Industrial sand, also known as silica sand, is a common material used in a wide range of industrial applications due to its unique physical and chemical properties. Unlike your regular construction sand, industrial sand is manufactured with precise specifications that make it valuable for specific uses like glassmaking, foundry casting, hydraulic fracturing, filtration, and more.
But what makes industrial sand so valuable? This article will explore the important properties of it in depth and help you understand why they are essential for industrial applications.
Composition and Purity
First, let’s take a look at the composition of industrial sand and why those specific compositions are needed for industrial applications:
High Silica Content
The most defining characteristic of industrial sand is that it is high in silica, which is just silicon dioxide (SiO?). This is why it is also called silica sand. It is primarily composed of quartz, which is a hard and chemically inert mineral with a high melting point. Most industry-grade silica sands contain more than 95% silicon dioxide, with some applications requiring even higher purity levels.
The purpose of the high silica content is to ensure that the sand behaves predictably when exposed to high temperatures or chemical processes. As an example, we can take a look at glass manufacturing, where the presence of impurities like iron can discolor the final product. This makes ultra-pure silica essential for producing clear transparent glass.
Absence of Contaminants
To qualify as industrial sand, the material must have minimal levels of contaminants. Clay, feldspar, iron oxides, and organic matters are all impurities that can significantly alter the chemical behavior of the sand, especially in sensitive processes like semiconductor fabrication or precision casting.
But impurities in industrial procedures can lead to severe issues. So these impurities are typically removed from the sand through washing, magnetic separation, or other processes. In glassmaking, the low presence of iron among other things is crucial to avoid greenish-brown tints in the final product.
Grain Size and Shape
The size and shape of the grains of sand also contributes to making it suitable to be industrial grade. Here, two factors come into play:
Size Distribution of Grains
Grain size has an affect on permeability, compaction, surface area, and interaction with other materials. Depending on the application, the grain size of industrial sand must fall within a small range.
For example, in hydraulic fracturing, sand must be fine enough to travel through tiny fractures but also coarse enough to prop those fractures open once the pressure is released.
Angular vs. Rounded Grains
The shape of sand grains determines how they interact with other materials. Rounded grains are preferred in applications where flow is important, such as in fluidized beds. In ths case, the smooth edges reduce friction and allow better packing efficiency.
On the other hand, angular grains provide better interlocking properties. This makes them ideal for foundry molds where stability and strength are of higher importance.
Mechanical Strength
In many industrial applications, sand is subjected to a lot mechanical stress. There are important differences between the mechanical strength of regular sand and industrial sand. They are:
Crush Resistance
The crush resistance of industrial sand is tested under standardized conditions, and only sands meeting certain thresholds are considered suitable for industrial environments. High crush strength ensures that the sand maintains porosity and enables oil and gas to flow freely.
For example, in the oil and gas industry, silica sand is used as a proppant in hydraulic fracturing. This is because in this procedure, the sand must withstand high closure pressures without breaking down into smaller particles.
Durability and Hardness
Quartz, the main component of silica sand, is ranked 7th on the Mohs scale of mineral hardness, which makes it one of the most durable natural materials. This hardness resists abrasion and degradation during processing and application. Durability is particularly important in foundry, where sand must be reused again and again.
Thermal and Chemical Stability
Industrial sand’s thermal and chemical properties also make it advantageous for such applications. The properties are:
High Melting Point
Industrial sand has a high melting point of around 1,650°C (3,002°F). This makes it suitable for applications involving high levels of heat, such as manufacturing ceramics, glass, and refractory bricks.
This thermal stability also lets silica sand maintain its structural integrity in foundry molds and cores, which reduces the risk of deformation or collapse during metal pouring.
Low Thermal Expansion
Low thermal expansion is another valuable property of industrial sand’s primary component, quartz. The risk of cracking or warping in precision molds and products exposed to temperature fluctuations is minimized thanks to this properly. It further contributes to dimensional stability necessary in producing high-tolerance components in casting and glassmaking.
Resistance to Chemical Reactions
Industrial sand is chemically inert, which makes it a reliable medium in environments with rigorous chemical activity. The material does not readily react with acids except hydrofluoric acid, as well as alkalis or oxidizing agents.
Filtration Capabilities
The composition and chemical inertness of industrial sand makes it suitable for filtration purposes. This is explained below:
Ideal Porosity and Permeability
In water and wastewater treatment, industrial sand is used as a filtration medium. The uniform grain size and optimal porosity of this material allows water to pass through while trapping particulates within it.
For the same reason, a well-sorted bed of industrial sand ensures consistent flow rates and efficient removal of suspended solids, bacteria, and other contaminants. If the grain is angular, it can improve particle retention, which will enhance the performance of multimedia filters and slow sand filters.
Longevity
Filtration-grade industrial sand can be cleaned and reused multiple times. This makes it a cost-effective and environmentally friendly choice. Its durability and resistance to breakdown are the two main factors that contribute to its long service life, reducing the need for frequent replacement.
Industrial sand is a lot more than a basic raw material. It is a highly specialized product whose valuable combination of physical, chemical, thermal, and mechanical properties makes it ideal for industrial purposes. Understanding these properties allows manufacturers and engineers to select the right type of sand for their specific needs, all while maintaining performance standards and regulatory compliance.
