Selecting Efficient Surfactants for Dust Suppression during the Production of Crushed Stone

The dust content in the working area during the production of crushed stone remains a key problem for the prevention of occupational illnesses to which 2 % to 12 % of employees are exposed, even when a plant is equipped with modern dust suppression units. The issue of increasing the efficiency of dust suppression with wetting agents has not been addressed yet and requires a comprehensive study of properties and the search for additional factors determining their efficiency. The study aims to select efficient surfactants as wetting agents to suppress dust at a crusher plant. To determine the key factor characterizing the efficiency of dust suppression with wetting agents, comprehensive studies of properties of efficient surfactants have been conducted, including measuring the surface tension at the «solution–air» boundary, the wetting ability, the time of wetting, dust dispersibility, and sprayed solutions. As studies have shown, the surface tension of water solutions plays the key role in the determination of wetting ability, increasing from 70 % to 95 % when the surface tension is reduced from 72.86 mN/m to 26.07 mN/m. Measuring the time of submersion of dust particles into a water solution has detected an exponential dependence on the surface tension; however, the wetting time is reduced by 167–720 times when the surface tension is reduced. The surface tension impacts the interaction between dust particles and the solution of surfactants and the formation of drops during the dispersion, whose dispersibility increases by more than twice. Based on the comprehensive analysis at the crusher plant, wetting agents based on sodium sulfate (C8–C10) or zinc cocosulfate have been recommended for use. The approximation of the obtained data helps to forecast the basic characteristics of wetting agents outlining the efficiency of dust suppression of silica dust. The study results can be used when selecting an efficient wetting agent for dust suppression during production, as well as for manufacturers involved in the development of wetting agent compositions.