Bulk material handling of aggregates such as limestone, gravel, and sand remains highly competitive, even in periods of fluctuating economic activity. Product still needs to be moved and transported, deadlines have to be met, and operations must remain profitable.
Top operational goals are ensuring that production continues, material is not wasted, and downtime is minimized. Just as important, operators want to maintain a workplace that is safe for personnel and friendly to neighbors.
Fugitive dust created during aggregate bulk material handling poses a direct challenge to each of these goals. Beyond hindering progress and safety, too much dust can further result in regulatory violations and fines, as well as cause premature failure to rotating equipment and related bearings.
What Is Dust and Where Does It Come From in the Aggregate Plant?
Dust is finely powdered matter generally categorized as 500 microns (µm) or smaller. It can comprise any fine materials present in the material stream. An inherent component of bulk material handling, it can originate throughout an aggregate facility from processes including crushers, haul roads, truck and rail loading and dumping, conveyor transfer points, conveyor belt spillage, and windblown material from stockpiles.
Aggregates produce different types and sizes of airborne dust particles. Larger particles (10 µm or bigger) are heavier and will usually settle on their own. Smaller particles (10 µm or less) can remain suspended in air indefinitely.
What Are the Dangers of Dust?
Large dust particles can be inhaled and then trapped in the nose, throat, or upper respiratory tract. Smaller particles can evade the body’s built-in cleaning mechanisms such as cilia and mucous membranes. They can then travel deeper into the lungs as respirable dust, where they can gather, stay, and form into a significant health problem.
A major concern in producing aggregates such as sand, stone, and gravel is the respiration of crystalline silica dust generated by operations including crushing and screening, conveyor movement, transportation, transfer points, stockpiles, and storage. If enough respirable silica dust is aspirated, it can develop into silicosis, a disabling and irreversible lung disease that can even become fatal.
In addition to posing health risks, fugitive aggregate dust can drift farther into the facility, where it can:
- reduce visibility
- create costly extra housekeeping and maintenance
- cause premature wear on equipment such as pulleys, idlers, motors, and portable conveyors
If left without control methods for too long, the airborne dust also can move into the wider community and endanger it as well.
Fugitive dusting can be greatly reduced and controlled with a properly designed and applied dust suppression system.
Dust Control Limitations in the Aggregates Industry
Dust-reduction methods have included using sprinklers or hoses to weight dust particles with water before they can linger and travel. Over time, however, this practice has often proven to create new issues while only temporarily addressing a dust problem. Aside from requiring extra labor hours, it can result in excess surface saturation and runoff as well.
Properties of water droplets can counteract operators’ dust control efforts as well. Droplets from hoses, sprinklers, and faucets are typically too large, hard, and heavy to properly subdue aggregate dust.
Heavy water droplets remain in the air only shortly, limiting the amount of dust particles they can capture. Water’s high surface tension likewise restricts their capacity in trapping fugitive dust.
When in motion, water’s large droplets create a slipstream air current that dust particles can ride around them. The droplets and particles then cannot make contact, allowing dust to escape.
Standard droplets’ limitations compound even more when a facility operates in arid conditions where water can evaporate more quickly.
Because of their properties, water droplets alone will rarely achieve consistent dust control and prevention.
Dust Suppression for Aggregates
Properly controlling fugitive dust requires water droplets with a size and surface tension that better matches the material being treated. Dust suppression is the engaging of dust particles with traits more certain to subdue them. It achieves this with an eco-friendly, biodegradable dust suppressant with inherent benefits that also help to lower water consumption.
The dust suppression agent breaks the surface tension of the water and particle, thus clinging to the dust particles, increasing their size and weight, and forcing them to fall from the air. When combined with water, the dust suppressant also forms a microscopic film that strengthens the bond between the material surface and dust particles to further restrict their escape. Dust suppression chemicals can help prevent ground-level dust from becoming airborne as well.
A focused and strategic dust suppression system can have a major impact on dust control throughout processes at an aggregate facility, including:
- transloading hoppers
- transfer points
- haul roads
- rail & truck dumps
Portable Power-Free Dust Suppression
Aggregate facilities that contend with dust control in multiple areas may find they require greater ease and versatility in how and where they can apply a solution.
In such instances, dust suppression methods can include a portable powerless system for use at fixed locations. Made for single-person manual operation, the system is a power-free, self-contained enclosure that allows personnel to apply dust suppression chemicals specifically engineered to be non-toxic, non-explosive, and biodegradable anywhere from haul roads to the load zone.
The system becomes a flexible asset in providing dust control with less equipment at fewer application points. It also solves potential problems that involve space and electrical power constraints. At some aggregate facilities, larger, fixed systems may not be feasible because of these constraints.
Benetech: Your Ally in Bulk Material Handling
Benetech understands how crucial dust control is to your success. We engineer, fabricate, and install suppression solutions from powerless to automated plant-wide systems for focusing on your specific challenges. To discover more about how we can make your plant safer, cleaner, and more productive, including with a portable powerless system, contact us at (630) 844-1300 or firstname.lastname@example.org to connect with a specialist.
Posted in Dust Control