Search results for " ash"
showing 10 items of 131 documents
Aeolian Remobilisation of the 2011-Cordón Caulle Tephra-Fallout Deposit: Example of an Important Process in the Life Cycle of Volcanic Ash
2020
The determination of trace element concentrations in fly ash samples using ultrasound-assisted digestion followed with inductively coupled plasma opt…
2009
A method of ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) used for the determination of trace element (chromium, copper, lead, nickel, vanadium and zinc) concentrations in fly ash samples was developed. All the measurements were performed in robust plasma conditions. Ultrasound-assisted digestion procedures using digestion solutions of aqua regia and hydrofluoric acid (HF) resulted in recovery rates of over 80% for all the analyte elements. Ultrasound-assisted two-step digestion with digestion solutions of 6 mL of HNO₃(Step 1) and 3 mL of HNO₃+ 3 mL of HF (Step 2) resulted in recovery rates of over 92% for all the analyte elemen…
Removal of silicon from CFB-derived fly ash leachate in the context of phosphorus recovery
2018
High concentrations of dissolved silica in the acid leachate impose two major challenges on precipitation based recovery of phosphorus (P). Firstly, co-precipitation of colloidal silica in the acidic regimes decreases the purity and value of precipitated P-products. In addition, silica scaling on internal surfaces of equipment is also a problematic issue in industrial operations. Therefore, removal of dissolved silica prior to P-recovery process minimizes the risks of Si-contamination in P-products and Si-scaling. In the present study, silica removal was achieved by accelerated silica polymerization with higher acidity and ionic strength of mineral acid, which also assisted the leaching of …
Pyły przemysłowe jako źródło ferrimagnetyków na terenach wiejskich województwa opolskiego
2010
The use of industrial waste materials for the simultaneous removal of ammonium nitrogen and phosphate from the anaerobic digestion reject water
2020
The European Union’s circular economy strategy aims to increase the recycling and re-use of products and waste materials. According to the strategy, the use of industry waste materials and side flows is required to be more effective. In this research, a chemical precipitation method to simultaneously remove ammonium and phosphate from the reject water of anaerobic digestion plant using calcined paper mill sludge and fly ash as a precipitant, was tested. Paper mill sludge is a waste material formed in the paper-making process, and fly ash is another waste material formed in the power plant. Objective of this research was to test whether these industrial waste streams could be used as low cos…
Method development for determination and recovery of rare earth elements from industrial fly ash
2014
Rare earth elements (REE) are important in numerous high technology applications and in addition their supply risk is high, which gives rise to studying new sources for rare earth elements. Rare earth element concentrations in industrial fly ash samples collected from Finnish power plants, using a mixture of peat and biomass as a fuel, have been determined. Two sample pre-treatment methods, ultrasound- and microwave-assisted acid digestions, have been applied to fly ash samples. Measurement conditions for inductively coupled plasma-optical emission spectrometry (ICP–OES) have been optimized to reach robust plasma conditions and the reliability of the analysis has been investigated by using …
Comparative analysis of the evaluation of the influence of waste on the environment depending on the applied research method (on the example of brown…
2019
The problem of the migration of metal ions in the environment remains a current problem in light of the quality of obtained crops. The necessity of more and more frequent use of alternative sources of biogens in the form of waste substances, poses a threat of loading significant amounts of metals into the soil – including heavy metals harmful to human health and life. The article discusses a significant problem, namely the comparison of the results of the environmental impact of waste, obtained on the basis of legally authorized leaching tests (three-stage leaching test according to PN-EN 12457:2006), with results obtained from sequential chemical extraction (performed in 4-step chemical ex…
Towards controlling PCDD/F production in a multi-fuel fired BFB boiler using two sulfur addition strategies
2014
Abstract PCDD/F abatement strategies – sulfur pellet addition and peat co-combustion – were tested for a BFB boiler facility utilizing SRF-bark-sludge as fuel. In this paper chemical and physical analyses of electrostatic precipitator (ESP) fly ashes were used to explain the differences in the performance of these strategies. These analyses revealed a difference between the coarse and fine fly ashes collected in the ESP. Chemical analysis of the fine fly ashes revealed high concentration of easily volatilized elements while the SEM micrographs showed that fine ash are composed of clusters of spherical particles, thereby leading to a conclusion that fine ashes were originally in a gas phase …
Aeolian Remobilisation of the 2011-Cordón Caulle Tephra-Fallout Deposit: Example of an Important Process in the Life Cycle of Volcanic Ash
2020
Although volcanic eruptions represent short periods in the whole history of a volcano, the large amount of loose pyroclastic material produced, combined with aeolian processes, can lead to continuous, long-lasting reworking of volcanic products. Driven by wind, these processes significantly influence the geomorphology and prolong the impacts of eruptions on exposed communities and ecosystems. Since such phenomena are of interest to scientists from a range of disciplines (e.g., volcanology, atmospheric and soil sciences), a well-defined, common nomenclature is necessary to optimise the multidisciplinary characterisation of both processes and deposits. We, therefore, first describe ash wind-r…
The recent Nyiragongo (Democratic Republic of Congo) eruption: the impact of volcanic ash fallout on drinking water and edible plants
2022
Nyiragongo is an active intraplate volcano well known for its fascinating persistent lava lake inside the crater and is recognized as one of the most dangerous volcanoes in the world as more than two million people live on its slopes, 18-25 km far from the main crater. It is located in the Virunga Volcanic Province (VVP), in the western branch of the East African Rift System (EARS), at the intersection between the Democratic Republic of Congo, Rwanda, and Uganda. Unexpectedly, on 22 May 2021, Nyiragongo produced three different lateral lava flows in the low flanks and significant amounts of volcanic gas and ash were emitted from the summit crater. For several weeks, the ash fallout strongly…