Safer Frother Option for Coal Flotation – A Review Akira Otsuki 1* , Tamara Miller 2 1 Ecole Nationale Supérieure de Géologie, GeoRessources UMR 7359 CNRS, University of Lorraine, 2 Rue du Doyen Marcel Roubault, BP 10162, 54505 Vandoeuvre-lès-Nancy, France. 2 WA School of Mines, Curtin University, Kalgoorlie, Australia Email: akira.otsuki@univ-lorraine.fr Abstract. A safer frother option for coal flotation in comparison with the common frother methyl isobutyl carbinol (MIBC) was searched and compared through literature review. Results of literature review and comparison of different frothers in safety and environmental aspects show that pine oil and DowFroth have a strong potential to replace MIBC since it has high flash point (78 °C, 149 °C, respectively), and dual frothing and collecting properties to be used as a stand-alone reagent for coal flotation. It can significantly reduce the risk of potential hazard associated with MIBC and oil collector. Keywords: Occupational health and safety, flash point, exposure, environment, methyl isobutyl carbinol. 1 Introduction Occupational health and safety (OHS) is set to create a safe working environment to employees. In Australia, for example, each state government places a different set of mining regulations. These regulations are continuously getting stricter on items allowed in mine sites. Many metallurgical processes require the use of hazardous chemicals which could create hazards while in transport, use and disposal. Since the regulations are getting stricter, some of those chemicals may not be allowed to be used in mine sites in the future. This creates the need to find safer alternative chemicals or processes to keep employees safe. Coal processing is one of such processes that use hazardous reagents. Methyl isobutyl carbinol (MIBC, C 6 H 14 O) is a common frother but also collector used in coal flotation and has a low flash point (F.P. = 39 °C; [1]). This can cause incidents such as what happened in a Queensland coal preparation plant in 2003. The power to some MIBC pumps was tripped, once they were reset, powered up a flash and then a fire was observed behind the pumps. This is due to the flash point of MIBC being 39 °C and as the vapour is heavier than air, an explosive mix will form under the right conditions [2]. There have also been incidents involving MIBC transport trucks. These dangers highlight the need to find a safer frother reagent. Thus, frother manufacturers are trying to develop/find alternatives. Coal has been used as an energy source for hundreds of years, and becoming more important in recent years. In 2011, it generated 42% of the world’s electricity and was recorded as one of the fastest growing energy sources [3]. There are two major coal categories. Thermal coal is used mainly for power generation while metallurgical coal is used in raw iron manufacturing. Thermal coal has a relatively low value, meaning that less cost intensive processes have to apply for its recovery. Metallurgical coal used in the manufacture of metallurgical coke is, on the other hand, worth more; so companies can use more cost extensive process methods for its recovery. Coal can be mined from either surface or underground. In Australia, as an example, the major source is surface-mining, which affects the coal processing and also its use as an energy source. The closer to the surface the coal recovered from, the more weathered and oxidized it becomes. The oxidized coal exhibits different properties from the underground coal with its unoxidized surface. Such oxidation can make coal difficult to process by flotation because oxidized coal surface is less hydrophobic. Therefore, the intense coal oxidation requires modifications of extraction methodology. Once the coal is mined, it can be classified into four size categories: coarse particles (+10 mm), intermediate (10 mm – 1 mm), fine (1 mm – 150 µm) and ultrafine (-150 µm) particles [4]. To separate Current Works in Mineral Processing, Vol. 1, No. 1, March, 2019 https://dx.doi.org/10.22606/cwimp.2019.11003 21 Copyright © 2019 Isaac Scientific Publishing CWiMP