231,231 research outputs found
Influences of CaO-Al2O3 Interaction on Coke Resistance of CaO Modified Pt/Al2O3 Catalyst
No full textInfluences of CaO-Al2O3 interaction on catalyst coke resistance were studied by adjusting calcination temperatures. The catalyst calcined at 600 °C exhibits the worst, while the one calcined at 800 °C shows the best coke resistance among the catalysts calcined at different temperatures. High activity (86 %) and high stability for cyclohexane dehydrogenation during 220 h investigation are obtained. This is attributed to strong Ca-Al interaction and relatively large CaO particles, which lead to more dispersed Pt and larger amount of spilt-over H2. Models of Ca-Al interactions are established, exhibiting the variations of CaO particles and the formation of calcium aluminates
Melt densities in the CaO-FeO-Fe2O3-SiO2 system and the compositional dependence of the partial molar volume of ferric iron in silicate melts
No full textThe densities of 10 melts in the CaO-FeO-Fe2O3-SiO2 system were determined in equilibrium with air, in the temperature range of 1200 to 1550°C, using the double-bob Archimedean technique. Melt compositions range from 6 to 58 wt% SiO2, 14 to 76 wt% Fe2O3 and 10 to 46 wt% CaO. The ferric-ferrous ratios of glasses drop-quenched from loop fusion equilibration experiments were determined by 57Fe Mössbauer spectroscopy.
Melt densities range from 2.689 to 3.618 gm/cm3 with a mean standard deviation from replicate experiments of 0.15%. Least-squares regressions of molar volume versus molar composition have been performed and the root mean squared deviation shows that a linear combination of partial molar volumes for the oxide components (CaO, FeO, Fe2O3 and SiO2) cannot describe the data set within experimental error. Instead, the inclusion of excess terms in CaFe3+ and CaSi (product terms using the oxides) is required to yield a fit that describes the experimental data within error. The nonlinear compositional-dependence of the molar volumes of melts in this system can be explained by structural considerations of the roles of Ca and Fe3+.
The volume behavior of melts in this system is significantly different from that in the Na2O-FeO-Fe2O3-SiO2 system, consistent with the proposal that a proportion of Fe3+ in melts in the CaO-FeO-Fe2O3-SiO2 system is not tetrahedrally-coordinated by oxygen, which is supported by differences in 57Fe Mössbauer spectra of glasses. Specifically, this study confirms that the 57Fe Mössbauer spectra exhibit an area asymmetry and higher values of isomer shift of the ferric doublet that vary systematically with composition and temperature (this study; Dingwell and Virgo, 1987, 1988). These observations are consistent with a number of other lines of evidence (e.g., homogeneous redox equilibria, Dickenson and Hess, 1986; viscosity, Dingwell and Virgo, 1987,1988). Two species of ferric iron, varying in proportions with temperature, composition and redox state, are sufficient to describe the above observations.
The presence of more than one coordination geometry for Fe3+ in low pressure silicate melts has several implications for igneous petrogenesis. The possible effects on compressibility, the pressure dependence of the redox ratio, and redox enthalpy are briefly noted
CaO-Promoted Lattice Oxygen Activation and Antichlorine Poisoning over Mullite for Catalytic Chlorobenzene Combustion
No full textThe degradation of chlorine-containing
volatile organic
compounds
(Cl–VOCs) utilizing catalytic combustion technology is subject
to the paradox of toxic byproduct formation and catalyst chlorine
poisoning. Herein, a CaO-assisted strategy is proposed to resolve
the awkward stuff for improving the catalytic combustion performance
of chlorobenzene on SmMn2O5. The CaO-collaborated
SmMn2O5 exhibits a significant decrease in T90 by 142 and 125 °C compared with unmodified
and inert SiO2-composited SmMn2O5, respectively. The integrated characterization results confirm that
CaO collaboration causes electron transfer from CaO to SmMn2O5, resulting in a reduction of the orbital overlap between
Mn and O atoms to activate lattice oxygen (Olatt). The
activated Olatt enables chlorobenzene to combust completely
at a lower temperature of 275 °C at which toxic byproducts are
not generated. Furthermore, the switching of the dechlorination site
from SmMn2O5 to CaO avoids chlorine poisoning
of active sites on SmMn2O5 and thus endows CaO-collaborated
SmMn2O5 with prominent stability
Process engineering and development of post-combustion CO2 separation from fuels using limestone in CaO-looping cycle
No full textGlobal CO2 emissions produced by energy-related processes, mainly power plants, have increased rapidly in recent decades; and are widely accepted as the dominant contributor to the greenhouse gas (GHG) effect and consequent climate changes. Among countermeasures against the emissions, CO2 capture and storage (CCS) is receiving much attention. Capture of CO2 is the core step of CCS as it contributes around 75% of the overall cost, and may increase the production costs of electricity by over 50%. The reduction in capture costs is one of the most challenging issues in application of CCS to the energy industry. Using limestone in CaO-looping cycles is a promising capture technology to provide a cost-effective separation process to remove CO2 content from power plants operations. Limestone has the advantage of being relatively abundant and cheap, and that has already been widely used as a sorbent for sulphur capture. However, this technology suffers from a critical challenge caused by the decay in the sorbent capture capacity during cyclic carbonation/calcination, which results in the need for more sorbent make-up; hence a reduction in cost efficiency of the technology. The performance of sorbent influenced by several operating and reaction conditions. Therefore, much research involves investigation of influencing factors and different methods to reduce the sorbent deactivation. Cont/d
Novel sol–gel preparation of (PO)–(CaO)–(NaO)–(TiO) bioresorbable glasses (X = 0.05, 0.1, and 0.15)
No full textQuaternary phosphate-based glasses in the PO–CaO–NaO–TiO system with a fixed PO and CaO content of 40 and 25 mol% respectively have been successfully synthesised via sol–gel method and bulk, transparent samples were obtained. The structure, elemental proportion, and thermal properties of stabilised sol–gel glasses have been characterised using X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), P nuclear magnetic resonance (P NMR), titanium K-edge X-ray absorption near-edge structure (XANES), fourier transform infrared (FTIR) spectroscopy, and differential thermal analysis (DTA). The XRD results confirmed the amorphous nature for all stabilized sol–gel derived glasses. The EDX result shows the relatively low loss of phosphorus during the sol–gel process and Ti K-edge XANES confirmed titanium in the glass structure is in mainly six-fold coordination environment. The P NMR and FTIR results revealed that the glass structure consist of mainly Q and Q phosphate units and the Ti cation was acting as a cross-linking between phosphate units. In addition DTA results confirmed a decrease in the glass transition and crystallisation temperature with increasing NaO content. Ion release studies also demonstrated a decrease in degradation rates with increasing TiO content therefore supporting the use of these glasses for biomedical applications that require a degree of control over glass degradation. These sol–gel glasses also offer the potential to incorporate proactive molecules for drug delivery application due to the low synthesis temperature employed
Kapsa (Rigida) Cao & Zhang
No full textKey to males of Kapsa (Rigida) Cao & Zhang sgen. n. 1. Anal tube appendage rudimentary, small, not hooked at apex...................... K. apicispina Yang & Zhang sp. nov. - Anal tube appendage well developed, hooked apically (Figs 5 b, 6 b, 8 b, 9 b, 10 e, 11 c, 12 c, 13 c)........................ 2 2. Anal tube appendage curved cephalad in larteral view................................ K. maculata Sohi & Mann, 1992 - Anal tube appendage curved caudad in lateral view (Figs 5 b, 6 b, 8 b, 9 b, 10 e, 11 c, 12 c, 13 c)........................... 3 3. Aedeagus without ventral process near base of shaft (Figs 5 h, 6g, 11 i, 13g)........................................ 4 - Aedeagus with unpaired ventral process near base of shaft (Figs 8 h, 9g, 10 j, 12 i)................................... 7 4. Aedeagal shaft with ventral process near apex (Figs 6 g, 13g)................................................... 5 - Aedeagal shaft without process (Figs 5 h, 11 i)............................................................... 6 5. Paramere forked apically, with apical and basal branch, aedeagal shaft with small thornlike process ventro-apically (Fig. 6 e, g)...................................................................... K. aculeiformis Cao & Zhang sp. nov. - Paramere bifurcated apically, with dorsal and ventral branch, aedeagal shaft with large serrated protrusion ventro-medially (Fig. 13 e, g)................................................................ K. serrata Cao & Zhang sp. nov. 6. Apex of paramere straight, aedeagal shaft expanded in lateral view (Fig. 11 f, i)......... K. imminuta Yang & Zhang sp. nov. - Apex of paramere sinuate, aedeagal shaft not expanded in lateral view (Figs 5 e, f, h).......... K. alba Dworakowska, 1981 7. Ventral process not extended to midlength of aedeagal shaft (Figs 8 h, 9g)......................................... 8 - Ventral process surpassing midlength of aedeagal shaft (Figs 10 j, 12 i)........................................... 10 8. Paramere footlike apically, heel expanded, ventral processes of aedeagus rounded in lateral view (Fig. 9 e, g)...................................................................................... K. explanata Cao & Zhang sp. nov. - Paramere with second extension apically, ventral processes of aedeagus pointed in lateral view (Fig. 8 h, i)............... 9 9. Aedeagal shaft expanded in lateral view, almost straight............................... K. minuta Dworakowska, 1994 - Aedeagal shaft not expanded in lateral view, obviously curved ventrad (Fig. 8 h)........... K. brevis Cao & Zhang sp. nov. 10. Ventral process of aedeagus with broadened and concave apex in caudal view....... K. borealis Dworakowska & Sohi, 1978 - Ventral process of aedeagus pointed apically in caudal view (Figs 10 k, 12 j)....................................... 11 11. Paramere forked apically (Fig. 10 h).............................................. K. furcata Cao & Zhang sp. nov. - Paramere not forked apically (Fig. 12 g)................................................................... 12 12. Aedeagus with base of ventral process broader than that of shaft in lateral view (Fig. 12 i).................................................................................................. K. megaprocessa Cao & Zhang sp. nov. - Aedeagus with base of ventral process slightly narrower than that of shaft in lateral view......................................................................................... K. simlensis Dworakowska, Nagaich & Singh, 1978Published as part of Yang, Meixia, Cao, Yanghui & Zhang, Yalin, 2013, Taxonomic study of the genus Kapsa Dworakowska with a new subgenus, and new combinations and records for Tautoneura Anufriev (Hemiptera: Cicadellidae: Typhlocybinae: Erythroneurini), pp. 117-142 in Zootaxa 3630 (1) on page 128, DOI: 10.11646/zootaxa.3630.1.4, http://zenodo.org/record/22287
Phortica FLOCCIPES CAO & CHEN 2009, SP. NOV.
No full textPHORTICA FLOCCIPES CAO & CHEN SP. NOV. (FIGS 1, 8, 13–15) Material examined: Holotype male, CHINA: Dajiuhu, Shennongjia, Hubei, 3.viii.2005, H. W. Chen (SCAU, No. 120020). Paratypes: CHINA: four males, three females, same data as holotype except 3–5.viii.2005, H. Z. Cao, H. W. Chen, and M. F. Xu (one male and one female in KIZ; the rest in SCAU, Nos 120021–25); two males, two females, Miyaluo, Lixian, Sichuan, 8–10.ix.2005, M. F. Xu and H. L. Cao (SCAU, Nos 120026–29). Description: Male and female. Head: frons black, with grey pollinosity. Thorax: scutum almost black, with grey pollinose pattern. Scutellum black, with a pair of yellow patches submedially. Legs: hind tibiae with three black rings, three irregular rows of suberect setae on ventral surface, which are slightly shorter than tibia width (Fig. 2A), apically with one long curved seta (Fig. 2B). All fourth and fifth tarsomeres black, the rest grey-yellow. Male terminalia: cercus with two strong setae (Fig. 14). Surstylus medially protrudent, with two rows of about seven to eight prensisetae, apically round, with four prensisetae (Fig. 14). Paramere submedially with three small processes, two of them with sensillum, apically with one sensillum; basal process with fine sawteeth (Fig. 15). A KEY TO SPECIES OF THE PHORTICA HANI SPECIES COMPLEX (MALES) 1. Arista with only short dorsal branches; wing R 4+5 and M 1 veins nearly parallel; fifth sternite notched posteromedially; cercus ventrally with two to three long, strong setae; paramere with one spike-like process basally; aedeagus nearly membranous (Phortica hani complex)..........................................................................................2 2. Hindleg tibia lacking a long seta apically (males only known); surstylus with one prensiseta apically; basal spike-like process of paramere lacking fine sawteeth............................................................................... 3 – Hindleg tibia with a long seta apically; surstylus apically with two prensisetae at least; basal process of paramere with fine sawteeth.............................................................................................................................4 3. Surstylus apically truncate; cercus ventrally with three long setae......................................................................................................................................................... Phortica longicauda Cao & Chen sp. nov. – Surstylus apically pointed; cercus ventrally with two long setae......... Phortica longiseta Cao & Chen sp. nov. 4. Hindleg tibia apically with one row of short, scopiform setae on ventral surfaces (male only known); surstylus with two prensisetae apically.................................................................. Phortica panda Cao & Chen sp. nov. – Hindleg tibia lacking scopiform setae apically; surstylus with three prensisetae at least................................5 5. Hindleg tibiae with three black rings and two to three rows of suberect setae on ventral surface, lacking long setae on posteroventral surface; surstylus not covered by epandrium..................................................................6 – Hindleg tibiae with two rings, lacking fringe-like setae on ventral surface, with one row of long setae on posteroventral surface, surstylus covered by epandrium........................................................................... 7 6. Fringe-like setae of hindleg tibiae as long as 1.5¥ of tibia width; surstylus medially not protrudent, with two prensisetae.................................................................................................. Phortica hani (Zhang & Shi) – Fringe-like setae of hindleg tibiae shorter than tibia width; surstylus medially protrudent, with seven to eight prensisetae arranged in two rows.................................................. Phortica floccipes Cao & Chen sp. nov. 7. Scutellum orange-brown, black along margin; hindleg tibia basally to apically with one row of about 11 long setae on anteroventral surface which are about as long as the tibia width......................................................................................................................................................... Phortica hirtotibia Cao & Chen sp. nov. – Scutellum entirety blackish; hind tibiae distally with one row of about eight strong setae on anteroventral surface, most of which are shorter than the tibia width............................. Phortica pinguiseta Cao & Chen sp. nov. A KEY TO PHORTICA HANI SPECIES COMPLEX BASED ON ND2 AND COI SEQUENCES In the following key to seven species of the P. hani complex, character statuses at diagnostic sites were compared between a given pair of taxa. Each status depiction starts with a letter denoting its affiliated gene (N: ND2; C: COI), followed by a number (in subscript) indicating the site positions in the sequences of the affiliated gene, and then by the codon position of the site (in parentheses and in subscript), the nucleotide type (after a colon), and the corresponding amino acid type (after a slash, all shown by standard three-letter abbreviations). No character was found to diagnose between P. floccipes and P. panda based on their ND2 or COI sequences. 1. N 330 (3rd): A/Leu; N 627 (3rd): A/Leu; N 919 (1st): A/Met; C 204 (3rd): A/Val; C 534 (3rd): T/Arg; C 574 (1st): C/Leu; C 627 (3rd): T/Thr; C 705 (3rd): T/Phe; C819 (3rd):T/Tyr; C 894 (3rd): C/Asp; C1002 (3rd): A/Pro................................................................................2 – N330 (3rd): T/Phe; N627 (3rd): T/Phe; N919 (1st): G/Val; C204 (3rd): T/Val; C534 (3rd): A/Arg; C574 (1st): T/Leu; C627 (3rd): A/Thr; C705 (3rd): C/Phe; C819 (3rd): C/Tyr; C 894 (3rd): T/Asp; C1002 (3rd): G/Pro.............................................................................. 4 2. N292 (1st): G/Val; N605 (2nd): C/Thr; N996 (3rd): A/Met; C72 (3rd): C/Ala; C279 (3rd): T/Pro; C402 (3rd): C/Ile; C573 (3rd): T/Phe; C756 (3rd): T/Ile; C805 (1st): C/Leu; C1083 (3rd): C/Val; C1201 (1st): T/Leu; C1335 (3rd): T/Tyr........................................................................................................................................................... Phortica longiseta Cao & Chen sp. nov. – N 292 (1st): A/Met; N 605 (2nd): T/Ile; N 996 (3rd): T/Ile; C 72 (3rd): T/Ala; C 279 (3rd): C/Pro; C 402 (3rd): T/Ile; C 573 (3rd): C/Phe; C 756 (3rd): C/Ile; C805 (1st): T/Leu; C1083 (3rd): T/Val; C1201 (1st): C/Leu; C1335 (3rd): C/Tyr................................................................... 3 3. N144 (3rd): C/Asn; N333 (3rd): T/His; C1023 (3rd): A/Gly; C1089 (3rd): T/Ile........... Phortica pinguiseta Cao & Chen sp. nov. – N144 (3rd): T/Asn; N333 (3rd): C/His; C1023 (3rd): G/Gly; C1089 (3rd): C/Ile............ Phortica hirtotibia Cao & Chen sp. nov. 4. N441 (3rd): A/Lys; N444 (3rd): T/Pro; N795 (3rd): A/Gln; N810 (3rd): C/Asn; C201 (3rd): A/Met; C456 (3rd): T/Gly; C474 (3rd): A/Gly; C537 (3rd): A/Met; C 648 (3rd): C/Ser; C 747 (3rd): T/Phe............................................................................................................................................... Phortica floccipes Cao & Chen sp. nov. / Phortica panda Cao & Chen sp. nov. – N 441 (3rd): G/Lys; N 444 (3rd): C/Pro; N 795 (3rd): G/Gln; N 810 (3rd): T/Asn; C 201 (3rd): G/Met; C 456 (3rd): A/Gly; C 474 (3rd): G/Gly; C 537 (3rd): G/Met; C648 (3rd): T/Ser; C747 (3rd): C/Phe.....................................................................................................5 5. N405 (3rd): C/Ile; N 603 (3rd): C/Phe; N651 (3rd): C/Thr; N774 (3rd): T/Pro; N915 (3rd): T/Asn; C513 (3rd): C/Ala; C594 (3rd): T/Pro; C855 (3rd): G/Val; C1218 (3rd): A/Lys.................................................................................... Phortica hani (Zhang & Shi) – N405 (3rd): T/Ile; N 603 (3rd): T/Phe; N651 (3rd): T/Thr; N774 (3rd): A/Pro; N915 (3rd): C/Asn; C513 (3rd): T/Ala; C594 (3rd): G/Pro; C855 (3rd): T/Val; C 1218 (3rd): G/Lys............................................................... Phortica longicauda Cao & Chen sp. nov. Measurements: BL = 3.70 mm in holotype (range in four male and five female paratypes: 3.50–4.20); ThL = 1.75 mm (1.60–2.00); WL = 3.30 mm (3.05– 3.60); WW = 1.35 mm (1.30–1.75). Indices: arb = 3/0 (3–6/0), adf = 0.79 (0.53–0.79), flw = 1.64 (1.54–2.00), FW/HW = 0.50 (0.49–0.53), ch/o = 0.13 (0.12–0.14), prorb = 1.21 (1.00–1.33), rcorb = 0.52 (0.38–0.53), vb = 0.36 (0.32–0.59), dcl = 0.52 (0.49– 0.62), presctl = 0.44 (0.44–0.57), sctl = 1.05 (1.03– 1.07), sterno = 0.81 (0.65–0.94), orbito = 1.70 (1.46–1.67), dcp = 0.26 (0.19–0.30), sctlp = 0.87 (0.72– 0.96), C = 2.54 (2.57–3.24), 4c = 1.37 (1.07–1.26), 4v = 2.50 (2.25–2.65), 5x = 0.88 (0.68–1.10), ac = 2.25 (1.69–2.08), M = 0.65 (0.49–0.76), C3F = 0.56 (0.43– 0.60). Etymology: A combination of the Latin words floccus and pes, referring to the hindleg tibia with suberect setae. Distribution: China (Hubei, Sichuan). A KEY TO SPECIES OF THE PHORTICA HANI SPECIES COMPLEX (MALES) 1. Arista with only short dorsal branches; wing R 4+5 and M 1 veins nearly parallel; fifth sternite notched posteromedially; cercus ventrally with two to three long, strong setae; paramere with one spike-like process basally; aedeagus nearly membranous (Phortica hani complex)..........................................................................................2 2. Hindleg tibia lacking a long seta apically (males only known); surstylus with one prensiseta apically; basal spike-like process of paramere lacking fine sawteeth............................................................................... 3 – Hindleg tibia with a long seta apically; surstylus apically with two prensisetae at least; basal process of paramere with fine sawteeth.............................................................................................................................4 3. Surstylus apically truncate; cercus ventrally with three long setae......................................................................................................................................................... Phortica longicauda Cao & Chen sp. nov. – Surstylus apically pointed; cercus ventrally with two long setae......... Phortica longiseta Cao & Chen sp. nov. 4. Hindleg tibia apically with one row of short, scopiform setae on ventral surfaces (male only known); surstylus with two prensisetae apically.................................................................. Phortica panda Cao & Chen sp. nov. – Hindleg tibia lacking scopiform setae apically; surstylus with three prensisetae at least................................5 5. Hindleg tibiae with three black rings and two to three rows of suberect setae on ventral surface, lacking long setae on posteroventral surface; surstylus not covered by epandrium..................................................................6 – Hindleg tibiae with two rings, lacking fringe-like setae on ventral surface, with one row of long setae on posteroventral surface, surstylus covered by epandrium........................................................................... 7 6. Fringe-like setae of hindleg tibiae as long as 1.5¥ of tibia width; surstylus medially not protrudent, with two prensisetae.................................................................................................. Phortica hani (Zhang & Shi) – Fringe-like setae of hindleg tibiae shorter than tibia width; surstylus medially protrudent, with seven to eight prensisetae arranged in two rows.................................................. Phortica floccipes Cao & Chen sp. nov. 7. Scutellum orange-brown, black along margin; hindleg tibia basally to apically with one row of about 11 long setae on anteroventral surface which are about as long as the tibia width......................................................................................................................................................... Phortica hirtotibia Cao & Chen sp. nov. – Scutellum entirety blackish; hind tibiae distally with one row of about eight strong setae on anteroventral surface, most of which are shorter than the tibia width............................. Phortica pinguiseta Cao & Chen sp. nov.Published as part of He, Xiaofang, Gao, Jianjun, Cao, Huazhi, Zhang, Xiaolei & Chen, Hongwei, 2009, Taxonomy and molecular phylogeny of the Phortica hani species complex (Diptera: Drosophilidae), pp. 359-372 in Zoological Journal of the Linnean Society 157 (2) on pages 362-364, DOI: 10.1111/j.1096-3642.2009.00516.x, http://zenodo.org/record/468781
Experimental study of phase equilibria in the systems PbO x -CaO and PbO x -CaO-SiO2
No full textThe reported experimental work on the systems PbO-CaO and PbO-CaO-SiO in air is part of a wider research program that combines experimental and thermodynamic computer modeling techniques to characterize zinc/lead industrial slags. Extensive experimental investigation by high-temperature equilibration and quenching techniques followed by electron probe microanalysis was carried out in the temperature range 640 °C to 1500 °C (913 to 1773 K) and in the composition ranges 0 to 65 mol pet SiO and 0 to 42 mol pet CaO. Liquidus and solidus data were reported for most of the primary phase fields. Liquidus surfaces in the systems CaO-Pb-O and PbO-CaO-SiO in air were completely reconstructed. Extensive solid solutions of PbO in α' dicalcium silicate and CaPbSiO, were measured
Classical Bioglass® and innovative CaO-rich bioglass powders processed by Spark Plasma Sintering: A comparative study
No full textDensification and crystallization phenomena taking place when a recently developed CaO-rich bioactive glass and conventional 45S5 Bioglass® are processed by Spark Plasma Sintering (SPS) are examined. Fully dense and wholly amorphous products can be obtained from the new glass composition at 730 ◦ C after 2min dwell time. Moreover, temperatures equal or higher than 830◦C are needed to induce crystal- lization (- and -CaSiO3) in the parent glass. Conversely, Na6Ca3Si6O18 crystals are formed in sintered 45S5 samples produced under optimal conditions (550◦C, 2min), although the glassy character is still preserved.
Products resulting from the innovative glass powders generally display higher hardness and local elastic modulus. Devitrification also provides improvements in this system. In contrast, mechanical properties become slightly worsen when classical bioglass is processed at 600 ◦ C. This can be probably associated to the corresponding decrease in compactness which, apparently, overcomes the benefits arising from the crystallization progress
SiO2 Promoted CaO Diffusion to C Phase at 1500 and 1700 °C
No full textTo better understand the mass transfer behaviors in CaC2 production from CaO and coke, this paper studies the diffusion behaviors of CaO and graphite, with or without ash, at 1500 and 1700 °C. CaO and graphite are pressed into tablets and heated alone or in close contact. Physical and chemical changes in these tablets are analyzed by XRD and SEM+EDX. In some experiments, thin Mo wires are placed between the closely contacted CaO and graphite tablets to identify the diffusion direction. It is found that the diffusion between CaO and low-ash graphite is very limited. SiO2 in a high-ash graphite diffuses into CaO tablet and reacts with CaO to form Ca2SiO4, which then diffuses into the graphite tablet easily and leads to CaC2 formation at 1700 °C
- …
