云南先锋硅藻土制备钒催化剂

文章选用易开采 ,富含有机质、烧失量大的云南寻甸先锋硅藻土作载体 ,开展了先锋硅藻土制备钒催化剂的基础性研究工作。结果表明 ,原矿土经过水选处理、酸处理和煅烧后 ,即可获得精土 ;以此精土作载体 ,五氧化二钒为活性组分 ,钾盐作助催化剂 ,使用混合法可制得高强度的钒催化剂 ;

特种矿物土糊料在涤纶分散染料印花中的应用研究

为探讨特种矿物土[原矿土(OMS)和钠化矿土(MMS)]作为涤纶分散染料印花糊料的可行性,对特种矿物土糊料的基本性质和印制性能进行研究。结果表明,矿物土原糊是一种假塑性流体,PVI值<0.2;钠化矿土(MMS)比原矿土(OMS)的成糊率高,各项印制性能得以改善;硫酸铵可显著提高原矿和钠化矿糊的粘度;与海藻酸钠糊相比,钠化矿糊的储存稳定性好、透网量高,脱糊率、手感和色牢度相仿,在表面得色量和轮廓清晰度方面相对较差。该特种矿物土具有作为印花糊料的潜质,且价格低廉、储量丰富、生态环保,具有进一步研究开发的价值和前景。

离子型稀土矿土壤对铜的吸附解吸特性

以原矿土、尾矿土作为供试土壤,采用振荡平衡法,研究Cu在离子型稀土矿区土壤中的吸附、解吸特性.结果表明:Cu在原矿、尾矿土中的吸附量均随平衡浓度的增加而增大,Cu在尾矿土的吸附量大于原矿土;用Langmuir、Frundlich、Temkin模型对吸附过程进行拟合,相关系数R2均大于0.93,其中Langmuir模型拟合效果最好.Elovich方程是描述Cu在原矿、尾矿土中吸附动力学行为的最优模型,其次是准二级动力学模型,最差的是准一级动力学模型.Cu在原矿、尾矿土上的解吸量随解吸平衡浓度的增加而持续增大,Cu的解吸量与吸附量之间的关系符合二次幂方程.

Remediation of in-situ Leach Mining Contaminated Soil by Amendment-plant Synergism

This study aimed to remediate in-situ leach mining contaminated soil by amendment-plant synergism. The results showed that plant species exhibited ex-tremely significant effects on the concentration of nitrate nitrogen; to be specific, the concentration of nitrate nitrogen in soil planted with wheat was reduced from 692.19 mg/kg to lower than 100 mg/kg; when the mass ratio of amendment to soil reached 3：50 and the amendment particle size was 1-2 mm, the concentration of nitrate ni-trogen in soil planted with wheat was reduced to 43 mg/kg. The amendment type exhibited extremely significant effects on the concentration of ammonium nitrogen; to be specific, when the mass ratio of amendment to soil reached 10：50, the concen-tration of ammonium nitrogen in soil added with 2-3 mm zeolite was reduced from 23 593.75 to 3 300 mg/kg on day 15. Amendments and plants mainly exhibited desorption performance for sulfate radical in soil, and the amendment type extreme-ly significantly affected the concentration of sulfate radical; to be specific, the con-centration of sulfate radical in soil added with limestone increased from 370 mg/kg to 900 mg/kg on day 7.

In-situ Elimination Effect on Heavy Metals in Contaminated Soil from the Mining Area by Ramie

[Objective] The aim was to study on in-situ elimination effect on heavy metals in soil of the mining area by ramie （Boehmeria nivea （L.） Gaud.）. [Methods] Based on Xiangzhu No.3 and Zhongzhu No.1, we conducted research on heavy metals contents of plants growing in soil of Qibao Mountain orefield in Liuyang, Hunan Province, and on characteristics of enrichment and transfer of heavy metals （Cu, Pb, Cd, Zn） under influence of the two ramie species. [Result] It was concluded that trend of Cu content in different parts of ramie was as follows： rootskinleafbone; trend of Pb was rootleafskinbone; trend of Cd was rootskinboneleaf; the trend of Zn was rootskinboneleaf. In farmland A （with low content of heavy metal）, for per square meter of plough horizon, effect of Zhong 1 on heavy metals transferring volume and the period for restoration of the soil into national standard one （Category Ⅲ of Environmental Quality Standard for Soil） have been concluded. Specifically, for Cu, the corresponding values were 3 404.44 mg and 8.59 y, respectively; for Pb, the values were 3 638.5 mg and 13.52 y; for Cd, the values were 720.48 mg and 1.49 y; for Zn, the values were 37 324.8 mg and 0.67 y. [Conclusion] Soil contaminated by Cu, Pb, Cd, and Zn in orefield can be rapidly restored by growing ramie.

Coal-based reduction mechanism of low-grade laterite ore

A low-grade nickel laterite ore was reduced at different reduction temperatures. The morphology of metallic particles was investigated by scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS）. Experimental results indicate that the metallic nickel and iron gradually assemble and grow into larger spherical particles with increasing temperature and prolonging time. After reduction, the nickel laterite ore obviously changes into two parts of Fe-Ni metallic particles and slag matrix. An obvious relationship is found between the reduction of iron magnesium olivine and its crystal chemical properties. The nickel and iron oxides are reduced to metallic by reductant, and the lattice of olivine is destroyed. The entire reduction process is comprised of oxide reduction and metallic phase growth.

Thermodynamic of selective reduction of laterite ore by reducing gases

As the sulfide ore deposits become less economical and environmental viable as a source of nickel,increasing attention is being paid to the laterite ores.But in the pyrometallurgical process of laterite,more efforts should be paid to control the reduction of iron oxide in order to get high nickel-content nickeliferous product.For these reasons,equilibrium condition of iron oxide when laterite ore was selectively reduced by CO2/CO,H2O/H2 and CO2/H2 was studied from the perspective of iron activity with an assumption that the activities of Fe O and Fe3O4 equal 1 in this work,and it well accounts for the inescapability of Fe metallization.Activity coefficient of iron in Ni-Fe binary solid alloy was calculated by Miedema model based on the known thermodynamics datum filed.According to Raoult＇s law,the relationship among the Fe/Ni ratio,reduction temperature and reduction gas composition was calculated when laterite ore was selectively reduced by the three different reduction systems.The calculation result was discussed and also compared with the experimental result.The trend of metal iron content in the reduction product of laterite ore varying with temperature and gas composition was well predicted by the calculation result.

Mineral Composition and Weathering of Soils Derived from Xiashu Loess

Mineralogical, physical and chemical analyses of the soils derived from Xiashu loess were carried out. The primary minerals of these soils were found to be mainly composed of light minerals, such as quartz, feldspar and mica, with traces of heavy minerals. Clay minerals, more complicate in composition, were dominated by hydromica, accompanied by smectite, vermiculite, chlorite, kaolinite, 2:1/1:1 randomly interstratified minerals and small amounts of quartz, goethite, lepidocrocite and hematite, Clay minerals were characterized by low crystallinity and fine particle size. In light of the quartz/ feldspars ratio of the 0.01-0.05mm silt fraction, and the clay mineral composition, the freeness of iron oxide, and the silica/ sesquioxide and silica/ alumina ratios in < 0.002mm clay fraction, it is concluded that the weathering intensity of these soils was lower than those of red soil and yellow earth, but higher than that of brown earth, and that the soil allitization, depotassication and hydroxylation of clay minerals increased from west to east and from north to south geographically. However, this general tendency did not coincide exactly with the gradual alteration of the geographic coordinates, and in some places, a reverse tendency also appeared, which could be attributed to the influence of some soil forming factors such as parent material and microtopography.

Red Ratings for Loess-Paleosol Sequences on China’s Loess Plateau and Their Paleo-Climatic Implications

Comparisons of red ratings (RR) with Fe_d, Fe_d/Fet, clay content, andmagnetic susceptibility (x) of two loess-paleosol sequences at Luochuan and Lingtai on China's LoessPlateau were conducted to study the possible relationship between RR and pedogenic degrees of thetwo loess-paleosol sequences, and to discuss whether the RR could become new paleo-climaticindicators. Results showed that the RR of the two loess-paleosol sequences had positive, highlysignificant (P < 0.01) correlations with: 1) citrate-bicarbonate-dithionite (CBD) extracted iron(Fe_d), 2) ratios of CBD extracted iron to total iron (Fe_d/Fet), 3) clay (< 2 mum), and 4) magneticsusceptibility (x). This suggested that the RR of these loess-paleosol sequences could indicatedegreesof loess weathering and pedogenesis and were potential paleo-climatic proxies. The strongcorrelations of RR to Fe_d and x also implied that during pedogenic processes, pedogenic hematite inloess and paleosols were closely related to the amount of total secondary iron oxides and pedogenicferrimagnetic minerals (predominantly maghemite).

Efficient enrichment of nickel and iron in laterite nickel ore by deep reduction and magnetic separation

The process of deep reduction and magnetic separation was proposed to enrich nickel and iron from laterite nickel ores.Results show that nickel-iron concentrates with nickel grade of 6.96%,nickel recovery of 94.06%,iron grade of 34.74%,and iron recovery of 80.44% could be obtained after magnetic separation under the conditions of reduction temperature of 1275℃,reduction time of 50 min,slag basicity of 1.0,carbon-containing coefficient of 2.5,and magnetic field strength of 72 kA/m.Reduction temperature and time affected the possibility of deep reduction and reaction progress.Slag basicity affected the composition of slag in burden and the spilling and enriching rate of nickel-iron from a matrix to form nickel-iron particles.Nickel-iron particles were generated,aggregated,and grew gradually in the reduction process.Nickel-iron particles can be effectively separated from gangue minerals by magnetic separation.

Efficient separation of alumina and silica in reduction-roasted kaolin by alkali leaching

Alkali leaching was employed to investigate the separation of alumina and silica in roasted kaolin obtained by roasting kaolin alone in air at 1273 K for 60 min and in clinker prepared by roasting the mixed raw meal of kaolin,ferric oxide and coal powder with Fe2O3/Al2O3/C molar ratio of 1.2:2.0:1.2 in reducing atmosphere at 1373 K for 60 min.The thermodynamic analyses and alkali leaching results show that the composition of the Al-Si spinel in roasted kaolin is close to that of 3Al2O3·2SiO2 and the spinel is dissolved with increasing leaching time,resulting in difficulty in deeply separating alumina and silica in kaolin by the traditional roasting-leaching process.On the contrary,the efficient separation of alumina and silica in kaolin can be reached by fully converting kaolinite into insoluble hercynite and soluble free silica,namely quartz solid solution and cristobalite solid solution,during reduction roasting,followed by alkali leaching of the obtained clinker.Furthermore,experimental results from treating high-silica diasporic bauxite indicate that the reduction roasting-alkali leaching process is potential to separate silica and alumina in aluminosilicates.

Pilot scale test of producing nickel concentrate from low-grade saprolitic laterite by direct reduction-magnetic separation

The enrichment of Ni from a low-grade saprolitic laterite ore,which has been pre-treated by high pressure grinding roller（HPGR） to be 74% passing 0.074 mm and contains 0.92% Ni,18.47% Fe,10.61% MgO and 42.27% SiO2,was conducted by using pelletizing,rotary kiln reduction and magnetic separation process on a semi industrial scale,and the effects of reduction duration,mass ratio of coal to pellets（C/P）,the types of magnetic separator,the sections of grinding-separation and the grinding fineness on the recovery of Ni and Fe were examined.It is shown that nickel concentrate containing 3.13 % Ni and 59.20 % Fe was achieved at recoveries of 84.36 % and 71.51% for Ni and Fe,respectively under the following conditions：reducing at （1120±40） ℃ for 120 min,C/P being 1.0,wet grinding of reduced pellets up to 70%-87% passing 0.074 mm and a magnetic field intensity of 238.8 kA/m during the first section of grinding-magnetic separation,and a grinding fineness of 84%-91% passing 0.045 mm and a magnetic intensity of 39.8 kA/m during the second section of grinding-magnetic separation.The enriched Ni containing concentrate has a low content of S and P,and can be used for further processing to produce high-grade ferronickel alloy.

Extraction of valuable metals from low-grade nickeliferous laterite ore by reduction roasting-ammonia leaching method

Nickel and cobalt were extracted from low-grade nickeliferous laterite ore using a reduction roasting-ammonia leaching method.The reduction roasting-ammonia leaching experimental tests were chiefly introduced,by which fine coal was used as a reductant.The results show that the optimum process conditions are confirmed as follows:in reduction roasting process,the mass fraction of reductant in the ore is 10%,roasting time is 120 min,roasting temperature is 1 023-1 073 K;in ammonia leaching process,the liquid-to-solid ratio is 4:1(mL/g),leaching temperature is 313 K,leaching time is 120 min,and concentration ratio of NH3 to CO2 is 90 g/L:60 g/L.Under the optimum conditions,leaching efficiencies of nickel and cobalt are 86.25% and 60.84%,respectively.Therefore,nickel and cobalt can be effectively reclaimed,and the leaching agent can be also recycled at room temperature and normal pressure.

Characterization of Soil Clay Minerals of the River Nile Sediments, Sohag Region, Egypt： Decomposition of X-Ray Diffraction Patterns

Up till now all the clay mineral studies on the soils of the River Nile flood plain in Egypt could not trace the very rapid mineral change observed in these soils. So, the clay mineralogy of the River Nile flood plain soils in Sohag region, Egypt, has been studied using the method of numerical analysis of X-ray diffraction recordings （curve decomposition） as a new, powerful tool for precise mineral identification. The X-ray patterns of the studied soil clay fraction show that 2：1 clay minerals are much more abundant than kaolinite and that this clay fraction contains fair amounts of K-feldspar and quartz. XRD pattems obtained on the 〈 2 μm fraction of the River Nile sediments indicate the presence of smectite, mixed-layer illite-expanding minerals, kaolinite, mica-illite and chlorite. The decomposed XRD patterns reveal significant changes in the mineralogy of the clays. The major clay phases present in the 4-11 20 range are well crystallized illite （10 A）, poorly crystallized illite （10.2-10.4 A）, two mixed-layer I-S （illite/smectite） minerals, one with a peak near 13.5 A （rich-smectite） and the other near 11 A （rich-illite）.

A study on Cr(Ⅵ)reduction from aqueous solutions by bauxite

The reduction of Cr（Ⅵ） in aqueous solution by using bauxite ore was investigated.Experimental results for Cr（Ⅵ）reduction in aqueous solution depending on some factors such as time,sulfuric acid amount,bauxite dosage,initial Cr（Ⅵ）concentration,formic acid concentration,daylight and temperature were presented.The obtained results show that sulfuric acid amount,bauxite dosage and initial Cr（Ⅵ） concentration of solution are most effective parameters on the reduction process.Also,it has been found that the 60 g/L of bauxite dosage is sufficient to reduce up to 100% of Cr（Ⅵ） from acidic solution under the condition of low initial Cr（Ⅵ） mass concentrations such as 10 mg/L.The reduction reaction is completed within 30 min at 25 ℃ under the experimental conditions：bauxite dosage of 60 g/L,amount of sulfuric acid 40-60 stoichiometric and initial mass concentration of Cr（Ⅵ）,10 mg/L.It was determined that reduction percentage is decreasing with increasing initial Cr（Ⅵ） concentration.The chemical oxygen demand of bauxite ore was found to be 26 mg COD/g.

Effect of Alternative Raw Materials on Resistance of Concrete to Chemical Actions

The results of experimental works aimed on finding the optimal composition of concretes containing alternative materials as mineral additives for assurance their high resistance to chemical aggressive attack are presented in the paper. 4 kinds of additives （blast furnace slag, fly ash, non-treated and treated serpentinite waste） and 4 kinds of aggressive environments （distilled water, HCI, MgSO4 and NaOH） representing the concrete corrosive processes was checked within experimental process. The open laboratory curing was used as a reference environment. Moreover, the amounts of additives were varied, so 16 various recipes were checked on the whole. The resistance of samples was tested in the terms of flexural strength, compressive strength and evaluation of decrease/increase of strengths after long time （28 months） exposition in monitored aggressive media. Based on obtained results, it is possible for each of aggressive environments recommend the most promising recipe from various points of view, in accordance with user＇s priorities. From the percentage increase of 28-day compressive strengths point of view, there are： for HCI action - recipe with 20% of non treated serpentinite waste with plasticizer application, for MgSO4 action - recipe with 20% of blast furnace slag without plasticizer application and for NaOH action - recipe with 10% of non treated serpentinite waste without plasticizer application. Application of alternative materials as partial substitution of cement appears to be beneficial for achievement the resistance to aggressive chemical actions. With the keeping or enhancement of technical parameters it extra represents both the environmental and economic benefit.

Characterization of fluidized reduction roasting of nickel laterite ore under CO/CO_(2)atmosphere

Fluidized reduction roasting is an efficient metallurgical technique.However,its application to nickel laterite ore has rarely been reported.In this paper,the effects of reduction temperature,reduction time,CO concentration,and material particle size on the roasting characteristics of ferronickel fluidization reduction were investigated.Combined with X-ray diffraction,scanning electron microscopy-energy dispersive spectrometry(SEM-EDS)characterization,the mineral phases and microscopic morphology of nickel laterite ore and its roasted ores were analyzed in depth.The results indicated that under the condition of a CO/CO_(2)ratio of 1:1,a reduction temperature of 800℃,and a reduction roasting time of 60 min,a nickel-iron concentrate with a nickel grade of 2.10%and an iron content of 45.96%was produced from a raw material with a nickel grade of 1.45%,achieving a remarkable nickel recovery rate of 46.26%.XRD and SEM-EDS analysis indicated that nickel in the concentrate mainly exists in the form of[Fe,Ni],while the unrecovered nickel in the tailings is primarily present in the form of[Fe,Ni]and Ni_(2)SiO_(4)in forsterite.This study established a theoretical foundation for further exploration of fluidized reduction roasting technology.

A Density Functional Theory Study of Codoping Characteristics of Sulfur with Alkaline Earth in Delafossite CuAlO_2

The structural,electronic properties and formation energies of sulfur and alkaline earth codoped delafossite CuAlO_2 have been investigated using the first-principles density functional theory calculations.Our results reveal that the volume of codoping systems increases with the increasing atomic radius of metal atoms.The formation energies under different growth conditions have been calculated,showing that the codoping systems are formed easily under O-rich growth conditions.Electronic band structures and density of states have been obtained.The decreased bandgaps,enhanced covalence and appearance of electron acceptors after codoping are all good for p-type conductivity.