酶催化浸出米糠油

对水酶催化浸出米糠油进行了研究。影响浸出最显著因素是酶催化时间、水中米糠浓度、己烷体积、酶用量。米糠和水混合物在 pH =4 .5 ,温度 5 0℃左右、催化反应 6h ,2 %纤维素酶 ,2 %果胶酶 ,水糠比率 5∶1(v/w)、己烷 /米糠 (v/w) 2 5∶1,油回收率达 10 0 %

活性炭催化浸出原生硫化铜矿研究进展

文章综述了活性炭催化浸出原生硫化铜矿的机理和近十年的研究进展,指出用活性炭催化原生硫化铜矿的工艺投入工业生产的可行性。

低品位原生硫化铜矿催化浸出的研究进展

综述了近20年低品位原生硫化铜矿催化浸出的研究进展,主要介绍了Fe3+催化效应、金属阳离子催化效应、活性炭催化效应、混合催化效应和细菌强化浸出这五种催化方法及其催化机理,并指出了各种催化效果的优点及不足之处,最后提出现在尚存的问题及解决方法。

银在浸出黄铜矿中的催化作用

本文研究了用Fe_2(SO_4)_3、MnO_2、FeCl_3、CuCl_2等浸出黄铜矿时Ag^+的作用。Ag^+在氯化物溶液中不起催化作用。但在酸性Fe_2(SO_4)_3及MnO_2溶液中可使反应速率常数提高200倍,文中导出了在Ag^+催化作用下硫酸高铁浸出黄铜矿的动力学方程。确定了速率控制步骤是离子通过产物硫层的扩散过程,活化能为35.7kJ/mol。探讨了银催化浸出黄铜矿的反应机理。

氟碳铈矿氧化焙烧-盐酸催化浸出新工艺研究

针对氟碳铈矿盐酸处理过程中稀土浸出率低,高价值非铈稀土进入富铈渣造成高价元素低值利用,以及伴生资源氟综合利用等问题,研究开发了低温焙烧-催化浸出技术,考察了焙烧温度、浸出温度、盐酸用量、液固比及添加浸出助剂等对稀土浸出率的影响。在优化工艺条件:焙烧温度500℃,浸出温度50℃,酸矿质量比1.75∶1,液固质量比2∶1时,总稀土浸出率达到65.1%,非铈稀土浸出率为93.3%,浸出渣中CeO2/TREO为94.1%。本工艺简化了工艺流程,节省了大量化工原料消耗,降低了成本,整个过程实现了无氟排放,具有低消耗、高效能等特点,取得了良好的环保、经济和社会效益。

金铜精矿中性催化加压浸出预处理工艺

针对金铜精矿采用中性催化加压预处理工艺,经试验,在温度180℃、氧分压1.8 MPa、催化剂0.14 mol/L的基本条件下,Cu浸出率为99.4%,浸液中残留∑Fe质量浓度仅为3.52 g/L,对后续回收Cu的精炼工艺非常有利。氧化渣以氯化浸金工艺浸出Au、Ag,浸出率分别为98.2%、90.3%,有价元素回收率高,工艺简单,环境效益好。

银催化原生硫化铜矿细菌浸出的研究进展

综述了银催化原生硫化铜矿细菌浸出机理及影响因素的研究进展,指出银是一种有效的催化剂,其催化效果与Ag^+浓度、含银催化剂类型、温度以及酸度等因素有关。

铜矿石和精矿氮类物催化加压浸出的应用与经济估算

目前评估生产铜的新处理方法兴趣日益浓厚。铜矿石和精矿湿法加压氧化是一种环境友好、经济上可行的方法。几种侯选工艺已经出现,目前正在以中间工厂或生产规模应用。其中,第一个已经工业生产验证的方法是氧压浸出中采用氮类物催化(NSC),通过SX-EX生产铜。该法具有很多优点,是一种很有应用前景的方法。本文介绍了该工艺的最新进展,工艺开发史及在铜精矿和铜矿石中的应用,重点讨论了从黄铜矿精矿中有效回收贵金属的无氰化物方法。最后,介绍了两个最新工业应用研究及其现场经济估算。

细菌浸出的试验研究

简要介绍了细菌浸出的微生物学研究、摇瓶浸出试验、空气提升浸出试验情况 ,并对Ag催化浸出、表面活性剂催化浸出、电化学催化浸出、细菌浸出机理等问题进行了分析和探讨。

湿法冶锌新浸取技术及其进展

本文概述了锌精矿湿法冶炼的多种新浸取工艺 ,进行相关综合评述 ,并介绍国内外一些湿法冶锌工艺发展新趋势。

SPW助剂应用于氰化浸金研究

为了实现矿产资源的综合利用 ,有效回收有价元素 (Au、Ag、Pb、S等 ) ,用SPW型协同氧化催化氰化浸出新助剂 ,对秦岭TL地区金矿石进行了实验室试验和扩大试验。其结果表明 ,在矿样粒度 - 32 0目大于 85 % ,NaCN用量为 7kg/t,矿浆浓度为 4 0 % ,SPW助剂用量≤ 5kg/t条件下 ,对含金品位为 (10 0± 2 0 )g/t的金精矿 ,浸出时间为 (10± 2 )h ,金的浸出率可达 98%以上。

Bicarbonate activation of hydrogen peroxide: A new emerging technology for wastewater treatment

The serious limitations of available technologies for decontamination of wastewater have compelled researchers to search for alternative solutions. Catalytic treatment with hydrogen peroxide, which appears to be one of the most efficient treatment systems, is able to degrade various organics with the help of powerful ·OH radicals. This review focuses on recent progress in the use of bicarbonate activated hydrogen peroxide for wastewater treatment. The introduction of bicarbonate to pollutant treatment has led to appreciable improvements, not only in process efficiency, but also in process stability. This review describes in detail the applications of this process in homogeneous and heterogeneous systems. The enhanced degradation, limited or lack of leaching during heterogeneous degradation, and prolonged catalysts stability during degradation are salient features of this system. This review provides readers with new knowledge regarding bicarbonate, including the fact that it does not always harm pollutant degradation, and can significantly benefit degradation under some conditions.

清洁的炼铜工艺

本文简要介绍了世界上各种处理硫化铜矿的新型湿法炼铜工艺的发展现状及其日益看好的应用价值。

Oxygen pressure acid leaching of artificial sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation

The mechanism of oxygen pressure acid leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation was investigated in this study.Artificial sphalerite was fabricated with varying amounts of iron content via the sintering of ZnS and FeS and used for the pressure acid leaching experiment.The variations in the potential of the pressure leaching system were investigated by using a self-designed potential autoclave.The results showed that compared to the non-iron sphalerite,there was a violent redox reaction between the 25.70%Fe-artificial sphalerite and dissolved oxygen during the process of pressure leaching;and the catalytic mechanism was attributed to the redox couple Fe^3+/Fe^2+,where Fe3+oxidizes the H2S gas film and the reduced Fe2+state is subsequently oxidized by the dissolved oxygen.Furthermore,the effect of temperature,H2SO4 concentration,and oxygen partial pressure on the artificial sphalerite with different iron contents was studied.The sphalerite samples with iron content were observed to dissolve more easily in sulfuric acid compared to the non-iron samples.Moreover,the activation energy of artificial sphalerite was observed to be lower in the sample with 25.70%iron content(22.26 kJ/mol)compared to that with no iron(32.31 kJ/mol);and the apparent reaction orders were obtained with respect to H2SO4 concentration(1.10 and 1.36)and oxygen partial pressure(1.29 and 1.41),respectively.A comprehensive kinetic model was developed on the basis of the experimental data and the fitted leaching ratio plot;and the kinetic equations for the leaching of sphalerite catalyzed by Fe^3+/Fe^2+self-precipitation were determined.

Nickel and aluminium recovery from spent reforming catalyst through selective leaching,crystallization and precipitation

An attempt has been made to investigate and optimize the recovery of Ni and Al through sulphuric acid(3.0-5.5 mol/L)leaching under different operating conditions.From the leaching experiments,it was possible to extract 98.5%of NiO and 40.7%of Al_(2)O_(3)under the conditions of 5.5 mol/L H_(2)SO_(4),reaction time of 4 h,solid-to-liquid ratio 0.2 g/mL,temperature of 358 K,particle size<100μm,200-250 r/min with 5.0 g catalyst dosage.The leached liquor Al was separated by selective crystallization using 1.4 mol/L KOH and Ni was separated by selective precipitation using 0.3 mol/L H_(2)C_(2)O_(4).From the studies,it is possible to recover around 97.9%of NiO having 98.3%purity,around 25%of Al_(2)O_(3)was also recovered as alum-(K)having 99%purity and 14.7%of Al_(2)O_(3)as a salt of Al-K-C_(2)O_(4)-SO_(4).Sulphuric acid was found to be a suitable leaching agent for selective leaching and it was also observed that alum-(K)can be selectively crystallized from sulphate solutions.The study also indicated the effective extraction and recovery of nickel and aluminium which were well supported by characterization studies using TG-DTA/DTG and XRD techniques.

Leaching of chromite ore in concentrated KOH by catalytic oxidation using CuO as catalyst

CuO was used as a catalyst in the concentrated KOH solution to enhance the leaching of chromium from the chromite ore.The impacts of temperature,KOH-to-chromite ore mass ratio,CuO-to-chromite ore mass ratio,and gas flow rate on the chromiumleaching rate were investigated.The results indicated that CuO played an important role in improving the chromium leaching rate.The leaching rate reached98%after leaching for6h when CuO was applied,whereas it was only60.8%without CuO under thesame reaction conditions:temperature230°C,KOH-to-ore mass ratio6:1,stirring speed700r/min,gas flow rate1L/min.Accordingto the kinetics study,the catalytic oxidation was controlled by surface chemical reaction and the activation energy was calculated tobe15.79kJ/mol when the temperature was above230°C.In contrast,without CuO,the rate-determining step was external diffusionand the apparent activation energy was38.01kJ/mol.

New technique of comprehensive utilization of spent Al_2O_3-based catalyst

A new technology was developed to recover multiple valuable elements from the spent Al2O3-based catalyst by X-ray phase analysis and exploratory experiments. The experimental results show that in the condition of roasting temperature of 750℃ and roasting time of 30 min, molar ratio of Na2O to Al2O3 of 1.2, the leaching rates of alumina, vanadium and molybdenum in the spent catalyst are 97.2%, 95.8% and 98.9%, respectively. Vanadium and molybdenum in sodium aluminate solution can be recovered by precipitators A and B, and the precipitation rates of vanadium and molybdenum are 94.8% and 92.6%. Al（OH）3 was prepared from sodium aluminate solution in the carbonation decomposition process, and the purity of Al2O3 is 99.9% after calcination, the recovery of alumina reaches 90.6% in the whole process; the Ni-Co concentrate was leached by sulfuric acid, a nickel recovery of 98.2% and cobalt recovery over 98.5% can be obtained under the experimental condition of 30% H2SO4, 80℃, reaction time 4 h, mass ratio of liquid to solid 8, stirring rate 800r/min.

UV-Catalytic Treatment of Municipal Solid-Waste Landfill Leachate with Hydrogen Peroxide and Ozone Oxidation

The performance of UV/H_2O_2, UV/O_3, and UV/H_2O_2/O_3 oxidationsystems for the treatment of municipal solid-waste landfill leachatewas investigated. Main objective of the experiment was to removetotal organic carbon (TOC), non-biodegradable organic compounds(NBDOC) and color. In UV/H_2O_2 oxidation experiment, with theincrease of H_2O_2 dosage, removal efficiencies of TOC and coloralong with the ratio of biochemical oxygen demand (BOD) to chemicaloxygen demand (COD) of the effluent were increased and a betterperformance was obtained than the system H_2O_2 alone.

Kinetics of nickel leaching from roasting-dissolving residue of spent catalyst with sulfuric acid

Sulfuric acid leaching process was applied to extract nickel from roasting-dissolving residue of a spent catalyst, the effect of different parameters on nickel extraction was investigated by leaching experiments, and the leaching kinetics of nickel was analyzed. The experimental results indicate that the effects of particle size and sulfuric acid concentration on the nickel extraction are remarkable; the effect of reaction temperature is mild; while the effect of stirring speed in the range of 400-1 200 r/min is negligible. Decreasing particle size or increasing sulfuric acid concentration and reaction temperature, the nickel extraction efficiency is improved. 93.5% of nickel in residue is extracted under suitable leaching conditions, including particle size （0.074-0.100） mm, sulfuric acid concentration 30% （mass fraction）, temperature 80 ~C, reaction time 180 min, mass ratio of liquid to solid 10 and stirring speed 800 r/min. The leaching kinetics analyses shows that the reaction rate of leaching process is controlled by diffusion through the product layer, and the calculated activation energy of 15.8 kJ/mol is characteristic for a diffusion controlled process.

试论混合钼精矿的冶炼方法

对铜钼混选矿,采用纯氧焙烧-真空升华的冶炼工艺,试剂投入低,产品档次高。对低钼铜钼混选矿和所有铅钼混选矿以及镍钼矿原矿,采用硫酸加硝酸常压强化催化氧化浸出,可以简化选矿工序,实现铅钼彻底分离,避免铅对钼产品的连环污染。钼和铅外金属元素从浸出液回收,铅和贵金属从浸出渣回收,金属收率高。还介绍了卧式常压强化浸出槽的特点和功能。