Valorisation of red gypsum through understanding of structure-processing-property relationships across scales

通过理解跨尺度的结构-加工-性能关系来评估红石膏的价值

• 批准号: 2746338
• 金额: --
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2746338
• 关键词: Valorisation; red; gypsum; through; understanding

Effective and consistent filtration of mineral suspensions can be hindered by undesirable rheological effects when moisture content of the mineral phase/s is high. Red gypsum is such a material and is produced when waste sulfuric acid from titanium dioxide manufacture is neutralised with limestone, lime, or a combination of the two. Sustainable utilisation of red gypsum is low and significant volumes are wasted in landfill annually, due to handling difficulties and high levels of impurities. Previous work has focused on elemental and microscopic analysis of red gypsum to suggest potential uses, but there is less understanding of the relationships between the process conditions, structural development of particles, and the resulting performance [1]. In this work, samples of industrial red gypsum will be characterised to investigate particle morphology and the presence, quantity, and state of impurities or additional phases. These will be linked to performance measures based on filtration and rheology to identify potential sources of undesirable behaviour. It is important to understand the level of dewatering of red gypsum that is required to avoid behaviour such as thixotropy, and how the incorporation of this water into the mineral structures makes it difficult to filter. In particular, particle shape and size distributions should be controlled alongside the presence of impurities and additional phases when considering permeation of water through a filter cake, in order to avoid potential build-up of smaller particles or impurities at the filter medium. Replication of the gypsum crystallisation process at the lab scale with increased process control will allow isolated changes in conditions to identify resulting differences in characteristics and performance, a step that is currently not possible at the process scale. Developing an understanding that can lead to improvement in the structural characteristics of red gypsum can contribute to increased utilisation and a reduction in waste of this potentially valuable process by-product.

当矿物相的水分含量较高时，不良的流变效应可能会阻碍矿物悬浮液的有效且一致的过滤。红石膏就是这样一种材料，是用石灰石、石灰或两者的组合中和二氧化钛生产中的废硫酸而产生的。由于处理困难和杂质含量高，红石膏的可持续利用率很低，每年在垃圾填埋场浪费大量红石膏。以前的工作主要集中在红石膏的元素和微观分析上，以提出潜在的用途，但对工艺条件、颗粒结构发展和最终性能之间的关系了解较少[1]。在这项工作中，将对工业红石膏样品进行表征，以研究颗粒形态以及杂质或附加相的存在、数量和状态。这些将与基于过滤和流变学的性能测量联系起来，以识别不良行为的潜在来源。重要的是要了解避免触变性等行为所需的红石膏脱水水平，以及这种水如何融入矿物结构使其难以过滤。特别是，当考虑水通过滤饼的渗透时，颗粒形状和尺寸分布应与杂质和附加相的存在一起控制，以避免较小颗粒或杂质在过滤介质上潜在的堆积。在实验室规模上复制石膏结晶过程并加强过程控制，将允许条件的单独变化，以确定由此产生的特性和性能差异，这一步骤目前在工艺规模上是不可能的。加深对红石膏结构特性的了解，有助于提高这种具有潜在价值的工艺副产品的利用率并减少浪费。