催化二氧化氯氧化处理难降解废水特性研究

在二氧化氯化学氧化和催化氧化体系对比试验的基础上,探讨了催化二氧化氯氧化的过程与催化特性。试验结果表明:二氧化氯化学氧化处理CODCr为3 500 mg/L的配制难降解废水时, 最佳反应pH为6-8、氧化剂用量为1 000 mg ClO2/L,反应时间为60 min,CODCr去除率可达50%左右;而采用催化二氧化氯氧化处理配制废水时,最佳反应pH为2左右,氧化剂经济用量为800 mg ClO2/L,反应时间为45-60 min,CODCr去除率可达80%以上,去除1 kgCODCr氧化荆费用为3.7元, 废水可生化性得到很大的提高,表明催化二氧化氟氧化法是一种新型高效的难降解废水处理技术。     

东北寨金矿碳质物的性质及其对金浸出的影响

东北寨碳质硫化物金矿中的有机碳质物通过 Na OH浸出、苯抽提和多种酸浸出被分为三部分。矿石中的有机碳主要是多酸浸出残渣中的碳 ,占总有机碳的 55.4 1% ;其次为苯提取物中的碳 ,占总有机碳的 37.79% ;碱提取物中的碳含量最少 ,占总有机碳的 0 .61%。原矿样、元素碳提取物和碱处理残渣在含金氰化物溶液中具有一定的吸附能力。细菌氧化前后 ,矿石中有机碳含量几乎没有变化 ,但金的浸出率大于 95%。东北寨金矿的难浸特性在于矿石中的金主要是被硫化矿物包裹 ,而矿石中碳质物对金的浸出率影响很小。     

Refractory coating based on cordierite for application in new evaporate pattern casting process

Standard raw materials, kaolin, talc, MgO, alumina, feldspar and sepiolite, were used in synthesis of four different cordierite type ceramics. Sintered cordierite was used as refractory filler in the ceramic coating for evaporative polystyrene patterns in the EPC process. The cordierite samples were tested by the following methods: roentgen diffraction analysis, diffraction thermal analysis and polarized microscope. The shape and grain size were analyzed by the program package OZARIA 2.5. In order to evaluate the possible application of cordierite as the refractory filler, four different coating processes were investigated.     

Effect of titania on the microstructure evolution of sintered magnesite in correlation with its properties

Natural Indian magnesite contains large amount of impurities like CaO, SiO₂ and Fe₂O₃. On heat treatment, these impurities chemically react and form low melting phases like monticellite (CMS), merwinite (C₃MS₂) and vitreous phases, which degrade the refractory properties of magnesite like hot modulus of rupture, corrosion resistance etc. In the present investigation, TiO₂ was used to reduce the formation of low melting phases. Compacted green pellets and bars of magnesite containing 0−5 wt% TiO₂ were sintered in the temperature range of 1500−1600 °C with 2 h soaking at peak temperature. It was observed that TiO₂ slightly increased the apparent porosity and decreased the bulk density by reducing the formation of low melting phases. High temperature flexural strength increases with TiO₂ content upto 3 wt% followed by slight decrease in strength after further increase in the amount of additive.     

某难浸金银精矿常温常压强碱预处理

采用物理与化学相结合方法,对难浸金银精矿细磨后,在单槽浮选机内进行碱式预处理,整个处理过程完全实现自吸气,且在常温常压下进行。经试验,氢氧化钠浓度1mol/L、处理时间48 h、液固比2∶1、表面活性剂1.2 kg/t为最佳预处理条件。物料经预处理后溴化浸出12 h,金的浸出率可达90%左右,银的浸出率达99%以上。     

Insights into ZrO2- and Al2O3-based submerged entry nozzle clogging for the continuous casting of RE-treating sulfur resistant casing steel

The ZrO₂- and Al₂O₃-based submerged entry nozzle (SEN) clogging during continuous casting of a RE-treating sulfur resistant casing steel is studied experimentally based on morphological analysis and the related thermodynamic calculations. The results show that the ceramic cloggings exists both in the inner-wall and outlet regions of SEN, while the latter is the main reason for terminating the casting with its clogging reaching 77% in the nozzle cross section area. The clogging is caused by RE-containing inclusions from molten steel and reoxidation products by the reaction between RE in molten steel and the initial formed cloggings on nozzle refractory. The possible existence state of RE in molten steel with its content has been discussed, and the clogging mechanism studied in detail. To prevent nozzle clogging, suggestions are given for continuous casting of the RE-treating steel with a modified RE treatment strategy for less solid inclusions and solute [RE] presented in liquid steel during refining process. Additionally, the optimization of nozzle geometry and its refractory materials may help as well.     

提高煤灰熔融温度及其机理的研究

文章针对上海焦化有限公司煤的气化和燃烧工艺现状及其原料煤——神府煤灰熔融温度低的特点，通过实验，分别考察了粘土类阻熔剂以及与焦炭或其它煤混配对煤灰熔融性的影响，探讨了提高煤灰熔融温度的方法。结合X射线衍射及CaO-Al2O3-SiO2相图探讨了添加阻熔剂及配煤后的煤灰熔融机理，讨论了阻熔剂和配煤对煤灰熔融性的影响。从成本对比角度，为工业生产推荐了一套提高煤灰熔融温度的最佳方案。     

某贫细难选铁矿石选矿工艺研究

随着我国易选铁矿石资源的日趋枯竭,开发利用贫、细难选铁矿资源具有十分重要的现实意义。采用阶段磨矿、弱磁选-强磁选-离心机的磁重联合工艺流程处理祁东境内某细粒嵌布难选铁矿,获得了综合铁精矿品位63.51%及铁回收率69.24%的良好选别指标。     

微波法辅助Fenton氧化法处理难降解废水的研究

洗煤、荧光印染生产、石油废水由于含稠环、氮、氧、硫等有机化合物,给环境造成了极大的威胁。本文通过对废水化学需氧量(COD)Mn的测定,分析了废水难以处理的原因。针对废水的特点,确定了微波辅助下,Fenton氧化法处理方案。研究了H2O2、硫酸亚铁用量,不同辐射时间、pH值对废水处理效果的影响及作用机理。通过正交实验确定了最佳条件,废水COD从3117降至784mg/L,达到了一个较好的结果。     

Characteristics of exothermic reaction fronts in the gasless combustion system

Gasless combustion model of the self-propagating high-temperature synthesis process was numerically studied in the non-adiabatic cylindrical sample. The model equations, which are very stiff in the dimension of length as well as time, were solved using finite difference method on adaptive meshes. Travelling waves with constant pattern were observed for adiabatic systems. For higher values of heat of reaction and activation energy, combustion fronts started to oscillate for adiabatic and non-adiabatic systems. Simple and complex oscillatory fronts were observed. Multi-peak and irregular oscillations were also detected to presumably result in the gasless chaotic combustion. In oscillatory fronts the temperature can overshoot the adiabatic reaction temperature to result in the complete conversion of solid reactant. In the two dimensional non-adiabatic cylindrical sample in the domain of longitudinal and angular directions, oscillatory piston waves were observed. In addition asymmetrical fingering as well as rotating waves were detected for an asymmetrical perturbation. For the adiabatic annulus cylindrical sample, the velocity of propagating fronts increased with time and the temperature overshooted the adiabatic reaction temperature if the sample were ignited from the inside. If the sample were ignited from the outside, the velocity of propagating fronts decreased with time and the temperature again overshooted the adiabatic reaction temperature. For smaller diameter of sample, the temperature increased very slowly with time for inside ignition. The temperature after ignition increased very fast overshooting the adiabatic reaction temperature for outside ignition. After several oscillations, the reaction rate decreased and the region with very slow reaction was established.