Advanced Materials Research Vols. 616-618

Abstract: Pulp pH value plays a significant role in the froth flotation. Especially in the flotation of fluorite, the performance of flotation will be affected greatly by pulp pH. MO, a new kind of modified fatty acid was used as collector, and H2SO4 and Na2CO3 were used to regulate pulp pH in the experiment. The mechanism of influence of pulp pH on flotation of fluorite and calcite was investigated by such parameters as fluorite recovery, zeta potentials and the infrared spectroscopy about minerals at different pulp pH values. As is shown in the results, the point of zero charge(PZC) of fluorite is pH=9.5 and the PZC of calcite is pH=8.5. The optimum pulp pH of the flotation of fluorite and calcite is determined as 9.5~10 and 8~9 respectively. pH value should be controlled above 9 to depress calcite. Finally, 9.5~10 was determined as the optimum pH to float the fluorite from the calcium-containing fluorite ores.

Abstract: In this paper, The Copper-bearing minerals Powder (≤2mm) in Dahongshan is used in conical ball grinding, the experimental study shows that the effect of ball material ratio on the grinding efficiency is obvious. The critical value and the optimal value range of the ball material ratio are different on different grinding stages, the feasible ball material ratio of coarse grinding is bigger than the one of fine grinding. In the test conditions, in terms of the ball material ratio, the critical value of ores’ over crushing in coarse grinding is 13, and the optimal range is 6-8, which is beneficial to the next beneficiation; while the critical value in fine grinding is 7 and the optimal range is 5-7. Although the ball material ratios are different, the change rule of grinding fineness corresponding to different particle size fractions is consistent, which can be used as a reference in the site operation optimization.

Abstract: Phosphate is a typical oxide ore characterizing that generating abundant froth during flotation. In this research a new flotation machine was employed in the flotation of phosphate. Comparing to regular flotation machine, in the reverse flotation of dolomite the recovery and grade of MgO has no significance improvement. While, in the case of reverse flotation of silicon dioxide, the new flotation machine has significance advantage. In 5 minutes of flotation time, the yield of froth is 20.66% with new machine, which equals to yield using regular machine under 8 minutes. The flotation time has been shorten by new machine. In addition, the recovery of silicon dioxide improved by 6% and the grade of silicon dioxide in phosphate concentrate decreased by 1.3% comparing the regular flotation machine. The results demonstrate that new flotation machine is more suitable and efficient for phosphate flotation

Abstract: The gold grade of the gold mine is high，because of the him particle size is fine，after flotation and gravity separation,the grade of gold is 3.5g/t,In order to increase economic efficiency and improve the resource utilization,this paper studies cyanide leaching of gold ore on the tailings,With studying experiment,the grade of gold is approximately 0.17g/t.the leaching rate of gold is nearly 95%.

Abstract: La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ composite oxide was prepared and characterized. Dilatometer and four-probe DC were exploited to investigate the thermal expansion and electrical conductivity, respectively. The thermal expansion curve was linear, but it became steeper at the high temperature region, as a result of the loss of lattice oxygen and the formation of oxygen vacancies. The conductivity increased with temperature up to about 600oC, and then decreased due to the loss of lattice oxygen. The maximum conductivity was more than 300 S cm^-1. The chemical diffusion coefficient in La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ was estimated by analyzing the conductivity relaxation behavior. The relaxation process of the conductivity change for La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ was traced as a function of time, at a fixed temperature. It was found that the chemical diffusion coefficients measured at temperatures 720-770oC vary from 710-8 to 110-7 cm2 S-1. The activation energy for oxygen diffusion in La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ, derived from the chemical diffusion coefficient is 40.8±3.6 kJ mol-1.

Abstract: A kind of complex Pb-Zn ore has been studied. The run-of-mine grade of Lead was 2.84%, with the oxidation rate of 90.95%. And the grade of Zinc was 3.22%, with the oxidation rate of 87.9%. The optimal grinding fineness was about to 94.6%. Use the best reagent combination which obtained by condition test, the final results was that the grade of Lead concentrate was 23.41% and the recovery rate was 86.75%, included silver 805.76 g/t; the grade of the Zinc concentrate was 32.65%, and the recovery rate was 80.11%.

Abstract: With the continuous depletion of primary tin ores, tin tailings has become an important source for the production of tin; however, the large-scale utilization of tin tailings is disappointedly scarce, due to its leanness in valuable minerals and insufficient methods available for processing such low-grade tailings. A flotation process has been used on a laboratory scale to investigate the effects of various reagents such as salicylhydroxamic acid, lead nitrate, sodium hexametaphosphate and pine oil on tin recovery at neutral pulp. Because cassiterite is friable and a large amount of fines and slimes were generated, usually de-sliming is used to prevent slime coating and to increase the recovery of tin. However, analyses have shown that fine particles in the sample mostly contain tin, thus de-sliming was not suggested. By applying the process, ultrafine cassiterite could be efficiently recovered from the slime tailings, and the concentrate assaying 1.82% Sn with a recovery of 76.90% was obtained.

Abstract: Improving the recovery of molybdenum is a research hotspot in the bulk flotation of Mo-copper sulphide ore. In this paper, the optimum flotation parameters for a kind of molybdenite ore obtained form Yunnan province, involving the grinding fineness, pulp concentration, dosages of kerosene and butyl xanthate, were determined in order to improve the recovery of Mo in the bulk Mo-copper flotation. In addition, a close-circuit flotation test was also conducted to simulate the practical process. A Mo-copper concentrate with Mo grade of 3.02% and recovery of 93.46% was obtained through the close-circuit flotation test, which satisfy the requirement for the bulk flotation of Mo-copper ore.

Abstract: A laboratory scale jet flotation column system was designed and air inflation for flotation column was provided by jet aerator with a chamber. In order to understand interior flow field distribution of jet aerator and flotation column, two-phase turbulent flow model was established by use of commercial computational fluid dynamics (CFD) software FLUENT 6.3.26. Modeling of the flow field was firstly established with GAMBIT 2.3.16; standard k-ε turbulence model and multiphase flow model MIXTURE were adopted for gas-liquid two-phase numerical simulation about jet aerator and flotation column. The simulation results show that gas-liquid two-phase mixing have been established by the cavity entrainment vortex flow in jet aerator with a chamber, and the distortion was really occurred although the reversed cone feed inlet have been designed, at the same time non-uniform distribution of air-bubble was also simulated. Simulation results can help to optimize the structure of the jet flotation column.

Abstract: The bed stiffness and install angle of the separator were determined by experiment. The high stiffness distributor with 6.5° reverse angle is suitable. Heavy product conveying velocity and efficiency were investigated at various air flows and throwing indexes. The results show air flow and throwing index have significant effect on velocity and efficiency in the conveying. When the conveying time was 20s, with the increasing of air flow and throwing index, the velocity and efficiency improved accordingly. Accordingly, when the conveying time was up to 40s, the efficiency tended to be stable and was above 90%.