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The mineral matter contained in feedstocks has a generally limiting impact on the process design of high-temperature conversion processes. In the present study, the composition, mineral phases, and process-relevant properties of ashes are investigated by different experimental and modeling methods, which were reviewed in the literature regarding the frequently applied methods. Various analyses are exemplarily performed for the ashes of a high-sodium coal from China, generated at temperatures of 150â950 °C. X-ray fluorescence (XRF) analysis, microwave-assisted inductively-coupled plasma optical emission spectrometry (MW-ICP-OES), and the same technique with electrothermal vaporization (ETV-ICP-OES) are applied to analyze the chemical composition of the bulk material. The chemical composition of the near-surface region is studied by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Mineral phases are analyzed by X-ray diffraction (XRD) a nd thermochemical calculations. The process-relevant ash fusion behavior is studied by a common ash fusion test (AFT) and thermomechanical analysis (TMA) and supported by thermochemical calculations. The different ashing temperatures have a recognizable impact on the composition, formation and transformation of mineral phases, and resulting ash fusion behavior, while each property is monitored by at least two different methods. For this purpose, a detailed analysis of the results achieved by the individual methods is performed. Finally, the results obtained by different methods for the same ash property are compared for monitoring the validity of the results and, for example, extracting additional information about the gas phase transfer of selected ash components.

For now, the Planetary Defense Conference Exercise 2021's incoming fictitious(!) asteroid, 2021 PDC, seems headed for impact on October 20th, 2021, exactly 6 months after its discovery. Today (Monday, April 26th, 2021), the impact probability is 5%, in a steep rise from 1 in 2500 upon discovery six days ago. We all know how these things end. Or do we? Unless somebody wants to keep civil defense very busy very soon, the chance is 95% that it will not hit; instead fly by closely to Earth, swing by to a new orbit that takes it away essentially forever or back again sooner or later through a keyhole, for a re-play at different odds. This is where our story starts and the story sounds familiar: season's greetings from 2004 MN4, now better known as (99942) Apophis. One more thing is similar: the close fly-by is an easy launch opportunity to 'jump aboard' that potentially hazardous asteroid for planetary science and tracking of longterm Yarkovsky-shifted keyhole resonant return risks. Indeed, missions are currently being discussed to launch during the 2029 fly-by of Apophis to rendezvous and investigate it closely right after. Others strive for an earlier launch to rendezvous well before, to observe all of the close fly-by at Earth and what it might do to a likely delicate rubble pile asteroid. Presently, this is an unlikely if not impossible option for sudden encounters like 2021 PDC with a lead time of months. But when asteroid mining (...possibly the other ...-not-if of asteroids?) takes off in the same manner as low Earth orbit communications satellites, this option may become a reality. But for now, even if a suitable planetary mission were serendipitously ready atop a suitable launch vehicle, could you get it an asteroid lander within 6 months? Surprisingly, this option existed between late 2014 and late 2018 when the MASCOT Qualification Model turned Flight Spare was kept fully integrated and flight ready for on-ground testing to prepare for the Flight Model's brief but complete mission on Ryugu with JAXA's highly successful HAYABUSA2 probe. At the same time, the MASCOT2 detailed design study for ESA's former AIM mission within the common NASA-ESA AIDA mission to (65803) Didymos and its moonlet, Dimorphos (then affectionately known as 'Didymoon'), paved the way for long-life MASCOTs, many of which have been discussed and studied since. The thoughtful design of MASCOT’s hardware and software allowed for a very high degree of re-use and flexibility regarding scientific payloads. MASCOT2 was to investigate the interior of Didymoon by Low-Frequency Radar. Close encounters like Apophis' offer unique opportunities for Earth-based planetary radar assets to work with spacecraft near and landers on the passing asteroid. We present a range of options for radar- and composition-oriented long-life MASCOT variants - to be delivered to the surfaces of the respective asteroid bodies - for the presently most likely near miss of 2021 PDC and the most certain close fly-by of (99942) Apophis on Friday, April 13th, 2029.

Slagging-type technologies, particularly entrained-flow gasification, have been quickly developed and industrialized due to their inherent advantages. The ashes of many feedstocks are rich in SiO2 and Al2O3. Therefore, a high operating temperature is required, making the process less efficient. The use of pure additives such as limestone does not meet the requirements. In consequence, binary additives of CaO/Fe2O3 are studied to improve the fusibility. The CaO/Fe2O3 ratio is varied in order to optimize cost efficiency and the operation and control of processes. Ash fusion temperatures (AFTs) and X-ray diffraction (XRD) combined with in-situ methods of thermomechanical analysis (TMA) and high-temperature scanning electron microscopy (HT-SEM) are used to explore the effect of CaO/Fe2O3 on ash fusibility. The CaO/Fe2O3 ratio affects the ash fusion behavior due to changes in the mineral phase composition. The AFTs reveal an optimum combination for the joint addition of CaO and Fe2O3 compared to blends with the same amount of one single additive, while sintering is less strongly affected. Based on the in-situ analyses, the blends of ash and additive are categorized into two or three regimes of sintering, swelling, and fusion in the high temperature range. Depending on the applied additive ratio, different regimes of ash fusion are detected, which affect the slag properties.

Biomasses are a promising way to reduce the CO2 emissions in many industrial processes for the generation of energy and chemical base materials. To enable them to be used in related thermochemical conversion processes, their thermal behaviour and ash properties, which are the main limiting factors, must be investigated. In the present study, four feedstocks from two types of biomass are studied. The thermal behaviour is determined by thermal gravimetry (TG), differential thermal gravimetry (DTG), and differential scanning calorimetry (DSC) analysis. Comparable behaviour with only minor deviations is achieved for all biomass samples, which is largely independent of the exact properties of the feedstocks. The key goal of this work was to compare the properties of ashes obtained under 550 °C (standard procedure) and 200 °C (using plasma). Chemical analysis (applying X-ray fluorescence method) indicates the differences in the ash composition even in the particular types of biomass. Scanning electron microscopy (SEM-EDX) reveals that the composition is heterogeneously distributed over the different ash particles. Based on the different ashing temperatures, the transformation of the mineral phases in real conversion processes determined by X-ray diffraction (XRD) is simulated. Despite the heterogeneities in the ash particles' chemical composition and distribution within each particular type of biomass, they demonstrate highly similar ash fusion temperatures. The thermochemical calculations using the FactSageTM software package have well reflected the ash fusion temperatures and the ash fusion interval.

On Earth most definitely and likely also around the Moon, in the few days centred on Friday, April 13th, 2029, 21:45 UT, every informed and curious naked eye, lens, mirror and dish within the horizon will be aimed at (99942) Apophis for an once-in-a-1000 years opportunity of scientific observations. Most will watch or listen. Many will transmit. Some will get in the way of others. And a few will blast it with all they can - for the best of science. We intend to start the discussion to include the public in the unique observation of Apophis, in particular focusing on the radio amateur community and the need for world-wide coordination to avoid mutual interference.