An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
The ‘plainification of materials’ has been conceptualized to promote the sustainable development of materials. This perspective, for the first time in the field of biomaterials, proposes and defines ‘plain metallic biomaterials (PMBs)’ with demonstrated research and application case studies of pure titanium with high strength and toughness, and biodegradable, fine-grained and high-purity magnesium. Then, after discussing the features, benefits and opportunities of PMBs, the challenges are analyzed from both technical and regulatory aspects. Regulatory perspectives on PMB-based medical devices are also provided for the benefit of future research, development and commercialization.
In order to take the advantage of the large reaction surface of fine iron ore concentrates and expect a high reaction rate without sticking or agglomeration problems, a suspension gas-solid reaction system was designed to explore the feasibility of fast direct reduction of fine iron ore. In this study, upward gas flow was used to prolong the particles' falling time. Pure silica particles were chosen as the dispersion agent. The Stokes gas-particle model with the relaxation time concept was applied to accurately model the falling process. Highly metallized porous iron particles over 90% of Rd (reduction degree) were obtained at 1273 K with 20.1 s of hydrogen reduction. The morphology evolution characteristics of the fine particles during reduction were investigated via SEM, and a conceptual diagram was formulated in this paper in order to well understand the relationship between the reduction condition and the structural evolution. The shrinking core model was introduced to analyzing the reduction kinetics in this experiment system, which indicates that the microstructure evolution of the particle during reduction can be influenced by temperature and the resistance of internal mass transfer cannot be ignored under this experiment condition especially in the later stage of reduction.
TiC ceramics, a kind of ultra-high temperature ceramics, are primarily prepared by the synthesized TiC powders from high purity metallic titanium or titania. In this work, a novel method for sustainable utilization of hot Ti-bearing blast furnace slag to prepare TiC ceramics was developed. Firstly, the Ti was efficiently transformed into the TiC in hot Ti-bearing blast furnace slag through carbothermal reduction. The high-purity TiC powders were fully recovered from molten carbonized Ti-bearing slag through supergravity separation, where the mass fraction and recovery ratio of Ti in TiC powders were up to 77.89 wt.% and 95.58 %. The TiC ceramics with a relative density of 98.23 % were prepared from the recovered TiC powders via spark plasma sintering method, which possess the favourable mechanical properties including Vickers hardness (Hv) of 23.3 ± 0.4 GPa, fracture toughness (K IC) of 3.96 ± 0.24 MPa m1/2 and flexural strength of 371.9 ± 15.4 MPa.
Based on the precipitation experiment results of titanium bearing molten slag during cooling liquation, perovskite (CaTiO3) was the first precipitated phase, and 1593–1563 K was the advantageous precipitation temperature of perovskite from the molten simulated slag with a basicity of 1.30. So if perovskite could be separated from the slag melt at this temperature range, at which perovskite becomes a solid state while other minerals form into the molten slag, it would be beneficial for the solid-liquid separation between them. Hence, selective separation experiments of perovskite from titanium bearing slag melt with a basicity of 1.30 at 1578 K by super gravity were carried out in this study, and the results confirmed that it was an effective method. In this process, the molten slag moved along the super gravity direction and went through the filter and then concentrated as the slag phase in the bottom crucible, in which it was practically impossible to find any perovskite grains. In contrast, all the perovskite grains were intercepted by the filter and concentrated as the perovskite phase on the filter, which appeared as the typical dendrite structure. Consequently, after super gravity separation with gravity coefficient of G = 660 to G = 840 at 1578 K for 10 minutes, the mass fraction of TiO2 in the perovskite phase was up to 46.36 wt%, whereas that of the slag phase was only 8.77 wt%. In this case, the recovery ratio of Ti in the perovskite phase was up to 78.17%.
The industrial RE‐bearing (rare‐earth‐bearing) slag has a considerable concentration of rare‐earth elements (REEs), so the recovery of REEs resources from these systems has attracted widespread attention. However, the basic data of RE phases is seriously lacked and divergent, which greatly limits the efficient utilization. In this study, in situ separation of RE phases from RE‐bearing slag systems was conducted via super gravity, and the high‐purity crystals of calcium cerite (CaO: 13.53 wt.%, SiO 2 : 26.02 wt.%, Ce 2 O 3 : 65.45 wt.%) and cefluosil (CaO: 14.67 wt.%, SiO 2 : 22.14 wt.%, CaF 2 : 2.64 wt.%, Ce 2 O 3 : 67.23 wt.%) were selectively separated from the CaO–SiO 2 –Ce 2 O 3 and CaO–SiO 2 –CaF 2 –Ce 2 O 3 systems with the high REEs recovery percentages of 96.10% and 98.23%, respectively. Based on the characterization of high‐purity calcium cerite and cefluosil crystals, the chemical formula, crystal structure, and Rietveld refinement were characterized, and the data has been assigned the deposition numbers of 2130965 and 2142394 in CCDC database. This study supplements the lack of basic data of RE crystals and provides theoretical reference and guidance for the utilization of RE‐bearing slag systems.
As an environmentally hazardous waste, electric arc furnace (EAF) dust had a potential to provide a wider resource of potassium if recycled due to high potassium content. In this study, the chemical and mineralogical characteristics of the EAF dust, especially the existing state of potassium, were analyzed. The results showed that the dust consisted dominantly of manganese oxides (Mn3O4, MnO, MnO2) and manganese silicate (MnSiO3). The K element existed in the dust was in the form of potassium permanganate (K2Mn4O8, insoluble) and potassium sulfate/sulfite (soluble). Then the soluble potassium salts in the dust were recovered by water leaching and crystallization. The recovery ratio of K reached 88.2%, and the products K2SO4 and KCl with the K2O content of 65.25% were obtained. During leaching, the Mn3+ and Mn4+ components were reduced to Mn2+ by sulfide (S2−) or sulfite (SO32−), and the S2− and SO32− components were oxidized to SO42−. The leaching kinetics was studied by the specific electrical conductivity method. The apparent activation energy was 7.76±0.65 kJ/mol, suggesting that the rate controlling step of leaching process was the diffusion of K+ through the diffusion layer.
A 3D model applying temperature- and carbon concentration- dependent material properties was developed to describe the scrap melting behavior and carbon di
An innovative approach of super gravity was proposed to separate fine Al2O3 inclusions from liquid steel in this study. To investigate the removal behavior
Boron-bearing slag is a typical secondary resource of boron (B) and magnesium (Mg). However, the boron dispersed in the amorphous phase, which is difficult to recover from the boron-bearing slag. This study investigated the effect of supergravity field on the competitive crystallization behavior of B, Si, and Mg in boron-bearing slag, and developed an efficient method for two-stage separation of olivine (Mg2SiO4) and suanite (Mg2B2O5) from the slag. In stage 1, the M g 2 + was preferentially crystallized into olivine with the S i O 4 4 - rather than B 2 O 5 4 - at 1623 K to 1473 K, and the olivine crystals were efficiently separated from the boron-bearing slag melt under the supergravity field. Due to the separation of olivine in the stage 1, the S i O 4 4 - was depleted and a favorable condition for single crystallization of suanite was created in the remaining boron-rich slag. Thus in stage 2, the B 2 O 5 4 - and M g 2 + were adequately crystallized into suanite at 1473 K to 1323 K, and the suanite crystals were recovered further from the separated boron-rich slag melt in the supergravity field. Moreover, the high purity and high crystallinity of the suanite and olivine separated from the boron-bearing slag confirmed the enhancement of supergravity field on the solid-liquidseparation in a complex slag system.
Due to the oolitic structure of the high phosphorus iron ore and the closely wrapping of apatite and hematite phases, an approach using jet mill was utiliz
At present, the utilization of vanadium slag suffers from underutilization of Ti resources and the generation of large quantities of toxic tailings. Therefore, there is an urgent need for a green and sustainable process to achieve the recovery of V and Ti from vanadium slag. In this study, the crystallization mechanism of V and Ti in vanadium slag with basicity and temperature was revealed. The results indicated that V in vanadium slag with a basicity of 1.6 was enriched primarily to Fe2VO4 at 1500-1400 °C, whereas Ti was mainly crystallized into CaTiO3 at 1400-1200 °C. On this basis, above 90.22 % of V and 87.89 % of Ti were firstly recovered into Fe2VO4 and Ti-enriched slag via super-gravity at 1400 °C, respectively. After that, over 81.04 % of Ti was further recovered into CaTiO3 from the Ti-enriched slag via super-gravity at 1200 °C. Following two separations, the high-purity Fe2VO4 with up to 40.56 wt% V2O3 and CaTiO3 with up to 54.42 wt% TiO2 were obtained, which could be used for the preparation of FeV alloy and Ti pigments. The tailings with a FeO content exceeding 39.93 wt% could be further used to recover Fe. This method simultaneously extracts V and Ti resources from vanadium slag, avoids the generation of toxic tailings at source, and can combine with the current V metallurgy process, realizing the comprehensive utilization of vanadium slag in a green and sustainable way.
B-bearing blast furnace slagB-bearing blast furnace slag is a typical secondary resource of boronBoron enrichment (B), which is produced from the ludwigite ore in ironmaking process. However, B is dispersed in the amorphous phase resulted to inefficiently recover...
A method of manufacturing aluminum foams by super gravity and its effects on the products were investigated. Three-dimensional (3-D) open-cell aluminum foams with pore sizes of 4.5, 3.5, 2.0, and 0.5mm were successfully prepared by infiltration casting with gravity coefficients (G) of 300–900. Increasing the gravity coefficient could effectively overcome the surface tension of molten aluminum infiltrating into the channels of precursor, thus significantly enhancing the product performances of aluminum foams.
Massive hazardous Cr-bearing steel slag is produced from the electric furnace smelting process of stainless steel, while the soluble poisonous hexavalent chromium (Cr(VI)) seriously limits the sustainable utilization of the slag. In this study, a novel method of selective solidification and super-gravity separation was proposed to recover Cr resources from Cr-bearing steel slag safely and efficiently. Firstly, Cr elements were selectively solidified into Cr-spinel in Cr-bearing steel slag with wt.%(MgO) = 6.00, and the high-purity Cr-spinel crystals ((Mg0.43Fe0.28Mn0.29)(Cr1.67Al0.33)O4) were effectively recovered from the molten slag via super-gravity separation with a significant Cr2O3 content of 58.08 wt% and a high Cr recovery rate of 88.58 %. On this basis, the chemical formulas and crystal structures of various high-purity Cr-spinel crystals were characterized and the solidification mechanism of Cr in Cr-spinel was determined, to verify that Cr3+ was accordingly substituted by Al3+ when Fe2+ and Mn2+ were substituted by Mg2+, and Cr elements were efficiently solidified and recovered into the Cr-spinel in stable trivalent chromium (Cr(III)) based on the XPS results. Thus the effective leaching amount of Cr in Cr-spinel was as low as 0.011 mg/L, which provided a basis for sustainable utilization of Cr-bearing steel slag.
The super-gravity technique was used to remove the SiO2 composite inclusions from 304 stainless steel. The effects of different super-gravity coefficients and super-gravity treatment time on the removal effect of inclusions were studied. It was found that the SiO2-based composite inclusions floated up to the top of the sample after the super-gravity treatment, and the inclusions in the lower part of the sample were largely removed. The volume fraction and number density of inclusions presented a gradient distribution along the direction of the super-gravity, which became steeper with increasing gravity coefficient and treatment time. The total oxygen content at the bottom of the sample was reduced from 150 ppm to 93 ppm within 15 min of super-gravity treatment under the gravity coefficient of G = 80.
A new approach to enrich MFe and RO phase from the converter slag by super gravity was investigated. The samples obtained by the gravity coefficient G=600 and cooling rate V=5K/min from 1623K to 1373K appeared significant stratification and the MFe gathered at the...
