Assessment of the water quality produced from mechanical thermal expression processing of three Latrobe Valley lignites

Physicochemical properties of wastewater produced from the microwave upgrading process of Indonesian lignite

“…When microwave time was increased from 2 min to 12 min, the pH of removed water gradually decreased from 4.26 to 3.98. This result well agreed with that of wastewater produced by mechanical thermal expression of lignite within a pH range of 3-5 [59,60]. The presence of significant moisture and polar functional groups in lignite resulted in a negative potential of lignite particle surfaces and acidity of moisture in lignite.…”

“…This process was typical ion exchange wherein the displacement of protons into removed water resulted in decreased pH. With prolonged microwave time, the decrease in pH of removed water can be attributed to the progressive release of organic acid matter during lignite dewatering [59].…”

The Fate of Trace Elements During MTE and HTD Dewatering of Latrobe Valley Brown Coals

“…Due to the higher temperatures of HTD and the associated degradation of carboxylic acid functional groups, MTE water is generally expected to contain less inorganic and organic contamination. Whilst several examples have shown significant differences in the composition of both MTE and HTD waters produced from similar coals [6][7][8], there has been only one direct comparison for the same substrate coal [9]. Moreover, to date there have been limited comparative data concerning the composition and concentration of common inorganic components (Na, Ca, Mg, K, Al, and Fe) in the product waters produced by these different approaches.…”

An environment friendly and efficient lignite-fired power generation process based on a boiler with an open pulverizing system and the recovery of water from mill-exhaust

“…However, this approach is limited by the high temperature and high-pressure conditions associated with dewatering, with the result being that dewatering equipment is difficult to upsize to full production scales. Additionally, the wastewater discharged from dewatering systems is unsuitable for most reuse scenarios due to its acidic, salty and carbon rich nature, as indicated by Butler et al [9]. Clearly, the various lignite drying technologies each have their own difficulties, and before any of these technologies can be applied to large-scale engineering operations, they must be further researched and improved.…”