Perlite

PerlitePerlite in the natural state is a dense, glassy rock formed by volcanic action. When crushed and treated under proper conditions, it pops like popcorn, expanding to 20 or more times its original volume. A special milling and classification process gives Dicalite® perlite filter aids the structure and correct particle size range distribution needed for optimum performance.

Perlite is an amorphous mineral consisting of fused sodium potassium aluminium silicate. Dicalite® perlite filter aids are processed at temperatures exceeding 800 °C (1500 °F) which eliminates organic matter. They have extremely low solubility’s in mineral and organic acids at both low and high temperatures.

Solubility’s in strong alkalis will vary according to temperature and time of contact. Dicalite® perlite filter aids do not impart taste or odour to liquids being filtered.

A major advantage of Dicalite® perlite filter aids is that most weigh less per unit volume than standard diatomite filter aids. Pound for pound, this gives up to 20% greater filtering capacity resulting in comparable savings in filter aid usage, especially on rotary vacuum pre-coat filters.


Physical Properties
CharacteristicValue
Rock structuresClassical perlite
ColourGrey
Bulk Density900 – 1100 kg/m3
Moisturemax. 1 %
pH6 – 8.5

Typical Chemical Composition Perlite
Major ElementsTypical Range in %
SiO272
Al2O214
Fe2O30.7
Na2O4
K2O8.8
CaO0.3
MgO0.1
TiO0.1

Softening point890 – 1100 °C

Typical Values After Expansion
CharacteristicValue
Loose Weight Density35 – 45 kg/m3
Tamped Weight Density55 – 60 kg/m3
ColourWhite
Free Quartz< 0.5 %
Mechanical Resistance0.6 – 1.51 kg/cm2/cm
Thermal Conductivity λs =0.034 – 0.042 W/(m.K)
Fusion point1280 – 1350 °C
Specific heat0.20
Specific gravity2.2 – 2.4
Fire resistancePerlite is non-combustible

Typical Properties Dicalite® Perlite Filter Aids
ProductPFRv min.PFRv max.PCD min.PCD max.Float max.Pkg net kgData Sheet nr.
4082021.1tr.20/250
418204526220/251
428305518.1420/252
438507011.515.6620/253
4486511015.2816/18/224
4786011012.515.21020/255
41087012012.515.21220/256
41287515012.72516/20/227
41589016511.013.63016/20/258
420812518011.34516/209
425814021010.47014/1810
4258-S215022010.27514/1811
430817523510.07514/1812
435820026010.08014/1813
440822030010.08014/1814

Notes

Permeability Flowrate (PFRv)

  • The constant volume filtration flowrate is measured by the permeability method (S.T.M. Nr. I-9).
  • This relative value gives an idea of the filtration speed.
  • It is the fundamental characteristic which differentiates one filteraid grade from another when the particles are formed into a filter bed or cake. Permeability is related to particle size distribution.

Permeability Cake Density (PCD)

  • The wet cake density is also measured by the permeability method (S.T.M. Nr. I-9).
  • This value gives the wet cake density in lbs/ft³ (x16 » kg/m³).
  • Perlite filteraids form lower density cakes than diatomite filteraids of comparable permeabilities. Densities of Dicalite® perlite filteraids are controlled at a level found to be optimum for most effective performance.

Float

  • The float is measured by S.T.M. Nr. O-4
  • This value gives the amount of floating particles in ml/20g

Perlite Functional Fillers

Dicalite® perlite functional fillers are a versatile family of mineral-based silicate products available throughout the world. A specialised Dicalite® process incorporating expansion, selective milling, and sizing determines the particle shape of each filler product. A variety of flake or di-, tri-, and tetrahedral particle shapes are obtained by this exclusive process. These unique shapes provide numerous functions including high surface area, permeability and reinforcement and have densities among the lowest of any of the mineral fillers. In addition to superior spatial loading, this property affords customers the added bonus of density control in their finished products. Dicalite® perlite fillers are off-white and do not interfere with the colouring of the products into which they are formulated.

Dicalite® perlite fillers are inert to all but strong acids or alkalis and have no residual surface reactivity. After processing they are free of any organic contamination.

Dicalite® offers several grades of perlite functional fillers, the most popular of which are described in the table below.


Typical Properties Dicalite® Perlite Functional Fillers
ProductScreen An.* 325 (%)Screen An.* 140 (%)PCD min.PCD max.Float max.Pkg net kgPkg length (cm)Pkg colourData Sheet nr.
GPE-082-50-121.1trace20/25100/110red0G
GPE-182-50-126220/25100/110red1G
GPE-282-120-118.1420/25100/110red2G
GPE-382-150-311.515.6620/25100/110red3G
GPE-485-200-515.2816/18/22100/110green4G
GPE-7810-252-712.515.21020/25100/110yellow5G
GPE-10810-354-812.515.21220/25100/110yellow6G
GPE-12815-407-3112.72516/20/22100/110yellow7G
GPE-15815-457-3111.013.63016/20/25100/110yellow8G
GPE-20820-5013-2511.34516/20100/110yellow9G
GPE-25830-5518-2510.47014/18100/110yellow10G
GPE-258 S235-6018-3010.27514/18100/110yellow11G
GPE-30840-7020-3510.07514/18100/110yellow12G
GPE-35860-7530-4510.08014/18100/110yellow13G
GPE-40860-8030-5010.08014/18100/110yellow14G

* Retained on U.S. Std. Sieve 325 Mesh = 0.044 mm, 140 Mesh = 0.105 mm (wet screening).