulled downward through rolls by friction. It has the lowest reduction ratio of 2/1 to 4/1
Roll Crusher
Roll crushers are suitable for:
soft and friable ores such as coal, phosphates, limestone, chalk, and etc.
It reduces particles by impact forces which are applied through sharp blows of fixed or free swinging hammers revolving about a central rotor at high speed to the free-falling particles against stationary surfaces.
Impact Crusher
It strikes the material entering the crushing chamber and throwing it against the impact wall causing the material to fracture into smaller particles.
Blow Backs
These are done in closed circuits where size reduction has not completed. It uses secondary crushers where it is necessary to produce fines.
Tertiary Crusher
It resembles a cylindrical trammel screen in operation. It consists of a slightly inclined cylindrical chamber with perforated wall and rotates about its axis at low rpm used both as a crusher and screener.
Bradford Breaker
It is used in hard-rock mining operations where rolls are subjected to high pressure so that comminution takes place by compressive forces as well as by inter-particle breakage.
High Pressure Grinding Rolls
Bradford Breakers are reliable in the:
Coal Industry at 100t/h to 2,200 t/h
It has a spherical steel head and is used for tertiary crushing
Gyrasphere
The final stage in comminution performed in a rotating cylindrical heavy-duty steel vessels either dry or as a suspension in water.
Grinding
Grinding systems reduce materials of 1 cm from crushers to:
35-200 (500 um - 75um) mesh
In gravel operations, sieve sizes used ranges:
3in to 1/2 in
In soil sampling operations, sieve sizes used ranges:
17 mesh - 18 mesh (2.8mm-1mm)
It consist of a horizontal rotating steel shell supported by end bearing on which hollow trunnions revolve. This is used to reduce the particle size of a solid with grinding medium
Grinding Mill/ Tumbling Mill
These are attached inside the mill to protect it from wear and damage.
Liners
These are attached inside the mill to protect it from wear and damage.
Liners
The feed is in a vibrating feeder with added fluid having the viscosity and density of air. This is used in extremely fine products.
Dry Grinding Mill
This is carried out in 20-35% water by weight. It has low power consumption since water adds the fracturing.
Wet Grinding Mill
A type of feeder that uses a series of overlapping steel plates to convey the load suitable to any size of material. A favorite of the mining industry.
Apron Feeder
The entire mill feed enters the drum and an internal spiral carries it and fed to the mill
Drum Feeder
The material is fed to the drum and the scoop picks it up and fed to the mill.
Scoop Feeder
Factors in selecting whether dry or wet grinding mill to be chosen:
1) Economic gain from reduced power demand
2) Increased throughput against increased cost
These are generally used for fine material applications especially 6in or less. These feature a flat belt that is supported by closely spaced idlers and driven at the head pulley.
Belt Feeders
This uses carbon steel or iron balls of 1-6in diameter as the grinding medium. These usually have a length to diameter ratio of 1.5- 1.0
Ball Mills
Ball mills are suited for finer grinding of ________
Hard and coarse feeds such as base metals and phosphates
The rolling of one ball to the other which leads to fine grinding.
Cascading
The free-fall of balls which leads to coarse grinding.
Cataracting
It is defined as the speed at which centrifuging occurs as balls rotate around the shell.
Critical Speed
These are generally used to feed primary crushers in aggregate, mining and recycling applications, but they can also be used to feed grizzly feeders for removing material ahead of a crusher.
Vibrating Pan Feeders
It refers to the action or process of gradually reducing the strength or effectiveness of someone or something through sustained attack or pressure.
Attrition
It uses rods as grinding medium with length to diameter ratio of 1.5-2.5 and are suitable for preparation of feed to gravity and magnetic separation
Rod Mills
Rod mills run at 50-60% critical speed thus rod mills:
Cascade than cataract
Grinding is done by ______ and _____ and exerted preferentially on coarsest particles.
Friction and Attrition
The material is fed at one end of the mills and the ground product is discharged from the other end by means of several peripheral apertures into a close-fitting circumferential chute.
End Peripheral Discharge Mills
The material is fed at both ends of the mill and ground product is discharged through a circumferential port at the center of the shell.
Center Peripheral Discharge Mills
The discharge grates are fitted through which pulp flows freely and lifted up to the level of the discharge trunnions.
Grate Discharge Mills
A grinding mill where length to diameter ratio is 3-5 where it uses ceramic pebbles made of flint or porcelain as grinding media.
Tube Mil/ Pebble Mill
It uses coarse particles as the grinding medium. Grinding is achieved by the action of ore particles of different sizes hit each other when the tumbling mill is rotated.
Autogenous Mill (AG Mill)
A variation of the AG mill that uses a combination of the ore and reduced charge of balls or rods as grinding medium to overcome difficulties in AG Mills. This is an economical option and is used in base and noble metals.
Semi-autogenous Mills (SAG Mills)
A process where crushed particles are separated using a hard metallic screen having a perforated surface with a fixed dimension and uniform aperture.
Screening
_______ is judged by the recovery of desired size and misplaced material in each product.
Efficiency
It is used for primary screening for coarse materials installed for sizing the feed to the primary crusher
Grizzly
