Effects of water intrusion on thermal conductivity and durability of carbonaceous rocks

This study aimed to investigate the role of water intrusion on thermal conduction and durability of three types of carbonaceous rock with different mineralogical components. The soaking method was selected to simulate water intrusion, and the respective evolutions of thermal conductivity k and slake durability index I_d2 during soaking period were assessed. Scanning electron microscopy was conducted to explore the mechanism controlling these revolutions. The results revealed that the magnitude of moisture content and density of carbonaceous rocks at their natural state was clearly correlated to the content of illite mineral. Water intrusion was beneficial to the thermal conduction of carbonaceous rocks, where thermal conductivity increased with an increase in soaking time and exhibited a moderate increment after 8 days of soaking. Slake durability index I_d2 was sharply decreased as soaking progressed and reached a low level after soaking. This deterioration in durability was mainly attributed to the absorption of free water, which in turn yields the anisotropic expansion of specific minerals. An unstable structure with more pores and new morphology minerals were identified in carbonaceous rocks at the completion of soaking procedure. An empirical relationship was developed successfully for predicting slake durability index using thermal conductivity.     

Removal of estrone and 17beta-estradiol from water by adsorption

Endocrine disrupting chemicals (EDCs) are the focus of current environment concern, as they can cause adverse health effects in an intact organism, or its progeny, subsequent to endocrine function. The paper reports on the removal of estrone (E1) and 17beta-estradiol (E2) from water through the use of various adsorbents including granular activated carbon (GAC), chitin, chitosan, ion exchange resin and a carbonaceous adsorbent prepared from industrial waste. The results show that the kinetics of adsorption were adsorbent and compound-dependent, with equilibration being reached within 2 h for a waste-derived carbonaceous adsorbent to 71 h for an ion-exchange resin for E1, and within 7 h for the waste-derived carbonaceous adsorbent to 125 h for GAC for E2. Of all the adsorbents tested, the carbonaceous adsorbent showed the highest adsorption capacity, with a maximum adsorption constant of 87500 ml/g for E1 and 116000 ml/g for E2. The GAC also had a very high adsorption capacity for the two compounds, with a maximum adsorption constant of 9290 ml/g for E1 and 12200 ml/g for E2. The effects of some fundamental environmental parameters including adsorbent concentration, pH, salinity and the presence of humic acid and surfactant on adsorption were studied. The results show that adsorption capacity of activated carbon was decreased with an increase in adsorbent concentration and by the presence of surfactant and humic acid. The results have demonstrated excellent performance of a waste derived adsorbent in removing E1 and E2 from water, and indicated the potential of converting certain solid waste into useful adsorbents for pollution-control purposes.     

A new route for the beneficiation of low grade calcareous phosphate rocks

The bulk of the world's phosphate reserves is located in sedimentary horizons that contain appreciable amounts of carbonate. During beneficiation of phosphate rocks, huge amounts of oversize phosphate rocks are rejected from crushers. This reject also mostly contains low tricalcium phosphate content and high carbonate content. In this work, various experiments have been carried out to reduce the carbonate content by leaching the ground phosphate rock with dilute formic acid solution in order to get marketable and industrially acceptable phosphate grades. By using this technique, the effect of formic acid concentration, reaction time, process temperature and liquid/solid ratio (vol./wt. basis) have been studied. It was found that upon treatment of the ground rock with formic acid, the P₂O₅ percent can be raised by up to 29% corresponding to a reduction of about 69% in the calcium carbonate content of the samples, depending on the reaction conditions as well as nature and size of the raw phosphate particles used for analysis.     

影响炭质中间相形成和发展的因素——Ⅱ.添加剂和外加场

在制备炭质中间相的过程中,为了调整中间相形成的速度、获得特种中间相产品或研究中间相的形成机理,研究者们往往向制备中间相的原料中添加某些添加剂,这些添加剂的存在对中间相的形成过程和生成方式产生了影响。另外,在外加场(如力场、磁场、电场)的作用下,中间相分子的取向发展也会受到一定的影响。本文主要讨论添加剂(包括物理添加剂和化学添加剂)存在下中间相形成的特征以及外加场(力场、磁场和电场)对中间相形成和发展的影响,并利用“粒状基本单元构筑”中间相形成理论对这些影响因素的作用机理给予了合理的解释。     

碳质材料脱氧技术在转炉渣的应用

顶吹转炉由于其工艺特点,造成转炉终渣FeO质量分数高等不利因素。为了解决该问题,通过研究碳脱氧的原理,提出了以碳质材料作为炉渣脱氧剂的思路,使用碳质材料降低炉渣中的氧化铁。在工业试验中吨钢加入1.2~2.2kg/t的碳质材料,转炉出钢至1/2时均匀向渣面加入碳质材料,出钢至1/4时加完。结果显示,碳质材料在炉渣脱氧方面具有良好的使用效果,可按照2∶1的比例代替铝,具有明显的经济效益,有利于降低生产成本。     

凉山矿业淌塘铜矿难选铜矿石生产指标优化

本文介绍了凉山矿业淌塘铜矿自投产运行以来,针对该碳质脉石型铜矿生产技术经济指标偏低的现实,在生产过程中分别进行了磨矿一浮选工艺流程和药剂制度的改进,获得铜精矿含铜22％,铜回收率82％,球磨机台效22吨／时。该工艺流程和药荆制度合理效果显著。     

Sorption of indigo carmine by a Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge

Indigo carmine removal from aqueous solution has been evaluated using Fe-zeolitic tuff and carbonaceous material from pyrolyzed sewage sludge treated with HCl (CM). The adsorbents were characterized by scanning electron microscopy, BET surface area and X-ray diffraction. Sorption kinetics and isotherms were determined and the adsorption behaviors analyzed. Kinetic pseudo-second order and Langmuir–Freundlich models were successfully applied to the experimental results obtained with the Fe-zeolitic material, while kinetic first order and Langmuir–Freundlich models were applied to the results from the carbonaceous materials. This indicates mechanisms of chemisorption and physic sorption, respectively, on the heterogeneous materials. The results indicate that the carbonaceous material from the pyrolysis of sewage sludge (sorption capacity 92.83 mg/g) is a better adsorbent of indigo carmine than the zeolitic material (sorption capacity 32.83 mg/g).     

由炭质溶胶-凝胶制备超细炭的研究

以石油生焦为原料,分别以硫酸与硝酸的混合物以及硫酸和双氧水的混合物为氧化剂,分别制得了水性中间相。将水性中间相溶解于乙二醇中制成炭质溶胶凝胶,再经超临界干燥制得超细炭原粉。在氮气的保护下,超细炭原粉于 ５５０℃～１ ２００℃的温度下进行热处理。并利用 Ｆ Ｔ Ｉ Ｒ, Ｔ Ｇ, Ｘ射线衍射和 Ｔ Ｅ Ｍ 等测试技术对超细炭原粉及其热处理产物进行了表征。     

碳系导电纳米材料填充高分子导电复合材料及其研究进展

碳系纳米材料具有优异导电性能,可作为导电填料填充到高分子基体制备导电复合材料。对碳系纳米导电材料分类、导电机理、导电性能及应用领域进行了讨论,对近期研究进展进行简要综述。最后,展望了碳系纳米导电材料填充高分子导电复合材料未来发展趋势并探讨了目前存在的问题。     

Influence of carbonaceous materials on the interactions among (Al2O3-C)/Fe system with temperature and soaking time

It has practical significance for improving the service life of Al₂O₃-C refractories and reducing its influence on steel quality to reveal the reaction mechanism among (Al₂O₃-C)/Fe system under high temperature. The influence of carbonaceous materials on the interactions among (Al₂O₃-C)/Fe system with temperature and soaking time were studied using thermalgravity method in this paper in order to get a better understanding on the reaction mechanism among (Al₂O₃-C)/Fe system. The weight loss of (Al₂O₃-C)/Fe samples and the formation of Al₂O₃ crystal whiskers along with the change of aluminium and carbon content in iron indicates the mechanism of the effects of carbonaceous materials on the reactions among (Al₂O₃-C)/Fe system under high temperature. The result showed that the aluminium pickup of iron was not only due to the dissolution of Al₂O₃ in molten iron but mostly due to the carbothermic reduction of Al₂O₃ and carbonaceous materials in the presence of molten iron.