Australia boasts one of the most competitive dust suppression products ‘melting pot’ in the world given its very active unsealed roads network, agricultural activities and the thriving mining sectors. Dust control technologies have always been at the core of suppression of fugitive dust in the different activities which is also an evolving industry with constant changes and comparisons between the old and the new. Resistance to change and embracing more environmentally friendly products can be attributed to the failure to consider the sustainability footprint of product development from formulation to application. A closer look at the recent developments in dust control products shows that Australia has started to embrace more rigorously tested dust suppression products which are non-traditional relative to traditional ones. The reasons for that are based on research and scientific evidence with proven results to cement and place global innovative companies such as Global Road Technology at the forefront of the wave of change and value for the product technologies without compromise on the environment. The article seeks to compare dust suppression products in Australia whilst answering the following questions:

  • What dust suppression products are available in Australia?
  • What are the benefits and drawbacks of the dust suppression products?
  • What are the new generation and evolving technologies in dust suppression products?

Technology Overview

There is a long list of dust suppression products available in Australia hence the descriptions will be short and precise in the interest of just naming them. Although we acknowledge the variety of dust suppression products, the article seeks to build a case for discussing the benefits and drawbacks of using these dust suppression products using comparisons between lignosulfonates and bitumen emulsions. The in-depth analysis of these two dust suppression products will be penultimate to just the list of available dust suppression products in Australia which will be summed up with the products formulated by Global Road Technology. Dust suppression products available in Australia include the readily and normally available water which agglomerates surface particles but tends evaporate easily and requires frequent re-application which depends on humidity and temperature. Salts such as calcium chloride, magnesium chloride and sodium chloride have the ability to absorb water and significantly increase surface tension of water film between particles therefore slowing down evaporation but require minimum humidity levels to absorb moisture from the air.  

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In the organic and non-petroleum category tall oil derivatives adhere to surface particles under dry conditions but are compromised by long term exposure to heavy rain. Molasses provide temporary binding of surface particles but have limited availability whereas vegetable oils agglomerate the surface particles but oxidize rapidly and become brittle. Biofluids agglomerate surface particles but require minimum humidity levels to absorb moisture from the air more or less similar to the limitations of salts. In the organic petroleum, petroleum resin and mineral oil category petroleum resins bind and agglomerate surface particles but have a crust, which is difficult to maintain. Mineral oils and base oils agglomerate surface particles and are applied in their neat form hence do not require any dilution with water but only come as a temporary dust control measure which is also accelerated by lack of field test data. Synthetic polymer emulsions bind surface particles together via their adhesive properties which increases the shear strength of the material but are difficult to maintain as a hard surface and are susceptible to photodegradation. Electrochemical derivatives, sulfonated oils and enzymes change the characteristics of clay size particles which tends to be effective regardless of climatic conditions, but performance is dependent on fine clay mineralogy and need time to react with the clay fraction. Mechanical dust suppression is achieved through use of clay additives such as bentonite which is the most common and it agglomerates with fine dust particles which increases the dry strength of materials under dry conditions however the surface may become slippery when wet if too much is added. 

Lignosulfonate and Bitumen Emulsions

As an introduction, these technologies are often promoted as multi-purpose and environmentally friendly. We make a more in-depth comparison between lignosulfonates relative to bitumen emulsions. Lignosulfonate is a polyelectrolyte polymer that has good water solubility and its aqueous solution consists of a mass of anions. It is a by-product of the chemical pulping industry, during the pulping process the lignin in wood becomes water soluble through sulfonation and upon dissolution of the lignin, the original cell structure is destroyed, and cellulose fibers separate from the sulfite lignin yielding lignosulfonate. Its advantages include cementing soil grains together, formation of a crust which renders a strong structure and is effective in resisting external erosion. It can also be used as a clay dispersant which reduces void volume in soil and increases the structure strength. On the downside, in the presence of rainfall it tends to leach away consequently leading to its significant reduction in concentration within the surface layer or pavement layer. Lignosulfonates are known to be corrosive to some metals and their alloys as well. 

Bitumen emulsions are formulated from water, neat of polymer modified bitumen in the presence of a surfactant to form either a water in oil or oil in water emulsion. The dispersed phase of bitumen is dispersed in the continuous phase of water in the presence of surfactant which reduces the surface tension between bitumen and water. Bitumen emulsion binds and agglomerates surface particles because of bitumen adhesive properties. It also serves to waterproof the surface. The limitations include possible release of polycyclic aromatic hydrocarbons as a result of runoff into waterbodies which could result in genetic defects amongst many other problems associated with bitumen chemistry when exposed to the environment owing to its non-biodegradability. Bitumen emulsion applications can be limited as a result of too many fines relative to high asphaltene content of the bitumen which can lead to crust formation and fragmentation under traffic and in wet weather. The phase chemistry of bitumen emulsion also makes applications difficult to maintain. Along with their surfactants, these technologies are toxic to the environment, particularly as the build up in the soil profile and can bioaccumulate and mobilise.

So what do you guys offer?

Unlike a one-product fits all approach Global Road Technology offers different products for each unique dust control and suppression scenario. GRT Haul-Loc is a specially formulated liquid polymer designed for the mining and resource sectors to bind fine dust particles and reducing the chances of them being airborne as fugitive dust.  GRT Wet-Loc a highly refined synthetic fluid is the latest environmentally friendly dust control product on offer which works through adsorption onto the treated surface, making dust particles heavy to be airborne. GRT Activate UG is used on the coal dust in longwall and continuous miner operations owing to its hydrophobic nature whereas GRT Activate is ionically charged and finds its use in material crushing, transfer and handling operations. The mechanism of action for GRT 5000 utilizes a robust liquid polymer which provides surface coating for the civil and mining sectors. The incentive for using GRT products is that they can work in combination for example GRT Activate and GRT Ore-Loc to achieve a more holistic bulk material dust control using ionically charged technologies and robust, liquid polymer technologies to provide dust control in the resource sectors such as coal and ore mining and port activity stockyards via liquid tarping. 

Solutions

There are many dust suppression products these include water, salts, bitumen emulsions, lignosulfonates, enzymes, mineral oils, tall oils amongst many other varieties. Each dust suppression product has benefits and drawbacks in some instances some product benefits overlap whilst some are unique but overall the new generation of dust suppressants provides more targeted dust control with incentive for being robust and environmentally friendly. Liquid polymers, eco-friendly surfactants, and highly refined synthetic fluids are amongst the recent and tailor-made solutions offered by Global Road Technology.

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REFERENCES 

  • Ball, G.F.A., Herrington, P.R., Patrick, J.E. 2008. Environmental Effects of Emulsions. Land Transport New Zealand Research Report 343. 
  • Ding, X., Xu, G., Kizil, M., Zhou, W., and Guo, X. 2018. Lignosulfonate Treating Bauxite Dust Pollution: Effect of Mechanical Properties and Wind Erosion Behavior. Water Air Soil Pollut. 229:214. 1-13.
  • Hossain, S.Z., Mumford, K.G., and Rutter, A. 2017. Laboratory study of mass transfer from diluted bitumen trapped in gravel. Environmental Science: Processes & Impacts. 
  • Hua, Y., Mirnaghi, F.S., Yang, Z., Hollebone, B.P., and Brown, C.E. 2017. Effect of evaporative weathering and oil-sediment interactions on the fate and behavior of diluted bitumen in marine environments. Part 1. Spill-related properties, oil buoyancy, and oil-particulate aggregates characterization. Chemosphere. 191. 10381047.