A slurry is a mixture of denser solids suspended in liquid, usually water. The most common use of slurry is as a means of transporting solids or separating minerals, the liquid being a carrier that is pumped on a device such as a
centrifugal pump. The size of solid particles may vary from 1
micrometre
The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer ( American spelling), also commonly known as a micron, is a unit of length in the International System of ...
up to hundreds of
millimetres.
The particles may settle below a certain transport velocity and the mixture can behave like a
Newtonian or
non-Newtonian fluid. Depending on the mixture, the slurry may be abrasive and/or corrosive.
Examples
Examples of slurries include:
*Cement slurry, a mixture of
cement
A cement is a binder, a chemical substance used for construction that sets, hardens, and adheres to other materials to bind them together. Cement is seldom used on its own, but rather to bind sand and gravel (aggregate) together. Cement m ...
, water, and assorted dry and liquid additives used in the
petroleum
Petroleum, also known as crude oil, or simply oil, is a naturally occurring yellowish-black liquid mixture of mainly hydrocarbons, and is found in geological formations. The name ''petroleum'' covers both naturally occurring unprocessed crude ...
and other industries
*Soil/cement slurry, also called Controlled Low-Strength Material (CLSM), flowable fill, controlled density fill, flowable mortar, plastic soil-cement, K-Krete, and other names
*A mixture of
thickening agent, oxidizers, and water used to form a
gel explosive
*A mixture of
pyroclastic
Pyroclastic rocks (derived from the el, πῦρ, links=no, meaning fire; and , meaning broken) are clastic rocks composed of rock fragments produced and ejected by explosive volcanic eruptions. The individual rock fragments are known as pyroc ...
material, rocky debris, and water produced in a
volcanic eruption and known as a
lahar
*A mixture of
bentonite
Bentonite () is an absorbent swelling clay consisting mostly of montmorillonite (a type of smectite) which can either be Na-montmorillonite or Ca-montmorillonite. Na-montmorillonite has a considerably greater swelling capacity than Ca-m ...
and water used to make
slurry walls
*
Coal slurry, a mixture of
coal waste
Coal refuse (also described as coal waste, rock, slag, coal tailings, waste material, rock bank, culm, boney, or gob) is the material left over from coal mining, usually as tailings piles or spoil tips. For every tonne of hard coal generated by mi ...
and water, or crushed coal and water
*
Slip, a mixture of
clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4).
Clays develop plasticity when wet, due to a molecular film of water surrounding the clay part ...
and water used for joining, glazing and decoration of ceramics and pottery.
*
Slurry oil, the highest boiling fraction distilled from the effluent of an
FCC unit in an
oil refinery
An oil refinery or petroleum refinery is an industrial processes, industrial process Factory, plant where petroleum (crude oil) is transformed and refining, refined into useful products such as gasoline (petrol), diesel fuel, asphalt, asphalt ...
. It contains a large amount of catalyst, in form of sediments hence the denomination of slurry.
*A mixture of wood pulp and water used to make
paper
Paper is a thin sheet material produced by mechanically or chemically processing cellulose fibres derived from wood, Textile, rags, poaceae, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre e ...
*Manure slurry, a mixture of animal waste, organic matter, and sometimes water often known simply as "slurry" in
agricultural
Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled peopl ...
use, used as
fertilizer
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
after aging in a
slurry pit
*
Meat slurry, a mixture of finely ground meat and water, centrifugally dewatered and used as a food ingredient.
*An abrasive substance used in
chemical-mechanical polishing
*
Slurry ice, a mixture of ice crystals, freezing point depressant, and water
*A mixture of raw materials and water involved in the
rawmill manufacture of
Portland cement
*A
bolus
Bolus may refer to:
Geography
* Bolus, Iran, a village in Ardabil Province, Iran
* Bolus, or Baulus, an Anatolian village on the site of ancient Berissa
Medicine
* Bolus (digestion), a ball-shaped mass moving through the digestive tract
* Bolus ...
of chewed food mixed with
saliva
*A mixture of epoxy glue and
glass microsphere
Glass microspheres are microscopic spheres of glass manufactured for a wide variety of uses in research, medicine, consumer goods and various industries. Glass microspheres are usually between 1 and 1000 micrometers in diameter, although the ...
s used as a filler compound around core materials in
sandwich-structured composite airframes.
Calculations
Determining solids fraction
To determine the percent solids (or solids fraction) of a slurry from the density of the slurry, solids and liquid
[Wills, B.A. and Napier-Munn, T.J, ''Wills' Mineral Processing Technology: an introduction to the practical aspects of ore treatment and mineral recovery, '', Seventh Edition (2006), Elsevier, Great Britain]
:
where
:
is the solids fraction of the slurry (state by mass)
:
is the solids density
:
is the slurry density
:
is the liquid density
In aqueous slurries, as is common in mineral processing, the specific gravity of the species is typically used, and since
specific gravity
Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...
of water is taken to be 1, this relation is typically written:
:
even though specific gravity with units tonnes/m
3 (t/m
3) is used instead of the SI density unit, kg/m
3.
Liquid mass from mass fraction of solids
To determine the mass of liquid in a sample given the mass of solids and the mass fraction:
By definition
:
therefore
:
and
:
then
:
and therefore
:
where
:
is the solids fraction of the slurry
:
is the mass or mass flow of solids in the sample or stream
:
is the mass or mass flow of slurry in the sample or stream
:
is the mass or mass flow of liquid in the sample or stream
Volumetric fraction from mass fraction
:
Equivalently
:
and in a minerals processing context where the specific gravity of the liquid (water) is taken to be one:
:
So
:
and
:
Then combining with the first equation:
:
So
:
Then since
:
we conclude that
:
where
:
is the solids fraction of the slurry on a ''volumetric'' basis
:
is the solids fraction of the slurry on a ''mass'' basis
:
is the mass or mass flow of solids in the sample or stream
:
is the mass or mass flow of slurry in the sample or stream
:
is the mass or mass flow of liquid in the sample or stream
:
is the bulk specific gravity of the solids
See also
*
Grout
Grout is a dense fluid which hardens to fill gaps or used as reinforcement in existing structures. Grout is generally a mixture of water, cement and sand, and is employed in pressure grouting, embedding rebar in masonry walls, connecting sec ...
*
Slurry pipeline
A slurry pipeline is a specially engineered pipeline used to move ores, such as coal or iron, or mining waste, called tailings, over long distances. A mixture of the ore concentrate and water, called slurry, is pumped to its destination and the wa ...
*
Slurry transport Slurry transport uses several methods: hydraulic conveying; conventional lean slurry conveying; and high concentration slurry disposal (HCSD). The latter, HCSD, is a relatively modern approach, which is used to transfer high throughputs of fine f ...
*
Slurry wall
References
External links
*Bonapace, A.C
A General Theory of the Hydraulic Transport of Solids in Full Suspension*
*Ming, G., Ruixiang, L., Fusheng, N., Liqun, X. (2007)
Hydraulic Transport of Coarse Gravel—A Laboratory Investigation Into Flow Resistance.
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