A mill is a device, often a
structure
A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as ...
,
machine
A machine is a physical system using Power (physics), power to apply Force, forces and control Motion, movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to na ...
or
kitchen appliance
A home appliance, also referred to as a domestic appliance, an electric appliance or a household appliance, is a machine which assists in household functions such as cooking, cleaning and food preservation.
Appliances are divided into three ty ...
, that breaks
solid
Solid is one of the State of matter#Four fundamental states, four fundamental states of matter (the others being liquid, gas, and Plasma (physics), plasma). The molecules in a solid are closely packed together and contain the least amount o ...
materials into smaller pieces by grinding, crushing, or cutting. Such
comminution
Comminution is the reduction of solid materials from one average particle size to a smaller average particle size, by crushing, grinding, cutting, vibrating, or other processes. In geology, it occurs naturally during faulting in the upper part of ...
is an important
unit operation
In chemical engineering and related fields, a unit operation is a basic step in a process. Unit operations involve a physical change or chemical transformation such as separation, crystallization, evaporation, filtration, polymerization, isomerizat ...
in many
processes. There are many different types of mills and many types of materials processed in them. Historically mills were powered by hand or by animals (e.g., via a
hand crank
A crank is an arm attached at a right angle to a rotating shaft by which circular motion is imparted to or received from the shaft. When combined with a connecting rod, it can be used to convert circular motion into reciprocating motion, or vice ...
),
working animal
A working animal is an animal, usually domesticated, that is kept by humans and trained to perform tasks instead of being slaughtered to harvest animal products. Some are used for their physical strength (e.g. oxen and draft horses) or for t ...
(e.g.,
horse mill
A horse mill is a mill, sometimes used in conjunction with a watermill or windmill, that uses a horse engine as the power source. Any milling process can be powered in this way, but the most frequent use of animal power in horse mills was for grin ...
), wind (
windmill
A windmill is a structure that converts wind power into rotational energy using vanes called windmill sail, sails or blades, specifically to mill (grinding), mill grain (gristmills), but the term is also extended to windpumps, wind turbines, and ...
) or water (
watermill
A watermill or water mill is a mill that uses hydropower. It is a structure that uses a water wheel or water turbine to drive a mechanical process such as milling (grinding), rolling, or hammering. Such processes are needed in the production of ...
). In modern era, they are usually powered by
electricity
Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described ...
.
The grinding of solid materials occurs through mechanical forces that break up the structure by overcoming the interior bonding forces. After the grinding the state of the solid is changed: the grain size, the grain size disposition and the grain shape.
Milling also refers to the process of breaking down, separating, sizing, or classifying aggregate material (e.g. mining
ore
Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April 2 ...
). For instance rock crushing or grinding to produce uniform aggregate size for construction purposes, or separation of rock, soil or aggregate material for the purposes of structural fill or land reclamation activities. Aggregate milling processes are also used to remove or separate contamination or moisture from aggregate or soil and to produce "dry fills" prior to transport or structural filling.
Grinding may serve the following purposes in engineering:
*increase of the surface area of a solid
*manufacturing of a solid with a desired grain size
*pulping of resources
Grinding laws
In spite of a great number of studies in the field of fracture schemes there is no formula known which connects the technical grinding work with grinding results. Mining engineers,
Peter von Rittinger
Peter Ritter von Rittinger or Peter von Rittinger (see styling variants at ''Ritter'') (23 January 1811 Nový Jičín / Neutitschein – 7 December 1872 Vienna) was an Austrian pioneer of mineral processing.
Life
After completion of legal stud ...
,
Friedrich Kick Friedrich may refer to:
Names
*Friedrich (surname), people with the surname ''Friedrich''
*Friedrich (given name), people with the given name ''Friedrich''
Other
*Friedrich (board game), a board game about Frederick the Great and the Seven Years' ...
and
Fred Chester Bond
Fred Chester Bond (June 10, 1899 – January 23, 1977) was an American mining engineer. A graduate of the Colorado School of Mines, he worked in the mining equipment and ore milling equipment business of Allis-Chalmers from 1930 to 1964.
Bond ...
independently developed equations relating produced equations to relate the needed grinding work to the grain size produced and a fourth engineer,
R.T.Hukki suggested that these three equations might each describe a narrow range of grain sizes and proposed uniting them along a single curve describing what has come to be known as the ''Hukki relationship''.
In stirred mills, the Hukki relationship does not apply and instead, experimentation has to be performed to determine any relationship.
To evaluate the grinding results the grain size disposition of the source material (1) and of the ground material (2) is needed. Grinding degree is the ratio of the sizes from the grain disposition. There are several definitions for this characteristic value:
*Grinding degree referring to grain size ''d''
80
:
:Instead of the value of ''d''
80 also ''d''
50 or other grain diameter can be used.
*Grinding degree referring to specific surface
:
:The specific surface area referring to volume ''S''
v and the specific surface area referring to mass ''S''
m can be found out through experiments.
*Pretended grinding degree
:
:The discharge die gap a of the grinding machine is used for the ground solid matter in this formula.
Grinding machines
In materials processing a grinder is a machine for producing fine particle size reduction through
attrition
Attrition may refer to
*Attrition warfare, the military strategy of wearing down the enemy by continual losses in personnel and material
**War of Attrition, fought between Egypt and Israel from 1968 to 1970
**War of attrition (game), a model of agg ...
and
compressive
In continuum mechanics, stress is a physical quantity. It is a quantity that describes the magnitude of forces that cause deformation. Stress is defined as ''force per unit area''. When an object is pulled apart by a force it will cause elonga ...
force
In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a p ...
s at the grain size level. See also
crusher
A crusher is a machine designed to reduce large rocks into smaller rocks, gravel, sand or rock dust.
Crushers may be used to reduce the size, or change the form, of waste materials so they can be more easily disposed of or recycled, or to reduce ...
for mechanisms producing larger particles. In general, grinding processes require a relatively large amount of energy; for this reason, an experimental method to measure the energy used locally during milling with different machines was recently proposed.
Autogenous mill
Autogenous or autogenic mills are so-called due to the self-grinding of the ore: a rotating drum throws larger rocks of ore in a cascading motion which causes impact breakage of larger rocks and compressive grinding of finer particles. It is similar in operation to a SAG mill as described below but does not use steel balls in the mill. Also known as ROM or "Run Of Mine" grinding.
Ball mill
A typical type of fine grinder is the
ball mill
A ball mill is a type of grinder used to grind or blend materials for use in mineral dressing processes, paints, pyrotechnics, ceramics, and selective laser sintering. It works on the principle of impact and attrition: size reduction is done ...
. A slightly inclined or horizontal rotating cylinder is partially filled with
ball
A ball is a round object (usually spherical, but can sometimes be ovoid) with several uses. It is used in ball games, where the play of the game follows the state of the ball as it is hit, kicked or thrown by players. Balls can also be used f ...
s, usually
stone
In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition, and the way in which it is formed. Rocks ...
or
metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typicall ...
, which grind material to the necessary fineness by
friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction:
*Dry friction is a force that opposes the relative lateral motion of t ...
and impact with the tumbling balls. Ball mills normally operate with an approximate ball charge of 30%. Ball mills are characterized by their smaller (comparatively) diameter and longer length, and often have a length 1.5 to 2.5 times the diameter. The feed is at one end of the cylinder and the discharge is at the other. Ball mills are commonly used in the manufacture of
Portland cement
Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th c ...
and finer grinding stages of mineral processing. Industrial ball mills can be as large as 8.5 m (28 ft) in diameter with a 22 MW motor, drawing approximately 0.0011% of the total world's power (see
List of countries by electricity consumption
This list of countries by electric energy consumption is mostly based on the Energy Information Administration.
Several non-sovereign entities are also included for information purposes, with their parent state noted.
The per capita data for many ...
). However, small versions of ball mills can be found in laboratories where they are used for grinding sample material for quality assurance.
The power predictions for ball mills typically use the following form of the Bond equation:
[Mineral Beneficiation – The Third Theory of Comminution – Document Summary](_blank)
Onemine.org. Retrieved on 2010-10-09.
:
where
* ''E'' is the energy (kilowatt-hours per metric or short ton)
* ''W'' is the work index measured in a laboratory ball mill (kilowatt-hours per metric or short ton)
* ''P
80'' is the mill circuit product size in micrometers
* ''F
80'' is the mill circuit feed size in micrometers.
Buhrstone mill
Another type of fine grinder commonly used is the
French buhrstone
Millstones or mill stones are stones used in gristmills, for grinding wheat or other grains. They are sometimes referred to as grindstones or grinding stones.
Millstones come in pairs: a convex stationary base known as the ''bedstone'' and ...
mill, which is similar to old-fashioned
flour mill
A gristmill (also: grist mill, corn mill, flour mill, feed mill or feedmill) grinds cereal grain into flour and middlings. The term can refer to either the grinding mechanism or the building that holds it. Grist is grain that has been separat ...
s.
High pressure grinding rolls
A high pressure grinding roll, often referred to as HPGRs or roller press, consists out of two rollers with the same dimensions, which are rotating against each other with the same circumferential speed. The special feeding of bulk material through a hopper leads to a material bed between the two rollers. The bearing units of one roller can move linearly and are pressed against the material bed by springs or hydraulic cylinders. The pressures in the material bed are greater than 50 MPa (7,000
PSI
Psi, PSI or Ψ may refer to:
Alphabetic letters
* Psi (Greek) (Ψ, ψ), the 23rd letter of the Greek alphabet
* Psi (Cyrillic) (Ѱ, ѱ), letter of the early Cyrillic alphabet, adopted from Greek
Arts and entertainment
* "Psi" as an abbreviatio ...
). In general they achieve 100 to 300 MPa. By this the material bed is compacted to a solid volume portion of more than 80%.
The roller press has a certain similarity to roller crushers and roller presses for the compacting of powders, but purpose, construction and operation mode are different.
Extreme
pressure
Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...
causes the particles inside of the compacted material bed to
fracture
Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...
into finer particles and also causes microfracturing at the grain size level. Compared to ball mills HPGRs achieve a 30 to 50% lower specific energy consumption, although they are not as common as ball mills since they are a newer technology.
A similar type of intermediate crusher is the edge runner, which consists of a circular pan with two or more heavy
wheel
A wheel is a circular component that is intended to rotate on an axle Bearing (mechanical), bearing. The wheel is one of the key components of the wheel and axle which is one of the Simple machine, six simple machines. Wheels, in conjunction wi ...
s known as mullers rotating within it; material to be crushed is shoved underneath the wheels using attached
plow
A plough or plow ( US; both ) is a farm tool for loosening or turning the soil before sowing seed or planting. Ploughs were traditionally drawn by oxen and horses, but in modern farms are drawn by tractors. A plough may have a wooden, iron or ...
blades.
Pebble mill
A rotating drum causes friction and attrition between rock
pebble
A pebble is a clast of rock with a particle size of based on the Udden-Wentworth scale of sedimentology. Pebbles are generally considered larger than granules ( in diameter) and smaller than cobbles ( in diameter). A rock made predominant ...
s and ore particles. May be used where product contamination by
iron
Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
from
steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...
balls must be avoided. Quartz or silica is commonly used because it is inexpensive to obtain.
Rod mill
A rotating drum causes friction and attrition between steel
rods and ore particles. But note that the term 'rod mill' is also used as a synonym for a
slitting mill
The slitting mill was a watermill for slitting bars of iron into rods. The rods then were passed to nailers who made the rods into nails, by giving them a point and head.
The slitting mill was probably invented near Liège in what is now Belg ...
, which makes rods of iron or other metal. Rod mills are less common than ball mills for grinding minerals.
The rods used in the mill, usually a high-carbon steel, can vary in both the length and the diameter. However, the smaller the rods, the larger is the total surface area and hence, the greater the grinding efficiency
SAG mill
SAG is an acronym for semi-autogenous grinding. SAG mills are autogenous mills that also use grinding balls like a ball mill. A SAG mill is usually a primary or first stage grinder. SAG mills use a ball charge of 8 to 21%. The largest SAG mill is 42' (12.8m) in diameter, powered by a 28 MW (38,000 HP) motor. A SAG mill with a 44' (13.4m) diameter and a power of 35 MW (47,000 HP) has been designed.
Gearless mill drives
abb.com
Attrition between grinding balls and ore particles causes grinding of finer particles. SAG mills are characterized by their large diameter and short length as compared to ball mills. The inside of the mill is lined with lifting plates to lift the material inside the mill, where it then falls off the plates onto the rest of the ore charge. SAG mills are primarily used at gold, copper and platinum mines with applications also in the lead, zinc, silver, alumina and nickel industries.
Tower mill
Tower mills, often called vertical mills, stirred mills or regrind mills, are a more efficient means of grinding material at smaller particle sizes, and can be used after ball mills in a grinding process. Like ball mills, grinding (steel) balls or pebbles are often added to stirred mills to help grind ore, however these mills contain a large screw mounted vertically to lift and grind material. In tower mills, there is no cascading action as in standard grinding mills. Stirred mills are also common for mixing quicklime (CaO) into a lime slurry. There are several advantages to the tower mill: low noise, efficient energy usage, and low operating costs.
Vertical shaft impactor mill (VSI mill)
A VSI mill throws rock or ore particles against a wear plate by slinging them from a spinning center that rotates on a vertical shaft. This type of mill uses the same principle as a VSI crusher.
Types of grinding mills
* Windmill
A windmill is a structure that converts wind power into rotational energy using vanes called windmill sail, sails or blades, specifically to mill (grinding), mill grain (gristmills), but the term is also extended to windpumps, wind turbines, and ...
, wind powered
* Watermill
A watermill or water mill is a mill that uses hydropower. It is a structure that uses a water wheel or water turbine to drive a mechanical process such as milling (grinding), rolling, or hammering. Such processes are needed in the production of ...
, water powered
* Horse mill
A horse mill is a mill, sometimes used in conjunction with a watermill or windmill, that uses a horse engine as the power source. Any milling process can be powered in this way, but the most frequent use of animal power in horse mills was for grin ...
, animal powered
* Treadwheel
A treadwheel, or treadmill, is a form of engine typically powered by humans. It may resemble a water wheel in appearance, and can be worked either by a human treading paddles set into its circumference (treadmill), or by a human or animal standing ...
, human powered (archaic: "treadmill")
* Ship mill
A ship mill, more commonly known as a boat mill is a type of watermill. The milling and grinding technology and the drive (waterwheel) are built on a floating platform on this type of mill.
"Deutsches Museum: Ship Mill",
The Deutsches Museum' ...
, floats near a river bank or bridge
*Arrastra
An arrastra (or arastra) is a primitive mill for grinding and pulverizing (typically) gold or silver ore. Its simplest form is two or more flat-bottomed drag stones placed in a circular pit paved with flat stones, and connected to a center post ...
, simple mill for grinding and pulverizing (typically) gold or silver ore.
* Roller mill
Roller mills are mills that use cylindrical rollers, either in opposing pairs or against flat plates, to crush or grind various materials, such as grain, ore, gravel, plastic, and others. Roller grain mills are an alternative to traditiona ...
, an equipment for the grinding or pulverizing of grain and other raw materials using cylinders
* Stamp mill
A stamp mill (or stamp battery or stamping mill) is a type of mill machine that crushes material by pounding rather than grinding, either for further processing or for extraction of metallic ores. Breaking material down is a type of unit operatio ...
, a specialized machine for reducing ore to powder for further processing or for fracturing other materials
* A place of business for making articles of manufacture. The term mill was once in common use for a factory because many factories in the early stages of the Industrial Revolution were powered by a watermill, but nowadays it is only used in a few specific contexts; e.g.,
** Bark mill
Bark mills, also known as Catskill's mills, are water, steam, horse, ox or wind-powered edge mills used to process the bark, roots, and branches of various tree species into a fine powder known as tanbark, used for tanning leather. This powderin ...
produces tanbark for tanneries
** Cider mill
A cider mill, also known as a cidery, is the location and equipment used to crush apples into apple juice for use in making apple cider, hard cider, applejack, apple wine, pectin and other products derived from apples. More specifically, it refe ...
crushes apples to give cider
** Gristmill
A gristmill (also: grist mill, corn mill, flour mill, feed mill or feedmill) grinds cereal grain into flour and Wheat middlings, middlings. The term can refer to either the Mill (grinding), grinding mechanism or the building that holds it. Grist i ...
grinds grain into flour
** Oil mill
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturated ...
, see expeller pressing
Expeller pressing (also called oil pressing) is a mechanical method for extracting oil from raw materials. The raw materials are squeezed under high pressure in a single step. When used for the extraction of food oils, typical raw materials are ...
, extrusion
Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex c ...
** Paper mill
A paper mill is a factory devoted to making paper from vegetable fibres such as wood pulp, old rags, and other ingredients. Prior to the invention and adoption of the Fourdrinier machine and other types of paper machine that use an endless belt, ...
produces paper
** Sawmill
A sawmill (saw mill, saw-mill) or lumber mill is a facility where logs are cut into lumber. Modern sawmills use a motorized saw to cut logs lengthwise to make long pieces, and crosswise to length depending on standard or custom sizes (dimensi ...
cuts timber
** Starch mill
Starch or amylum is a polymeric carbohydrate consisting of numerous glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants for energy storage. Worldwide, it is the most common carbohydrate in human diet ...
** Steel mill
A steel mill or steelworks is an industrial plant for the manufacture of steel. It may be an integrated steel works carrying out all steps of steelmaking from smelting iron ore to rolled product, but may also be a plant where steel semi-finish ...
manufactures steel
** Sugar mill (also called a sugar refinery
A sugar refinery is a refinery which processes raw sugar from cane or beets into white refined sugar.
Many cane sugar mills produce raw sugar, which is sugar that still contains molasses, giving it more colour (and impurities) than the white ...
) processes sugar beets or sugar cane into various finished products
** Textile mill
Textile Manufacturing or Textile Engineering is a major industry. It is largely based on the conversion of fibre into yarn, then yarn into fabric. These are then dyed or printed, fabricated into cloth which is then converted into useful goods ...
*** Silk mill
A silk mill is a factory that makes silk for garments using a process called silk throwing. Traditionally, silk mills were concentrated in Japan, England, New Jersey, Pennsylvania, Italy and Switzerland.
The silk throwing process
Silk is a natur ...
, for silk
*** Flax mill
Flax mills are mills which process flax. The earliest mills were developed for spinning yarn for the linen industry.
John Kendrew (an optician) and Thomas Porthouse (a clockmaker), both of Darlington developed the process from Richard Arkwrigh ...
, for flax
*** Cotton mill
A cotton mill is a building that houses spinning (textiles), spinning or weaving machinery for the production of yarn or cloth from cotton, an important product during the Industrial Revolution in the development of the factory system.
Althou ...
, for cotton
** Huller
A rice huller or rice husker is an agricultural machine used to automate the process of removing the chaff (the outer husks) of grains of rice. Throughout history, there have been numerous techniques to hull rice. Traditionally, it would be po ...
(also called a rice mill, or rice husker) is used to hull rice
** Powder mill
A powder mill was a mill where gunpowder is made from sulfur, saltpeter and charcoal.
Milling steps
Crude grinding and mixing operations such as the Frankford Powder-Mill of Philadelphia were a cottage industry until the industrial revolution ...
produces gunpowder
*Ball mill
A ball mill is a type of grinder used to grind or blend materials for use in mineral dressing processes, paints, pyrotechnics, ceramics, and selective laser sintering. It works on the principle of impact and attrition: size reduction is done ...
*Bead mill
A bead is a small, decorative object that is formed in a variety of shapes and sizes of a material such as stone, bone, shell, glass, plastic, wood, or pearl and with a small hole for threading or stringing. Beads range in size from under ...
* Coffee mill
*Colloid mill A colloid mill is a machine that is used to reduce the particle size of a solid in suspension in a liquid, or to reduce the droplet size in emulsions. Colloid mills work on the rotor-stator principle: a rotor turns at high speeds (2000 - 18000 RPM ...
*Conical mill A conical mill (or conical screen mill) is a machine used to reduce the size of material in a uniform manner. It is an alternative to the hammermill or other forms of grinding mills. As the name implies, the conical mill varies in diameter from wher ...
*Disintegrator
A raygun is a science-fiction directed-energy weapon that releases energy, usually with destructive effect.Jeff Prucher, '' Brave New Words: The Oxford Dictionary of Science Fiction,'' Oxford University Press, 2007, page 162 They have vario ...
* Disk mill
*Edge mill
An edge mill is a mill used for crushing or grinding in which stones roll around on their edges on a level circular bed. They were developed in China in the third century and are still used today in remote villages around the world. When the mill ...
*Gristmill
A gristmill (also: grist mill, corn mill, flour mill, feed mill or feedmill) grinds cereal grain into flour and Wheat middlings, middlings. The term can refer to either the Mill (grinding), grinding mechanism or the building that holds it. Grist i ...
, also called flour mill or corn mill
*Hammermill
A hammer mill is a mill whose purpose is to shred or crush aggregate material into smaller pieces by the repeated blows of little hammers. These machines have numerous industrial applications, including:
* Ethanol plants (grains)
* A farm machi ...
* IsaMill
*Jet mill
A jet mill grinds materials by using a high speed jet of compressed air or inert gas to impact particles into each other. Jet mills can be designed to output particles below a certain size while continuing to mill particles above that size, res ...
*Mortar and pestle
Mortar and pestle is a set of two simple tools used from the Stone Age to the present day to prepare ingredients or substances by crushing and grinding them into a fine paste or powder in the kitchen, laboratory, and pharmacy. The ''mortar'' () ...
*Pellet mill
A pellet mill, also known as a pellet press, is a type of mill or machine press used to create pellets from powdered material. Pellet mills are unlike grinding mills, in that they combine small materials into a larger, homogeneous mass, rather tha ...
* Planetary mill
* Stirred mill
* Three roll mill
* Vibratory mill
*VSI mill
A VSI mill (vertical shaft impactor mill) is a mill that comminutes particles of material into smaller (finer) particles by throwing them against a hard surface inside the mill (called the wear plate). Any hard or friable materials can be ground w ...
*Wiley mill
Wiley mill refers to a specific group of grinding mills manufactured under the name Thomas Scientific. The term Wiley as it relates to cutting or grinding mills is a registered trademark of Arthur H. Thomas Company. These mills prepare materials fo ...
See also
*Burr grinder
A burr mill, or burr grinder, is a mill used to grind hard, small food products between two revolving abrasive surfaces separated by a distance usually set by the user. When the two surfaces are set far apart, the resulting ground material is co ...
*Coffee grinder
A burr mill, or burr grinder, is a mill used to grind hard, small food products between two revolving abrasive surfaces separated by a distance usually set by the user. When the two surfaces are set far apart, the resulting ground material is co ...
*Expeller
Expeller pressing (also called oil pressing) is a mechanical method for extracting oil
An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) & lipophilic (mixes w ...
*Extruder
Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex ...
*Herb grinder
An herb grinder (or simply, a grinder) is a cylindrical device with two halves (top and bottom) that separate and have sharp teeth or pegs aligned in such a way that when both halves are turned, material inside is shredded. Though the manufac ...
*Millstone
Millstones or mill stones are stones used in gristmills, for grinding wheat or other grains. They are sometimes referred to as grindstones or grinding stones.
Millstones come in pairs: a convex stationary base known as the ''bedstone'' and ...
* Rock crusher
* IsaMill
References
External links
*
Video of fine grinder in mining application
Flour Mill Details
Image of SAG mill during installation
Grinding Media
Grinding Media Guide
{{Authority control
Mining equipment