Slurry
A slurry is, in general, a thick suspension of solids in a liquid.
Contents
Examples of slurries
Examples of slurries include:
- A mixture of water and cement to form concrete
- A mixture of water, gelling agent, and oxidizers used as an explosive
- A mixture of water and bentonite used to make slurry walls
- A mixture of wood pulp and water used to make paper
- A mixture of water and animal waste used as fertilizer
- Meat slurry, a food product
- An abrasive substance used in chemical-mechanical polishing, a semiconductor manufacturing process
- A mixture of ice crystals, water and freezing point depressant, called slurry ice
- A wet-process cement rawmix
- A mixture of water, ceramic powder and various additives (e.g., dispersant) used in the processing of ceramics.
- Bean slurry, a food product
- A mixture of water and a starch (normally corn starch) used in cooking to thicken liquids to make a Blancmange (pudding) or translucent sauce (gravy).
Slurry calculations
Determining solids fraction
To determine the percent solids (or solids fraction) of a slurry from the density of the slurry, solids and liquid[1]
- <math>\phi_{sl}=\frac{\rho_{s}(\rho_{sl} - \rho_{l})}{\rho_{sl}(\rho_{s} - \rho_{l})}</math>
where
- <math>\phi_{sl}</math> is the solids fraction of the slurry
- <math>\rho_{s}</math> is the solids density
- <math>\rho_{sl}</math> is the slurry density
- <math>\rho_{l}</math> is the liquid density
In aqueous slurries, as is common in mineral processing, the specific gravity of the species is typically used, and since <math>SG_{water}</math> is taken to be 1, this relation is typically written:
- <math>\phi_{sl}=\frac{\rho_{s}(\rho_{sl} - 1)}{\rho_{sl}(\rho_{s} - 1)}</math>
even though specific gravity with units tons/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
- <math>\phi_{sl}=\frac{M_{s}}{M_{sl}}</math>*100
therefore
- <math>M_{sl}=\frac{M_{s}}{\phi_{sl}}</math>
and
- <math>M_{s}+M_{l}=\frac{M_{s}}{\phi_{sl}}</math>
then
- <math>M_{l}=\frac{M_{s}}{\phi_{sl}}-M_{s}</math>
and therefore
- <math>M_{l}=\frac{1-\phi_{sl}}{\phi_{sl}}M_{s}</math>
where
- <math>\phi_{sl}</math> is the solids fraction of the slurry
- <math>M_{s}</math> is the mass or mass flow of solids in the sample or stream
- <math>M_{sl}</math> is the mass or mass flow of slurry in the sample or stream
- <math>M_{l}</math> is the mass or mass flow of liquid in the sample or stream
Volumetric fraction from mass fraction
- <math>\phi_{sl,m}=\frac{M_{s}}{M_{sl}}</math>
Equivalently
- <math>\phi_{sl,v}=\frac{V_{s}}{V_{sl}}</math>
and in a minerals processing context where the specific gravity of the liquid (water) is taken to be one:
- <math>\phi_{sl,v}=\frac{\frac{M_{s}}{SG_{s}}}{\frac{M_{s}}{SG_{s}}+\frac{M_{l}}{1}}</math>
So
- <math>\phi_{sl,v}=\frac{M_{s}}{M_{s}+M_{l}SG_{s}}</math>
and
- <math>\phi_{sl,v}=\frac{1}{1+\frac{M_{l}SG_{s}}{M_{s}}}</math>
Then combining with the first equation:
- <math>\phi_{sl,v}=\frac{1}{1+\frac{M_{l}SG_{s}}{\phi_{sl,m}M_{s}}\frac{M_{s}}{M_{s}+M_{l}}}</math>
So
- <math>\phi_{sl,v}=\frac{1}{1+\frac{SG_{s}}{\phi_{sl,m}}\frac{M_{l}}{M_{s}+M_{l}}}</math>
Then since
- <math>\phi_{sl,m}=\frac{M_{s}}{M_{s}+M_{l}}=1-\frac{M_{l}}{M_{s}+M_{l}}</math>
we conclude that
- <math>\phi_{sl,v}=\frac{1}{1+SG_{s}(\frac{1}{\phi_{sl,m}}-1)}</math>
where
- <math>\phi_{sl,v}</math> is the solids fraction of the slurry on a volumetric basis
- <math>\phi_{sl,m}</math> is the solids fraction of the slurry on a mass basis
- <math>M_{s}</math> is the mass or mass flow of solids in the sample or stream
- <math>M_{sl}</math> is the mass or mass flow of slurry in the sample or stream
- <math>M_{l}</math> is the mass or mass flow of liquid in the sample or stream
- <math>SG_{s}</math> is the bulk specific gravity of the solids
See also
40x40px | Look up slurry in Wiktionary, the free dictionary. |
References
Cite error: Invalid <references>
tag;
parameter "group" is allowed only.
<references />
, or <references group="..." />
- ↑ Wills, B.A. and Napier-Munn, T.J, Wills' Mineral Processing Technology: an introduction to the practical aspects of ore treatment and mineral recovery, ISBN 978-0-7506-4450-1, Seventh Edition (2006), Elsevier, Great Britain