Advanced Materials Research Vols. 524-527

Abstract: A limonitic laterite ore from Indonesea was treated by pressure leaching in H₂SO₄-Mg(NO₃)₂ medium, using Mg(NO₃)₂ as an oxidant. Experiments were conducted in order to determine the optimum conditions by studying various parameters, including Mg(NO₃)₂/ore mass ratio, initial acidity, reaction temperature, holding time and liquid/solid ratio. Pressure leaching experiments showed that nickel, cobalt and iron extractions were 90.8 %, 91.9 % and 2.1 % after 60 min of leaching at 493 K with 0.06 g/g Mg(NO₃)₂/ore mass ratio, 140 g/L initial acidity and 2 mL/g liquid/solid ratio.The total decrement of acid consumption was 72 g H₂SO₄/kg ore in the presence of Mg(NO₃)₂.

Abstract: In addressing issues related to technology or quality refractory products are among the supporting documents experimental results of the tests. These more or less extensive data sets characterize with some precision observed phenomenon, e.g. some physical or chemical quantity. The role of statistical processing of data from this perspective, the maximum concentration sometimes extremely abundant, but few clear set of experimental data and determine the "seriousness" of this file. When processing data it is to be noted that these characteristics are not fully observed variable, but only a selected part.

Abstract: In order to recover secondary iron-bearing dust, with converter sludge, mill scale, gravitational ash, casthouse ash as raw materials, high basicity carbon composite pellets are prepared to make iron nuggets through self-reduction at high temperature. The study demonstrates that: The effectively separation of iron and slag, naturally pulverization of the slag phase, and good surface quality of bigger, glosser and brighter iron nuggets can be obtained with reduction temperature 1400 °C,C/O molar ratio 1.1,as well as basicity above 1.8 in this process; The iron phase is not generated well and proportion of small size iron nuggets increases when C/O molar ratio is increased; With C/O molar ratio increases or temperature rises, CO generated increases in direct reduction, which strengthen the reducibility atmosphere in the pellets, beneficial to the processing of desulfuration and dephosphorization; Rising temperature accelerates the generation of molten iron, so that, the fixed carbon contacts with the molten iron longer, which increasing the carbon in iron nuggets. More carbon is provided for the carburizing reaction for the sake of increasing C/O molar ratio, as a result of making more carbon in iron nuggets.

Abstract: By means of Oxygen and Nitrogen Analyzer, Metallographic Examination, SLIME, SEM, EDS, etc, the cleanliness of ultra-low carbon steel first slab produced by LD-RH-CC, and the comparative analysis with the cleanliness of normal slab is studied. The results show that T[O] and [N] are obviously decreasing with the increasing of casting length. The micro-inclusions and large-inclusions are generally decreasing with the increasing of casting length. The micro-inclusions of the first slab are mainly from deoxidization products and reoxidation of liquid steel. And the sources of large-sized inclusions mainly are reoxidation of liquid steel, slag entrapment in mould or tundish and stuffing sand. The cleanliness of ultra-low carbon steel first slab is closed to those normal slabs at the length of 3.5m.

Abstract: The separation of niobium and iron from the low grade niobium ore was researched by the technology process of reductive roasting and magnetic separation. Experiments of reductive roasting and magnetic separation were carried out in order to investigate the separation effect at different conditions of roasting temperature and addition amount of coal powders. The results show that the separation of niobium and iron can be realized, meanwhile the niobium can be enriched in the magnetic tailings. The main mineral phase of niobium in magnetic tailings changes into NbC from (Ce,Nd)NbTiO₅ when the roasting temperature exceeds 1150°C. By magnetic separation after roasting with adding 37.5% coal powders at 1050°C, w(T.Fe) of the reduced iron is 86.11%, the percentage metallization is 87.6%, and the yield ratio of iron is 77.4%. Meanwhile, w(Nb₂O₅) of the magnetic tailings is 7.35% which is 2.4 times higher than low grade niobium ore, and the yield ratio of niobium is 98.1%.

Abstract: The second phase particle in steel can refine crystal grain and improve performance of steel products. In the paper, how Sm₂O₃ particle affecting on inclusion and crystal grain size of steel product was studied by adding Sm₂O₃ particle into steel. The result shows the Sm₂O₃ particle will not agglomerate and the content of inclusion in steel will not increase when the particle size is lower than 1.47μm while the content of inclusion will increase obviously when the size is higher than 3.41μm. The Sm₂O₃ particle can combine with sulfide inclusion and deoxided product, which has the same function as adding rare earth alloy into steel partially. So the Sm₂O₃ particle can refine the size of crystal grain of cast structure. The degree of crystal grain was reduced from level 2 to level 4-4.5 and the average size of crystal grain was reduced from 180μm to 90-75μm. And it can also reduce the size of crystal grain of rolled structure. The degree was reduced from level 6.5 to level 11 and it will decrease with increasing of adding content of Sm₂O₃ particle. The best economic and technical norms can be got when the l size of Sm₂O₃ particle is 1.47μm and the adding content is 0.5% of the content of metal.

Abstract: Thermodynamic analysis method for iron and steel manufacturing system is developed to describe the energy flow. The theoretical energy consumption for the manufacturing process is proposed to analyze the energy-saving potential. Energy balance based on enthalpy with a uniform reference state is established to analyze the amounts and forms of energy flow in the manufacturing system. The energy-saving potential of blast furnace system is discussed to choose the appropriate energy-saving methods and technologies.

Abstract: The bioactivity of Cinnamomum cassia bark extract was investigated on eggs, larvae, pupae and adults of Lasioderma serricorne. C. cassia bark extract had potent fumigant toxicity against different developing stages of L. serricorne, and the toxicity increased significantly with the increasing exposure dosage. Larvae and adults of L. serricorne were much more susceptible to the C. cassia bark extract than eggs and pupae. The corrected mortality of eggs, larvae, pupae and adults reached 33.42%, 96.21%, 31.75% and 93.68% at a dosage of 40 µL/L air after 48 h exposure, respectively. The declining order of susceptibility of different development stages of L. serricorne to C. cassia bark extract was as follows: larvae（LD₅₀= 10.12 µL/L air）, adults（LD₅₀= 11.03 µL/L air）, pupae（LD₅₀= 56.46 µL/L air）and eggs（LD₅₀= 92.35 µL/L air）. These results indicate that C. cassia bark extract have huge potential as an alternative to synthetic pesticides for the integrated pest management of L. serricorne in future.

Abstract: To determine reliable molecular thermal maturity parameters for prediction of the physical properties of biodegraded oils, a suite of oils including 11 biodegraded oils from Caoqiao oilfield and 5 non-biodegraded oils from Wangjiagang oilfield in Dongying depression in Bohai-bay basin, eastern of China were analyzed. The oils were selected in a wide range of viscosity in order to investigate the relation between the parameters and oil properties. The data show the effects of biodegradation on some molecular thermal maturity parameters: C₂₉ sterane parameters C₂₉20S/(20S+20R) and C₂₉ββ/(ββ+αα) increased apparently under heavy biodegradation (rank 6~7); parameters C₃₁22S/(22S+22R), C₃₂22S/(22S+22R), C₂₉3-methyl/C₂₉ 4-methyl, (C₂₈+C₂₉Tricyclics)/Ts and (C₂₈+C₂₉Tricyclics)/ (C₂₈+C₂₉Tricyclics +Ts) showed effects from heavy biodegradation (rank 6~7), and terpanes parameters Ts/(Ts+Tm), C₂₉Ts/(C₂₉Ts+C₂₉Tm) and aromatic C₂₀/(C₂₈+C₂₀), (C₂₀+C₂₁)/(C₂₀+C₂₁+C₂₆+C₂₇+C₂₈) and D(_3-6)/(D_3-6+ C₂₉ 4-methylstigmastane 20R showed no effect from heavy biodegradation. Based on the comparison, the molecular maturity parameters C₂₆ to C₂₈ triaromatic parameters C₂₆S/ (C₂₆S+C₂₈S), C₂₇R/(C₂₇R+C₂₈R), C₂₈/(C₂₆+C₂₇+C₂₈) and tricyclic terpanes parameters C₁₉/(C₁₉+C₂₃) were recommended to predict the physical properties of biodegraded oil for these parameters showed no effects from biodegradation(rank 6~7) and better relations with oil physical properties compared to other parameters. Some quantificational equations between these molecular thermal maturity parameters and the physical properties of biodegraded oils were inferred, which may assist in predicting the viscosity and API gravity of reservoired oils before production.

Abstract: Fiber and vessel morphology and the radial variation patterns of fast-growing Toona ciliata were studied in this paper. The results showed that the average of cell length, tangential diameter, double wall thickness, length-width ratio, wall thickness-diameter ratio of fiber were 1038.00μm,17.43μm,4.03μm,34.13,0.25 respectively, which of vessel were 313.61μm,123.63μm,6.18μm,1.36,0.05 respectively. The radial variation patterns vary between different characteristics.