Advanced Materials Research Vol. 402

Abstract: A strain of Acidithiobacillus ferrooxidans designated S t1 was isolated and identified from the acid mine drainage of Tianmashan Coal Mine, Tongling county, Anhui province. Its morphological, physiological and biochemical characters, growth conditions of pH value and temperature, 16S rDNA sequence and the phylogenetic tree was studied. Results showed that the bacteria strains from different sites have divergence at the curve of pH and Eh values during the enriching culture. The isolated strain S t1 grew in a pH rang from 2.0 to 3.0 and temperature 25 to 35°C with over 98％similarity to Acidithiobacillus ferrooxidans in 16S rDNA sequence.

Abstract: ηA kinetic study of the leaching of stone coal ore with sulfuric acid has been investigated. The effects of the stirring speed, particle sizes of stone coal, acid concentration, leaching temperature and acid-ore ratio on the leaching rate of vanadium were examined. It was found that the leaching rate of vanadium was significantly influenced by leaching temperature. The shrinking core model was applied to the leaching process and the results showed that the process was based on chemical reaction control. And the rate of reaction was expressed as 1-(1-η)^1⁄3=4.98×10⁶·e^-55488⁄RT·t. The apparent activation energy for the leaching of vanadium⁄ was calculated to be ¾5⁄5.49 kJ/mol using Arrhenius expression.

Abstract: Redissolution of cemented cobalt from zinc sulphate solution occurs, and is a well known problem among zinc producers. A variety of mechanism of cobalt redisisolution have been proposed in the literatures, however, it is still not very well understood. The influencing factors of cobalt redissolution such as detention time, oxidation, particle size of zinc dust and copper ion have been investigated in this paper. The redissolution does not occur when very large particles are used but the redissolution of cobalt is significant from small zinc particles. The redissolution is obvious with copper ion added, while the redissolution is not occurred from the zinc sulphated solution without copper ion added. The redissolution mechanism of cobalt is obtained.

Abstract: The oxidation kinetics of copper or aluminum added with magnesium was investigated by a modified Chou model. The effect of the addition of magnesium in copper or aluminum was discussed. The calculation results showed that the activation energy of CuMg0.34 was the highest among Cu-Mg alloys at 600-900 °C, which indicated that it had the best oxidation resistance in all of the samples. The aluminum alloy AA3004 containing 1.0 wt.% Mg showed the better anti-oxide behavior than AA5182 with 4.0 wt.% Mg, and the relation between oxidation rate and oxygen partial pressure could be expressed as 0.71 times power law.

Abstract: According to the reaction shaft operation characteristics during the flash smelting process, 15 groups of slag samples containing high Fe₃O₄ were prepared by some chemical reagents, and then the slag surface tensions were measured using a RTW-10 type synthetic test instrument for melt physical property by means of suspension link. The effects of temperature ( T ), basicity ( B ), the Fe/SiO₂ ratio (m_Fe/m_SiO2), Fe₃O₄ content (ω_Fe3O4), Cu₂O content (ω_Cu2O), MgO content (ω_MgO) and CaO content (ω_CaO) on the slag surface tension (δ) were also studied. Results show that δ fluctuate between 0.3N/m to 0.8 N/m, and is increased with the increase of T, B, m_Fe/m_SiO2, ω_Cu2O, ω_MgO and ω_CaO, and with the decrease of ω_Fe3O4, under the range of slag contents: m_Fe/m_SiO21.36~1.78, ω_Fe3O4 17.83%~21.18%,ω_Cu2O 3.51%~8.34%,ω_MgO 2.21%~6.57%,ω_CaO 6.22%~9.87% and the temperature range of 1380°C to 1500°C. To make the freeze slag adhere to the reaction shaft inner wall easily, the Fe₃O₄ content in freeze slag should be increased and the inner chamber temperature of reaction shaft should be controlled appropriately.

Abstract: The FetO activity calculating model of alkali-containing BF slag was built according to the coexistence theory of slag structure at 1773K. The results reveal: it is correspond to reality and embody the structural characteristics of BF slag. The FetO activity of slag increases obviously with the w(CaO)/w(SiO2) increasing, decreases with the Al2O3 and MgO contents increasing.

Abstract: A novel hydrometallurgical method was developed to recycle valuable metals of Si, Fe and Cu from copper slag. The leaching rates of 98%, 99% and 91% for SiO₂, Fe and Cu, respectively, were obtained under optimized parameters: solid-to-liquid ratio is 1:10; concentration of hydrochloric acid is 35%; the reaction time is 2 hours and at 80-90°C.

Abstract: Facing at the situation that a large amount of BaSO₄/SrSO₄, which seriously impacts on oil production operation scale, has been yielded during oilfield production, three kinds of scale inhibitor (TS-09, TH-60 and PBTCA) were collected from oilfield for comprehensive evaluation. The results show that the three kinds of scale inhibitor have certain scale inhibition effect to BaSO₄/SrSO₄, and the influence of different water quality is obvious. When TH-60 concentration was 100 mg/L, its inhibition rate to BaSO₄ has reached 95%. In comparison, scale inhibition effect of TH-60 to BaSO₄/SrSO₄ is better than the others. TH-60 is more suitable for Huaqing oilfield than TS-09 and PBTCA, concentrations range in 100-180 mg/L especially.

Abstract: The flow state and velocity distribution of liquid metal in the FC-Mold and the influence rules by the magnetic flux density have been investigated when electromagnetic brake adopted, applying mercury as medium to simulate molten steel in the continuous casting process. The velocity measurement has been completed by the Ultrasonic Doppler Velocimeter (UDV) under various magnetic distribution and the influence laws of magnetic flux density on the liquid metal flow in the mold has been analyzed. The experimental results indicate that, when the upper and lower magnetic flux density is 0.18T and 0.5T respectively, a preferable control effect can be obtained, not only the free surface fluctuation can be compressed, but also a plug flow can be rapidly formed.