Search

In order to achieve highly efficient utilization of three valuable elements Fe, Ti and V simultaneously from vanadium-bearing titanomagnetite ore sands, an improved carbothermic reduction method was proposed and verified in both laboratory scale and industrial test-bed scale. The method combined the process of direct reduction and the process of further reduction and separation. Particularly, pulverized coal injection was introduced. In experimental tests, the effects of parameters such as carbon content in briquette, reduction duration and reduction temperature on the contents of metallic Fe and FeO as well as Fe metallization rate were analyzed. Experimental results indicated that Fe metallization rate in the carbon-containing briquette could reach 75.83%. In the industrial test-bed tests, the effects of carbon content in briquette, reduction duration and reduction temperature were also investigated, respectively. In addition, processes with and without pulverized coal injection were tested. The comparative analysis indicated that the content of TiO2 in titaniferous slag was increased by applying pulverized coal injection, and it can reach 82.5 wt.%. Meanwhile, the energy performance analysis showed that the equivalent electricity consumption of the test-bed dropped significantly to 2071 kWh per ton of slag, about 26.0% less than that of traditional method. Moreover, the investment payback of the test-bed is 3.4 years. Both experiments and industrial test-bed tests demonstrated that the proposed method has the advantages of highly efficient utilization, high energy efficiency as well as good economic performance.

High-temperature particles produced from metallurgy, building materials, and chemical industry are mostly characterized by wide variations in temperature and flow rate, and the waste heat recovery processes from these particles are essentially unsteady. The heat transfer characteristics in a gas–solid countercurrent moving bed under periodic variation of inlet particle flow rate and temperature are investigated. The wide variation of inlet particle flow rate and temperature causes wide variation in input heat capacity ratio. However, their effects are different. The inlet particle temperature variation has slight effects on the instant outlet particle temperature and heat recovery efficiency, but great on that of air for the simulated cases. The variation amplitude of outlet air temperature is up to 431.41 K under the wide temperature variation of 600 K and long duration of 2.5τp (τp is the particle residence time). Improving technique should be adopted to maintain the temperature level of outlet air under wide temperature variation according to the utilization of the recovered heat. Meanwhile, the wide variation of flow rate affects the instant outlet particle and air temperatures. The variation amplitudes of outlet particle and air temperature are 88.90 K and 203.35 K, respectively. Furthermore, instant heat recovery efficiency decreases 9.6% under the wide flow rate variation that ranges from 46.58 to 19.96 t/h and long duration of 2.5τp. Varying the flow rate of air flow with an accordance variation range and duration of particle may be an efficient way if the instant heat recovery efficiency and temperature level of outlet air are requested.

High-titanium slag is not only the substitute for the gradually depleted natural rutile resources but also the important raw material for the clean production of titanium industry. In this paper, a modeling of energy consumption evaluation for production of high-titanium slag using the ilmenite as raw material was proposed, then the energy consumption of high-titanium slag production by direct reduction-melting and separation process (two-stage process) was measured on production site. The energy consumption of high-titanium slag was converted into standard coal energy or electric energy by the energy value method and the energy equivalent method, respectively, on the base of data collected from the plant. The electric energy consumption of high-titanium slag produced by the two-stage process was 1661.6 kWh per ton slag with the energy value method. Due to the energy value conversion method more reflects the value of electricity, which is suitable for applying to the energy consumption evaluation of high-titanium slag production.

Metal honeycomb is a kind of new plug-in unit for enhancing heat transfer, which is easy to adjust its specific surface area, excellent in heat conduction and flexible in geometrical transformation. The structures of honeycomb are optimized by FLUENT and orthogonal experiments. It is concluded that the heat exchange capability of honeycomb is most affected by the relative size representing screw pitch or screw diameter to metal wire diameter, less by the diameter of metal wire, and least by extensional rate under continuous heat recovery process. Moreover, it is found that the honeycomb has the best performance in heat transfer with metal wire diameter of 1.0 mm, relative size 8(corresponding to screw pitch and screw diameter 8.0mm) and extensional rate 0.7.

The current paper deals with the fractal effective thermal conductivity model for fibrous porous media containing unsaturated water moisture. The model is based on the thermal-electrical analogy and statistical self-similarity of porous media. The fractal effective thermal conductivity model can be expressed as a function of the pore structure (fractal dimension) and architectural parameters of porous media. It is expected that the model will be helpful in the evaluation of thermal comfort for textiles in the whole range of porosity.

The traditional silicothermic process of magnesium metallurgy with dolomite at high temperature and under high vacuum condition results in high operation costs, discontinuous production and huge production consumption. Based on this, a new thermal reduction process of magnesium preparation is proposed with serpentine as raw material at ordinary pressure. It is shown by thermodynamic analysis that the calcined products of serpentine is the compound of 2MgO•SiO2 and MgO•SiO2. Furthermore, the thermal reduction process at ordinary pressure is determined by using calcined products of serpentine as raw material, CaC2 as reductant and CaO as additive. Comparing with traditional silicothermic process, the new process has many advantages due to higher magnesium content of serpentine, lower price of the reductant CaC2, lower reaction temperature in calcined and thermal reduction process, and ordinary pressure reaction conditions for continuous production.

In this paper, a new process of using high grade ores, such as magnesite and water magnesium stone etc, to produce magnesium is proposed from the thermodynamic point of view. For the ores, the main component of calcined products is MgO. Considering the reaction activity, price and material stability, CaC2 is chosen as the reductant in the new process. Furthermore, the optimal reaction is determined as the reduction of MgO by CaC2 adding SiO2 based on the principle of Gibbs free energy. It is found that the initial reaction temperature is 947°C under ordinary pressure showing the reaction taking place without vacuum condition. Compared with the traditional silicothermic process, the new process is not only simple but also can achieve continuous production due to the thermal reduction under ordinary pressure, as a result that it is easy to industrial application in the present technological level and conditions.

In order to prolong the service life of reduction jar and reduce the production cost in the magnesium metallurgical industry, the structure of the horizontal Mg-reduction jar is improved in this paper, where the reduction jars with pentagonal and hexagonal cross section are designed, and the creep deformation of the jars are simulated by ABAQUS software. Through the comparison of the traditional jar with the improved jars in the creep stress and the creep displacement, it is found that the intensity is highest and the creep displacement smallest in the same service period for the pentagon jar. Considering the failure by creep, the service life of pentagon jar is longest. Therefore, the pentagon jar is put into the practical production for further verification. It is shown that the service life of the jar improves from less than 90 days up to more than 120 days, and the rate of output for a single jar is stable and improved by 12%.

The magnesium slag is rich in Ca, Mg, Si elements, in which most of the arable land in China is deficient. Based on this, a new process for producing calcium-magnesium-sulfur-silicon(Ca-Mg-S-Si) fertilizer with magnesium slag is put forward by grinding and acid treatment. It is indicated from the trial production test that the optimum grinding diameter is about 60μm to producing the Ca-Mg-S-Si fertilizer, where the content of effective ingredient is more than 40%. Furthermore, pot experiments are carried out by choosing the maize and the radish as research objects. It is shown that the efficiency of self-made fertilizer is better than similar secondary-nutrients fertilizer on the market, which has the advantages of improving the lodging resistance ability, promoting the growing in later stage, and greatly reducing growing period of crops. Therefore, the application of the new technology for producing Ca-Mg-S-Si fertilizer by magnesium slag has tremendous economic and social benefits.

The Reynolds-Orr energy equation is generalized to include the velocity slip effect at the walls, for investigating the energy gain or loss in the disturbed slip flow. Taken the Poiseuille flow, typical prototype of parallel shear flows as an example, it is found that for the very weak effect of wall slip, the disturbance energy being transferred from the basic flow overcomes the viscous dissipation, resulting in the growth of disturbance energy and the destabilizing role of wall slip. Otherwise, the viscous dissipation overcomes the energy production resulting in the decay of the disturbance energy and the stabilizing role of wall slip.

The linear stability of flows confined between two concentric rotating cylinders with wall slip is examined. The curves of marginal stability in the plane of the angular velocities at the walls are obtained as a function of slip coefficient, showing the stabilizing effect of slip on the flow stability. The eigenfunction for the first mode at the onset of instability and the corresponding cell pattern are obtained for different slip coefficients. It is found that the number of cell pattern in the radial direction increases with increasing slip coefficients.

The aim of this article was to investigate the effect of ambroxol on radiation lung injury and the expression of transforming growth factor beta(1) (TGF-beta(1)), as well as tumor necrosis factor alpha (TNF-alpha) in plasma. Totally, 120 patients with locally advanced lung cancer in radiotherapy were randomized into treatment and control groups. Patients in the treatment group took ambroxol orally at a dosage of 90 mg, three times per day for 3 months from the beginning of radiotherapy. The expression of TGF-beta(1) and TNF-alpha in plasma was analyzed. The clinical symptoms and lung diffusing capacity were monitored using high resolving power computed tomography. The level of TGF-beta(1) in the control group was increased (11.8 +/- 5.5 ng/ml), whereas in ambroxol-treated patients, the increase was not significant (5.6 +/- 2.6 ng/ml, P < 0.001). Radiotherapy-induced elevation of TNF-alpha levels, seen in control patients, was also abolished after treatment with ambroxol (5.1 +/- 1.0 vs. 2.4 +/- 0.8 ng/ml, P < 0.001). In the treatment group, carbon monoxide diffusion capacity was not significantly decreased at 6, 12, and 18 months post-radiotherapy, compared with the control group (P < 0.05). Ambroxol decreased the expression of TGF-beta(1) and TNF-alpha, and minimized the diminishment of lung diffusion capacity after radiotherapy.

The extraction of shale oil similar to petroleum by pyrolysis of oil shale is of potential value. Based on the solid-phase thermolysis model, the double extrapolated method is applied to analyze the thermogravimetric data of Huadian oil shale. It is found that the essential procedure of Huadian oil shale pyrolysis accords with internal diffusion, which can be described by three-dimensional diffusion model, and of which the activation energy is 194KJ/mol. Combined the gas-solid reaction model with the solid-phase thermolysis model, the dynamics model of oil shale pyrolysis influenced by internal diffusion is established.