Illinois Mining Institute Annual Meeting August 25, 2015 Types of Dust Suppressants and How They Function Tony Malloy © 2013 Quaker Chemical Corporation. All rights reserved.

A SINGLE DUST SUPPRESSANT CAN NOT CONTROL EVERY DUST PROBLEM OVERVIEW A SINGLE DUST SUPPRESSANT CAN NOT CONTROL EVERY DUST PROBLEM © 2013 Quaker Chemical Corporation. All rights reserved.

Dust Suppressant Categories Controls Dust where it ORIGINATES Controls Dust where it ACCUMULATES © 2013 Quaker Chemical Corporation. All rights reserved.

Type of Product that Controls Dust where it Originates Surfactants in Water This type can be used at: Crushers Conveyor Transfer Points Continuous Miners Shearer Longwall Shearer

How Surfactants in Water Function Lowers Surface Tension of water which allows water to adsorb onto dust surface and absorb into dust particles. With the correct nozzles, water will form small droplets to improve opportunity of hitting fine dust. © 2013 Quaker Chemical Corporation. All rights reserved.

Products That Control Dust where it Accumulates Water Moisture Absorbing (Hygroscopic) compounds Petroleum type Organic Non-Petroleum type Electrochemical Synthetic Polymer Clay Additives

Water Controls Some Dust where it Accumulates Water without additives can be used on some materials to control dust Water without additives does not control coal dust Lasts only 2 – 8 hours, or until it evaporates, depending on temperature Higher cost than expected Time Equipment

How Water alone Functions It is absorbed by most particles and makes material bind together. As material increase in weight, its ability to become airborne decrease. As water evaporates, material weight decreases, clumped pieces break apart, and eventually the fine size particles become airborne again. © 2013 Quaker Chemical Corporation. All rights reserved.

Moisture Absorbing Compounds Control Dust where it Accumulates Salts / Brines Calcium chloride, Magnesium chloride, Sodium chloride Other Hygroscopic materials Glycerine Ethanol Methanol Diesel fuel Sugar

How Salts / Brines Function Absorb air moisture depending on relative humidity. Calcium chloride begins absorbing at 20% - 29% Magnesium chloride begins absorbing near 32% Sodium chloride begins absorbing near 79% Moisture Binds particles together to increase total weight / prevents them from becoming airborne. Best time to use during morning hours when relative humidity is typically high and temperatures are low. © 2013 Quaker Chemical Corporation. All rights reserved.

Petroleum Products Control Dust where it Accumulates Asphalt emulsions Asphalt – pitch after distillation of petroleum Cationic or Anionic emulsifiers Water Cutback asphalt Petroleum solvents

How Petroleum base product Function Mix of product and water is applied which migrate into the material containing the dust. The strong adhesive properties easily binds all particles together forming a continuous layer of surface material and petroleum. After the water in the emulsion evaporates, the film becomes water resistant. © 2013 Quaker Chemical Corporation. All rights reserved.

Non-Petroleum Organic products control dust where it Accumulates Lignin Extracted from softwood tree cells By the sulfite paper making process Tall-oil Derivatives From the sulfate (Kraft) paper making process Vegetable oils Soybean soapstock

How Non-Petroleum products Function Mix of product and water is applied which migrates into the material containing the dust. Surfactants in the application emulsion also help product penetrate into the gravel surface. Have slightly less adhesive properties than petroleum product, but also binds surface particles together forming a continuous film. After the water in the emulsion evaporates, the film becomes water resistant. © 2013 Quaker Chemical Corporation. All rights reserved.

Electrochemical Product control Dust where it Accumulates Enzymes Act as a catalyst to help fine clay size particles bind with road aggregate Not effective on all road surfaces Ionic materials Cationic type product has positive charged droplets Anionic type product has negative charged droplets

How Electrochemical products function Enzymes: Do not become part of the final surface, but act as an aid in the process of particles binding together. Used with very fine dust that have an electrical charge. Must be mixed into the roadbed using road grader or rake. Effective regardless of weather conditions. Ionic materials: Cationic products function using electric field attraction by attaching to negative charged surfaces. Anionic products function using electric field attraction by attaching to positive charged surfaces. © 2013 Quaker Chemical Corporation. All rights reserved.

Synthetic Polymers control Dust where it Accumulates Synthetic polymers, such as polyvinyl acrylics and acetates, are the primary film forming ingredient These polymers are manufactured from readily available starting materials

How Polymer Suppressant Functions Mix of product and water is applied which migrates into the material containing dust particles. Gradual evaporation of water and coalescing agent until the polymers soften and connect. The polymer continue to coalescence and generate a continuous film. After all water and coalescing agent has evaporated, the film will be water resistant. © 2013 Quaker Chemical Corporation. All rights reserved.

Evaporation Process

Clay Type Suppressants control Dust where it Accumulates Bentonite is a clay processed from volcanic ash Very fine material, 2 microns or less Has strong colloidal properties Volume increases several times in contact with water

How Bentonite Suppressant Functions Bentonite is mixed with water and applied as a slurry. The bentonite slurry must be mechanically mixed with road material using road grader or rake. The mix water increases the volume of the bentonite particles and also make them tacky. The tacky bentonite binds the fine dust with larger size material and prevents airborne dust. © 2013 Quaker Chemical Corporation. All rights reserved.

Conclusions Two Categories of Dust Suppressants Where dust originates Where dust accumulates Various products to use where dust accumulates Brines, Petroleum, Non-Petroleum, Electrochemical, Synthetic Polymers, and Clay Additives Variables affecting Suppressant Performance: Wind, moisture, local temperature Geological material creating the dust Traffic conditions Industrial activity

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