Spent hydrogenation catalysts are important secondary resources due to richness in the valuable metals of Ni,Mo and *** of valuable metals from spent catalysts has high economic value and environmental benefits since ...
详细信息
Spent hydrogenation catalysts are important secondary resources due to richness in the valuable metals of Ni,Mo and *** of valuable metals from spent catalysts has high economic value and environmental benefits since they are hazardous wastes as *** recycling processes including hydrometallurgical leaching and soda roasting-leaching have disadvantages such as generating large amounts of wastewater,long process,and low recovery efficiency of valuable ***,this paper proposed synergistic enrichment of Ni,Mo and V via pyrometallurgical reduction at 1400-1500℃.The melting temperature and viscosity of slag were reduced through slag designing by software FactSage *** phase diagram of Al_(2)O_(3)-Cap-SiO_(2)-Na_(2)O-B_(2)O_(3)was drawn,and low-temperature region(≤1300℃)was selected as target slag ***,Mo,and V can be collaborative captured and recovered through the mutual solubility at molten *** the melting temperature and the amount of CaO,Na_(2)O and C were conducive to improving the metals recovery *** kilogram-scale experiments were carried out,and the recovery efficiencies of Ni,Mo and V were 98.3%,95.3%and 97.9%under optimized conditions:at 1500℃,with the basicity of 1.0,13.1 wt%SiO_(2),7.0 wt%B_(2)O_(3),7.7 wt%Na_(2)O and 20.0wt%*** distribution behavior of valuable metals was clarified by investigating the melting process of slag and the reduction in valuable *** was preferentially reduced and acted as a capturing agent,which captured other metals to form NiMoV alloys.
Most known catalytic dehydration of sugar alcohols such as D-sorbitol and D-mannitol can only produce di-dehydrated forms as major product,but monodehydrated products are also useful ***,both di-and mono-dehydration d...
详细信息
Most known catalytic dehydration of sugar alcohols such as D-sorbitol and D-mannitol can only produce di-dehydrated forms as major product,but monodehydrated products are also useful ***,both di-and mono-dehydration demand a high temperature(150℃ or higher),which deserves further *** improve the mono-dehydration efficiency,a series of metal-containing hydrothermal carbonaceous materials(HTC)are prepared as catalyst in this *** reveals that the composition of preparative solution has a key influence on the morphology of *** transformation of D-sorbitol,all HTC catalysts show low conversions in water regardless of temperature,but much better outputs are obtained in ethanol,especially at a higher *** D-mannitol is selected as substrate,moderate to high conversions are obtained in both water and *** the other hand,high mono-dehydration selectivity is obtained for both sugar alcohols by using all *** origin of mono-dehydration selectivity and role of carbon component in catalysis are discussed in association with *** study provides an efficient,mild,eco-friendly,and cost-effective system for mono-dehydration of sugar alcohols,which means a lot to development in new detergents or other fine chemicals.
The effect of Mg/Si mass ratio on the microstructure and mechanical properties of Al-Mg-Si cast aluminum alloys under sub-rapid solidification conditions was *** study utilized four different Mg/Si ratios:2.83,1.91,1....
详细信息
The effect of Mg/Si mass ratio on the microstructure and mechanical properties of Al-Mg-Si cast aluminum alloys under sub-rapid solidification conditions was *** study utilized four different Mg/Si ratios:2.83,1.91,1.73,and *** analyze the evolution of the microstructure,particularly the second phase,various techniques were employed:optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and electron backscatter diffraction(EBSD).Additionally,thermodynamic calculations were performed using the Thermal-calc software to further understand the microstructural *** show that as the Mg/Si ratio decreases from 2.83 to 1.53,α-Al grains become more uniformly ***,the morphology of the Mg_(2)Si phases changes from skeletal to short stick shapes with a decreasing aspect *** as-cast Al-Mg-Si alloy with a Mg/Si ratio of 1.53 exhibits high strength,achieving an ultimate tensile strength(UTS)of 320.6 MPa and a yield strength(YS)of 249.9 *** cast alloy with a Mg/Si ratio of 2.83exhibits the highest elongation,reaching 5.31%.This superior elongation is attributed to the uniform distribution of Mg_(2)Si phases,which possess a long skeletal ***,the alloy with a Mg/Si ratio of 1.53 demonstrates the lowest elongation,primarily due to the central concentration of Mg_(2)Si phases,which are characterized by their short stick shapes.
Retting has been employed to extract natural fibers from agricultural wastes as a biological and cost-effective approach for *** its global abundance,banana pseudo-stem is a promising agro-waste for lignocellulosic fi...
详细信息
Retting has been employed to extract natural fibers from agricultural wastes as a biological and cost-effective approach for *** its global abundance,banana pseudo-stem is a promising agro-waste for lignocellulosic fiber *** this study,fibers were extracted from the pseudo-stems after being pre-treated under four conditions using seawater at room temperature for up to 35 d Bacterial isolation from the fresh seawater sample and screening for ligninolytic ability were *** load as well as laccase and manganese peroxidase enzyme activity profile assay during the retting duration were *** transform infrared(FT-IR)and X-day diffraction(XRD)analyses were also examined for both pre-treated and untreated extracted *** results shows that six out of the eight bacterial isolates had the ability to degrade *** treatments(Raw stem+Raw seawater)and(Autoclaved stem+Raw seawater)recorded the highest viable bacterial load of 9.24×102 and 4.46×102 CFU,respectively,on the 14th day of the retting ***,the highest laccase and manganese peroxidase enzymes activity was recorded for(Raw stem+Raw seawater)and(Autoclaved stem+Raw seawater)treatments in the second to the third *** FT-IR spectra of the pre-treated fibers revealed relative reductions in peaks attributed to polysaccharides and other amorphous substances for all retting *** XRD diffractogram revealed that the crystallinity index(CI)of pre-treated fibers increased in all seawater retting treatment ***,the CI for fibers pre-treated under enzymatic conditions were enhanced even after five *** analysis for selected bacterial isolates showed homology to sequences of Bacillus velezensis,Shewanella sp.L8–5,and Citrobacter amalonaticus and Bacillus subtilis j8 *** these findings,it was suggested that physical,biological,and chemical actions were collectively involved in the seawater retting process of banana ps
To widen the applications, cationic cellulose beads were synthesized by adding glycidyltrimethylammonium chloride (GTAC) to cellulose fibers dissolved in a mixture of tetraethylammonium hydroxide and urea at room temp...
详细信息
The present study aims at identifying the critical Reynolds number for transition from laminar to turbulent in irregular shaped mini-channels. Numerical study including conjugate heat transfer and axial conduction is ...
详细信息
The electricity demand is increasing rapidly with the development of society and ***-fired thermal power plants have become one of the primary sources of electricity generation for ***,coal-fired thermal power plants ...
详细信息
The electricity demand is increasing rapidly with the development of society and ***-fired thermal power plants have become one of the primary sources of electricity generation for ***,coal-fired thermal power plants produce a great amount of by-product coal fly ash every *** fly ash disposal in landfills requires a sizable space and has negative environmental ***,it is crucial to develop new technologies and methods to utilize this enormous volume of solid waste in order to protect the *** this review,the fundamental physical and chemical character-istics of coal fly ash are introduced,and afterward the disposal policies and utilization ways of coal fly ash are discussed to gain a comprehensive understanding of the various ways this *** leaching of valuable metals in coal fly ash and the extraction of metal elements in leachate under different conditions are also ***,the possibility of coal fly ash to serve as a supplementary source for mineral resources is analyzed,providing a basis for its extensive use as a raw material in the metal industry in China and worldwide.
暂无评论