Measurement and Improvement of Carbon Anode Properties

碳阳极性能的测量和改进

• 批准号: RGPIN-2014-05439
• 负责人: Kocaefe, Duygu
• 金额: $ 1.46万
• 依托单位: Université du Québec à Chicoutimi
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=588422
• 关键词: Measurement; Improvement; Carbon; Anode; Properties

The objective of the current research proposal is to develop methods to characterize the anode behavior (thermal expansion, cracking) during baking, to improve the wettability of coke by pitch, and to decrease the reactivity of anodes made with low sulfur coke. These projects are original and fundamental in nature. Project 1- Improvement of the wettability of coke by pitch using surfactants: Pitch is the binder and has to be mixed well with the dry aggregate. During baking, pitch carbonizes and forms links between the dry aggregate particles. Thus, it has to wet the dry aggregate well which will in turn result in denser anodes. The wetting of coke by pitch involves chemical and physical interactions. Surface functional groups play an important role in wettability. In this project, the effect of surface functional group modifications and addition of surfactants on wettability of coke by pitch will be studied in order to improve the pitch/coke interactions. Wettability experiments will be carried out before and after surface modifications. The carbonization level of pitch will be determined in TGA, and the interactions will be characterized using different techniques such as FTIR and XPS. Project 2- Decreasing the reactivity of anodes made with low sulfur coke: Sulfur (S) plays a significant role in inhibiting the catalytic effects of metals such as vanadium (V) and nickel (Ni) on anode reactivity. On the other hand, approximately 95% of the SO2 emissions generated by smelters can be attributed to S found in the petroleum coke. Therefore, S content of the coke has to be optimized. Many coke suppliers mix high and low S cokes to have an anode-quality coke. The objective of this project is to treat low S cokes so that the anodes produced with them have low anode reactivity in addition to low SO2 emissions. To reduce the reactivity of anodes made with low S coke, it is necessary to add some compounds which can counteract the catalytic activities of transition metals. In this project, different additives will be used. These will be added to the raw materials, and anodes will be made and baked in the UQAC laboratory. Then, the reactivities of these anodes will be tested. Project 3- Measurement of the thermal expansion coefficient (TEC) with image analysis during baking: During baking, anodes go through dimensional changes (expansion around 150-200ºC and contraction as the baking continues). The characterization of these dimensional changes would yield valuable information (especially on cracking) to help improve the anode quality. However, the measurement of TEC is generally carried out for baked anodes. The equipment cannot handle green anodes due to devolatilization. The objective of this project is to measure the dimensional changes of anode samples during baking using the image analysis which is a nonintrusive technique. These data are necessary for modeling the behavior of anodes in the baking furnace. Also, a comprehensive understanding of the factors affecting these changes will help reduce anode cracking. Project 4- Detection of crack formation during baking using audible sound: Cracks in anodes can be investigated indirectly after baking by measuring different properties (such as density) of the anode cores. There are also direct methods such as tomography or microscopy which allow the study of crack formation. All of these approaches indicate cracks of the final product at room temperature, and none shows at which stage of baking the cracks form. This information would reveal the causes of cracks. The objective of this project is to detect the stage and the position of crack formation and growth during baking using audible sound. Such information will help adjust the baking conditions to obtain better anode quality.

目前的研究方案的目的是开发方法来表征焙烧过程中的阳极行为(热膨胀、开裂)，改善焦炭在沥青中的润湿性，并降低用低硫焦炭制成的阳极的反应性。这些项目具有原创性和基础性。 项目1--通过使用表面活性剂的沥青改善焦炭的润湿性：沥青是粘合剂，必须与干燥的集料充分混合。在烘焙过程中，沥青碳化，并在干燥的集料颗粒之间形成联系。因此，它必须很好地湿润干燥的聚集体，这反过来会导致更致密的阳极。沥青对焦炭的润湿包括化学和物理相互作用。表面官能团对润湿性起着重要的作用。为了改善沥青/焦炭的相互作用，本项目将研究表面官能团的改性和表面活性剂的添加对焦炭在沥青上的润湿性的影响。润湿性实验将在表面改性前后进行。沥青的碳化程度将在热重分析中确定，相互作用将使用不同的技术来表征，如FTIR和XPS。 项目2-降低用低硫焦炭制成的阳极的反应性：硫(S)在抑制钒(V)和镍(Ni)等金属对阳极反应性的催化作用方面起着重要作用。另一方面，冶炼厂产生的二氧化硫排放中，约有95%可归因于石油焦中发现的S。因此，S焦炭的含量必须进行优化。许多焦炭供应商将高、低S焦混合在一起，就可以得到阳极质量的焦炭。该项目的目标是处理低S焦炭，使其生产的阳极除了具有低SO2排放外，还具有低的阳极反应性。为了降低低S焦制得的阳极的反应活性，有必要添加一些能够抵消过渡金属催化活性的化合物。在这个项目中，将使用不同的添加剂。这些将被添加到原材料中，并在UQAC实验室制作和烘焙阳极。然后，将测试这些阳极的反应性。 项目3-在烘烤过程中用图像分析测量热膨胀系数(TEC)：在烘焙过程中，阳极经历尺寸变化(150-200℃左右膨胀，随着烘焙的继续而收缩)。对这些尺寸变化的表征将产生有价值的信息(特别是关于开裂的信息)，以帮助提高阳极的质量。然而，TEC的测量通常是对焙烧的阳极进行的。由于脱挥发，设备不能处理绿色阳极。本项目的目标是利用图像分析这一非侵入性技术来测量阳极样品在焙烧过程中的尺寸变化。这些数据对于模拟焙烧炉中阳极的行为是必要的。此外，全面了解影响这些变化的因素将有助于减少阳极开裂。 项目4-使用声音检测焙烧过程中裂纹的形成：通过测量阳极芯的不同性能(如密度)，可在焙烧后间接调查阳极中的裂纹。也有直接的方法，如断层摄影术或显微镜，可以研究裂纹的形成。所有这些方法都显示了最终产品在室温下的裂纹，但没有一种方法表明裂纹是在哪个烘烤阶段形成的。这些信息将揭示裂缝的原因。本项目的目标是利用可听声音检测烘烤过程中裂纹形成和扩展的阶段和位置。这些信息将有助于调整焙烧条件，以获得更好的阳极质量。