Silica Sand
- Silica (SiO2) sand is easily obtainable on beaches, and manufacturers commonly use it to make glass. People usually crush sandstone or collect it from rivers and beaches. The purest form of silica has a fusion point of 1,760°C (3,200°F). However, impurities lower the melting point of sands used to extract silica.
- For high-melting-point casting like steel, one should use at least 98% pure silica. For lower-melting-point metals such as cast iron and non-ferrous metals, one can use sand with low purity (94% to 98% pure).
- Silica sand, which is one of the oldest substances on earth, has been in existence since the earth’s formation. Silicon dioxide (SiO2) is a form of this sand and has been crucial to the evolution of life on earth. Primitive life forms used it to create their skeletons and basic structures, while prehistoric plants employed this substance as support structures.
Characteristics:
1. Physical Properties:
Color and Clarity: Silica sand is typically colorless to white, but can also appear in shades of gray, brown, or pink depending on impurities. The color often indicates the presence of other minerals.
Texture: It has a granular texture and can range from very fine to coarse grains.
Hardness: Silica sand is notably hard, with a hardness of 7 on the Mohs scale, which makes it suitable for abrasive applications.
2. Grain Size Distribution:
Silica sand is classified by its grain size, ranging from fine to coarse. The grain size affects its suitability for different uses; for example, finer grains are used in glass manufacturing, while coarser grains are used in construction.
3. Shape:
The shape of silica sand grains can be angular or rounded. Rounded grains are typically preferred in applications like glass manufacturing and casting due to their better flow characteristics.
Grain Size: Varies from fine to coarse, with different applications requiring different grain sizes.
| S.No | Parameter | Unit | Test Result | Test Method |
|---|---|---|---|---|
| 1 | Fineness Modulus | % | 1.8 | Calculation |
| Sieve Analysis | ||||
| 2 | Retained on Mesh 4 | % | 0 | Gravimetric |
| 3 | Retained on Mesh 8 | % | 0.31 | Gravimetric |
| 4 | Retained on Mesh 16 | % | 4.12 | Gravimetric |
| 5 | Retained on Mesh 30 | % | 19.34 | Gravimetric |
| 6 | Retained on Mesh 50 | % | 39.85 | Gravimetric |
| 7 | Retained on Mesh 100 | % | 24.38 | Gravimetric |
| 8 | Retained on Mesh 200 | % | 9.08 | Gravimetric |
| 9 | Passing by Mesh 200 | % | 2.92 | Gravimetric |
Sieve Analysis - Mesh 10 – Mesh 140
| S.No | Description | Grain Size (mm) | Weight 1 (Grams) | Weight 2 (Grams) | Total Weight (Grams) | Percentage |
|---|---|---|---|---|---|---|
| 1 | Weight with Moisture | 10500 | 10500 | 100.00% | ||
| 2 | Weight with Moisture | 9537 | 486 | 10023 | 95.46% | |
| 3 | Moisture | 477 | 4.54% | |||
| MESH | ||||||
| 4 | #<10 | > 2mm | 2 | 2 | 0.02% | |
| 5 | #10 - > 20 | 2mm - 0.84mm | 30 | 613 | 643 | 6.12% |
| 6 | #20 - < 24 | 0.84mm - 0.71mm | 38 | 828 | 866 | 8.25% |
| 7 | 0.71mm - 0.6mm | 42 | 979 | 1021 | 9.72% | |
| 8 | #30 - < 40 | 0.6mm - 0.425mm | 60 | 1216 | 1276 | 12.15% |
| 9 | #40 - < 60 | 0.425mm - 0.25mm | 127 | 2548 | 2675 | 25.48% |
| 10 | #60 - < 80 | 0.25mm - 0.18mm | 70 | 1608 | 1678 | 15.98% |
| 11 | #80 - < 100 | 0.18mm - 0.15mm | 23 | 242 | 265 | 2.52% |
| 12 | #100 - < 140 | 0.15mm - 0.106mm | 40 | 670 | 710 | 6.76% |
| 13 | # >=140 | < 0.106mm | 52 | 831 | 883 | 8.41% |
| 14 | 10019 | 95.42% | ||||
| 15 | Weight Loss | 4 | 0.04% |
Chemical Composition:
Main Component
Silicon Dioxide (SiO₂):
Percentage: Typically 95-99% of silica sand.
Properties: Silicon dioxide is a stable and chemically inert compound, making it ideal for various industrial uses.
Impurities and Trace Elements
Iron Oxides (Fe₂O₃):
Percentage: Often found in small amounts, varying from 0.1% to 5% depending on the source.
Impact: Iron oxides can give silica sand a reddish or yellowish color and may affect its suitability for applications requiring high purity.
Aluminum Oxides (Al₂O₃):
Percentage: Generally present in trace amounts, less than 1%.
Impact: Contributes to the sand’s hardness and abrasion resistance.
Calcium Carbonate (CaCO₃):
Percentage: Typically less than 1%.
Impact: Can influence the sand’s color and is more commonly found in certain geological formations.
Feldspar:
Percentage: Usually present in small amounts.
Impact: A group of minerals that can affect the sand's properties, such as its melting point and chemical reactivity.
Clay Minerals:
Percentage: Generally found in trace amounts.
Impact: Can affect the sand’s flow properties and its suitability for certain applications.
Other Minerals:
Quartz: As the primary component, quartz itself is a form of silicon dioxide, but it may also include other minerals in minor amounts, such as mica or zircon.
Industrial Uses:
Glass Manufacturing:
Flat Glass: Used in windows and mirrors due to its purity and transparency.
Container Glass: For bottles and jars, requiring a high level of purity and uniformity.
Specialty Glass: Includes fiberglass and advanced glass materials used in electronics and aerospace.
Construction Application:
Concrete Production: Added to cement to improve strength and durability.
Mortar: Used in masonry and tile grout.
Asphalt: Mixed with bitumen to improve the strength and durability of road surfaces.
Foundries Application:
Casting: Silica sand is used as a mold material in metal casting processes due to its high melting point and ability to withstand high temperatures.
Oil and Gas Industry:
Hydraulic Fracturing (Fracking): Silica sand is used as a proppant in hydraulic fracturing to keep fractures open in the rock, allowing oil and gas to flow more freely.
Water Filtration Application:
Filtration Systems: Silica sand is used in water treatment facilities to filter out contaminants and particulates from drinking water and wastewater.
Recreational Application:
Sandboxes and Playgrounds: Provides a safe, clean, and comfortable surface for children’s play.
Sports Fields: Used in fields and tracks for its consistency and drainage properties.
Abrasives Application:
Sandblasting: Silica sand is used as an abrasive material for cleaning and etching surfaces.
