Ratio Of CaO Research Articles

Clean and efficient lithium recovery from waste electrolytes via an environmentally short process

Low-cost and environmentally friendly recycling methods can incorporate strategic elements from discarded lithium-containing aluminum electrolytes (LiAE), which is crucial for alleviating resource shortages and environmental footprint. This study aims to develop a method for the comprehensive utilization of LiAE through low-temperature leaching of calcification. Unlike traditional high-temperature acidification roasting/ transformation processes (320–850 °C), the calcification leaching method only involves one-step leaching and avoids high heat energy consumption. Besides, this low-temperature calcification method chemically destroys the crystal structure of metal fluorides (Li, Na, K, etc.), ensuring a high leaching rate while ensuring an alkaline environment for lithium extraction from the leaching solution without additional alkaline neutralization. The lithium extraction rate exceeds 96 %, with high-purity Li2CO3 and NaOH prepared. The CaCO3 produced by decalcification has the potential for recycling (in the form of CaO after calcination). Meanwhile, the effects of operating temperature, mass ratio of CaO to LiAE, liquid–solid ratio, and leaching time on the calcium leaching reaction were systematically studied. The economic benefits and creative evaluation of the process were evaluated. Finally, the regenerated LCO prepared from recycled Li2CO3 has been proven to have good electrochemical performance compared to commercial LCO, demonstrating the feasibility of energy storage application. In summary, the comprehensive utilization of LiAE by the calcium leaching method has been proven to be feasible.

Experimental study on parameters optimisation of adding vanadium-titanium magnetite to iron ore pellet

Vanadium-titanium magnetite has coarse particle size, small specific surface area, poor surface hydrophilicity and low strength when being made into pellets. However, vanadium-titanium magnetite pellet also has a certain application requirement due to its large reserves and high comprehensive utilisation value. Therefore, this article investigated the effects of water ratio, bentonite ratio, vanadium-titanium magnetite ratio, CaO ratio and roasting temperature on the strength of pellets. The results showed that better parameters of green pellets were obtained as follows: the water ratio was 9%, the bentonite ratio was 2.5% and the vanadium-titanium magnetite ratio was 25%. There was no obvious relationship between the CaO ratio and green pellet strength. Better preparation parameters of roasted pellets were as follows: water ratio was 9%, bentonite ratio 2%, vanadium-titanium magnetite ratio 25%, CaO ratio 1% and roasting temperature 1300°C. This provides guidance for the effective use of vanadium-titanium magnetite.

Ca2.68Fe10.32Si1.00O20 - a strongly disordered SFCA-related phase in the system CaO-Fe2O3-SiO2

As part of a systematic investigation into the ternary system CaO-Fe2O3-SiO2, we discovered a phase with a general chemical composition of A14O20 (where A represents Ca, Fe, and Si) and previously unknown symmetry. Synthesis experiments were conducted at 1200 °C in air with an oxide ratio of CaO:Fe2O3:SiO2 = 3:5:1 in the starting mixture. In addition to β-Ca2SiO4, and hematite (Fe2O3), powder X-ray diffraction analysis indicated the presence of compounds related to the aluminum-free counterpart of a silico-ferrite of calcium and aluminum (SFCA), one of the major bonding phases in iron ore sinter. Single crystals of this so-called SFC phase, large enough for diffraction experiments, were found in the sintered pellet fragments under a digital microscope. The compound with composition Ca2.68Fe10.32Si1.00O20 crystallizes in space group I2/c and has the following basic crystallographic data: a = 10.4643(10) Å, b = 15.2740(11) Å, c = 5.3050(5) Å, β = 110.017(9)°, V = 796.69(13) Å3 and Z = 2. The final composition, as determined by crystal structure refinement, differs slightly from the weight-specified starting mixture of Ca3Fe10SiO20 and suggests the presence of both Fe(III) and small amounts of Fe(II) in the sample. The crystal structure is related to that of the triclinic polytype-1A of SFC, but exhibits a higher degree of disorder due to the partial occupation of additional octahedrally and tetrahedrally coordinated sites. This results in a smaller unit cell and an increased space-group symmetry. The described phase can be regarded as a basic or family structure, from which the two simplest polytypes (1A and hypothetical 2M) can be derived through ordering processes of cations among different possible vacancies. The chemical similarity to one of the phases of the SFCA-family suggests that such disordered compounds could also occur in industrial sinters.

Molecular dynamics study on structural characteristics of amorphous C‐S‐H with different Ca/Si ratios

AbstractAs the major hydration product of cement, hydrated calcium silicate (C‐S‐H) governs the overall performance of cement‐based materials. The molar ratio of CaO to SiO2 (Ca/Si ratio) significantly affects the structure and properties of C‐S‐H. This study analyzed the effect of Ca/Si ratios (0.83–2.0) on the structural morphology evolution, bond lengths and angles, polymerization process, and nanoporosity of amorphous C‐S‐H, with the help of the ReaxFF force field. The results showed that the reacted C‐S‐H tend to form a fibrous network‐like morphology at low Ca/Si ratios, while the silicate chains are prone to accumulating at high Ca/Si ratios, forming a dense granular ovoid structure. Meanwhile, the Ca/Si ratio has no effect on the bond lengths and angles. In addition, the Ca2+ ions can interrupt the silicate chains during hydration, which leads to a decrease in the average silicate chain length with increasing Ca/Si ratio. The porosity of C‐S‐H decreases from 59.3% to 54.3% when the Ca/Si ratio increases from 0.83 to 2.0. It can be deduced from these findings that the increase in the Ca/Si ratio decreases the compressive strength of cement‐based materials but increases their durability.

Enhanced self-cementation of arsenic-contaminated soil via activation of non-thermal plasma-irradiated ferromanganese: A mechanistic investigation

The self-cementation characteristics of arsenic (As)-contaminated soil were comprehensively investigated in this study. Different non-thermal plasma-irradiated binary (hydro)oxides of polyvalent ferromanganese (poly-Fe-Mn) were synthesized and exploratorily dispersed to soil samples to activate solidification and stabilization during the self-cemented process. The maximum compressive strength of 56.35 MPa and the lowest leaching toxicity of 0.004 mg/L were obtained in the proof test under optimal conditions (i.e., the mass ratio of the poly-Fe-Mn to the soil sample of 0.05; the mass ratio of the composite alkali activator (NaOH + CaO) to the soil sample of 0.25; the mass ratio of CaO to NaOH of 1.5; the mass ratio of the DI water to the binder of 0.515). The composite alkaline activator primarily contributed to the strength formation of the self-cemented matrix while the poly-Fe-Mn significantly influenced the reduction of the As-leaching toxicities. The poly-Fe-Mn maintained diffusion-controlled polycondensation and strengthened the nucleation process during self-cementation. The amount of water and the dosage of poly-Fe-Mn caused an interactive influence on the self-cemented solidification of contaminated soils. The solidified samples with poly-Fe-Mn exhibited better thermal decomposition than their counterparts, reflecting the enhancement of poly-Fe-Mn to the matrix. Some minerals including C-S-H, kaolinite, gehlenite, diopside sodian, augite, and albite were matched in the samples, directly demonstrating the geopolymerization-steered self-cementation of the As soil. The employment of poly-Fe-Mn not only reinforced the immobilization of As pollutants in the matrix but also induced the self-cementation of soils by intensifying the composite alkaline-activated geopolymerization kinetics.

Effect of alumina on formation mechanism and structure characteristic of sodium calcium silicate compounds with different stoichiometric coefficients

In order to illustrate the effects of Al2O3 on silicate structure for synthesizing sodium calcium silicate compounds, the formation characteristics, lattice parameters, molecular structure and element chemical state of sodium calcium silicates with different Al2O3 proportions through solid-state reaction were investigated using XRD, SEM-EDS, Raman spectroscopy and XPS analyses. Increasing the Al2O3 content facilitates the formation of Na2CaSiO4 and converts the polymorph of Na2Ca6Si4O15 from γ-type into β-type. The product particles aggregate to form clumps by increasing the Al2O3 content when the molar ratios of Na2O and CaO to SiO2 are 0.5 and 1.5, and the network orderliness of silicates deteriorates to form glassy phase at the low CaO and Na2O contents. Al2O3 can engage in the bonding process with silicate crystals to produce a finite solid solution. Increasing the Al2O3 porportion is advantageous for facilitating the participation of [AlO6] in the Si-O-Al bonding reaction, which leads to the depolymerization of [Si2O7]6-, [Si3O10]8- and [Si6O18]12− and promotes the formation of silicate chains of [SiO4]4- and [Si2O7]6-. Moreover, increasing the contents of Na2O and CaO promote the formation of [AlO4] and the depolymerization within silicate chains, which increases the bonding number of Si-Oter and Al-Oter and then reduces the binding energies of Si2p and Al2p orbits.

Alkaline activation via in-situ caustification of one-part binders of composite precursors of waste glass and limestone

Mixtures of powders of waste glass (WG), limestone (LS), Na2CO3 and CaO were used to formulate novel one-part in situ alkali-activated cement (WG-AAC). The in-situ interaction Na2CO3-CaO-H2O promoted the formation of CaCO3 and NaOH, which promoted the WG and LS dissolution and influenced the micro- and molecular features of the resulting cementitious products. Pastes and mortars developed 1-year strengths of up to 29 MPa and were stable underwater. Characterization by XRD, SEM, EDS, and 29Si-NMR indicated that a Na2CO3:CaO ratio close to 1:1 resulted in polymerized C-S-H, CaCO3, silica gel, and Ca-modified silica gel, which were intimately intermixed and possibly crosslinked through Q3 bonds. Such phases interacted synergistically improving the underwater stability of the WG-AAC, indicating that in-situ caustification is a suitable and practical alkaline activation for SiO2-rich precursors.

Thermodynamic analysis on the coupling effects of operating parameters in sorption-enhanced chemical looping gasification with rice husk as feedstock

Sorption-enhanced chemical looping gasification (SECLG) has a favorable ability to produce H2-rich syngas without any extra separation process. To comprehensively investigate the performances, the temperature in the fuel reactor (FR) side TFR, molar ratio of steam or CaO to carbon (λsteam/C, λCaO/C), circulation ratio of oxygen carrier to carbon (λOC/C) are changed to test their effects on the products. Then the coupling effects on SECLG are deeply analyzed by changing two and three of the operating parameters. Results demonstrate that under fundamental conditions, the sorption enhancement becomes unavailable when the temperature is higher than 775 °C but decreasing λsteam/C and increasing λOC/C can elevate this critical temperature. Increasing the λOC/C or λsteam/C can enhance the H2 concentration first, then weaken H2 concentration. The maximum value of H2 concentration is 62.47% when λOC/C = 0.4 and λsteam/C = 1.9. When the FR temperature is lower than 775 °C, there is an optimal λOC/C for maximizing the H2 concentration at a specific temperature. When the temperature is 650 °C, λOC/C = 0.5 and λsteam/C = 1.9, the maximum value of H2 concentration can reach 95.73% in SECLG.

Comparative Study of the Structural, Microstructural, and Mechanical Properties of Geopolymer Pastes Obtained from Ready-to-Use Metakaolin-Quicklime Powders and Classic Geopolymers.

This study compares the structural, microstructural, thermal, and mechanical properties of geopolymer pastes (GPs) created through traditional methods and those derived from ready-to-use powders for geopolymer (RUPG) materials. The metakaolin (MK) precursor was activated using a sodium silicate solution or CaO and MOH (where M is Na or K). Various ratios of precursor/activator and Na2SiO3 or CaO/MOH were tested to determine the optimal combination. For RUPG, the MK precursor was activated by replacing the sodium silicate solution with quicklime. Metakaolin, alkaline hydroxide, and quicklime powders were mixed at different CaO ratios (wt%) and subjected to extensive ball milling to produce RUPG. The RUPG was then hydrated, molded, and cured at 20 °C and 50% relative humidity until testing. Analytical methods were used to characterize the raw and synthesized materials. Classic geopolymers (CGPs) activated with quicklime burst after one hour of molding. The results indicated slight amorphization of GP compared to raw MK, as confirmed by X-ray diffraction analysis, showing N(K)-A-S-H in CGP and N(K)-A-S-H with calcium silicate hydrate (C-S-H/C-A-S-H) in RUPG. The compressive strength of MK-based geopolymers reached 31.45 MPa and 34.92 MPa for GP and CGP, respectively, after 28 days of curing.

Preparation and characterization of low-activity coal bottom ash-based cementitious materials via orthogonal experiment

The effective use of coal bottom ash produced by burning coal can reduce the pollution of solid waste to land and water resources. Meanwhile, the use of coal bottom ash as cementitious materials can reduce the demand for traditional resources and carbon emissions, availing to promoting the sustainable development of the construction industry. However, the application and popularization of coal bottom ash-based cementitious materials are facing many practical problems. For example, the utilization rate of coal bottom ash is low, and the traditional alkali activation method has some limitations such as high cost and poor safety. For this reason, through orthogonal experiment and range analysis, new calcium combination activators were explored for the preparation and optimization of coal bottom ash-based cementitious materials. The coal bottom ash-based cementitious materials with compressive strength up to 17 MPa was prepared, when the mass ratio of CaO: Ca(OH)2: AlPO4 was 1: 0.15: 0.10 : 0.05 and preparation temperature was 15 °C. Furthermore, the influence of various factors on the compressive strength of the products was evaluated comprehensively: AlPO4 > CaO and Ca(OH)2 > preparation temperature. The action effect and reaction mechanism of various factors were revealed by means of fluidity test, setting time test, XRD, FTIR and SEM-EDS. The results show that calcium combination activators react with coal bottom ash to mainly form C-A-S-H gel. Among the calcium combination activators, CaO greatly improves the rate of early hydration reaction, Ca(OH)2 is conducive to the sustained and stable development of late hydration reaction, and AlPO4 can improve the fluidity and setting time of the slurry. Moreover, although the water and environment temperature show the weakest influence in the laboratory stage, the influence of this factor on the property of the cementitious materials in the actual project cannot be ignored. This research has important scientific and engineering significance for promoting coal bottom ash-based cementitious materials in economic development and environmental protection.

Effect of CaO/Fe2O3 Ratio and Oil/Methanol Molar Ratio on Biodiesel Production from Waste Cooking Oil

Biodiesel is a renewable liquid fuel that can be produced through the transesterification reaction of biomass. The objective of this research was to examine the effect of comparative composition of CaO and Fe2O3 on CaO/Fe2O3 catalysts from eggshells and Fe2O3 in the production of biodiesel from waste cooking oil. In addition, it was also studied the effect of the ratio of oil and methanol on the yield and characteristics of the biodiesel produced. Catalysts were prepared through impregnation. The esterification-transesterification process was carried out with the conditions WCO:methanol molar ratio of 1:3, 1:6, 1:9, 1:12 and 1:15, catalyst (3%wt oil), heated at 65°C for 3 hours with a stirring scale of 1200 rpm. The results showed biodiesel production using CaO: Fe2O3 catalyst with the ratio of CaO: Fe2O3 70:30 and WCO:methanol molar ratio of 1:9 obtained higher yield (84.5%) compared to others. The best biodiesel yield produced is the CaO:Fe2O3 catalyst ratio of 70:30 and the WCO:methanol molar ratio of 1:9 with a biodiesel yield of 84.50% with a methyl ester content of 99.63% and a FAME yield of 84.14%. The biodiesel produced has met the requirements of the Indonesian National Standard (SNI) in terms of density and viscosity.

Multifunctional CaO template promotes the synthesis of natural N-doped hierarchical porous carbon for supercapacitors

N-doped porous carbon with reasonable pore size distribution is conducive to improving low specific capacitance and low ion transport efficiency. Natural N-doped hierarchical porous carbon (NNHPC) was synthesized by microwave-assisted heating using kapok tree and chlorella vulgaris as raw materials. CaO was used as a template to extend the pore channels and simultaneously enhance the retention of N atoms in NNHPC. The pyrolysis properties of the samples and surface functional groups of NNHPC were analyzed, revealing that CaO enhanced the creation of nitrogenous compounds in the coke by inhibiting protein nitrogen decomposition. It led to a 74.45 % increase in N atom retention. When the addition ratio of CaO to biomass is 1:10, the optimal sample NNHPC-1CaO exhibits the highest specific surface area (SSA) of 3117.73 m2/g, accompanied by a microporous volume of 0.71 cm3/g. Therefore, NNHPC-1CaO exhibits the highest specific capacitance of 429.18 F/g, which still achieves excellent rate performance with 69.53 % at 20 A/g. The symmetric supercapacitor achieves a best energy density of 11.01 Wh/kg at 125 W/kg.

Research of Reactions on Ferronickel Laterite by Rotary Kiln Furnace Process

Nickel is an important strategic metal, which is mainly used for the production of a wide range in the production of various anti-corrosion steels. Electric furnace, rotary kiln and smelting is currently the world-wide integration process for the production of ferronickel from nickel laterite ore, despite its high energy consumption. In this study, with the aim of providing some meaningful analysis for the production of ferronickel and reactions formed in the rotary kiln. The samples obtained were analyzed under conditions including reducing parameters (temperature and time) and smelting parameters (CaO, Al2O3 and MgO ratios). The metal content as well as the Ni, Fe, S and P content of ferronickel were taken into account. The results showed that Ni-containing ferronickel from a laterite with 0.88 wt. % Ni during the process in the rotating furnace is characterized by different reactions which have been verified by XRD diffraction.

Inclusion Removal Process of Homogeneous CuCr50 Alloy In-Situ Synthesized by Al-Mg Composite Strengthening Reduction Coupling Slagging.

To overcome the problem of Cr2O3 and Al2O3 inclusions in CuCr50 alloy prepared by aluminothermic reduction method, in this paper, a novel methodology for strengthening metal-slag separation through in situ slagging is proposed. CuCr50 alloys were prepared by metallothermic reduction using Al and Al-Mg as reducing agents, and the physical properties of the slag, such as viscosity, density, and surface tension, were adjusted by controlling the proportion of CaO in the slagging agent in the raw material to achieve good separation of the slag-metal. The results show that with the ratio of CaO increased, CaO and MgO were coupled to make slag, which combined with Cr2O3 and Al2O3 to form CaCr2O4, MgCr2O4, and CaAl4O7 in the slag, thus reducing the content of impurities in the alloy. When RCaO/(CaO + Al2O3 + MgO) = 20%, the Cr content ranged from 46.61% to 47.09%, the inclusions accounted for 1.60%, the Cr particle size was refined to 20 µm, the number of Cr spherical crystals accounted for 9.88%, the conductivity reached 14.96 MS/m, and the hardness reached 100.23 HB. After heat treatment, the Cr phase was refined in the alloy, the conductivity increased from 14.96 MS/m to 18.27 MS/m, and the hardness increased from 100.23 HB to 103.1 HB. This method is expected to provide an effective method for the preparation of CuCr50 contact materials.

Catalytic upgrading of Naomaohu coal pyrolysis volatiles over CaO catalyst

Catalytic upgrading of coal pyrolysis volatiles is one the promising way to achieve high quality tar and gas. In this study, catalytic upgrading of volatiles from Naomaohu (NMH) coal pyrolysis has been conducted in a two-stage fixed bed reactor using CaO as catalyst. The aim of this work was to investigate the catalytic effect of CaO on the gas and liquid product distribution, as well as the variations in gas and coal tar components. Simulated distillation and GC-MS analysis has been used to understand the distribution of tar component. On the one hand, CaO exhibits selective cleavage of large molecules, such as long-chain esters, leading to the production of aromatics through the processes of dehydrocyclization and aromatization. CaO has the ability to stabilize free radicals that are generated during the cleavage of large molecules, thereby promoting the formation of light aromatic hydrocarbons. Consequently, the light tar fraction (boiling point <360 °C) increased from 64.4 % to 74.6 %, while the heavy tar fraction (boiling point＞360 °C) decreased from 35.6 % to 25.4 % in the pyrolysis tar. The compounds with long ester chains in the tar composition decreased by 24.4 %. The content of light components, such as benzenes, naphthalene, and phenols, increased significantly with the increasing catalytic temperature. Specifically, the content of benzenes, naphthalene, and phenols increased by 11.83 %, 17.73 %, and 4.41 % respectively at the coal to CaO ratio of 1/0.5 and the catalytic temperature of 600 °C. On the other hand, the CaO absorbs the CO2 pyrolysis gas leading to an elevation in the concentration of CH4 and H2 in the pyrolysis gas. The concentration of CO2 decreased from 37.9 % to 16.58 % compared to without the catalyst while the concentrations of H2 and CH4 increased to 26.24 % and 31.15 % at the catalytic temperature of 450 °C. The CO2 absorption ratio reached a maximum value of 97.16 % at a coal to CaO ratio of 1/2. These findings suggest that the CaO catalyst beneficial both for improving the tar and gas quality.

Distribution Behavior of Impurities during the Hydrogen Reduction Ironmaking Process

The traditional blast furnace ironmaking process is the most widely used ironmaking process globally, yet it is associated with significant drawbacks, including high energy consumption and carbon emissions. To achieve low-carbon ironmaking, researchers have developed hydrogen ironmaking, which is capable of achieving lower CO2 emissions. Nevertheless, the distribution behavior of impurities has been less studied in the existing research on hydrogen ironmaking. Therefore, in this study, the factors affecting the slag properties and distribution of impurity elements during hydrogen ironmaking were investigated using FactSage, and smelting experiments were carried out. The results show that temperature has the greatest influence on the distribution behavior of the impurities, and excessively elevated temperatures result in the ingress of a significant quantity of impurities into the reduced iron. Reduced iron with a purity of 98.52% was obtained under the conditions of 10%, 10%, 2%, and 2% ratios of CaO, SiO2, MgO, and Al2O3, respectively, a hydrogen flow rate of 12 mL/min, and a temperature of 1400 °C; Lg L Mg, Lg L Al, Lg L Si, and Lg L Ca were 2.72, 2.41, 3.36, and 2.45, respectively (“L” stands for slag-to-metal ratio). The slag was mainly dominated by the silicate, and the iron was mainly lost in the form of mechanical inclusions in the slag. This study will enrich the basic theory of hydrogen ironmaking and is of great significance for the realization of carbon neutralization.

Geochemical and thermodynamic constraints on the genesis of coexisting alkaline and tholeiitic basalts from Datong, North China: Implication for compositional diversity of continental intraplate basalts

Continental intraplate basalts usually exhibit diverse compositions varying from silica-deficient alkaline basalts to silica-excess tholeiites. However, the mechanism of compositional diversity remains controversial. Here, we conducted comprehensive petrology, mineral chemistry, whole-rock geochemistry, and Sr–Nd–Hf isotopic compositions, as well as thermodynamic modeling for the coexisting Datong alkaline and tholeiitic basalts, North China, to put constraints on the source characteristics and melting conditions of these basalts. The alkaline basalts and tholeiites have contrasting major elemental and Sr–Nd–Hf isotopic compositions (87Sr/86Sr, 0.703431–0.703603 vs. 0.703912–0.704010; ƐNd, 5.5–7.0 vs. 2.9–4.8; ƐHf, 9.5–10.6 vs. 8.2–9.6) and trace-element patterns. The observed compositional differences could be explained by neither magmatic processes (e.g., assimilation and/or fractional crystallization), varying melting degrees due to lithospheric thickness variations, nor the melt-peridotite interaction. Instead, lithological heterogeneous mantle sources containing different types of pyroxenite should be considered to account for the compositional diversity, as indicated by olivine (high Ni, Zn/Fe, and low Mn/Zn) and whole-rock chemistry (low CaO, high Fe/Mn, FC3MS, and FCKANTMS ratios). The incompatible trace element-based thermodynamic modeling was carried out to put quantitative constraints on the mantle source characteristics and melting conditions. The modeling results suggest that the source of alkaline basalts contains 30% silica-deficient pyroxenite +70% lherzolite with melting pressure and temperatures of 2 GPa, 1370 °C, whereas the tholeiites have 15% silica-excess pyroxenite +85% harzburgite in the source with melting conditions of 1.5 GPa, 1425 °C. The estimations, together with the thermobarometric calculations using major-element compositions, suggest that the tholeiitic and alkaline basalts were generated by melting of lithological heterogeneous mantle sources under lithosphere with different thicknesses. The lithological heterogeneity originated from recycled components from historical peripheral subducted plates, and melting of such lithological heterogeneity is likely related to asthenosphere upwelling and convection induced by the deeply subducted Pacific slab. Our study emphasizes the fundamental role of source lithological heterogeneity in the generation of co-existing Datong alkaline and tholeiitic basalts and may provide insights into the origin of compositional diversity of other continental intraplate basalts.

Influence of chemical composition and discontinuities on energy transformation and rock mass behaviour: Insights into geological dynamic

AbstractIn this study, efforts were made to incorporate the influence of discontinuities and failure modes of rock into the classification of rock masses. The past tectonic activities may create microfractures in the rock body therefore the failure moods have been determined carefully under uniaxial compression. The results of the discontinuity analysis, conducted through kinematic study, highlighted the significant impact of wedge failure on the failure of the rock mass. In correlating the geological strength index with rock mass rating, it was observed that joint volume played a negative role, whereas compressive strength played a positive role. These correlations are particularly applicable for a certain rock type, as the compressive strength is inherently dependent on the type of rock. The analysis of failure modes under uniaxial compression reveals that the dissipation energy coefficient initially undergoes rapid increase before reaching its minimum value at the failure stage. The microstructures of the rock effect significantly the elastic and dissipation energy characteristics. Specifically, the axial splitting failure mode emerges as predominant. Given the area's past tectonic activity, these results emphasize the impact of microfractures within the rock body. Relating the failure criteria with the chemical composition of rock types reveals that rocks abundant in SiO2, such as gabbronorite, tend to exhibit brittle failure. Additionally, a dominance of Al2O3 over Fe2O3 suggests a predisposition towards brittle failure, while an increased ratio of CaO to MgO implies increased susceptibility to compression.

Catalytic co-pyrolysis of coal and polypropylene plastic into liquid fuel

The decline in fossil fuel sources has stimulated research in the field of renewable fuels. Efforts are currently being made to find alternative energy sources that have high efficiency and are environmentally friendly. By looking at the existing problems, research on the co-pyrolysis of coal and polypropylene (PP) plastic into liquid fuel is interesting to do. The co-pyrolysis process was carried out at 400oC and nitrogen gas was flowed with a flow rate of 100 mL/min for 60 minutes with various ratio of raw material coal/PP plastic (100/0, 75/25, 50/50, 25/75), and ratio of CaO catalyst/raw material (0%, 10%, 15%, 20% w/w). The results showed that with the reduction in the ratio of coal/plastic, the yield of liquid fuel increased. Co-pyrolysis of coal: PP plastic with a ratio of 25:75 with the addition of 20% CaO catalyst obtained 37.56% liquid fuel yield with the characteristics of density of 0.839 g/mL, viscosity of 2.51 cSt, calorific value of 46.813 MJ/kg and pH of 2.9.

Petrogenesis and geodynamic implications of the Late Devonian dioritic and granitic intrusive rocks in the Dananhu Belt, Eastern Tianshan Orogenic Belt

The Late Devonian magmatism of the Dananhu arc belt in the Central Asian Orogenic Belt provides a critical geological record. This study provides new comprehensive geochronological, geochemical, and Sr–Nd isotopic data of granodioritic and dioritic intrusions in the Dananhu belt. These findings contribute to unraveling the regional tectonic history and constraining the geodynamic processes involved. Zircon U–Pb dating indicates that the granodiorites and diorites were formed at 382.7 ± 3.8Ma and 363.1 ± 4.3Ma, respectively. The granodiorites show characteristics similar to I-type granites with high SiO2, low MgO and Mg# and aluminium saturation index (<1.1), negligible Eu anomalies, low (K2O + Na2O)/CaO ratios and zircon saturation temperatures (average = 696 °C). Granodiorites also show depleted isotope signatures (εNd(t) = +5.85 to +6.27 and low (87Sr/86Sr)i = 0.704082–0.704583) and juvenile TDM ages (741–793Ma), indicating their origin from a juvenile crust. The diorites are characterized by enrichments in large ion lithophile elements, U and Pb, but depleted in Nb and Ta displaying typical geochemical features of a subduction-related origin, together with high εNd(t) (+6.10 to +6.84) and low initial Sr isotopes (0.703745–0.704601), suggesting that they originated from a subduction fluid modified depleted mantle. The petrogenesis of both granodiorites and diorites in the Dananhu arc provides evidence that they formed through magmatic processes in a subduction tectonic setting. Considering the adakites associated with slab melting from previous studies in the Dananhu arc, it is plausible that the north-dipping subduction of the North Tianshan oceanic lithosphere have contributed to the Dananhu arc magmatism during the Late Devonian.