Relationship between composition and structure of globules in narrow fractions of ferrospheres

Catalytic properties and nature of active centers of ferrospheres in oxidative coupling of methane

“…For those with a higher Fe 2 O 3 content (> 85 wt%), the CaOpromoted ferrite spinel and the hematite phases were identified. The former had the unit cell parameter exceeding the corresponding parameter of stoichiometric magnetite, while the latter had the unit cell parameters close to those of stoichiometric α-Fe 2 O 3 [16,17]. According to our previous study [18], the ferrospheres with the aluminum-magnesium-ferrite spinel are not selective OCM catalysts, yielding CO x mainly.…”

“…The ferrospheres of series B(n) and S(n) were separated from ferrisialic type fly ash from combustion of coal Tugnuisky Deposit (Buryatia) and the calsialic type fly ash from combustion of coal Berezovsky Deposit (Krasnoyarsk region), respectively. The chemical and phase composition, morphology of the globules, and microstructural characteristics of the initial B and S series were studied in detail in our previous study [16,17]. The ferrospheres of the SMF series were obtained from fractions −0.05 and −0.063+0.05 mm of the S series by the grain-size classification and separation in a gradient magnetic field.…”

“…The former materials have been thoroughly characterized in our previous study [16]. To preserve the catalyst composition formed under the OCM conditions, the catalysts after the catalytic tests at 750°C were rapidly (150-200/min) quenched in the OCM feed before XRPD analysis.…”

“…Contrarily, ferrospheres and magnetic cenospheres with a lower iron content oxidized methane to carbon oxides [14,15]. In order to elucidate possible fundamental reasons for the different OCM performance, we thoroughly characterized ferrospheres with the content of Fe 2 O 3 in the range of 30-92 wt% to determine their composition, morphology, microstructure of iron-containing phases, and catalytic properties [16][17][18]. In particular, it was demonstrated that the aluminum-magnesiumferrite spinel is the main phase in ferrospheres with the content of Fe 2 O 3 lower than 80 wt% and high concentration of SiO 2 and Al 2 O 3 .…”

Characterization of Aerodynamically Separated Products of Fly Ash Produced via the Pulverized Combustion of Coal from Kuznetsk Basin

“…В последние годы повышенный интерес вызывают разработки на основе отдельных компонентов зол функциональных материалов с заданными свойствами (адсорбентов, катализаторов, носителей, керамических материалов, цеолитов) [4,6]. Так, вы-деление из зол-уноса узких фракций микросфер определенного размера в интервале 50-250 мкм с постоянным химическим и минерально-фазовым составом [18][19][20][21] позволило получить высокоселективные мембраны для диффузионного выделения гелия и контейнеры для хра-нения водорода [22][23][24], эффективные катализаторы для процессов окисления метана [25,26], крекинга тяжелой нефти, мазутов и битумов [27,28], сенсибилизаторы эмульсионных взрывча-тых веществ [29], магнитоуправляемые капсулированные рН-чувствительные спиновые зонды для исследования биологических объектов [30], магнитные аффинные сорбенты типа «ядро-оболочка» для выделения рекомбинантных белков [31,32], композитные сорбенты для извле-чения радионуклидов из жидких радиоактивных отходов [33][34][35].…”