ULECES: Ultra low energy cement synthesis: A radical process change to achieve green and sustainable technologies

拟议的项目是研究使用熔盐工艺合成水泥矿物粉末。水泥生产的传统方法是在窑中将石灰石和粘土一起加热，温度等于或大于1450摄氏度，然后将材料研磨至所需的粒度。每生产一吨产品就会产生类似数量的二氧化碳，导致全球每年排放18亿吨二氧化碳。因此，水泥在加热和研磨方面具有高的内含能量（高达6吉焦/吨）。此外，水泥是全球重要的产品。它每年用于生产6000 Mm 3的混凝土，全球销售额为450，000 M，混凝土是建筑行业使用的主要材料，该行业占全球GDP的11%（英国GDP的10%），全球雇用超过1亿人（英国150万人）。因此，水泥的全球重要性是毋庸置疑的，但这是以严重的环境影响为代价的，因为水泥市场容量很大，但产品本身的价值相对较低（50美元/吨），水泥行业在进行重大工艺变革以减少排放方面进展缓慢。然而，如果我们认真对待应对气候变化的挑战，就必须开发制造此类产品的新方法，以减少能源需求，从而降低随后的二氧化碳排放水平。该提案旨在通过使用熔盐路线合成无水水泥相来大规模减少水泥生产中的二氧化碳排放量，减少所需的总能量和所涉及的温度，从而使可再生能源与该过程相结合（即通过电加热而不是化石燃料燃烧可以提供较低的温度）。这项工作将应用熔盐体系的平衡热力学模型来指导主要三硅酸钙产品的实验合成，并将研究使用类似路线生产其他主要水泥熟料矿物（对工业有吸引力的定制水泥，因此价值更高，高达250/吨）的可能性。每种合成路线的能量需求将与熔体中化合物形成的化学动力学一起确定，而关键的高温分离阶段将通过实验进行研究。研究结果将大大有助于优化新工艺的商业开发。该提案代表了一种创新的、激进的方法，通过开发新颖、复杂的化学和高温（高达800摄氏度）工艺工程来开发绿色和可持续技术。拟议的工作方案是多学科性质的，涉及化学工程师、材料科学家、化学家和地球化学家，并包括水泥制造、其化学和物理特性以及熔盐系统方面的高级专门知识。

The proposed project is to investigate the synthesis of cement mineral powders using a molten salt process. The conventional method of cement production is to heat limestone and clay together in kilns at temoeratures equal to or greater than 1450 degC and then to grind the material to the required particle size. For each tonne of product a similar amount of CO2 is produced, leading to global emissions of 1,800 Mt CO2 per annum. Cement therefore has a high embodied energy (up to 6 GJ/tonne) in terms of heating and grinding. In addition, cement is a globally important product. It is used to produce 6000 Mm3 of concrete annually at a global sales value of 450,000M and concrete is the principal material used by the construction industry, a sector that accounts for 11% of global GDP (10% of UK GDP) and employs more than 100 million people worldwide (1.5M in the UK). Hence, there is no doubt of the global importance of cement, which comes at the price of significant environmental impacts.Since the market for cement is of very high volume but the value of the product itself is relatively low (50/tonne), the cement industry is slow to incorporate significant process changes to reduce its emissions. However, if we are serious about meeting the challenges of climate change, new methods of manufacturing such products must be developed to reduce the energy demand and, hence, the subsequent CO2 emission levels. This proposal seeks to do just that, by massively reducing the emissions of CO2 from cement production through the novel synthesis of anhydrous cement phases using a molten salt route, reducing the total energy required and the temperatures involved, thereby allowing renewable energy sources to be integrated with the process (i.e. lower temperatures can be provided by electric heating, rather than by fossil fuel firing). The work will apply equilibrium thermodynamic modelling of molten salt systems to guide experimental synthesis of the main tri-calcium silicate product and will also investigate the possibility of using similar routes to produce other principal cement clinker minerals (bespoke cements that are attractive to industry and are, hence, of higher value, up to 250/tonne). The energy requirements of each synthetic route will be determined alongside the chemical kinetics of formation of the compounds in the melts, whilst the crucial high-temperature separation stage will be investigated experimentally. The results of the research will go a long way to optimising the new process with respect to commercial exploitation.This proposal represents an innovative, radical approach to the development of green and sustainable technologies through the development of novel, complex chemistry and high-temperature (up to 800 degC) process engineering. The proposed work programme is multidisciplinary in nature, involving chemical engineers, material scientists, chemists and geochemists and incorporating a high level of expertise in the manufacture of cement, its chemical and physical properties and in molten salt systems.