Evidence from lab and field points to surfactants and hygroscopic salts dramatically improving dust control while slashing water use and spray frequency, with net cost savings versus plain water.
In the dusty world of quarry haul roads and crushers, water trucks are the blunt instrument. The problem: plain water evaporates fast and runs off, delivering only short-lived control. Studies and field trials now show that “chemistry in the water”—low-dose surfactants (surface-active agents that reduce water’s surface tension) and hygroscopic salts such as magnesium chloride (salts that actively absorb moisture from air)—can change the equation.
In controlled testing, surfactant-treated sprays captured 80–95% of total dust—roughly 40 percentage points higher than plain water—at extremely low concentrations like 0.01–0.1% (www.sciencedirect.com) (link.springer.com). One study reported ~90% reduction of respirable dust (fine particles capable of reaching the lungs) using just 0.025% of a nonionic surfactant, far outperforming water alone (www.sciencedirect.com) (link.springer.com).
Hygroscopic salts take a different tack: they hold onto moisture and leave a residual brine that binds fines for weeks. Field reports cite magnesium chloride (MgCl₂) keeping roads damp and controlled for 30–90 days per application (www.xrdchemical.com) (dnr.mo.gov), compared with hours or a few days for water alone.
Surfactant-enhanced sprays: wetting and capture
By lowering surface tension, surfactants help spray water spread over hydrophobic dust, penetrate particles, and form aggregates that are more readily bound by moisture (www.sciencedirect.com) (link.springer.com). The result: 80–95% capture of total dust, about 40 percentage points higher than plain water, at 0.01–0.1% dose levels (www.sciencedirect.com) (link.springer.com).
With higher per-spray efficiency, plants can use markedly less water over time. There’s a longevity effect too: a Triton X‑100 surfactant solution took 610 minutes to stabilize (i.e., largely evaporate) under test conditions versus 540 minutes for plain water (www.mdpi.com). Plain water on hot, dry surfaces commonly dries in hours, pushing multiple applications per day (link.springer.com). Specialists note that surfactant sprays allow fewer applications (beta.co.id) (beta.co.id). Quantitatively, if surfactants boost efficiency by ~40%, operators can achieve the same dust control with roughly 40% less water over time (www.sciencedirect.com) (beta.co.id).
Additives are mixed into the water used in spray systems, where accurate chemical dosing helps maintain these low concentrations; in plant practice, that points to equipment such as an accurate chemical dosing pump to keep mix ratios consistent.
Hygroscopic salt additives: moisture retention and road binding
Magnesium chloride and calcium chloride (CaCl₂) absorb atmospheric moisture and form a residual brine that binds particles, resists evaporation, and extends suppression duration to weeks (www.xrdchemical.com) (dnr.mo.gov). Typical MgCl₂ brine rates are ~0.25–0.5 gal/yd² (≈1–2 L/m²), with CaCl₂ used similarly at ~0.2–1 gal/yd² (dnr.mo.gov). Reapplication is far less frequent: “once or twice a season” depending on traffic and rain (dnr.mo.gov).
In a Colorado road trial, untreated sections needed eight sprayings per year; MgCl₂- or CaCl₂-treated roads needed about two—cutting events by 75% (www.gxcontractor.com). In arid quarry environments (similar to conditions in parts of Indonesia), salts can slash total water use by keeping surfaces moist from ambient humidity. MgCl₂ is widely used because it is less corrosive and works in lower humidity than CaCl₂ (www.xrdchemical.com) (dnr.mo.gov), and it binds fines, helping seal surfaces, reduce gravel loss, and limit erosion (dnr.mo.gov) (dnr.mo.gov). Field observers report 50–70% less airborne dust with salinated roads vs. untreated (www.gxcontractor.com).
Trade-offs matter: elevated chlorides can harm vegetation and corrode equipment (www.researchgate.net) (dnr.mo.gov), although a performance comparison notes magnesium chloride is generally considered less environmentally damaging than CaCl₂ (www.xrdchemical.com). For quarry haul roads, vendors also market targeted products such as a hauling road dust suppressant to deliver these moisture-retaining effects.
Water savings and frequency reduction
Surfactants and hygroscopic salts both reduce water demand and spray frequency—surfactants by improving capture per liter, salts by extending how long a surface stays damp. Used together, they can multiply savings: a surfactant might enable ~40% fewer repeat sprays, and MgCl₂ might shift routines from daily to monthly watering. Water-only control often demands daily or continuous use.
Example: a haul road watered five days a week with plain water (~250 sprays/year). Adding a surfactant can cut that to ~2–3 days per week; using MgCl₂ brine can drop it to once every few weeks. In the Colorado trial, switching from water-only to MgCl₂/CaCl₂ saved 75% of spray events (www.gxcontractor.com). If each spray uses 10 m³ of water, that’s ~40 m³ saved weekly. Manufacturers emphasize that MgCl₂ “remains effective for weeks” and “reduces maintenance costs” by minimizing truck water loads (www.nationwidelandworks.com) (www.gxcontractor.com). Specialists also note chemical suppressants “require less water” than plain sprays (beta.co.id) (www.gxcontractor.com).
Cost–benefit considerations
Materials cost more than water, but field economics often flip in their favor. A lab analysis put annualized per-area costs at 86 yuan for plain water, 312 yuan for CaCl₂ solution, 585 yuan for a surfactant solution, and ~2,184 yuan for polyacrylamide—so chemicals can be 3–7× more per application (www.mdpi.com). Yet in Colorado, chloride treatments roughly halved total annual cost per mile: untreated roads cost ~$20,378/mi·yr; MgCl₂- or CaCl₂-treated roads cost $9,208–$11,107/mi·yr—a 30–46% net saving due to lower watering and grading frequency (www.gxcontractor.com).
Operational math underscores the point. If daily watering (truck plus driver) runs $200/day, shifting to biweekly chemical spray at $300 can save $200 × (5–2) = $600 per week. Case reports note payback from water savings alone, and equipment lasts longer with less abrasive dust (www.gxcontractor.com) (www.mdpi.com).
A full example for a cement quarry: 100 m³/day of spray water equals ~36,500 m³/year. At $0.5/m³, that’s $18,250/year. A surfactant that reduces use by ~40% saves ~$7,300 annually, with chemical cost on the order of $500–1,000/year. A chloride palliative that cuts watering from 250 to 60 events per year saves ~70% of water (~25,500 m³, ~$12,750) for roughly $1,000 in chemicals. Multiple sources confirm that reduced water and labor often outweigh additive expense (www.gxcontractor.com) (www.mdpi.com).
Regulatory and practical context
Indonesian occupational safety (K3) and mining rules require dust control—without dictating the method—while water scarcity and permitting pressures make water-saving approaches attractive. By cutting spray frequency and volume, additive programs reduce utility costs and runoff impact. Firms report reducing watering from daily to weekly or monthly with such treatments; one consultant notes a chloride palliative “minimizes the need for frequent watering” and keeps roads damp during dry spells (www.nationwidelandworks.com) (beta.co.id). By slowing evaporation and improving capture, additives deliver measurable water savings—often tens of percent or more versus pure-water control.
Implementation details matter. Surfactants are used at very low dose, are generally non-toxic, and improve wetting, but some can accelerate corrosion (as noted with Triton X‑100; see www.mdpi.com). Chloride salts must be kept away from drains and monitored for runoff—standard good practice reflected in technical bulletins (www.sciencedirect.com) (www.mdpi.com). In short, data show that specialty additives yield far greater dust control per liter of water and enable far fewer spray events.
Sources: Scientific studies and industry reports on dust control efficiency and costs (www.sciencedirect.com) (www.mdpi.com) (link.springer.com) (dnr.mo.gov) (www.gxcontractor.com) (www.xrdchemical.com) (beta.co.id), including international case analyses and Indonesian-focused technical guidance. All citations give data on dust reduction percentages, water retention times, and economic outcomes for water vs. chemical treatments.
