Calcium Oxide Content Research Articles

Major, Minor and Trace Elements Existence in Surface Sediments from Gwadar to Jiwani Coastal Areas of Pakistan

This study was carried out along the western coastal parts of Balochistan from Gwadar east Bay to Jiwani. The local anomaly of major, minor and trace elements were studied in this area. Zone-I (Gwadar east and west Bay) indicates that calcium oxide, potassium oxide and titanium dioxide have higher or average concentrations, while ZoneII indicates higher or average concentrations of calcium oxide, titanium dioxide and ferric oxide. Trace elements zirconium, chromium, europium, strontium, and copper are in higher or average concentrations in both zones. Gwadar west Bay and Jiwani are intermediate in carbonate, which show a high degree of maturity, suggesting the high rate of weathering in the source area. Sediment samples from Ganz, Jiwani, and Gwadar east Bay represent the quartz-rich fields in this region. Gwadar east Bay has a positive correlation between aluminium oxide and potassium oxide which suggests that abundance of potassium oxide is controlled by variation in K-feldspar contents. A positive correlation between strontium and calcium oxide suggests that strontium is associated with calcium oxide in biogenic carbonate material in Gwadar west Bay. The positive correlation between aluminium oxide, copper, and zinc in Pishukan indicates that the abundance of these elements is due to limited silt and clay fractions present in sediments. Enrichment factor shows that chromium and strontium are probably of anthropogenic origin in this region. Keywords

A Model for the Spacing of Quicklime Pile to Treat High Water Content Loess

There has been a long history for foundation treatment by quicklime pile, but as for establishing a more precise model formula used by actual construction, further research is needed to be done at present. Therefore, how to quantitate the factors affecting pile spacing is of great reference value for both actual constructions and theoretical studies. Based on the reference formula for handling weak foundation by lime pile and the practical problems in the western region, mathematical model analysis method is used to get a new model for high water content loess foundation treatment after considering the factors such as pile expanding, construction method, piles arrangement, and calcium oxide content. In this model, pile spacing coefficient is created and the model formula for different construction methods and different pile arrangements is also given. As a result, the reference formula used in high water content loess is somewhat conservative. The new model is also verified to be rational by the actual works at the end of the paper.

Virtual Sensing f-CaO Content of Cement Clinker Based on Incremental Deep Dynamic Features Extracting and Transferring Model

The content of free calcium oxide (f-CaO) in clinker significantly determines the quality of the final cement production. However, in practice, the value of f-CaO content in clinker is off-line sampled manually with a significant time interval and then analyzed in a laboratory with a large time delay, which could meet the needs for monitoring and control of cement quality. To tackle this problem, this article proposes a data-driven model based on deep dynamic features extracting and transferring methods to build a virtual sensor for f-CaO content prediction. First, in this model, large-scale unlabeled data collected from the process distributed control system (DCS) take a vital effect in extracting nonlinear dynamic features along with the limited labeled data samples. Then, the extracted features are transferred to a powerful regression model, the eXtreme Gradient Boosting (XGBoost), for output f-CaO prediction. Besides, an incremental model updating strategy is proposed for the augment of online data samples, which facilitates the virtual sensor to adapt the process time-variant characteristics. Finally, the proposed virtual sensor is verified by a data set acquired from a real cement production process. Comparing with traditional statistical modeling methods, the prediction accuracy of f-CaO content is significantly improved.

Cr(VI) Leached from Lignite Fly Ash—Assessment of Groundwater Contamination Risk

The leaching of Cr(VI) from lignite fly ash was investigated by means of experimental standards and theoretical simulations. Two lignite fly ash samples with different calcium oxide concentration were examined. Acid extraction of fly ash and batch leaching tests were performed at various liquid (water) to solid (fly ash) ratios (L/S) for the estimation of Cr(VI) leaching rate. The mobility of Cr(VI) in soil and soil’s hydraulic conductivity at different temperatures was also examined. The results indicate that chromium in fly ash occurs mainly in its trivalent form and that Cr(VI) can be leached, but at lower degree. Along with Cr(VI), the strong reducing agent Fe(II) is also leached. A portion of the Cr(VI) is readily leached, while several hours are needed for reaching Cr(VI) equilibrium concentration in leachate. The fly ash hydraulic conductivity is greatly affected by its pozzolanic characteristics, decreasing from around 10 mm/h (2.78 × 10−6 m/s) to values lower than 1 mm/h (2.78 × 10−7 m/s) in few hours. In continuous leaching tests, relatively low Cr(VI) concentrations (< 20 μg/L) were detected, while in batch leaching tests with higher water/fly ash contact time, leachate Cr(VI) concentrations up to 700 μg/L were detected depending on the applied L/S ratio. However, for low L/S (0.5–1) ratios, no leachate was obtained. Theoretical calculations were performed in order to estimate the L/S ratios at real conditions (by taking into account the volume and the surface of an ash disposal, the density of ash, the hydraulic conductivity of ash, rainfall rate, and rainfall duration). It was found that in real conditions, high L/S can be obtained only when various specific conditions are fulfilled. Experiments with soil showed that only a small portion (approximately 4%) of the leached Cr(VI) can pass through a relatively thin (12–15 cm) layer of soil, even at low temperatures. Based on the experimental results and the groundwater and surface water quality data of a studied basin, a low contamination risk due to Cr(VI) leaching from lignite fly ash is assessed.

Sorption enhanced steam methane reforming by Ni/CaO/mayenite combined systems: Overview of experimental results from European research project ASCENT

AbstractWork Package 4 (WP4) of the European research project ASCENT developed combined sorbent‐catalyst materials (CSCM) for sorption enhanced steam methane reforming (SESMR), based on nickel (Ni) and calcium oxide (CaO). This work summarizes the whole experimental study carried out in ASCENT WP4 on Ni/CaO/mayenite systems obtained from wet mixing and wet impregnation synthesis methods. Effects from Ni precursor (Ni (CH3COO)2 · 4H2O or Ni(NO3)2 · 6H2O), Ni load (from 3 wt%‐10 wt%), and free CaO load (from 0 wt%‐54 wt%) were investigated for 26 materials by means of characterizations and reforming reactivity tests in a packed‐bed microreactor (650°C, 1 atm). Thanks to comparative analyses of the results, evidence emerged about the detrimental influence of low Ni/CaO ratio on the reforming catalytic activity of solid inventories, made of CSCM or even of the raw mixing of CaO‐mayenite and Ni‐mayenite particles. Catalytic materials were active towards reforming only when derived from Ni(NO3)2 · 6H2O. Based on this, the best CSCM (with the lowest free CaO content and the highest Ni load from nickel nitrate) was chosen to further study its industrial applicability by multicycle SESMR/sorbent‐regeneration tests in a bench‐scale packed‐bed rig and attrition tests according to ASTM D5757‐11. The CSCM was stable and active for 200 cycles with regenerations in N2 at 850°C, while a progressive loss of its activity occurred with regenerations in CO2 at 925°C as the cycle number increased due to Ni sintering. Its performance in the attrition tests was comparable to that of calcined dolomite.

Effect of calcium oxide on mechanical properties and microstructure of alkali-activated slag composites at sub-zero temperature

Alkali-activated slag (AAS) has the potential to be applied in winter construction due to its continuous hydration at subzero temperature. However, to further enhance the mechanical properties of AAS as structure repair material in cold regions, calcium oxide (CaO) at proportions of 1 wt%, 2 wt%, 3 wt% and 4 wt% were incorporated as partial replacement of ground granulated blast furnace slag (GGBS) in AAS. An appropriate CaO content of 3 wt% was determined based on the setting time and mechanical testing, and the results showed that it increased the compressive and flexural strength of AAS by 40% and 48% at the age of 1 day and by 5% and 7% at the age of 28 days at a temperature of −10 °C. Moreover, semiadiabatic calorimetry, attenuated total reflection Fourier transform infrared spectroscopy, mercury intrusion porosity and scanning electron microscope measurements were carried out on typical samples. Experimental results showed that the hydration heat was enhanced and the generation ratio of C(-A)-S-H was increased by incorporation of CaO into AAS. Furthermore, the pore structure was refined and porosity was decreased for AAS with CaO incorporated. Finally, the proposed mechanism explanation of CaO to enhance the strength of AAS was determined by comparing the ATR-FTIR test results of 3 wt% CaO modified AAS sample and 3 wt% Ca(OH)2 modified AAS sample cured at −10 °C for 1 day.

Recovery of iron from copper slag via modified roasting in CO–CO2 mixed gas and magnetic separation

A novel technology, modified roasting in CO–CO2 mixed gas and magnetic separation, was presented to recover iron from copper slag. The effects of various parameters such as dosage of flux (CaO), gas flowrate of CO and CO2, roasting temperature, roasting time, particle size of modified slag and magnetic flux density on the oxidized modification and magnetic separation were investigated by comparison of the X-ray diffraction patterns and iron recovery ratio. The optimum conditions for recovering iron by oxidizing roasting and magnetic separation are as follows: calcium oxide content of 25 wt.%, mixed gas flow rates of CO2 and CO of 180 and 20 mL/min, oxidizing roasting at 1323 K for 2 h, grinding the modified slag to 38.5–25.0 μm and magnetic separation at 170 mT. The mineralogical and microstructural characteristics of modified slag revealed that the iron-bearing minerals in the copper slag were oxidized, the generated magnetite grew into large particles, and the silicate in copper slag was combined with calcium oxide to form calcium silicate. Finally, the iron-bearing concentrate with an iron grade of 54.79% and iron recovery ratio of 80.14% was effectively obtained.

CARACTERÍSTICAS FÍSICAS, QUÍMICAS E FÍSICO-QUÍMICAS DE CALCÁRIO EXTRAIDO DO SULDOESTE DA REGIÃO AMAZÔNICA

O presente trabalho tem por objetivo, analisar a concentração de cálcio, magnésio, Poder de Neutralização, Reatividade e Poder Relativo de Neutralização Total em calcário da região Norte. Foram determinados os teores totais de óxidos de cálcio (CaO) e magnésio (MgO) por volumetria utilizando o EDTA (ácido etilenodiaminotetracético) como agente complexante, solução tampão em pH = 10, e como indicador complexométrico, o corante orgânico Negro de eriocromo T. As análises foram realizadas em dez amostras de calcários, em que cada amostra corresponde a jazidas distintas. As amostras encontram-se dentro dos parâmetros que as classificam como calcário. Na classificação pelo teor de MgO, constatou-se que, das dez amostras analisadas, todas podem ser classificadas como calcário dolomítico, além de apresentar as quantidades mínimas de PRNT admitidas pela legislação.

The surface coating mechanism of polluted concrete by Candida ethanolica induced calcium carbonate mineralization

This paper documents the laboratory evidence on the mineralization mechanism of Candida ethanolica for surface coating of concrete with polluted sand as fine aggregate. C. ethanolica is largely discovered as a waste microbe in the beer industry. The tendency of the microbe to cultivate easily and induce bio-crystals with the capability to encapsulate heavy metals; has made it mesmerizing to be explored in a sustainable manner for concrete surface coating technology. Under the influence of the optimal initial pH, calcium oxide concentration, and fungal cell concentration in the liquid growth media; the treated concrete cubes were experimented to have an average 28-day compressive strength of 32.20 MPa. Such strength value is 6.27% higher when compared to that of the untreated concrete cubes at the same curing time. Overall, the findings revealed that the fungal bio-crystals have a promising prospect to be applied as a concrete surface coating.

Durability Aspects of Chemically Stabilized Quarry By-Product Applications in Pavement Base and Subbase

Recent research conducted at the Illinois Center for Transportation evaluated sustainable applications of quarry by-products (QB) or QB blended with coarse recycled aggregates in chemically stabilized base and subbase layers in flexible pavements and proved that stabilized QB pavement applications show satisfactory pavement performance. This paper investigates the durability aspects of the evaluated QB applications, particularly in relation to freezing–thawing cycles during winter and wetting–drying conditions. Durability tests were conducted on samples extracted from field test sections previously evaluated with accelerated pavement testing (APT) as well as on new samples prepared in the laboratory with the same QB types and material combinations. Field-extracted samples were exposed to multiple cycles of freezing and thawing and wetting and drying throughout APT. Both sets of samples were evaluated by AASHTO T 135 and AASHTO T 136 for wet–dry and freeze–thaw durability, respectively. The results of durability testing indicated that cement-stabilized QB materials benefited from the long-term curing in the field, whereas fly ash-stabilized QB materials were less durable after exposure to multiple freeze–thaw and wet–dry cycles in the field. Field samples compacted at or near the maximum dry density (i.e., having higher relative densities) consistently showed better performance for durability. Further, durability samples made with QB materials from dolomitic aggregate sources, having higher magnesium oxide content in chemical composition, showed better field performances than those with limestone QB having high calcium oxide content. This was possibly linked to cementation observed in the dolomitic QB applications after being exposed to freeze–thaw cycles in three winters.

Remediation of Cobalt-Contaminated Soil Using Manure, Clay, Charcoal, Zeolite, Calcium Oxide, Main Crop (Hordeum vulgare L.), and After-Crop (Synapis alba L.)

This study was undertaken to determine the effects of various substances on soil contaminated with cobalt (Co) on the mass and content of cobalt in the main crop—spring barley (Hordeum vulgare L.)—and the after-crop—white mustard (Synapis alba L.). Manure, clay, charcoal, zeolite, and calcium oxide were used for phytostabilization. Cobalt was applied in the form of CoCl2 in doses of 0, 20, 40, 80, 160, and 320 mg/kg soil. Amendments in the form of manure, clay, charcoal, and zeolite were applied in an amount of 2% in relation to the weight of the soil in a pot, with calcium oxide at a dose of 1.30 g CaO/kg of soil. The highest cobalt doses resulted in a significant reduction in yield of both plants and in tolerance index for cobalt. Increasing contamination of soil with cobalt resulted in a major and significant increase in its content in plants and a reduction in cobalt translocation factor in both plants. Amendments used in phytostabilization had a significant effect on growth and development of oat and content of cobalt in plants. The strongest effect on the yield of above-ground parts was exerted by manure (both plants) and calcium oxide (white mustard), while the strongest effect on weight of roots was exerted by calcium oxide (both plants) and zeolite (white mustard). The addition of manure, zeolite and calcium oxide to soil caused an increase of the tolerance index for both plants, while the addition of clay only had a positive effect for white mustard. All substances used in phytostabilization (except zeolite) decreased cobalt content of roots, and manure and calcium oxide in above-ground parts of spring barley; manure and zeolite only in above-ground parts, and calcium oxide in both organs of white mustard. Most of them also reduced bioconcentration of cobalt in above-ground parts, calcium oxide decreased cobalt content in roots of both plants, and manure in roots of spring barley. The effect on cobalt translocation was less clear, but most substances used in phytostabilization increased the transfer of cobalt from the soil to plants. White mustard had higher ability to accumulate cobalt than spring barley.

Production of Methyl Ester from Soybean Oil by Using Impregnated Mixed Domestic-Waste Catalysts

Nowadays due to the depletion of non-renewable energy resources, production of green material from domestic wastes has played an important role. The waste of banana peel impregnated with calcium oxide (CaO) from eggshell had successfully been used as a low-cost catalyst to transesterify soybean oil to produce methyl ester. The catalytic actions from potassium and calcium oxide content in calcined banana peel (700 °C) and eggshell (900 °C) discover through FT-IR, XRD, and SEM. Production of methyl ester obtained at 82.29 wt. % with the optimal condition of 7 wt. % of catalyst amount, methanol/oil mass ratio, 9:1; and the reaction temperature, 65 °C within 2 h reaction time.

Assessment of two sludge stabilization methods in a wastewater treatment plant in Sotaquirá, Colombia

Wastewater sludge is a by-product of waste water treatment; it is often employed in agricultural processes following appropriate microbiological stabilization. In this study, we evaluated two methods of sludge stabilization in the waste water treatment plant of Sotaquirá, Colombia. The two assessed stabilization methods were dewatering on drying beds and alkaline stabilization. The stabilization through dewatering on drying bed was carried out for five months. Alkaline stabilization was conducted for 96 hours with three concentrations of calcium oxide, 7%, 9%, and 13% w/w. Humidity, pH, organic carbon, phosphorus, organic nitrogen, fecal coliforms, somatic phages, total helminth eggs, and Salmonella sp. were monitored monthly for the sludge under dewatering treatment and at 0, 12, 24 hours for sludge under alkaline stabilization treatment. Both treatments succeded in eliminating Salmonella sp. Helminth eggs were eliminated by alkaline stabilization, whereas it was reduced to one or zero helminth eggs with the dewatering treatment. Somatic phages were eliminated with alkaline stabilization but were only reduced to 3.52 log CFU/g with the dewatering method. Dewatering on drying beds produced biosolids that can be used for soil restoration. Whereas alkaline stabilization produced biosolids that can be used for agricultural purposes. Alkaline stabilization with 9% and 13 % calcium oxide ostensibly reduced nitrogen and phosphorus contents in the sludge, whereas 7 % calcium affected less the phosphorus concentration of the sludge. These results indicate that sludge dewatering on drying beds is an effective sludge sanitation protocol to be implemented in small waste water treatment plants, such that in Sotaquirá, Colombia.

Effects of calcium oxide on the surface properties of industrial sludge by analyzing rheological and electrical properties

Rheological properties in the dynamic regime and complex conductivity measurements were performed on the wastewater sample containing different calcium oxide content. The complex viscosity (η*), the elastic (G’) and loss moduli (G’’) exhibited a linear behavior as a function of angular frequency. These rheological properties were well described by a power-law. Therefore; The values of G’0, G’’0 and η0 corresponding to angular frequency (ω = 1 rad/s) were extracted. Their evolution as a function of calcium oxide content showed that there is a critical amount of calcium oxide content (3 %), from which these parameters showed a net transition indicating the existence of two regions. Similar behavior has been observed from the analysis of the complex conductivity. The hopping conductivity, the ionic strength and the associated relaxation time showed also a net transition at (3 %). A conductivity relaxation behavior was observed in the high frequency and a more detailed analysis of such behavior is reported. This behavior was attributed to the localized relaxation process due to the short-range hopping motion of ions trapped inside the aggregations. The evolutions of the rheological and the electrical properties were analyzed by an equation including two power laws. This equation was able to fit very well their evolution as well to predict the optimal amount of calcium oxide (3 %) needed to achieve the coagulation process.

Determining the risk of calcium oxide (CaO) particle exposure to marine organisms

Calcium oxide (CaO) is being considered as a possible treatment for both the control of echinoderm populations and the treatment against sea lice infestation in Norwegian salmon farms. CaO particles produce an exothermal reaction when in contact with water, which can cause epidermal burns and lesions to certain target organisms leading to death. The aim of the present study was to determine the effects of fine (<0.8 mm) and coarse (<2.5 mm) CaO particles to a range of marine species from different taxonomic groups: two echinoderms (Asterias ruben and Strongylocentrotus droebachiensis); two crustaceans (Carcinus maenas and Tisbe battagliai); two molluscs (Mytilus edulis and Hinia reticulata); a polychaete (Nereis pelagica); a fish (Cyclopterus sp.); and seaweed germlings (Fucus vesiculosus). Overall, the fine CaO particles were more toxic to the selected marine species than the coarse particles. Coarse CaO particle effects were only observed in four of the nine species tested (A. rubens, S. droebachiensis, N. pelagica, T. battagliai) with similar LC50 values between 207 and 268 g/m2. For the fine CaO particles, the lowest LC50 was for the epibenthic copepod (T. battagliai) at 3.14 g/m2, followed by the sea urchin (20.1 g/m2), starfish (22.2 g/m2), ragworm (29.6 g/m2), and netted dog whelk (41.9 g/m2). Lump sucker fish exhibited significant mortalities only at the highest fine CaO concentration tested (320 g/m2) and recorded an LC50 of 226 g/m2. The toxicity data were used to generate species sensitivity distributions (SSDs) for both fine and coarse CaO particles. The hazard concentrations for 5% of the species (HC5) calculated from the SSDs, based on NOEC values, for the coarse and fine particles were 35.5 and 1.5 g/m2 respectively. Using a recommended assessment factor of 5, the Predicted No Effect Concentration (PNEC) was calculated as 7.1 and 0.3 g/m2 for coarse and fine CaO particles respectively.

Effect of Calcium Oxide on the Structure and the Thermal Properties of Granulated High-Iron Slags

The effect of calcium oxide (3.5–11.1%) on the microstructure, the elemental composition, and the microhardness of the phases that form during the water granulation of the molten slags having formed in autogenous smelting of copper–zinc concentrates is studied by metallography, X-ray diffraction, and electron-probe microanalysis. The slag granulation leads to the formation of an amorphous component, the amount of which decreases with increasing calcium oxide content. Copper, lead, and arsenic in the slags are mainly in the form of sulfide inclusions, and zinc is present in both sulfides and oxides. The introduction of calcium oxide in the slags (up to 11.1%) promotes coarsening of sulfide inclusions and an increase in the microhardness of the silicate phases. Differential scanning calorimetry is used to determine the thermal properties of the slags, namely, the temperatures and heats of devitrification, “cold crystallization” of amorphous phases, melting, and solidification. The results obtained can be used to choose slag cooling conditions and to prepare slags for the extraction of valuable metals by beneficiation methods.

Relationship between operational properties of peat heat-insulating materials and the content of mineral binders in them

This work presents the main results of calculation and experimental study on relation between the operational properties of peat heat-insulating materials (HIM) and the content of mineral binders in them aiming at reducing heat energy costs by energy-consuming objects. It was experimentally proved that introduction of cement increases thermal conductivity, and introduction of calcium oxide as a mineral binder, on the contrary, promotes the development of material porosity while maintaining strength characteristics and elasticity and helps to reduce the thermal conductivity and specific density. The established relationship between the content of calcium oxide and the thermal conductivity enables modelling of technology for HIM producing based on peat and inorganic binders.

Accelerated Carbonation Assessment of High-Volume Fly Ash Concrete

The issue of concrete carbonation has gained importance in recent years due to the increase use in supplementary cementing materials (SCMs) in concrete mixtures. While there is general agreement that concrete carbonation progresses at maximum at a relative humidity of about 60%, the rate may differ in the case of cements blended with SCMs, especially with high-volume fly ash replacements. In this study, the effect of high-volume fly ash concrete exposed to low ambient relative humidity (RH) conditions (57%) and accelerated carbonation (4% CO2) is investigated. Twenty-three concrete mixtures were produced varying in cementitious contents (310, 340, 370, and 400 kg/m3), water-to-cementitious materials ratio (0.45 and 0.50), and fly ash content (0%, 15%, 30%, and 50%) using a low and high-calcium fly ash. The specimens were allowed 1 and 7 days of moist curing and monitored for their carbonation rate and depth through phenolphthalein measurements up to 105 days of exposure. The accelerated carbonation test results indicated that increasing the addition of fly ash also led to increasing the depth of carbonation. Mixtures incorporating high-calcium fly ash were also observed to be more resistant against carbonation than low-calcium fly ash due to the higher calcium oxide (CaO) content. However, mixtures incorporating high-volume additions (50%) specimens were fully carbonated regardless of the type of fly ash used. It was evident that the increase in the duration of moist curing from 1 day to 7 days had a positive effect, reducing the carbonation depth for both plain and blended fly ash concrete mixes, however, this effect was minimal in high-volume fly ash mixtures. The results demonstrated that the water-to-cementitious ratio (W/CM) had a more dramatic impact on carbonation resistance than the curing age for mixtures incorporating 30% or less fly ash replacement, whereas those mixtures incorporating 50% showed minor differences regardless of curing age or W/CM. Based on the compressive strength results, carbonation depth appeared to decrease with increase in compressive strength, but this correlation was not significant.

Biogasoline synthesis via fluid catalytic cracking of waste cooking oil using treated eggshell

This paper reports on preparation and characterization of eggshell for fluid catalytic cracking (FCC) reaction of waste cooking oil (WCO) to produce biogasoline. Hydrocarbon from condensate of gas emitted from a spherical flask reactor was agitated at 350, 400 and 450 resolution per minute (rpm) under 350, 400 and 450 °C reaction temperature by the one-factor- at-a-time (OFAT) approach was analyzed by using a gas chromatography mass spectrometer (GC-MS). Acid compounds were also recorded. Earlier, the eggshell was ground, calcined at 900 °C for three hours and sieved into 250 – 425 μm range of particle size before being analyzed using Fourier-transform-infrared-spectroscopy (FTIR) for calcium oxide content. About 30 wt% of biogasoline ranged from C4 to C12 of alkanes and alkenes was obtained from the 350-°C hydrocarbon condensate after 30, 45 and 60 min of which aromatic compounds increased with the reaction temperature. However, the biogasoline compounds decreased with the reaction temperature. More than 20 wt% was esters and free fatty acids of carbon number greater than 20 were also formed, respectively. Stirring speeds generally increased condensate yield but the increment does not have pattern due to various volatility of the content. The highest biogasoline yield through the FCC reaction was 4.5 wt% at 350 0C at 400 rpm stirring speed, and the product was found comparable with previous research and commercial gasoline.

Surfactant-assisted sol–gel synthesis of mesoporous bioactive glass microspheres

Spherical mesoporous bioactive glasses in the silicon dioxide (SiO2)–phosphorus pentoxide (P2O5)–calcium oxide (CaO) system with a high specific surface area of up to 300 m2/g and a medium pore radius of 4 nm were synthesized by using a simple one-pot surfactant-assisted sol–gel synthesis method followed by calcination at 500–700°C. The authors were able to control the particle properties by varying synthesis parameters to achieve microscale powders with spherical morphology and a particle size of around 5–10 μm by employing one structure-directing agent. Due to a high calcium oxide content of 33·6 mol% and a phosphorus pentoxide content of 4·0 mol%, the powder showed very good bioactivity up to 7 d of immersion in simulated body fluid. The resulting microspheres are promising materials for a variety of life science applications, as further processing – for example, granulation – is unnecessary. Microspheres can be applied as materials for powder-based additive manufacturing or in stable suspensions for drug release, in bone cements or fillers.