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高时，矿物悬浮液的有效和一致的过滤可能受到不期望的流变效应的阻碍。红石膏就是这样一种材料，当二氧化钛生产过程中产生的废硫酸用石灰石、石灰或两者的组合中和时就会产生。红石膏的可持续利用率很低，由于处理困难和杂质含量高，每年有大量红石膏被浪费在垃圾填埋场。以前的工作集中在红石膏的元素和微观分析，以提出潜在的用途，但对工艺条件，颗粒结构发展和所得性能之间的关系了解较少[1]。在这项工作中，工业红石膏的样品将进行表征，以调查颗粒形态和杂质或其他相的存在，数量和状态。这些将与基于过滤和流变学的性能测量相关联，以确定不良行为的潜在来源。重要的是要了解红石膏的脱水水平，以避免触变性等行为，以及如何将这种水掺入矿物结构中使其难以过滤。特别地，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处的潜在积聚。在实验室规模下复制石膏结晶工艺并增加工艺控制，将允许条件的单独变化，以确定特性和性能的差异，这是目前在工艺规模下不可能实现的步骤。发展一种可以改善红石膏结构特征的理解，可以有助于提高利用率和减少这种潜在有价值的工艺副产品的浪费。