Methods of arsenic wastes recycling: Focus on flotation

Arsenic in water poses today a serious threat to the health of people in many countries. Also, oxidative weathering and dissolution of As-containing minerals (such as arsenopyrite and other gangue minerals), among other, of dissolved inorganic arsenic oxyanions that are transported in surface or groundwater, can subsequently become adsorbed on soil and sediment particles. The removal of arsenic, i.e. from mine tailings, could meanwhile render them suitable for recycling and hence, sustainability. For centuries, water has been a manufacturing tool that industry has taken for granted, because it was inexpensive and plentiful. Flotation, being a unique separation technique, initially originated from mineral beneficiation. In line with flotation, specific investigations are usually required: such as measurements of the particles' electrokinetic behavior, contact angle with the gas bubbles, aqueous speciation of the studied system and in general, chemistry; as the presence of the appropriate surfactants, frothers, depressants and modifiers help the efficient separation process. Another focus of the present work constitutes the economic aspect may be of the recovery of useful valuable minerals (i.e., gold), contributing to recycling meanwhile with environmental technology and wastewater treatment. For instance, arsenic-rich auriferous pyrite concentrates, often stockpiled in the mine area, could be further enriched in arsenic to assist also Au beneficiation, in case gold is associated with arsenopyrite (as it is the case studied in the present). Such arsenic removal is accomplished by sorption, including biosorption, flotation etc. and perhaps, a combined process with membranes separation downstream, too.