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 (American and British English spelling differences#-re, -er, international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American and British English spelling differences# ...
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 mixe ...
, 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 crud ...
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
A thickening agent or thickener is a substance which can increase the viscosity of a liquid without substantially changing its other properties. Edible thickeners are commonly used to thicken sauces, soups, and puddings without altering the ...
, 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 lahar (, from jv, ꦮ꧀ꦭꦲꦂ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley.
Lahars are extr ...
*A mixture of
bentonite and water used to make
slurry walls
*
Coal slurry, a mixture of
coal waste 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 pa ...
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 process plant where petroleum (crude oil) is transformed and refined into useful products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, liq ...
. 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, rags, grasses or other vegetable sources in water, draining the water through fine mesh leaving the fibre evenly distribu ...
*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
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 19t ...
*A
bolus of chewed food mixed with
saliva
Saliva (commonly referred to as spit) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which DNA can ...
*A mixture of epoxy glue and
glass microspheres 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 at its dens ...
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 sect ...
*
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 ...
*
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 fly ...
*
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.
{{Authority control
Environmental engineering
Materials