矿岩转运站的设备选择与布置

本文简要评述矿岩运输系统中常见转运站的优缺点 ,指出设备选择及布置方案与运输系统生产率的关系 ,为合理建站并获得最佳运行效益提供了依据。

Changes in organic structure and mineral phases transformation of coal during heat treatment on laboratory scale

Structural changes due to coalification and oxidation influence the coal quality, geochemically and petrologically. Understanding of the coal structures helps to predict the behaviour of coal at various processes. The objective of this paper is to study the changes in organic structure and mineral phase transformation during combustion. Different density fractions were generated and then heated at different temperatures from 200 to 1000 ℃. Petrography, Fourier transform infrared spectroscopy （FTIR） and X-ray diffraction （XRD） were carried out on all the density fractions aimed to accomplish this objective. Here, through petrography, it was observed that the vitrinite and liptinite macerals disappear at higher temperature while porous inertinite is seen. The inertinite structure is exposed which is assumed by the presence of -OH and C-O-C stretches with the aromatic nucleus （CH） and three to four adjacent H from FTIR spectra. Moreover, it can be concluded that aliphatic groups get collapsed at high temperature. In case of inorganic matter, through XRD and FTIR, it is also revealed that with increasing temperature, clay minerals converted into elemental oxides. Hence, this study is suggesting that the structures of coal are altered by the degree of contact metamorphism.

Features and mechanisms of self-sintering of molybdenite during oxidative roasting

Roasting experiments were carried out with pure reagents as raw materials.The self-sintering behaviors of molybdenite(MoS_(2))during oxidation were investigated by thermodynamic calculation,XRD,SEM-EDS and high-temperature in situ analysis.The results indicate that the desulfurization efficiency of MoS_(2) pellet decreases with the increase of roasting temperature from 600 to 700℃,owing to the expansion of sintered area.At the very beginning of roasting,sintered layer can be rapidly formed and cover the pellet surface on the windward side,and meanwhile,MoO_(2)and Mo_(4)O_(11) intensively appear and constitute the sintered layer together with MoO_(3).Moreover,it is proven that MoO_(3)-rich products containing low-valence molybdenum oxides have low melting points,thus easy to be melted during the occurrence of exothermic reaction between MoS_(2) and O_(2),which leads to the sintering of materials.

Effects of mechanical activation on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation tailings

The effects of mechanical activation in a planetary mill on the structural changes and microstructural characteristics of the components of ferruginous quartzite beneficiation railings generated by wet magnetic separation process were studied using X-ray and laser diffraction methods. The results revealed the relationship between variations in the mean particle size of activated powders and the milling time. The crystallite size, microstrain, lattice parameters and unit cell volumes were determined for different milling times in powder samples of quartz, hematite, dolomite, and magnetite from the beneficiation tailings. The main trends in the variation of the crystallite size of quartz, hematite, dolomite, and magnetite as a function mean particle size of powder samples were revealed. Changes in the particle shape as a function of the activation time was also investigated.

Effect of nickel oxide additive on smelting mechanism of chromium-bearing vanadium titanomagnetite pellets

The effect of nickel oxide additive on the smelting behaviors of chromium-bearing vanadium titanomagnetite pellets(CVTP)was investigated while analyzing the transfer behavior of nickel in iron and slag.The results show that when NiO added to CVTP increases from 0 to 6 wt.%,softening start temperature increases from 1148 to 1212℃,and the softening end temperature increases from 1280 to 1334℃;the melting start temperature increases from 1318 to 1377℃,and the dripping temperature decreases from 1558 to 1521℃.The pig iron comprises a compound of Fe-Ni-C.The slag structure depolymerizes with increasing nickel addition.The softening-melting behaviors of CVTP,the reduction of nickel into pig iron,and the depolymerization of slag structure indicate the feasibility of producing nickel-iron alloy through the blast furnace process.

Combustion behavior and influence mechanism of CO on iron ore sintering with flue gas recirculation

The properties of circulating gas have a significant effect on sintering with flue gas recirculation,and the influence of CO in sintering process was investigated.The results show that the post-combustion of CO conducts in sinter zone when flue gas passes through the sintering bed,which releases much heat and reduces the consumption of solid fuel.The ratio of coke breeze can be reduced from 5% to 4.7% with 2% CO in circulating flue gas.In addition,with the increase of CO content in circulating flue gas,the combustion efficiency of fuel is improved,and the flame front is increased slightly while still matches with the heat transfer front.These are beneficial to increasing the maximum temperature and prolonging the high temperature duration,especially in the upper layer of sintering bed.As a consequence,the productivity,vertical sintering velocity and quality of sinter are improved.

Research on the slagging characteristics of blended coals in a pilot-scale furnace

This paper applies digital image techniques to observe the slagging characteristics of blended coals in a pilot-scale furnace. Collected deposit samples were analyzed by scanning electron microscopy linked with energy-dispersive X-ray analysis （SEM-EDX）, X-ray diffraction （XRD）, and X-ray Fluorescence （XRF） to acquire the microstructure, chemical composition, and mineralogy. The deposit thickness of three blends was analyzed between their parent coal A （Datong） and coal B （Shan）, and we noted that the time to reach a stable stage decreased with the ratio of coal B. The addition of coal A into coal B could remarkably restrained the growth and thickness of ash deposits. The results of XRD analysis indicated the initial layer was predominantly comprised of the crystalline minerals quartz, anorthite, or albite except for coal B. All of the blends and coals contained quartz and Ca- to Al-silicates （Ca0.68Na0.32）（All.68Si0.32）Si2O8 in the slag layer where iron-bearing minerals （e.g., ilvaite） were altered into an amorphous phase. The result of SEM-EDX suggested that there was an elemental disparity between the coal ash and deposit.

Long-Term Effects of Inorganic and Organic Amendments on Organic Carbon in a Paddy Soil of the Taihu Lake Region,China

A long-term experiment set up in 1980 compared the effects of applying manures and chemical fertilizers on a paddy soil in the Taihu Lake region, China. Of the fourteen randomly distributed treatments consisting of different combinations of organic manure, inorganic nitrogen （N）, phosphorus （P）, and potassium （K）, and rice straw, eight were selected for the present study in 2007. Application of organic manure plus straw significantly increased soil organic carbon （SOC） content of the topsoil （0-10 cm） compared to that of chemical fertilizers alone. The content of SOC was relatively stable in the 10-30 cm layer in the chemical fertilizer treatments and in the 20-40 cm layer in the manure treatments. The stable carbon isotope ratio （513C） ranged from -24% to -28% and increased gradually with depth. The content of SOC was significantly （P 〈 0.05） negatively correlated with 513C. In the 0-20 cm layer, the 513C value significantly decreased in the treatments of manure alone （M）, manure and chemical N and P fertilizers （MNP）, manure and chemical N, P, and K fertilizers （MNPK）, manure, rice straw, and chemical N fertilizer （MRN）, and chemical N fertilizer and rice straw （CNR）, as compared with the no-fertilizer control. In the 30-50 cm layer, however, the ratio significantly increased in all the treatments except Treatment CNR. Mineralization of organic C peaked in the first 2-4 d of incubation and gradually leveled off thereafter over the first 3 weeks, being faster in the manure treatments than the chemical fertilizer treatments. The average rate of mineralization varied from 55.36 to 75.46 mL CO2 kg-1 d-1 and that of stable mineralization from 10 to 20 mL CO2 kg-1 d-1. In eight weeks of incubation, cumulative mineralization was always higher in the manure treatments than the chemical fertilizer treatments, being the highest in Treatment MRN. Combined humus in the soil was mainly （over 50%） composed of tightly combined fraction. The loosely combined humus and its ratio of humic acid （HA） to fulvic acid （FA） significantly increased with long-term application of organic manure and chemical fertilizers. It could be concluded that the cycle of organic C in the paddy soil ecosystem studied was stable over the long-term application of fertilizers and continued cultivation.

Inorganic cesium lead halide CsPbX_3 nanowires for long-term stable solar cells

ABX3-type organic-inorganic hybrid halide perovskite materials have been recognized as promising candidates for optoelectronic applications. However, poor stability of organic-inorganic hybrid perovskite hinders their forward long-term utilization and hence an effective strategy is needed to replace the organic part with an inorganic cation. Herein, all inorganic CsPbI3 nanowires with a di- ameter of 50-100 nm are synthesized on fluorine-doped tin oxide glass via a simple solution-dipping process, which are further transformed into CsPbBr3 nanowires through a so- lution-phase halide exchange method. A phase change from non-perovskite to perovskite structure is observed during the ion substitution process of I- by Br-, which is elaborated by X-ray diffraction, absorption and photoluminescence spectra. We for the first time apply the as-formed CsPbI3 and CsPbBr3 nanowires into perovskite solar cells, yielding power conversion efficiency of 0.11% and 1.21%, respectively. The inorganic CsPbBr3 nanowire solar cell shows impressive sta- bility which still remains 99% of the initial power conversion efficiency even after 5500 h aging.