方铅矿氧化过程中温度和氧化物浓度的影响研究

通过采用硫酸铁作氧化剂,在pH=2、温度50 ℃和25 ℃时对不同浓度氧化介质中方铅矿进行氧化试验。通过试验计算出反应速率常数与反应级数、反应活化能并确定反应动力学方程。分析温度和氧化介质浓度对方铅矿氧化速率的影响,在50 ℃条件下,用Fe₂(SO₄)₃作为氧化剂时,溶液的浓度为100 mg/L时反应进行很快。当溶液的浓度越高时,溶液中硫酸根离子的浓度就越高,越容易生成PbSO₄沉淀,阻碍反应的进行。而在25 ℃时,反应非常缓慢甚至不进行。     

细菌和硫酸铁氧化方铅矿的动力学和机理

《Hydrometallurgy》2004年第75卷第（1～4）期上发表了Silva G．D．介绍有关细菌和硫酸铁氧化方铅矿的动力学和机理的文章。     

硅氟酸溶液中方铅矿的阳极氧化动力学研究

用动电位扫描法测量不同条件下硅氟酸溶液中石墨电极上方铅矿的阳极氧化曲线 ,研究方铅矿的阳极氧化动力学。结果表明 ,方铅矿的阳极氧化曲线明显地分为 3段 ,氧化区di/dφ >0 ,传质区di/dφ=0 ,另一氧化过程 ,di/dφ >0。交换电流密度i0 随着温度的增加而增大 ,电化学传递系数 β的平均值为 0 16。搅拌速率、矿浆液固比对换电流密度i0 有较大的影响     

方铅矿的两矿法浸出动力学研究

对方铅矿精矿和软锰矿两矿共同浸出动力学过程进行了研究。结果表明, 在常压下40 g/L稀硝酸溶液中, 采用空气搅拌, 两矿法浸出过程为内扩散控制, 浸出产物硫膜的脱除、方铅矿粒度、浸出剂浓度以及添加剂均对铅浸出率有重要的影响。     

矿浆温度对方铅矿浮选效果的影响及机理研究

以丁基黄药(NaBX)为捕收剂,甲基异丁基甲醇(MIBC)为起泡剂,通过单矿物浮选试验,研究了矿浆温度变化对方铅矿浮选效果的影响,同时通过红外光谱(FTIR)、Zeta电位、捕收剂吸附量、X射线光电子能谱(XPS)、矿浆黏度等测试分析并结合浮选动力学研究,探究了矿浆温度变化对方铅矿浮选效果的影响机理。结果表明:矿浆温度变化会显著影响方铅矿浮选效果,低温(5℃)下的回收率较常温(20℃)下的降低约7个百分点;NaBX在方铅矿表面的吸附产物为丁基黄原酸铅,矿浆温度变化不改变其在方铅矿表面的化学吸附特性,但矿浆温度降低会减弱方铅矿表面的氧化程度,减少表面活性吸附点,使NaBX在方铅矿表面的吸附量减小从而降低浮选效果;低温下矿浆黏度增大,使气泡上升速度及气泡与矿粒碰撞速率降低,这在一定程度上会降低浮选效果;浮选动力学表明:低温(5℃)下的最大回收率和浮选速率常数小于常温(20℃)下的。     

MoSi2低温氧化动力学研究

通过热重量分析法测定了MoSi2在低温氧化不同时间后的重量变化,并根据曲线拟合分析了MoSi2的低温氧化过程。结果表明,在500℃时MoSi2材料的氧化过程受扩散和反应双重影响,氧化速率呈阶段式变化：先主要受扩散控制,氧化增重与时间呈指数关系;随后反应成为主要控制因素,氧化增重与时间呈线性关系;如此反复,表现出比400℃和600℃时快得多的氧化速率。在400℃、600℃时MoSi2的氧化速率主要取决于氧化反应,且与反应进行的时间呈线性关系,氧化144h后因钝化质量维持不变。图3,表1,参7。     

古尔胶对闪锌矿和方铅矿浮选的影响

根据吸附量测定、电动电位测量和浮 选试验研究了古尔胶与闪锌矿和方铅矿的相互作用。古尔胶在矿物表面上的最大吸附量发生在：闪锌矿ＰＨ＝７．５和方铅矿ＰＨ＝１１．５。古尔胶在方铅矿上的吸附密度比在闪锌矿上的高。古尔胶在这两种矿物上的吸附等温线具有朗格缪尔特笥。随古尔胶浓度升高,和和闪锌矿的电泳迁移率变负,而等电点未偏移。有古尔胶存在情况下,在ＰＨ１２时,方铅矿的回收率降低２０％,在ＰＨ＝８－１２,闪锌矿     

空气湿度对煤自燃特性及氧化动力学参数的影响研究

空气湿度对矿井煤自燃过程具有重要影响,为了研究空气湿度对煤自然氧化特性及氧化动力学参数的影响特征,选取文家坡煤矿4105综放工作面煤样开展程序升温实验研究,分析不同空气湿度条件下煤样氧化自燃特性,并构建公式根据耗氧速率计算不同氧化阶段的表观活化能及指前因子。结果表明：不同空气湿度条件下,CO气体和耗氧速率随温度升高均呈现出指数型增长趋势,C₂H₄气体是煤高温热解的产物,在90 °C以后才开始出现,文家坡煤矿煤样的临界温度为60~80 °C,干裂温度为100~120 °C;通过临界温度前后煤氧化动力学参数计算,煤样的表观活化能随着空气湿度的增大逐渐减小,当空气湿度超过60%以后,表观活化能又逐渐增大,且指前因子表现出类似的规律,说明煤自燃过程存在临界湿度,该湿度对煤自燃起到一定的促进作用,在该环境下煤样更加容易自燃。     

铁闪锌矿氧化动力学研究

本文采用热天平和二氧化硫吸收液电导连续测定方法,研究了温度和氧浓度对铁闪锌矿氧化的影响,计算了氧化反应速度和反应活化能,探讨了反应机理。     

Effect of galena grain size on flotation kinetics

Laboratory tests of relationship between kinetics of flotation of pure galena smaller than 38 μm in size and concentration of potassium butyl xanthate show that flotation rate undergoes considerable reduction when mineral grains are under 18 μm in size. Size grades below 18 μm show the slowest flotation rates that are nearly equal at the collector concentration of 0.5 mg/l. With the higher collector concentration, the flotation rate grows in all size grades under testing.     

Electrochemistry of galena oxidation as the basis for optimization of agent modes in flotation of polymetallic ores

The authors studied electrochemical oxidation of a galena electrode in aqueous alkaline solutions and established the limiting stage of galena oxidation and its kinetic characteristics. IR-spectroscopy analysis of oxidation products showed that complex chemical compounds were formed on the surface of the galena electrode under controllable oxidation.     

基于动力学的煤低温氧化机理研究

利用恒温反应实验装置,研究了煤低温氧化行为。根据CO2和CO气体解析过程特性,提出了煤低温氧化的两条途径,分别通过计算其反应活化能验证了这两条机理的存在性。研究了这两条机理在煤低温氧化过程中的不同的温度阶段所发挥的作用。结果表明:生成CO2的活化能很低,煤低温氧化很容易进行;CO的生成对温度有较高的敏感性。在温度低于70℃时,吸附途径在低温氧化过程中起主导作用,煤低温氧化主要生成CO2;当温度高于70℃时,燃烧途径起主导作用,煤低温氧化会产生大量CO。     

Thermodynamic and flotation analysis of influence exerted by chromate ions on separation of galena and chaclopyrite in alkaline media

The thermodynamic studies into the state of surface of galena and chalcopyrite in the presence of chromate ions and xanthate ions have been carried out along with the potentiometric measurements and flotation analysis. In the alkaline media, chromate ions are potential-determining for galena and are not such for chalcopyrite in a wide range of chromate ion concentrations. The qualitative composition of the sorption layer of the collecting and depressing agents on galena and chalcopyrite surfaces will depend on pH and redox potential of the fluid phase, and on the concentration of ions of the depressing and collecting agents. The flotation separation of galena and chalcopyrite in the alkaline media is feasible with the use of chromate ions as the depressing agents for galena. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 6, pp. 118–128, November–December, 2007.     

Effect exerted by structural features of copper-zinc ores on their oxidation and technological properties

Modeling the oxidation of pyrite copper-zinc ores under evaporization shows that structural features of ores influence the process kinetics, and displays new-formed mineral phases, namely, gannigite, biankite, chalcanthite, which relate with sulfate generating on evaporation from natural and process waters at pyrite deposits. The oxidation effect on the mineral flotation properties is described. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 4, pp. 101–110, July–August, 2008.     

煤自燃倾向性的氧化动力学测定方法不确定度评定

煤自燃倾向性的氧化动力学测定结果存在一定扩展不确定度,故在实际安全生产分析中,应注意扩展测量不确定度对所得结果的影响。对煤自燃倾向性的氧化动力学测定过程的不确定度进行评估,能够更科学、准确的获得煤自燃倾向性鉴定数据来指导企业安全生产。     

Effect of temperature on nitinol electropolishing

Electropolishing has been used in TiNi alloy in several fields for its special characteristics, but its essential details and electropolishing mechanism have not been reported yet as a demand from business competition, which, to a great degree, restricts the application and extension of the electropolishing technology. In this paper, effect of temperature on nitinol electropolishing is explored. Studies on the effect of the temperature on the electropolishing process show that the higher the temperature is, the bigger the electropolishing rate is, following a near Gauss law. The relationship between the temperature and surface roughness follows near parabolic law, the relationship between the temperature and surface reflectivity follows near Sigmoidal law.     

Effect of temperature on nitinol electropolishing

1IntroductionIn recent years,the study of surface preparation has attracted considerable attention due to its poten-tiallyi mportant effect on properties of Ni Ti medical components.Amongthose surface treat ment methods,electropolishing has attracted a great attention for its distinctive advantages.Electropolishing removesslag,burrs,scratches,heat affected zones and creates a new,smoother surface.The polishing rate can becarefully adjusted within tight tolerances to meet different requirement…     

Effect of fluid shear and particles collision on the oxidation of ferrous iron by Acidithiobacillus ferrooxidans

In this paper, the experiments were conducted in a concentric cylinder shear device. The effect on oxidation activity of ferrous iron by Acidithiobacillus ferrooxidans was tested under different shear conditions achieved through regulating the rotating speed of the inner cylinder. The results suggested that the fluid shear rate had little adverse effect on the oxidation activity of At. ferrooxidans. In this study, silicon dioxide powder was added to the medium to investigate the effect of particles collision on the oxidation activity of bacterial cells, and it was found that the oxidation rate of ferrous iron by At. ferrooxidans was greatly decreased with the increase of silicon dioxide concentration.