Bioleaching of marmatite in high concentration of iron

Bioleaching of marmatite with a culture of Thiobacillus ferrooxidans and Thiobacillus thiooxidans in high concentration of iron was studied,the results show that the zine leaching rate of the mixed culture is faster than that of the sole Thiobacillus ferrooxidans,the increasing iron concentration in leaching solution enhances the zine leaching rate.The SEM analysis indicates that the chemical leaching residues is covered with porous solid layer of elemental sulfur,while elemental sulfur is not found in the bacterial leaching residues.The primary role of bacteria in bioleaching of sphalerite is to oxidize the chemical leaching products of ferrous ion and elemental sulfur,thus the indirect mechanism prevails in the bioleaching of marmatite.     

Kinetics of electrochemical corrosion of chalcopyrite in presence of bacteria

1　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｉｍｐｏｒｔａｎｔｂａｃｔｅｒｉａｉｎｂｉｏｈｙｄｒｏｍｅｔａｌｌｕｒｇｙａｒｅｍａｉｎｌｙａｅｒｏｂｉｃｃｈｅｍｏｌｉｔｈｏｔｒｏｐｈｉｃｓｐｅｃｉｅｓ ,ｏｆｗｈｉｃｈｔｈｅｍｏｒｅｉｍｐｏｒｔａｎｔａｒｅＴｈｉｏｂａｃｉｌｌｕｓｆｅｒｒｏｏｘｉ ｄａｎｓａｎｄＴｈｉｏｂａｃｉｌｌｕｓｔｈｉｏｏｘｉｄａｎｓ .ＴｈｅｐｒｏｐｅｒｔｉｅｓｏｆｔｈｅｔｗｏｓｐｅｃｉｅｓａｒｅｓｈｏｗｎｉｎＴａｂｌｅ 1.Ｔｈｅｙｃａｔａｌｙｚｅｔｈｅｏｘｉｄａｔｉｏｎｏｆｓｏｍｅｏｒａ…     

Dynamics of anodic process of gold electrode in thiourea solution in the presence of sulfur dioxide

1　INTRODUCTIONCyanidefreetechnologyofgoldextractionisanimportantissueinhydrometallurgy[1,2 ] .Thioureawasusedasanimportantmetallurgicalreagentduetoitsgoodselectivity ,low poisonousnessandhigheffi ciency[3,4 ] .Refs .[5 7]showedthatanodedissolv ingofgoldwillbeacceleratedifsulfurousacidorsul furdioxide (H2 SO3)isaddedintothioureasystem .Themechanismwasconsideredthatsulfurousacidwasinvolvedintotheelectrochemistryreactionofthesystem ,mainlyacceleratingdeoxidizationreactionofformamidinedisul…     

Enthalpies of formation of compounds in Al-Ni-Y system

The enthalpies of formation of the ternary compounds Al4NiY, Al2NiY, Al2Ni6Y3, Al16 Ni3Y, AlNiY, Al3Ni2Y, AlNi8Y3, Al7Ni3Y2, and of the binary comp ounds Al2Y containing nickel and Ni5Y containing aluminum have been determined by high temperature reaction calorimetry. The enthalpy values measured are compared to previously published results where available as well as extended Miedema model predictions. The melting points of the compounds were determined by DTA and X-ray diffraction was used to confirm the crystal structures of the compounds. The enthalpi es of formation of the ternary compounds show a maximum along the 50%Al (mole fr action) section. The ternary compounds appear along lines of constant yttrium content consistent with binary compound solubility extensions.     

Status of Fabricated Products of Titanium in China

China has had 30 years experience in titanium research,development,production and appli-cation so far.It was really a rough and bumpy road for developing Ti working industry,however,since a large amount of work was done and great many achievements were obtained by the scien-tists and engineers in this field,a firm base of Ti working industry has been established in China atlast.Especially since the beginning of 1980 s,it has been developed to a new level.On these bases,afavourable condition to speed up the development of Ti working industry arises in China.     

Progress of MOCVD in China

The paper reviewed the progresses of MOCVD technique used in the growth of group Ⅲ-V compoundsemiconductor materials and the preparation of devices in Hebei Semiconductor Research Institute (HSRI),and also introduced some of the recent progresses in China.     

The Splittings of p_± States in Infrared Spectra of Thermal Donors in Silicon

p -type CZ silicon crystals annealed at 450℃ have been investigated by low temperature infraredspectroscopy with high resolusion. It has been shown that the 2p± and 3p± bands of neutral thermal donorsTD~° are all split into two bands, which have not been reported before. In addition, the concentrations ofindi-vidual TD_i and total TD have been derived from the heights of 2po bands, and the boron concentrations de-rived from that of 320 cm~(-1) band. The room temperature resistivities of samples have been evaluated and thecomparison with practically measured resistivities have been made.     

Behavior of particles in front of metallic solid/liquid interface in electromagnetic field

1　INTRODUCTIONTheinteractionbetweentheparticlesandtheso lidifyinginterfaceisofteninvolvedintheprocessingofmetallicmaterials .Forexample ,duringthesolidi ficationofthemetalcasting ,theinclusioninthemoltenmetal(includingforeigninclusionandsec ondaryinclusion)ispossibletobeengulfedbysolidi fyinginterfacetostayinthecasting ,alsoitispossibletobepushedbytheinterfacetoretaininthemoltenmetal.Anothercaseis ,thereinforcingparticleswillbeengulfedtoenterthesolidandpossiblypushedbytheinterface ,whichw…     

Crystallization behavior of electroless Co-Ni-B alloy plated in magnetic field in presence of cerium

1 Introduction Electroless Co-Ni-B soft magnetic thin film has the property of high microhardness, wearability and excellent soft magnetism[1, 2], and possesses many advantages such as simple preparation and low cost. It can be used as a new type of soft …     

Control of deflection deformation of plate-shape castings in solidification

1　ＩＮＴＲＯＤＵＣＴＩＯＮＡｎｏｒｄｅｒｏｆｌａｒｇｅｐｌａｔｅｃａｓｔｉｎｇｓｕｓｕａｌｌｙｂａｆｆｌｅｓｔｈｅｍａｎｕｆａｃｔｕｒｅｓ,ａｓｔｈｅｄｅｆｌｅｃｔｉｏｎｄｅｆｏｒｍａｔｉｏｎｉｓｌｉａｂｌｅｔｏｏｃｃｕｒｄｕｒｉｎｇｓｏｌｉｄｉｆｉｃａｔｉｏｎｏｆｔｈｅｃａｓｔｉｎｇｓ .Ｔｈｅｃｏｍｍｏｎｗａｙｔｏｓｏｌｖｅｔｈｉｓｐｒｏｂｌｅｍｉｓｔｏｐｕｒｓｕｅａｎｏｐｔｉｍｕｍｃａｓｔｉｎｇｐｒｏｃｅｓｓｒｏｕｔｅｂｙｔｒｉａｌａｎｄｅｒｒｏｒｍｅｔｈｏｄ ,ｏｒｔｏｋｅｅｐｌａｒｇｅｒｍ…     

Role of misfit in precipitation crystallography in non-ferrous metals

The crystallography and morphology of precipitates in different systems were rationalized based on the optimum matcing conditions. The interfaces that obey these conditions were conveniently identified in reciprocal space, in terms of three Ag＇s parallelism rules. The theoretic basis of the O-lattice and CSL/DSC theory for these rules was provided briefly. Examples of small lattice misfit system （a Ti alloy）, and large lattice misfit systems （A1 and Mg alloys） were presented. The effect of lattice parameters on the orientation relationship and morphology was also discussed.     

Behavior of Fe and S in bioleaching of pentlandite

1　ＩＮＴＲＯＤＵＣＴＩＯＮＯｘｉｄｉｚｉｎｇｐｒｏｃｅｓｓｂｙａｕｔｏｔｒｏｐｈｉｃｂａｃｔｅｒｉａ ,ｓｕｃｈａｓＴｈｉｏｂａｃｉｌｌｕｓｆｅｒｒｏｏｘｉｄａｎｓ (Ｈｅｒｅｉｎｂｅｌｏｗｂｅａｂｂｒｅ ｖｉａｔｅｄｔｏＴ .ｆ .) ,ｈａｓｂｅｅｎｗｉｄｅｌｙ     

Electrochemical behavior of chalcopyrite in presence of Thiobacillus ferrooxidans

1　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｏｂｌｉｇａｔｅｃｈｅｍｏａｕｔｏｔｒｏｐｈｉｃｂａｃｔｅｒｉａｗｈｉｃｈｉｓｎａｍｅｄＴｈｉｏｂａｃｉｌｌｕｓｆｅｒｒｏｏｘｉｄａｎｓ,ｉｓｔｈｅｐｒｉｍａｒｙｏｒ ｇａｎｉｓｍｉｍｐｌｉｃａｔｅｄｉｎｔｈｅｂｉｏｌｅａｃｈｉｎｇｏｆｓｅｖｅｒａｌｓｕｌ ｆｉｄｅｓ .Ｉｔｓｃｏｍｍｅｒｃｉａｌｐｏｔｅｎｔｉａｌｉｎｔｈｅｒｅｃｏｖｅｒｙｏｆｍｅｔ ａｌｆｒｏｍｌｏｗ ｇｒａｄｅａｎｄｒｅｆｒａｃｔｏｒｙｏｒｅｓ ,ｄｅｓｕｌｆｕｒｉｚａｔｉｏｎｏｆｃｏａｌｓ ,ａｎｄｉ…     

Role of CO2 in the initial stage of atmospheric corrosion of AZ91 magnesium alloy in the presence of NaCl

The effect of CO2 and NaCl on the initial stage of atmospheric corrosion of AZ91 magnesium alloy was studied. The observation of surface morphology by optical microscopy （OM）, scanning electron microscopy （SEM） and the analysis of corrosion products by X-ray diffraction （XRD） were integrated to investigate corrosion evolution. The results showed that NaCl stimulated the corrosion by promoting the formation of thin electrolyte film, increasing the conductivity and breaking the protective film in the absence of CO2. The morphology of the corroded samples with deposited NaCl was more homogenous in the presence of CO2. It was suggested that NaCl-induced corrosion was inhibited in the presence of CO2 by the formation of slightly soluble corrosion products containing hydroxy carbonates and hydroxy chlorides that provided a partly protective layer on the surface of the magnesium alloy.     

Electrochemical behavior of chalcopyrite in presence of Thiobacillus ferrooxidans

1 Introduction The bioleaching research has a great progress in metallurgy industry. A significant number of commercial applications have emerged and are able to compete with conventional processing, especially the application for the copper recovery. Fur…     

Application of protonic conductors in metallurgy

Two types of disposable EMF hydrogen sensors for measurements of solute contents of liquid metals in situ in metal-refining processes and their general principles are introduced. The way to design new electrochemical sensors and the direction to develop new protonic conductors as new electrochemical sensors are discussed. The feasibility of protonic conductors worked as hydrogen pump in non-ferrous metal refining processes is discussed as well.     

Preparation of nickel nanoparticles in emulsion

The nickel nanoparticles with different sizes and spherical shape were prepared by the reduction of nickel sulfate with sodium borohydride in the water-in-oil emulsions of water/SDBS（sodium dodecylbenzene sulfonate）/n-pentanol/n-heptane. The effects of aging time, molar ratio of water to SDBS（R） and the concentration of nickel sulfate on the size of particles were studied. The samples were characterized by transmission electron microscopy（TEM） and inductively coupled plasma spectrometry（ICP）. The results show that the average particle size changes from 20 to 40 nm by adjusting aging time （15-30 min） and R （9-11.5）. The concentration of nickel sulfate of 1.0 mol/L is the favorite condition.     

Diffusion of tin in α-iron

The effect of the magnetic ordering on the diffusion of Sn was investigated; for this purpose, the measurements were made in an extended temperature range (1163–673 K), using several techniques like serial sectioning, heavy ion Rutherford backscattering spectrometry (HIRBS) and Rutherford backscattering spectrometry (RBS) in superposed ranges of temperature. By spanning the temperature range with respect to the previous works, the Arrhenius plot was extended over 10 decades; then the variation of the slope at the Curie temperature and a soft-up curvature in the ferromagnetic region is now clear. The curvature observed is well fitted by the model developed by Ruch et al. (J. Phys. Chem. Solids, 1976, 37, 649). The parameter that takes into account the influence of the magnetic order in the vacancy mobility during the Sn diffusion process is quite similar to that observed in Fe self-diffusion; then, no magnetic interaction between the impurity and the matrix is postulated.     

Enthalpy of Reactions in Y-Ba-Cu-O System

ＥｎｔｈａｌｐｙｏｆＲｅａｃｔｉｏｎｓｉｎＹ－Ｂａ－Ｃｕ－ＯＳｙｓｔｅｍＳｈａＷｅｉ沙维（Ｄｅｐａｒｔｍｅｎｔｏｆ．ＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＭｅｔａｌｌｕｒｇｙ，ＵｎｉｖｅｒｓｉｔｙｏｆＣａｍｂｒｉｄｇｅ．Ｕ．Ｋ．）Ｒｅｃｅｉｖｅｄ１７...     

Industrial flow of lead in China

The rules on industrial flow of lead were studied for theoretical foundation of nonrenewable resource conservation and environmental improvement. A model of lead flow in lead product life cycle was developed through lead flow analysis and was used to analyze the relationship between lead product system and its environment, thus the rules on industrial flow of lead were obtained. The results show that increasing eco-efficiency will favor both resource conservation and environmental improvement. Several indices were proposed to evaluate the lead flow. As for application, the lead-flow for China in 1999 was analyzed and the reasons for low eco-efficiency were identified. In the end, some countermeasures were proposed to improve eco-efficiency, and the future lead ore consumption and environment quality were forecasted.