aosha Li

A Novel Conversion of Ti-Bearing Blast-Furnace Slag into Water Splitting Photocatalyst with Visible-Light-Response

A novel visible-light-response photocatalyst was prepared through the heat treatment of Ti-bearing blast-furnace slag with sodium nitrate and subsequently leaching processes in which most of the SiO2, Al2O3, and MgO in Ti-slag (TS) have been separated. The photocatalytic activity of the TTS was studied by observing the evolution of H2 under the UV–Vis and visible light. Compared with the TS and commercial perovskite CaTiO3, the sample prepared exhibited an exclusive visible-light-response activity and enhanced H2 evolution.

Infrared Emissivity of La0.8Sr0.2MnO3 with Three Different Structures

La0.8Sr0.2MnO3 samples with rhombohedral, orthohombic and monoclinic structures were prepared by solid state reaction, sol-gel and co-precipitation methods, respectively. Lattice parameters, grain size, morphology, infrared absorption and emissivity of samples were investigated. The results indicated that the average crystallite size calculated from XRD result and particle size of orthohombic sample were smaller than those of the other two samples, and honeycomb shape grains were observed in orthohombic sample. Due to lower crystal symmetry, Mn-O stretching vibration peaks of the three samples shifted to higher infrared wavenumber. According to the theory of wave optics and Kirchhoff law, bigger rhombohedral sample showed higher emissivity than monoclinic one. However, due to the honeycomb structure of orthohombic sample, repeated reflection and scattering led to the increase of absorption, and orthohombic sample exhibited the highest emissivity.

Polymerization behavior of silicic acid with Fe3+, Al3+, and Ca2+ coexisting ions

Silicic acid was prepared by acid hydrolysis of water-quenched calcium silicate, and Ca2+, Al3+, and Fe3+ were added to investigate the polymerization behavior. Effect order of the three ions on the polymerization was Fe3+ > Al3+ > Ca2+. Due to decreased polymerization rate caused by Fe3+ at pH < 3, average diameter of the colloidal particles at pH = 2 was larger than that at pH = 3. New infrared absorption peaks were found at 2360 cm−1 which may be attributed to Ca–OH, Al–O–Si, and Fe–O–Si, respectively, and it was especially obvious for Fe3+. For three ions coexisting system, the new peak showed a slight shift to 2370 cm−1. Preventing ability of Fe3+ on water binding is much stronger than promoting ability of Al3+. Dehydration process of bound water was hindered by adding the three ions, and due to higher bound water content, endothermic peak for Al3+ system was stronger. Crystallization process was hindered by Ca2+ and Fe3+.Graphical abstract

Utilization of Air Quenched Steel Slag in Decorative Ceramics with Higher Mechanical Properties

Air quenched steel slag is much more difficult to utilize than other kinds of steel slag. 50 % percent of air quenched steel slag was used to prepare brown decorative ceramics. Due to the broken (SiO4)n glass network, the optimum sintering temperature decreases with increasing Na2O and MgO, respectively. The major crystalline phase of the samples is diopside (CaMgSi2O6) with minor anorthite phase (CaAl2Si2O8). Due to remelted glass phase, the X-ray diffraction intensity of the samples decreases with increasing Na2O, while the intensity increases with increasing MgO which is beneficial to crystallization of the samples. The bending strength of the samples decreases with increasing Na2O (from 155.3+/-2.49 MPa to 143.1+/-2.01 MPa), while the strength increases with increasing MgO (from 147.4+/-3.44 MPa to 169.4+/-4.04 MPa). The Vickers hardness of the samples shows similar trends with the bending strength. The samples exhibit much better mechanical properties than marble, granite, tile and other similar ceramics reported, and present good chemical resistance. Therefore, The ceramics based on air quenched steel slag may have great potential for applications as building decorative materials, and it provides a promising way for the utilization of air quenched steel slag. Introduction Steel slag is a kind of intractable industrial waste, which is produced as a byproduct from either the conversion of iron to steel in basic oxygen furnace, or the melting of scrap in electric arc furnace. The chemical composition of steel slag is highly variable depending on the raw materials and production process, and the utilization of steel slag is difficult [1,2]. According to different cooling methods, air cooled steel slag, water quenched steel slag, water sprayed steel slag, air quenched steel slag, etc. are obtained respectively during the cooling process of molten slag. Since air quenched steel slag is very hard, and much more difficult to be ground than air cooled, water quenched or water sprayed steel slag, the utilization of air quenched steel slag is more difficult [3]. So far, there have been no effective ways for largely utilization of air quenched steel slag. Air quenched steel slag contains calcium oxide, silicon dioxide, magnesium oxide and so on, which are the important component of glass ceramics. In recent years, coal combustion ash [4,5], blast furnace slag [6,7], fly ash and filter dusts from waste incinerators [8-10], mud from metal hydrometallurgy [11,12], different types of sludge [13,14] and other industrial wastes [15,16] have been used for the preparation of glass ceramics. Khater [17] has reported that glass ceramics based on 56.78 % blast furnace slag were prepared by mixing quartz sand, dolomite, limestone and clay as other batch constituents. The glass ceramics obtained from vitrified sewage sludge have been studied by Bernardo and Dal Maschio [18], and the sample features good mechanical properties and a 3rd Annual International Conference on Advanced Material Engineering (AME 2017) Copyright

Co-precipitation behaviour of titanium-containing silicate solution

The co-precipitation behaviour of a simulated Al2(SO4)3-TiOSO4-Na2SiO3 solution that imitated the lixivium of Ti-bearing blast furnace slag (Ti-slag) leached by sulphuric acid was investigated in this study. Various chemical analyses were employed to study the selective precipitation of multiple target components. Based on the high-added-value applications of Ti-slag, a new method was developed to prepare aluminium titanate composites from titanium-containing silicates. The findings demonstrate that the onsets of Ti and Al precipitation occur at pH values of 3.5 and 5.0, respectively, followed by Si precipitation. The particle sizes of the co-precipitates were greatly influenced by the precipitants, pH and the initial Al/Ti mole ratio. The results also show that the precipitation ratio of Ti, Al and Si generally increases with the pH and temperature, regardless of the Al/Ti mole ratio. The Si-O-Al, Ti-O-Al, and Ti-O-Si bonds that were formed were dependent on the pH and the initial Al/Ti mole ratio. There was a synthesis path for β-Al2TiO5 (AT) from the solid-state reaction between rutile and α-Al2O3 at 1362.5°C. The AT composites were successfully prepared by sintering the co-precipitates at 1450°C, which exhibited good thermal stability as estimated by the XRD measurements of the sample annealed at 1200°C for 4 hours.

Existence of a solid solution between 3CaO · V2O5 and 3CaO · P2O5

In the present work, a solid solution of 3CaO · V2O5 and 3CaO·P2O5 was found below 1573 K. The solution could be described as 3CaO+xV2O5+(1−x) P2O5. The solid solutions at three compositions, namely, X=1/3, X=1/2, and X=2/3, were synthesized. X-ray diffraction (XRD) patterns revealed that the crystals exhibited a rhombohedra structure. X-ray indexes at these compositions were reported.