Purification of Sulfur Waste Under Hydrothermal Conditions

Abstract

Abstract: Large scale of sulfuric acid production leads to huge amount of solid state industrial waste, which is stored in landfill sites and may cause many environmental problems. The purpose of this study is to characterize the sulfur waste and to determine the optimal conditions of sulfur regeneration from waste under hydrothermal conditions.Therefore the recovery of elemental sulfur from waste (waste product of sulfuric acid production) was investigated. Samples were examined by simultaneous thermal analysis (STA), X-ray diffraction analysis (XRD) and X-ray fluorescence spectroscopy (XRF). It was determined that the used material mainly consisted of sulfur (86.3%), calcium (6.9%), iron (4%) and silicon (2.3%). The primary methods and conditions of waste preparation for further treatment were determined. It was established that sulfur and impurities (e.g. quartz, calcium compounds) can be separated by applying rapid cooling procedure after hydrothermal treatment. Most efficient conditions of sulfur waste purification were determined and the maximum obtained yield of purification was 97.35%. Graphic abstract: [Figure not available: see fulltext.]