Silica Support Gravel

Silica Gravel is a hard, different-colored, and round shaped.  

Gravel is mined, washed, and sieved to minimum / maximum grain sizes that meet or exceed international standards such as AWWA B100-1 or EN12904.

Gravel is used as a support layer to prevent migration of filter media through filter floor. Gravel does not contribute to removal of suspended particles.

Gravel is arranged in hour-glass configuration where the retaining layer is placed in the middle of the support gravel layers. The grain size of support gravel largest size prevents filter floor blinding. The same arrangement is placed in reverse order above and below the retaining layer to prevent upset of support gravel and hence cause migration of filter media.

Retention layer prevents fine filter media from migrating through support gravel and hence filter floor. It is sized to be 2.5 of the smallest media size.

Gravel is sieved to maximum and minimum size. Due to its complex shape, it is misleading to use uniformity coefficient (UC), especially in large sizes. 

  • Acid Solubility is tested in 10% HCl solution for 24 hours. 
  • Attrition loss is calculated on basis of 100 hours of backwash
Specific Gravity:c. 2.6 
Bulk Density:1.45 – 1.65Ton/m³
Hardness:> 7 Moh
Acid Solubility:2.5 – 5.0%
Colour:Mixed Colour 
Attrition Loss:Negligible 

 

SiO2

:

84% – 89%
Fe2O3

:

< 2.5 %
Al2O3

:

<1.50 %
Moisture

:

< 2.0 %

  • EN12904 / AWWA B100 requires media specification either as size range, UC and over/under size or Effective Size and UC. 
  • The size range (0.4 – 0.8) and (0.5 – 1.0) are mostly chosen for water treatment application as good balance of size, head loss characteristics and expansion at reasonable backwash velocity. 
  • We offer other sizes on request 
1.1.4 – 2.8mm
2.2.80 – 6.0mm
3.6.0 – 12.0mm
4.12.0 – 19.0mm
  • Desalination pre-treatment filtration systems
  • Surface water filtration
  • Well water filtration systems
  • Wastewater tertiary filtration
  • Industrial filtration systems
  • Swimming pools filters

Physical Properties

Chemical Properties

Applications

Specific Gravity

:

c 2.65

 

Bulk Density

:

1.45 – 1.65

TON/m³

Hardness

:

5 – 7

Moh

Acid Solubility

:

2.5 – 5.0

% 

Colour

:

Mixed Colour

 

Attrition Loss

:

Negligible

% 

 

SiO2

:

84% – 89%
Fe2O3

:

< 2.5 %
Al2O3

:

< 1.5 %
Moisture

:

< 2%

  • Desalination pre-treatment filtration systems
  • Lime contact tanks
  • Surface water filtration
  • Well water filtration systems
  • Wastewater tertiary filtration
  • Industrial filtration systems
  • Swimming pools filters

Standard Grain Size (range)

1.2.4 – 1.2mm
2.6.0 – 2.8mm
3.12.0 – 6.0mm
4.19.0 – 12.0mm
   

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