Zhang Tingan

Extraction of Vanadium from LD Converter Slag by Pressure Leaching Process with Titanium White Waste Acid

The process of extraction vanadium from LD converter slag by pressure leaching with titanium white waste acid was investigated. The mineralogy analysis indicates that several kinds of spinel containing Fe, V, Ti, Mn and Cr, mainly exist in the converter slag. Potential-pH diagrams of V-Fe-H2O, V-Ti-H2O, V-Mn-H2O, V-Cr-H2O system have been calculated at elevated temperature condition (150 °C). The thermodynamics diagrams show that soluble ions of V and Fe2+, Fe3+, Mn2+, Cr2+ and Cr3+ can be extracted by the acidic leachate during the pressure leaching process. The results of orthogonal experiment reveal that the impacts of temperature and initial acid concentration on the vanadium extraction process are effective. The effect of temperature on the leaching process was further investigated with a increased temperature from 100 °C to 160 °C, and the results indicate that the content of titanium in the residue is 4.56% to about 12.0%, while other elements tend to be enriched in the leaching solution. Under the optimization condition (temperature 140 °C, liquid-solid ratio 10:1, concentration of acid at 200 g·L−1, stirring speed 500 r/min and the reaction time of 90 min), the leaching rate of vanadium is 96.85%.

Research on new type materials preparation for magnesium production by Silicothermic process

During the magnesium preparation process of the silicothermic process, dolomite was made into pellets after calcination process, about 5% fine materials would be produced which can’t be used and lead to high energy consumption and high-cost. Based on in-situ reduction of dolomite-based desulfurization theory, this paper proposed a new technology that dolomite was made into the pellets first and then was calcined to prepared the pellets with higher reactivity and stability. The results indicate that: In contrast with dolomite pellets prepared by single binder, dolomite pellets prepared by composite binder are dominant in functions without fine materials produced, the size of pellets is uniform, the falling strength can reach 2.5 times per 0.5 m, and the compressive strength gets 80N as well.

Numerical Simulation on Carbonation Reactor of Calcified Residue

This paper aimed at studying the carbonation process — the core process of “Calcification-Carbonation”, and a venturi carbonation reactor to process calcified residue was innovatively designed and produced. The simulated calculations for dynamic characteristics of gas-liquid-solid three-phase flow were discussed under different superficial gas velocities. Results showed: with the increase of gas velocity, gas holdup increased and solid holdup decreased slightly. Fluid turbulence intensity and collision and coalescence of bubbles were enhanced with the increase of gas velocity, which was beneficial to the mass transfer and reaction among gas, liquid and solid. The measured values agreed well with the simulated calculations obtained by CFD, which indicated that it was feasible to use this model to simulate the gas-liquid-solid three-phase flow field in this reactor and the results of numerical simulation were reliable. The above results provided a theoretical basis for the design of the reactor under a high temperature and a high pressure.

A new green process to produce activated alumina by spray pyrolysis

Abstract A green process that uses the spray pyrolysis method to prepare activated alumina is proposed in this research. The effects of spray temperature, carrier gas pressure, and AlCl3 solution concentration are experimentally investigated using pure reagents. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and specific surface area (BET) analyses. The results indicate that the spray temperature is the most important factor on the conversion ratio of alumina during the spray pyrolysis process. The conversion ratio of alumina achieved over 99% at the following optimal conditions: temperature of 1000°C, pressure of 0.3 MPa, and AlCl3 solution concentration of 10 wt%. The activated alumina with 8–20 nm particle size (γ-Al2O3+α-Al2O3) was prepared using the same process, which well met the requirement of the catalyst carrier. The green utilization of high-alumina fly ash and acid recycling can be achieved by using this process.

Effects of Blowing Conditions on the Dispersion States of Materials Charged into Bottom Blown Oxygen Smelting Furnace

Recent years, bottom blown oxygen copper smelting process has been widely used in China. Besides many advantages such as autothermal operation, this technology is still in developing stage. This topic aims at promoting the dispersion of materials charged into the bottom blown smelting furnace used in the process. Based on the similarity theory, a 1/5 scaled physical model of smelting furnace was constructed. Polypropene particles were used as charged materials. High-speed camera was used to record the phenomenon of the particles dispersion under different gas-flow rates, nozzle diameters and installation angles of nozzles. Image processing software was used for obtaining the particles concentration under different conditions. Results show that when the gas flow rate increases, charged materials disperse better. With the same gas flow, the increasing of nozzle diameter promotes the dispersion effect of materials. The effects of installation angles are opposite for nozzles with diameter of 2.50 and 5.92 mm.

Numerical Simulation on Multiphase Flow in the Two Side-Blown Oxygen-Enriched Copper Smelting Furnace

In order to understand flow regularity and select oxygen lancer operating parameters of the two side-blown oxygen-enriched copper smelting process, commercial software Ansys/Fluent13.0 was used to simulate the flow characteristics of multiphase flow in the bath under different nozzle arrangement. The results showed that when the nozzle arrangement was compact, the stirring effect of gas was enhanced and the local velocity and turbulent kinetic energy of the fluid increased while the fluctuation of copper matte layer was intensified. Meanwhile, local gas holdup also increased, which caused uneven distribution of gas near the oxygen lacer. However, when the nozzle arrangement was sparse, the stirring strength decreased in the smelting zone. The flow fields obtained by PIV technology agreed well with the CFD results, which indicated that the numerical simulation results were reliable. The results above provided theoretical foundation for the further study on the two side-blown copper smelting process.

A Novel Self-Stirring Tubular Reactor Used in Bauxite Digestion Process

A novel self-stirring tubular reactor driven by pressure energy used in bauxite digestion process is presented originally in this paper. This reactor combines the advantages of autoclaves and conventional tubular digestion equipment, it can restrain scale at high temperature and high pressure and intensify mass and heat transfer. Stirring of the novel reactor only needs the pressure energy of the liquid. Performance of self-stirring reactor driven by pressure energy was studied in this paper. High-speed photography was adopted in the paper to research the effects of various factors on rotating speed in the self-stirring reactor driven by pressure energy. The results demonstrated that fluid pressure has the most outstanding effects on stirring speed of the novel reactor, and the effects of fluid density and viscosity on stirring speed are minor.

燃烧合成法制备NdB 6 超细粉体及反应机理

以B 2 O 3 、Nd 2 O 3 和Mg为原料, 采用燃烧合成法制备出NdB 6 超细粉体。考察了反应气氛、制样压力和物料配比对反应产物微观形貌和物相的影响。采用XRD、SEM对产物进行了表征, 结果表明: 燃烧产物由NdB 6 、MgO以及少量Mg 3 B 2 O 6 和Nd 2 B 2 O 6 组成, 稀硫酸处理去除可溶性成分后, 产物为单一的NdB 6 相, 纯度为99.1%。随着制样压力的增大, NdB 6 颗粒尺寸逐渐变小。制样压力为20 MPa时, 制备的NdB 6 粉末平均粒度小于500 nm。Mg-B 2 O 3 -Nd 2 O 3 三相反应历程: 首先Mg还原Nd 2 O 3 生成单质Nd和MgO, 然后引发Mg还原B 2 O 3 生成单质B和MgO, 同时生成的Nd和B反应得到NdB 6 , 反应的表观活化能为691.59 kJ/mol, 反应级数为3.2。

Research on Mechanically Activated Digestion Performance of Diasporic Bauxite and Kinetics

This paper proposes a “mechanical activation-homogeneous digestion” technology as a strengthening method for diasporic bauxite digestion process of alumina production. Effects of digestion temperature, digestion time and mechanical activation speed on digestion performance of diasporic bauxite were investigated by using “homogeneous digestion” equipment, and the digestion kinetics of diasporic bauxite was studied as well. The results indicate that the mechanical activation can greatly improve the digestion performance of diasporic bauxite, digest mine with larger particle size. The optimal mechanically activated digestion temperature is 20°C lower than that of direct digestion. The relative digestion rate of alumina goes up to above 97% when digested at 245°C for 60 minutes with a mechanical activation speed of 80rpm.The apparent activation energy of mechanically activated digestion is 57.30kJ/mol, 21.09kJ/mol lower than the direct digestion. The kinetic equation of mechanically activated digestion is (1−η)−1/3−1=1.5532x10−4exp(4.764x105/T)t.

Effects of Roasting Pretreatment in Intense Magnetic Field on Digestion Performance of Diasporic Bauxite

This paper investigates the changes of phase and apparent morphology under the combined effects of an intense magnetic field and temperature field and the effect law of different roasting conditions on the digestion performance of roasted diaspore. The results indicated that roasting pretreatment under high magnetic fields can change the microstructure and improve the digestion properties of bauxite. The reasonable roasting conditions with intense magnetic field are as follows; the roasting temperature is 550°C, roasting time is 60min and the magnetic field intensity is 6T. The digestion rate of alumina of the roasted ore is 84.17% and the digesting liquid ratio is 1.39 while the digesting temperature is 190°C with the digestion time of 60mins. The digestion rate of alumina of the roasted ore increases to higher 52.85% than that of the raw ore, but the digesting liquid ratio is decreased to lower than 0.99 of the raw ore under the above roasting conditions. The digestion temperature of roasted ore decreases by 30°C compared to the raw ore.